E&M/Communications
Applications
Aly E Fathy
Outline
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The microwave band
Non-communication applications
Communication Applications
Breakthroughs
Various Areas of Research at UT and other
Research Centers
• Courses
Microwaves
Frequency
Wavelength l
Long waves
30-300 kHz
10-1 km
Medium waves (MW)
300-3000 kHz
1000-100 m
Short waves (SW)
3-30 MHz
100-10 m
Very high frequency (VHF) waves
30-300 MHz
10-1 m
Microwaves
0.3-30 GHz*
100-1 cm
Millimeter waves
30-300 GHz
10-1 mm
Submillimeter waves
300-3000 GHz
1-0.1 mm
Infrared (including far-infrared)
300-416,000 GHz
* 1 GHz = 1 gigahertz = 10 Hertz or cycles per second,
+ 1 mm = 10-6 m.
104-0.72 mm
Non-Communication Application
Industrial Microwave Furnace
Modular Unit
Waveguide
Inert Environment
Crucible
Insulation
Mold Core
Mold
Free Space Communication
Attenuation of the Atmosphere at Various
Wavelengths
60
40
20
Why Microwaves
Radio equipments are classified under VHF, UHF & Microwaves.
VHF and UHF radios used when few circuits are needed and
narrow bandwidth.
Earlier equipments were large in size and use Analog Technology.
Recently Digital Radio with better efficiency is being used.
A Century of Antennas-- from Hertz to Hand-Held
Very large array of 27 steerable parabolic dish
Antennas
25 meter diameter, operating at ~ cm wavelength
To listen to signals transmitted billions of year away
24 GPS Antennas, medium earth orbits-MEO
Operating at 20 cm wavelength
Uses helix antennas, at 20,000 km
Hand-held cell-phones
Operating at 30 cm wavelength
Microwave Use
• Lower
bands are already occupied
• Now we have better electronics, and modulation schemes
Advantages of Microwave Utilization:
• Antennas are more directive—better beam control.
• Wider operating bandwidth.
• Smaller size elements
Microwave Systems
Microwave communication is line of sight radio communication
For directive antennas, or broadcasting with omi-directional antennas
Radio Transmission: the speech signals are converted to EM
Power is transmitted in space towards destination
EM waves are intercepted by receiving antennas and signal
power is collected
Types of Antennas
Antennas used can be:
• Omni-directional-in this case radio power is transmitted
Uniformly in all directions
Such type of antenna are preferred where uniform coverage
is desired such as in cellular systems.
• Directional: in case of UHF communication.
• Highly directional: in case of microwave communications,
microwave signals are transmitted in very narrow beam.
Normally 3 M Diameter Antenna at 2 GHz BW has half power
of about 3.4 degrees beam width.
Coverage
Applications:
Radio Communications
Radio Communication is in use since
early 30’s.
First was used for broadcasting then
commercial communication.
Radio used for long distance
telephone service.
Many phone lines are connected to an
Exchange, and many exchanges to a
tower
Cellular Communication
For providing cellular communication a number of antennas at a
particular height are installed around a circular platform
DBS Antennas
DBS-History
Current Solutions for US DBS
Broadside Patch Array Antennas
Complete Mechanical Steering
High Fabrication Cost. >12inch
Phased Array Antennas ~6inch
COST
Proposed Solution
Reflector Antennas for
Stationary Reception
Complete Mechanical Steering with limited
range (due to beam tilt)
SIW, Low Fabrication Cost
Low Profile Reflector Antennas
Complete Mechanical Steering
Low Fabrication Cost. ~12 inch
Mobility
Research Progress
12*64 Elements Slotted SIW Full Array
12x16 Elements SIW Sub-Array
Directivity
13 x 48
Elements Full
Array
13x32 Elements SIW Array With
Folded Feed Network
13 x 6 elements Sub-Array
12 Elements Slotted SIW Array
Efficiency
13 Elements Slotted Waveguide
Antennas for Mobile Systems
Why Do we need Reconfigurable
Antennas?
• Limited Space, and Volume
• Trend to further miniaturization
Difficulty to attain Directivity
G=4pA/l2, G = -18.5 dB/cm2 @1 GHz
Very Compact
(you add 3dB when you double the Area)
(you add 6 dB when you double the Frequency)
•Strong Antenna Interference due to Proximity
• More Services means more antennas
• Many are not used in same time.
Tiny
Multifunction
Does it all
Antenna Alternatives for Multi-Radio Application
Radio 1
Radio 2
Multiple
Radios
Ant. Gain
Broad Band Antenna
Radio 3
Frequency
• Covers all bands of interest, Good for sim-ops
Radio n
Ant. Gain
Reconfigurable Antenna
Frequency
• Very good noise immunity, high Flexibility
• Requires switches, Poor for true sim-ops


Ant. Gain
• Higher Noise , Non Uniformity in Ant. Gain


Multi-Band Antenna
Frequency
• Covers few bands of interest, OOB noise supp.
• Poor iso. between radios, stringent filter spec.


