V2_Raymond Tan_H0604673_Report

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SCHOOL OF SCIENCE AND TECHNOLOGY
ENG 499
ENHANCED COUPLING OF A KA-BAND
NARROW BAND PASS FILTER USING LTCC
TECHNOLOGY
PREPARED BY
STUDENT PI
SUPERVISOR
PROJECT CODE
: Tan Puay Thiam
: H0604673
: LUM KUM MENG
: JAN2010/ENG/0070
A project report submitted to SIM University
in partial fulfilment of the requirements for the degree of
Bachelor of Engineering
Page 1 of 83
1
ACKNOWLEDGEMENT
I would like to express my most sincere gratitude to my supervisors Dr. Lum Kum Meng for
their invaluable guidance, suggestions, and constructive criticisms during the investigation of
the project and the preparation of this thesis.
At the same time, I would like to thank my friends and colleagues from our microwave group
and ST Electronics for their support and kind assistance.
Finally, I would like to express my appreciation to my family and friends, from whom I
received much encouragement in the project.
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Table of Contents
1
ACKNOWLEDGEMENT .......................................................................................... 2
2
PROJECT DEFINITION .......................................................................................... 5
2.1
2.2
2.3
Project Objective .................................................................................................................... 5
Overall Objective .................................................................................................................... 5
Approach and method to be employed ................................................................................ 6
2.3.1
Stage 1: Design a end Coupled pass filter enhanced coupling of Ka-Band in LTCC. ............ 6
3
PROCESS FLOW TO DESIGN THE FILTER, ASSEMBLE & MEASUREMENT .. 13
4
LITERATURE REVIEW......................................................................................... 14
4.1
4.2
RF Filter Design ....................................................................................................................14
Why using ADS tool? ...........................................................................................................18
4.2.1
Featuring of ADS Momentum ............................................................................................... 19
LTCC features with some application ................................................................................20
4.3.1
LTCC Process ........................................................................................................................ 22
Microstrip ..............................................................................................................................25
4.4.1
Other types of MICROSTRIP ............................................................................................... 26
4.4.2
Typically there are 5 types of Microstrip filter: ..................................................................... 27
Microstrip Resonator ...........................................................................................................28
MicroStrip Transmission Line .............................................................................................29
Coupled Microstrip lines .....................................................................................................31
FR4 Process Methodology ..................................................................................................33
4.8.1
Plating Process Options ......................................................................................................... 34
4.8.2
Tin/Lead Alloy Plating .......................................................................................................... 34
4.8.3
Ni/Au Electroless or Immersion Plating Process for Soldering ............................................. 34
4.8.4
Alternatives to Alloy Plating ................................................................................................. 34
4.8.5
Process on Organic Solderability Preservative (OSP) ........................................................... 34
4.8.6
Assembly Process Compatibility ........................................................................................... 35
4.8.7
Limited Shelf Life for OSP Coated Boards ........................................................................... 36
4.8.8
Benefits of Coated Surfaces................................................................................................... 36
4.8.9
Concerns of Coated Boards ................................................................................................... 36
4.8.10 Advantage on FR-4-86 material for Microwave and RF applications ................................... 36
4.8.11 ADS implementation ............................................................................................................. 37
4.8.12 Calculation Method ............................................................................................................... 38
4.8.13 Determine the microstrip guided wavelength ........................................................................ 39
4.3
4.4
4.5
4.6
4.7
4.8
5
FILTER IMPLENTATION IN ADS ......................................................................... 40
5.1
5.2
Setting of substrate Parameters in LTCC ..........................................................................40
5.1.1
Set up of Montenum under ADS ........................................................................................... 41
Setting of substrate Parameters in FR4 .............................................................................43
6
FABRICATION ON FR4 END GAP COUPLED .................................................... 46
6.1
6.2
6.3
Process of FR4 from supplier .............................................................................................47
Hardware Mounting 1 ( Initial Design) ................................................................................48
Hardware Mounting 2 ( Final Design) .................................................................................49
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7
HARDWARE MEASUREMENT ............................................................................ 50
7.1
Hardware Measurement Set Up ..........................................................................................50
7.1.1
Measurement Result .............................................................................................................. 51
7.1.2
Summary of the end-gap coupled multilayered FR4 BPF ..................................................... 52
7.1.3
Conclusion ............................................................................................................................. 52
8
GANTT CHART .................................................................................................... 53
9
APPENDIX A ........................................................................................................ 54
9.1
9.2
9.3
Website ..................................................................................................................................55
Appendix B............................................................................................................................57
Appendix C: Software simulation for FR-4 .......................................................................60
9.3.1
Appendix D: Software simulation for FR-4.......................................................................... 62
9.3.2
Appendix E: Software simulation for FR-4 .......................................................................... 67
Appendix F: Meetings Logs ...............................................................................................74
9.4
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2
PROJECT DEFINITION
2.1
Project Objective
The main intention for this project is to design an enhanced coupling of a KA-BAND
(26~40GHz) Narrow Band-Pass Filter using Low Temperature co-fired ceramics (LTCC)
Technology.
Scopes include:
a) Reviewing the literature and understanding of LTCC technology.
b) Evaluating current filter designs for LTCC applications.
c) Design a narrow band filter according to LTCC specification.
d) Illustrate a few filter designs using ADS software simulation.
e) Research on FR4 printed circuit board.
f) Design and simulate a narrow band filter using FR4 material.
g) Illustrate a few filter designs using ADS software simulation.
h) Draw out Gerber file and send for fabrication.
i) Inter connect of PCB using SMA connectors for ribbon bonding or soldering.
j) Using instruments like Scalar Network Analyzer or Vector Network Analyzer
(VNA) to measure the response of the filter.
k) Analyser for further modification and improvement to accomplished the proct.
2.2
Overall Objective
Microwave filters are essential components in modern wireless communication systems.
RF band pass filter are sometimes required for the separation of up link and downlink
transmission paths. Narrow band filters are used for the rejection of the image channel as
well as any strong interfering signal in nearby frequency band.
Recently the used of low temperature co-fired ceramic (LTCC) technologies broadly
enchant more RF engineer attentions for their superior advantages over other substrate
technologies. However, is not like a normal organic PCB but the general concept is
reminded and the result is monolithic ceramic multi layers. Three dimensions in 3-D
integration capabilities that create extend compendium and low costs design. Small value
of dielectric loss tangents reveals very high excellent frequency characteristics[1].
Microwave BPFs have been employing more advantages of the LTCC technologies less
than 10GHz [2][3].
End coupled Ka-Band pass filter adopting 3-D multilayered LTCC technology. Even
though the end-coupled Band Pass Filter has a narrow bandwidth characteristic the same
as other filter structures, the shrinkage and restricted resolution of LTCC process make it
very difficult to control the absolute gap between the two adjacent resonators close
enough coupling on the same planar substrate. Minimum spacing for the adjacent
conductors is 150 micro meter with screen-printing LTCC process too large for the
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wanted series capacitive coupling between adjacent resonators. Positions on the
microstrip resonators on different layers in the multilayered structure abolish those
process limitations by vertically isolate the adjacent resonators with an intermediate
LTCC tape. In addition overlapping two adjacent ends of resonators can determine the
filter characteristics, the bandwidth, sharpness and minimum insertion loss in pass
band[4].
2.3
Approach and method to be employed
To commutate the objective of the project, a prerequisite project management is
necessary. Execution of various tasks must be strictly adhered.
The project progress is broken down into stages:
1ST STAGE:
1) Design a narrow band pass filter enhanced coupling 3th order of a Ka-Band in
LTCC.
2) Simulate the filter using Advanced Design System tools.
3) Enhanced and simulate to get better result.
2nd STAGE:
1)
2)
3)
4)
5)
6)
7)
2.3.1
Design a narrow band pass filter on FR4 material.
Enhanced to simulate and testing to get better S21 nearly to 0dB.
Thick Film Fabrication on ceramics substrates
Test Fixtures
Testing and measurement
Project evaluation
Enhancement of design
Stage 1: Design a end Coupled pass filter enhanced coupling of KaBand in LTCC.



