a novel type of pattern synthesis implementation using
TRANSCRIPT
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Integrity Service Excellence
IEEE - AP-S – Vancouver 2015
A Novel Type of Pattern Synthesis
Implementation using Corrugated
Apertures
September 2016
N. Herscovici (1) and Anatoliy Borrysenko (2)
(1) Sensors Directorate
Air Force Research Laboratory
Wright-Patterson AFB OH
A&E Partnership, Inc.
Belchertown, MA
2
Outline
• Previous Work
• Motivation
• Concepts
• Challenges
• Antenna Design
• Conclusions
• Future Work
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Motivation
Antenna Pattern synthesis implementations
Amplitude and Phase Synthesis
Shaped Apertures
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Previous Work
Naftali Herscovici - The Shaped-Beam Polyrod Antenna,
IEEE Antennas and Propagation Magazine. Vol. 36, No.2. April,1994, pp.55-57.
Antenna Designer's Notebook
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Previous Work
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Elevation Patterns Azimuth Patterns
Measured Data
Naftali Herscovici - The Shaped-Beam Polyrod Antenna,
IEEE Antennas and Propagation Magazine. Vol. 36, No.2. April,1994, pp.55-57.
Antenna Designer's Notebook
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HFSS Model
The Dielectric Rod Cosecant Antenna
WR90
Elevation Radiation Patterns
Validation of the Empirical Design
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Antenna 2D Profile Definition
Major functional parts: a. feeding section
b. parallel plate waveguide section
c. launching section
d. shaped Polyrod Antenna
e. matching tip
2D Profile View
3D View
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FEM Analysis
Radiation Pattern Shapes
w/o dielectric Polyrod With dielectric Polyrod
Frequencies: 9.5 , 10.0 and 10.5 GHz
Challenges
• Beam approaches cosecant shape, but requires more systematic work to
approach the cosecant square shape.
• Sidelobes near the axis of symmetry (ϑ=0O & ϑ=180O) are too high.
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Optimization Challenges
Use Cylindrical Symmetry (BOR)
• Many design parameters
• Assess and prioritize various parameter impacts
• Implementation limitation
• Use discrete parameters for optimization
• Large Computational Volume
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Case Study – Cylindrical Short Backfire Antenna
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Case Study – Cylindrical Short Backfire Antenna
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COMOSOL BOR MODULE
Body of Revolution Method (BOR )
Transforms a 3D Problem into a 2D problem
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COMOSOL ANTENNA MODEL
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FEM,TD & BOR - COMPARISON
-25.
-20.
-15.
-10.
-5.
0.
5.
10.
-180. -150. -120. -90. -60. -30. 0. 30. 60. 90. 120. 150. 180.
Gai
n[d
B]
Angle[deg]
3D FEM,TD vs BOR - 14.4GHzFEM BOR TD
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FEM,TD & BOR - COMPARISON
-25.
-20.
-15.
-10.
-5.
0.
5.
10.
-180. -150. -120. -90. -60. -30. 0. 30. 60. 90. 120. 150. 180.
Gai
n[d
B]
Angle[deg]
3D FEM,TD vs BOR - 14.9GHzFEM BOR TD
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FEM,TD & BOR - COMPARISON
-25.
-20.
-15.
-10.
-5.
0.
5.
10.
-180. -150. -120. -90. -60. -30. 0. 30. 60. 90. 120. 150. 180.
Gai
n[d
B]
Angle[deg]
3D FEM,TD vs BOR - 15.4GHzFEM BOR TD
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FEM & BOR - COMPARISON
-25.
-20.
-15.
-10.
-5.
0.
13 14 15 16
Spar
[dB
]
Frequency [GHz]
3D FEM,TD vs BOR - Return LossFEM BOR TD
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Shaped Beam Cylindrical Array
COMSOL Optimized BOR Geometry
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Shaped Beam Cylindrical Array
Optimization Results
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Shaped Beam Cylindrical Array
Comparison between the initial geometry and the
optimized results
Shaped Beam Cylindrical Array
Improved gain and sidelobe level
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Conclusions
• Optimization the performance of shaped
beam antennas using COMSOL BOR
module was performed.
• The optimization results produced an
antenna with higher beam efficiency
(Higher Gain and lower sidelobes)
• The corrugated ridges were proved to be
an efficient tool for pattern shaping.
• The COMSOL BOR module was validated
to be an appropriate method to be used in
the optimization process.
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Future Work
• Optimize the performance of shaped beam
antennas using COMSOL BOR for Cosec2
pattern in elevation.
• Investigate possibility for broadband behavior.