Accession Number:

AD0432047

Title:

THE DOUBLE-HELIX ANTENNA AND ITS VARIANTS: A NEW CLASS OF TUNABLE ENDFIRE ANTENNAS,

Descriptive Note:

Corporate Author:

AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s):

Report Date:

1963-12-01

Pagination or Media Count:

14.0

Abstract:

Endfire antennas develop their maximum gain when the phase velocity of the surface wave traveling along the structure is adjusted to its optimum value determined as a function of antenna length and operating frequency. These antennas usually have a relatively small pattern bandwidth and, if maximum gain is desired, can be used over only a small frequency range. The antennas described in this paper inaugurate a new class of antennas that are tunable for maximum gain in the endfire direction over a wide frequency range tuning is accomplished by changing the phase velocity continuously or in prescribed steps. Such antennas include certain spatial configurations of the double helix a novel type of endfire antenna and its artificical and natural dielectric variants. Useful structures are obtained through parallel displacement of two juxtaposed elements or angular displacement of a scissors arrangement. Model measurements show that maximum gain can be obtained over a frequency range of more than 21. Tuning effects are illustrated in detail by means of nearfield plots of a tuned dielectric antenna. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE