Research And Design Of The Planar Filtering Antenna

Filters and antennas are two important components of the RF front-end circuit,and their performance and size play a decisive role in the normal operation of the entire communication system.In recent years,people have paid more and more attention to the miniaturization of communication systems,and spectrum resources have become more precious and subdivided.Because of the precious spectrum resources,researchers have put forward higher requirements for the high-frequency selectivity of antenna systems.In view of these problems,the integrated design of filters and antennas has shown great advantages,and has become one of the research hotspots in the field of antennas.In recent years,the continuously improved filter antenna theory has made it easier to apply to a variety of traditional antenna structure designs,and the development space is becoming more and more extensive.Therefore,this paper will study and design the planar filtering antennas with compact structure and good frequency selection characteristics.The main contents are as follows:First,introduce the current development status of the filter antenna at home and abroad,and explain the basic knowledge of the antenna and the filter and the main electrical parameters.Secondly,this paper proposes two filtering antennas based on the antenna and filter synthesis method.Firstly,the planar antenna structure is used to replace the last-order resonator of the filter to realize the design of the filtering antenna.In this design,the filter uses a split ring resonator,and then replaces the last-order resonance structure of the filter with a loop antenna of good radiation characteristics,and a filtering antenna is obtained.Then,based on the T-shaped open branch filter,the parallel microstrip line was used to feed the coupling,and the ?-shaped antenna structure was used to replace the last-order resonator of the filter to obtain another filtering antenna.The designed filtering antenna has a compact structure,good frequency characteristics,and excellent out-of-band rejection.Finally,this paper proposes two filtering antennas by using the method of loading filters in the feed structure of the antenna.Firstly,an antenna was designed by opening an asymmetric U-shaped slot on the ground plate,and then a filtering antenna was obtained by loading the filter of the interdigital coupling structure into the feed structure of the antenna.Then a traditional Vivaldi antenna was designed,and a T-shaped filter was loaded into the feedline of the Vivaldi antenna to obtain a filtering antenna.The obtained antenna has a flat passband frequency gain and a sharp band edge,which has both the antenna's radiation characteristics and the filter's frequency selection characteristics.