Low-loss and Small-size 28 GHz CMOS SPDT Switches using Switched Inductor

Abstract

In this paper, low-loss and small-size single-pole double-throw (SPDT) switches using a switched inductor are presented. The switched inductor is composed of a single inductor and two inductor switches which reconfigure the inductor between two output ports. It is designed to be connected to a turned-off series FET switch to resonate out the off-capacitance. All ports are matched to 50 Ohm by using the single inductor, which allows it to have low insertion loss (IL) and small size. Two types of SPDT switches which have the switched inductor are implemented in 65 nm CMOS process, one is a series type switch and the other is series-shunt type one. The series type one shows 0.89 dB IL, 18.2 dB isolation and the input P1dB of 12.55 dBm at 28 GHz, whereas the series-shunt type one shows 1.06 dB IL, 39 dB isolation and the input P1dB of 7.25 dBm. Both SPDT switches are operated in 25–39.5 GHz maintaining return loss less than −20 dB. Size of series and series-shunt type of the SPDT switches are 0.009 mm2 and 0.01 mm2, respectively.