Boundary acoustic wave device

A boundary acoustic wave device, comprising:

• a piezoelectric substrate;
• a first dielectric layer provided on the piezoelectric substrate;
• and
• an electrode structure provided at an interface between the piezoelectric substrate and the first dielectric layer;
• wherein
• the electrode structure includes:
• a plurality of series arm resonators connected to one another in series on a series arm that connects an input terminal and an output terminal;
• a parallel arm resonator connected between the series arm and a ground potential on each of a plurality of parallel arms provided between the series arm and the ground potential;
• a plurality of ground wiring lines respectively connected to ends of the plurality of the parallel arms to be connected to the ground potential;
• and
• a plurality of ground pads respectively connected to the plurality of the ground wiring lines;
• wherein
• the electrode structure defines a ladder filter;
• the boundary acoustic wave device further comprises:
• a signal wiring line defining the series arm arranged so as to be located between at least two of the plurality of the ground pads;
• and
• a ground connection conductor arranged to electrically connect the at least two of the plurality of ground pads;
• the signal wiring line is arranged to three-dimensionally cross the ground connection conductor with the first dielectric layer therebetween;
• and
• all of the plurality of ground pads are electrically connected to one another.