Design And Fabrication Of Vertically Cascaded Substrate-Integrated-Waveguide Dual-mode Filters

With the development of modern microwave and millimeter wave technology, a combinationtechnology of microwave transmission technology microstrip line with traditional metal rectangularwaveguide named substrate integrated waveguide (SIW) have been widely applied by scholars andresearchers.This structure uses the metallichole in the dielectric substrate to achieve a field of thewaveguide propagation mode. SIW is between microstrip and dielectric-filled waveguidetransmission line, which take into account the advantages of traditional metal rectangularwaveguide and microstrip transmission line such as small size, low power cost, high Q value and itis very convenient to integrate SIW with the other microwave microstrip transmission structure.In this thesis, the transmission characteristics of the substrate integrated waveguide is studiedand introduced firstly. Then it describes how to use the equivalent of the traditional rectangularwaveguide to design substrate integrated waveguide cavity, and then through the introduction of aperturbation technique to design single cavity substrate integrated waveguide dual-mode band passfilter. In order to further improve the performance of the filter, the cascading technology of a singlecavity structure is analysised and designed, the vertical cascade structure of the two cavity aremainly designed. One is to use the slit in the metal layer shared between the upper and lower cavityto achieve a cascading effect, and the other is to use the metal through-hole between the upper andlower cavities to achieve a cascade of two cavities. After the design and simulation of these twostructures, both structures have been processed and tested. The measurement results show that thecascade structure used the slit has an insertion loss of-1.5dB at the center frequency of2.5GHz, therelative bandwidth is4%and the lowest passband S11reaches-15dB,out-band suppression reaches-40dB; the cascade structure used the the metal through-hole has an insertion loss of-2.3dB at thecenter frequency of2.5GHz, the relative bandwidth is4%and the lowest passband S11reaches-10dB, out-band suppression reaches-50dB。...