In-line surface acoustic wave filter assembly module and method of making same

A method of manufacturing a filter assembly module including a pair of adjacent surface acoustic wave (SAW) filter devices each having input signal, input ground, output signal and output ground electrodes, whereby substantial isolation between the input signal and the output signal of the module and electrical contacts for associated circuitry are provided comprising:

• a. applying electrically conductive material in a pattern of a plurality of discrete mutually isolated areas on a surface of an insulative substrate having oppositely disposed input and output ends, and oppositely disposed terminal and non-terminal sides such that:
• 1. a first area is located adjacent the input end;
• 2. a second area is located adjacent the output end;
• 3. a third area is located between said first and second areas and includes a portion adjacent the terminal side of said surface;
• 4.

a fourth area is located between said third area and said non-terminal side of said surface and includes oppositely disposed input and output portions and an intermediate portion;

• 5. a fifth area is located between said first and third areas and includes a portion adjacent said terminal side of said surface;
• 6. a sixth area is located between said second and third areas and includes a portion adjacent said terminal side of said surface;
• b. placing a first surface acoustic wave filter device over a portion of the conductive material on each of said first and fifth areas and securing the device thereto;
• c. placing a second surface acoustic wave filter device over a portion of the conductive material on each of said second and sixth areas and securing the device thereto;
• d. electrically connecting the first area to the input signal electrode;
• the fifth area to the input ground electrode;
• the input portion of the fourth area to the output signal electrode;
• and the fifth area to the output ground electrode of said first surface acoustic wave filter device;
• e. electrically connecting the output portion of said fourth area to said input signal electrode, said sixth area to said input ground electrode, said sixth area to said output ground electrode, and said second area to said output signal electrode of said second surface acoustic wave filter device;
• f. electrically connecting and mechanically securing a metallic shield to said third area and positioning said shield between said surface acoustic wave filter devices for blocking radiative signals therebetween;
• and
• g. electrically connecting a coupling inductor between said third area and said intermediate portion of said fourth area to provide low insertion
• loss and high selectivity for said filter assembly module. 4. A surface acoustic wave (SAW) filter assembly module including improved isolation means comprising:
• a. an insulative substrate having oppositely disposed input and output ends and oppositely disposed terminal and non-terminal sides;
• b. a plurality of discrete mutually isolated electrically conductive areas on a surface of said substrate including:
• 1. a first area located adjacent the input end and said terminal side of said surface;
• 2. a second area located adjacent the output end and said terminal side of said surface;
• 3. a third area located between said first and second areas and including a portion thereof adjacent said terminal side of said surface;
• 4. a fourth area located between said third area and said non-terminal side of said surface and including oppositely disposed input and output portions and an intermediate portion;
• 5. a fifth area located between said first and third areas and including a portion adjacent said terminal side of said surface;
• 6. a sixth area located between said second and third areas and including a portion adjacent said terminal side of said surface;
• c. first and second surface acoustic wave filter devices, each having input and output signal electrodes and input and output ground electrodes;
• said first device being positioned over and secured to each of said first and fifth areas;
• said second device being positioned over and secured to each of said second and sixth areas;
• d. means electrically connecting:
• 1. said first area to said input signal electrode;
• 2. said fifth area to said input ground electrode;
• 3. said input portion of said fourth area to said output signal electrode;
• 4. said fifth area to said output ground electrode of said first device;
• e. means electrically connecting;
• 1. said sixth area to said input ground electrode;
• 2. said output portion of said fourth area to said input signal electrode;
• 3. said sixth area to said output ground electrode;
• 4. said second area to said output signal electrode of said second device;
• and
• f. an electrically conductive shield electrically connected to said third area and positioned between said devices for blocking radiative signals therebetween.