A Single-Layer Hollow-Waveguide 8-Way Butler Matrix

Shin-ichi YAMAMOTO  Jiro HIROKAWA  Makoto ANDO  

IEICE TRANSACTIONS on Electronics   Vol.E89-C    No.7    pp.1080-1088
Publication Date: 2006/07/01
Online ISSN: 1745-1353
DOI: 10.1093/ietele/e89-c.7.1080
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Microwaves, Millimeter-Waves
short-slot coupler,  length reduction,  Butler matrix,  waveguide structure,  single-layer,  low loss,  

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The authors propose a single-layer hollow-waveguide 8-way Butler matrix. All components of the Butler matrix are in a single layer which contributes to low-cost fabrication. To reduce the length of the couplers, a step structure is installed in the coupled region. 50% length reduction is obtained in comparison with the conventional design using reflection-suppressing posts in the coupled region. The total size of the matrix is 17.1λg6.0λg. The full structure of the matrix is fabricated by hollow waveguides at 22 GHz band and the total measured loss is only 0.25 dB.