GUC (Dr. Hany Hammad)
9/5/2016
Microwave Technology
(COMM 903)
© Dr. Hany Hammad, German University in Cairo
Contents
• Introduction:
– Course contents.
– Assessment.
– References.
• Microwave Sources.
• Transistor Model Extraction.
• Signal flow graphs.
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
1
GUC (Dr. Hany Hammad)
9/5/2016
Course Contents
• Active Microwave & RF Circuits Analysis & Design
– Noise, Microwave Sources, Amplifiers, Mixers & Oscillators.
• Metamaterials and Transmission Lines
– Basic properties, Transmission Line Implementations and
Applications.
© Dr. Hany Hammad, German University in Cairo
Teaching Assistant (Tutorials)
 Engs. Randa El Khosht
Teaching Assistant (Advanced Comm. Lab.)
 Eng. Yasmine Abdella
References
 David M. Pozar, “Microwave Engineering”, 3rd Edition, Wiley.
 Lecture Notes
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
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GUC (Dr. Hany Hammad)
9/5/2016
Assessment
15
Quizzes (2-3)
5
Tutorial Assignments
Project
10
Mid Term Examination
25
Final Examination
45
100
Total
© Dr. Hany Hammad, German University in Cairo
Microwave Sources
Solid State Sources
Low Power &
Low Frequencies
Sources
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
Microwave Tubes
High Power &/or
high frequencies Sources
Microwave Engineering, 3rd Edition
by David M. Pozar
Copyright © 2004 John Wiley & Sons
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GUC (Dr. Hany Hammad)
9/5/2016
Microwave Tubes
Types of Microwave Tubes:
– Klystron
– TWT (Traveling Wave Tubes)
• Helix TWT.
• Coupled cavity TWT.
– Magnetron.
– Gyroton.
– Gridded Tube.
– CFA (crossed field amplifiers)
© Dr. Hany Hammad, German University in Cairo
Solid State Sources
• Advantages:
– Small Size.
– Low Cost.
– Compatibility with microwave integrated circuits.
• Disadvantages:
– Low power.
– Low frequencies.
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
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GUC (Dr. Hany Hammad)
9/5/2016
Solid State Sources
• Can be categorized as:
– Two terminal devices
• Ex.: Diodes.
– Three terminal devices
• Ex.: Transistor oscillators.
© Dr. Hany Hammad, German University in Cairo
Diode Sources
• Most common diode sources:
– Gunn diode.
– IMPATT diode.
• Directly convert DC bias to RF power in the frequency range of 2
to 100 GHz.
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
5
GUC (Dr. Hany Hammad)
9/5/2016
Gunn Diode
• Even though everyone uses
this term! It’s more accurate
name is a “Transferred
Electron Device” (TED). Why
isn't it a "real" diode?
Because it only uses N-type
semiconductor.
• Gunn diodes have been
around since John Gunn
discovered that bulk N-type
GaAs can be made to have a
negative resistance effect.
• Three regions exist: two of
them are heavily N-doped
on each terminal, with a thin
layer
of
lightly
doped
material in between.
© Dr. Hany Hammad, German University in Cairo
Broadband Microwave Amplifiers
by Bal S. Virdee, Avtar S. Virdee, & Ben Y. Banyamin
Copyright © 2004 Artech House
Gunn Diode
Two Gunn diode sources.
The unit on the left is a mechanically tunable E-band source, while the
unit on the right is a varactor-tuned V-band source.
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
Microwave Engineering, 3rd Edition
by David M. Pozar
Copyright © 2004 John Wiley & Sons
6
GUC (Dr. Hany Hammad)
9/5/2016
FET
© Dr. Hany Hammad, German University in Cairo
Small Signal Models
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
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GUC (Dr. Hany Hammad)
9/5/2016
The GaAs MESFET Structure
Cross sectional view of the GaAs MESFET structure shows the depletion
region below the gate
The contact of the gate is made of metal-semiconductor Schottky
Contact rather than a metal-oxide-semiconductor (MOS) structure,
which is used in the MOSFET device.
This approach minimizes the device’s gate to source capacitance,
which otherwise would degrade the high-frequency gain performance.
© Dr. Hany Hammad, German University in Cairo
Broadband Microwave Amplifiers
by Bal S. Virdee, Avtar S. Virdee, & Ben Y. Banyamin
Copyright © 2004 Artech House
The GaAs MESFET
w s vsat
gm 
hd
fT 
gm
2C gs
gm= intrinsic device transconductance
hd= depletion-layer depth
w = gate width
s= semiconductor dielectric constant
vsat= saturated carrier velocity
fT = Unity-current-gain frequency
Cgs= gate to source capacitance
At frequencies above fT the current passing through the Cgs is greater
than that produced by the transconductance, therefore, fT represents a
fundamental high-frequency limit.
C gs 
fT 
w s l g
hd
vsat
2l g
For optimum high-frequency performance, the device
designer must either increase the saturated carrier
velocity or decrease the gate length.
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
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9/5/2016
Device Characterization and Modeling
• Small signal model Intrinsic & Extrinsic elements is determined
using the hot and cold deembedded S-parameters measurements.
• Large Signal model is determined by using the semi-empirical
method, and it uses the measured pulsed dc I-V data of the
device and no assumptions are made relating to the physical
operation of the device itself.
• One key issue in S-parameters measurements is the accurate
calibration of the network analyzer. The calibration of the
instrument should remove unwanted and repeatable information,
such as the effects of non-ideal transmission lines, connectors,
and circuit parasitic.
© Dr. Hany Hammad, German University in Cairo
Small-signal device modeling procedure
Cold
Vds = 0 V
Vgs = -3 V (pinch off)
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
Broadband Microwave Amplifiers
by Bal S. Virdee, Avtar S. Virdee, & Ben Y. Banyamin
Copyright © 2004 Artech House
9
GUC (Dr. Hany Hammad)
9/5/2016
Hot S-parameters Extraction
Cdc = diople layer capacitance
Rg & Rd represent the device’s gate and drain resistance.
Rs & Ls are the source resistance and inductance.
The extrinsic parameters Cgp, Cdp, Lg, Ld, Rg, Rs and Rd.
The gate and drain bond-pad capacitance (Cpg and Cpd) in the modeling
process.
© Dr. Hany Hammad, German University in Cairo
Broadband Microwave Amplifiers
by Bal S. Virdee, Avtar S. Virdee, & Ben Y. Banyamin
Copyright © 2004 Artech House
Cold S-parameters Extraction
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
Broadband Microwave Amplifiers
by Bal S. Virdee, Avtar S. Virdee, & Ben Y. Banyamin
Copyright © 2004 Artech House
10
GUC (Dr. Hany Hammad)
9/5/2016
Cold S-parameters Extraction

