Surface acoustic wave filter with first and second filter tracks and balanced or unbalanced terminals

摘要

A surface acoustic wave filter. The filter includes two filter tracks which are parallel to each other. Each track has an input interdigital transducer, reflector and output interdigital transducer. This distance between the input transducer and output transducer is the same in both tracks. The distance between the output transducer and reflector is different in the two tracks. The electrical connection is in opposite phase in either the inputs or outputs, but not both. Electrode fingers are arranged in groups of two and have widths and spacings related to the wavelength.