Abstract :
For most glasses at room temperature there is a broad minimum of dielectric loss covering the radio-frequency region; this lies between the vibration-loss region, occurring at 10 Gc/s and above, and the migration-loss region at audio and sub-audio frequencies. The vibration losses are nearly independent of temperature, whereas the migration losses move rapidly to higher frequencies at higher temperatures. Recent work on the migration losses is reviewed and some new results are presented which show that many glasses give nearly the same reduced loss curve of ¿¿/¿¿ against log (fp) although the values of ¿¿ and of p at a given temperature may be quite different. Some differences are noted between single-alkali and mixed-alkali glasses. The use of the reduced loss curve is demonstrated by a calculation for a number of Corning glasses of the variation of tan ÿ with temperature at 1 Mc/s, using only resistivity data and the roomtemperature permittivity.
