a tunable capacitor includes a first electrode and a second electrode , each being formed of a conductive material . the tunable capacitor further includes a third electrode between the first electrode and the second electrode , and a dielectric material interposed between the first electrode and the third electrode , and between the second electrode and the third electrode . the third electrode is movable relative to the first electrode and the second electrode by a stepper motor , to adjust and tune a capacitance of the tunable capacitor .