Investigation of radiation characteristics of Hertz dipole excited by superwide signal

Abstract

Methods of antenna characteristic's retrieval by the near-zone field measurements are widely used now. Along with this, interest to non-harmonic or transient signals is growing up. This is connected with widening their applications.

That is why it is interesting to investigate radiation field characteristics at a short distance from antenna in detail. As a sample antenna we take a Hertz dipole excited by a finite pulse.

A problem of the radiation of a short-length vibrator with arbitrary time- dependence of the induced current density is considered. To solve this problem, three-dimensional tensor Green’s function of the wave equation was applied. General expressions for the electric and magnetic components of the electromagnetic field of a Hertz dipole were obtained. These expressions enable one to investigate both stationary and transient sources. For example, the expression for the electric component of the radiated field is like follows:

*

where *.

Finite-length vibrator antenna characteristics were studied in more detail when we took a current of the re-entering discharge as an exciting current pulse.

Dependencies of the pulse shape, duration and amplitude on the distance from antenna were investigated by means of computer analysis of obtained formulas.