TRANSIENT RADIATION FROM ANTENNAS: EARLY TIME RESPONSE OF THE SPHERICAL ANTENNA AND THE LATE TIME RESPONSE OF THE PROLATE SPHEROIDAL IMPEDANCE ANTENNA.

摘要

This dissertation considers two problems dealing with transient radiation from antennas. The first problem deals with the early time response of the spherical antenna while the second examines the late time response of the spheroidal impedance antenna. Two points of view were analyzed. The spherical antenna was considered in the context of the far field while the prolate spheroidal antenna with an impedance boundary condition was considered from the point of view of the input admittance.;The late time response of the prolate spheroidal antenna with an impedance boundary condition is determined by first deriving the steady state solution. A low frequency representation is then obtained and these results are continued to the complex frequency plane. From these results an equivalent circuit is found for the first two modes of the spheroidal antenna as a function of eccentricity. The variation of the pole positions for the two modes is determined as a function of the eccentricity and the reactive coating. The transient response is found and the effect of a dispersive medium is discussed.;The early time response of the spherical antenna is determined by a two step process. First the high frequency representation is derived by use of the Watson transformation. These results are continued to the complex frequency domain and the inverse Laplace transform is performed to obtain the time domain solution. This result is compared to previous analyses and discrepancies are discussed.