IIDT type surface acoustic wave device
AssigneeMurata Manufacturing Co., Ltd.
InventorsTakaharu Kawakatsu, Yutaka Tada, Hideharu Ieki
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Abstract
An IIDT type surface acoustic wave filter (41) comprising a piezoelectric substrate and at least three IDTs (44 to 46) which are arranged on a surface of the piezoelectric substrate along the direction of surface wave propagation, the IDT (44) being inverted in phase with respect to the other IDT (46) while these IDTs (44) and (46) are connected in series to each other through the ground potential, thereby balancing inputs or outputs.
Claims12
An IIDT type surface acoustic wave device comprising a piezoelectric substrate and at least three interdigital transducers formed on a surface of said piezoelectric substrate along a direction of surface wave propagation and each provided with a pair of comb electrodes having plural electrode fingers interdigitating with each other, said interdigital transducers each being one of two types, said two types comprising an input and an output interdigital transducer along the direction of surface wave propagation,
- said transducers of the same type comprising an even number and being divided into first and second groups wherein a group may comprise a single transducer, each interdigital transducer in a first group being inverted in phase with respect to each interdigital transducer in a second group, said two groups being formed along a center of a region provided with all said interdigital transducers, said two groups of said transducers being connected in series to each other.
An IIDT type multi-stage surface acoustic wave device comprising a piezoelectric substrate and at least two stages of IIDT type surface acoustic wave devices formed on said piezoelectric substrate and successively connected with each other,
- each said IIDT type surface acoustic wave device comprising at least one of an input stage and an output stage, each said IIDT type surface acoustic wave device comprising a piezoelectric substrate and at least three interdigital transducers formed on a surface of said piezoelectric substrate along a direction of surface wave propagation and each provided with a pair of comb electrodes having plural electrode fingers interdigitating with each other, said interdigital transducers each being one of two types, said two types comprising an input and an output interdigital transducer along the direction of surface wave propagation,
- said transducers of the same type comprising an even number and being divided into first and second groups wherein a group may comprise a single transducer, each interdigital transducer in a first group being inverted in phase with respect to each interdigital transducer in a second group, said two groups being formed along a center of a region provided with all said interdigital transducers, said two groups of said transducers being connected in series to each other.
Dependencies are inferred from the claim text.