ABSTRACT This letter presents a millimetre‐wave continuously tunable reflection‐type phase shifter (RTPS) using a 0.25 µm GaAs process targeting the n258 band of 5G communication. A wider than 180° phase shift range is provided, while superior in‐band phase flatness with low‐loss performance is achieved. The circuit consists of a 90° Lange coupler and a pair of reflective loads where a multi‐resonance structure and schottky diode varactors are employed. Compared to conventional switch‐type phase shifters using the GaAs process, the RTPS proposed only requires one bias voltage adjustment to achieve wide‐range continuous phase shifting without DC power consumption. The proposed has a 187° phase shift range and 6.6 dB average insertion loss over the 24‐28 GHz. A machine‐learning‐based calibration model is further introduced to learn the phase–voltage mapping from simulated/measurement data, enabling fast digital phase predistortion and reducing calibration effort in phased‐array control.
Wang et al. (Thu,) studied this question.