Z c11  Rg  Rs  j  Lg  Ls   1 Cab
Zc12  Z c 21  Rs  jLs  1 Cb 

Z c 22  Rd  Rs  jLd  Ls   1 Cbc 
1
Cab
 Ca1  Cb1
Cbc1  Cb1  Cc1
Rg  ReZ c11  Z c12 
Rs  ReZ c12 
Rd  ReZ c 22  Z c12 
 ImZ c11    2 Lg  Ls   1 Cab
 ImZ c12    2 Ls  1 Cb
 ImZ c 22    2 Ld  Ls   1 Cbc
© Dr. Hany Hammad, German University in Cairo
Hot S-parameters Extraction
+
v gs
g m  g mo e  j 


1

Y11  jC gd  
 R  1 jC 
gs 
 i
Y12   jCgd
Y21  g mo e j  1  jRi Cgs   jCgd
Y22 
1
 j Cds  C gd 
Rds
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
Broadband Microwave Amplifiers
by Bal S. Virdee, Avtar S. Virdee, & Ben Y. Banyamin
Copyright © 2004 Artech House
11
GUC (Dr. Hany Hammad)
9/5/2016
Model Extraction
Cgd   ImY12  
ImY11   C gd 
ReY11 2

1 


 ImY11   C gd
C gs 





2



Ri  ReY11  ImY11   C gd  ReY11 
ReY
g mo 
21
2
2

2  Im(Y11)  Cgd 2 1   2Cgs2 Ri2 
g m  g mo e  j 
  1 /  sin 1 Cgd  ImY21   ReY21 Cgs Ri  g mo 


Cds  ImY22   Cgd 
Rds  1 ReY22 
© Dr. Hany Hammad, German University in Cairo
S-parameters files
© Dr. Hany Hammad, German University in Cairo
COMM (903) Lecture # 1
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GUC (Dr. Hany Hammad)
9/5/2016
Extraction Steps
• Measure the S-parameters and save as .s2p file.
• Load file into Matlab (load file name.s2p)
• Convert the s2p to y-parameters using the equations (or using
s2y command in matlab.
© Dr. Hany Hammad, German University in Cairo
MESFET Model Extraction Project
I1
C gd
I2
Gate
Drain
+
v gs C gs
V1
-
g m vgs
Rds
Cds
V2
Ri
Source
I1  Y11V1  Y12V2
I 2  Y21V1  Y22V2
COMM (903) Lecture # 1
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GUC (Dr. Hany Hammad)
9/5/2016
Finding Y11 & Y21
In case of V2=0
C gd
I1
I2
Gate
Drain
+
v gs C gs
-
V1
g m vgs
Rds
Cds
V2=0
Ri
Source
C gd
I1
Gate
I2
Drain
+
v gs C gs
V1
-
g m vgs
V2=0
Ri
Source
Finding Y11 & Y21
I1
Gate
 V1  jCgd 
I2
+
v gs C gs
V1
-
g m vgs
V2=0
Ri
Source
I 2  V1  jCgd   g mvgs
vgs 
V1 1 jC gs 
Ri  1 jC gs
I 2  V1  jCgd  
COMM (903) Lecture # 1

Y21 
V1
1  jC gs Ri
g mV1
1  jC gs Ri
gm
I2

 jC gd
V1 V 0 1  jC gs Ri
2
Y11 


I1
1

 jC gd  


V1 V 0
R

1
j

C
gs 
