Research And Design Of Miniaturized Communication Components Based On Multilayer Dielectric

With the rapid development of wireless communication technology,the related industries represented by mobile Internet and Internet of things have risen rapidly.A large number of mobile communication terminal products appear in the daily production and life.Mobile terminal system realizes wireless communication by exploiting microwave radio frequency circuit.The filters and antennas play key roles in the process of signal sending and receiving.Therefore,the design of high-performance and miniaturized filters and antennas has always been a research focus in the field of wireless communication.In this thesis,based on multilayer dielectric structure,several filters with miniaturized and high performance characteristics and a high-gain filtering antenna loaded with metasurface transmitarray are realized by using low temperature co-fired ceramic(LTCC)technology.Firstly,in this thesis,a wideband filter and a dual-band filter are designed based on the structure of stepped impedance resonator(SIR)in multilayer dielectric.The folded SIRs are used in both filters to make the structure of the filters more compact.The wideband filter achieves cross-coupling through capacitance structure,and then introduces transmission zeros(TZs)on both sides of the passband,which improves the selectivity of the passband.The dual-band filter achieves cross-coupling through inductance structure,and then introduces transmission zeros between the two passbands,which improves the isolation of the passbands.Secondly,in this thesis,three miniaturized filters are designed based on the structure of substrate integrated waveguide(SIW)in multilayer dielectric.First of all,a miniaturized wideband filter with five quarter-mode SIW structures in multilayer dielectrics is constructed by vertical cascade coupling.What's more,a wideband filter with notch characteristic is realized by combining the one-third mode SIW structure with the coupled transmission line structure,in which the coupled transmission line structure produces notch characteristic,while the SIW resonator produces wideband filtering effect.Lastly,reducing the resonant frequency of the full-mode SIW resonator by capacitive loading can further reduce the size of the filter.The circular metal sheet embedded in the SIW cavity can realize capacitive loading.Meanwhile,a cross-coupled topology structure is formed between SIW cavities to introduce transmission zeros to improve the out-of-band suppression ability.Finally,in this thesis,a miniaturized filtering antenna operating at 28 GHz isdesigned based on multilayer dielectric structure.The antenna structure is mainly composed of SIW resonators and dielectric resonators.The structure of SIW cavity at the bottom produces filtering effect.The dielectric resonators at the top layer operate as 2×2 array antennas to obtain higher gain.In order to further improve the antenna gain,in this thesis,the theory of metasurface transmitarray is introduced and a metasurface structure with gradient phase characteristic is designed.The metasurface consists of two layers of dielectric and three layers of metal structure.By loading it directly above the filtering antenna,the maximum gain of the antenna can be increased by more than 10 dB.