3. Manufacturing technology

The FOS filter structure described above (figure 1 ) is relatively simple. It comprises :

• a substrate with its pattern of metal electrodes;

• electrical connection wires ;

• an encapsulation box.

The elementary manufacturing steps are grouped into two successive parts:

• Front-End or waferfab; the production of the electrode patterns or DOS (surface wave device), defined at the design stage, is the key operation that determines the filter's ultimate performance; the photo in figure