Elliptical structure for bulk acoustic wave resonator

An RF filter circuit device, the device comprising:

• a substrate member;
• a dielectric passivation layer overlying the substrate member;
• eleven elliptical-shaped resonator devices overlying the substrate member and configured underlying the dielectric passivation layer, each of the elliptical shaped resonators comprising
• a bottom metal plate;
• a piezoelectric layer overlying the bottom metal plate;
• and
• a top metal plate overlying the piezoelectric layer;
• wherein the top metal plate, the piezoelectric layer, and the bottom metal plate are characterized by an elliptical shape having a horizontal diameter (dx) and a vertical diameter (dy), which can be represented as ellipse ratio R=dx/dy;
• and
• wherein seven of the elliptical-shaped resonator devices are configured in a series configuration;
• and wherein four of the elliptical-shaped resonator devices are configured between a junction of the series configuration and ground, the junctions being before the series configuration, after the second resonator in the series configuration, after the fourth resonator in the series configuration, and after the sixth resonator in the series configuration.