Bandwidth control in acoustically coupled AlN contour mode MEMS filters

This paper reports a novel method to acoustically couple higher order AlN contour mode resonators and engineer wide bandwidth filters by controlling the number of electrodes, the size of the overhang and the spacing between electrodes. By exciting a higher order resonance mode using multiple metal electrodes on one side of the device and picking up the generated signal on the other, the location of the response poles can be engineered to create a broader band, wider than previously achieved with similar AlN contour-mode devices. CAD-level parameters are experimentally shown to set the location of the poles and therefore the bandwidth.