Accession Number:

ADA076769

Title:

Millimeter Wave Hardened Antenna Window Materials Development.

Descriptive Note:

Final rept. Jul 78-Apr 79,

Corporate Author:

GENERAL ELECTRIC CO PHILADELPHIA PA RE-ENTRY AND ENVIRONMENTAL SYSTEMS DIV

Report Date:

1979-08-01

Pagination or Media Count:

283.0

Abstract:

A materials development and characterization program has been conducted with the goal of developing hardened antenna window materials for application to millimeter wave and infrared sensors for ballistic missile defense interceptor BMDI applications. Three distinct classes of materials were studied. The ADL-4D6 multidirectionally reinforced silica-silica composite developed in previous BMD work was tested for particle erosion resistance and dielectric properties in the mm wavelength region. A comprehensive study was also performed on the effects of constituent properties and weaving and composite densification variations on the mechanical properties of this material. A second class of refractory dielectrics, ultrahigh purity nitrides of silicon and aluminum, were also examined for their ultimate potential in the BMDI environment. Specimens were prepared by chemical vapor deposition and hot pressing of powders. These were variously tested for mechanical and thermal properties, chemical purity and dielectric properties in X and millimeter wavelength bands. The CVD Si3N4 material in particular showed a decade lower loss tangent than previously reported versions of this ceramic. A third material, Raytran zinc selenide, an infrared window material candidate, was characterized for its thermophysical and mechanical properties from -150 C to 1000 C. Author

Subject Categories:

  • Ceramics, Refractories and Glass
  • Infrared Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE