Dielectric Response of Select Ionic Solutions Using a Loaded Microwave Cavity Operating Near 9 GHz, 21 GHz, and 29 GHz as a Probe^*

A loaded resonant microwave cavity operated near 9 GHz, 21 GHz, and 29 GHz was used as a probe to obtain the frequency response of select ionic solutions. Various ionic concentrations of copper sulfate and sodium chloride in water were investigated in order to establish the nature of relaxation mechanisms in each solution over a range of microwave frequencies from 9 GLIz to 30 G Hz and at room temperature. The experimental results obtained on frequency shifts and change of resonance width at half-power maxima were used to deduce a relaxation time for each solution using Slater’s cavity perturbation equations. A correlation between ionic concentration, volume of the sample and frequency of the appliedfieldwithdielectric response was analyzed. The height of the potential barrier was computedfronz experimental data.It was found that the change in width of the resonance profile relative to the shift in resonant frequency is almost constant at 9 .0 GHz but shows some systematic variation from a constant value for higher frequencies. The broad range of frequencies and ionic concentration chosen for this study may lead to a model for electrolytic solution behavior under an impressed external electromagnetic field and specifically to an understanding of the ion barriers to bulk penetration of different ionic concentrations to impressed microwave fields.