A 5.4 mW G-Band Phase Shifter in 90-nm SiGe HBT With One-Hot Encoding

We present a compact, low-power G-band phase shifter for beamforming and/or MIMO arrays with large numbers of elements. The active phase shifter is based on a one-hot selection where the state of the phase shifter is selected from four phases. The low resolution (2-bit) per element minimizes per channel complexity and power consumption as well as supporting high switching bandwidth. A subquarter wavelength balun and broadside coupler allow compact implementation covering most of G-band. The phase shifter is implemented in a 90-nm SiGe HBT process
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375 GHz) and measured from 150 to 220 GHz with −8.7 dB average gain and a −5.7 dBm input 1-dB gain compression at 180 GHz. It consumes 5.4 mW DC power and occupies only 0.02 mm2 core area. The root-mean-square error of gain and phase were, respectively, 0.68–1.48 dB and 12–16.7° across the range.