Three-dimensional finite-element simulations were performed to identify the characteristic frequency associated with the influence of electrode geometry on the impedance response. An expression for the characteristic dimension of the rectangular electrode was found that can be used to estimate the frequency associated with geometry-induced frequency dispersion. These results may serve to guide the design of rectangular-shaped sensors that employ impedance measurements. A systematic approach is presented for selection of appropriate domain size and element density for the finite-element simulations and for estimation of the error in the calculated ohmic resistance. (C) 2018 Elsevier Ltd. All rights reserved.