| Antennas are the devices of coupling energy between the waveguide and free space, which can convert high-frequency currents in the transmitter circuit into electromagnetic waves radiating to the free space, or transform the electromagnetic waves from free space into high-frequency currents transmitting to the receiver, in return. Therefore Antennas are the very important parts of the wireless communication system, meanwhile they are the key components enhancing or limiting the overall system performance. With global promotion of the third-generation wireless communication technology, along with the fourth-generation wireless communication technology’s maturing each passing day, the coexistence of2G/3G/LTE multi-standard mobile communication networks has become an inevitable trend, therefore modern mobile terminals’ working band will also increase continuously, such as mobile phones, especially for the smart phones. In order to meet these requirements of multi-mode multi-band communications, recently mobile terminal antennas has been gotten more and more research and application.Based on the systematical study of technology of the internal mobile phone antennas’ miniaturization, multi-band and broadband proposed in this paper, simulation and optimization of built-in mobile handset antennas’ structure by using the HFSS software developed by Ansoft Corporation has been presented. Then Design examples of an internal monopole antenna and an internal loop antenna are given in detail. The proposed antennas design may have bright application prospects with the advantages of small-size, broad band, low profile and easy to conform. The research work of this master’s thesis mainly includes several aspects as following:Firstly, overviews of mobile communication system, and research background of the thesis, along with its research significance are mentioned roughly, following by a brief introduction of mobile phone antennas’ current research status.Secondly, discussions of antennas’ theoretical foundation are introduced, including the transmission line model of antennas’radiation and the electrical parameters describing antennas’ performance. Thirdly, theories of mobile phone antennas are proposed in detail in this part. To begin with, the common forms of internal mobile antennas as PIFA, monopole and loop etc. are introduced respectively; then detail presentation of methods of achieving internal antennas’ miniaturization, multi-band and broadband for the mobile phone. Applications are elaborated in the end.Fourthly, two design examples of built-in mobile phone antennas are given out respectively, including a monopole sample of working for the GSM/DCS/PCS/WCDMA operations and a loop sample for the GMS/DCS/PCS/WCDMA/LTE/WLAN band. Then simulation and optimization of these two antennas’ structure by using the HFSS are presented. An actual model of the proposed internal loop antenna is prototyped for testing, according to the design results. Measurement results and electromagnetic simulation ones are in good agreement, thus indicating that the proposed antenna design can meet the actual demands.Finally, after summarizing and reviewing the total work, give out the innovation of this paper, then put forward what are the unfinished and needing to be improved, and at last look forward to the future work plan. |
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