Multi-antenna System For 5G Multi-mode Terminal

Now, wireless communication network environment has become a mixture of different kinds of heterogeneous networks. As a result, the development and exploitation of multi-mode mobile terminals has aroused worldwide interest in the wireless communication field. Thus, multi-mode and multiband smart phone antenna is a prerequisite requirement for present and future terminal devices, especially those with MIMO(multiple-input–multiple-output) system included. Furthermore, because of the demand for faster data transmission well beyond the 4G standard, some countries and regions have already defined their very own fifth generation(5G) wireless standards. Therefore, mobile terminal device with massive MIMO antenna array operating in 5G frequency band is presently a good candidate for future 5G operation. In view of this, in this article, the multi-antenna system for 5G multi-mode terminal is designed and investigated.Firstly, the basic knowledge of MIMO design is studied in this paper. the basic antenna design which is widely used in mobile phone and the realizing methods of miniaturization, broadband are analyzed. In view of the mutual coupling between MIMO antennas, some decoupling technologies for mobile phone are investigated.Secondly, a multi-antenna module with 2 4G antennas and 8 5G antennas is proposed. The 4G antenna could cover 824-960 MHz and 1710-2690 MHz operating bands, Here, a combination of protruded ground and NL techniques are applied into this antenna, so that enhanced isolation can be achieved for this 4G antenna module. The proposed 5G array is a bending monopole strip capable of covering 3400–3600 MHz. In an 8×8 MIMO system, the 5G antenna module has shown good ergodic channel capacity of approximately 40 bps/Hz.Thirdly, another 10-port(2 4G antennas and 8 5G antennas) multi-antenna module is proposed. a matching circuit is loaded at the feeding port to broaden the bandwidth in the lower bands, meanwhile, the mutual coupling in the lower bands is weakened by introducing a neutralization line. the 5G antenna is in the form of PIFA which could achieve higher efficiency, thus obtain higher ergodic channel capacity.Finally, a 12-port multi-antenna module is presented. The 4G-antenna has a volume of only 40×5×4.5mm3 and the two 4G antennas is placed at the top and bottom thus good isolation is achieved. The 5G antenna module have 8 slot antennas and 4 microstrip antennas, due to the orthogonal polarization, good isolation between microstrip antennas is obtained. meanwhile, the more antennas of 5G antenna module the higher ergodic channel capacity is acquired.The bandwidth, isolation, antenna efficiency, envelop correlation coefficient(ECC) of the three proposed multi-antenna module satisfy relevant standards.