Accession Number : AD0910331

Title :   A Study of the Application of the Extended Aperture Principle to Very Broad Band Steerable HF Arrays.

Descriptive Note : Final rept. 12 Jun 70-18 Jun 71,

Corporate Author : TECHNOLOGY FOR COMMUNICATIONS INTERNATIONAL MOUNTAIN VIEW CA

Personal Author(s) : Tanner, R. L.

Report Date : APR 1973

Pagination or Media Count : 163

Abstract : The purpose of this program was to investigate the applicability of the Extended Aperture technique to the design and construction of large, linear, broadband, very high gain, high-power steerable arrays. Previous studies had encountered difficulty in construction of vertically polarized arrays operating over a bandwidth of greater than 3:1, and have had essentially no success with horizontally polarized arrays. The major problems to be addressed were quite clear. In the case of vertical arrays using log-periodic elements, the following problem areas dominate: (1) Maintaining proper radiation when the element spacing is such that strong negative mutuals are encountered; (2) Related to (1), the suppression of a tendency to develop two active regions at certain frequencies; (3) Proper low-frequency truncation in a very dense array. In the case of horizontal arrays using log-periodic elements, the following interrelated problems are of major concern: (1) Separation of phase centers resulting in grating lobes; and (2) Low frequency truncation.

Descriptors :   (*LOG PERIODIC ANTENNAS, STEERING), (*ANTENNA APERTURES, LOG PERIODIC ANTENNAS), BROADBAND, PHASED ARRAYS, POWER, GAIN, HIGH FREQUENCY, COMPUTER PROGRAMS, AZIMUTH, ELECTRICAL IMPEDANCE, COUPLING CIRCUITS, ANTENNA COMPONENTS, ANTENNA FEEDS, EFFICIENCY, ANTENNA LOBES, ANTENNA RADIATION PATTERNS.

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE