A Small Size Three-Band Multi-Functional Antenna for Lte/GSM/Umts/Wimax Handsets

Abstract

Abstract-In this paper, a three-band antenna with small size 50 × 15 × 0.8 mm 3 is developed. The multi-broadband antenna consists of strip-1, strip-2, Br-1, Br-2 and S-strip. The lengths of strip-1, strip-2 are close to λ/4 at 680 MHz, 850 MHz and λ3/4 at 2.04 GHz, 2.55 GHz, respectively. S-strip is close to λ at 5.2 GHz 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: 680 MHz, 850 MHz, 2.04 GHz, 2.55 GHz, 3.7 GHz and 5.2 GHz. There exists electromagnetic coupling (EMC) among them. As a result of the effect of the structure, three wide-bands are produced: 660-1050 MHz, 1.60-3.75 GHz, and 5.25-6.50 GHz.That is, the operation band covers full LTE700/2300/2500(1710-2690 MHz)/GSM850/900/(680 MHz-960 MHz) GSM1800/1900/WiMAX3.5 GHz (3400 ∼ 3650 MHz)/5.4-GHz (5250 ∼ 5850 MHz)/UMTS (1710-2170 MHz). The return loss is better than −6 dB. The peak gains also satisfy the requirement for practical application.

Small-Size Coupled-Fed Two Opposite-Direction Spiral Branches for Handset Antenna

“…To realize the characteristic, a monopole structure may be an interesting candidate owing to its simple working mechanism, flexible adjustment modes, high integration with active devices, etc. Thus, several printed monopole coupled configurations for mobile phone have been proposed [2][3][4][5][6][7][8][9]. In [2], an on-board coupled-fed monopole antenna was presented, which consists of a feeding strip and a distributed inductive shorted strip.…”

“…The antenna achieves a seven-band WWAN/LTE operation covering 824-960/1710-2690 MHz frequency ranges and occupies a size of 15 × 29 mm 2 , but LTE700 band is not covered because it is difficult to obtain LTE700 band in an electrical small antenna. Similarly, several planar printed coupled-fed monopole antennas with multi-band operations are presented for ultra-slim mobile handset applications in [3][4][5][6][7] and use monopole coupled fed way to realize broad band operation, but these antennas have a large no-ground area of generally larger than 15 × 50 mm 2 . A 3-dimension monopole coupled-fed structure was also proposed for covering 698 ∼ 960 MHz and 1710 ∼ 2690 MHz bands [8], but the antenna has a large no-ground space of 24×60 mm 2 and three-dimensional structures, which may not be appropriate when integration and slimmer design is concerned.…”