Compact MIMO Antenna For 5G Mobile Terminal

Multiple input multiple output(MIMO)antenna is widely used in 5G mobile communication terminals because it can use different paths in space to transmit data in parallel,which can improve the channel capacity of the system.On the other hand,mobile devices are usually small and contain many modules,leaving limited space for multi antenna systems.Compact integration of a large number of MIMO antennas will undoubtedly enhance the coupling between antennas.Therefore,how to eliminate the strong mutual coupling effect of compact integration has become the focus of current research.In view of the above requirements and challenges,this paper has done the following work:Firstly,a 5G broadband reconfigurable vehicular 4 × 4 MIMO antenna is proposed.The highlight of the design is the use of compact antenna structure to achieve broadband coverage.Specifically,the multi-mode resonance characteristics of the ring structure and the monopole and dipole modes generated by the parasitic elements are used to realize the-10 d B impedance bandwidth coverage of 1710-5000MHz(98.1% of the relative bandwidth)by combining the switch switching state.The antenna efficiency is higher than 73% in the working frequency band,which meets the requirements of practical engineering application.Secondly,an 8 × 8 MIMO antenna for 5G metal frame smart machine is proposed.The antenna is designed based on a dual patch element,which can be excited by in-phase and reverse phase signals simultaneously to generate two modes,namely,binary monopole subarray mode(mode 1)and coupled loop mode(mode 2).Through different path coupling energy cancellation,the isolation of the two modes can still reach a high level of 16 d B even though they share the same radiation structure.The antenna is processed and tested,and the test results are consistent with the simulation results.In the3.5GHz(3400-3600MHz)band,the antenna's physical efficiency is more than 33.6%,and the channel capacity is 39 bps / Hz.Finally,a compact 6 × 6 MIMO antenna for 5G terminal is proposed.The 6 × 6MIMO antenna is composed of four dual patch elements.According to the working principle,it is divided into two groups: the 4 × 4 MIMO antenna in mode 1 and the 2 × 2MIMO approximate omnidirectional antenna in mode 2,which are fed by two compact feeding networks with 90 ° gradual phase.The test efficiency of the antenna is between48% and 67% in the working frequency band,and its pattern has good omnidirectivity.The channel capacity in 3.5GHz band is 30.9 BPS / Hz,which is much higher than 4G 2× 2 MIMO capacity(about 10 BPS / Hz),so it is valuable for 5G communication.