Acoustic wave amplification system

Claim 2

A solid-state acoustic-wave amplification system comprising: a piezoelectric medium propagative of acoustic waves; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; and a series of field effect transistors comprised of a source of power, a strip of semiconductive material in parallel relation to said piezoelectric medium, and a plurality of electrodes connected to said source and disposed transversely of both said semiconductive strip and said medium in coupling relation thereto with all but the first and last of said electrodes individually constituting the source connection for one and the drain connection for the next transistor of said series for delivering energy from said source to said acoustic waves.

Claim 3

A solid-state acoustic-wave amplification system comprising: a piezoelectric medium propagative of acoustic waves; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; and a series of field effect transistors comprised of a source of power, a strip of semiconductive material in parallel relation to said piezoelectric medium, and a plurality of electrodes connected to said source and disposed transversely of both said semiconductive strip and said medium in coupling relation thereto with all but the first and last of said electrodes individually constituting the source connection for one and the drain connection for the next transistor of said series for delivering energy from said source to said acoustic waves.

Claim 4

A solid-state acoustic-wave amplification system comprising: a piezoelectric medium propagative of acoustic waves; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; and a series of field effect transistors comprised of a source of power, a strip of semiconductive material in parallel relation to said piezoelectric medium, and a plurality of electrodes connected to said source and disposed transversely of both said semiconductive strip and said medium in coupling relation thereto with all but the first and last of said electrodes individually constituting the source connection for one and the drain connection for the next transistor of said series for delivering energy from said source to said acoustic waves.

Claim 5

A system as defined in claim 1 in which one end of each of said electrodes is in ohmic contact with said semiconductive strip.

Claim 6

A system as defined in claim 1 in which said electrodes are in ohmic contact with said semiconductive strip and in which said source causes movement of charge carriers in said strip parallel to said path, in the direction of propagation of said acoustic waves, and at a velocity greater than that oF said acoustic waves.

Claim 7

A system as defined in claim 1 in which said semiconductive strip is disposed within said path of acoustic wave propagation in said medium.

Claim 8

A system as defined in claim 4 in which said electrodes are also disposed in said path and extend from both sides of said strip.

Claim 9

A system as defined in claim 5 in which said electrodes have a narrow neck portion superposed over said semiconductive strip and widened portions extending from both sides of said strip.

Claim 10

A system as defined in claim 6 in which the widened portions of said electrodes are spaced from the adjacent electrodes by an amount approximately equal to the width of said widened portions.

Claim 11

A system as defined in claim 1 which includes a second plurality of electrodes interleaved with the electrodes of the first-mentioned plurality and constituting the gate connection of respective ones of said transistors.

Claim 12

A system as defined in claim 8 in which a second and similar semiconductive strip is disposed along said medium, and in which both of said pluralities of electrodes extend in coupling relation over both of said strips to define therewith two series of field effect transistors with an electrode constituting the aforesaid source-drain connections in one transistor series constituting the drain connection in the other transistor series and vice versa.

Claim 13

A solid-state acoustic wave amplification system comprising: a piezoelectric medium propagative of acoustic waves; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; and acoustic wave amplifying means, comprising: a semiconductive medium, electrically conductive coupling means coupling said piezoelectric medium and said semiconductive medium, said coupling means being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation, and means for connecting said semiconductive medium to a source of D.C. voltage for establishing a carrier drift velocity in said semiconductive medium which is effectively greater than the phase velocity of said acoustic waves in said piezoelectric medium such that traveling waves developed in said piezoelectric medium are amplified.

Claim 14

A solid-state acoustic wave amplification system comprising: a piezoelectric medium propagative of acoustic waves; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; and acoustic wave amplifying means, comprising: a semiconductive medium, electrically conductive coupling means coupling said piezoelectric medium and said semiconductive medium, said coupling means being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation, and means for connecting said semiconductive medium to a source of D.C. voltage for establishing a carrier drift velocity in said semiconductive medium which is effectively greater than the phase velocity of said acoustic waves in said piezoelectric medium such that traveling waves developed in said piezoelectric medium are amplified.

Claim 15

The system defined by claim 10 wherein said coupling means comprises a plurality of spaced electrically conductive electrodes.

Claim 16

The system defined by claim 11 including means for electrically insulating at least some of said electrodes disposed at periodic intervals along said piezoelectric medium from said semiconductive medium to establish a field effect transistor action in said semiconductive medium.

Claim 17

The system defined by claim 11 including means for insulating said electrodes from said semiconductive medium to establish field effect transistor action in said semiconductive medium.

