Accession Number : ADP007449

Title :   Spiral Antennas Over Closely Spaced Ground,

Corporate Author : ILLINOIS UNIV AT URBANA ELECTROMAGNETICS LAB

Personal Author(s) : Smith, D. W. ; Mayes, P. E.

Report Date : FEB 1992

Pagination or Media Count : 29

Abstract : This paper describes recent progress in the development of low-profile radiating-line antennas for producing circularly polarized (CP) radiation. Numerical studies of annular sector and log-spiral radiating lines have been done using a numerical electromagnetics code based upon patch basis functions. The relative merits and performance limitations of annular sector (ANSERLIN), one-arm spirals, and two-arm spirals are discussed. The results of the computer simulations were used to choose parameters for some physical models. Measured performance is close to that predicted by computer. A limiting factor in achieving large bandwidths has been traced to the rather slow rate of attenuation of the current along the antenna arm. Much greater bandwidth has been obtained by placing an absorbing film between the radiating arm and the ground plane.

Descriptors :   *ANTENNAS, ATTENUATION, BANDWIDTH, COMPUTERS, FILMS, FUNCTIONS, LIMITATIONS, MODELS, PARAMETERS, PROFILES, RADIATION, RATES, SIMULATION.

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE