A 4-Bit Passive Phase Shifter for Automotive Radar Applications in 0.13 μm CMOS

This paper presents a 67-78 GHz 4-bit passive phase shifter using CMOS switches available in the 0.12 mum SiGe BiCMOS process (IBM 8HP). The phase shifter is based on a low-pass pi-network and CMOS passive transistors. The phase shifter achieves -19.2+/-3.7 dB of gain including pad loss at 77 GHz. The RMS phase error is less than 11.25deg and the RMS gain error is less than 2.5 dB over the 67 78 GHz range. The total chip size is 450 times 300 mum² (0.135 mm²), excluding pads, and the chip consumes virtually no power. The measured P_1dB is > +8 dBm at 77 GHz and the simulated IIP3 is > 22 dBm, making it possible to precede this design with a high gain LNA without loss of system linearity or input power handling.