A characteristic mode solution of the parallel plate-fed slot antenna

In this paper the characteristic mode theory is used for the computation of the receive and transmit mode aperture field of the parallel plate-fed antenna. In the transmit case the input region has the form of a waveguide carrying a single mode wave with electromagnetic characteristics that are different from those of the output region. The output region is considered to be free space. In the receive case the structure is excited by an incident wave which can be either a transverse electric (TE) or a transverse magnetic (TM) plane wave.