Analysis of dielectrically-loaded wire, strip and patch antennas using the method of moments

As an extension of the authors´ earlier work on the modelling of the surface current distribution over conducting surfaces of arbitrary shape (see IEE Conf. on Antennas and Propagation, Eindhoven, vol.1, p.369-73, 1995), the analysis of any arbitrary antenna geometry in the presence of an inhomogeneous dielectric body was evaluated using a method of moments procedure. The method can accommodate cases where the antenna is attached to, or is inside, the dielectric body. The solution was constructed by using the principle of the volume polarisation currents theorem. The antenna geometry may include any arbitrary surface shape (closed or open surfaces), strips and wires. The surface was modelled by rectangular and triangular patches while the strips (corresponding to their dominant current) were modelled by the same surface patches or by segments which included the discontinuity at the edges. A rigorous formulation for the attachment of wires and strips to the surface was used. Linear basis functions were used on the patches and the segments. The weighting functions were chosen to be the same as the basis, thus the solution was of Galerkin type. The dielectric was modelled by small rectangular volumes. A set of three uniform basis functions was used for each volume. Three delta weighting functions at the centre of each volume were used, giving a point-matching solution