Back to results
US RE37,102 E1Granted
Saw filter with specified electrode dimensions
AssigneeMurata Manufacturing Co., Ltd.
InventorYutaka Tada
Life of this patent
Estimating the term…
Abstract
A surface acoustic wave filter has pairs of interdigital transducers and reflectors formed on a 36° Y-X LiTaO3 substrate, the reflectors sandwiching the interdigital transducers in between. The film thickness h of the electrode fingers of the interdigital transducers and the reflectors is such that 0.06≦h/λ≦0.01 0.10 where λ is the wavelength of the surface acoustic wave adapted to be generated by the filter. The width-to-pitch ratio M/P of these electrode fingers for the interdigital transducers and the reflectors is such that M/P≧0.6 in order to improve the shape factor of the filter.
Claims20
A surface acoustic wave filter comprising:
- a 36° Y-X LiTaO3 substrate;
- a plurality of interdigital transducers formed on said substrate;
- and
- reflectors formed on said substrate and sandwiching said interdigital transducers therebetween, said interdigital transducers and said reflectors comprising elongated electrode fingers, thickness h of said fingers being such that 0.06≦h/λ≦0.10 where λ is the wavelength of surface acoustic wave adapted to be generated by said filter, the fingers of said interdigital transducers having width M and being arranged at a constant pitch of P, M/P being a constant equal to or greater than 0.6, the ratio of passband width to center frequency of said filter being greater than 0.03.
1 more element
A surface acoustic wave filter comprising:
- a 36° Y-X LiTaO3 substrate;
- and
- a plurality of filter sections formed parallel and cascaded to one another on said substrate, each of said filter sections comprising a plurality of interdigital transducers formed on said substrate and reflectors which are formed on said substrate and sandwich said interdigital transducers therebetween, said interdigital transducers and said reflectors comprising elongated electrode fingers, thickness h of said fingers being such that 0.06≦h/λ≦0.10 where λ is the wavelength of surface acoustic wave adapted to be generated by said filter, the fingers of said interdigital transducers having width M and being arranged at a constant pitch of P, M/P being a constant equal to or greater than 0.6, the ratio of passband width to center frequency of said filter being greater than 0.03.
A surface acoustic wave filter comprising:
- a piezoelectric substrate;
- a plurality of interdigital transducers formed on said substrate;
- and
- reflectors formed on said substrate and sandwiching said interdigital transducers therebetween, said interdigital transducers and said reflectors comprising elongated electrode fingers, a thickness h of said fingers being such that 0.06≦h/λ≦0.10 where λ is the wavelength of surface acoustic wave adapted to be generated by said filter, the fingers of said interdigital transducers having width M and being arranged at a constant pitch of P, M/P being a constant equal to or greater than about 0.6, the ratio of passband width to center frequency of said filter being greater than about 0.03.
1 more element
A surface acoustic wave filter comprising:
- a piezoelectric substrate;
- and
- a plurality of filter sections formed parallel and cascaded to one another on said substrate, each of said filter sections comprising a plurality of interdigital transducers formed on said substrate and reflectors which are formed on said substrate and reflectors which are formed on said substrate and sandwich said interdigital transducers therebetween, said interdigital transducers and said reflectors comprising elongated electrode fingers, thickness h of said fingers being such that 0.06≦h/λ≦0.10 where λ is the wavelength of surface acoustic wave adapted to be generated by said filter, the fingers of said interdigital transducers having width M and being arranged at a constant pitch of P, M/P being a constant equal to or greater than about 0.6, the ratio of passband width to center frequency of said filter being greater than about 0.03.
A surface acoustic wave filter comprising:
- a LiTaO3 substrate;
- a plurality of interdigital transducers formed on said substrate;
- and
- reflectors formed on said substrate and sandwiching said interdigital transducers therebetween, said interdigital transducers and said reflectors comprising elongated electrode fingers, a thickness h of said fingers being such that 0.06≦h/λ≦0.10 where λ is the wavelength of surface acoustic wave adapted to be generated by said filter, the fingers of said interdigital transducers having width M and being arranged at a constant pitch of P, M/P being a constant equal to or greater than about 0.6, the ratio of passband width to center frequency of said filter being greater than about 0.03.
1 more element
A surface acoustic wave filter comprising:
- a LiTaO3 substrate;
- a plurality of filter sections formed parallel and cascaded to one another on said substrate, each of said filter sections comprising a plurality of interdigital transducers formed on said substrate and reflectors which are formed on said substrate and reflectors which are formed on said substrate and sandwich said interdigital transducers therebetween, said interdigital transducers and said reflectors comprising elongated electrode fingers, thickness h of said fingers being such that 0.06≦h/λ≦0.10 where λ is the wavelength of surface acoustic wave adapted to be generated by said filter, the fingers of said interdigital transducers having width M and being arranged at a constant pitch of P, M/P being a constant equal to or greater than about 0.6, the ratio of passband width to center frequency of said filter being greater than about 0.03.
Dependencies are inferred from the claim text.