Broadband coaxial cavity resonator for complex permittivity measurements of liquids

A novel cavity perturbation technique using coaxial cavity ruonators for the measurement of complex permittivity of liquids is presented. The method employs two types of resonators (Resonator I and Resonator ll). Resonator l operates in the fre­ quency range 600 MHZ-7 CH2 and resonator ll operates in the frequency range 4 Gliz-14 CH2. The introduction of the capillary tube filled wit? the sample liquid lnthe coaxial resonator causes shifts in the resonance frequency ant. loaded Q-factor of the nes­ onator. The shifts in the resonance frequency and loaded Q-factor are used to determine the real and imaginary parts of the complex permittivity of the sample liquid, respectively. Using this technique, the dielectric parameters of water and nitrobenzene are measured. The results are compared with those obtained using other standard methods. The sources of errors are analyzed.