60-GHz 5-bit Phase Shifter With Integrated VGA Phase-Error Compensation.

A 57–64-GHz low phase-error 5-bit switch-type phase shifter integrated with a low phase-variation variable gain amplifier (VGA) is implemented through TSMC 90-nm CMOS low-power technology. Using the phase compensation technique, the proposed VGA can provide appropriate gain tuning with almost constant phase characteristics, thus greatly reducing the phase-tuning complexity in a phased-array system. The measured root mean square (rms) phase error of the 5-bit phase shifter is 2^\circ at 62 GHz. The phase shifter has a low group-delay deviation (phase distortion) of +/-8.5 ps and an excellent insertion loss flatness of \pm0.8 dB for a specific phase-shifting state, across 57–64 GHz. For all 32 states, the insertion loss is 14.6 \pm 3 dB, including pad loss at 60 GHz. For the integrated phase shifter and VGA, the VGA can provide 6.2-dB gain tuning range, which is wide enough to cover the loss variation of the phase shifter, with only 1.86^\circ phase variation. The measured rms phase error of the 5-bit phase shifter and VGA is 3.8^\circ at 63 GHz. The insertion loss of all 32 states is 5.4 dB, including pad loss at 60 GHz, and the loss flatness is \pm0.8 dB over 57–64 GHz. To the best of our knowledge, the 5-bit phase shifter presents the best rms phase error at center frequency among the V-band switch-type phase shifter. [ABSTRACT FROM AUTHOR]