A tissue ablation probe is provided. The probe comprises a proximal electrode element, which includes a proximal electrode stem and a deployable proximal electrode array, and a distal electrode element, which includes a distal electrode stem and a deployable distal electrode array. The probe is configured, such that a majority of electrical energy conveyed between the proximal and distal electrode elements is conveyed between distal termini of the electrode arrays, whereas a relatively small amount of the electrical energy is conveyed between the electrode stems. One or more of the electrodes on the arrays may be optionally insulated to further enhance the electrical characteristics of the arrays.