| As a RF front-end component in wireless communication systems, antenna determines the quality of receiving/transmitting signals and the overall appearance of cellphone directly. Mobile phone need to cover GSM, DCS, PCS, UMTS, and LTE five basic models, more than forty frequency bands, so the procedure of design mobile phone antenna is a key process in the cellphone design industry. This dissertation gives an analysis and study of structure of mobile antenna and its electromagnetic characteristics. According to the demand of wireless application, three types of antennas have been studied and proposed.Firstly, a low profile multi-mode antenna using monopole and shorted loop is proposed for mobile communication applications, covering GSM 850/900/1800/1900 MHz, UMTS, and some mainstream LTE commercial bands. Another compact antenna that achieves the same multi-resonance coverage is designed by combining a monopole and parasitic structures.Secondly, the performance of a GPS/Wi-Fi/Bluetooth antenna is simulated and tested. Within 10 meters, the prototype system with proposed antenna can connecting to the hotspot successfully and GPS positioning time is less than 40 s. After that, a reconfigurable multi-mode mobile antenna is presented and analyzed. Design theory and process of antenna with the RF-switch is studied. Though control the on/off state of the switch, LTE 700 and GSM850/900 band can be covered.Finally, design method of antenna using metal frame environment of cell phone is analyzed. Considerations on feeding point and grounding point in engineering is studied. Then a multi-mode antenna with metal border involved in 791~960MHz, 1710~2170MHz, 2300~2400MHz, and 2500~2690MHz is projected.By combining simulation and measurement, the results show that the performance of the proposed antennas meets the design requirements and also proved the correctness of the design plans. |
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