Ultra-Compact High-Linearity High-Power Fully Integrated DC–20-GHz 0.18-μm CMOS T/R Switch

A fully integrated ultra-broadband transmit/receive (T/R) switch has been developed using nMOS transistors with a deep n-well in a standard 0.18-mum CMOS process, and demonstrates unprecedented insertion loss, isolation, power handling, and linearity. The new CMOS T/R switch exploits patterned-ground-shield on-chip inductors together with MOSFET's parasitic capacitances to synthesize artificial transmission lines, which result in low insertion loss over an extremely wide bandwidth. Negative bias to the bulk or positive bias to the drain of the MOSFET devices with floating bulk is used to reduce effects of the parasitic diodes, leading to enhanced linearity and power handling for the switch. Within dc-10, 10-18, and 18-20 GHz, the developed CMOS T/R switch exhibits insertion loss of less than 0.7, 1.0, and 2.5 dB and isolation between 32-60, 25-32, and 25-27 dB, respectively. The measured 1-dB power compression point and input third-order intercept point reach as high as 26.2 and 41 dBm, respectively. The new CMOS T/R switch has a die area of only 230 mumtimes250 mum. The achieved ultra-broadband performance and high power-handling capability, approaching those achieved in GaAs-based T/R switches, along with the full-integration ability confirm the usefulness of switches in CMOS technology, and demonstrate their great potential for many broadband CMOS radar and communication applications