Multi-band Pass Filter Based On 5G Communication

With the rapid development of modern wireless communication systems,the application of new technologies such as WLAN,3G,and 4G can be seen everywhere in people's daily lives.However,with the passage of time,more and more communication devices are being accessed in the era of information explosion.The 5G communication system that is used for big data and large traffic is destined to become a future trend.According to the announcement issued by the Ministry of Industry and Information Technology,The two bands of 3.3GHz-3.6GHz and 4.8GHz-5.0GHz are used as the working frequency band of the 5G communication system.Because the multi-band communication is involved in the 5G communication system,the dual-passband filter will play a very important role in the 5G communication system.Firstly,after reading a lot of literatures,the thesis combed the development history of microwave filters and the development direction of filters from the beginning to the present,and then profoundly studied the design principles and methods of the twopassband filters mentioned in the literature.Designed two dual-passband filters for domestic 5G communication bands.After a detailed theoretical analysis of the loading method of the short-circuited branch and the loaded open-section branch by the odd-even mode analysis method,a double-passband filter is designed by using the parallel multiple resonators mentioned in the introduction.The two separate short-circuit branch-loading resonators are used to generate the passbands that need to be designed separately.Firstly,according to the target frequency point,the size and physical structure of the resonator are determined,and then the two short-circuited branch-loading resonators are fed simultaneously by the parallel coupling line to appropriately couple the resonators,so that the two branches are respectively loaded on the resonators.To form a desired target passband,in order to enhance the coupling,the design of the defect ground(DGS)is given in the parallel coupling,and the resulting double-passband filter return loss is 12.3dB and 25.1dB,respectively.Since there is no transmission zero between the two passbands of the first dualpassband filter designed,in order to achieve better out-of-band rejection,a two-passband filter is designed using two identical open-circuit intermediate-segment-loaded resonators.Device.In order to generate a transmission zero between the two passbands,a method of introducing a transmission zero at a signal from the input to the output is used to improve the out-of-band rejection,and then the structure of the interdigitally coupled microstrip line is added.Enhance the coupling to the resonator to obtain the response of the two passbands.The resulting passband of the first passband filter has an insertion loss of 0.36 dB and a return loss of 12 dB.The insertion loss of the second passband is 0.14 dB and the return loss is 26.5dB.