Study of rotationally symmetric antenna with wider beamwidth

Abstract

Numerical analysis is carried out for the antenna consisting of a rotationally symmetric oblate spheroidal conductor connected below and above a circular patch antenna with its dielectric substrate truncated at the edges of the patch. By means of the equivalence principle, the exterior and interior of the antenna are separated as problems equivalent to the original one. The cavity model is used for the electromagnetic field model inside the dielectric material while the equivalent electromagnetic current flows at the dielectric aperture are expressed in terms of sums of the mode functions. The current at the conductor surface is assumed from the continuity condition of the current at the junction plane of the dielectric and the conductor. The magnetic field integral equation at the dielectric aperture and the electric field integral equation at the conductor surface are solved by Galerkin's method in order to derive the unknown coefficients contained in the equivalent electromagnetic currents at the dielectric aperture and the current at the conductor surface. For the case of a conductor height of 0, a circular patch microstrip antenna with its dielectric substrate truncated at the edges of the patch is fabricated and its input impedance is measured. As the conductor height is increased, the radiation beamwidth in the E plane is expanded. Since this antenna has a wider radiation beam than that of the circular patch microstrip antenna, it is useful as an antenna for mobile satellite communication terminals. © 2000 Scripta Technica, Electron Comm Jpn Pt 1, 83(11): 1–10, 2000