Surface acoustic wave pressure gauge

The present invention relates to a pressure gauge of the type comprising a piezoelectric substrate one face of which is polished and carried two delay lines using interdigital combs forming part of two oscillators whose output signals are mixed. The gauge comprises a two-part case communicating with a pressure gauge inlet, a piezoelectric wafer fixed by its edges to a support, the whole forming a sealed dividing wall with respect to the fluid contained in the inlet, this latter exerting its pressure on the non-polished face of the wafer. A printed circuit carrying the required electronic circuits is connected to the delay lines and inserted between the two parts of the case. A protection device may be provided for avoiding contact between the polished face and polluted air, while maintaining constant pressure on this face.