Intermediate field of an impulse-radiating antenna

Methods for evaluating the intermediate field are examined. The contour integrals for thin-wire TEM aperture distributions can be expressed in closed form. Other types of TEM fields are also of interest (e.g., for coplanar plates). It is suggested that the aperture need not be a circular disk (e.g., a semicircular disk, as in a half impulse radiating antenna). It was assumed that the TEM fields on the aperture are propagating parallel to the aperture normal. This need not be the case. One can assume that the aperture fields take the form of a TEM plane wave propagating in other directions. The results apply to only one part of the waveform, the "impulsive" part. For a reflector impulse radiating antenna one needs to include the prepulse associated with the TEM field.