Unilateral surface wave transducer

Claim 2

A unilateral surface wave transducer, comprising: an alignment, in alternating succession, of transmitter cells and reflector cells, separated by conventional left-hand and right-hand boundaries; wherein each transmitter cell is capable of transmission, by its left-hand and right-hand boundaries, of the waves in a phase opposition, and each reflector cell has, at each of its left-hand and right-hand boundaries, coefficients of reflection in phase opposition; wherein the transmitter cells are formed by two electrodes in the form of interdigitated combs having a pitch equal to λ/3; λ being the working center wavelength of the transducer; and wherein the left-hand boundary of a transmitter cell is located along the external edge of the tooth furthest to the left of this cell and wherein the right-hand boundary is located at a distance equal to λ/6 from the external edge of the tooth furthest to the right of the cell, the width of the teeth being λ/6.

Claim 3

A unilateral surface wave transducer, comprising: an alignment, in alternating succession, of transmitter cells and reflector cells, separated by conventional left-hand and right-hand boundaries, wherein each transmitter cell is capable of transmission, by its left-hand and right-hand boundaries of the waves in phase opposition, and each reflector cell has, at each of its left-hand and right-hand boundaries, coefficients of reflection in phase opposition; and wherein each reflector cell includes a set of elementary reflectors arranged according to an elementary pitch equal to λ/2, the left-hand boundary of the cell being located along the external edge of the elementary reflector furthest to the left, and the right-hand boundary of the cell being located at a distance equal to λ/4 from the external edge of the reflector furthest to the right; each reflector having a width equal to λ/4.

Claim 4

A unilateral surface wave transducer, comprising: an alignment, in alternating succession, of transmitter cells and reflector cells, separated by conventional left-hand and right-hand boundaries, wherein each transmitter cell is capable of transmission, by its left-hand and right-hand boundaries of the waves in phase opposition, and each reflector cell has, at each of its left-hand and right-hand boundaries, coefficients of reflection in phase opposition; and wherein each reflector cell includes a set of elementary reflectors arranged according to an elementary pitch equal to λ/2, the left-hand boundary of the cell being located along the external edge of the elementary reflector furthest to the left, and the right-hand boundary of the cell being located at a distance equal to λ/4 from the external edge of the reflector furthest to the right; each reflector having a width equal to λ/4.

Claim 5

A transducer according to claim 2, wherein the elementary reflectors are insulated electrodes.

Claim 6

A transducer according to claim 2, wherein the elementary reflectors are short-circuited electrodes.

Claim 7

A unilateral surface wave transducer comprising: an alignment, in alternating succession, of transmitter cells and reflector cells, separated by conventional left-hand and right-hand boundaries, wherein each transmitter cell is capable of transmission, by its left-hand and right-hand boundaries, of the waves in phase opposition, and each reflector cell has, at each of its left-hand and right-hand boundaries, coefficients of reflection in phase opposition; wherein the transmitter cells are formed by two electrodes in the form of interdigitated combs having a pitch equal to λ/3; λ being the working center wavelength of the transducer; and wherein the left-hand boundary of a transmitter cell is located at a distance smaller than λ/6 from the external edge of the tooth furthest to the left of this cell, and the right-hand boundary is located at a distance smaller than λ/6 from the external edge of the tooth furthest to the right of the cell; the width of the teeth being λ/6.

Claim 8

A unilateral surface wave transducer comprising: an alignment, in alternating succession, of transmitter cells and reflector cells, separated by conventional left-hand and right-hand boundaries, wherein each transmitter cell is capable of transmission, by its left-hand and right-hand boundaries, of the waves in phase opposition, and each reflector cell has, at each of its left-hand and right-hand boundaries, coefficients of reflection in phase opposition; wherein the transmitter cells are formed by two electrodes in the form of interdigitated combs having a pitch equal to λ/3; λ being the working center wavelength of the transducer; and wherein the left-hand boundary of a transmitter cell is located at a distance smaller than λ/6 from the external edge of the tooth furthest to the left of this cell, and the right-hand boundary is located at a distance smaller than λ/6 from the external edge of the tooth furthest to the right of the cell; the width of the teeth being λ/6.