Dielectric dispersion at microwave frequencies in the camphor series

By an adaptation of the Roberts and von Hippie “short circuit-line” method the dielectric constant and loss at 3.20 cm. wavelength of dl-camphor, d-camphor and isoborneol have been measured in the solid state over a wide range of temperatures and in the liquid phase just above the melting point. The values here obtained are compared with the radio-frequency values found in the literature. At 3.20 cm. the rotator phase of all three compounds contains nearly the whole dispersion region. The temperature of maximum loss at this frequency is about 38°C for d-camphor, 28°C for dl-camphor and 72°C for isoborneol.