Programmable array antenna based on nematic liquid crystals for the Ka-band

Abstract

A programmable low-profile array antenna based on nematic liquid crystals (NLCs) is proposed. Each antenna unit comprises a square patch radiating structure and a tunable NLC-based phase shifter capable of achieving a phase shift exceeding 360° with high linearity. First, the above 64 antenna units are periodically arranged into an 8 × 8 NLC-based antenna array, and the bias voltage of the NLC-based phase shifter loaded on the antenna unit is adjusted through the control of the field-programmable gate array (FPGA) programming sequences. This configuration enables precise phase changes for all 64 channels. Numerical simulation, sample processing, and experimental measurements of the antenna array are conducted to validate the performance of the antenna. The numerical and experimental results demonstrate that the proposed antenna performs well within the frequency range of 19.5-20.5 GHz, with a 3 dB relative bandwidth of 10% and a maximum main lobe gain of 14.1 dBi. A maximum scanning angle of ±34° is achieved through the adjustment of the FPGA programming sequence. This NLC-based programmable array antenna shows promising potential for applications in satellite communication.