Claim 18

A solid-state acoustic wave amplification system comprising: a piezoelectric medium propagative of acoustic waves; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; and acoustic wave amplifying means, comprising: a semiconductive medium, electrically conductive coupling means coupling said piezoelectric medium and said semiconductive medium, said coupling means being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation, insulating means for insulating said coupling means from said semiconductive medium to establish field effect transistor action in said semiconductive medium, and means for connecting said semiconductive medium to a source of D.C. voltage for establishing a carrier drift velocity in said semiconductive medium which is effectively greater than the phase velocity of said acoustic waves in said piezoelectric medium such thaT traveling waves developed in said piezoelectric medium are amplified.

Claim 19

A solid-state acoustic wave amplification system comprising: a piezoelectric medium propagative of acoustic waves; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; and acoustic wave amplifying means, comprising: a semiconductive medium, electrically conductive coupling means coupling said piezoelectric medium and said semiconductive medium, said coupling means being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation, insulating means for insulating said coupling means from said semiconductive medium to establish field effect transistor action in said semiconductive medium, and means for connecting said semiconductive medium to a source of D.C. voltage for establishing a carrier drift velocity in said semiconductive medium which is effectively greater than the phase velocity of said acoustic waves in said piezoelectric medium such thaT traveling waves developed in said piezoelectric medium are amplified.

Claim 20

The system defined by claim 14 wherein said coupling means comprises a plurality of periodically spaced electrodes.

Claim 21

The system defined by claim 15 wherein the spacing between said electrodes is no greater than one-third of the period of the highest frequency acoustic wave to be amplified.

Claim 22

The system defined by claim 15 wherein said piezoelectric medium has a permittivity which is lower than is required for optimum acoustic wave amplification, and wherein the ratio of the transverse width WL of a portion of each of said electrodes which is interfaced with said piezoelectric medium to the transverse width WS of a portion of each of said electrodes which is interfaced with said semiconductive medium is selected to correspond to a desired increase in the permittivity of said piezoelectric medium.

Claim 23

The system defined by claim 15 wherein said semiconductive medium is disposed upon a substrate spaced from said piezoelectric medium.

Claim 24

The system defined by claim 18 wherein said electrodes converge from said piezoelectric medium toward said semiconductive medium so that said semiconductive medium may have an overall length substantially less than said piezoelectric medium.

Claim 25

A solid-state acoustic wave amplification system comprising: a semiconductive medium a piezoelectric medium propagative of acoustic waves having a permittivity which in association with said semiconductive medium is different from that which is required for optimum acoustic wave amplification; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; electrically conductive coupling means coupling said piezoelectric medium and said semiconductive medium, said coupling means being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation, the ratio of the transverse width WL of or portion of said coupling means interfaced with said piezoelectric medium to the transverse width WS of a portion of said coupling means interfaced with said semiconductive medium being selected to correspond to a desired change in the permittivity of said piezoelectric medium; insulating means for insulating said coupling means from said semiconductive medium to establish field effect transistor action in said semiconductive medium; and means for connecting said semiconductive medium to a source of DC voltage for establishing a carrier drift velocity in said semiconductive medium which is effectively greater than the phase velocity of said acoustic waves in said piezoelectric medium such that traveling waves developed in said piezoelectric medium are amplifed.

Claim 26

A solid-state acoustic wave amplification system comprising: a semiconductive medium a piezoelectric medium propagative of acoustic waves having a permittivity which in association with said semiconductive medium is different from that which is required for optimum acoustic wave amplification; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; electrically conductive coupling means coupling said piezoelectric medium and said semiconductive medium, said coupling means being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation, the ratio of the transverse width WL of or portion of said coupling means interfaced with said piezoelectric medium to the transverse width WS of a portion of said coupling means interfaced with said semiconductive medium being selected to correspond to a desired change in the permittivity of said piezoelectric medium; insulating means for insulating said coupling means from said semiconductive medium to establish field effect transistor action in said semiconductive medium; and means for connecting said semiconductive medium to a source of DC voltage for establishing a carrier drift velocity in said semiconductive medium which is effectively greater than the phase velocity of said acoustic waves in said piezoelectric medium such that traveling waves developed in said piezoelectric medium are amplifed.

Claim 27

The system defined by claim 20 wherein said coupling means comprises a plurality of periodically spaced electrodes, the spacing between said electrodes being no greater than one-third of the period of the highest frequency acoustic wave to be amplified.

Claim 28

The system defined by claim 21 wherein said semiconductive medium is disposed upon a substrate spaced from said piezoelectric medium.

