Design of 1-Bit Circularly Polarized Electronically Scanned Reflectarray Antenna at 100 GHz Based on Liquid Crystals

In this paper, the design method for a circularly polarized one-bit electronically scanned reflectarray antenna working at 100 GHz based on liquid crystal (LC) is proposed. The phase shifting element supporting circular polarization is first designed and investigated. Under the control of the driving voltage, the reflection phase of the array element can be switched between 0 and 180 degrees with the change of the LC molecules’ state. Consequently, a circularly polarized beam scanning reflectarray is realized by the phase shifting elements periodically arranged on a plane and illuminated by a feeding horn antenna. Numerical simulations are conducted to demonstrate the reflectarray antenna’s performance. Results show that, with the one-bit phase shifting resolution, the antenna achieves the beam scanning range from -30 degrees to -10 degrees while the gain reaches up to more than 20 dB and the axial ratio keeps less than 3 dB.