Waveguide to microstrip probe transition for Ka-band transceiver applications

In this paper, we designed and fabricated the Ka-band waveguide to microstrip transition using probe. The transition is consisted of probe, inductive line, λ/4 impedance transformer, and 50 Ω microstrip line. We inspected and optimized the characteristic impedances and the lengths of each component by using HFSS simulator. The performance of the fabricated transition exhibits an average insertion loss of 0.6 dB in a frequency range of 31 ∼ 40 GHz. The return loss is better than 10 dB between 31 GHz to 40 GHz. Especially, at the center frequency (35 GHz), the insertion loss is about 0.3 dB and the return loss is below −29 dB. The measured results well agree with the simulated results. The designed and fabricated waveguide to microstrip transition shows a simple structure, a low insertion loss, and the broadband characteristics. Also, it is very useful for the application in Ka-band transceiver.