Beam Steerable Fabry Perot Cavity Antenna Using Liquid-Based Metamaterial

Abstract

Beam steering antennas play a pivotal role in various applications such as wireless communication, satellite communication radar systems, etc., enabling the dynamic control of electromagnetic radiation. Conventionally, beam steering has been achieved through mechanical methods and phased arrays. Lately, many novel concepts have been used to achieve beam steering, which can provide better control of radiation characteristics and affordable solutions comparable to conventional techniques. These include the use of dielectric lenses, beamforming circuits and metamaterials. In this thesis, a reconfigurable metasurface-based approach is presented to achieve cost-effective beam steering with a compact antenna size. A partially reflective metasurface at an appropriate height over a patch antenna operating at 8 GHz is placed to form a Fabry-Perot cavity between these two reflectors, leading to constructive interference to improve the gain of the antenna. To achieve beam steering from the broadside to an offset angle, a liquid-based 9 × 9-unit elements metasurface is employed. This metasurface incorporates liquid channels on Polylactic acid (PLA) to create a phase gradient and effectively steer the beam. Filling these water channels with various configurations resulted in beam steering angles of -26° to 30°, 30° to 32°, and 28° to 31°, all while maintaining a -10dB impedance bandwidth and achieving a gain of over 8 dBi. To validate this innovative concept, a prototype is fabricated, and the measured results are compared with those obtained from software-based simulations. The measured results closely match the simulated data, demonstrating the feasibility of this system for radar and wireless communication applications.