ElectroScience Laboratory

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Novel UWB Dual Polarized Tapered Chamber Feed
Development Update
Kwan-ho Lee
Robert Lee, Advisor Chi-Chih Chen, Supervisor

• ElectroScience Laboratory
• Department of Electrical Engineering
• Ohio State University.

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OUTLINE

• Introduction
• Tapered Chamber Geometry
• Numerical Modeling of Tapered Chamber
• Common Tapered chamber Antenna Configurations
• Feed design and numerical result
• Prototype construction and Radiation power issue
• Cut-off frequency
• Inductive region
• Performance Improvement and result
• Measured Near field probe Result
• Discussion and future directions of tapered
  chamber and feed design

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INTRODUCTION
SBH feed antenna
Test zone
Feed section
ETS-Lindgren Wireless Test Chambers (400 MHz to
6000 MHz)
Sat Com Electronics Antenna Tapered Chamber (500
MHZ 40 GHz)

• Image source http//www.ets-lindgren.com/ and
  http//www.satcomweb.com/

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TAPERED CHMBER GEOMETRY
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MODELING OF FEED SECTION
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COMMON CONFIGURATIONS
200 MHz
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FEED ANTENNA DESIGN
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FEED ANTENNA DESIGN (cont.)
From the FDTD, we can obtain
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INNER FIELD DISTRIBUTIONS 1.
F 200 MHz
F 3000 MHz
Co-Polarization field magnitude (Ex)
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INNER FIELD DISTRIBUTIONS 2.
F 200 MHz
F 3000 MHz
Co-Polarization field phase (Ex)
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INNER FIELD DISTRIBUTIONS 3.
F 200 MHz
F 3000 MHz
Co-Polarization field magnitude (Ex)
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INNER FIELD DISTRIBUTIONS 3.
F 200 MHz
F 3000 MHz
Co-Polarization field phase (Ex)
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PROTOTYPE CONSTRUCTION
Need Improvement
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RADIATED POWER ISSUE
absorber removed completely
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IMBEDED QUAD-RIDGED LAUNCHER FOR CONICAL FEED
SECTION
Proposed Antenna
Slant absorber cut


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IMBEDED QUAD-RIDGED LAUNCHER FOR CONICAL FEED
SECTION - RESULT
Improvement
Introduce throat region
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INNER FIELD DISTRIBUTIONS 1.
F 200 MHz
F 3000 MHz
Co-Polarization field magnitude (Ex)
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INNER FIELD DISTRIBUTIONS 2.
F 200 MHz
F 3000 MHz
Co-Polarization field phase (Ex)
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INNER FIELD DISTRIBUTIONS 3.
F 200 MHz
F 3000 MHz
Co-Polarization field magnitude (Ex)
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INNER FIELD DISTRIBUTIONS 3.
F 200 MHz
F 3000 MHz
Co-Polarization field phase (Ex)
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PROTOTYPE IMPROVED DESIGN
Prototype antenna installed inside the feed
section and close view at feeding point

• Near field probing by facing inside the anechoic
  chamber.
• Used near field probe is 1.5 inch monopole.

Vertical scan scheme
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MEASURED PHASE DISTRIBUTIONS
2500 MHz
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DISCUSSION
PROTOTYPE IMPROVED DESIGN
Antenna ringing
Inductive region 1
x
Phase center movement
z
1 L. Du, Wave propagation in conical
waveguide, Antennas and Propagation Society
International Symposium, Volume 12 , pp. 89-91,
Jun 1974.
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NEXT GENERATION TAPERED CHAMBER FEED CONFIGURATION

• Cylinder Feed section configuration

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NEXT GENERATION TAPERED CHAMBER FEED CONFIGURATION
3 dB

• Absorber -gt

Interactions

• Launcher -gt