Low-loss Coplanar Waveguide to WR-5 Waveguide E-plane Transition with Bias-Tee.

We present a grounded co-planar to WR-5 waveguide transition with a bias-tee designed for integration of photodiodes and similar biased devices. The planar waveguide circuit is based on a $75 \mu \mathrm{m}$ thick quartz substrate and allows the packaging of the device in a metallic split-block configuration. The transition operates over the band from 140 to 170 GHz with a return loss of less than -0.3 dB.