Surface acoustic wave filter

A surface acoustic wave filter, comprising:

• a piezoelectric substrate;
• an interdigital electrode having a plurality of electrode fingers formed on said substrate, said electrode fingers being interdigited and defining a plurality of pairs of adjacent electrode fingers which cooperate to generate a surface acoustic wave which propagates in a predetermined direction along said substrate when a predetermined set of potentials is applied to said electrode, said surface acoustic wave having a central frequency f and having both a symmetrical and an asymmetrical component;
• said interdigital electrode being divided into first and second portion electrodes disposed in a row extending in said direction, said portion electrodes being electrically connected in series, a first electrode finger defining part of said first portion electrode and a second electrode finger defining part of said second electrode finger being adjacent to each other and at different potentials;
• said first electrode finger having a deformed portion extending towards said second electrode finger such that a first portion of said first electrode finger is a first distance from said second electrode finger as measured along said predetermined direction and a second portion, which forms part of said deformed portion, of said electrode finger is a second distance, less than said first distance, from said second electrode finger as measured along said predetermined direction.