Propagation Of Hybrid Modes Research Articles

Transverse tranśmission theory for multilayer planar microwave circuits

AbstractTransverse transmission concepts in the Fourier transmission domain for multilayer planar transmission medium are presented. This complete transverse transmission theory (TTT) is found to be a superset of different Fourier‐transform‐based numerical techniques widely used in guided wave analysis, namely the modematching method and the spectral‐domain approach. The features of the theory are: the expansion of field quantities in longitudinal section (LSE/LSM) modes, the concept of rotation of the transverse field vectors, and a comprehnsive algorithm using recursive matrix standard form. It is shown that the mode‐matching method and spectral‐domain approach are generally equivalent except for the last step of imposing the final boundary conditions, and can therefore be summarized in a unified theory within the framework of TTT. In addition, a new parameter, the polarization coefficient, has been introduced to describe the field polarization of the guided wave in a quantitative manner. It is believed that the present theory will help us to gain more insight into hybrid mode propagation in multilayer planar circuits.

Analysis of waveguiding properties of traveling-wave semiconductor laser amplifiers using perturbation technique

Abstract The polarization sensitivities of traveling-wave amplifiers (TWAs) can be analyzed by determining the modal gain coefficients for different propagating modes. We applied the perturbation method to introduce a new technique for the calculation of these gain coefficients, which avoids the use of the optical confinement factor. It was found that this technique was particularly useful in deducing the gain dependence on polarization for hybrid mode propagation. Using the proposed technique, we discovered that the refractive index distribution has a significant effect on the polarization sensitivities of hybrid modes in TWAs, especially in buried heterostructures (BHs). This is a promising method in designing polarization-insensitive TWAs.

Eigenvalues of propagating waves in a circular waveguide with an impedance wall

The paper determines the eigenvalues and conditions of propagation of hybrid modes inside a circular cylindrical waveguide with an impedance wall. The analysis allows for different longitudinal and transverse impedances on the walls. A general characteristic equation is derived from which the corresponding characteristic equations for circular cylindrical waveguides with a perfectly conducting wall, a corrugated wall or a dielectric lined wall can be obtained. Finally, it is found that the propagation of hybrid modes in circular waveguides with large radii is independent of the surface impedance.

Corrugated waveguide with helically continuous corrugations

The cylindrical hybrid mode propagation and radiation characteristics have been theoretically analyzed, and corresponding experimental investigations have been carried out for a corrugated waveguide with helical anisotropy. Under the influence of helical corrugation the plane of polarization of the hybrid mode is found to rotate slowly as it moves along the guide. The frequency dependence of the plane of polarization has been studied for such waveguide feeds of given length.

Hybrid-Mode Analysis of Microstrip by Finite-Element Methods

A numerical analysis is presented in terms of finite elements of hybrid-mode propagation in closed microstrip. Two modes with zero frequency cutoff are described; one is a quasi-TEM mode and the other a surface mode. Also investigated is a third mode which corresponds to the lowest order waveguide mode in the absence of the strip.