16. Comparative Analysis of TE₀₁ Mode Excitation Methods in Circular Waveguides

The axisymmetric magnetic modes of the circular waveguide are known for the anomaly of their low attenuation at higher frequencies. This is due to the low intensity of the electromagnetic field near the walls of the waveguide. Moreover, because of this fact, it is very difficult to excite these modes by common methods like using the electric and magnetic dipoles, slots, loops, etc. Insertion of such devices into the waveguide usually leads to distortion in the required mode field structure and, thus, inability of its excitation. The second problem is the fact that the axisymmetric magnetic modes are not the fundamental ones of the circular waveguide; and this demands the necessity of mode filtering and the complex analysis of the excitation devices. The main goal of this article is to describe and compare the effectiveness of various methods for excitation of the TE₀₁ mode in a circular waveguide. The advantages of the mode with respect to other types of waves propagating in the circular waveguide are discussed briefly. Each of the devices under consideration was modelled and the simulation results are given. Advantages and disadvantages of the devices are considered. Then, a comparative analysis of results of the numerical simulation is given.