An X-Band 5-Bit Active Phase Shifter Based on a Novel Vector-Sum Technique in 0.18μm SiGe BiCMOS

A 5-bit 360° active phase shifter of digital control with a novel two-step vector-sum technique in 0.18\mu \text{m} SiGe process is presented in this brief for X-band phased arrays. The two-step vector-sum technique is based on a sub-phase shifter array controlled by high quality logic circuit to avoid the issue of control circuit with low accuracy in the conventional scheme. The implemented phase shifter features good performance of 11.25° phase resolution and full 360° phase synthesizing between 8-12 GHz. Measurements display that the RMS gain error is below 0.6 dB while the RMS phase error is lower than 4.6°. The measured insertion loss is less than - 11.9 dB at 12 GHz while the return loss is better than - 13 dB over 8 to 12 GHz. With a 3.3V voltage supply, the DC power consumption is 73.92 mW. The designed phase shifter has a compact size of 0.6 mm^{2} .