Epcos Ag

Snaptrack Incorporated

Jacques Antoine Damy

Holger Emrich

Christian Waterkeyn

Heiko Hartmann

Raphael Lardat

Mohamed Elhakiki

Michel Peracchia

A filter working with surface acoustic waves comprises a piezoelectric substrate (SU), a first transducer (IDT) arranged in the acoustic track coupled to an input, having a first mean finger period (pi) assigned to a center frequency of a pass band of the filter and a second transducer (IDT) arranged in the acoustic track coupled to an output, having the same first mean finger period (p), and a reflector arranged between first and second transducer having a second mean finger period (p) assigned to a stop band frequency different from the center frequency. Further, a new type of very broad bandwidth filters with small insertion loss and high return loss and high rejection are given that use a substrate that can propagate a PSAW and comprises fan shaped transducers.

Saw filter with improved stop band suppression

A new type of very broad bandwidth filters with small insertion loss and high return loss are given. The new filter uses a substrate that can propagate a PSAW and fan shaped transducers of low metallisation height, high metallisation ratio, low reflectivity and high coupling coefficient.

Broadband SAW filter

The filter includes at least one acoustic track formed on a piezoelectric substrate. At least one SAW input transducer and at least one SAW output transducer are arranged in each track. Each track has a RSPUDT structure and thus a distributed excitation. The excitation function includes sources arranged in a main lobe and a tail function including at least one tail lobe. A fine and precise approximation to the desired continuous excitation function is obtained by decreasing the excitation strength in the tail function by a factor of at least 2.

Transversal filter

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Nice, France

Jacques Antoine Damy