Capacitive element and elastic wave device

An acoustic wave device comprising:

• an IDT electrode including a plurality of repeatedly arranged excitation electrode fingers electrically located on a piezoelectric substrate, wherein a thickness of the piezoelectric substrate is less than twice a repetitive arrangement period of the repeatedly arranged excitation electrode fingers;
• and
• a capacitive element, the capacitive element comprising:
• the piezoelectric substrate;
• a first electrode finger located on the piezoelectric substrate and extending towards a positive side in a first direction;
• and
• a second electrode finger located on the piezoelectric substrate, disposed facing and spaced apart from the first electrode finger in a second direction intersecting the first direction, extending towards a negative side in the first direction, and connected to a different potential from the first electrode finger,
• wherein the first electrode finger includes a first portion extending in the first direction and a second portion extending in the first direction from the first portion, through a first step portion, and at a different position in the second direction from the first portion, and
• wherein the second electrode finger includes a third portion disposed facing the second portion and extending in the first direction, and a fourth portion extending from the third portion, through a second step portion, disposed on a virtual line extending from the second portion in the first direction, and facing the first portion.

A capacitive element comprising:

• a piezoelectric substrate;
• a first electrode finger located on the piezoelectric substrate and extending towards a positive side in a first direction;
• and
• a second electrode finger located on the piezoelectric substrate, disposed facing and spaced apart from the first electrode finger in a second direction intersecting the first direction, extending towards a negative side in the first direction, and connected to a different potential from the first electrode finger,
• wherein:
• the first electrode finger includes a first portion extending in the first direction and a second portion extending in the first direction from the first portion, through a first step portion, and at a different position in the second direction from the first portion,
• the second electrode finger includes a third portion disposed facing the second portion and extending in the first direction, and a fourth portion extending from the third portion, through a second step portion, disposed on a virtual line extending from the second portion in the first direction, and facing the first portion, and
• the first electrode finger includes only the first step portion as a step portion.

A capacitive element comprising:

• a piezoelectric substrate;
• a first electrode finger located on the piezoelectric substrate and extending towards a positive side in a first direction;
• and
• a second electrode finger located on the piezoelectric substrate, disposed facing and spaced apart from the first electrode finger in a second direction intersecting the first direction, extending towards a negative side in the first direction, and connected to a different potential from the first electrode finger,
• wherein:
• the first electrode finger includes a first portion extending in the first direction and a second portion extending in the first direction from the first portion, through a first step portion, and at a different position in the second direction from the first portion,
• the second electrode finger includes a third portion disposed facing the second portion and extending in the first direction, and a fourth portion extending from the third portion, through a second step portion, disposed on a virtual line extending from the second portion in the first direction, and facing the first portion, and
• the first electrode finger includes a protrusion extending from a connection between the second portion and the first step portion towards the fourth portion on the virtual line.

A capacitive element comprising:

• a piezoelectric substrate;
• at least one insertion electrode finger extending in a first direction on the piezoelectric substrate,
• a first electrode finger located on the piezoelectric substrate and extending towards a positive side in the first direction;
• and
• a second electrode finger located on the piezoelectric substrate, disposed facing and spaced apart from the first electrode finger in a second direction intersecting the first direction, extending towards a negative side in the first direction, and connected to a different potential from the first electrode finger,
• wherein:
• the first electrode finger includes a first portion extending in the first direction and a second portion extending in the first direction from the first portion, through a first step portion, and at a different position in the second direction from the first portion,
• the second electrode finger includes a third portion disposed facing the second portion and extending in the first direction, and a fourth portion extending from the third portion, through a second step portion, disposed on a virtual line extending from the second portion in the first direction, and facing the first portion, and
• the at least one insertion electrode finger includes at least one of
• an insertion electrode finger connected to an identical potential to the first electrode fingers and located on a virtual extension line extending, towards the negative side, from the second portion of the first electrode finger including the first step portion located furthest towards the negative side out of a plurality of first step portions, or
• an insertion electrode finger connected to an identical potential to the second electrode fingers and located on a virtual extension line extending, towards the positive side, from the fourth portion of the second electrode finger including the second step portion located furthest towards the positive side out of a plurality of second step portions.

A capacitive element comprising:

• a piezoelectric substrate;
• at least one insertion electrode finger extending in a first direction on the piezoelectric substrate,
• a first electrode finger located on the piezoelectric substrate and extending towards a positive side in the first direction;
• and
• a second electrode finger located on the piezoelectric substrate, disposed facing and spaced apart from the first electrode finger in a second direction intersecting the first direction, extending towards a negative side in the first direction, and connected to a different potential from the first electrode finger,
• wherein:
• the first electrode finger includes a first portion extending in the first direction and a second portion extending in the first direction from the first portion, through a first step portion, and at a different position in the second direction from the first portion,
• the second electrode finger includes a third portion disposed facing the second portion and extending in the first direction, and a fourth portion extending from the third portion, through a second step portion, disposed on a virtual line extending from the second portion in the first direction, and facing the first portion, and
• the at least one insertion electrode finger includes at least one of
• an insertion electrode finger connected to a different potential from the first electrode fingers and located, along an entire length thereof, on a virtual extension line extending, towards the positive side, from the first portion of the first electrode finger including the first step portion located furthest toward the positive side, or
• an insertion electrode finger connected to a different potential from the second electrode fingers and located, along an entire length thereof, on a virtual extension line extending, towards the negative side, from the third portion of the second electrode finger including the second step portion located furthest towards the negative side.