Research On Functional Fusion Filtering Antennas Based On Multimode Patch

With the upgrading of wireless communication systems,the design size of RF devices has been further compressed,but the overall performance requirements continue to increase.Therefore,traditional single function devices have been unable to meet the requirements.Novel multiple function devices such as filtering antennas and duplexing filtering antennas can not only combine multiple functional devices together,but also improve the characteristics of gain and frequency selection while reducing the size.The research of the filtering antenna in this paper is mainly based on the multimode patch antenna.It makes full use of its different mode characteristics and combines the loading technology to complete the design of the filtering antenna with high gain and multiple radiation nuulls.The main work and contributions of this paper include the following two parts:Firstly,a high order mode filtering antenna design method is proposed to solve the problem of low gain of the fundamental mode patch antenna.Through the analysis of the patch antenna mode,the even harmonics around the TM₀₃ mode are effectively suppressed.In order to obtain low sidelobe levels and filtering characteristics,a solution is proposed that only uses slot loading technology without introducing additional circuits.And the equivalent circuit model of the model is proposed,each structure is fitted and analyzed,its port characteristics are basis for the fusion design of more functional devices.The test and simulation results are highly consistent,and fully prove the effectiveness of the design method.Compared with the filtering antennas in other literatures,the higher order mode filtering antennas have higher gain characteristics,with a single antenna gain of 11.86 dBi.Secondly,in order to improve the frequency selectivity of the filtering antenna,a duplexing filtering antenna with multiple radiation nulls is proposed.Through the analysis of the modes of the multimode patch antenna and the multimode resonator,the field distribution of each mode is obtained.Furthermore,different mode excitations are discussed in depth.A second order filter is formed in the operating band under odd mode excitation.Therefore,an equivalent model is proposed and combined with the coupling matrix theory for comprehensive design.Radiation nulls are formed on the sideband under even mode excitation.At the same time,the generation principle of the transmission zeros generated by the two channels is analyzed.From the test results and the design comparison with other articles,it can be seen that the duplexing filtering antenna in this paper has the main advantages of multiple radiation nulls and multiple transmission zeros.In summary,the high order mode filtering antenna provides a new idea for high gain design.The multiple radiation nulls duplexing filtering antenna improves the filtering characteristics while additionally integrating the duplexer function.In addition,the radiation nulls in this paper can be individually controlled,so it can be extended to other frequency bands,thereby increasing the application range in the communication system.