A 4.5–18-GHz CMOS Vector-Modulated Phase Shifter With Single-Stage Tunable Polyphase Filter and Built-In Automatic IQ-Vector Calibration Loop

This article presents a frequency-tunable CMOS vector-modulated phase shifter (VMPS) from 4.5 to 18 GHz. The design uses a single-stage tunable polyphase filter (PPF) with a built-in automatic calibration loop (BIACL), which adjusts the PPF resistance based on the detected amplitudes of the in-phase and quadrature (IQ) vectors to achieve center frequency calibration. The structurally optimized BIACL consists of amplitude detectors, a comparator, autocontrol logic, and a resistance digital-to-analog converter (RDAC). The amplitude detector, based on a Gilbert cell, achieves a 23-dB detection range with wide bandwidth and high sensitivity, offering enhanced performance in amplitude detection. For phase control, two independent cascode variable-gain amplifiers (VGAs) with tail-current switches are used for vector modulation. The VMPS is implemented in 65-nm CMOS technology, occupying a core chip area of 1.08 mm². It demonstrates a wideband 6-bit 360° phase-shifting capability across 4.5–18 GHz with a calibration range from −14 to 2 dBm and achieves <2.3° rms phase error and <1.3-dB maximum gain error.