Characteristics of a slotted parallel-plate waveguide filled with a truncated dielectric

A slotted parallel-plate waveguide filled inside with a material which is truncated is analyzed. An integral equation is formulated for the slot electric field, and it is solved by the moment method. Data are presented for the slot electric field, a special aperture admittance, scattering parameters, and a far-field pattern. The special aperture admittance is a useful quantity in microstrip antenna design and is presented for various truncation lengths of the interior dielectric.