An IQ Modulator-Based RF Phase Shifter

This paper presents a design of a radio frequency phase shifter based on an IQ modulator. In contrast to traditional phase shifter architectures, this design employs an off-the-shelf quadrature modulator featuring a wide operating frequency range and attractive power consumption to achieve phase-shifting functionality. The performance of the proposed approach is validated through a case study involving Analog Devices' AD8349 chip, and the measured results show a full 360° phase tuning range. The findings indicate that despite inherent performance deviations in IQ modulator IC for phase shifter design, these discrepancies can be effectively mitigated through calibration algorithms, facilitating precise phase control. This design offers advantages such as low cost, compact size, and broad operational bandwidth, making it suitable for applications like smart antennas.