Controlling Resonances for a Multi-Wideband Antenna by Inserting Reactive Components

Abstract

A novel method is proposed to control the resonance frequencies of an antenna for multi-wideband operation. The parallel addition of reactive components to an antenna shifts the resonance frequencies without increasing the size of the antenna. These resonance frequency shifts can be analyzed by observing the voltage difference via an approach based on an open-circuit transmission line. The designed antenna has 180 MHz (940-1120 MHz) and 630 MHz (1970-2600 MHz) bandwidths under VSWR = 2.5 : 1 with a high radiation efficiency at dual-band. The lower and the higher bands of the antenna provide coverage for Global System for Mobile communications 900 (GSM900), Universal Mobile Telecommunications System 2100 (UMTS2100), Wireless Broadband (WiBro) and Bluetooth.