Design of Circularly Polarized Beam Scanning Reflectarray Antenna at 100 GHz Based on Liquid Crystals

A liquid crystal (LC) based circularly polarized (CP) beam scanning reflectarray antenna is designed operating within the frequency range from 98 to 102 GHz. The antenna consists of a liquid crystal reflectarray and a polarization converter. The unit cell structure of the reflectarray is made up of three parallel dipoles put on a LC substrate. The polarization converter is placed above the reflectarray to achieve the circular polarization. The simulated results show that the proposed beam scanning CP reflectarray antenna realizes beam scanning capabilities between -20 degrees and -10 degrees while the gain reaches up to more than 13dB and the axial ratio keeps less than 3dB.