Understand and research of band pass filter enhanced of a Ka-Band.
Have a clearer view which type and stages of filter to be used.
Advantage and disadvantage of LTCC.
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Stage 2: Simulate the filter using Advanced Design System tools.







Understand the circuit simulation of a filter whereby the input signal defined
as modulation of the carrier,V(t) and the RF carrier and its harmonics in the
frequency domain. Time steps and total time interval also defined.
When simulation is running, the spectrum at the output and other nodes is
completed at each time point. The results make its available of the amplitude
and the phase of any spectral component as a function of time.
If any large signal of S-parameter needs to be done at two-port, the simulator
can performs.
Terminate port 2 with the complex conjugate of its reference impedance.
Apply a signal with a specific power level P1 at port 1, using the source
whose impedance equals to the complex conjugate of the port’s reference
impedance.
Use harmonics balance, calculate the currents and voltages at port1 and port
2. Use this information to calculate S11 and S21.
Terminate port 1 with the complex conjugate of its reference impedance.
Apply a signal of power P2=[S21]P1 at port 2. Using harmonics balance
calculates the currents and voltages at port 1 and port 2. Use this information
to calculate S12 and S22.
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Stage 3: Enhanced and simulate to achieve better result



10 simulation layout and result based on a Ka-Band Narrow Band Pass
Filter using LTTC technology.
The design was base on third order gap coupled multilayered LTCC BPF
characteristics according to Matthaei, Young and Jones synthesis
method[5].
This overlapping design of two adjacent ends of resonators can control
filter characteristics.
Centre Freq (fo) = 30.23GHz
Lower Band Edge (fL)= 29.77GHz
Upper Band Edge (fH)= 30.68GHz
Fractional Bandwidth (w)= 3.0% where ((fH-fL )/fo)x100%
Min insertion loss= 3.12dB
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2.3.1.1 Stage 1: Design a narrow band pass filter on FR4 material.




Research and understand how to calculate narrow end coupled band filter
with FR4 material for 1.5GHz.
Have a clearer view which type and stages of filter to be used.
Advantage and disadvantage of FR4.
Enhanced result for s11 & s21.
Centre Freq (fo) = 1.494GHz
Lower Band Edge (fL)= 1.426GHz
Upper Band Edge (fH)= 1.550GHz
Fractional Bandwidth (w)= 8.299% where ((fH-fL )/fo)x100%
Min insertion loss= 3.148dB
Stage 2: FR4 Fabrication on printed circuit board and its features






Multifunctional laminates, Tg 140ºC (DSC)
Excellent electrical properties for standard loss material.
Exceptional consistent laminate quality due to exclusive use of Nan Ya’s raw
materials.
Common PTH process parameters result in very good through hole reliability
and copper foil peel strength.
90 min press at 182°C and 200-300psi.
High luminance of Epoxy contract with copper for laser type AOL
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Stage 3: Test Fixtures (Optional)





A required or optional in mechanical housing and a transition between the
microstrip circuit and the co-axial connectors. Example SMA connectors,
APC3.5 etc. which are gold plated.
Ensure clean surface when connecting free from oxidation.
The coax usually has larger cross section than the microstrip and requires
the uses of tapering either continuously or in steps.
Launchers connect directly to the microstrip might be solder or using ribbon
bonds attach below the connector depends on which material uses in
microstrip. A typical launcher cross section shown in Fig 1.3.1.1
Some design principles need to be follow
1.
2.
3.
4.
5.
The housing wall or centre pin should be 50Ω coax line.
Centre must not be wider than 50Ω microstrip line.
No gap between the carrier and the side of housing.
Substrate height must be not so small that the ground interferes with the
coaxial fields at launcher pin end.
No air gaps should exist in between the microstrip ground plane and the
housing base.
Fig 1.3.1.1
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Stage 4: Testing and Measurement





Using a Network Analyzer, self calibration on the equipment, that includes
cal “Short” and “Open”.
Connect DUT (Fixtures with Filter) input to Port 1 and the output to Port 2.
Commonly measure are insertion loss, bandwidth and out of band rejection.
Measure how well the filter passes through signals within its bandwidths
while simultaneously rejection signals well outside that same bandwidth.
Return loss is plot showing high reflection in the stopbands and good
impedance matching in the same band.
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Stage 6: Project Evaluation

At these stage, simulated and tested resulted should be approximately the same
that meets the objective. Limitation or enhanced improvement should be added
in at the second stage of the design.
Stage 7: Enhancement of design

After comparing the result, the parameter of this project must be evaluated to
improve the filter design. Lists of areas we should look into



Return loss should be as low as possible.
There should be nearly 0dB insertion loss ideally.
Maintain the filter shape of the pass band pattern.
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3
PROCESS FLOW TO DESIGN THE FILTER, ASSEMBLE &
MEASUREMENT
Start
A
Design and
range of filter
select
Select Software simulation .
Use ADS tools and design
the filter
Objective
Met?
Yes
No
Compare simulation and test
result
the
Objective
Met?
Rework on
assemble
hardware
Yes
Re-simulate
the filter at
least few times
on 1st design
Compare simulation and test
result again
Simulate and fabrication using
FR4 material on 2nd design
Fabrication the test
fixture.(Optional)
No
Objective
Met?
No
Design and
Fabrication error.
Retune the Filter
Yes
Final Assembly
Assemble to test fixture by using
Epoxy or Eutectic method in the
housing
and
assemble
the
connector.
Perform measurement using
Network Analyzer
End
A
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4
4.1
LITERATURE REVIEW
RF Filter Design
Radio Frequency (RF) defined as a class of electronic filter to operate at the low to high
frequency signals. This frequency range for example can be use in broadcasting, mobile,
WI-Fi etc. This RF devices which will include some of the filtering signals for
transmitted or received. It also can be used as a blocking of duplexers or to separate
certain frequency bands.
Generally there are 4 types of filters that we know.
 Low Pass Filter
 High Pass Filter
 Band Pass Filter
 Bandstop Filter
For Low Pass Filter we knows it allow lower frequency signals to be transmitted from the
input to the output with little attenuation. Moreover, if the frequency exceeded a certain cut
off point, the attenuation increases significantly of the result to deliver amplitude reduced
signal to the output port.
For High Pass Filter is the opposite of low pass filter. The lower frequency components are
higher to the signal attenuated or reduced in amplitude while a cut off frequency point the
signal passes through the filter with little attenuation.
For Band Pass or Band Sop Filter restricted the band pass between certain or specific lower
and upper frequencies point where the attenuation is either low in Band pass or high in
Band stop compared the rest of the remaining frequency band.
Below on Fig 4.1.A shows the summary of the behaviors on ideal 4 types of filters of their
attenuation  in dB versus normalized angular frequency in Ω behavior.
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Figure 4.1.A
The parameter Ω=    / c as a normalized frequency with respect to the
angularfrequency c which denotes the cut off frequency for low pass and high pass
filter and centre frequency for pass band and band stop filter. This normalization will
simplify in developing standard filter approaches. Actual attenuation profile in Figure
4.1.B show three type of low pass filter which are:



