Accession Number : AD0912856
Title : Beam Forming Antenna Configurations for Use within a Screen-Type CDAA.
Descriptive Note : Technical rept. no. 44,
Corporate Author : ILLINOIS UNIV AT URBANA RADIO RESEARCH LAB
Personal Author(s) : Bailey, Albert D. ; Walker, Joseph D.
Report Date : JUL 1973
Pagination or Media Count : 64
Abstract : Circularly disposed antenna arrays (CDAA) are used to form highly directional beams for HF transmission, reception and radio direction finding purposes. Concurrent with these applications may be the need to survey preassigned wide angular sectors to the exclusion of other preassigned sectors (selective notching). Circularly disposed antenna arrays of the Wullenweber type have large, vertical, circular, backup screens for omnidirectional working without ambiguity. The interior of this screen has cylindrical reflector properties whrerin paraxial rays along any line of arrival come to focus in a region located approximately D/4 inside the array, where D is the diameter. Because of this fact it should be possible to obtain controlled sector beam forming using combinations of single vertical monopole antennas to achieve inherent directivity with gain. However, because wave interference is a limiting factor its constructive and destructive effects must be taken into account. A study of these possibilities, capabilities and limitations is considered in this report. (Author)
Descriptors : (*ANTENNA ARRAYS, RADIO COMPASSES), (*DIRECTION FINDING, RADIO EQUIPMENT), ANTENNAS, RADIO RECEPTION, RADIO TRANSMISSION, RADIO STATIONS, CYLINDRICAL BODIES, REFLECTORS, ELECTROMAGNETIC SHIELDING, FOCUSING, HIGH FREQUENCY, ANGLE OF ARRIVAL, ANTENNA FEEDS.
Subject Categories : Electrical and Electronic Equipment
Distribution Statement : APPROVED FOR PUBLIC RELEASE