本文介绍了一种基于K波段圆极化液晶相控阵（LCPA）的系统研究和验证，包括设计、空口（OTA）阵列校准和实验验证。该液晶相控阵包含16个移相辐射通道，每个通道由圆极化堆叠贴片和基于加载差分线结构的液晶移相器（LCPS）组成。由于其慢波特性，在液晶层厚度仅为5 μm的情况下，液晶移相器的最大相移范围超过360°，品质因数为78.3(°)·dB^-1。在此基础上，提出了一种基于相态遍历法的空口自动校准方法，该方法能够提取每个独立液晶相控阵通道的相位电压曲线。所提出的液晶相控阵剖面高度仅为1.76 mm，实验测得在峰值增益为12.5 dBic下实现了-40°~ +40°的圆极化波束扫描，扫描损耗小于2.5 dB。该液晶相控阵在25.5 ~26.0 GHz频带范围内同时具有反射系数低于-15 dB、轴比小于3 dB、波束偏移小于3°、增益波动小于2.2 dB的性能，总效率达到34%。该圆极化波束扫描低剖面液晶相控阵及其系统设计和校准方法在各种毫米波应用中具有广阔的前景。

This paper presents a systematic investigation and demonstration of a K-band circularly polarized liquid-crystal-based phased array (LCPA), including the design, over-the-air (OTA) in-array calibration, and experimental validation. The LCPA contains 16 phase-shifting radiating channels, each consisting of a circularly polarized stacked patch antenna and a liquid-crystal-based phase shifter (LCPS) based on a loaded differential line structure. Thanks to its slow-wave properties, the LCPS exhibits a maximum phase-shifting range of more than 360° with a figure of merit of 78.3(° )·dB⁻¹ based on a liquid crystal layer with a thickness of only 5 μm. Furthermore, an automatic OTA calibration based on a state ergodic method is proposed, which enables the extraction of the phase–voltage curve of every individual LCPA channel. The proposed LCPA is manufactured and characterized with a total profile of only 1.76 mm, experimentally demonstrating a scanned circularly polarized beam from −40° to +40° with a measured peak gain of 12.5 dBic and a scanning loss of less than 2.5 dB. The bandwidth of the LCPA, which satisfies the requirements of port reflection (|S₁₁|) < −15 dB, an axial ratio (AR) < 3 dB, beam squinting < 3°, and a gain variation < 2.2 dB, spans from 25.5 to 26.0 GHz. The total efficiency is about 34%, which represents a new state of the art. The use of the demonstrated low-profile LCPA to support circularly polarized scanning beams, along with the systematic design and calibration methodology, holds potential promise for a variety of millimeter-wave applications.