Surface acoustic wave filter

A surface acoustic wave filter, comprising:

• a piezoelectric substrate;
• an exciting electrode formed on the piezoelectric substrate and exciting a surface acoustic wave;
• and
• a receiving electrode receiving the surface acoustic wave,
• wherein both the exciting and receiving electrodes are provided with interdigital electrode fingers having a period of p,
• the interdigital electrode fingers of either one of the exciting and receiving electrodes are each constructed to have a bend at a center for provided a shift of (n±¼)p, wherein n is an integer, in a direction parallel to a propagation direction of the surface acoustic wave, and
• the interdigital electrode fingers of the other one of the exciting and receiving electrodes extend without bending in a direction perpendicular to the propagation direction of the surface acoustic wave.

A surface acoustic wave filter comprising:

• a piezoelectric substrate;
• an exciting electrode formed on the piezoelectric substrate and exciting a surface acoustic wave;
• and
• a receiving electrode receiving the surface acoustic wave,
• wherein both the exciting and receiving electrodes are provided with interdigital electrode fingers having a period of p,
• the interdigital electrode fingers of either one of the exciting and receiving electrodes are each constructed to have a bend at a center for providing a shift of (n±¼)p, wherein n is an integer, in a direction parallel to a propagation direction of the surface acoustic wave,
• the interdigital electrode fingers of the other one of the exciting and receiving electrodes extend without bending in a direction perpendicular to the propagation direction of the surface acoustic wave, and
• said other one of the exciting and receiving electrodes is composed of a plurality of interdigital electrode sub-units having substantially the same electrode surface areas occupied by the interdigital electrode fingers, the interdigital electrode sub-units being arranged in the direction perpendicular to the propagation direction of the surface acoustic wave.

A surface acoustic wave filter comprising:

• a piezoelectric substrate;
• an exciting electrode formed on the piezoelectric substrate and exciting a surface acoustic wave;
• and
• a receiving electrode receiving the surface acoustic wave,
• wherein both the exciting and receiving electrodes are provided with interdigital electrode fingers having a period of p, and
• the interdigital electrode fingers of the exciting and receiving electrodes are constructed to have a bend at a center and are offset by (n±¼)p, wherein n is an integer, in a direction parallel to a propagation direction of the surface acoustic wave.