Planar three-band antenna for LTE/GSM/UMTS /WLAN/WIMAX mobile device applications

A planar triple-band antenna with size 40 × 18×0.8 mm3 for LTE/GSM/UMTS and WLAN/ WIMAX is developed in this paper. The antenna is constructed in four steps. The first step is named Antl. In one side of the substrate, a non-folded strip is connected with a ground plane and a rectangle patch at both end of the non-folded strip, respectively. Antl is fed by a T-strip, which is in the other side of the substrate. Ant1 generates two modes at 2.8GHz and 1.97GHz and is responsible for the operation band 1.25-3.65GHz. The second step is named Ant2. On the basis of Antl, the non-folded strip is changed into folded strip. Two new resonant modes at 680MHz and 5.8GHz are introduced. Ant2 is responsible for the operation band (660-1120MH), (1.71-3.85 GHz). The third step is named Ant3. On the basis of Ant2, two branches (Br-1, Br-2) are introduced. Br-1 and Br-2 are in the same side of Ant1 and connected with the ground plane. Then the operation band (5.15-6.17 GHz) is added on the basis of Ant3. The fourth step is named Ant4. A slot is etched from the rectangular patch, and the impedance is greatly improved in the three operation bands. As a result, a triple-band antenna covering the LTE700/ 2300/ 2500 (1710-2690 MHz)/GSM850/900/ (690-960MHz) /GSM1800 / 1900 / UMTS (1710-2170 MHz) / WiMAX3.5 GHz (3400 ~3650MHz) /5.4GHz (5250~5850MHz) is formed. The gain for the proposed antenna is 1.2-4.2dBi, and the radiation efficiency is about 67%-95%.