Duplexer with an impedance matching circuit and an electronic device using the same

1. A duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package; and

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package,

a first ground pattern with respect to the phase matching line being provided on a mount surface of the multilayer package,

a first distance between the phase matching line and the first ground pattern at a position just below the SAW filters being greater than a second distance between the phase matching line and an inner ground pattern provided in the multilayer package at a position that is further out than the SAW filters in a lateral direction of the duplexer.

2. The duplexer according to claim 1 , wherein the first ground pattern is formed so as to face at least part of the phase matching line.

3. The duplexer according to claim 1 , further comprising a second ground pattern provided on a chip mount surface of the multilayer package, the phase matching line being interposed between the first and second ground pattern.

4. The duplexer according to claim 1 , wherein:

a multilayer package has a cap attachment surface; and

the phase matching line is interposed between the first ground pattern and the cap attached to the cap attachment surface.

5. The duplexer according to claim 1 , wherein the SAW filters are formed on a single filter chip.

6. A duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package; and

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package,

a plurality of ground patterns with respect to the phase matching line being provided at a first side of the multilayer package opposite to a second side thereof at which the SAW filters are provided.

7. The duplexer according to claim 6 , wherein one of the plurality of ground patterns is provided in the multilayer package.

8. The duplexer according to claim 6 , wherein the plurality of ground patterns are connected to form common ground.

9. The duplexer according to claim 6 , wherein one of the plurality of ground patterns is provided on a mount surface of the multilayer package.

10. The duplexer according to claim 6 , wherein the plurality of ground patterns are electrically connected via connecting parts provided in the multilayer package.

11. An electronic device comprising a duplexer and a circuit board,

the duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package; and

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package,

a first ground pattern with respect to the phase matching line being provided on a mount surface of the multilayer package,

a first distance between the phase matching line and the first ground pattern at a position just below the SAW filters being greater than a second distance between the phase matching line and an inner ground pattern provided in the multilayer package at a position that is further out than the SAW filters in a lateral direction of the duplexer.

12. A duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package; and

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package;

a first ground pattern that underlies the SAW filters;

a second ground pattern that has an opening formed so as to face the first ground pattern and is provided in the multilayer package;

a third ground pattern that is provided on a mount surface of the multilayer package and faces the opening of the second ground pattern; and

a cap provided on the multilayer package,

ground with respect to the phase matching line being provided by a combination of the first and third ground patterns and another combination of the second ground pattern and the cap.

13. The duplexer according to claim 12 , wherein the opening and the first ground pattern have a substantially identical shape.

14. The duplexer according to claim 12 , wherein the opening and the third ground pattern have a substantially identical shape.

15. The duplexer according to claim 12 , wherein the first, second and third ground patterns are commonly connected.

16. A duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package;

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package;

a first ground pattern that underlies the SAW filters;

a second ground pattern that has an opening formed so as to face the first ground pattern and is provided in the multilayer package; and

a cap provided on the multilayer package,

ground with respect to the phase matching line being provided by a combination of the second ground pattern and the cap and another combination of the first ground pattern and a conductive pattern on a board on which the duplexer is mounted.

17. A duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package; and

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package;

ground with respect to the phase matching line being provided by a ground pattern provided on a mount surface of the multilayer package and a cap provided on the multilayer package,

a first distance between the phase matching line and the first ground pattern at a position just below the SAW filters being greater than a second distance between the phase matching line and an inner ground pattern provided in the multilayer package at a position that is further out than the SAW filters in a lateral direction of the duplexer.

18. The duplexer according to claim 17 , wherein the ground with respect to the phase matching line is further provided by the ground pattern and a conductive layer that underlies the SAW filters.

19. A duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package; and

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package;

a ground layer with respect to the phase matching line being provided so that at least two of layers forming the multilayer package are interposed between the phase matching line and the ground layer, the ground layer being provided on a bottom of the multilayer package.

20. The duplexer according to claim 19 , wherein the ground layer includes a ground pattern provided on a mount surface of the multilayer package and a cap attached to the multilayer package.

21. A duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package; and

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package;

ground with respect to the phase matching line being provided by a first combination of ground patterns and a second combination of ground patterns so that the phase matching line is interposed between the first combination of ground patterns and the second combination of ground patterns, the ground patterns of the first combination being different from those of the second combination.

22. A duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package; and

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package,

a plurality of ground patterns with respect to the phase matching line being provided at a first side of the multilayer package opposite to a second side thereof at which the SAW filters are provided, wherein:

the plurality of ground patterns include a first conductive layer provided on a mount surface of the multilayer package, and a second conductive layer provided in the multilayer package; and

the second conductive layer has an opening through which the first conductive layer faces the phase matching line.

23. The duplexer according to claim 22 , wherein the opening and the first conductive layer have substantially identical shape.

24. A electronic device comprising an antenna, a duplexer connected thereto, and a transmit/receive circuit connected to the duplexer,

the duplexer comprising:

a multilayer package;

SAW (Surface Acoustic Wave) filters that have different band center frequencies and are provided in the multilayer package; and

a phase matching line that matches phases of the SAW filters and are provided in the multilayer package,

a first ground pattern with respect to the phase matching line being provided on a mount surface of the multilayer package,

a first distance between the phase matching line and the first ground pattern at a position just below the SAW filters being greater than a second distance between the phase matching line and an inner ground pattern provided in the multilayer package at a position that is further out than the SAW filters in a lateral direction of the duplexer.