Abstract: A resonator filter cascade has resonator structures disposed adjacent to one another and form a waveguide for acoustic surface waves, and coupling transducers. The present invention changes resonator filter cascades so that the insertion attenuation is reduced by decreasing the attenuation of cascading, without using a coupling coil. A resonator filter cascade has resonator structures having coupling transducers which transversely couple resonator filters and the coupling transducers, belonging the same transversely coupled resonator filter, are not connected with one another. Coupling transducers of different transversely coupled resonator filters are each connected with one another over a pair of electrically conducting connections.

Abstract: The invention relates to a transverse-mode-coupled resonator filter based on surface acoustic waves. The object of the invention is to modify such resonator filters, in which there are disposed adjacent to one another on a substrate (1) a plurality of one-port resonator structures (2; 3), which comprise two strip reflectors (22 and 23; 32 and 33) and an interdigital transducer (21; 31) and together form a waveguide for surface acoustic waves, in such a way that the insertion loss of the filters is reduced, especially by reducing the damping due to the cascade connection. This object is achieved by the fact that at least one of the one-port resonator structures (2; 3) differs from the other one-port resonator structures by the ratio of the finger width to the spacing (216) of the finger centers (214; 215) and by the ratio of the width of the reflector strips (221; 231; 321; 331) to the spacing (226; 236) of the centers (224; 225 and 234; 235) of the reflector strips (221; 231; 321; 331).

Abstract: The invention aims at modifying SPUDT-type surface acoustic wave filters in such a way that the wideband filter can be produced with lower insertion loss and a small form factor without substantially enlarging layout. According to the invention, this is achieved by combining the following characteristics: a) the totality of fingers (231-233; 331-333) of each transducer (2; 3) forms a tapering structure and b) the widths and the positions of the fingers are chosen in such a way that the waves reflected on the fingers (231-233; 331-333) together with the waves regenerated by the corresponding source and load resistance (8; 9) result in an lengthening of the impulse response of the filter, which reduces form factor and/or bandwidth. The invention can be used in surface acoustic wave-based components such as wideband bandpass filters and delay lines.

Abstract: The aim of the invention is to modify prior art converters for surface acoustic waves in such a way that, despite an essentially homogeneous amplitude profile, other weighting factors can also be realized as 0 or ±1. The invention considers converters of the prior art that consist of prong groups which are comprised of at least two prongs, are arranged on a piezoelectric substrate, and which are assembled to form collector electrodes. According to the invention at least some of the prong groups are constructed in such a way that they differ from the remaining prong groups with regard to the wave amplitude excited thereby.