An oblong electrochemical double-layer capacitor is disclosed having a modified jelly roll design and having a plurality of fingers extending from each electrode in substantially the same direction. The waveplate is offset from the center or midpoint of the waveguides such that the intersections of the waveplate with the waveguides result in little or no back-reflection, while also providing polarization independent operation. At least a separator is disposed in the lower base parallel to the lateral walls.