Technology Of Multi-Mode Miniaturized Antennas

With the increasing requirement of communication data transmission rate,mobile communication technology has developed rapidly in the past few decades.The rapid development of 5G technology has accelerated the research of terminal applications,including the indoor communication system and mobile terminal.For indoor communication antenna,the performances of miniaturization,low profile and broadband are the trend of development.For mobile terminal antenna,multiple antennas are located in a limited space,thus the isolation performance of MIMO antennas is the focus of attention.The innovation of 5G technology is a great challenge for antenna engineers.In this thesis,the designs of the indoor communication antenna and MIMO mobile terminal antennas are studied,and author's contribution is as follow:1.For indoor communication antenna,monopolar patch antenna is the most common form.In this thesis,a wideband monopolar patch antenna merged multi-mode with a simple structure is proposed by using the theory of cavity mode.The antenna consists of a circular patch and a concentric annular ring,which is coupled-fed by a T-shape monopole at its center.Three modes includingTM₀₂ mode of the circular patch,TM₀₂ mode of the annular ring and monopole mode of the T-shape monopole are excited.Three modes are merged together to realize a wideband characteristic.The proposed antenna has performances of wide bandwidth,high gain and low profile.2.For MIMO mobile terminal antenna,a new decoupling method is proposed to guide the design of high isolation MIMO mobile terminal antennas in this thesis.Multiple feeding ports are located at the same radiator.By properly designing the location of the feeding and shorting pins,using the method of adding parasitic branch and slot,different kinds of MIMO mobile terminal antennas are designed.The proposed antennas have high isolation performance in the working band.Through the distribution of the current on the antenna,it can be clearly seen that the current is mainly distributed on the side of feeding port.Thus,the high isolation performance of MIMO mobile terminal antenna designed in this thesis is verified.