Design of Ku-Band Bi-Directional Active Phase Shifter Enabling a Low RMS Error Utilizing Switch-Less Staggered Core with the Identical In-Out Matching

In this paper, a vector-sum active bi-directional phase shifter (VABPS) is proposed that operates in the Ku-band and has low RMS gain and phase error with low power consumption. The 3-stack switch-less staggered structure is unveiled, facilitating identical input and output (IO) matching. This feature significantly enhances the reliability of bi-directional phase-shift operations by mitigating both gain and phase errors. A transformer based hybrid coupler is adopted for generating accurate I and Q signals, followed by a bi-phase modulator that is utilized to create 180° phase inversion of I and Q signals. The proposed VABPS supports a 6-bit resolution with a phase shift range of 360°, and has an RMS phase error of less than 2° and a gain error of less than 0.6 dB. It consumes about 15.8 mW and has a chip size of 1.25 × 1.08 mm².