| Handset antenna is a kind of electron device, it can realize the function of radiation. As an important part of the communication system, it arouses widely attention. As the high speed development of wireless communication system integration, there’s a trend for antenna with both miniaturization and highly performance. But there’s a contradiction between miniaturization of the antenna and high performance of it such as bandwidth, gain and efficiency. And this will be a challenge for handset antenna designers; there must be a balance between the two aspects. The exploration of practical miniaturized antenna, overcome its defects and improve the performance, so as to be used in every aspect of wireless communication could be the target of antenna designer. And this is also the research key point of antenna research and design.In this paper, base on the research status and research fronts of antennas and antennas for handset, establish the model for multiband slot antennas, and adopt meander line method, matching network method, metal frame adoption method, and finally realize the miniaturization. By adoption of multiple slots and matching network, realize the enhancement performance of bandwidth, gain and efficiency. Research on different parameters of antenna, compare the experimental and simulated results. Research on the theory of Balun, and adopt double symmetrical balun to realize the reduction of the common mode current on the outer surface of the coaxial cable, discuss the directive radiation based on metamaterial, and also the space gradient metamaterial cloak, it could be a future research area for the reduction of radiation for human body.This paper mainly includes the following several aspects:(1) First of all, research on the basis of antenna as well as antenna for handset, and introduce the electrical parameter such as radiation pattern, directivity, gain, radiation efficiency, input impedance and bandwidth. Introduce the radiation principal, radiation area division as well as the solution for the radiation field, give the development of handset antenna, performance parameter, the hand or head effect for the antenna, electrically small antenna theory, and the band requirement for handset antenna as well as the size, establish the basis for research and design for the handset antenna.(2) Base on experiment, manufacture and test, research on the impedance characteristic, bandwidth, multiple resonate point and the adjustment method of slot antenna, give the influence factor for the physical characteristics such as radiation pattern, electric current distribution, gain, radiation efficiency etc. Reduce the area of the slot antenna, and made it more practical with good performance.(3) Base on Babinet Principal, derived the electromagnetic theory and impedance transformation relationship for the complementary antenna (slot antenna) of dipole antenna. Based on the equivalent circuit and slot on an idea infinite conductor, derive the adjustment method for the slot antenna and the basic impedance matching method. Base on geometry theory of diffraction, explain the corrugated ups and downs on the radiation pattern. Give the basic design principal for slot antenna and propose the design method suitable for handset. Establish the model for slot antenna, and the simulated, test and the manufacture have also been made for the model. The smith chart, return loss, gain, radiation efficiency, radiation pattern, current distribution have also been analyzed and discussed. Every parameters satisfy the design performance requirement.(4) Considering the metal frame and other metal mobile phone components (such as Speaker or Camera, etc), as part of the antenna, design and manufacture of aperture (slot) antenna with width of15.5mm. Through the comparison between the simulation (simulation software:HFSS11) and the actual test results, the design of antenna can be covered GSM850/GSM900/DCS1800/PCS1900/UMTS2100five wave band, and it has good return loss, radiation pattern, the current distribution, as well as the high efficiency and gain, meet the standard five band antenna requirements. Research on the slot Antenna as balanced antenna with reduced hand effect, and compared the balanced antenna and unbalanced antenna with the hand effect, discuss adding Balun on coaxial cables to reduce cell phone motherboard surface current, so as to reduce the hand to influence on the performance of the Antenna. |
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