Hostname: page-component-cd9895bd7-gxg78 Total loading time: 0 Render date: 2024-12-25T01:58:04.972Z Has data issue: false hasContentIssue false

A reciprocity theorem on the propagation of radio waves via the ionosphere

Published online by Cambridge University Press:  24 October 2008

K. G. Budden
Affiliation:
Cavendish LaboratoryCambridge

Abstract

The reciprocity theorem for electrical systems which include a radiation link was believed to be true only when the media within the system have dielectric constants which are symmetric tensors. This condition is not fulfilled by the ionosphere, so that the reciprocity theorem is not generally applicable when the radiation link includes one or more reflexions from the ionosphere. It is here proved that, when the ionosphere is horizontally stratified, and when the path from transmitter to receiver is in the magnetic meridian (north-south and south-north transmission), the reciprocity theorem applies (a) when the transmitting and receiving aerials both radiate or receive waves whose electric vector is in the plane of incidence, and (b) when both aerials radiate or receive waves whose electric vector is horizontal. Further, (c) if the electric vector radiated or received is horizontal for one aerial and in the plane of incidence for the other, then there is reciprocity in signal amplitude, but the phase changes for transmission in the two directions differ by 180°. These results are valid for any law of variation of electron density and collision frequency with height. They are based on a ‘full-wave’ theory, and therefore apply to all frequencies. They are unaffected if the path includes multiple reflexions, and if allowance is made for the curvature of the earth.

Type
Research Article
Copyright
Copyright © Cambridge Philosophical Society 1954

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

(1)Appleton, E. V.J. Instn elect. Engrs, 71 (1932), 642.Google Scholar
(2)Banerjea, B. K.Proc. roy. Soc. A, 190 (1947), 67.Google Scholar
(3)Booker, H. G. and Walkinshaw, W.Physical Society Report on meteorological factors in radio-wave propagation (London, 1946).Google Scholar
(4)Carson, J. R.Proc. Inst. Radio Engrs, N. Y., 17 (1929), 952.Google Scholar
(5)Clemmow, P. C. and Heading, J.Proc. Camb. phil. Soc. 50 (1954), 319.CrossRefGoogle Scholar
(6)Dällenbach, W.Arch. Elektrotech. 36 (1942), 153.CrossRefGoogle Scholar
(7)Goubau, G.Hochfrequenztech. u. Elektroakust. 60 (1942), 155.Google Scholar
(8)Sommerfeld, A. and Pfrang, H.Jb. drahtl. Telegr. 26 (1925), 93.Google Scholar