Surface acoustic wave resonator, surface acoustic wave device, and communications equipment
First Claim
1. A surface acoustic wave resonator comprising a plurality of IDT electrodes arranged on a piezoelectric substrate along a propagation direction of a surface acoustic wave propagating on the piezoelectric substrate and each having a number of electrode fingers extending in a direction perpendicular to the propagation direction, wherein two adjacent IDT electrodes out of the plurality of IDT electrodes comprises a variable pitch section, that is a section in close proximity to an end of the other IDT electrode, where an electrode finger pitch is variable, and a fixed pitch section, where the electrode finger pitch is fixed, the electrode finger pitch in the variable pitch section basically decreases toward the boundary between the two adjacent IDT electrodes, and the minimum electrode finger pitch portion in the two adjacent variable pitch sections is on one side spaced apart from the boundary.
1 Assignment
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Accused Products
Abstract
A plurality of IDT electrodes 2 to 7 each having a large number of electrode fingers extending in a direction perpendicular to a propagation direction of a surface acoustic wave propagating on a piezoelectric substrate 1 are arranged on the piezoelectric substrate 1 along the propagation direction, and each of the two adjacent IDT electrodes out of the plurality of IDT electrodes 2 to 7 comprises a variable pitch section and a fixed pitch section. The electrode finger pitch in the variable pitch section gradually decreases toward the boundary between the two adjacent IDT electrodes, and the minimum electrode finger pitch portion in the two variable pitch sections is on one side spaced apart from the boundary. There can be provided a surface acoustic wave apparatus having a large pass bandwidth, having a low insertion loss, and having improved flatness in a pass band.
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Citations
12 Claims
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1. A surface acoustic wave resonator comprising a plurality of IDT electrodes arranged on a piezoelectric substrate along a propagation direction of a surface acoustic wave propagating on the piezoelectric substrate and each having a number of electrode fingers extending in a direction perpendicular to the propagation direction, wherein
two adjacent IDT electrodes out of the plurality of IDT electrodes comprises a variable pitch section, that is a section in close proximity to an end of the other IDT electrode, where an electrode finger pitch is variable, and a fixed pitch section, where the electrode finger pitch is fixed, the electrode finger pitch in the variable pitch section basically decreases toward the boundary between the two adjacent IDT electrodes, and the minimum electrode finger pitch portion in the two adjacent variable pitch sections is on one side spaced apart from the boundary.
Specification