| Impulse Radiating Antennas (IRAs) are designed to radiate very fast pulses in a narrow beam with low dispersion and high field amplitude. For this reason they have been used in a variety of applications.;IRAs have been developed for the transient far-field region using paraboloidal reflectors. However, in this dissertation we focus on the near field region and develop the field waveform at the second focus of a prolate-spheroidal IRA. Recent research has shown that it is possible to kill certain skin cancers by the application of fast, high-amplitude electric-field pulses. This has been accomplished by the insertion of electrodes near the tumor, with direct contact from a high-voltage pulse generator. It has been suggested that it would be desirable to be able to apply fast, high-electric-field pulses without direct contact for this biological application, i.e., to irradiate them using an antenna from a distance.;Analytical, numerical and experimental behaviors for the focal waveforms of two and four-feed arm prolate-spheroidal IRAs are explored. With appropriate choice of the driving waveform we maximize the impulse field at the second focus. The focal waveform of a prolate-spheroidal IRA has been explained theoretically, verified experimentally and simulated using the CST-MWS (Microwave Studio) software. Finally, different lens design procedures are discussed for a prolate-spheroidal IRA for better concentrating the energy from an impulse. |
