Millimeter-Wave Microstrip Line to Waveguide Transition Fabricated on a Single Layer Dielectric Substrate

Hideo IIZUKA  Toshiaki WATANABE  Kazuo SATO  Kunitoshi NISHIKAWA  

IEICE TRANSACTIONS on Communications   Vol.E85-B    No.6    pp.1169-1177
Publication Date: 2002/06/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Antenna and Propagation
millimeter wave,  transition,  microstrip line,  waveguide,  finite element method,  

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We propose a new type of microstrip line to waveguide transition fabricated on a single layer dielectric substrate. Impedance matching of the transition is achieved by controlling the size of a matching element and the length of an inserted microstrip line across a waveguide. As a result of experiments, low transmission loss of 0.4 dB is realized at the design frequency of 76.5 GHz. Bandwidth of the transition is numerically investigated by the finite element method. It is clarified that the bandwidth of the transition becomes wider as the cross section of the waveguide becomes smaller and twice as wide as that of a conventional microstrip patch antenna element fabricated on a dielectric substrate with the same parameters. In addition, the effect of errors in relative position between the dielectric substrate and the waveguide is also investigated. It becomes clear that degradation of transmission characteristics is caused by the shift of resonant frequency and keeps less than 0.1 dB for a manufacturing accuracy within 0.1 mm.