Binomial Filter (Butterworth)
Chebyshev Filter
Elliptic (Cauer) Filter
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Figure 4.1.B
The Binomial Filter normally called Butterworth exhibits a monotonic attenuation profile
that easily to implement. But to achieve a steep attenuation transition from pass to stop band
a large number of component is needed. A better steeper slope can be implemented if one
permits a certain degree of variations or ripples in the pass band attenuation profile.
As for Chebyshev filter each ripple to maintain equal number of amplitude either in stop
band or pass band. Both Binomial and Chebyshev attenuation approach to infinity as
  .
As for Elliptic filters which allows the steepest transitions from pass band to stop band at the
expense of ripples in both hands.
Analyzing the various trade offs when dealing with filters which described below in Figure
4.1.C:
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Insertion Loss
Ripple
Bandwidth
Ideally perfect filter
inserted into RF circuit
path which introduced no
power loss in the pass
band. In reality, we
expect a certain power
loss associated with the
filter. Its quantifies how
much below 0dB line
power amplitude
response drops.
Flatness of the signal in
the pass band quantified
by specifying the ripple
between maximum and
minimum amplitude
response in dB or
Nepsers.
For band pass filter, the
bandwidth defines
between upper and lower
frequencies typically
recorded at the 3dB
above the pass band
Shape Factor
Rejection
Its describes the
sharpness of the filter
response by taking the
ratio between 60dB and
the 3dB bandwidths
Obtain infinite
attenuation level at the
undesirable signal
frequencies. In reality
expect the upper bound
due to deployment of a
finite number of filter
components. Practical
design often specifies
60dB as the rejection
rate.
Figure 4.1.C
Page 17 of 83
4.2
Why using ADS tool?
In the commercial worlds, there lot of software for filter simulation. For example,
 Sonnet
 High Frequency Structure Simulator (HFSS)
 Advanced Design System (ADS)
Fig 4.2.A shown comparison between 3 software simulations.
Software
HFSS
Sonnet
Advanced Design
System
1
Automation software for RF.
Most innovative and
Full wave EM simulation for High frequency industry as a
commercially such as Xhigh frequency/ High speed developer and supplier of
parameter & 3D EM
Components. Eg Circuits,
innovative planar EM
simulators use in wireless
connectors and filter.
analysis tool
communication industries
and defence industries.
2
Integrates with many
software through Ansoft
designer environment access
to HFSS. Nexxim circuit
simulator and Slwave signal
integrity analysis tool.
EM simulation tools
analyzing 3-D plannar
circuits including
Microstrip, Stripline, Printed
circuit board with multilayer
Provide full standard based
design and verification using
in wireless libraries and
system EM-co simulation
integrated platform.
Figure 4.2A
Page 18 of 83
Why choosing ADS?
ADS come with some benefits that I would like to proposal in my filter project.





A high low frequency and high speed platform for engineers to do co-design
of integrated circuit, module, and printed circuit board for filters.
Its help the designers work with a single EDA platform to share simulation
models and to minimize design for rework, costs and delays in
communications.
ADS also supported by 3th party by leading industry and foundry partner.
Accuracy and integrate fast for ease of use in the system for circuit & EM
simulators and able to first pass deign in a complete desktop flow.
There is a Demo on how to design a filter on ADS on youtube.
Courtesy from:
http://www.youtube.com/watch?v=2bgk0dnNjaY&feature=player_embedded#
4.2.1
Featuring of ADS Momentum
The Momentum simulator uses the actual physical layout of the device to perform the
simulation. ADS convieniantly translates the parameters entered into the circuit diagram
into real shapes in the layout side of the program. The user then pieces together the parts
to make the device. The translator tries to piece them together, but often fails.
After the substrate is entered, the substrate Green's functions must be calculated. These
are needed for the momentum method and are independent of the actual shape of the
signal conductors. They can, therefore , be computed before the bulk of the simulation
and be reused. Momentum then needs to define a mesh for the simulation. Here, the user
has some input as to how fine the mesh is laid out. The default resolution is 30 cells per
wavelength. This, along with the maximum frequency of the simulation determines the
mesh. Momentum will draw rectangles and triangles that approximate the signal artwork.
This should give an idea of the minimum feature that affects the results.
Momentum uses the "method of moments" to solve for currents and the fields are inferred
from the currents. The distributed element is broken into discreet cells. Each cell is
replaced with a capacitor to ground and an inductor to each neighboring cell. The major
task of the simulator is to solve for the currents by inverting large matrices.
Page 19 of 83
4.3
LTCC features with some application
LTCC technology has per nature a number of interesting features applications:

Very good electrical characteristics and stability up to millimetre waves. The
inherent properties of the material are insensitive to moisture influence and
degrade largely many organic compositions. Depending on the material used,
dielectric constants are between 6 and 9 in GHz range, loss tangent between
0.001 and 0.006.

Very good outstanding dimensional and mechanical stability because of glass
ceramic nature. Not only the TCE is low from 5 to 7 ppm/ C the thermo
mechanical properties have very elastic reversible behaviour largely beyond
the use of the temperature range.


Low TCE is a great advantage of ceramics close to semi conductor (Si, GaAs,
LnP) TCEs facilitating their chip use in chips and wires or flip chip form..
LTCC very adapted to short wedge bonding due to patterning and machinery
precision ability. Its also allows better maintaining alignment over temperature
span.
Firing temperature below 900 C make it good thermal conductivity because
of dielectric has only very fair intrinsic thermal conductivity value from 2 to 4
W/m. C and is approximately much higher quality than organic PCBs. More
importantly there was improvement on the application of thermal up to
50W/m. C .

Very dedicated patterning from direct printing and photo- imageable.

3D capability to design as cavities, holes and fences.

Hermetic and Brazing feasibility.

Proven to be reliability and cost effectively demanding on applications like
aerospace and automotive.
Page 20 of 83
Some Application and Example by using LTCC technology
No.
Application
Frequency
1
Edge Coupled Band Pass Filter
(24.1~25.5) GHz
2
Wilkinson Power Divider
Networks (Strip-line & MicroStrip)
(17.~26) GHz
3
Shield Strip-line Band Pass
Filter with ground to ground via
chains
(24.5+25.5) GHz
4
Multiplier (x3)
(8.5~25.5) GHz
5
Balanced Push Pull Amplifier
6
Band Pass Filter
7
Packaged Microstrip BP-Filter
Photo
GSM 900
(24.5~25.5) GHz
(39~43) GHz
Courtesy by http://www.ltcc.de/en/examples.php
Page 21 of 83
4.3.1
LTCC Process

Slitting:
Greensheets are shipped on a Roll and tapes have to be unrolled onto a clean,
stainless steel table. The sheet has been cut with a razor, laser or a punch into
parts (these parts have to be a little larger than the blank size, if the material needs
to be preconditioned). If a laser is used it is very necessary to control the power to
avoid firing of the sheets.
(a) Preconditioning:
Some tapes need to be preconditioned (e.g. Dupont GreenTape); that
means the greensheet has to be baked for about half an hour at 120°C
(depends on manufacturer and material). Normally the tapes are shipped
with an applied foil / bake sheet, which has to be removed before
lamination at the latest; some processors use this foil as a filling mask for
the vias.
(b) Blanking:
A blanking die is used to create orientation marks and lamination tooling
holes and the final working dimension in case of to be preconditioned
tapes.

(c) Forming vias:
Vias may be punched or drilled with a laser (low power).
Filling vias:
Vias can be filled with a conventional thick film screen printer or an extrusion via
Page 22 of 83
filler.
In the first case the tape has to be placed on a sheet of paper which lays on a
porous stone; a vacuum pump holds the tape on his place and is used as an aid for
via filling.
Note: The possibilities of this method are limited; the vias must have a larger
diameter than tape thickness. The smallest possible size of vias to be filled also
depends on the viscosity of the paste.

