Accession Number : AD0434099


Title :   DERIVATION OF EROSPACE ANTENNA COUPLING - FACTOR INTERFERENCE PREDICTION TECHNIQUES.


Descriptive Note : Interim technical rept. no. 7, 1 Aug-1 Nov 63,


Corporate Author : MICHIGAN UNIV ANN ARBOR COOLEY ELECTRONICS LAB


Personal Author(s) : Adams,D K ; DeHart,W R ; Kalafus,R M ; Simanyi,A I ; Harris,R B


Report Date : Jan 1964


Pagination or Media Count : 23


Abstract : Three Archimedean spirals were tested for antenna patterns and coupling patterns: (1) circular, (2) square, and (3) dielectric-cavity-backed circular. The latter was used in the fundamental mode, with out-of-phase currents at the feed. The square spiral exhibits a broader beam, a better ellipticity ratio, and a larger VSWR over the band, than of the circular spiral. The effect of the dielectric is to broaden the beam, since the antenna radiates from a smaller region. This broadening effect is significant when the cavity thickness is greater than one-quarter wavelength. Another square spiral, oppositely wound, was tested for coupling patterns, and exhibited essentially mirror-image behavior to the first square spiral. A theoretical consideration of mounted flush-horn antennas indicates rough coupling estimates may be obtained rather simply from curves given. The feed and geometry of the horn determine the aperture field distribution; this, in turn, determines the fields in space and along the ground plane. Phase variations due to horn flare tend to smooth out sidelobes and broaden the beam. Fresnel zone phenomena are not considered. (Author)


Descriptors :   HORN ANTENNAS , SPIRAL ANTENNAS , ANTENNA FEEDS , RADIOFREQUENCY INTERFERENCE , ANTENNA LOBES


Distribution Statement : APPROVED FOR PUBLIC RELEASE