Reconfigurable antenna based on liquid crystal (LC) technology

Abstract

A reconfigurable antenna based on liquid crystal technology is presented in this paper. It comprises of a 1×4 microstrip patch antenna array, LC-based inverted microstrip line (IMSL) phase shifters, and RF-feeding and biasing networks. Nematic LC (N-LC) cell is used as tunable substrates for both the microstrip patch antenna array and the phase shifters. The dielectric tensor of N-LC is controlled a DC or low-frequency AC bias voltage. The microstrip patches are used as waveguide radiating elements while the LC-based IMSL phase shifters are used to steer the main beam. The RF signal coupled between the phase shifters and microstrip patch antennas are guided and then radiated from the top face of the microstrip patch antennas. As a proof of concept, the beam steering capability of the reconfigurable antenna is demonstrated by steering the main beam to −27°, 0 and 27° at 14.5 GHz and the frequency tuning capability is demonstrated by changing the frequency from 15.9 GHz at 0V to 14.3 GHz at 10 V, a tuning range of 10%. Comparisons with measurements are provided in order to validate the proposed numerical approach and illustrate the potential use of LC's as tunable materials in microwave and millimeter-wave frequencies.