The second possibility to fill the vias is to use a special extrusion via filler that
works with pressures of about 4 to 4.5 bar.
Both methods need to have a mask; this mask should be made of a 150-200mm
thick stainless steel. An alternative to that is to use the (Mylar-)foil the tape
usually is applied on.
For the filling of blind vias it is advisable to form the holes concerned of the
masks a little smaller than the diameter of the blind vias. Otherwise there could
occur problems with the filling rate.

Printing:
Cofireable conductors etc are printed on the green sheet using a conventional
thick film screen printer. The screens are standard (250 – 325) emulsion type
thick film screens. Just like the via printing process, a porous stone is used to hold
the tape in place. Printing of the conductor tends to be easier and of higher
resolution than standard thick film on alumina. This is due to the flattness and
solvent absorption of the tape. After printing, the vias and conductors have to be
dried in an oven at 80 to 120°C for 5 to 30 minutes (depends on material); some
pastes need to level at room temperature for a few minutes before drying.
Note: Resistors may vary their value when terminated with different conductors.
With the help of a Micro-Screen printer, it is possible to print conductors with a
50mm line resolution.

Register for Lamination:
Each layer is placed in turns over tooling pins.
Some processors use a heat pliers to fix the sheets in turns one on top of the other.

Lamination:
There are two possibilities of laminating the tapes.
The first is named uniaxial lamination; the tapes are pressed between heated
platens at 70°C, 200 bar for 10 minutes (typical values). This method requires a
180° rotation after half the time. The uniaxial lamination could cause problems
with cavities / windows. This method causes higher shrinking tolerances than the
isostatic lamination.
Page 23 of 83

The main problem is the flowing of the tape; that results in high shrinkage
tolerances (especially at the edge of the part) during the firing and varying
thicknesses of single parts of each layer (causes hard problems on the high
frequencies sector).
The second way is to use an isostatic press. The stacked tapes are vacuum sealed
in a foil and pressed in hot water (temperature and time are just the same like
using the uniaxial press). The pressure is about 210 bar.
Note: deep cavities and windows need to have an inlay during lamination.

Cofiring:
Laminates are fired in one step on a smooth, flat setter tile. The firing should
follow a specific firing profile, what causes the need of a programmable box kiln.
A typical profile shows a (slow) rising temperature (about 2-5°C per minute) up
to about 450°C with a dwell time of about one to two hours, where the organic
burnout (binder) takes place; then the temperature has to be rised up to 850 to
875°C with a dwell time of about 10 to 15 minutes. The hole firing cycle lasts
between three and eight hours (depends on the material; large / thick parts cause
the need of a modification of the firing profile).
Note: especially resistor pastes need to have defined firing conditions
(temperatures);Otherwise they vary enormous in value.

Postfiring:
Some materials need to be postfired; that means the paste is to be applied after
firing the tape and has to be fired again. The postfiring conditions depend on the
used material and vary in a wide range.
Note: especially resistor pastes need to have defined firing conditions
(temperatures); Otherwise they vary enormous in value.

Singulation:
If the fired parts have to be cut into smaller pieces or other shapes, there are three
different ways to realize. The first is to use a post fire dicing saw, which is a
common method and works very well for rectangular shapes; it holds tight outside
dimensional tolerances and allows high quality edges.The second possibility is to
use an ultrasonic cutter; the final part shows low tolerances and may have
unusually shapes. This process is very slow and expensive.The third method uses
a laser to cut the fired tape; the tolerances are tight, but the quality of the edges is
very bad.
Page 24 of 83
4.4
Microstrip
Common practise use in planar printed circuit boards (PCBs). When dealing with
actual RF circuits need to consider the higher frequencies behaviour of
conducting strips etches on the PCBs. The ground plane below carries conductors
traces help excess field leakage and reduces radiation loss. The use of PCBs
simplify the access to the active and passive devices on the board and reduces the
cost of the manufacturing process in the transmission lines. Below Fig 4.4.A
Fig 4.4.A
One major disadvantage of the single layered PCBs is that they have rather high
radiation loss and interference (CrossTalk) between nearby conductor traces. The
leakage depends on the relative dielectric constants in the electric field line
displays for Teflon epoxy ( r  2.55) and alumina ( r =10.0) dielectrics. Below
Figure 3.4.B is an example show how the electric field leakage as a function of
dielectric constant.
Figure 4.4.B
To achieve high board density of the field line of the components layout:
 Use substrates with high dielectric constants to minimum cross coupling.
 Use Multilayered techniques to achieve balanced circuit board designs where the
microstrip line is sandwiches between two ground plane, resulting 3 layer
configuration.
Page 25 of 83
 Configuration used for low impedance, high power application.
 Current and Voltage Flow confined two plates separated by dielectric medium.
4.4.1
Other types of MICROSTRIP
Several derivates of microstrip lines can be used as alternative structures for microstrip
filter implementations. These include suspended and inverted microstrip lines, multilayered microstrip,thin film microstrip and valley microstrip. In addition there are many
types of transmission lines that are interest of filter designs.
Suspended and inverted microstrip lines in Figure 4.4.1.A provides a higher Q (500~5000
for normal Conductor) than the conventional microstrip lines[6]. Normally they are
enclosed for filter applications.Although they can be used for realizing any types of filters,
the wide range of impedance values achievable makes them suitable for bandpass filter.
By using thin electric substrates of low dielectric constant, dielectric loss can be
minimized[7].
(a) Suspended microstrip line
(b) Inverted microstrip line
(c) Suspended or inverted
Microstrip line
Figure 4.4.1.A
Page 26 of 83
Typically there are 5 types of Microstrip filter:
4.4.2
1.
2.
3.
4.
5.
Low-Z / High-Z Lowpass
Lowpass using shunt stubs
Parallel-coupled bandpass
End-coupled bandpass
Branch-line bandpass
General features of microstrip filter are:
 Low Cost
 Easily integrated with active device
Except that they have:



