A 28 GHz Digital-Controlled 4-bit Vector Modulator Based Phase Shifter Design

This paper presents a 4-bit digital-controlled active phase shifter implemented in a 0.25µm SiGe:C BiCMOS process for the fifth-generation (5G) communication. It is designed to cover 27.5 GHz to 28.35 GHz spectrum and to achieve balance among power gain, phase accuracy, power consumption and size. The input signal is first divided into two paths by a transformer-based quadrature generator and then weighted summed by a Gilbert typed variable gain amplifier (VGA). Based on the simulation, the proposed phase shifter achieves average 5.4 dB power gain with 17.5mW power consumption, while obtaining less than 1.5 dB rms gain error from 27 to 28.5 GHz. Both input and output reflection coefficients are lower than -10 dB in the whole designed frequency range.