Accession Number : AD0600535

Title :   RECEPTION AND TRANSMISSION OF TRANSIENT ELECTROMAGNETIC FIELDS.

Descriptive Note : Technical rept.,

Corporate Author : HARVARD UNIV CAMBRIDGE MASS CRUFT LAB

Personal Author(s) : Schmitt,Hans J.

Report Date : 13 JAN 1964

Pagination or Media Count : 38

Abstract : The receiving and transmitting properties of small linear antennas, conical antennas, and loops for transient electromagnetic fields were investigated experimentally. Short electrical dipoles loaded by a capacitance represented by a cathode follower can be used successfully for the measurement of transient fields with rise times of less than 1 nanosecond, if the first antenna resonance is suppressed by a series resistor at the base of the antenna. The currents induced on nonresonant structures by transient electromagnetic fields are investigated and their application to a direct measurement of the time sequence of the electromagnetic field is discussed. Signals with a simple and known time dependence such as a unidirectional pulse can be radiated into space if the reflection of current waves at discontinuities of the antenna structure is avoided. In a manner similar to that useful for the absorption of continuous waves in media with a stratified conductivity, it is shown that reflections at discontinuities can be avoided by dipoles with tapered resistive loading. (Author)

Descriptors :   (*LOOP ANTENNAS, WAVE PROPAGATION), (*CONICAL ANTENNAS, WAVE PROPAGATION), (*ELECTROMAGNETIC FIELDS, ANTENNAS), TRANSMISSION LINES, TRANSIENTS

Distribution Statement : APPROVED FOR PUBLIC RELEASE