I. Introduction
Phased array antennas have been widely used in recent years due to the advantages like fast scanning speed, flexible beam control, and searching and tracking signals on moving carriers. In actual application scenarios, phased array antennas with the characteristics of miniaturization, light weight and low cost have attracted more and more attentions. In general, the antenna phase can be adjusted by electric control [1]–[4], light control [5] or mechanical control [6]. In terms of antenna materials, new materials such as liquid crystal and graphene have further enriched the design of the antenna [7]–[8].