Contents I. Introduction
The traditional structure of passive phase shifters offers advantages such as low DC power consumption and high linearity. However, in millimeter-wave systems, these phase shifters face challenges, including varying insertion loss in different phase states. Amplitude inconsistency among various phase states can negatively impact the beamforming performance of phased array systems. Previous research has explored passive switch-type phase shifters, [1] introduced a 5-bit passive phase shifter based on LC filtering, achieving a low phase variation but demonstrating an amplitude inconsistency of 6dB. In [2], a 4-bit switch-type phase shifter based on transmission lines was presented. Despite reducing the footprint of the phase shifter, it still did not address amplitude inconsistency. Recent studies have focused on mitigating amplitude inconsistency in phase states. Some approaches involve using variable gain amplifier (VGA) for amplitude consistency compensation [1]–[5], but this degrades the linearity of the phase shifter, introduces additional phase variation and extra power consumption, thereby impacting the overall performance of the phase shifter.
