Investigations of a bidirectional antenna using a probe excited rectangular ring

The investigations of a bidirectional antenna using a probe excited rectangular ring are presented in this paper. The dyadic Green function approach is used. The electromagnetic fields in a rectangular ring antenna due to a probe excitation is derived for computing the equivalent magnetic and electric current densities. Then, the far field radiations are expressed as a superposition of the field from two apertures (an aperture in ±z direction). The effects of a probe on the features of rectangular waveguide are illustrated as normalized equivalent current densities with respect to the equivalent magnetic current of dominant mode (TE₁₀). The radiation pattern and directivity of single aperture (an aperture in +z and -z direction), two apertures, are characterized as antenna parameters. The probe length (l), ring width (a), ring height (b), and ring length (c) are selected based on the condition that provide the maximum directivity.