A 30-88 GHz Phase Shifter with Broadband 90° Hybrid- Marchand Balun Network and Common-base Buffer Achieving 1.34-3.1° RMS Phase Error in 90 nm SiGe

To enable a software-defined spectrally agile phased array operation across multiple bands from 30-100 GHz, we present a 30-88 GHz broadband IQ vector modulator phase shifter in 90 nm SiGe. This was enabled by 1) A single-end to differential quadrature phase generator consisting of a compact Marchand balun and 90°hybrid-based bandwidth extension network; 2) A common-base (CB) stage as the input buffer of the IQ VGA. Across the 58 GHz bandwidth, the maximum phase error of the 5-bit phase shifter is below half LSB resolution while achieving rms phase error of 1.34-3.1° and rms gain error of 0.19-0.48 dB. To the best of the authors' knowledge, this is the first phase shifter that covers from 5G FR2 to W band with a fractional bandwidth of 98.3% and demonstrates the best amplitude/phase error over one of the widest bandwidths.