Three‐dimensional analysis of patch antenna by bergeron's method

Abstract

Abstract Recently, extensive efforts have been expended in research and development of patch antennas which are small in size, lightweight and not very thick. In these antennas, the effect of the near field on the far field characteristics cannot be ignored. The former is affected in turn not only by the antenna element but also by the shape of the structure on which the antenna is installed. This near field has a complex field distribution which is dependent on the three‐dimensional structure and the medium conditions of the system. A systematic analysis in which the three‐dimensional structure and the medium conditions of the system are given rigorous consideration is indispensable. In this paper, a rectangular patch which is a basic form of the patch antenna is analyzed by the Bergeron method in terms of the three‐dimensional time response of the near field. Based on the aperture distribution of the electric field thus obtained, the far field is computed by Fourier transform. A method is proposed for efficiently deriving the far field in the Bergeron method. By comparison with analytical solutions, the validity of the fundamental treatment is verified. Further, by taking advantage of vector analysis, the electric field near the patch is expressed in a vector form for both the linear and circular polarizations. The spatial and temporal evolution of the field and the change from the near field to the far field are exhibited. Also, by means of the representation of the Poynting vector, the energy flow important for understanding the radiation characteristics of the antenna is depicted. The fundamental characteristics of the patch system are thus obtained.