Patent ID: 6441704
Filing Date: 2002-08-27
Classification: H03H

Abstract:
A surface acoustic wave filter that can be operated symmetrically, comprising:an input IDT transducer; an output IDT transducer; at least one of said IDT transducers being electromagnetically coupled and split into partial transducers, said IDT transducers having electrical connection pads and ports, at least one pair of said partial transducers connected in parallel, said partial transducers and said electrical connection pads disposed to make, in the case of symmetric operation, crosstalk capacitances between adjacent ones of said pads and said IDT transducers approximately equal in amount at a corresponding one of said ports and at voltages of opposite polarity for balancing the crosstalk capacitances; a first magnetic coupling being disposed between said at least one pair of said partial transducers connected in parallel and having a first direction; and a second magnetic coupling being disposed between an adjacent pair of said partial transducers, having a second direction opposing the first direction, and making a total induced magnetic flux equal to zero for said electromagnetically coupled IDT transducers.