Research And Design Of Mobile Terminal MIMO Antenna

With the rapid development of wireless communication systems, the requirement for higher data transfer rate in mobile communication system is increasing dramatically, and limited spectrum resources have become a bottleneck in the process of development. Therefore, MIMO as a critical technology can enhance the efficiency of spectrum utilization without requiring additional bandwidth or transmission power in complex multi-path environments, which is regarded as the core technology of next generation mobile communication. In this paper, we mainly focus on how to design the antenna to meet the growing demand for mobile terminals having compact structure, multiband, and high isolation. Aiming at this problem, the main work in this thesis as follows:1. Based on the working principle of monopole antenna and inverted F antenna,each antenna element is folded into three-dimensional structure, which covers the surface of FR4 cube to reduce the size. The proposed eight-element MIMO antenna is composed of symmetric monopole antenna elements, inverted F antenna elements, and slits etched on the ground plane, which meets LTE1900, LTE2300, LTE2600 bands.The simulated and measured results show the isolations are more than 10 dB when the distance between antenna elements is 9.6 mm.2. Base on the antenna radiation pattern diversity, by optimizing the size of inverted F antenna elements, the structure of ground plane and the location of antenna elements, the antenna with band within 1.85-1.96 GHz,2.3 -2.7 GHz is achieved, and the mutual coupling between the elements are less than -10dB. This method without using decoupling structure simplifies the design of MIMO antenna.3. The mobile communication network has become a mixture of different networks; a hybrid antenna system is proposed in order to meet the multi-band needs.The antenna array composed of a 4G antenna element covering GSM850/900/1800/1900/UMTS2100, LTE2300/2600 bands, two 4G antennas meeting LTE1900, LTE2300, LTE2600 bands, and six 5G antenna elements operating at C-band (3400-3800MHz). At the same time, the good decoupling effects are achieved.