Precise measurement of the dielectric constant of seawater at 1.413 GHz: The capillary exit hole correction

The effect of the capillary-tube exit holes in the microwave resonant cavity used to measure the dielectric constant of seawater at L-band, is investigated. The cavity technique is a perturbation method that uses the change in the resonant frequency and Q of the cavity when seawater is added to determine the complex dielectric constant of seawater. The tube, through which the seawater is introduced into the cavity, enters through two small center holes in the cavity's endplates. It has been suggested in the literature that these small exit holes could affect the change in the resonant frequency measurement, thus introducing a frequency pulling error into the measurements.