A high power handling capability CMOS T/R switch for X-band phased array antenna systems

This paper presents a single-pole double-throw (SPDT) transmit/receive (T/R) switch fabricated in 0.25-μm SiGe BiCMOS process for X-Band (8-12 GHz) phased array radar applications. The switch is based on series-shunt topology with combination of techniques to improve insertion loss (IL), isolation and power handling capability (P_1dB). These techniques include optimization of transistor widths for lower insertion loss and parallel resonance technique to improve isolation. In addition, DC biasing of input and output ports, on-chip impedance transformation networks (ITN) and resistive body-floating are used to improve P_1dB of the switch. All these design techniques resulted in a measured IL of 3.6 dB, isolation of 30.8 dB and P_1dB of 28.2 dBm at 10 GHz. The return losses at both input and output ports are better than 16 dB from 8 to 12 GHz. To our knowledge, this work presents the highest P_1dB at X-Band compared to other reported single-ended CMOS T/R switches in the literature.