Submillimeter-Wave Waveguide-to-Microstrip Transitions for Wide Circuits/Wafers

초록

Microstrip transitions for wide circuits/wafers are proposed using stub arrays (SAs) and indented waveguides (IWs). Full-wave analysis is performed to show that the proposed techniques can effectively suppress the resonances excited in the slit region which is needed to accommodate wide substrates. H-band waveguide-to-microstrip transitions consisting of two directors, dipole antenna, and balun were fabricated including the proposed techniques, accommodating a 1220-mu m-wide substrate which is about three times the width of WR-03 standard waveguide (430 mu m). The slit region is 1300 mu m wide and 90 mu m high. The comparison of measurement results between four transitions proves that the proposed SAs and IWs can successfully eliminate in-band resonances and greatly enhance the bandwidth of the transitions. The transition with both SAs and IW exhibits the best performance, a back-to-back loss of 2.3 dB across 234-314 GHz, where the variation in the insertion losswas less than +/- 0.5 dB. This insertion loss includes the losses in the microstrip line and 3-cm-longwaveguide section. The return loss is better than 13.7 dB in this frequency range. Bandwidth for 10-dB return loss is as large as 97 GHz from 227 to 324 GHz.

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