Filter device and branching filter using same

• US 20050030126A1
• Filed: 07/30/2004
• Published: 02/10/2005
• Est. Priority Date: 08/04/2003
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: TDK Corporation
• Inventors: Inoue, Kenji, Saitou, Hisatoshi
• Granted Patent: US 7,212,083 B2
• Time in Patent Office: Days
• US Class Current: 333/133
• CPC Class Codes: H03H 9/583 comprising a plurality of piezoelectric layers acoustically coupled
• CPC Class Codes: H03H 9/60 Electric coupling means therefor H03H9/0095 takes precedence
• CPC Class Codes: H03H 9/605 consisting of a ladder configuration

Abstract

A filter device is provided which is low in power loss, small in size and operates in wide bands. The filter device includes a first signal-side resonator having an input signal electrode, an output signal electrode, a first piezoelectric film, an input electrode film, and a common electrode film being commonly used by a second signal-side resonator and sandwiching the first piezoelectric film using the input electrode film, a second signal-side resonator having a second piezoelectric film formed in layers on the first piezoelectric film, an output electrode film, a common electrode film sandwiching the second piezoelectric film using the output electrode film and being acoustically coupled to the first signal resonator, and a ground-side resonator connected between the common electrode film and a ground electrode and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to resonant frequencies in which the first and second signal-side resonators operate.

Claims

1. A filter device comprising:

at least one signal-side resonator that operates in a specified resonant frequency; and

at least one ground-side resonator that operates in an anti-resonant frequency abnormal conforming to said resonant frequency in which said signal-side resonator operates;

wherein said signal-side resonator and said ground-side resonator are acoustically coupled partially or totally to each other.

26. The filter device according to claim 1, wherein a dielectric layer or an acoustic reflecting layer is formed between said common electrode films.

27. The filter device according to claim 1, wherein an inductor element is connected between said common electrode film and said ground electrode or between said non-common electrode and said ground electrode.

28. The filter device according to claim 1, wherein an inductor element is connected to at least either of said input signal electrode or said output signal electrode.

29. The filter device according to claim 1, wherein a film thickness of a piezoelectric film containing said signal-side resonator is smaller than that of a piezoelectric film not containing said signal-side resonator.

30. The filter device according to claim 1, wherein said filter device is constructed of an SMR (Solid Mounted Resonator)-type piezo-resonator or a diaphram-type piezo-resonator.

31. A branching filter using two or more filter devices stated in claim 1.

2. A filter device comprising:

an input signal electrode and an output signal electrode;

at least one signal-side resonator being connected between said input signal electrode and said output signal electrode and operating in a specified resonant frequency; and

at least one ground-side resonator being formed between a signal path connecting said input signal electrode to said output signal electrode and a ground electrode and operating in an anti-resonant frequency almost conforming to said resonant frequency in which said signal-side resonator operates;

wherein said signal-side resonator and said ground-side resonator are acoustically coupled partially and totally to each other.

3. A filter device comprising:

a first signal-side resonator and a second signal-side resonator both operating in resonant frequencies almost conforming to one another and both being acoustically coupled to each other and both having a layer-stacked structure;

a ground-side resonator being connected to a common electrode film being commonly used by said first signal-side resonator and said second signal-side resonator or to a non-common electrode film being not commonly used by said first signal-side resonator and said second signal-side resonator, and operating in an anti-resonant frequency almost conforming to said resonant frequencies in which said first and second signal-side resonators operate.

4. A filter device comprising:

a first signal-side resonator and a second signal-side resonator both operating in resonant frequencies almost conforming to one another and both being acoustically coupled to each other; and

a ground-side resonator being connected to at least one common electrode film being commonly used by said first signal-side resonator and said second signal-side resonator or to at least one non-common electrode film being not commonly used by said first signal-side resonator and said second signal-side resonator, and operating in an anti-resonant frequency almost conforming to said resonant frequencies in which said first and second signal-side resonators operates;

wherein said common electrode film and said non-common electrode film to which said ground-side resonator is not connected are not connected to a ground electrode.

5. A filter device comprising:

an input signal electrode and an output signal electrode;

a first signal-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and a common electrode film being commonly used by other signal-side resonator and sandwiching said first piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a second signal-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, an output electrode film being connected to said output signal electrode, and a common electrode film being commonly used by other signal-side resonator and sandwiching said, second piezoelectric film using said output electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency and being acoustically connected to said first signal-side resonator; and

a ground-side resonator being connected between said common electrode film and ground electrode and operating in a specified resonant frequency and in an anti-resonant frequency almost to resonant frequencies in which said first signal-side resonator and said second signal-side resonator operate.

