HIGH-TEMPERATURE ANTENNA INVESTIGATION.
Abstract
Experimental effort was continued on high-temperature models of waveguide slot, annular slot, and printed spiral antennas. Two separate alumina windows sealed across the open end of a columbium S-band waveguide have developed cracks after cooling. It appears that the nominally matched thermal coefficients of expansion of these materials are not exact enough to prevent fracture of thin alumina windows. An annular slot antenna assembly employing a corrugated metal disk/alumina window has been electrically matched. This assembly will provide information on the suitability of deformable assemblies to accommodate unmatched thermal expansion coefficients of materials. Fused silica and alumina substrates and fired-on platinum conductors have been used in hightemperature spiral antenna assemblies. The low loss of these substrates produces rapidly fluctuating VSWR values (with frequency), and the high dielectric constant of the alumina causes an apparent narrowing of antenna bandwidth. Power-handling tests of thoriated nickel obstacles in a waveguide showed no unusual performance as a function of temperature. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1964
- Accession Number
- AD0607615
Entities
People
- G. F. Buranich
Organizations
- Calspan