The Keysight 16451B is used to evaluate the dielectric constant of solid dielectric materials accurately and complies with ASTM D150. The Keysight 16451B employs the parallel plate method, which sandwiches the material between two electrodes to form a capacitor. LCR meter or an Impedance Analyzer is then used to measure the capacitance created from the fixture.

The Keysight 16451B dielectric material test fixture provides precise measurements up to 30 MHz when combined with the Keysight E4990A impedance analyzer. The Keysight 16451B, compliant to the ASTM D150 standard, has three electrodes, two of which form a capacitor and the remaining one provides a guard electrode. A part of the electrical field between the two electrodes flows outside of the dielectric material, which causes slightly large capacitance, i.e. “fringe capacitance.” The guard electrode properly absorbs the current flowing through the fringe capacitance and provides accurate measurements.