A 0.0325-mm ^2 114-to-147-GHz 6-Bit Passive Vector-Modulated Phase Shifter With MN-Embedded Isolated Power Combiner Achieving 3.7 ^$ RMS Phase Error in 65-nm CMOS

This paper presents an ultra-compact 114-to-147-GHz 6-bit passive vector-modulated phase shifter (P-VMPS) with a compact matching network (MN) embedded isolated power combiner. The proposed power combiner consists of two coupled-line-based distributed-baluns connected in parallel to achieve impedance matching, power combining and balanced-to-unbalanced transformation. Extra coupled-lines and RC networks are added between the two differential ports for impedance matching and isolation performance enhancement. By absorbing the impedance matching and balanced-to-unbalanced transformation functions into the power combiner itself, the area of the entire phase shifter is significantly reduced. Folded quadrature hybrid coupler (QHC) and analog-controlled X-type attenuator (X-ATT) are utilized for I/Q signal generation and phase-invertible gain tuning. A proof-of-concept P-VMPS is implemented in 65-nm CMOS technology with a core area of only 0.0325 mm ^2 . Measurement results show that the proposed VMPS can provide full 360 ^{\circ} phase-shifting range with 5.625 ^{\circ} phase step. The measured RMS phase/gain error is from 1.1 to 3.7 ^{\circ} /0.6 to 1.5 dB within 114-to-147 GHz. This P-VMPS achieves superior performance in terms of phase resolution, RMS phase error and area compared with the state-of-the-art D-band phase shifters.