Lossy, low Q, performance very poor
Low power handling
Spurious in free range
Page 27 of 83
4.5
Microstrip Resonator
Microwave resonant structures are extensively used in a variety of applications, such as
filters, oscillators and tuned amplifiers [6]. At low frequencies, resonant structure are
composed of the lumped elements. As the frequency of operation increases, lumped
elements in general cannot be used because the dimensions of lump resonator circuit
become comparable to the wavelength and this may cause energy loss by radiation. At
microwave frequencies, resonant structures using cavity resonators and microstrip
resonators are commonly employed. Since the project is primarily devoted to microstrip
filter circuits. Emphasis is placed on microstrip resonatorsonly. The choice of microstrip
resonators for filter design mainly attributed to easy of fabrication, low cost, lightweight,
reproducibility and greater flexibility in the design.
Its main drawback is its much higher insertion loss compared with the other types of
resonators such as cavity and dielectric resonators. The distributed line resonators shown
in Figure 3.4(c) and (d) may be termedquarter-wavelength resonators, since they are long,
 go / 4 where  g0 is the guidedwavelength at the fundamental resonant frequency f0. They
can also resonate at otherhigher frequencies when f  (2n – 1) f0 for n = 2, 3, · · · .
Another typical distributedline resonator is the half-wavelength resonator, as shown in
Figure 3.4(e), which is  go / 2 long at its fundamental resonant frequency, and can also
resonate at f  nf0 for n = 2, 3, · · · . It will be demonstrated later when we discuss filter
designsthat this type of line resonator can be shaped into many different configurations
for filter implementations, such as the open-loop resonator
[8].
(a)
(d)
(b)
(c)
(e)
FIGURE 3.5 Some typical microstrip resonators: (a) lumped-element resonator;
(b) quasi-lumped element resonator; (c)  go / 4 line resonator (shunt series resonance);
(d)  go / 4 line resonator (shun resonance); (e)  go / 2 line resonator.
Page 28 of 83
4.6
MicroStrip Transmission Line
Before digging into the microstrip topic let's spend a minute on transmission lines. see
Figure If you ignore parasiticresistances each section could be modeled as a small serial
inductance because any wire has a nonnull inductance and as a small capacitor between
the wire and the ground because the central wire is not far from the grounded shield.
These parasitic inductances and capacitances are roughly proportional to the length of the
small section so they can be noted L.dZ and C.dZ with L and C in henries per meter and
farads per meter. Therefore the wire can be approximated as a serially connected set of
identical L.dZ/C.dZ networks. If we apply a voltage on one end of the cable some current
will flow untilall capacitors are charged. If we are well rich and have an infinite length of
cable this current will flow forever. And if we apply an AC input you will get a given
impedance. This impedance is what is called the cable‘s characteristic impedance. In fact
it can be easily demonstrated that this characteristic impedance is simply the square root
Imagine you have a piece of coaxial cable divided into a large number of small sections
each of length dZof L/C. Just remember that the characteristic impedance of the cable
increases with L and decreases with C.
Transmission line can be modeled as a succession of small L/C networks. The
mathematical relationship between the L and C parameters and the characteristic
impedance of the line is simple to apply and slightly more complex to demonstrate.
Various forms of planar transmission lines have been developed for use in MIC. The
stripline, microstrip line, slot line and coplanar waveguide are some representative
planar transmission lines. Microstrip line is one of the most popular types of planar
transmission lines that will be described here. The geometry of a microstrip line is
shown in Fig3 .5a. A conducting strip (microstrip line) with a width W and a thickness
t is on top of a dielectric substrate that has a dielectric constant εr and a thickness h.
The bottom of the substrate is a conducting ground plane.
Page 29 of 83
Fig 3.6 (a) Geometry of
a microstrip transmission line
The microstrip line is an inhomogeneous transmission line. The field between the
strip and the ground plane are not contained entirely in the substrate but extend within
the two media namely, the air above and the dielectric below. Therefore, the mode
propagating along the microstrip is not purely transverse electromagnetic (TEM) but
quasi-TEM. Extensive literature dealing with analytical and numerical solutions of
this medium exists. Many simple closed-form empirical formulations have been
reported .For fast approximation of the microstrip characteristic impedance, we
considered the effect of conducting strip thickness t=0 in the calculation.
How do we control the characteristic impedance of a microstrip track? Usually with
the only parameter that we can easily manage on your LineCal tool track width
synthesize method and equation in 3.52. Intuitively if the track is wider the capacitance
between the track and the ground plane will increase and the characteristic impedance
will decrease. If the track is thinner its inductance and its characteristic impedance will
increase too. So there should be a given track width that corresponds exactly to 50 Ω at
least for a given PCB technology. This width is dependent on the PCB substrate FR4 is
the most common through its dielectric constant and the PCB thickness 1.6 mm or 0.8
mm for double-sided designs and slightly on the copper thickness which is 35 μm most of
the time. and the usual Roughly a 50-Ω track corresponds to a 3-mm wide track on a
standard 1.6-mm thick PCB and to 1.5 mm on a 0.8-mm PCB. For RF projects simply
because the tracks have a more manageable width. In summary whenever we design a
low frequency project we must always use tracks with the width for proper impedance
matching with a full ground plane on the opposite layer. The only exception is when the
length of the track is short compared to the signal‘s wave length e.g. a couple of
millimeters as in case impedance matching may be neglected.
Page 30 of 83
4.7
Coupled Microstrip lines
Coupled microstrip lines are widely use for implementing microstrip filters and
directional couplers [9]. Figure 4.7.A shows the cross section of a pair of coupled
microstrip lines. The two microstrip lines of width w are placed side by side with a
separation s on a dielectric substrate above a ground plane. The microstrip lines can
be arranged in parallel or edge-coupled configuration. This coupled line structure
supports two quasi-TEM modes. They are the even and odd-mode excitations. Figure
4.7.B illustrates the field distribution for the even and odd-modes on coupled microstrip
lines [9]. In the even-mode excitation, both microstrip conductors are of the same
potential and on which the same currents exist. The odd-mode excitation corresponds
to the conductors being at opposite potential. Thus the currents on the two conductors
are equal in amplitude but of opposite sign. The even and odd modes have different
characteristic impedances. Their values become equal when the separation between
the conductors is very large, that is the lines are uncoupled. Because coupled
microstrip lines are not pure TEM modes, the velocities of propagation of the two
modes are unequal. The different in phase velocity result in the microstrip coupled
filter having an asymmetrical passband response, deteriorating the upper stopband
performance and moves the second passband towards the center frequency [10]. To
overcome this problem, capacitive compensation of phase velocity in parallel
microstrip filters has been employed.
Figure 4.7.A: Cross section of a pair of coupled microstrip lines
Figure 4.7.B: The field distribution for the even and odd modes on coupled microstrip
line
Page 31 of 83
In the static approach, the fundamental mode of wave propagation in a microstrip is
assumed to be pure TEM. The characteristic impedances and the effective dielectric
constants of the two modes can characterize the coupled microstrip lines. Figure 4.7.C
shows the capacitances representation of symmetrical coupled lines. Cp denotes the
parallel plate capcitance between the conductor strip and the ground plane. Cm
denotes the coupling capacitance between the two conductors. By dividing the circuit
along the symmetry axis as shown in Figure 4.7.D, the capacitance Cm can be divided
into a series circuit of two capacitances, 2Cm.
Figure 3.7.C
Figure 3.7.D
In the even-mode excitation, the symmetry plane PP' as shown in Figure 4.7.D acts as
magnetic wall (open circuit). The determination of the even-mode capacitance
reduces to finding the capacitance of either line with the plane of symmetry PP' by a
magnetic wall as shown in Figure 4.7.E. This results in a great simplification of the
problem.
Similarly, in the odd-mode excitation, the symmetry plane behaves as an electric wall
(short circuit). The determination of the odd-mode capacitance reduces to finding the
capacitance of either line by replacing the plane of symmetry by an electric wall as
shown in Figure 4.7.F.
Figure 3.7.E
Figure 3.7.F
Page 32 of 83
The even and odd mode capacitances Ce and Co are given by:
Ce = Cp
Co = Cp +2Cm
The even and odd mode characteristic impedances Zce and Zco can be obtained from
the capacitances.
Z ce 
Z co 
1
c C e C oe
1
c C 0 C 00
where Coe and Coo are the even and odd mode capacitance for the coupled microstrip
line configuration with air as dielectric. The effective dielectric constant εree and εreo
for even and odd mode due to the unequal phase velocities of the two modes are
 ree 
Ce
C oe
 re0 
C0
C 00
An excitation of symmetric coupled line can be considered as the superposition of
even and odd modes. The understanding of basic concepts for microstrip lines and
coupled microstrip lines are useful for design of microstrip resonator filters.
4.8
FR4 Process Methodology
Electroplating a tin/lead alloy circuit pattern over the copper foil as an etch resist is a very
common fabrication method. The subtractive method (chemical etch) of selectively
removing copper continues to be in wide use throughout the PCB industry. When
SMOBC boards are processed, the tin/lead is chemically stripped leaving only the copper
conductors and component attachment sites free of plating. Plasma may be used to
achieve etchback. Where appropriate, standard FR-4 desmear and/or etchback processing
can be used Copper coated with epoxy or polymer solder mask to prevent exposure
processes. Permanganate preconditioners (swellants) using non-aqueous solvents such as
NMP (N-Methyl Pyrolidone) have been used successfully to provide 2-point etchback.
Plating and/or coating options include alloys and chemistry.
Page 33 of 83
4.8.1
Plating Process Options




