| With the rapid development of the mobile terminal equipment,the consumers' demand for the function of the mobile phone is getting higher and higher.It's necessary for smart phone antenna to realize multi-band coverage.Besides,consumers' demand for beauty has led to the development of smart phone in the direction of thinning and metalizing.It is a new challenge for mobile phone manufacturers to realize the double demands of multiple bands and beauty at the same time.Therefore,it has great meaning to study how to design a multi-band antenna in a mobile phone with low profile and metalized.The first part of the thesis will give a comprehensive elaboration on the development history of mobile communication technology.We also will give the background and the current situation of mobile phone antenna at home and abroad.In the second part of this thesis,the basic knowledge of mobile phone antenna design will be introduced in detail.In addition,three kinds of common built-in mobile antennas are analyzed in theory: PIFA antenna,monopole antenna and loop antenna.Several common methods to realize multi-frequency technology in mobile antenna also are introduced in detail.In the third part of this thesis,two design schemes for the seven band monopole phone antenna based on the matching circuit are proposed.The common feature of the two schemes is that both of the monopole antennas are formed by the connection of metal patches and metal plates in the clearance areas on the dielectric plates.And the two antennas are all tuned by adding the matched circuit to achieve the multi-band coverage of the low profile ultrathin mobile phone.The first one named folded monopole antenna based on the matching circuit can cover two wide operating bands of 760-960 MHz and 1710-2690 MHz.The second mobile antenna can cover two wide operating bands of 820-960 MHz and 1700-2950 MHz.Then the antennas were fabricated and measured,the results show that the designed antennas have good performances.So the antennas are suitable for a new generation of ultrathin mobile phones.These antennas are worthy of use in practice.In the fourth part of this thesis,a metal frame mobile antenna with two slits is proposed.The antenna is fed mainly through the L-shape feed wire.By selecting three appropriate location positions and using the working principle of ring antenna,multiple resonant modes are produced.In the end,the antenna can cover 824-960 MHz and 1710-2880 MHz.Not only the antenna has an extremely simple structure,but also it can also meet the multi-band coverage of the phone's communication needs.It meets the requirements of 4G communication finally.In the fifth part of this thesis,a nove design scheme of fully enclosed metal frame smart phone antenna with irregular structure is proposed.The metal frame is divided into two parts by a feeding point and a ground patch.The antenna is tuned by a matching circuit and the different distances between the irregular structure and metal frame.The antenna can cover 790-990 MHz and 1700-2710 MHz finally.Then the antenna is fabricated and measured,the results show that the designed antenna has good performance.It meets the needs of practical engineering applications and can be well applied to the WWAN/LTE systems. |
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