Study of Antenna Pattern Coverage for a UHF Antenna System on an Aircraft
Abstract
An idealized study of theoretical patterns of a four-element crossed- slot array on a cylinder approximating the fuselage of a KC-135 aircraft has been carried out. The objective is to obtain complete hemispherical coverage with at least 6 dB gain for circular polarization over the band from 250 to 400 MHz. The study shows that 15 beam positions, requiring switching each antenna between 0 degrees and three values of phase shift, will give nearly the desired coverage. Coverage is limited over a small portion of the region, primarily in the fore-aft directions, because of the drop in gain of the individual array elements in these directions. An optimum location for the array on the side of the fuselage is chosen at an angle of 60 degrees from the zenith. (A similar array is required on the opposite side of the aircraft to give coverage on the other side). The effects of multipath reflections are calculated and found to be negligible because of the circular polarization discrimination of the antenna.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 13, 1971
- Accession Number
- AD0732914
Entities
People
- Alan J Simmons
Organizations
- Massachusetts Institute of Technology