 i
2
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GUC (Dr. Hany Hammad)
9/5/2016
Finding Y11 & Y21
 jC gs 
 jC gs   1  jC gs Ri 
  jC gd  


Y11  jC gd  
 1  jC R 
 1  jC R   1  jC R 
gs i 
gs i  
gs i 


2
 jC gs   2C gs
Ri 


Y11  jC gd 
 1   2C 2 R 2 
gs
i


Y11 
 2Cgs2 Ri
D
 C gs

 j 
 C gd 
 D

2
D  1   2Cgs
Ri2
Finding Y11 & Y21
I1
Gate
I2
C gd
Drain
+
v gs C gs
V1
-
g m vgs
V2
Rds
Cds
Ri
Source
Gate
I1
I2
C gd
Drain
V2
V1
Rds
Y22 
Cds
I2
V2
Y12 

V1 0
I1
V2
1
 j Cds  C gd 
Rds
  jC gd
V1 0
Source
COMM (903) Lecture # 1
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GUC (Dr. Hany Hammad)
9/5/2016
Extracted Model Parameters
NE321000
Vds = 2 V Id = 10 mA
Cgd  2.2548 1014 F  0.02548 pF
Cgs  1.1782 1013 F  0.11782 pF
Ri  7.3838
g m  0.0664 S
  3.5229 1013 sec  0.35229 p sec
Cds  4.7753 1014 F  0.47753 pF
Rds  198.924
Results Y11 (Measured Vs Calculated from extracted Model)
-3
4
x 10
3.5
3
 e(Y 11) (S)
2.5
2
1.5
0.03
1
0.025
0.5
0.02
Measured
Calculated
0
5
10
15
freq. (GHz)
20
25
30
 m(Y11) (S)
0
-0.5
0.015
0.01
0.005
Measured
Calculated
0
COMM (903) Lecture # 1
0
5
10
15
freq. (GHz)
20
25
30
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GUC (Dr. Hany Hammad)
9/5/2016
Results Y12 (Measured Vs Calculated from extracted Model)
-4
0.5
x 10
0
 e(Y 12) (S)
-0.5
-1
-3
-1.5
0
x 10
-0.5
-2
-1
-2.5
-3
0
5
10
15
freq. (GHz)
20
25
30
 m(Y12) (S)
-1.5
Measured
Calculated
-2
-2.5
-3
-3.5
-4
-4.5
-5
Measured
Calculated
0
5
10
15
freq. (GHz)
20
25
30
Results Y21 (Measured Vs Calculated from extracted Model)
0.074
0.072
 e(Y 21) (S)
0.07
0.068
0.066
0
0.064
0.062
0.058
Measured
Calculated
0
5
10
15
freq. (GHz)
20
25
30
 m(Y21) (S)
-0.005
0.06
-0.01
-0.015
-0.02
Measured
Calculated
-0.025
COMM (903) Lecture # 1
0
5
10
15
freq. (GHz)
20
25
30
17
GUC (Dr. Hany Hammad)
9/5/2016
Results Y22 (Measured Vs Calculated from extracted Model)
-3
5.3
x 10
5.2
 (Y22) (S)
5.1
5
0.014
4.9
0.012
4.8
4.7
0
5
10
15
freq. (GHz)
20
25
30
 m(Y22) (S)
0.01
Measured
Calculated
0.008
0.006
0.004
0.002
Measured
Calculated
0
COMM (903) Lecture # 1
0
5
10
15
freq. (GHz)
20
25
30
18