Gain Enhancement Mechanisms in Circularly Polarized FSS‐Embedded Meander Monopole Antenna

ABSTRACT This paper describes the design and implementation of a dual‐layer frequency selective surface (FSS) based dual‐band high‐gain circularly polarized (CP) meander‐shaped monopole antenna for the applications of Wi‐Fi and C‐band. To achieve the final configuration, the design process involves several steps: designing the meander‐shaped antenna, modeling the FSS, circuit analysis, and practical realization. The antenna prototype (electrical dimension: 0.333 λ₀ × 0.266 λ₀, λ₀ at 2 GHz and physical dimension of 50 × 40 mm 2 ) comprises a meander‐shaped strip and a 3 × 3 matrix dual layer periodic FSS embedded under the antenna structure without disturbing the impedance bandwidth. The low‐cost FR4 dielectric substrate is used to design both the antenna and FSS layer. Initially, only the antenna part was designed, which yielded −10 dB impedance bandwidths (IBWs) and 3‐dB axial ratio bandwidths (ARBWs) of 1160 and 600 MHz in the lower band, and 560 and 700 MHz in the upper band, respectively. Without an FSS structure, the peak gains of the antenna are 3.6 dBi (lower band) and 3.8 dBi (upper band). The proposed FSS‐based antenna is fabricated and measured in the microwave test bench. The measured results show 3‐dB ARBWs of 350 MHz (2.35–2.7 GHz) and 600 MHz (3.9–4.5 GHz) with LHCP waves. The measured peak gains are 8 dBi in the lower band and 8.5 dBi in the upper band. With small tolerance, the measured results agree with simulations.