Mini-Nested Patches
Reconfigurable Multiband
2nd
Band
1st Band
802.11b/g/n
802.11a
0
Return Loss (dB)
Retrun Loss (dB)
0
2nd Band
DCS/PCS/IMT2000
-5
-10
-15
1st Band
GSM850/900
-20
Meas. w/Cable
CST MWS Simu.
Meas. Cable Loss
-25
0.5
1.0
1.5
-5
-10
-15
-20
CST MWS Simu.
Meas. w/Cable
Meas. Cable Loss
-25
2.0
Frequency (GHz)
2.5
2
3
4
Frequency (GHz)
5
6
Research Progress
42mm
11m
m
Switch
Locations
50cm coaxial
cable
RF blocking resistor
DC
Feeds
“Maze”
Reconfigurable
Fractal Loop Antenna
MEMS
Reconfigurable Multi-band branched
Monopole Antenna
Switches
“mini-Maze”
Reconfigurable Bent
Monopole Antenna
with MEMS switch
Reconfigurable Multi-band Twin PIFA
Antenna with PIN diode switch
90mm
10mm
p-i-n diodes
50cm coaxial cable
Ground
Power Amplifiers and Combiners
THz- BACKGROUND
• The detection of concealed weapons and explosives
represents one of the most daunting problems facing
the military and civilian law enforcement personnel.
• The exposure and identification of biological and chemical weapons is
also a major homeland security concern.
• Terahertz (THz) imaging, by virtue of its ability to penetrate materials
and its short wavelength (leading to high resolution), and THz
spectroscopy, due to its capability to recognize unique signatures of
dangerous biological and chemical agents, provide the most promising
approach to address these problems.
Homeland Security Applications
Potential Security Applications
 Detection of hidden weapons and explosives

Detecting non-metallic weapons

Postal screening of envelopes for bacteria

Chem/bio detection
Envelope
Postal screening
Explosives
Stand-off detection
Security screening wand
Terahertz Images Can Reveal Objects Concealed
Under Cloth, Paper, Tape, Even Behind Walls
Objects Concealed Under clothes
Knife Wrapped in Newspaper
See Through Prototype
System
Universal Automation Mechanism:
Developed in Matlab
Utilized29GPIB bus and parallel port protocol
Powerful Medical Imaging Capabilities of THz
Diseased
skin
Normal skin
White light image
Skin Cancer
THz image
Brain
Dental
THz device and probe (TeraView)
CONFORMAL ANTENNAS
…Fast Computations, New Materials…
• New Exotic Materials have been recently
developed.
• Stealth Technology and Many others
can benefit
E-Textiles
Courses Offered at UT
Fields
Antennas and Propagation
Microwave circuits
EMC
Electromagnetic Fields I
Electromagnetic Fields II
Phased Array Antennas I
Phased Array Antennas II
Wireless Communications
Holographic Antenna Features
• True re-configurable aperture, NOT simple
switching.
• The surface wave provides relatively low loss
RF distribution channels
• Phased array performance without phased
array feed complexity or cost
• Highly compact package
Conductive Fringe Pattern
Conductive Region (Yellow)
Non-Conductive Region (Blue)
Far-Field Pattern
Radar Scanned
Aim Point
Radar Azimuth (deg):
Radar Elevation (deg):
015
000
Description of Scenario:
• Search Along Azimuth 0-30 Deg, 0 Deg Elevation
• Array Turned ‘Off’ - Non-Conducting Surface
• Search Along Azimuth 30 Deg to 0 Deg, 5 Deg
Elevation
• Place Target Into Track, Then Lose Track
• Switch to Wide Beam to Re-Acquire Target
• Continue Target Track
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
000
000
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
005
000
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
010
000
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
015
000
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
020
000
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
025
000
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
030
000
Mode: OFF
Radar Azimuth (deg):
Radar Elevation (deg):
000
000
Mode: OFF
Radar Azimuth (deg):
Radar Elevation (deg):
000
000
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
030
005
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
025
005
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
020
005
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
015
005
Mode: Search
Radar Azimuth (deg):
Radar Elevation (deg):
010
005
Mode: Track
Radar Azimuth (deg):
Radar Elevation (deg):
012
006
Mode: Track
Radar Azimuth (deg):
Radar Elevation (deg):
016
010
Mode: Track
Radar Azimuth (deg):
Radar Elevation (deg):
020
014
Mode: Re-Acquire
Radar Azimuth (deg):
Radar Elevation (deg):
020
014
Mode: Re-Acquire
Radar Azimuth (deg):
Radar Elevation (deg):
020
018
Mode: Re-Acquire
Radar Azimuth (deg):
Radar Elevation (deg):
016
018
Mode: Re-Acquire
Radar Azimuth (deg):
Radar Elevation (deg):
016
014
Mode: Track
Radar Azimuth (deg):
Radar Elevation (deg):
018
016
Mode: Track
Radar Azimuth (deg):
Radar Elevation (deg):
021
018
Mode: Track
Radar Azimuth (deg):
Radar Elevation (deg):
024
020