Micromachined Ridge Gap Waveguide Transmission Line and Transition at 220-310 GHz

Paper in proceeding, 2021

This paper presents a vertical wideband transition between a standard WR-3.4 rectangular waveguide (RW) and ridge gap waveguide (RGW) operating at 220-310 GHz. To achieve a wideband impedance matching a capacitive stub is used instead of multiple steps in the ridge section to reduce the manufacturing complexity. The designed back-to-back transition is fabricated with SUEX dry film photoresist. The attractive features of the designed transition are simplicity and high tolerances to manufacturing errors, without compromising the wideband performance. The measurement results of the fabricated prototype show good agreement with simulations over the frequency band of interest and the measured average insertion loss is 0.075 dB/mm and the measured input reflection coefficient is below -12 dB for the back-to-back structure. Measurement results indicate that SUEX dry film photoresist is a suitable material to fabricate waveguide components operating at and above the millimeter-wave range.