Waveguide to microstrip probe transition for millimetre wave applications using LTCC technology

An improved waveguide to microstrip probe transition based on LTCC (Low Temperature Co-fired Ceramic) technology is proposed at Ka-band. To widen the bandwidth of the transition, a matching structure beneath the probe is buried, which is formed by installing conducting ground stripes on different substrate layers connected by the staggered via side walls. The improved transition achieves over the specified 30 GHz~35.2 GHz wideband range, while its return loss is better than 20 dB and its minimum insertion loss is 0.3 dB, according to the simulated results of HFSS, and the implemented module is compact in size (11 × 9 × 1.026 mm³).