A Frequency-Reconfigurable Dual-Band Nematic Liquid-Crystal Reflectarray Antenna With Angular Beam Separation for Satellite Communication

Abstract

This paper presents a frequency-reconfigurable dual-band nematic liquid-crystal (LC) reflectarray antenna with angular beam separation for satellite communication. Dual-band operation at 12 and 28 GHz is achieved through voltage-controlled reconfiguration of the LC layer. In the proposed design, the reflectarray is illuminated by a feed antenna along boresight, and the reflected main beams are steered to 45° at 12 GHz and 30° at 28 GHz. This angular beam separation helps mitigate the inter-band interference issue commonly encountered in conventional dual-band reflectarray antennas. Simulated results demonstrate gains of 22.5 and 29.8 dBi at 12 and 28 GHz, respectively, with projected-aperture efficiencies of 43.3% and 35.2%. The corresponding sidelobe levels are 15 and 17 dB. To validate the design, a prototype was fabricated and experimentally characterised. The measured gains are 22.1 dBi at 12 GHz and 28.98 dBi at 28 GHz, corresponding to projected aperture efficiencies of 39.4% and 28.8%, respectively. The gain deviations from simulation are only 0.4 and 0.82 dB, mainly attributable to fabrication tolerances. The good agreement between simulation and measurement validates the proposed design and confirms its potential for dual-band satellite communication applications.