Experimental Verification of Gain and Bandwidth Enhancement of Fractal Contoured Metamaterial Inspired Antenna

Abstract

In this work, a 2.5 GHz fractal contoured square microstrip antenna with four ring metamaterial structure, hereon referred to as optimized metamaterial inspired square fractal antenna (OMSFA), has been presented. This paper is an extension to the previously designed OMSFA [4] and aims to experimentally verify the enhanced gain and bandwidth of this antenna. The design and simulation of the proposed OMSFA was accomplished by using Ansys HFSS (v18.2). The end-to-end antenna spread area is 23 mm x 23 mm on a 46 mm x 28 mm x 1.6 mm FR4 substrate (εr = 4.4). The simulated OMSFA was fabricated using Nvis 72 Prototyping Machine and measured in an anechoic chamber facility using vector network analyzer. The antenna resonates with the deepest return loss at S11 of -39.5 dB in a broad bandwidth of 2.53 GHz from 2.265 GHz to 4.79 GHz with experimental verification. The OMSFA provides an enhanced gain of 8.81 dB at the desired frequency of 2.5 GHz. The simulation and experimental results of resonance, gain and radiation pattern are found to agree maximally. The fractional bandwidth offered by this proposed antenna is 72.28%. The experimental validation confirms enhanced gain-bandwidth performance in a wide resonance band. Hence, the OMSFA is well recommended for wireless and energy harvesting rectenna applications.