A triple-band multi-functional antenna for LTE / GSM/ UMTS/ WiMAX handsets

In this paper, a three-band antenna with small size 50×15×0.8 mm3 is developed. The multi-broadband antenna consists of the strip-1, the strip-2, Br-1, Br-2 and S-strip. The lengths of strip-1, strip-2, are close to λ/4 at 680MHz, 850MHz, and λ3/4 at 2.04GHz, 2.55GMHz respectively. S-strip is close to k at 5.2GHZ and λ3/4 at 3.7 GHZ. In addition, two tuning stubs Br-1 and Br-2 connected to strip-2 can further improve the impedance matching. Then six key resonances are excited: 680MHz, 850MHz, 2.04GHz, 2.55GHz, 3.7GHz and 5.2GHz. There exist electromagnetic coupling (EMC) among them, and as a result of the comprehensive effect of the structure, three wide-bands are produced: 660-1050MHz, 1.60-3.75GHz, and 5.25-6.50GHz. That is, the operation band covers full LTE700/2300/2500(1710-2690MHz)/GSM850/900/ (680M-960M) GSM1800/1900/WiMAX3.5G (3400~3650MHz)/5.4-GHz (5250 ~5850 MHz)/ UMTS (1710-2170MHz). The return loss is better than -6dB. The peak gains also satisfy the requirement for practical application.