PERMITTIVITY MEASUREMENTS OF BIOLOGICAL SAMPLES BY AN OPEN-ENDED COAXIAL LINE

Abstract

We previously reported on the complex permittivity and dc conductivity of\nwaste-activated sludge. The measurements, spanning a frequency range of 3 MHz\nto 40 GHz, were made using an open-ended coaxial transmission line. Although\nthis technique is well established in the literature, we found that it was\nnecessary to combine methods from several papers to use the open-ended coaxial\nprobe to reliably characterize biological samples having a high dc\nconductivity. Here, we provide a set of detailed and practical guidelines that\ncan be used to determine the permittivity and conductivity of biological\nsamples over a broad frequency range. Due to the electrode polarization effect,\nlow frequency measurements of conducting samples require corrections to extract\nthe intrinsic electrical properties. We describe one practical correction\nscheme and verify its reliability using a control sample.\n