Research And Design Of Dielectric Waveguide Filter And Duplexer

The advancement of communication technology has brought a lot of convenience to people,but at the same time,it also puts forward high requirements for signal transmission rate,bandwidth,and spectrum utilization.As an indispensable part of the signal transmission process,the research of filters and duplexers is very important.Dielectric waveguide filters and duplexers use special materials with high dielectric constants,which are a type of filters and duplexers that have emerged in recent years.Dielectric filters and duplexers have the characteristics of high Q value,low insertion loss,and have the advantages of miniaturization and low cost.It is becoming the mainstream in modern mobile communication systems.This thesis mainly conducts the research and design of dielectric waveguide filters and duplexers for the 5G band.The research results are as follows:1.A fourth-order dielectric waveguide filter is designed.The operating frequency band is3.24GHz-3.44 GHz,and the return loss is <-20 d B.The basic dielectric properties of the filter design is a special ceramic material with a dielectric constant of 20.5.The design frequency is based on the5 G frequency band.The dielectric cavity is the basic structure,and the coupling size is changed by adding a tuning resonator hole.This fourth-order dielectric waveguide filter adopts the cross-coupling design of the CT structure,and introduces an operating zero at the low end and the high end of the operating frequency band to enhance its out-of-band suppression capability.The return loss obtained from the actual measurement is less than-12 d B,and the overall performance curve is more consistent with the simulation curve.2.A fifth-order dielectric waveguide filter is designed.The operating frequency band is3.24GHz-3.44 GHz,and the return loss is <-20 d B.Based on a dielectric material with a dielectric constant of 20.5,combined with a cross-coupling structure,a transmission zero is introduced at the low end and high end of the operating frequency band to enhance its out-of-band suppression capability.The simulated return loss is less than-20 d B,which meets the standard.Compared with the fourth-order dielectric waveguide filter designed in this thesis,the out-of-band suppression capability is improved.3.A dielectric waveguide duplexer is designed.The operating frequency bands are3.24GHz-3.44 GHz and 3.48GHz-3.68 GHz,return loss <-10 d B,isolation <-20 d B.The design material is a material with a dielectric constant of 20.5.A common cavity is designed to connect the upper and lower filter channels of the duplexer,and cross-coupling technology is used in it to improve the filtering capability of the duplexer.The simulated return loss of the dielectric duplexer can be controlled to <-12 d B,and the isolation is <-20 d B;the operating frequency band of the actual measured dielectric duplexer is stable at the designed frequency band,and the return loss of the low-frequency channel is <-7.5d B,the return loss of the high-frequency channel is <-10 d B,and the test result is consistent with the simulation result performance curve.