Sharif Digital Repository

In this thesis, two kind of Kirchhoff type equations are investigated. for each of them we prove existence and uniqueness of weak solution by letting hypothesizes on problems functions and initial conditions and using Faedo-Galerkin method and some theorems in functional analysis. It is should be mentioned that one of the problems has unique strong solution according to compactness theorems. In the nest step stability of these equations are investigated. for this purpose it is showed that total energy of systems will tend to zero as time goes to infinity. Furthermore at the end of each chapter numerical results are presented to illustrate accuracy of obtained theoretical results. Finally we... 

Today in the most microwave and millimeterwave systems, one or more filters are used due to interference and noise phenomena. Microwave filters are manufactured in different environments such as waveguide, microstrip and SIW. For military and satellite applications that high power handling and low loss are in preference, the only appropriate environment is the waveguide. Other priority which is more important in satellite application is the low weight and small size of the product; Because of that, the idea of dual-mode waveguide filter was proposed in the early 70 decade. These kind of filters are able to produce two poles in one cavity resonator, which can decrease weight and size of the...