6. The filter device according to claim 5, wherein at least one third signal-side resonator having a third piezoelectric film formed between said first piezoelectric film and said second piezoelectric film and having two common electrode films being commonly used by other signal-side resonator and sandwiching said third piezoelectric film, and operating in a specified resonant frequency and in a specified anti-resonant frequency and being acoustically coupled to said first signal-side resonator and to said second signal-side resonator is formed between said first signal-side resonator and said second signal-side resonator.

7. A filter device comprising:

an input signal electrode and an output signal electrode;

a first signal-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and a common electrode film being commonly used by other signal-side resonator and sandwiching said first piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a second signal-side resonator having said first piezoelectric film, an output electrode film connected to said, output signal electrode, and a common electrode film being commonly used by other signal-side resonator and sandwiching said first piezoelectric film using said output electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a third signal-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, a common electrode film being commonly used by other signal-side resonator, and an intermediate electrode film sandwiching said second, piezoelectric film using said common electrode film and operating in a specified resonant frequency and in a specified anti-resonant frequency and being acoustically coupled to said first signal-side resonator;

a fourth signal-side resonator having said second piezoelectric film, a common electrode film being commonly used by other signal-side resonator, and an intermediate electrode film connected to the intermediate electrode film in said third signal-side resonator and sandwiching said second piezoelectric film using said common electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency and being acoustically coupled to said second signal-side resonator; and

a ground-side resonator being formed between said common electrode film and a ground electrode and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to resonant frequencies in which said first signal-side resonator, said second signal-side resonator, said third signal-side resonator, and said fourth signal-side resonator operate.

8. A filter device comprising,

first and second ground-side resonators operating in anti-resonant frequencies almost conforming to one another and being acoustically coupled to each other and connecting a common electrode film being commonly used by said first and second ground-side resonators to a ground electrode and having a layer-stacked structure;

and

a signal-side resonator formed between a non-common electrode film in said first ground-side resonator and a non-common electrode film in said second ground-side resonator and operating in resonant frequencies almost conforming to anti-resonant frequencies in which said first and second ground-side resonators operate.

9. The filter device according to claim 8, wherein said signal-side resonator contains a common electrode film formed on a same layer as said first ground-side resonator or said second ground-side resonator are formed.

10. The filter device according to claim 9, wherein said signal-side resonator is a piezoelectric thin-film resonator, surface acoustic wave resonator, or dielectric resonator.

11. A filter device comprising:

an input signal electrode and an output signal electrode;

a signal-side resonator being connected between said input signal electrode and said output signal electrode and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a first ground-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and a common electrode film connected to said input signal electrode, and a common electrode film being commonly used by other ground-side resonator and sandwiching said first piezoelectric film using said input electrode film and being connected to a ground electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operate;

a second ground-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, an output electrode film connected to said output signal electrode, and a common electrode film being commonly used by other ground-side resonator and sandwiching said second piezoelectric film using said output electrode film and being connected to said ground electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates and being acoustically coupled to said first ground-side resonator.

12. A filter device comprising:

an input signal electrode and an output signal electrode;

a signal-side resonator being connected between said input signal electrode and said output signal electrode and operating in a specified resonant frequency, and in a specified anti-resonant frequency;

a first ground-side resonator having a first piezoelectric film, a first ground-electrode film connected to a ground electrode, and a common electrode film being commonly used by other ground-side resonator and sandwiching the first piezoelectric film using said first ground electrode film and being formed between said input signal electrode and said output signal electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operate; and

a second ground-side resonator having a second piezoelectric film formed on the first piezoelectric film in a layer-stacking direction, a second ground electrode film connected to said ground electrode and a common electrode film being commonly used by other ground-side resonator and sandwiching said second piezoelectric film using said second ground electrode film and being formed between said input signal electrode and said output signal electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator rotates and being acoustically coupled to said first ground-side resonator.

