Patent ID: 8695428

Claim:
A surface acoustic wave device comprising: a piezoelectric substrate; a single input inter-digital transducer disposed on the piezoelectric substrate, the input inter-digital transducer converting a first electrical signal into a surface acoustic wave signal; a plurality of output inter-digital transducers disposed on the piezoelectric substrate, the output inter-digital transducers converting the surface acoustic wave signal into a second electrical signal; and a delay line between the input inter-digital transducer and the output inter-digital transducers, wherein at least two of the output inter-digital transducers are arranged in a row parallel to a longitudinal direction of the input inter-digital transducer, and the input inter-digital transducer includes fingers; each finger having a length such that an insertion loss of the input inter-digital transducer represented by Formula (1) and (2) below is less than −30 dB: IL=− 20 log | Y| (1) Y=Y 0 ( W /λ) (2) where IL is insertion loss, Y is total input admittance, and Y 0 is characteristic admittance, λ is a wave length and W is a finger length.