Perturbation Method for the Analysis and Optimization of Microwave Devices

A perturbation method for determining the parameters of microwave devices, such as admittance, impedance, and scattering parameters, is presented. Several types of perturbations are considered: variation of component parameters, differentiable variation of medium properties, thin film growth, and boundary shifting. The concept of power waves is generalized to nondiagonal and infinite-dimensional complex source impedance operators. Based on this concept, the radial waveguide concept is developed, and parameters that incorporate phase information are introduced for antenna characterization. These concepts and parameters enable the application of the presented method for solving a wide range of problems, including matching complex impedances and antenna optimization.