The present invention relates to systems and devices for delivering energy to tissue for a wide variety of applications, including medical procedures (e.g., tissue ablation, resection, cautery, vascular thrombosis, treatment of cardiac arrhythmias and dysrhythmias, electrosurgery, tissue harvest, etc.). In particular, the present invention relates to systems and devices for the delivery of energy with optimized characteristic impedance. In certain embodiments, methods are provided for treating a tissue region (e.g., a tumor) through application of energy with the systems and devices of the present invention.