A compact uniplanar <scp>ultra‐wideband</scp> frequency selective surface for antenna gain improvement and ground penetrating radar application
Surajit Kundu
Abstract
A simple structured single layered frequency selective surface (FSS) that has unit cell size of 11 × 11 mm2, substrate thickness of 0.8 mm only and capable to work in a very widespread band from 0.001 to more than 17 GHz is proposed in this article. The FSS is competent to augment the gain of a UWB monopole antenna by 2 to 3.5 dBi when integrated at the back of antenna. The performances of “antenna-FSS” structure is evaluated by simulation and experimental measurement where good correlations are obtained. The integrated structure provides wide impedance band (S11 < −10 dB) from 2.82 to 19.94 GHz (more than 150%) with improved broadside radiation and high radiation efficiency profile. The transient and frequency domain characteristics of “antenna-FSS” composite structure are also evaluated in close proximity of diverse sub-surfaces such as dry sand, wet sand, wood and concrete where an almost unaltered impedance band profile, linear transfer function response and non-varying group delay responses are achieved which establishes the applicability of the composite structure in ground penetrating radar for low depth sub-surface scanning applications.