A 25–30-GHz RMS Error-Minimized 360° Continuous Analog Phase Shifter Using Closed-Loop Self-Tuning I/Q Generator

A novel wideband analog phase shifter employing a self-tuning
$I/Q$
generator is proposed in this article. It can provide 360° continuous phase shift with very low rms gain and phase error while consuming 22.8 mW from a 1-V supply with the phase shifter core dissipating only 11.2 mW. Cartesian-combining method has been employed to provide better control over sidelobes in a phased array network application. The phase shifter is fabricated in 65-nm CMOS and occupies a core area of only 0.12 mm
²
. Employing the self-tuning
$I/Q$
generator in an error feedback control loop, a single-stage poly-phase-filter (
RC
-PPF) is tuned by changing the gate voltage of triode-regime nMOS resistors. This self-tuning-loop provides
$I/Q$
amplitude imbalance and phase error under 0.3 dB and 1.1°, respectively. This reduces the rms gain error and phase error of the phase shifter below 0.4 dB and 1.6° respectively for a 5-GHz bandwidth (25–30 GHz). The
I/Q
generator circuit consumes a dc-bias current of only 2 mA. The tunable insertionloss varies by around 7 dB and the 1-dB compression point IP1dB is in the range
$-7.5\,\,\pm \,\,2.6$
dBm near the center frequency. The proposed phase shifter can be a good fit for radio detection and ranging (RADAR) within the
$K$
- and
Ka
-bands, as well as, for future 5G application in the 26.5–29.5 GHz range.