A Dual-Band Vector-Sum Phase Shifter for 28-GHz and 60-GHz Phased Arrays in 65-nm CMOS

This paper presents a 5-bit dual-band active phase shifter for both 28-GHz and 60-GHz phased array applications. With the inclusion of a dual-band hybrid transformer-based quadrature generator and a wide-band vector modulator, this phase shifter achieves 3-dB gain bandwidth of 27-34 GHz and 55-63 GHz. The vector modulator is composed of a balun-loaded buffer and a Gilbert cell-based variable gain amplifier (VGA). Further, a digital-to-analog convertor (DAC) controls the gain of vector modulator to achieve 5-bit phase resolution. The circuit is designed in a 65-nm CMOS technology. Post layout simulation results show that the RMS phase error is 2.27° ~ 2.94° and 1.96° ~ 3.07° and the RMS gain error is 1.17 ~ 1.53dB and 1.26 ~ 1.91dB in the 3-dB bandwidths of 27-34 GHz and 55-63 GHz, respectively. The post-layout simulated input-referred 1-dB compression point (IP
1dB
) is larger than −8.7dBm, while the peak gain is −0.17dB at 29 GHz with an average power consumption of all phase states of 32.4 mW. The core area of the phase shifter is 560 $\mu m\times 560 \mu$m.