A Post-Wall Center-Feed Waveguide Circuit Consisting of T-Junctions for Reducing the Slot-Free Area in a Parallel Plate Slot Array Antenna

Koh HASHIMOTO
Jiro HIROKAWA
Makoto ANDO

Publication
IEICE TRANSACTIONS on Electronics   Vol.E93-C    No.7    pp.1047-1054
Publication Date: 2010/07/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E93.C.1047
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Progress in Microwave and Millimeter-Wave Technologies)
Category: 
Keyword: 
millimeter-wave antennas,  post-wall waveguides,  parallel plate waveguides,  slot array antennas,  center-feed antennas,  

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Summary: 
A post-wall center-feed waveguide consisting of T-junctions is proposed for reducing the slot-free area of a parallel plate slot array antenna. The width of the slot-free area is reduced from 2.6 λ0 to 2.1 λ0. A sidelobe level in the E-plane is expected to be suppressed lower than that of the conventional center-feed antenna using cross-junctions. The method of moments with solid-wall replacement designs initially the T-junctions and HFSS including the post surfaces modifies only the reflection cancelling post. We have designed and fabricated a 61.25 GHz model antenna with uniform aperture illumination. The sidelobe level in the E-plane is suppressed to -9.5 dB while that of a conventional cross-junction type is -7.8 dB. Also, we suppress it to -13.8 dB by introducing a -8.3 dB amplitude tapered distribution in the array of the radiation slot pairs.