Compact Multi-layer Filters And Power Dividers Based On SIW Technology

With the rapid development of modern communication technology,radio frequency(RF)front-end systems are rapidly developing towards high integration,miniaturization,and low cost.As the important components of the RF front-end system,the performances of filters and power dividers have played an important part in the whole RF front-end system.Therefore,low loss,miniaturized microwave/millimeter wave technology is critical to the development of high-performance wireless communication system.Substrate Integrated Waveguide(SIW)is a new type transmission line of planar waveguide structure.SIW not only keeps the advantages of traditional waveguides,such as low loss,high-quality factor,high power capacity,self-consistent electrical and mechanical shielding;but also has the characteristics of light weight,low cost,and easy integration.Therefore,SIW can be widely used in the continuously developing microwave/millimeter wave integrated systems.Aiming at the hot topics and difficult problems in RF front-end circuit,this thesis is devoted to the analysis and design of several high-performance filters and power dividers based on SIW technology.The main research works are listed as follows:(1)Bandpass filters based on SIW-CSRR and SCSIR:These two filters with high selectivity and wide out-of-band rejection are designed for 5G applications.The center frequency and transmission zeros can be controlled independently by adjusting the parameters of the complementary split-ring resonators(CSRRs)and the short-circuit centered stepped impedance resonator(SCSIR),and then high selectivity and wideband harmonic suppression can be achieved.One two-order and three-order bandpass filters are designed respectively by using the typical coupling matrix theory.These works have been published in International Journal of RF and Microwave Computer-Aided Engineering and IEEE Asia-Pacific Microwave Conference(APMC).(2)Wideband power dividers based on microstrip-slotline-SIW coupling structure:Transitions based on microstrip-slotline-SIW coupling are used to achieve broad bandwidth.A three-port wideband power divider is designed based on TE₁₀ mode SIW,and fork-shaped microstrip lines are used to improve the output-matching bandwidths;a four-port balanced-to-single-ended power divider with common-mode suppression is designed based on TE₄₀ mode SIW.This work will be submitted to IEEE Transactions on Circuits and Systems II:Express Briefs.(3)In-phase/out-of-phase wideband power dividers based on TE40 mode SIW:TE₄₀mode SIW and multi-layer coupling structures are used to arrange all ports on the same layer.The T-shaped microstrip line is employed to realize the power splitting function.The large bandwidth was achieved by slot coupling.In addition,the in-phase/out-of-phase feature can be obtained by adjusting the locations of the microstrip stubs.The equivalent circuits and separation models are provided,while the basic design guideline and impedance matching method are given.This work has been submitted to IEEE Transactions on Circuits and Systems II:Express Briefs.