A Low Profile Button Antenna with Back Radiation Reduced By FSS

Abstract

In this article, a button antenna with a reflective frequency selective surface(FSS) is proposed to reduce its back radiation. The proposed antenna is low in profile, circularly polarized and designed for Wi-Fi and WLAN applications. The radiating element is made of copper sheet, while a transparent acrylic fibre sheet is used as a substrate. The antenna is fed by a coaxial line, and the FSS layer is designed onjeans material. The patch type FSS with split ring shape has also been designed to operate in the Wi-Fi and WLAN frequency band (5.250–5.S50 GHz) with the centre frequency of 5.51 GHz. The FSS reduces back radiation of the antenna by 4 dB. The antenna with FSS is fabricated, and a measured gain of 2. 9dBi is obtained that matches well with the theoretical value. The antenna is miniaturized by around 61.15% by the slits. To achieve circular polarization characteristic Defected Ground Structure (DGS) slots etched at the ground plane of the triangular patch. The measured impedance bandwidth is 190MHz, and the 3dB axialratio (AR) bandwidth is 160MHz, respectively.