Angularly stable frequency selective surface for the gain enhancement of isolated multiple input multiple output antenna.

A metasurface is highly useful for improving the performance of patch antennas and reducing their size due to their inherent and unique electromagnetic properties. In this research work, we design a wideband bandstop reflector‐based frequency selective surface (FSS). It consists of a periodic array of circular shape metallic rings with four stubs. The FSS unit cell resonates over a frequency band from 7.2 to 9.2 GHz and has excellent stability under different polarizations and incident angles. A microstrip patch‐based isolated multiple input multiple output (MIMO) antenna is designed that operates over a frequency band of 7.9GHz to 8.7 GHz. The MIMO antenna and FSS are printed on the one face of a substrate. The radiation performance such as gain and directivity of the antenna is improved due to parasitic radiation of the surface and coherent‐ superposition of energy in the far‐field, between the antenna and FSS unit cells. Where the other parameters such are efficiency, radiation pattern and isolation are well preserved. The designed structure shows low complexity during fabrication. The simulated and experimental results confirm the predicted antenna performance and gain enhancement. [ABSTRACT FROM AUTHOR]