4.8.2
Hot Air Leveled Tin/Lead (HASL)
Electroplated Tin/Lead
Electroless Gold over Nickel
Electroplated Gold over Nickel
Tin/Lead Alloy Plating
With the hot air leveling method, tin lead is applied to the board after solder mask
application. Coated boards are cleaned, fluxed and dipped into molten solder and while
the alloy is still in a liquid state, excess material is blown off the contact surface leaving a
alloy coated surface. The HASL plating process is widly used and generally compatible
with reflow solder assembly processes however, inconsistent solder volume and flatness
may not be suitable for boards using fine pitch devices.
4.8.3
Ni/Au Electroless or Immersion Plating Process for Soldering
Electroless nickel/gold is applied over the exposed bare copper after solder mask coating
process. With this process, the fabricator will typically use the tin/lead plated circuit
pattern as an etch resist, strip the tin lead after etching as noted above but, instead of
applying solder alloy to the exposed attachment sites and holes, the boards are immersion
coated with the nickel/gold alloy.
4.8.4
Alternatives to Alloy Plating
Adding solder alloy to the board after solder mask application is costly and subjects the
substrate to extremely stressful conditions. With tin/lead coating for example, the board is
thrust into molten solder, extracted and blasted with air to remove excess tin/lead material.
Thermal shock can cause delamination of the substrate structure, damage to plated holes
and defects that may affect long term reliability. Nickel/Gold plating, although less
stressful, is not a technology that is available from all board fabricators. As an alternative
to plating, many companies have found success and an economic advantage as well as a
flat attachment surface with organic preservatives or pre-flux coatings over bare copper.
4.8.5
Process on Organic Solderability Preservative (OSP)
As a means of retarding oxide growth on the bare copper attachment sites and via/test
pads, a special preservative or inhibitor coating is applied to the board. Organic/nitrogen
coating materials such as Benzotriazole and Imidazole are developed to replace the alloy
finishes described and are available under trademark names from several sources.
Chemical inhibitors compounds are implent to the bare copper by dipping or spray coat.
Before implent the material, the copper surface is complled with void of all oxidation and
oil residue. A typical cleaning agent for copper surfaces is Alkaline and Nitric Acid. The
acid definitely acts as a mild etchant leaving a matte texture. The process flow chart
illustrated in Figure 4.8.5.A is an example of the steps necessary to assure that the bare
copper device attachment sites are protected from oxidation before the solder attachment
of surface mounted devices.
Page 34 of 83
Figure 4.8.5.A
OSP are utilization in the latest part of process in the fabrication of PC boards. Solder
mask, silk-screen legend and electrical testing should be complled before coating. The
chemical film coating is to be cleaving only to the exposed copper alloy and is
formulated to dissolve when the flux is energized during the solder process. Shelf life is
severley . To maximize the storage life of the coating, packaging should be sealed and
boards stored in a low humidity environment and one should avoid physical contact with
the device attachment sites.
4.8.6
Assembly Process Compatibility
The organic coated copper is compatible with most soldering processes and can decrease
defects attributed to the uneven surface typical of hot air solder leveled (HASL) boards.
 OSP Provides a Uniform Solder Paste Pattern
 Minimizes Skewing When Placing Fine Pitch Devices
 Improves Overall Solder Process Yield*
 Compatible With Most Soldering Technologies
* Solder process related defects on the higher density PC boards cannot be totally
eliminated however, when compared directly to HASL type boards, the OSP board will
typically have 15-20% fewer solder process related defects on fine pitch devices.
Page 35 of 83
4.8.7
Limited Shelf Life for OSP Coated Boards
Solderability testing should be performed on boards that have been stored for over six
months. If the solder quality is degraded because of a breakdown of the coating, the
material can be stripped in an alkaline solution and recoated without physical stress or
damage to the PC board structure. Other factors that will affect solderability of coated
boards is surface contamination caused by physical contact of the boards surface by
inspection personnel or assembly operators. Those handling OSP circuit boards should
pick up the board holding only the edges or use gloves because the oils typically present
on fingers and hands contain salts and acids that will easily degrade the coating material.
4.8.8
Benefits of Coated Surfaces




Attachment Surface is Flat and Uniform
Low Thermal Stress on Board
Storage Life is Good (but not unlimited)
Excellent Solder Process Yield
Each of the coating technologies have their advantages but assembly process complexity,
solder/flux material and cleaning methods will greatly influence the overall success of
the manufacturing quality and cost.
4.8.9
Concerns of Coated Boards




4.8.10
Deteriorates in High Humidity and Temperature\
Limited (6-12 month) Shelf Life
Physical Contact Will Degrade Coating
Exposed Copper Will Tarnish w/o Solder Coating
Advantage on FR-4-86 material for Microwave and RF applications
 FR4 is a sophisticated and well established substrate technology with low initial





and production costs.
Not suitable for high frequency application because of it losses.
Low tolerance in dielectric constant (RO3003) & electrical strength under both
dry & humid conditions. In addition, it has flame resistance of at least Class I in
accordance with NEMA test method 7.11
High TCE (close to Cu and Al)
Capable for multilayer modules with prepreg technology
Large circuit area possible >(20 x 20) inch sq
Page 36 of 83
4.8.11
ADS implementation
4.8.11.1 Calculate width & 50Ω impedance for LTCC & FR4
The width of the microstrip can be pre-determined by line cal synthesize method to
obtain 50Ω impedance. Since for a start we need to input all the parameter specification
including dielectric constant to fine tune the process. Attach below in Figure 4.8.11.1.A
for LTCC and Figure 4.8.11.1.B for FR-4.
Er=7.4, Mur=1.0,H=1060 m ,
Hu=3.9e+3.4mil, T=17 m , Cond=4.1e7,
Tan D=0.001, Freq=30GHz Zo=50Ω,
E_eff=180ºC.
W=1925.49 m approximate = 1930 m
Figure 4.8.11.1.A
Er=4.7, Mur=1.0,H=1600 m ,
Hu=3.9e+3.4mil, T=17 m ,
Cond=5.8e7, Tan D=0.02, Freq=1.5GHz,
Zo=50Ω, E_eff=180ºC
W=2887 m approximate = 2890 m
Figure 4.8.11.1.A
Page 37 of 83
4.8.12
Calculation Method
4.8.12.1
LTCC
W /h 1
W
1930

 1.82
h
1060
 value is greater than 1.
 re 
r  1
2

r  1 
h 
1  12

W


2
 0. 5
7.4  1
7.4  1 
1930 

1  12

2
2
1060 

 4.869
 0. 5
 re 
where  r is the delectric constant &  re is the effective dielectric constant of a
microstrip
 W
W

Zc 
  1.393  0.677 In   1.444 
 re  h
h

1
120  1930
 1930


 1.393  0.677 In 
 1.444 

4.869 1060
 1060

 50 
1
4.8.12.2 FR4
W /h 1
W
2900

 1.8125
h
1600
 value is  1.
 re 
r  1
2

r  1 
2
h
1  12 
W

 0 .5
4.7  1
4.7  1 
1600 

1  12

2
2 
2900 
 3.52
 0 .5
 re 
Page 38 of 83
 W
W

Zc 
  1.393  0.677 In   1.444 
h

 re  h
4.8.13
1
120   2900
 2900


 1.393  0.677 In 
 1.444 

 1600

3.52 1600
 50 
Determine the microstrip guided wavelength
1
Once the effective dielectric constant of a microstrip is determined, the guided
wavelength with fundamental resonant frequency is given by as shown below:
4.8.13.1 For LTCC
g 
0
f (GHz )  re
where 0 is the free space wavelength of operating frequency
g 
0
f (GHz )  re

