Broadband Partially Covered Microstrip-to-Waveguide Transition With Enhanced Radiation Suppression for Millimeter-Wave Transmission

A broadband microstrip-to-waveguide transition (MWT) structure is reported for efficient millimeter-wave (mm-wave) signal delivery. The transition design, incorporating a printed circuit board (PCB) with three copper layers and two dielectric layers to realize a partially covered microstrip line (MSL) and a via fence, achieves low loss and broadband signal delivery by suppressing radiation leakage and by using multiple resonances, respectively. A back-to-back (B2B) measurement was performed to validate the MWT design. It exhibited a return loss (RL) greater than 10 dB in the frequency range of 41–63 GHz, with an operating bandwidth of 42%. The proposed MWT exhibits good RL, low radiation loss, and broadband performances at mm-wave frequencies.