Small-Size Low-Loss 28-GHz Body-Floated CMOS DPDT Switch Using Shared Matching Network

A small-size low-loss double-pole double-throw switch using a shared matching network (SMN) for two I/O ports is presented in which redundant matching networks of I/O ports are combined into the simple SMN. This simplification allows it to have small-size and low-loss characteristics. The SMN is connected between the two inputs of the switch to resonate with the OFF-capacitances of the switch FETs, which is implemented with an inductor. Body-floated switch FETs are adopted for the switch, of which improvements are analyzed. The proposed switch is implemented in a 65-nm CMOS process with a series type. It operates in the range of 22-40 GHz, maintaining the return loss below -15 dB. It shows 1.3-dB insertion loss, 20-dB isolation, and IP1 dB of 6.2 dBm at 28 GHz. The insertion loss difference is measured to be less than 0.1 dB in the operating frequency. It occupies a core size of 0.022 mm
²
.