AbstractA procedure to include conductor loss in interdigital capacitor based dielectric constant measurements is proposed. The effect of conductor loss and contact resistance can be regarded as a series resistor connected to the interdigital capacitor. If the thickness of the conductor film is known, the conductor loss could be calculated and subtracted from the measurement results. In the frequency range where the dielectric constant of the material in test does not change with frequency, the conductor loss could also be obtained by measuring the frequency dependence of the impedance of the interdigital capacitor. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 566–568, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23141