ASTM D2520 – Standard Test Methods for Complex Permittivity (Dielectric Constant) of Solid Electrical Insulating Materials at Microwave Frequencies and Temperatures to 1650 °C
Description:
Significance and Use
4.1 Design calculations for such components as transmission lines, antennas, radomes, resonators, phase shifters, etc., require knowledge of values of complex permittivity at operating frequencies. The related microwave measurements substitute distributed field techniques for low-frequency lumped-circuit impedance techniques.
4.2 Further information on the significance of permittivity is contained in Test Methods D150.
4.3 These test methods are useful for specification acceptance, service evaluation, manufacturing control, and research and development of ceramics, glasses, and organic dielectric materials.
Scope
1.1 These test methods cover the determination of relative (Note 1) complex permittivity (dielectric constant and dissipation factor) of nonmagnetic solid dielectric materials.
Note 1: The word “relative” is often omitted.
1.1.1 Test Method A is for specimens precisely formed to the inside dimension of a waveguide.
1.1.2 Test Method B is for specimens of specified geometry that occupy a very small portion of the space inside a resonant cavity.
1.1.3 Test Method C uses a resonant cavity with fewer restrictions on specimen size, geometry, and placement than Test Methods A and B.
1.2 Although these test methods are used over the microwave frequency spectrum from around 0.5 to 50.0 GHz, each octave increase usually requires a different generator and a smaller test waveguide or resonant cavity.
1.3 Tests at elevated temperatures are made using special high-temperature waveguide and resonant cavities.
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are inch-pound units that are provided for information only and are not considered standard.
ASTM D2515