Research On Miniaturized Substrate Integrated Waveguide Filter

In the era of Internet of everything and data explosion,more and more devices are connected to wireless communication systems.As the core component of channel selection in RF transceiver systems,filters have been extensively studied in terms of miniaturization,high selectivity,and wide resistance band.In this paper,based on the miniaturization design of substrate integrated waveguide（SIW）filter,the high selectivity,wide resistance band and multifunctional integration of the filter are investigated respectively.We propose a half-mode SIW（HMSIW）filter with independently controllable transmission zero position,a dual-mode folded SIW（FSIW）filter with high selectivity and wide rejection band,and a dual-band filter balun based on a circular SIW resonator.The main research and innovation points of this dissertation are as follows:1.An HMSIW filter with flexible transmission zeros is proposed.The design utilizes the higher-order mode of the resonator to introduce the transmission zeros.The characteristics of the HMSIW rectangular resonator under the perturbation via-holes and perturbation slotline are investigated.The TE₃₀₁ mode of each perturbation HMSIW rectangular resonator will be used to realize the passband of the filter,and the TE₁₀₂ and TE₃₀₂ modes will be used to realize the two transmission zeros of the filter.By changing the position of the perturbation via-holes or the length of the perturbation slotline,the position of one transmission zeros can be flexibly controlled,while the position of the other transmission zeros remains unchanged.Based on the above analysis,a linear coupling structure is proposed to design an HMSIW filter with independent control of the transmission zeros position,which provides a new idea for the introduction and control of the transmission zeros of the traditional SIW filter with simple design and independent control.2.A dual-mode FSIW filter with high selectivity and wide stopband is proposed.The characteristics of the bi-directionally folded sector SIW resonator and the bi-directionally folded rectangular SIW resonator are investigated.The constraint functions of the first several resonant modes in the bi-directionally folded sector SIW resonator and the bi-directionally folded rectangular SIW resonator are derived,which provides a fast and efficient method for the analytical calculation of the resonant frequencies and physical dimensions of the two resonators.The bi-directionally folded sector SIW resonator with dual-mode characteristics and the source-load（S-L）coupling introduced by the non-resonating node（NRN）can achieve two position-controlled transmission zeros to improve the passband selectivity and out-of-band rejection.Based on the bi-directionally folded sector SIW resonator and the bi-directionally folded rectangular SIW resonator,a fourth-order dual-mode filter with high selectivity and wide rejection band（upper rejection band bandwidth:>1.65@20d B）is proposed,and combined with the complimentary split-ring resonator（CSRR）,a fifth-order dual-mode filter with high selectivity and wide stopband is constructed without increasing the filter area.3.A compact dual-band filtering baluns using perturbed SIW circular resonator is proposed.The characteristics of the dual-band circular SIW resonator are studied,and the corresponding port positions are designed by analyzing the electric field to add the function of differential output on the basis of dual-band filtering.The design of arbitrary order is realized based on the laminated structure of the dual-band circular SIW resonator,which is compact and simple to design,and the bandwidths of the two bands are independently controllable.Based on the above design structure and the coupling matrix synthesis method,the second-order dual-band filter balun and the third-order dual-band filter balun are synthesized to verify the implementability of this scheme in the actual expansion process.