Performance Improvements of Reverse-Saturated SiGe HBT Millimeter-Wave Switches with Floating Emitter Configuration

This work demonstrates the advantages of using reverse-saturated SiGe HBTs in a floating-emitter (FE) configuration compared to the standard grounded-emitter (GE) configuration, for improved millimeter-wave (mm-wave) switch design. A W-band quarter-wave shunt, single-pole double-throw (SPDT) switch test structure was designed in a 130-nm SiGe BiCMOS technology to prove the efficacy of this assertion. The minimum insertion loss of the switch is 2.3 dB in both the FE and GE configurations. However, the switch shows 17.5 dBm input-referred 1-dB compression (IP
1dB
) in the GE configuration, and 19.7 dBm IP
1dB
in the FE configuration. Moreover, the switch consumes 6.9 mW DC power in GE configuration with 1.0 V bias but only 5.5 mW in FE configuration. Although in the FE configuration, the SiGe HBT experiences a substantially higher level of 1-V damage under high-power RF stress, the damage is shown not to degrade the RF performance of the switch.