Research Of Balanced Filtering Antenna And Filtering Antenna Array

In rencent years,filtering antennas have been generally concerned with the demand of mobile communication equipments growing rapidly,which drives the progress of mobile communication technology and wireless communication technology.The feature of this component is the integration design.The advantage of this design is to reduce the loss brought by cascade connection.The second characteristic is it can decrease the dimension of the component,which is important in the requirement of miniaturization.Filtering antenna as a necessary part of many mobile systems has get a great development.The range of application becomes wider,such as intelligent home furnishing and wearable components,and the electromagnetic environment turns more complicated,thus higher performance of the filtering antenna is necessary,such as better electromagnetic compatibility,better gain.In the RF front-end,balanced filter has good electromagnetic compatibility,which can suppress environmental noise effectively.The balanced filtering antenna conbines the advantage of banlanced component and filtering antenna.antenna array has a high gain;and filtering antenna array can improve gain and enhance bandwidth.The main work of this paper is arranged as follows:Firstly,a microstrip balanced filtering antenna is designed.At first,a balanced filter is designed to ensure the performance of the integrate designed balanced filtering antenna.In order to ensure the out of band suppression of the balanced filter,a ?-shaped resonator is designed to introduce several transmission zeros;and ?-shaped resonator can adjust the resonant frequency conveniently,increasing the design flexibility.Then the the patch antenna is designed by loading the L-shaped slots to achieve good impedance matching.Return loss of the Balanced filter antenna reaches 20 d B,and the common-mode rejection is more than 25 d B,which can meet the requirement of performence.Secondly,a new balanced filtering antenna is proposed.The new balance filter antenna just relies on the even mode resonant frequency to achieve very high common-mode rejection.Under the common mode signal,the resonant is at the even mode resonant frequency exactly,the resonant frequency of the common-mode has a great difference with the differential-mode resonant frequency.Therefore,the component obtains a good common mode rejection.Because the component doesn't load stub,so the dimension can be effectively reduced simultaneously.Through simulation,the common-mode rejection reaches about 40 d B.The meansurement reasult is good agree with simulation reasult.At last,a microstrip filtering antenna array is presented,The traditional antenna array has a problem of narrow bandwidth.In this paper,the antenna array is regarded as a resonator of the filter,utilizing this design concept improves the bandwidth of the antenna array,and reduces the dimension of the antenna array filter by topology optimization.