A 35 GHz Hybrid π-Network High-Gain Phase Shifter with 360° Continuous Phase Shift Range

This paper presents a 35 GHz high-gain phase shifter with 360 continuous phase shift range. To enhance the phase shift range, a hybrid pi-network by combining both electrical tuning through capacitors and magnetic tuning through transformers is developed. The phase shift modules are inserted between vertically stacking transistors to realize the embedded phase shifting with the minimum loss. Furthermore, the Gm-stages offer the additional signal gain to suppress attenuation in the phase shifter. The cap-neutralization technology is utilized to further increase the gain and stability. This prototype, fabricated in a 28 nm CMOS process, demonstrates a 360 degrees continuous phase shift and maximum gain of 25.6 dB. It consumes 26 mW power and 1.25 mm x 0.75 mm chip area.