Determination of cutoff frequencies of simple waveguides using finite difference method.

摘要

Waveguides are used to transfer electromagnetic energy from one location to another. Within many electronic circles, waveguides are commonly used for microwave RF signals; the same principle can be used for many forms of waves from sound to light. They have been used in many technologies like acoustic waveguide speaker technology, high-performance passive waveguide technologies for remote sensing and communication, optical computing, robotic-vision, biochemical sensing and many more.;Modern waveguide technology employs a variety of waveguides with different cross sections and perturbations, the cutoff frequencies and mode shapes of many of these waveguides are ill-suited for determination by an analytical method. In this thesis, we solve this type of waveguides by employing the numerical procedure of finite difference method. By adopting finite difference approach with an application of eigenvalue method, we discuss about few different types of these waveguides in determining the cutoff frequencies of supported modes, and extracting the possible degenerate modes and their field distributions. To validate the method and its accuracy, it is applied to the two well known rectangular waveguides, viz. PEC Rectangular Waveguide and Artificial Rectangular Waveguide (consists of PEC and PMC walls) and compared with the analytical solutions.