3  10 8
30  10 9 4.869
3.5.3.1(a)
 453.189m
For half wavelength micro-strip:
l
g
2
 226.59m
4.8.13.2 For FR4
g 
0
f (GHz )  re

3  10 8
1.5  10 9 3.52
3.5.3.1(b)
 5681.81m
For half wavelength micro-strip:
l
g
2
 2840.905m
Page 39 of 83
5
FILTER IMPLENTATION IN ADS
5.1
Setting of substrate Parameters in LTCC
A prototype design was designed and mapped onto BPF using ADS simulation software.
The most difficult parts when we set the dielectric constant to 7.4 have to set the length
and the width of the microstrip lines to overlap the resonators. The passing criteria of the
S11 must be less than -10dB and the S22 must be as flat as possible.
Many experiments have been carried out. To achieve the passing criteria of the S11 &
S22, I have to play around the resonators length, width and overlapping. I have attached
how to set the ADS software and the design of the simulation result behind appendix .
Since both side of the resonator are symmetrical, I will only point out the changes.
Page 40 of 83
5.1.1
Set up of Montenum under ADS
Refer to Explanation on Chapter 5 and Appendix C.
Page 41 of 83
As we can see from the graph from the 10 simulation results at appendix, when
increasing the length not more than 1555μm, result become very stable but in the
meantime don’t forget about the overlapping it’s very critical. When the resonator began
to shift from (0~120)μm, I discovered that the S11 began to shift lower and lower up to 40dB.
Comparing of Fig 1, Fig 9 & Fig 10, all can achieve the specification given by tutor. But
the main point is that to achieve gratifying result, Fig 9 given the best result for this BPF
fractional bandwidth of 3%, return loss at -40.8dB , insertion loss at 3.12dB at centre
frequency 30.23GHz.
As I can conclude that the width and spacing of the lines determine the filter
characteristics, with narrow spacingbeing required for broad pass bands. Narrow pass
bands thus require larger spacing which results in less coupling between the elements and
thus increased loss. Other filtering structures are possible based on coupled line
arrangements where lowloss or narrow bandwidths are required.
Page 42 of 83
5.2
Setting of substrate Parameters in FR4
A prototype design for FR4 was designed and mapped onto BPF using ADS simulation
software.
The most difficult parts when we set the dielectric constant to 4.7 and the loss tangent of
0.02dB given by the manufacturer specification have to set the length and the width of
the microstrip lines to overlap the resonators. The passing criteria of the S11 must be less
than -10dB and the S22 must be as flat as possible.
After synthesis from LineCal, we need to pre-determined the width. As I say calculation
may not be so accurate so we need to fine tune. After fine tune, it came to meet the S11 &
S21 desired result. We also have to make sure the input and output ports need to set 50Ω
for impedance matching as shown in figure 4.2.d
Page 43 of 83
Figure 4.2.d
I also test out the most very basic of the microstrip attached behind the appendix to
to see whether the frequency will shifted more than 3GHz. From the result attached
result in figure 4.2.e, the best result simulation at point 3.
Page 44 of 83
Figure 4.2.e
Gap between the microstrip and resonator also play important part for
the S11 and S21 simulation. Refer to appendix for more simulation result. When the gap
reaches on point 5, S11 result getting -23.966dB and S21 result getting -3.166dB
As I say before even with LTCC, the width and spacing of the lines determine the filter
characteristics, with end gap spacing being required for broad pass bands. End Gap
coupled thus require larger spacing which results in less coupling between the elements
and thus increased loss. Other filtering structures are possible based on coupled line
arrangements where lowloss or narrow bandwidths are required.
Page 45 of 83
6
FABRICATION ON FR4 END GAP COUPLED
Before we send for fabrication, we need to give the supplier our gerber file. For the ADS itself
we export each layer of file send to the supplier as shown in Figure 6.C.
Note: Format Version should be tell to supplier because of their cad version may be different.
Figure 6.A.
Figure 6.B.
16.89mm
136mm
Figure 6.C
Page 46 of 83
6.1
Process of FR4 from supplier
Mentioned in 4.8.5
OSP are utilization in the latest part of process in the fabrication of PC boards. Solder
mask, silk-screen legend and electrical testing should be complled before coating. The
chemical film coating is to be cleaving only to the exposed copper alloy and is
formulated to dissolve when the flux is energized during the solder process. Shelf life is
severley . To maximize the storage life of the coating, packaging should be sealed and
boards stored in a low humidity environment and one should avoid physical contact with
the device attachment sites.
Page 47 of 83
6.2
Hardware Mounting 1 ( Initial Design)
After fabrication, we need to break away all sided PCB. Assemble all 4 sided PCB together with
screw and nuts. Solder 2 input and output ports with SMA Jack connector. But in the end, I
realize that when doing mounting all four PCB to the connector the 50 ohm impedance very
difficult to solder the trace in Figure 6.2.A. So I come out another assemble PCB design on
Figure 6.3.B
Break Away all 4 sided PCB.
Figure 6.2.A
Page 48 of 83
6.3
Hardware Mounting 2 ( Final Design)
Figure 6.3B shows the fabricated FR4 End Gap Coupled Band BPF of which size is
136 x 17 x 1.6mm. Openings were made to probe the CPW pads on the third layer for
direct measurement without any additional vertically connected vias. Because the FR4
board all conductors including transmission lines and resonators were designed
considering the shrinkage.
Figure 6.3.B
Page 49 of 83
7
HARDWARE MEASUREMENT
Hardware measurement is performed firstly in SIM LABORATORY RM 5.0.6 with the
following measuring equipments and tools:
1) Agilent VNA Network Analyzer E5062A (Figure 7.A)
2) 2m BNC cables x 2 (Figure 7.B)
3) SMB Female Jack Adapter (Figure 7.C)
(Figure 7.A)
7.1
(Figure 7.B)
(Figure 7.C)
Hardware Measurement Set Up
The following steps are carried out in the process of set up the equipment and measuring
the filter.
1. Turn on the VNA Network Analyzer E5062A.
2. Connect BNC cable to input to Port 1 and the output to Port 2.
3. Self calibration on the equipment, which includes cal “Short” and “Open”.
4. Set the VNA frequency range from 1GHz to 3GHz.
5. Connect the filter design with the SMB Female Jack connector from one end of
Port 1 and the other end of Port 2.
6. Measure filters response of S11 & S21.
7. Repeat Step 1 to Step 5 with OSP coating.
8. Save it to the disk.
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7.1.1
Measurement Result
Without Solderability Preservatives
Figure 7.1.1.A
Figure 7.1.1.B
With Solderability Preservatives
Figure 7.1.1.C
Figure 7.1.1.D
Parameter
Measure
Measured with OSP
Measured without OSP
Centre
Frequency (fo)
1.494GHz
1.895GHz
1.953GHz
Lower Band
Edge (fL)
1.426GHz
1.801GHz
1.882GHz
Upper Band
Edge (fH)
1.550GHz
1.989GHz
2.025GHz
Fractional
Bandwidth
8.30%
9.90%
7.73%
Min insertion
loss
-3.148dB
-10.101dB
-17.84dB
-24.21dB
-22.577dB
-14.528dB
Max return loss
Figure 7.1.1.E
Page 51 of 83
7.1.2
