Ceramic insulations for high-frequency work

During the past few years, ceramic materials with properties especially suited to working at radio frequencies have been developed. The present paper contains a brief account of the manufacture of such materials, followed by a discussion of their mechanical and electrical properties. It is pointed out that many of the discrepancies in previously published data may be explained by the difficulties of the measurements and by the variation of some of the quantities to be measured with factors not always sufficiently controlled or specified. The differences in values obtained on test samples and those which may be realized practically are emphasized. The paper concludes with a brief account of the application of ceramic materials in the radio industry.