Contributions to guided wave theory [article]

Fook Loy Ng, University Of Canterbury
There are many forms of structure for the guiding of electromagnetic waves. A review of these forms is given by Barlow (1964). He describes the well established parallel-wire and coaxial lines, and hollow uniform waveguides. He also considers waveguides containing solid materials and gaseous plasmas, and beam and surface waveguides. This thesis is a report on investigations into the numerical computations of the propagation characteristics of three types of guiding structures namely, the hollow
more » ... namely, the hollow waveguide, dielectric loaded waveguide and the dielectric clad azimuthal surface waveguide. The numerical solution of the hollow waveguide problem is considered in Part 1. Chapter 1 contains a comprehensive review of the methods used for the solution of the waveguide problem. This complements the only presently available review, given by Davies (1972) who compares and discusses the relative merits of some current methods (finite difference, finite element, point-matching, integral formulations and conformal transformation). Some useful criteria established by Davies in his review for the comparison of methods are used in Chap. 1 (Sec. 1.3). Chapter 2 is concerned with the numerical solution of waveguides of arbitrary cross-section by the null field method which was developed by Bates (1969b). Accurate results are obtained and it is demonstrated that for shapes possessing sharp reentrant corners, the computational accuracy is improved by explicitly satisfying the edge conditions at these corners. The detailed numerical investigation provides the supporting evidence for the computational viability of the null field method. The complete point-matching method is derived from the null field method and it provides an insight into the straightforward point-matching method (Bates 1969b). Chapter 3 considers point-matching methods of solution. Results obtained using the complete point-matching method show that accuracies of about 0.1% are obtainable for waveguide cross-sections which are convex. Less accurate results are obtained f [...]
doi:10.26021/1437 fatcat:4wga6c2e3fakhndz55deo7m6rm