Multiband Antenna Design

The development trend of the mobile phone is intelligent, ultra-thin, large screen and the integration of multiple communication systems. These features of the smart phone not only give users a convenience but also bring unprecedented challenges to the mobile phone antenna design. The electrical performance of mobile phone is depends largely on the performance of mobile phone antenna, and thus the research and design of high performance mobile antenna has important practical significance.Firstly, the history, the trends and the challenges of the mobile phone antenna are introduced. The bandwidth, the quality factor Q and the gain of the mobile phone antenna are analyzed, and also, the effect of the length of the ground on antenna designing is presented.Secondly, different features between planar inverted F antenna and the planar monopole antenna are analyzed and compared. The technology of multi-frequency in antenna designing is discussed. Then a planar inverted-F antenna and a planar monopole antenna are designed to verify some of the conclusions.Thirdly, two ultra-wideband mobile antennas are designed in this paper. Owing to the use of the coupling feed, one of the antennas can provide two wide bands for LTE700/2300/2500/GSM850/900/DCS1800/PCS1900/UMTS2100operation bands, and the other antenna can generate two wide resonant modes, covering GSM850/900/DCS1800/PCS1900/UMTS2100/LTE2300/2500operation bands. The designed antenna has planar structure and, therefore, low production cost. Finally, the simulated and measured results are given, which obtain good agreement.Finally, a MIMO antenna for DCS1800/PCS1900/UMTS2100/LTE2300/2500MIMO operations in LTE communication system has been presented in this paper. The proposed planar antenna element occupies only a size of15×20mm2. The high isolation between the two antennas is obtained. Finally, good radiation characteristics over all the operating bands have also been presented.