A differential sub-nanosecond high-isolation absorptive active SiGe 24 GHz switch for UWB applications

This paper presents the design and measurement of a SiGe sub-nanosecond, high isolation, single-pole double-throw (SPDT) and single-pole single-throw (SPST) differential absorptive active switch at 24 GHz for ultrawideband (UWB) applications. The switch and digital driver consume 24 mA from a 5 V supply. The active area of the SPDT and SPST is 1000 μm × 550 μm and 670 μm × 340 μm respectively. The novel circuit topology implements a SPDT that inherently maintains the port impedances regardless of the state of the switch. The insertion loss is less than 3 dB over the 20-26 GHz range and the isolation is >42 dB at 10-30 GHz with a switching time of 100 ps.