| Mobile communication has developed from the first generation of analog communication to today's LTE 4G communication.However,it is still difficult to meet the requirements of rapidly growing user base and high-speed data transmission.Therefore,5G communication emerged.In November 2017,the Ministry of Industry and Information Technology of China announced the division of 5G frequency bands,which is expected to be officially commercialized by 2020.As an important component of the mobile terminal equipment,antenna needs to cover more frequency bands and wider bandwidth to realize the compatibility of terminal multi-network communication formats.In addition to meeting the use function,users also put forward higher requirements on the appearance of the equipment.The metal frame and full screen of the equipment make the area occupied by the antenna greatly reduced.In this thesis,three mobile terminal antennas are designed according to the requirements of miniaturization and multi-band.The main contents are as follows:1.A multi-antenna system integrating WWAN/LTE/5G bands is designed.The antenna can cover 698-960 MHz and 1710-2690 MHz by coupling feeding technology and multi-resonant mode of feeding branch and ground parasitic branch.In addition,in order to improve the channel capacity of the antenna system,six antenna elements operating at 3300-3600 MHz and 4800-5000 MHz are designed.2.A frequency reconfigurable antenna with narrow clearance width is designed.Two diodes are added to the antenna structure.By adjusting the two states of the diodes,the antenna can operate in three states.The antenna can cover LTE700/2300/2500,GSM850/900/1800/ 1900/UMTS2100,3300-3600 MHz and 4800-5000 MHz.3.An antenna with metal frame is designed.The metal frame is used as a part of the antenna in the antenna design.The antenna area on the dielectric substrate is reduced,the clearance area of the designed antenna is only 65×5 mm2.The antenna bandwidth can cover 698-960 MHz,1710-2690 MHz and 3300-3600 MHz. |
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