Design and Analysis of Frequency Agile Multi-Dielectric Stacked Circularly Polarized Holographic Metasurface Antenna

Abstract

This study presents a mathematical characterization of circularly polarized (CP) impedance-modulated metasurface antennas (MMAs) using single to multi-layer dielectric configurations for frequency reconfiguration. Inspired by the principles of optical holography, a 50×50 array of subwavelength metallic unit cells (2500 elements) is patterned on the top surface of a grounded dielectric substrate to generate a highly directive CP beam at (θ,φ)=(0∘,0∘) within the Ku-band. Frequency reconfiguration is achieved by varying the number of dielectric layers while keeping other antenna parameters constant. Theoretical modeling is provided for multi-layered dielectrics of equal thickness, and the design of single- and double-layer MMAs is detailed. Adding dielectric layers alters the effective relative permittivity (εr) and the total surface impedance (Zsurf ), enabling frequency agility. The proposed MMAs demonstrate an average gain of 20.5 dB with an axial ratio (AR) below 2 dB at their respective operating frequencies. Simulated two- and three-dimensional radiation patterns, AR, and S11 (in dB) are presented to validate the frequency reconfiguration capability of the multi-layered MMA structure.