A method of manipulating ions comprises injecting ions between a first surface and a second surface positioned parallel to and spaced apart from each other and defining a central axis therebetween, wherein the first surface comprises first outer electrodes coupled to the first surface and a first inner array of electrodes coupled to the first surface and positioned between the first outer electrodes, wherein the second surface comprises second outer electrodes coupled to the second surface and a second inner array of electrodes coupled to the second surface and positioned between the second outer electrodes, and applying a frequency modulated RF voltage to at least one electrode of the first inner array of electrodes or the second inner array of electrodes to confine ions between the first surface and the second surface and to guide ions between the first surface and the second surface along the central axis.