Researchs Of Microwave Passive Circuit Based On Substrate Integrated Waveguide

Substrate integrated waveguide (SIW) is a synthetic rectangular waveguide formed by the top and bottom metal plates of a dielectric slab and two sidewalls of metallice via-holes. It has some advantages such as high Q and high power capacity, low profile, low cost, easily being integrated on planar circuits. This dissertation gives a detailed study on the design theory and technology of high-performance SIW filters, including a transversal filter, a source/load-multiresonator cross coupling filter and two dual-mode filters. Also, a coupler based on half-mode substrate integrated waveguide is studied. It is summarized as follows:Firstly, the operation principle of SIW circuits is systematically expounded. The equivalence between substrate integrated waveguide and rectangular waveguide are introduced. In addition, their propagation performance is compared. Then, the loss of substrate integrated waveguide is analyzed. And what's more, the transitions between substrate integrated waveguide and other guided wave structures are studied.Secondly, several innovative single-mode substrate integrated waveguide filters are proposed. To the author's knowledge, the prototype theory of transversal resonator filter is applied by the author to the design of SIW filter for the first time. The proposed filter has properties of doublet and modified doublet, and it can obtain one or two transmission zeros. These two transmission zeros can be placed below or above the passband simultaneously, or one can be placed below and the other above the passband. Then a substrate integrated waveguide folded symmetric resonator filter with source-load direct coupling is realized, and the number of its transmission zeros is same with the order of the filter. At last we design a source/load-multiresonator cross coupling SIW filter. It is realized by introducing the mixed cross coupling in modified trisection filter, and it has flexible frequency selectivity.Thirdly, the SIW dual-mode filters are studied, among which two SIW dual-mode filters are proposed. The degenerated resonant modes of their resonators are perturbed by the slot lines and metallic via holes, respectively. According to author's knowledge, it is the first time to use slot line to perturb the degenerated modes of SIW dual-mode filters. The proposed filters can realize one or two transmission zeros, and it has small size, low insertion loss and high stopband rejection.Finally, a half-mode substrate integrated waveguide directional couplers are studied. The characteristics of the half-mode substrate integrated waveguide are studied, the design principles of cruciform substrate integrated waveguide directional couplers are discussed, and a cruciform half-mode substrate integrated waveguide directional coupler is proposed.