Scientists from NPL have developed improvements to a technique for measuring dielectric permittivity and loss of materials at MHz frequencies. The method used is named after two NPL scientists who developed in the 1930, Hartshorn and Ward. The findings are presented in the team's paper, "Low loss dielectric measurements in the frequency range 1—70MHz by using a Vector Network Analyser," recently published in Measurement Science and Technology. This method allows the permittivity and loss of a sheet of dielectric material placed between the plates of a capacitor to be determined by resonating it with a coil inductor. The value of the technique is that very low losses can be determined from measurement of small changes in Q-factor.