X-Band 6-Bit Phase Shifter with Low RMS Phase and Amplitude Errors in 0.13-㎛ CMOS Technology

Abstract

This paper proposes a CMOS 6-bit phase shifter with low RMS phase and amplitude errors for an X-band phased array antenna. The phase shifter combines a switched-path topology for coarse phase states and a switch-filter topology for fine phase states. The coarse phase shifter is composed of phase shifting elements, single-pole double-throw (SPDT), and double-pole double-throw (DPDT) switches. The fine phase shifter uses a switched LC filter. The phase coverage is 354.35° with an LSB of 5.625°. The RMS phase error is ＜ 6° and the RMS amplitude error is ＜ 0.45 ㏈ at 8–12 GHz. The measured insertion loss is ＜ 15 ㏈, and the return losses for input and output are ＞ 13 ㏈ at 8–12 ㎓. The input P1dB of the phase shifter achieves > 11 ㏈m at 8–12 ㎓. The current consumption is zero with a 1.2-V supply voltage. The chip size is 1.46´0.83 ㎟, including pads.