A coagulation system is provided for use in biological tissue. The coagulation system includes a handle, a radiofrequency (RF) generator, and an electrode array. The electrode array includes two or more pair of bipolar electrodes slideably coupled in channels of the handle. The bipolar electrodes electrically couple to the RF generator, and the electrode array is configured to deliver a balanced energy density in a target volume of the biological tissue. The balanced energy density delivered by the electrode array results in thermal coagulation necrosis of a rectangular volume of biological tissue.