Research And Design Of New Wideband MIMO Antennas

In recent years,with the rapid development of radio communication technology and the successful popularization of 4G technology,people have more and more stringent requirements on the performance and size of antenna.Multi-input multiple-output(MIMO)technology has the advantage of regarding the multi-path radio channel with the transmitter and receiver as a whole to optimize,so as to achieve high communication capacity and spectrum utilization rate.MIMO technology is a kind of near-optimal diversity to the spatial and temporal congregation and technique of interference cancellation,making it receive more and more attention in recent years.The U.S.Federal Communications Commission has released a 3.1-10.6 GHz bandwidth as Ultra-wideband(UWB)in 2002,a new type of wireless Communication technology,which has many advantages including wide bandwidth,high-data-rate wireless transmission,high capacity,and low-power consumption.The combination of UWB technology with MIMO technology,the use of space multipath,parallel transmission of multiple signals,can obtain obvious multiplexing gain and diversity gain,and achieve a stable signal transmission in distance.Isolation is one of the most important performance indicators of MIMO antennas,achieving high isolation and small size is also a challenge.In view of these problems,it is necessary to study the principle of reducing coupling of MIMO antenna elements,and design a new type of MIMO antenna to perform well in isolation,bandwidth,efficiency,pattern,dimension and so on.The main contents of this thesis are as follows:1.Based on the research status and historical background at home and abroad,this thesis introduces MIMO technology and reconfigurable technology,and briefly introduces the radiation principle of antenna,several important performance indexes and relevant calculation formulas,what's more,the basic design requirements of UWB MIMO antenna are also pointed out.2.A compact four-element ultra-wideband MIMO antenna is designed in this thesis along with very high isolation,dual polarization and notch structure,which can work in two states and is smaller in size.For convenience of application,trapezoidal slot is added to the antenna patch,and then the notch structure is realized and the WLAN signal of 5.2GHz and 5.8GHz can be perfectly covered.3.A multi-purpose ultra-wideband MIMO antenna is proposed and designed,which can realize multi-purpose by deleting the antenna specific structure so as to realize the transition of the antenna working frequency band from ultra-wideband to dual-pass to single-pass.4.Based on the reconfigurable technology,an ultra-wideband MIMO antenna with four elements is designed.By introducing a reconfigurable structure into the MIMO antenna to realize the transition of the different functions.5.The research work of this thesis is summarized and the prospect of future follow-up development is put forward.