Patent ID: 6836197
Filing Date: 2004-12-28
Classification: H03H

Abstract:
A dual track surface acoustic wave (SAW) reflective filter for filtering an input signal, said filter comprising:a substrate; a first track including a first input transducer, a first output transducer and a first reflector formed on the substrate, said first input transducer being responsive to the input signal and generating surface acoustic waves that propagate along the substrate, said first output transducer being responsive to the surface acoustic waves from the first input transducer and generating an electrical output signal; and a second track including a second input transducer, a second output transducer and a second reflector formed on the substrate, said second input transducer being responsive to the input signal and generating surface acoustic waves that propagate along the substrate, said second output transducer being responsive to the surface acoustic waves from the second input transducer and generating an electrical output signal, said first reflector and said second reflector having reflection functions that are equal in magnitude and opposite in phase, and wherein a portion of the surface acoustic waves generated by the first input transducer that are reflected by the first reflector and are received by the first output transducer are combined with a portion of the surface acoustic waves generated by the second input transducer that are reflected by the second reflector and are received by the second output transducer.