High Q electroacoustic resonator

An electroacoustic resonator comprising:

• an electrode finger comprising a first end coupled to a busbar, the electrode finger further comprising a first section, a piston section, and a tip section;
• and
• a stub electrode finger extending towards the tip section, wherein the stub electrode finger comprises a stub tip having a rectangular shape;
• wherein the first section extends from the first end to a first piston section interface;
• wherein the piston section extends from the first piston section interface to a second piston section interface, wherein the piston section corresponds to a trap region;
• and
• wherein the tip section extends from the second piston section interface into a portion of a gap region in a direction perpendicular to the busbar, wherein a width of the tip section at a widest position of the tip section is narrower than a width of the first section at a narrowest position of the first section.