| Summary: | 博士 === 國立中山大學 === 電機工程學系研究所 === 106 === In this thesis, MIMO antennas in the metal-framed smartphone for 2 × 2 LTE LB and 4 × 4 LTE M/HB MIMO operations are presented. All antennas are only disposed at the short edges of the smartphone, and acceptable isolation and low envelope correlation coefficients (ECCs) can be obtained with no external decoupling structures. Moreover, all gaps used to separate different antennas are disposed away from the short-edge corners so that the user’s hand holding effects can be significantly decreased. At first, the design with two LTE antennas for 2 × 2 LTE MIMO operation is presented. The two antennas are disposed at the top and bottom edges of the smartphone, respectively. Both antennas can cover LTE L/M/HB. Then, the second design with four LTE MIMO antennas disposed at the same short edges is presented. Two of the four antennas can cover LTE L/M/HB, and the other two antennas can cover LTE M/HB. The four antennas can thus be applied for 2 × 2 LTE LB MIMO and 4 × 4 LTE M/HB MIMO operations. Finally, in order to easily tune the antenna’s LB to cover whole LTE LB bandwidth with small variations in the antenna’s LTE M/HB, the third design with six LTE MIMO antennas is presented. The six antennas are also only disposed at the top and bottom edges of the smartphone, with a ground clearance of 5 mm only. Four of the six antennas can cover LTE M/HB, and the other two antennas can cover LTE LB. In the six-antenna design, acceptable isolation between two nearby LTE M/HB antennas can be obtained owing to the decoupling structure of the LTE LB antenna disposed therebetween. The six antennas can therefore be applied for the 2 × 2 LTE LB and 4 × 4 LTE M/HB MIMO operations. Finally, the six-antenna design is applied for the large- display-panel smartphone with a narrower ground clearance of 2 mm only. Results of the MIMO antenna performances with such a very narrow ground clearance are discussed.
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