Polarization-Insensitive Compact Antenna Integrated With Frequency-Selective Surface for Gain Enhancement and Sensor Feature

The polarization-insensitive integrated frequency selective surface (FSS) is developed in this work. An inverted G-shaped radiating patch manufactured on an affordable FR4 substrate, 1.6 mm thick, serves as the base, with overall dimensions of 30 × 35 mm2. It functions over various bands, with the design frequency of 5.8 GHz, attaining the broad fractional bandwidth of almost 74%. The antenna demonstrates strong performance, with a peak gain of 4.3 dBi and an efficiency of 85%. To enhance the performance of an antenna, the FSS layer is implemented beneath the microstrip patch. Demonstrating angular stability and independence of polarization over a range of incident angles is found by simulation and experimental analysis. The overall structure exhibits adequate angular insensitivity under both TE and TM modes and the proposed FSS is suitable in the sensing application, when a substrate materials placed over FSS, the monotonic reduction in resonant frequency is observed with increase in the dielectric constant of that material. Incorporation of FSS improves the peak gain of the antenna to 8.8 dBi. The proposed antenna is highly suitable for ISM band, C-band, Communications, and radar applications apart from this the proposed FSS is advantageous in sensor deployments.