Transducer structure (1; 21; 31; 41) for converting a deformation along an axis into a corresponding deformation on a plane orthogonal to said axis, comprising: - two end plates (2, 3) facing each other and aligned along a common reference axis; - a plurality of connection members projecting radially from each end plate (2, 3) according to respective mutually different directions; - a plurality of lateral bars, each connecting said end plates (2, 3) to one another through two respective of said connection members; wherein said connection members are deformable within respective deformation planes to allow relative movements between said end plates (2, 3) and said lateral bars such as to convert an axial movement of mutual approach between said two end plates (2, 3) into a corresponding radial movement of said lateral bars away from said reference axis, and vice-versa, characterized in that it comprises an additional end plate facing a first one of said end plates (2, 3) and connected to said first end plate through a shear decoupling unit having a smaller stiffness under a deformation orthogonal to said reference axis than under a deformation parallel to said reference axis to allow relative movements between said additional end plate and said first end plate in a direction orthogonal to said reference axis while preventing said relative movements in a direction parallel to said reference axis. - two end plates (2, 3) facing each other and aligned along a common reference axis; - a plurality of connection members projecting radially from each end plate (2, 3) according to respective mutually different directions; - a plurality of lateral bars, each connecting said end plates (2, 3) to one another through two respective of said connection members; wherein said connection members are deformable within respective deformation planes to allow relative movements between said end plates (2, 3) and said lateral bars such as to convert an axial movement of mutual approach between said two end plates (2, 3) into a corresponding radial movement of said lateral bars away from said reference axis, and vice-versa, characterized in that it comprises an additional end plate facing a first one of said end plates (2, 3) and connected to said first end plate through a shear decoupling unit having a smaller stiffness under a deformation orthogonal to said reference axis than under a deformation parallel to said reference axis to allow relative movements between said additional end plate and said first end plate in a direction orthogonal to said reference axis while preventing said relative movements in a direction parallel to said reference axis. wherein said connection members are deformable within respective deformation planes to allow relative movements between said end plates (2, 3) and said lateral bars such as to convert an axial movement of mutual approach between said two end plates (2, 3) into a corresponding radial movement of said lateral bars away from said reference axis, and vice-versa, characterized in that it comprises an additional end plate facing a first one of said end plates (2, 3) and connected to said first end plate through a shear decoupling unit having a smaller stiffness under a deformation orthogonal to said reference axis than under a deformation parallel to said reference axis to allow relative movements between said additional end plate and said first end plate in a direction orthogonal to said reference axis while preventing said relative movements in a direction parallel to said reference axis.