A study on the broadband transitions between microstrip line and post-wall waveguide in E-band

This paper proposes design considerations for broadband input and output (I/O) transition between microstrip line (MSL) and post-wall waveguide (PWW) for E-band applications. To truly realize broadband operation, design of an anti-pad has to be taken into consideration together with the length and position of a blind-via (feeding-pin). The anti-pad is a ring-shaped space formed into the top broad wall of the waveguide at around the blind-via. We show the effect of the anti-pad on the impedance bandwidth of the I/O transition through simulation and experiment. As a result, we realized the transition with 32.4% impedance bandwidth centered at 77.5 GHz in a silica-based PWW.