Determination of Surface Currents on Circular Microstrip Antennas

Godaymi, Wa'il A.; Mohammed, Abdul-Kareem Abd Ali; Ahmed, Zeki A.

doi:2012.12.4.260

J. Electromagn. Eng. Sci > Volume 12(4); 2012 > Article

Journal of Electromagnetic Engineering and Science 2012;12(4):260-270.
DOI: https://doi.org/10.5515/JKIEES.2012.12.4.260

Determination of Surface Currents on Circular Microstrip Antennas

Wa'il A. Godaymi¹, Abdul-Kareem Abd Ali Mohammed², Zeki A. Ahmed¹

¹Dept. of Physics, College of Science, Univ. of Basrah
²Atmosphere and Space Science Center, Ministry of Science and Technology

Abstract

This work aims to present a theoretical analysis of the electric and magnetic surface current densities of a circular microstrip antenna (CMSA) as a body of revolution. The rigorous analysis of these problems begins with the application of the equivalence principle, which introduces an unknown electric current density on the conducting surface and both unknown equivalent electric and magnetic surface current densities on the dielectric surface. These current densities satisfy the integral equations (IEs) obtained by canceling the tangential components of the electric field on the conducting surface and enforcing the continuity of the tangential components of the fields across the dielectric surface. The formulation of the radiation problems is based on the combined field integral equation. This formulation is coupled with the method of moments (MoMs) as a numerical solution for this equation. The numerical results of the electric and magnetic surface current densities on the outside boundary of a CMSA excited by $TM_{11^-}$ and $TM_{21^-}$ modes are presented. The radiation pattern is calculated numerically in the two principle planes for a CMSA and gives a good results compared with measured results published by other research workers.

Key words: Microstrip Antennas, Body of Revolutions