Abstract
Antenna theory is a mature subject that has been treated in recent years by most scientists and engineers in a highly cumbersome mathematical manner, and this makes the fundamental principles, and design parameters such as radiation resistance, directivity beamwidth and gain of antenna very obscured. In this paper electromagnetic wave theory of antenna is reviewed. The paper laid emphasis on the understanding and application of the electromagnetic theory to antenna, using appropriate Maxwell’s equations. As an illustration of the application of the theory, the radiation resistance of a loop antenna making use of radiation components of electric and magnetic fields is provided. The result shows that the radiation resistance, on which some useful characteristics of antenna depend, is a direct implication of Maxwell prediction that S = � (E x H).