The absorption of energy by a wireless aerial
Published online by Cambridge University Press: 24 October 2008
Extract
If a receiving aerial is placed in the field of a wave produced by a distant transmitter, currents are induced in the receiving aerial and these dissipate energy in the ohmic resistances of the aerial. This energy may be thought of as being absorbed directly from the incident wave, but this viewpoint gives no insight into the mechanism by which the absorption takes place. In this paper the following alternative way of regarding the phenomenon is considered. The currents induced in the aerial cause it to re-radiate a secondary wave. The electric and magnetic fields of this secondary wave combine with those of the unabsorbed incident wave to give resultant fields which have, in general, a direction different from those of the incident wave. These resultant fields give rise to energy flows which are different from those in the incident wave, both in magnitude and direction. In this way a flow of energy into the aerial is produced, by the superposition of the incident and the re-radiated fields. It is important to notice that if this viewpoint is adopted we must add the secondary re-radiated wave to the unabsorbed main wave, the addition, in itself, producing the requisite absorption.
- Type
- Research Article
- Information
- Mathematical Proceedings of the Cambridge Philosophical Society , Volume 27 , Issue 4 , October 1931 , pp. 588 - 592
- Copyright
- Copyright © Cambridge Philosophical Society 1931
References
* Barfield, and Munro, , Journ. Instit. Electr. Engs., 67, 253 (1929).Google Scholar
* Martens, , Physikalische Grundlagen der Elektrotechnik, Vol. 2, p. 321 (Vieweg, 1915).Google Scholar
† Bechmann, , Zeit. f. Hochfrequenztechnik, 36, 182 (1930).Google Scholar
‡ For a discussion of these two methods see Pistolkors, , Inst. Radio Engs., 17, 562 (1929).Google Scholar
* Bloch, , Précis d'électricité théorique, p. 271.Google Scholar
- 1
- Cited by