Low-Voltage CMOS Quadrature Phase Shifter

Quadrature phase shifter (QPS) plays a crucial role in modern communication systems, offering a generation of orthogonal signals for various applications such as radar, wireless communication, and image rejection. This research focuses on the implementation of a compact CMOS-130 nm design of a low-voltage and low-power QPS. Existing QPS designs suffer from some limitations in phase/amplitude accuracy, power consumption, and circuitry complexity. The objective of this research is to enhance the performance of QPS while maintaining the simplicity of the design. The proposed low-voltage CMOS QPS is integrated with a calibration system to tune the pole frequency of the output signal and maintain an accurate quadrature phase. The proposed design is based on high-pass and low-pass filters, rectifier, and comparator functions. The QPS is designed to operate at low frequencies up to 850 MHz with a ± 0.5 V power supply and a power consumption of 0.38 mW. It exhibits a phase error of ± 0.8° and 0.25 dB magnitude discrepancies between the output signal and its quadrature phase version. The circuit designs for 130-nm CMOS technology, based on the BSIM4 model, are included with simulated performance results for the proposed QPS.