Radiation characteristics of traveling-wave antennas excited by nonsinusoidal currents

Traveling-wave antennas excited by nonsinusoidal currents for high-resolution exploration are proposed. To begin, the analytic expressions of the radiation waveforms in the far zone produced by a single transient of current traveling along a straight wire are derived in a time domain. The radiation characteristics of traveling-wave antennas excited by nonsinusoidal current, such as the mean-power pattern functions and the directivity, are then given, and the space waveform control and radiation efficiency are discussed. On the basis of earlier results, the radiation waveforms of dipole antennas excited by pulse current are obtained from a time-domain analysis. These waveforms are compared with corresponding waveforms obtained from frequency-domain analysis and data presented by Schmitt et al. (1966) and Palciauskas and Beam (1970); good agreement is obtained in various radiation directions.