Summary of the end-gap coupled multilayered FR4 BPF
The s-parameters of the BPF are measured and the insertion loss and the return loss are
plotted in Fig.7.1.1.E with the EM and measuring simulation results. The measured data
include the effect of microstrip feedthroughs. The minimum insertion loss of the BPF is
10.1dB at 1.8 GHz, and the fractional bandwidth is 9.9%. The measured insertion loss is
about 7 dB lower than that of simulated value, and the center frequency is also shifted
from 1.4 GHz to 1.9 GHz. We suppose that the shift of the center frequency and the loss
are mainly due to the oxidation without any OSP coating and the simulated and measured
result vary.
The EMsimulation and at 1.5 GHz in the measurement whichwas not expected in the first
trial ideal series capacitor model. The first trial circuit was optimized in the final layout to
an electromagnetic structure of which coupling capacitances between the resonators in
the circuit model, and which accounts the peaking in both EM simulation and
measurement. in Figure 7.1.1.E
7.1.3
Conclusion
The final design had a reasonable on return loss on (S11) return loss.but insertion loss
more than 10dB after fabrication. However it does not meet the expectation from
simulated result. One root cause maybe, it should be mount on test jig as I mentioned
before previous chapter to get more grounding and stable frequency for the improved
version.I have to fabricated a few more to see any changes or drifted frequency.
Another root cause maybe cause by tangent loss and material use in microstrip line.
Every PCB the specification given by supplier the loss vary so it better to get a
multilayered in one PCB because I need to adjust all the 4 layered PCBs together, the
coupling may not be able to archieve what I suppose to get the desired result.
Connector issue also plays another apart. I using the 75 ohms SMB Jack because of the
combination of 4 PCBs so that it can be soldered on the trace. It should be chosen on 50
ohm SMA female connector and consideration of thickness PCBs.
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8
GANTT CHART
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9
APPENDIX A
[1] C. Q. Scrantom, “Where we are and where we’re going-II,” in IEEE
MTT-S IMS Dig., 1999, pp. 193–200.
[2] S. Pinel, S. Shakraborty, M. Roellig, R. Kunze, S. Mandal, H. Liang,
C-H. Lee, R. Li, K. Lim, G. White, M. Tentzeris, and J. Laskar, “3D
integrated LTCC module using _ BGA technology for compact C-band
RF front-end module,” in IEEE MTT-S IMS Dig., 2002, pp. 1553–1556.
[3] C.-H. Lee, S. Chakraborty, S. Yoo, D. Heo, and L. Laskar, “Broadband
highly integrated LTCC front-end module for IEEE 802.11a WLAN applications,”
in IEEE MTT-S IMS Dig., 2002, pp. 1045–1048.
[4] C.-K. C. Tzuang, Y.-C. Chiang, and S. Su, “Design of a quasiplanar
broadside end-coupled bandpass filter,” in IEEE MTT-S IMS Dig., 1990,
pp. 407–410.
[5] G. L. Matthaei, L. Young, and E. M. T. Jones, Microwave Filters,
Impedance-Matching Networks, and Coupling Structures. New York:
McGraw-Hill, 1964. Authorized licensed
[6] K. C. Gupta, R. Garg, I. Bahl, and P. Bhartis, Microstrip Lines and Slotlines, Second
Edition, Artech House, Boston, 1996.
[7] J.-S. Hong, J.-M. Shi, and L. Sun, “Exact computation of generalized scattering
matrix of suspended microstrip step discontinuities,” Electronics Letters, 25, 5, 1989,
335–336.
[8] J.-S. Hong and M. J. Lancaster, “Couplings of microstrip square open-loop resonators
for cross-coupled planar microwave filters,” IEEE Trans., MTT-44, Nov. 1996,
2099–2109.
[9] R. Mongia, I. J. Bahl and P. Bhartia, RF and Microwave Coupled-line Circuits,
Artech House, 1999.
[10] J. Bahl, " Capacitively Compensated High-Performance Parallel Coupled
Microstrip Filters," IEEE MTT-S Int. Microwave Symp. Dig., pp. 679-682,
Page 54 of 83
9.1
Website
http://www.rfglobalnet.com/article.mvc/Filter-Design-Considerations- 0002
http://www.rfglobalnet.com/article.mvc/The-ADS-Filter-Design-Guide-0001
http://www.syfer.com/doc_docs//an0023_LTCC_Filters.pdf
http://www.ltcc.de/en/software.php
http://amsacta.cib.unibo.it/423/1/JGM1_Massiot.pdf
http://www.ltcc-consulting.com/LTCC_technology
http://www.home.agilent.com/agilent/product.jspx?cc=US&lc=eng&ckey=1297113
&nid=-34346.0.00&id=1297113
http://www.plextek.com/papers/nordic.pdf
http://en.wikipedia.org/wiki/Low_temperature_co-fired_ceramic
http://www.ansoft.com/partnersindesign/16.pdf
http://cc.ee.ntu.edu.tw/~jfkiang/electromagnetic%20applications/ch8_2004.pdf
http://cc.ee.ntu.edu.tw/~jfkiang/electromagnetic%20applications/ch8_2005.pdf
http://www.ursi.org/Proceedings/ProcGA05/pdf/D03.10(0626).pdf
http://hehr-sachsen.de/files/3d_module_paper.pdf
http://www.eecs.stut.edu.tw/~test3/ieet/word/961121.pdf
http://books.google.com.sg/books?id=uU2rnznM2kC&pg=PA5&lpg=PA5&dq=LTCC+filter+on+ADS&source=bl&ots=lou
QUvQvbQ&sig=wenGPm2Rkbtzv68fi1GXXYOWtA&hl=en&ei=MA6US4PuKcq2rAfI49jFCw&s
a=X&oi=book_result&ct=result&resnum=10&ved=0CCMQ6AEwCTgU#v=onep
age&q=&f=false
http://www.ltcc.de/en/home.php
http://en.wikipedia.org/wiki/Printed_circuit_board
Page 55 of 83
http://www.edaboard.com/thread73580.html
http://www.trianglecircuits.com/lead-free-finishes.html
http://www.youtube.com/watch?v=JDKzQeWhAJM&feature=related
http://www.ltcc-consulting.com/LTCC_technology
http://chemandy.com/calculators/microstrip_transmission_line_calculator.htm
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9.2
Appendix B
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9.3
Appendix C: Software simulation for FR-4
Step 1: (MicroStrip P1)
Step 2 : (Microstrip P1 & P2 with Resonator R1)
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Step 3: (Microstrip P1, P2 & P3 with resonator R1)
Step 4 :
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9.3.1
Appendix D: Software simulation for FR-4
Test 1: (107 micronmeter)
Gap between Microstrip & Resonator
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Test 2: (207 micronmeter)
Overlapping Gap between Microstrip & Resonator
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Test 3: (407 micronmeter)
Overlapping Gap between Microstrip & Resonator
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Test 4: (807 micronmeter)
Overlapping Gap between Microstrip & Resonator
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Test 5: (679 micronmeter)
Overlapping Gap between Microstrip & Resonator
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9.3.2
Appendix E: Software simulation for FR-4
Gap between Microstrip & Resonator
Test 1: (585 micronmeter)
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Test 2 : : (2000 micronmeter)
Gap between Microstrip & Resonator
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Test 3: (3000 micronmeter)
Gap between Microstrip & Resonator
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Test 4: (4000 micronmeter)
Gap between Microstrip & Resonator
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Test 5: (5085 micronmeter)
Gap between Microstrip & Resonator
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Test 6: (4085 micronmeter)
Gap between Microstrip & Resonator
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9.4
Appendix F: Meetings Logs
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