Dielectric-Guide Antennas for Aircraft
Abstract
An investigation was made of dielectric guide antennas suitable for airborne radar applications. The study was directed toward streamlined and recessed types having compact design, minimum weight, and low minor lobe radiation. Of the many forms investigated, the tapered polystyrene rod (polyrod) is the most practicable. Highly directive polyrods weigh 6 ounces and are 9 inches long at 10,000 Mc, but lengthen in direct proportion to wavelength. Sidelobe reduction to at least 17 db is possible by properly dimensioning the rod; minimum practical beamwidth for a single rod is 21, and maximum gain is 18 db, obtained with a polyrod 7.5 wavelengths long. These characteristics are not mutually obtainable, but excellent compromises can be made. Arrays may be used to obtain narrower beamwidths and higher gains. Several methods have been found of strengthening the polyrod, which should allow its use in wind streams of order 580 knots at 20,000 feet altitude. Radiation measurements made on a specially designed series of polyrods are included to facilitate the design and development of end-firerods and broadside arrays for particular applications. Radiation effects of mounting the polyrod near aircraft fuselages were also recorded.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 19, 1951
- Accession Number
- AD1216357
Entities
People
- D. H. Russell
- F. E. Boyd
Organizations
- United States Naval Research Laboratory