Differential Cancellation Based RF Switch Enabling High Isolation and Minimal Insertion Loss in 0.0006 mm2 Area

An RF switch technique applying differential signal cancellation is presented. The proposed approach enables high isolation and extremely small size by employing cascode current steering within a differential amplifier. Unlike series RF switches, isolation is limited by device mismatch, not switch parasitic capacitance, enabling high frequency operation. Since the switch is within the already present cascode devices, there is no additional insertion loss from the switch. The switch was implemented in a 180 nm CMOS process within an amplifier as part of an on-chip receiver and achieves 36–43 dB isolation across 0.5–2 GHz, while occupying an area of only 0.0006 mm
²
.