Accession Number : AD0830023

Title :   COMPATIBILITY STUDIES. VOLUME VII. APPENDIX 6. HARMONIC ANALYSIS OF AN ARRAY COMPRISED OF TWO COUPLED DIRECTIVE ANTENNAS.

Descriptive Note : Final rept. Apr 64-Oct 67,

Corporate Author : MOORE SCHOOL OF ELECTRICAL ENGINEERING PHILADELPHIA PA

Personal Author(s) : Goldhirsh, Julius

Report Date : FEB 1968

Pagination or Media Count : 39

Abstract : An harmonic analysis is performed and the radiation patterns are deduced for an antenna system comprised of two parallel half wave dipoles with parasitic directors above a reflecting plane where the mutual interactions of all the elements are considered. The results illustrate the importance of the radiated interference at the harmonic frequencies that may be introduced when sufficient harmonic power is available at the antenna input. As a criterion to determine the 'worst case' situation, the antenna is assumed matched and fed with equal power at each of the harmonics. The resultant field patterns show: (1) The presence of the director introduces side lobes at the fundamental frequency in both the meridional and azimuthal planes. These lobes peak at levels of 9 and 14 dB down, respectively, when compared to the density in the forward direction. (2) The presence of the directors play less of a role the higher the harmonic. At the seventh harmonic a maximum 1.5 dB difference in value exists when compared to the same antenna configuration when the directors are absent. (3) In the meridional plane at the higher harmonics, side lobe densities exist (e.g., at the 5th and 7th harmonic) which are as intense as the power density in the forward direction for the fundamental frequency. (4) In the azimuthal plane the intensities of the side lobes approach but do not exceed the forward lobe intensity at the same harmonic. The forward lobe density monotonically reduces, the higher the harmonic. (Author)

Descriptors :   (*ANTENNA ARRAYS, HARMONIC ANALYSIS), ANTENNA RADIATION PATTERNS, ELECTRICAL IMPEDANCE, POWER SPECTRA, GAIN, OPTIMIZATION, COUPLING CIRCUITS, ELECTROMAGNETIC COMPATIBILITY.

Subject Categories : Electrical and Electronic Equipment
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE