A highly linear bidirectional phase shifter based on vector modulator for 60GHz applications

This paper presents a phase shifter for beam steered systems at mmW frequencies. It is based on an I/Q hybrid transformer feeding a vector modulator that weights the amplitude of quadrature differential signals. A specific passive attenuator has been designed to improve the attenuation depth, the phase accuracy and the impedance matching. A CMOS 55nm circuit was measured, that covers the 360° phase shift with less than 1 dB gain and 5° phase imbalance. It covers the frequency band from 55 to 67 GHz and paves the way towards mobile millimeter-wave high data rate telecommunication systems.