a dielectric filter utilizing a plurality of serially coupled resonators having attenuation maximums at the lower side or higher side , or both , of a pass band frequency region . the filter may include an input element which is coupled with both of a first resonator and a second resonator , and may also include an output element which is coupled with both the last and the next - to - last resonator . in the dielectric filter , it is not necessary to provide an external wire connection to generate such attenuation maximums .