Claim 29

The system defined by claim 22 wherein said electrodes converge from said piezoelectric medium toward said semiconductive medium so that said semiconductive medium may have an overall length substantially less than said piezoelectric medium.

Claim 30

The system defined by claim 21 in the form of a laminate comprising at least the following layers in the order named: said piezoelectric medium acting as a substrate, said electrodes oriented transverse to the direction of acoustic wave propagation, said insulating means in the form of a thin layer, and said semiconductive medium in the form of a narrow strip oriented in the effective direction of acoustic wave propagation.

Claim 31

A solid-state acoustic wave amplification system comprisinG a piezoelectric medium capable of propagating acoustic waves at a nominal velocity Vo and having a predetermined permittivity epsilon o ; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; a semiconductive medium having a predetermined film resistivity gamma ; means for connecting said semiconductive medium to a source of D.C. voltage for establishing a carrier drift velocity Vc in said semiconductive medium; electrically conductive coupling means coupling said piezoelectric medium and said semiconductive medium such that said piezoelectric medium appears to have an effective permittivity epsilon e - theta sigma / gamma Vo , where gamma - (Vc - Vo)/Vo , said coupling means being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation.

Claim 32

A solid-state acoustic wave amplification system comprisinG a piezoelectric medium capable of propagating acoustic waves at a nominal velocity Vo and having a predetermined permittivity epsilon o ; means responsive to an input signal for launching acoustic waves along a path in said medium; means responsive to said acoustic waves for developing an output signal; a semiconductive medium having a predetermined film resistivity gamma ; means for connecting said semiconductive medium to a source of D.C. voltage for establishing a carrier drift velocity Vc in said semiconductive medium; electrically conductive coupling means coupling said piezoelectric medium and said semiconductive medium such that said piezoelectric medium appears to have an effective permittivity epsilon e - theta sigma / gamma Vo , where gamma - (Vc - Vo)/Vo , said coupling means being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation.

Claim 33

The system defined by claim 25 wherein said coupling means comprises a plurality of periodically spaced electrically conductive electrodes arranged transverse to the direction of acoustic wave propagation.

Claim 34

The system defined by claim 24 including means for electrically insulating said electrodes from said semiconductive medium to establish field effect transistor action in said semiconductive medium.

Claim 35

A laminate solid-state acoustic wave amplification system comprising, in stacked relationship: a piezoelectric medium propagative of acoustic waves and adapted to receive at spaced points thereon input and output acoustic transducers, said medium having a permittivity which is substantially less than is required for optimum amplification; a field effect transistor amplifier for amplifying acoustic waves traveling in said piezoelectric medium, comprising: a plurality of periodically spaced, electrically conductive coupling electrodes supported by said piezoelectric medium and electrically coupled thereto and being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation, said electrodes being oriented transverse to the direction of acoustic wave propagation; a strip of semiconductive material oriented in the direction of acoustic wave propagation, said strip being adapted for connection to a source of DC voltage, the width of said coupling electrodes being substantially greater than the width of said strip of semiconductive material in a direction transverse to the effective direction of acoustic wave propagation; a thin insulating layer separating said semiconductive strip from said coupling electrodes; and a source of DC voltage for establishing a carrier drift velocity in said semiconductive strip which is effectively greater than the phase velocity of said acoustic waves such that traveling waves developed in said piezoelectric medium are amplified.

Claim 36

A laminate solid-state acoustic wave amplification system comprising, in stacked relationship: a piezoelectric medium propagative of acoustic waves and adapted to receive at spaced points thereon input and output acoustic transducers, said medium having a permittivity which is substantially less than is required for optimum amplification; a field effect transistor amplifier for amplifying acoustic waves traveling in said piezoelectric medium, comprising: a plurality of periodically spaced, electrically conductive coupling electrodes supported by said piezoelectric medium and electrically coupled thereto and being substantially more conductive in the direction of coupling than in the direction of acoustic wave propagation, said electrodes being oriented transverse to the direction of acoustic wave propagation; a strip of semiconductive material oriented in the direction of acoustic wave propagation, said strip being adapted for connection to a source of DC voltage, the width of said coupling electrodes being substantially greater than the width of said strip of semiconductive material in a direction transverse to the effective direction of acoustic wave propagation; a thin insulating layer separating said semiconductive strip from said coupling electrodes; and a source of DC voltage for establishing a carrier drift velocity in said semiconductive strip which is effectively greater than the phase velocity of said acoustic waves such that traveling waves developed in said piezoelectric medium are amplified.