Piezoelectric filter

• US 3,189,851 A
• Filed: 06/04/1962
• Issued: 06/15/1965
• Est. Priority Date: 06/04/1962
• Status: Expired due to Term

• Current Assignee: Peter H. Fowler
• Original Assignee: Peter H. Fowler
• Inventors: Fowler, Peter H.
• Application Number:
  US04/201,724
• Time in Patent Office: 1,107 Days
• US Class Current: 333/189
• CPC Class Codes: H03H 9/581 comprising ceramic piezoelectric layers
• CPC Class Codes: H03H 9/60 Electric coupling means therefor H03H9/0095 takes precedence

Claims

1. A FILTER COMPRISING A SERIES OF AT LEAST TWO ACOUSTICAL TRANSFORMERS, EACH OF SAID TRANSFORMERS COMPRISING FIRST AND SECOND DISC-SHAPED, AXIALLY POLARIZED, PIEZOELECTRIC TRANSDUCERS HAVING OPPOSITE ELECTRODED FACES, SAID TRANSDUCERS BEING JUXTAPOSED IN CLOSELY SPACED FACE-TO-FACE RELATION, THIN BONDING MEANS INCLUDING CONDUCTING MEANS BETWEEN SAID TRANSDUCERS, SAID BONDING MEANS COVERING SUBSTANTIALLY THE ENTIRE OPPOSING FACES OF SAID TRANSDUCERS SAID BONDING MEANS EFFECTING CLOSE ACOUSTICAL COUPLING BETWEEN SAID TRANSDUCERS, EACH OF SAID TRANSDUCERS EXHIBITING AN ELECTRICAL RESONANCE AT A FIRST FREQUENCY AND A MECHANICAL RESONANCE AT A SECOND FREQUENCY, A SIGNAL SOURCE HAVING A FIRST IMPEDANCE, SAID SIGNAL SOURCE DELIVERING A SIGNAL AT A SELECTED FREQUENCY INTERMEDIATE SAID MECHANICAL AND ELECTRICAL RESONANT FREQUENCIES OF SAID TRANSDUCERS, A LOAD HAVING A SECOND IMPEDANCE LESS THAN SAID FIRST IMPEDANCE MEANS CONNECTING THE OPPOSITE ELECTRODED FACES OF SAID FIRST TRANSDUCER OF THE FIRST TRANSFORMER OF SAID SERIES TO SAID SOURCE, MEANS FOR CONNECTING THE OPPOSITE ELECTRODED FACES OF SAID SECOND TRANSDUCER OF THE LAST TRANSFORMER OF SAID SERIES TO SAID LOAD AND MEANS FOR ELECTRICALLY CONNECTING IN CASCADE THE REMAINING TRANSDUCERS OF THE FILTER.