29-/35 GHz Dual-band high-gain phase shifter with hybrid π-networks

This Letter presents a 29-/35 GHz dual-band high-gain hybrid π-network-based phase shifter. The hybrid π-network realised by combining electrical tuning through capacitors and magnetic tuning through transformers extends the phase shift range. Furthermore, the phase shift modules are inserted between the vertically stacking transistors to realise the embedded phase shifting with the minimum loss. The Gm-stages offer the additional signal gain to offset attenuation from the passive phase shifter. This prototype, fabricated in a 28 nm CMOS process, demonstrates a 360° continuous phase shift range with a maximum gain of 22 dB at 35 GHz, and 240° continuous phase shift range with a maximum gain of 20 dB at 29 GHz. It consumes 26 mW power and 1.25 mm × 0.75 mm chip area.