A hybrid pi/t bit passive topology is presented to enable a significant reduction in the die area for a high-pass/low-pass phase shifter is presented. A hybrid-topology 5 bit digital X-band phase shifter was designed, fabricated and tested using a 200 GHz, 0.13 µm SiGe bipolar complementary metal oxide semiconductor (BiCMOS) technology. Size and performance characteristics are presented as a contrast to an all-pi phase shifter recently presented by Comeau et al. using the same SiGe BiCMOS technology and design goals. With similar bit passive performance to the all-pi design, the hybrid shifter allows for a total shifter die-area reduction of 50.5%. The absolute phase error of the shifter was less than ±13 from 8 to 12 GHz, with an average insertion loss of −20 dB.

5 bit, silicon-based, X-band phase shifter using a hybrid pi/t high-pass/low-pass topology