Broadband µ-negative antenna using ELC unit cell

Abstract

A broadband printed monopole antenna is designed by using ELC (Electric Inductive–Capacitive) based metamaterial element for WLAN applications. The proposed antenna comprises single ring hexagon loaded with ELC metamaterial for broadband radiation. ELC is designed with a square loop nested inside the ring hexagon structure which is coupled by the small metal stub. By introducing ELC, it significantly improves the impedance bandwidth of the antenna due to unique EM wave property. The band characteristics of the ELC and its metamaterial property (negative permeability) are explained through waveguide setup method. The designed antenna involves with dimensions 30 × 30 × 0.8 mm3 and fabricated on a low-cost Flame Retardant-4 substrate having εr = 4.4 and tanδ = 0.02. It yields an impedance bandwidth of 2600 MHz (2.61–5.21 GHz) with a dual resonance of 3.21 GHz and 4.89 GHz, which is usable for WiMAX, C-band and WLAN applications. The measured far-filed pattern exhibits a stable pattern. The proposed antenna has many benefits, such as comprising compact size, simple structure, lower S11 (dB) and capable of broadband characteristics.