Análise de antenas refletoras circularmente simétricas com a presença de corpos dielétricos

Abstract

This work develops theoretical, analytical and numerical tools for solution of electromagnetic scattering from bodies of revolution, composed by perfect conductors and dielectrics, such as reflector antennas with radomes. Accurate analyses of these structures are performed through algorithms based on electric and magnetic integral equations, numerically evaluated by the Method of the Moments. The formulation is validated through several tests where the results are compared with the respective analytical solutions. This work investigates only omnidirectional double-reflector antennas with radomes, although the technique allows analyses of several types of axially symmetric reflector antennas consisting of dielectric and conducting materials. It is important to stress that the feed structure is considered in the antenna analyzes, preventing inaccuracy problems associated to the use of spherical wave sources to excite the reflector antenna. Some innovative aspects are presented, as the numerical evaluation of the integrals inthe method of moments solution, and the addition of dielectric materials in the analysis of large structures. It should be also pointed out the superficial equivalent currents are representated by triangular basis functions, which guarantees a good representation for current behavior throughout all surfaces of the bodies of revolution, and produces relatively simple integral equations.