A Wideband Contactless CPW to $W$ -Band Waveguide Transition

A wideband, contactless, coplanar waveguide (CPW) to rectangular waveguide transition integrated with an $E$ -plane bend at a ${W}$ -band is proposed. The transition utilizes a four-step Chebyshev ridge waveguide impedance transformer and a $\lambda _{g}$ /4 matching stub over the quartz CPW to ensure the wider impedance matching and to maintain a good electrical contact, without any soldering or gluing. The novel transition has a simple structure and a low insertion loss. The back-to-back prototype is fabricated and measured, and the measured reflection coefficient remains better than −10-dB over the entire ${W}$ -band, while the insertion loss is on average 1.2 dB in the range of 80–109 GHz (31.5% bandwidth). Also, the design is fully scalable to any other frequency band of interest.