A modified magnetic field formulation for aperture antennas

A novel integral boundary formulation, for determining the surface current density, the near and far-zone fields due to arbitrarily shaped conducting bodies in the presence of a known primary source is used to solve problems related to aperture antennas. A surface electric charge density is used as another equivalent source, in addition to the usual fictitious electric current density, so that a Modified Magnetic Field Integral Equation (MMFIE) can be derived to simulate the field outside the body. This approach allows the expansion of both unknown sources by means of two sets of subdomain-type pulse functions without causing inconsistencies or anomalies in the solution obtained by the method of moments (MM). Results for a cube show the validity of the MMFIE; examples of applications to rectangular truncated waveguides and flanged waveguide/coax adapters are reported