13. A filter device comprising:

an input signal electrode and an output signal electrode;

a signal-side resonator being connected between said input signal electrode and said output signal electrode and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a first ground-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and a common electrode film being commonly used by other ground-side resonator and being connected to a ground electrode and sandwiching said first piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates,

a second ground-side resonator having said first piezoelectric film, an output electrode film being connected to said output signal electrode, and a common electrode film being commonly used by other ground-side resonator and being connected to said ground electrode and sandwiching said first piezoelectric film using said output electrode film, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates,

a third ground-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, a common electrode film being commonly used by other ground-side resonator, and an intermediate electrode film sandwiching said second piezoelectric film using said common electrode film, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal side resonator operates; and

a fourth ground-side resonator having said second piezoelectric film, a common electrode film being commonly used by other ground-side resonator, and an intermediate electrode film being connected to said intermediate electrode film in said third ground-side resonator and sandwiching said second piezoelectric film using said common electrode film, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates.

14. A filter device comprising:

an input signal electrode and an output signal electrode;

a signal-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and an output electrode film connected to said output signal electrode and sandwiching said first piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency, and

a ground-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction and a ground electrode film being connected to a ground electrode and sandwiching said second piezoelectric film using said output electrode film, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates and being acoustically coupled to said signal-side resonator.

15. A filter device comprising,

an input signal electrode and an output signal electrode;

a ground-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and a ground electrode film being connected to a ground electrode and sandwiching said first piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in an anti-resonant frequency; and

a signal-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, said input electrode film and an output electrode film being connected to said output electrode film and sandwiching said second piezoelectric film using said input electrode film, and operating in a resonant frequency almost conforming to an anti-resonant frequency in which said ground-side resonator operates and in a specified anti-resonant frequency and being acoustically coupled to said ground-side resonator.

16. A filter device comprising:

an input signal electrode and an output signal electrode;

a signal-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and an output electrode film being connected to said output signal electrode and sandwiching said first piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a first ground-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction and a first ground electrode film being connected to a ground electrode and sandwiching said second piezoelectric film using said output electrode film and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates and being acoustically coupled to said signal-side resonator; and

a second ground-side resonator having a third piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, a ground electrode film being connected to a ground electrode and sandwiching said third piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates and being acoustically coupled to said signal-side resonator

17. A filter device comprising:

an input signal electrode and an output signal electrode;

a first signal-side resonator having a first piezoelectric film, on input electrode film connected to said input signal electrode and a common electrode film being commonly used by a first ground-side resonator and sandwiching said first piezoelectric film, using said input electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a second signal resonator having a first piezoelectric film, an output electrode film connected to said output signal electrode, and a common electrode film being commonly used by a second ground-side resonator and sandwiching said first piezoelectric film using said output electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a first ground-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction and a first ground electrode film being connected to a ground electrode and sandwiching said second piezoelectric film using said common electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates and being acoustically coupled to said first signal-side resonator, and

a second ground-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction and a second ground electrode film being connected to a ground electrode and sandwiching said second piezoelectric film using said common electrode film, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates and being acoustically coupled to said second signal-side resonator.

18. The filter device according to claim 17, wherein at least one signal-side resonator is formed between two said common electrodes.

19. A filter device comprising:

an input signal electrode and an output signal electrode;

a first signal-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and a common electrode film being commonly used by other signal-side resonator and sandwiching said first piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a second signal-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, an output electrode film connected to said output signal electrode, and a common electrode film being commonly used by other signal-side resonator and sandwiching said second piezoelectric film using said output electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency and being acoustically coupled to said first signal-side resonator;

a first ground-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode and a common electrode film being commonly used by other ground-side resonator and sandwiching said first piezoelectric film using said input electrode film, and being connected to a ground electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates; and

a second ground-side resonator having said second piezoelectric layer, an intermediate electrode film being connected to said common electrode film in said signal-side resonator, and a common electrode film being commonly used by other ground-side resonator and sandwiching said second piezoelectric film using said intermediate electrode film and being connected to said ground electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator and being acoustically coupled to said first ground-side resonator.

20. A filter device comprising:

an input signal electrode and an output signal electrode;

a first signal-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and a common electrode film being commonly used by other signal-side resonator and sandwiching said first piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in an anti-resonant frequency;

a second signal-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, an intermediate electrode film connected to other intermediate electrode film, and a common electrode film being commonly used by other signal-side resonator and sandwiching said second piezoelectric film using said intermediate electrode film, and operating in a resonant frequency and in a specified anti-resonant frequency and being acoustically coupled to said first signal-side resonator;

and being acoustically coupled to said first signal-side resonator;

a third signal-side resonator having said first piezoelectric film, an output electrode film connected to said output signal electrode, and a common electrode film being commonly used by other signal-side resonator and sandwiching said first piezoelectric film using said output electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a fourth signal-side resonator having said second piezoelectric film, an intermediate electrode film connected to other intermediate electrode film, and a common electrode film being commonly used by other signal-side resonator and sandwiching said second piezoelectric film using said intermediate electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency and being acoustically coupled to said third signal-side resonator;

