TACAN ANTENNA TECHNIQUES.
Abstract
The TACAN ground beacon is required to produce a certain modulation in space in all azimuth directions. Essentially, this is a shaped beam in the horizontal plane which rotates in the same plane. An electronically scanned antenna is described which is capable of producing this modulation in space. This antenna consists of a ring array of 36 radiators, a power distribution network, and only two variable phase shifters. The power distribution network consists of a 36- by 36-port Butler matrix. While all 36 output ports are used, only three of the input ports are utilized. Transmitting power is divided unequally three ways for feeding into the three inputs. A variable phase shifter is inserted into two of the three input ports. When the phase shifters are activated, the desired modulation is produced at all 36 outputs. All of the input power is radiated except for normal transmission line losses. The chief virtue of this technique is that only two variable phase shifters are required to scan the ring array. Each phase shifter is required to handle only three to four percent of the input power. The drive and control circuitry is comparatively simple since only two active elements are required. A feasibility model was fabricated and tested. Test results are given as well as theoretical pattern computations. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1967
- Accession Number
- AD0824250
Entities
Organizations
- RTX