A Compact D-Band Phase Shifter with 0.1-degree Phase Resolution and 0.8-degree RMS Phase Error in 65 nm CMOS

Sub-THz phased-array transceivers play an important role in future 6th-generation mobile communication systems (6G). In particular, the phase shifter is an essential circuit for phased-array transceivers. The phase shifter must have high-resolution phase steps and low phase error to achieve high-precision beam steering and calibration [1]. This work presents a high-precision D-band cascaded phase shifter for 6 G wireless communications. The active fine-tuning phase shifter with feedback technology realizes high-resolution phase shifting. This technology achieves over three times the fine phase shift of conventional works with lower power consumption. In addition, a compact propagation delay phase shifter using a non-uniform architecture is proposed. Thanks to this technique, a 360-degree phase shift with low phase error and reduced insertion loss is realized. The proposed phase shifter achieves a phase step of 0.1° and RMS phase error of 0.8° within the frequency range of 150-160 GHz. The power consumption is 5 mW, and the IC core area is $0.099 \mathrm{~mm}^{2}$, fabricated in a 65 nm CMOS process.