A 94-GHz Absorptive SP4T Switch with Pad Parasitic Cancellation

An absorptive single-pole four-throw switch network is designed at 94 GHz by using the
$\lambda / 4$
transmission-line approach in 90 nm CMOS technology for the application of Butler matrix beamforming control. Over the frequency range from 85 GHz to 102 GHz, the return loss of the network is better than 10 dB, and the isolation better than 27 dB. The insertion loss of signal transmission achieves 4.4 dB at 94 GHz.