A Coplanar Waveguide Fed Tri-Band Antenna Based on Circular Ring Structure

A compact coplanar waveguide fed tri-band planar antenna based on circular ring structure is designed and simulated with a size of 25.6x25.6x1.6mm(3). This antenna system is composed of four closed circular ring structures, a microstrip feedline, and a planar ground structure, in which each adjacent ring is connected by a small rectangular patch into a closed integral structure. The -10dB impedance bandwidth of the radiation patch is 110MHz(2.44-2.55GHz), 370MHz(3.11-3.48GHz) and 2010MHz(4.04-6.05GHz) and the corresponding center frequency is 2.53GHz,3.37GHz and 5.23GHz respectively. By using trident microstrip feed line and the modified ground structure to from a better impedance match. The radiation pattern of the antenna has consistent omnidirectional, and dipole characteristics at each resonant frequency, which has useful performance for Worldwide Interoperability for Microwave Access and Wireless Local Area Network applications.