Presentation Information
[C-12-27]A 24-GHz-Band Varactor-Tuned LC-Resonant Phase Shifter in 180-nm CMOS Technology
◎Koki Nakazawa1, Kyoya Takano1 (1. Tokyo University of Science)
Keywords:
phase shifter,5G,CMOS,LC resonator,FR3
Beamforming technology is essential in 5G and beyond communication systems, requiring phase shifters for precise phase control. However, conventional phase shifters suffer from a limited phase tuning range, especially at high frequencies. This study proposes a 24-GHz phase shifter using LC parallel resonant circuits composed of MOS varactors and inductors. The proposed circuit utilizes the rapid impedance variation of an LC parallel resonator near its resonant frequency. As a result, a small change in varactor capacitance produces a large phase shift at 24 GHz, enabling a wider phase tuning range than conventional designs. In addition, the circuit consists only of passive components and requires no DC power consumption. To verify the effectiveness of the proposed method, circuits with and without LC resonators were compared. A configuration with two LC resonators increased the phase variation by 21.3° compared with the conventional structure. The proposed phase shifter was designed and fabricated using a 180-nm CMOS process. Simulation results achieved a phase tuning range of 279.8° at 24 GHz, while measurements confirmed a phase tuning range of 258.86°. These results demonstrate that LC parallel resonance is an effective technique for realizing a wide phase tuning range in 24-GHz phase shifters