Design of a T-Shaped Antenna Based on Characteristic Mode Manipulation for Metal-Framed Handset Application

Abstract

Recently, metal-framed handset antennas have aroused much attention due to their fantastic appearance and superior robustness. In this paper, a T-shaped antenna suitable for integration with a USB connector is proposed for metal-framed handset application by utilizing the theory of characteristic modes (TCM). Five eigenmodes, one for the lower band and four for the higher band, were merged by a T-shaped metal frame, a feed point, and two shorting pins, as well as three radio frequency (RF) switches so as to broaden the antenna's operating bandwidth. A prototype was fabricated in order to verify the design concept. Experimental results showed that the proposed antenna was able to cover bandwidths of 0.824-0.960 GHz (GSM band) and 1.710-2.690 GHz (DCS, PCS, UMTS, and LTE bands) with an acceptable radiation efficiency of up to 50% and satisfactory radiation patterns.