Optimization of Coplanar Waveguide Integrated PCM Switches

This paper presents the optimization of coplanar waveguide integrated PCM switches. PCM switches isolation efficiency is directly affected by distance between ground planes above and below the transmission line. Reducing this distance from 160 µm to 26 µm, while keeping exactly the same PCM switch core, dramatically improves measured isolation from -22.2 dB to -31.1 dB at 40 GHz. Without changing the switch geometry, its figure of merit is enhanced from 18 fsec to 5.9 fsec. The design technique from this paper can be re-used for designing CMOS integrated PCM switches.