Analysis of aperture antennas in inhomogenous media

[摘要] The object of this report is to calculate the admittance andthe radiation pattern of aperture antennas fed by waveguides of arbitrary cross-section and radiating into dielectric slabs, whose constitutive parameters may be functions of position along the direction normal tothe slab faces.For a given aperture field distribution the antenna apertureadmittance and the radiation field are expressed here, for the first time, in terms of two auxiliary quantities directly related to the plane wave reflection and transmission coefficients of the dielectric slab.These quantities are the input admittance of the dielectric slab and the ratio of the total electric field amplitude transmitted at one end of the slab to the transverse field at the other, both calculated for plane waves as a function of incident propagation direction. This approach introduces a great simplification in the solution of the problem,particularly in the case of an antenna radiating into an inhomogeneous dielectric slab.A simple and powerful method has been devised for the computation of the input admittance of an inhomogeneous dielectric slab as well as for the electric field ratio. In this case the impracticability of obtaining analytical results has necessitated the use of numericaltechniques.Examples of the application of the theory to typical dielectric slabs are given and the results are discussed.

[发布机构] University:California Institute of Technology;Department:Engineering and Applied Science

[关键词] Electrical Engineering