Surface wave device having anti-reflective shield

A surface acoustic wave device, comprising:

• a base of surface acoustic wave propogative material;
• first transducer means, disposed on a surface of said base and having at least two substantially parallel electrodes of selected length less than or equal to a predetermined maximum length and one of which is grounded and located at an end of said first transducer means, for launching surface acoustic waves in a direction substantially perpendicular to said electrodes in response to an electrical signal applied between said pair of electrodes;
• second transducer means, disposed on said surface of said base, for receiving surface acoustic waves;
• and third means associated with said first transducer means, for suppressing surface acoustic waves in said device, said third means comprising at least one additional grounded electrode disposed on said surface of said base adjacent the grounded end electrode of said first transducer means and substantially parallel thereto and separated therefrom by a selected distance and having a selected length less than said grounded end electrode.

A surface acoustic wave device, comprising:

• a base of surface acoustic wave propogative material;
• first transducer means, disposed on a surface of said base, for launching surface acoustic waves;
• second transducer means, disposed on said surface of said base and having at least two substantially parallel electrodes of selected length less than or equal to a predetermined maximum length and one of which is grounded and located at an end of said second transducer means, for receiving surface acoustic waves arriving from a direction substantially perpendicular to said electrodes;
• and third means associated with said second transducer means, for suppressing surface acoustic waves in said device, said third means comprising at least one additional grounded electrode disposed on said surface of said base adjacent the grounded end electrode of said second transducer means and substantially parallel thereto and separated therefrom by a selected distance and having a selected length less than said grounded end electrode.

A surface acoustic wave device, comprising:

• a base of acoustic wave propogative material;
• first transducer means, disposed on a surface of said base and having at least three substantially parallel electrodes, each electrode having a selected length less than or equal to a predetermined maximum length, and including a grounded electrode at each end thereof, for launching acoustic surface waves in a direction substantially perpendicular to said electrodes in response to an electrical signal applied between predetermined ones of said electrodes;
• second transducer means, disposed on said surface of said base and having at least three substantially parallel electrodes, each electrode having a selected length less than or equal to said predetermined maximum length, and including a grounded electrode at each end thereof, for receiving acoustic surface waves arriving from a direction substantially perpendicular to said electrodes;
• and third means associated with said first and said second transducer means, for suppressing surface acoustic waves in said device, said third means comprising at least four pair of grounded electrodes, each pair being disposed adjacent a corresponding one of the grounded end electrodes of said first and second transducer means, said grounded end electrodes being said maximum length, the one of said pair that is closest to said grounded end electrode being 2/3 said maximum length and the other of said pair being 1/3 said maximum length.

A surface acoustic wave device, comprising:

• a base of surface acoustic wave propogative material;
• first transducer means, disposed on a surface of said base and having at least three substantially parallel electrodes, each electrode having a selected length less than or equal to a predetermined maximum length, and including a grounded electrode at each end thereof, for launching surface acoustic waves in a direction substantially perpendicular to said electrodes in response to an electrical signal applied between predetermined ones of said electrodes;
• second transducer means, disposed on said surface of said base, for receiving surface acoustic waves;
• and third means associated with said first transducer means, for suppressing surface acoustic waves in said device, said third means comprising at least two grounded electrodes disposed on said surface of said base, each of which is disposed adjacent a corresponding one of the grounded end electrodes of said first transducer means and substantially parallel thereto and separated therefrom by a selected distance and having a selected length less than the length of said corresponding grounded end electrode of said first transducer means.

A surface acoustic wave device, comprising:

• a base of surface acoustic wave propogative material;
• first transducer means, disposed on a surface of said base, for launching surface acoustic waves;
• second transducer means, disposed on said surface of said base and having at least three substantially parallel electrodes, each electrode having a selected length less than or equal to a predetermined maximum length, and including a grounded electrode at each end thereof, for receiving surface acoustic waves arriving from a direction substantially perpendicular to said electrodes;
• and third means associated with said second transducer means, for suppressing surface acoustic waves in said device, said third means comprising at least two grounded electrodes disposed on said surface of said base, each of which is disposed adjacent a corresponding one of the grounded end electrodes of said second transducer means and substantially parallel thereto and separated therefrom by a selected distance and having a selected length less than the length of said corresponding grounded end electrode of said second transducer means.