Radiation of slot antennas in a plane waveguide

Slot antennas hold a special position in antenna theory and engineering. Presently, the radiation problems of such antennas and calculation of their characteristics using different exact and approximate methods are of considerable interest. In this paper, radiation of longitudinal and transversal slot antennas placed on a perfectly conducting circular cylinder in a plane waveguide with perfectly conducting walls are considered. The problem is solved in the approximation of a thin slot and at the given distribution of the electric field along the slots. Solution of the problem for electromagnetic fields, radiation power and conductivity are presented in the form of a double series over the eigenfunctions of the perfect plane waveguide and the azimuth eigenfunctions of the cylinder. Such a representation is very convenient for numerical calculations. The numerical calculations of real and imaginary parts of the radiation conductivity are performed. The effect of geometrical slot, cylinder and waveguide parameters on the slot antenna characteristics is analyzed. It is mentioned that the radiation characteristics of antennas placed in free space and inside the waveguide are different.