Investigation of the de-embedding issue of CPWs on silicon substrates at high frequency

In this paper, coplanar waveguide (CPW) transmission lines that require pads and transitions are fabricated on 8000 Ω-cm and 15 Ω-cm silicon substrates and measured up to 220 GHz using 50 μm pitch probes. Several deembedding methods are applied to the raw measured data, and then compared with the simulated lines without the pads and transitions. The open-short de-embedding method loses its accuracy when the frequency is greater than 60GHz. The twoline, thru-line and EM-simulated pad de-embedding methods lose precision in the 140-220GHz range. The TRL calibration is the most accurate method compared to others up to 220GHz.