Novel Ultra-Slim Multi-Mode Planar Antennas For Mobile Phone Handsets

With the rapid development of mobile communication technology, mobile phone handsets have become the main communication tools, and been endowed with more and more functions. As a key component of a mobile phone, the antenna has to satisfy more wireless communication standards. Multi-broadband and planarization antennas for mobile phone are the emerging trend. Therefore, it is very practical to study the multi-mode planar antennas which can cover all the existing communication frequencies(LTE 700/2300/2600, GSM 850/ 900/1800/1900/UMTS, WLAN 2.4/5.2/5.8 GHz, Wi MAX 2.5/3.5/5.5 GHz). In this paper, we focus on how to cover all the frequencies of LTE/WWAN/WLAN/Wi MAX by using novel antenna structures.Firstly, we summarize the research background, significance and status of the subject. The related theory, performance parameters, designing techniques and test standards of a mobile phone antenna are also presented.Secondly, a biplanar antenna for LTE/WWAN/WLAN/Wi MAX handsets is proposed. Antenna miniaturization and multi-band/wideband operation are realized by using the meander lines,multi-branched technology and the two-strip configurations. The antenna has a total size of 125 mm × 65 mm × 0.508 mm, and covers four frequency bands(696-970 MHz, 1683-2700 MHz, 3070-3755 MHz and 4590-7604 MHz) for VSWR ≤ 3(Return loss ≥ 6 d B). The biplanar antenna for LTE/WWAN/WLAN/Wi MAX handsets can meet the international performance standards by adjusting the antenna structure and optimizing the related parameters, which is very suitable for applications in ultra-slim smart mobile handsets.Thirdly, the above antenna structure is so compact that there is no space for more frequency bands. Therefore, a uniplanar closed loop antenna is proposed on the basis of folded/CPW loop antenna. Two uniplanar closed loop antennas with slots and inductive branches are designed, respectively, which verify that the uniplanar closed loop antenna can be used to realize multi-band/wideband planar antennas.Finally, on the basis of the uniplanar closed loop antenna, a uniplanar antenna for LTE/WWAN/WLAN/Wi MAX/GPS handsets is proposed. This antenna has a total size of 145 mm × 60 mm × 0.508 mm, and covers three frequency bands(687-976 MHz, 1195-1246 MHz and 1423-7665 MHz) for VSWR ≤ 3(Return loss ≥ 6 d B). The uniplanar antenna for LTE/WWAN/WLAN/Wi MAX/GPS handsets can meet the international performance standards and has certain value for engineering application by adjusting the antenna structure and optimizing the related parameters.