a first ground-side resonator having said first piezoelectric film, an intermediate electrode film connected to said common electrode film in said signal-side resonator, and a common electrode film being commonly used by other ground-side resonator and sandwiching said first piezoelectric film using said intermediate electrode film and being connected to a ground electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates; and

a second ground-side resonator having said second piezoelectric film, an intermediate electrode film connected to said common electrode film in said signal-side resonator, and a common electrode film being commonly used by other ground-side resonator and sandwiching said second piezoelectric film using said intermediate electrode film and being connected to said ground electrode, and operating in a specified resonant frequency and in a specified anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates and being acoustically coupled to said first ground-side resonator.

21. A filter device comprising:

an input signal electrode and an output signal electrode;

a first ground-side resonator having a first piezoelectric film, a first ground-side input electrode film connected to said input signal electrode, and a common electrode film being commonly used by other ground-side resonator and sandwiching said first piezoelectric using said first ground-side input electrode film and being connected to a ground electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates;

a second ground-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, a second ground-side input electrode film connected to said input signal electrode, and a common electrode film being commonly used by other ground-side resonator and sandwiching said second piezoelectric film using said second ground-side input electrode film and being connected to said ground electrode, and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates and being acoustically coupled to said first ground-side resonator;

a signal-side resonator having a first piezoelectric film, and a signal-side input electrode connected to said input signal electrode, and an output electrode film being connected to said output signal electrode and sandwiching said first piezoelectric film using said signal-side input electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency; and

a third ground-side resonator having said second piezoelectric film, a ground electrode film being connected to said ground electrode and sandwiching said second piezoelectric film using said output electrode film and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator operates.

22. A filter device comprising:

an input signal electrode and an output signal electrode;

a first signal-side resonator having a first piezoelectric film, an input electrode film connected to said input signal electrode, and a common electrode film being commonly used by other signal-side resonator and sandwiching said first piezoelectric film using said input electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency;

a second signal-side resonator having a second piezoelectric film formed on said first piezoelectric film in a layer-stacking direction, an intermediate electrode film connected to other common electrode film, and a common electrode film being commonly used by other signal-side resonator and sandwiching said second piezoelectric film using said intermediate electrode film, and operating in a specified resonant frequency and in a specified anti-resonant frequency and being acoustically coupled to said first signal-side resonator;

a third signal-side resonator having a first piezoelectric film, an output electrode film connected to said output signal electrode, a common electrode film being connected to said intermediate electrode film and sandwiching said first piezoelectric film using said output electrode film, and operating in a specified resonant frequency and in a specified anti-resonant

a ground-side resonator having said second piezoelectric film, a ground electrode film being connected to a ground electrode and sandwiching said second piezoelectric film using said common electrode film in said third signal-side resonator and operating in a specified resonant frequency and in an anti-resonant frequency almost conforming to a resonant frequency in which said signal-side resonator and being acoustically coupled to said third signal-side resonator.

23. A filter device comprising,

two or more ground-side resonators operating in anti-resonant frequencies almost conforming to one another and being acoustically coupled to one anther and having a non-common electrode film and connecting a common electrode film being commonly used by said two or more ground-side resonators to a ground electrode and having a layer-stacked structure;

and

two or more signal-side resonators operating in resonant frequencies almost conforming to an anti-resonant frequency in which said ground-resonator operates and being acoustically coupled to one another and wherein one non-common electrode film is connected to one non-common electrode in said ground-side resonator and another non-common electrode or the common electrode being commonly used by said two or more signal-side resonators is connected to another non-common electrode film in said ground-side resonator and being stacked in layers together with said ground-side resonators.

24. A filter device comprising:

two or more signal-side resonators operating in resonant frequencies almost conforming to one another and being acoustically coupled to one another and connecting a ground-side resonator one another and being acoustically coupled to one another and connecting a ground-side resonator to at least either of a common electrode film being commonly used by said two or more signal-side resonators or a non-common electrode film being not commonly used by them and having a layer-stacked structure.

25. A filter device comprising:

two or more ground-side resonators operating in anti-resonant frequencies almost conforming to one another and being acoustically coupled to one another and connecting a common electrode film being commonly used by said two or more ground-side resonators to a ground electrode, and having a layer-stacked structure.