Research And Design Of Dielectric Waveguide Filter

In 2019,since the Ministry of Industry and Information Technology of our country has delegated 5G commercial licenses to various operators,5G has officially entered our daily life,and for a long time in the future,5G communication technology is at the forefront,and 5G technology has put forward higher requirements in signal transmission rate,spectrum utilization and low latency.Dielectric waveguide filters made of high dielectric constant ceramic materials are becoming the mainstream of 5G base station filters because of their high Q value,low loss,small size and easy integration.According to the comprehensive design of dielectric waveguide filters,the following research and design are carried out:1.The comprehensive theories of traditional filter and generalized Chebyshev type filters are described,the calculation and simplification process of coupling matrix in filter synthesis are analyzed,the design formulas of rectangular waveguide filters are introduced,the limitations of Cauchy method and several improvements of Cauchy method in the extraction process of coupling matrix are proposed,and several mapping forms of space mapping algorithm are briefly described,which provides a theoretical basis for the design and optimization of dielectric waveguide filters later.2.Based on the comprehensive theory of Chebyshev type filters,two highly selective dielectric waveguide filters suitable for 5G frequency bands are designed,and the designed fourth-order and sixth-order dielectric waveguide filters adopt the topology of one pair of quadrupole and two pairs of quadrupole,respectively,so that a pair of transmission zeros and two pairs of transmission zeros are generated on both sides of the near resistance band,respectively.At the same time,by coupling parameter extraction technology and combining a space mapping algorithm,each parameter of the filters is optimized,which greatly shortens the design and optimization cycle of the filters.3.According to the existing rectangular simple mold and a ceramic material with a dielectric constant of about 43 in the laboratory,the structures of two S-band miniaturized dielectric waveguide filters were designed with the help of HFSS,and according to its structural parameters,the above ceramic material was used for dry pressing,pre-sintering,grinding,perforation,sintering and metallization preparation processes,and dielectric waveguide filter samples were made.The electrical performance parameters were tested with a vector network analyzer,and the filter sizes were only 8mm×16mm×5.2mm and 8mm×24mm×5.2mm,respectively,and there was a gap between the measured results and the simulation,and the reasons for the gap were analyzed in detail from the production process of the dielectric waveguide filters.