Antenna duplexer

1. An antenna duplexer comprising:

an input terminal;

a transmission filter including a surface acoustic wave (SAW) filter having an input port connected to said input terminal;

a phase shifter having an input port connected to an output port of said transmission filter;

a reception filter having an input port connected to an output port of said phase shifter;

an output terminal connected to the output port of said reception filter; and

an antenna terminal connected between said transmission filter and said phase shifter,

wherein said transmission filter has a power durability at said output port thereof, the power durability being larger than a power durability at said input port thereof.

2. The antenna duplexer of claim 1 ,

wherein said SAW filter includes:

a substrate;

a SAW resonator disposed on said substrate; and

a conductor pattern disposed on said the substrate, said conductor pattern being connected to said SAW resonator.

3. The antenna duplexer of claim 1 ,

wherein said transmission filter includes a first SAW filter having a first series arm SAW resonator disposed at an outermost arm towards said antenna terminal, and

wherein said first series arm SAW resonator include a plurality of second series arm SAW resonators connected in series with each other.

4. The antenna duplexer of claim 3 ,

wherein the first SAW filter further includes a third series arm SAW resonator, and

wherein a series arm SAW resonator having a smallest capacitance of said second series arm SAW resonators has a capacity equal to or larger than a capacitance of said third series arm SAW resonator.

5. The antenna duplexer of claim 3 ,

wherein said first SAW filter further includes a first parallel arm SAW resonator, and

wherein said first parallel arm SAW resonator includes a plurality of second parallel arm SAW resonators connected in series with each other.

6. The antenna duplexer of claim 5 ,

wherein said first SAW filter further includes a third parallel arm SAW resonator, and

wherein said first parallel arm SAW resonator is connected closer to said antenna terminal than said third parallel arm SAW resonator.

7. The antenna duplexer of claim 6 , wherein a SAW resonator having a smallest capacitance of said second parallel arm SAW resonators has a larger capacitance than said third parallel arm SAW resonator.

8. The antenna duplexer of claim 3 , wherein said reception filter includes a second SAW filter including a third series arm SAW resonator disposed at an outermost arm towards said input terminal.

9. The antenna duplexer of claim 8 , wherein said third series arm SAW resonator includes a plurality of fourth series arm SAW resonators connected in series with each other.

10. The antenna duplexer of claim 9 ,

wherein said second SAW filter further includes a fifth series arm SAW resonator, and

wherein a SAW resonator having a smallest capacitance of said fourth series arm SAW resonators has a larger capacitance than said fifth series arm SAW resonator.

11. The antenna duplexer of claim 8 , wherein said second SAW filter further includes a first parallel arm SAW resonator including a plurality of second parallel arm SAW resonators connected in series with each other.

12. The antenna duplexer of claim 11 ,

wherein said second SAW filter further includes a third parallel arm SAW resonator, and

wherein said first parallel arm SAW resonator is disposed closer to said antenna terminal than said third parallel arm SAW resonator.

13. An antenna duplexer comprising:

an input terminal;

a transmission filter including a surface acoustic wave (SAW) filter having an input port connected to said input terminal;

a phase shifter having an input port connected to an output port of said transmission filter;

a reception filter having an input port connected to an output port of said phase shifter;

an output terminal connected to the output port of said reception filter; and

an antenna terminal connected between said transmission filter and said phase shifter,

wherein said transmission filter includes a first SAW filter having a first series arm SAW resonator disposed at an outermost arm towards said antenna terminal, and

wherein said first series arm SAW resonator includes a plurality of second series arm SAW resonators connected in series with each other.

14. The antenna duplexer of claim 13 ,

wherein said SAW filter includes:

a substrate having said plurality of second series arm SAW resonators disposed thereon;

a plurality of third series arm SAW resonators disposed on said substrate; and

a conductor pattern disposed on said substrate, said conductor pattern being connected to at least one of said third series arm SAW resonators and said plurality of second series arm SAW resonators, and

wherein a layout of said plurality of second series arm SAW resonators, said third series arm SAW resonators, and said conductor pattern are symmetrical.

15. The antenna duplexer of claim 13 , wherein said SAW filter has a circuit being identical as seen both from the input port thereof and from the output port thereof.

16. The antenna duplexer of claim 13 ,

wherein said SAW filter includes:

a substrate;

a SAW resonator disposed on said substrate; and

a conductor pattern disposed on said the substrate, said conductor pattern being connected to said SAW resonator, and

wherein a layout of said SAW resonator and conductor pattern is symmetrical.

17. The antenna duplexer of claim 13 ,

wherein the first SAW filter includes a third series arm SAW resonator; and

wherein a series arm SAW resonator having a smallest capacitance of said second series arm SAW resonators has a capacity equal to or larger than a capacitance of said third series arm SAW resonator.

18. The antenna duplexer of claim 13 ,

wherein said first SAW filter further includes a first parallel arm SAW resonator, and

wherein said first parallel arm SAW resonator includes a plurality of second parallel arm SAW resonators connected in series with each other.

19. The antenna duplexer of claim 18 ,

wherein said first SAW filter further includes a third parallel arm SAW resonator, and

wherein said first parallel arm SAW resonator is connected closer to said antenna terminal than said third parallel arm SAW resonator.

20. The antenna duplexer of claim 19 , wherein a SAW resonator having a smallest capacitance of said second parallel arm SAW resonators has a larger capacitance than said third parallel arm SAW resonator.

21. The antenna duplexer of claim 13 , wherein said reception filter includes a second SAW filter including a third series arm SAW resonator disposed at an outermost arm towards said input terminal.

22. The antenna duplexer of claim 21 , wherein said third series arm SAW resonator includes a plurality of fourth series arm SAW resonators connected in series with each other.

23. The antenna duplexer of claim 22 ,

wherein said second SAW filter further includes a fifth series arm SAW resonator; and

wherein a SAW resonator having a smallest capacitance of said fourth series arm SAW resonators has a larger capacitance than said fifth series arm SAW resonator.

24. The antenna duplexer of claim 21 , wherein said second SAW filter further includes a first parallel arm SAW resonator including a plurality of second parallel arm SAW resonators connected in series with each other.

25. The antenna duplexer of claim 24 ,

wherein said second SAW filter further includes a third parallel arm SAW resonator, and

wherein said first parallel arm SAW resonator is disposed closer to said antenna terminal than said third parallel arm SAW resonator.

26. The antenna duplexer of claim 13 , wherein said transmission filter has a power durability at said output port thereof, the power durability being equal to or larger than a power durability at said input port thereof.