Accession Number:

AD0423686

Title:

DIELECTRIC CONSTANT AND LOSS MEASUREMENTS ON HIGH-TEMPERATURE MATERIALS

Descriptive Note:

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR INSULATION RESEARCH

Personal Author(s):

Report Date:

1963-10-01

Pagination or Media Count:

90.0

Abstract:

Measurement techniques for the frequency range 100 to about 2.5x10 to the 10th power are discussed for temperatures to 1650 C. These include the use of bridges, resonant circuits, standing-wave methods, and resonant cavities. Data on crystals of Al2O3, Cr2O3, MgO, LaAlO3, Y2O3 on multicrystalline bodies of Al2O3, BeO, MgO, Mg2SiO4, Ta2O5, ThO on glass ceramics, silica glass, and BN are presented over smaller temperature and frequency ranges. Pyrolitic BN has a low loss tangent o.0004 at 1375 C, 4.8x10 to the 9th power cps and a low temperature coefficient of dielectric constant. Some aluminas and silicas exhibit loss tangents of ca. 0.0006 at 1000 C in the microwave region. Microwave losses are due partly to the charge transfer responsible for low-frequency conductivity and to the vibration spectra of infrared absorption. Both losses are increased by the addition of impurities.

Subject Categories:

  • Miscellaneous Materials
  • Crystallography
  • Electricity and Magnetism

Distribution Statement:

APPROVED FOR PUBLIC RELEASE