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-mu m 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 P1dB of the switch. All these design techniques resulted in a measured IL of 3.6 dB, isolation of 30.8 dB and P1dB 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 P1dB at X-Band compared to other reported single-ended CMOS T/R switches in the literature.