Device with an electroacoustic balun

A method of operating an electroacoustic balun, the method comprising:

• in an electroacoustic balun having:
• a film of piezoelectric material having a first and a second surface separated by a thickness of the film;
• a first and second pair of electrodes on the first surface, each pair comprising a first electrode and a second electrode defining an interface between the edges of the first electrode and the second electrode in the pair, the first electrode of the first and second pair being electrically connected to each other or shared by the first and second pair, the interfaces of the first and second pair being shaped geometrically identical to each other;
• a common electrode on the second surface, the common electrode having at least partial overlaps with all of the electrodes of the first and second pair;
• and
• piezoelectrically polarized regions in said film at least in part of each of the overlaps, with piezoelectric polarization components perpendicular to the first surface, the direction of the polarization components of the regions in the overlaps with the first electrode and the second electrode in the first pair being equal to each other, the directions of the polarization components in the overlaps with the first electrode and the second electrode in the second pair being mutually opposite:
• applying an electrical signal between one of the common electrode and the first electrodes and the common electrode and the second electrodes.