Miniaturization Design Of 5G Microwave Dielectric Filter

With the increasing development of wireless communication technology and the advent of 5g era,there are higher and higher requirements for the size and performance of communication equipment.The RF front-end device is the basis of wireless communication,in which the filter plays an important role,and its performance affects the whole RF system.Because the miniaturization of filter is often accompanied by the sacrifice of performance,how to maintain high performance while miniaturizing filter has always been the main direction of filter research.Because the miniaturization of filter and the development of coupling theory complement each other,especially in large volume cavity filter,the miniaturization realized by coupling theory is particularly obvious.Therefore,based on the coupling theory of filter and the structural optimization of filter,this paper designs several miniaturized dielectric filters suitable for 5g communication standard.Using a quarter wavelength resonator as the resonant unit,two patch coaxial monolithic filters are designed.The resonator is a typical TEM mode resonator,which has the advantages of stable field structure and wide frequency band.Due to its own structural characteristics,the dielectric surface has a metal shielding layer,which makes the arrangement more compact.In addition,the port design of interdigital silver layer is adopted in the design of coaxial filter,which increases the adjustment range of coupling between port and cavity and improves the flexibility of design.The designed six cavity laminated dielectric waveguide filter for 5g communication base station has a center frequency of 3.5GHz.Unlike the traditional dielectric waveguide filter,the cavities of the upper and lower dielectric blocks are coupled by etching windows to form a laminated structure.This structure can easily introduce cross coupling between the upper and lower cavities,and reduce the filter order under the same stopband suppression index,Thus further miniaturization.Compared with the traditional dielectric waveguide filter,the miniaturization degree is more than 25%,and the new laminated structure can reduce the contact area by half when the filter is integrated with PCB substrate.In order to meet the more stringent stopband suppression standard,a ten cavity waveguide filter with double CQ structure is designed in this paper,which can control the zero position of the near end and the far end of the passband at the same time.It is also suitable for 5g communication base stations.Due to the limitations of cross coupling theory,non adjacent resonant units are not easy to form cross coupling in many structures.In this paper,a direct coupled dielectric waveguide filter based on hybrid electromagnetic coupling is designed,and the zero position is controllable,which improves the practicability of the filter...