Loading patent…
AssigneeAdvanced SAW Products SA
InventorsSergei N. Kondratyev, Victor P. Plessky, Clinton S. Hartmann, Thor Thorvaldsson, David P. Morgan
Estimating the term…
A SAW filter having an even number of tracks, each track comprising reflective input and output IDTs having a partially reflecting grating disposed between them. One of the IDTs of each pair of tracks has its electrodes connected in opposite polarity to those of the other IDTs of the pair of tracks and the separation of the input and output IDTs of respective tracks of each pair of tracks is substantially the same. The relative dispositions of the partially reflecting gratings are such that waves launched into respective tracks of a pair of tracks undergo at least one reflection from the partially reflecting grating prior to being coherently incident on the output IDTs. By virtue of the oppositely connected electrodes of one of the IDTs, direct coupling through the tracks is inhibited at substantially all frequencies.
A SAW filter comprising an even number N of tracks, each track including an input interdigitated transducer (IDT) spaced apart from an output IDT, a partially reflecting means disposed between the input and output IDTs and reflecting means respectively associated with the input and output IDTs, wherein electrodes of one IDT of a pair of tracks are connectable in opposite polarity relative to electrodes of other IDTs of the pair of tracks, in each pair of tracks the input and output IDTs of respective tracks are separated by substantially the same amount, and surface acoustic waves launched into respective tracks from the input IDTs undergo at least one reflection from the partially reflecting means prior to forming a substantially coherent signal at the output IDTs.
A narrow bandwidth SAW filter comprising:
In a SAW filter having a plurality of tracks of input and output interdigitated transducers (IDT), two of the tracks having electrically connected input IDTs and electrically connected output IDTs with equal spacings in their respective tracks between the input and output IDTs, wherein the improvement comprises:
Dependencies are inferred from the claim text.