Surface acoustic wave functional device

A surface acoustic wave functional element comprising:

• an input electrode;
• a reference signal input electrode;
• a semiconductor layer provided on a piezoelectric substrate and grating electrodes for conveying a surface acoustic wave to said semiconductor layer, wherein
• said semiconductor layer is situated outside above a propagation path of a surface acoustic wave propagating from said input electrode and said reference signal input electrode, said semiconductor layer is composed of an active layer and a buffer layer lattice-matching thereto, a plurality of said grating electrodes are placed on said propagation path perpendicularly to the propagation direction and in a greater width than that of the propagation path, and two input signals propagating from said reference signal input electrode and said input electrode are subjected to convolution so as to be outputted from an output electrode and an output ground electrode.

A surface acoustic wave functional element comprising:

• a semiconductor layer;
• and
• a plurality of grating electrodes for conveying a surface acoustic wave to the semiconductor layer provided on a piezoelectric substrate or on a piezoelectric film substrate, wherein
• said semiconductor layer is situated outside above a propagation path through which a surface acoustic wave propagates, said grating electrodes are formed perpendicularly to the propagating direction above said semiconductor layer, a strip dielectric film is formed at the top of a portion of the grating electrodes opposed to said semiconductor layer across said propagation path and an output electrode is formed on the strip dielectric film.