Filter device utilizing stacked resonators and acoustic coupling and branching filter using same

1. 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.

2. The filter device according to claim 1 , 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.

3. The filter device according to claim 2 , wherein said signal-side resonator is a piezoelectric thin-film resonator, surface acoustic wave resonator, or dielectric resonator.

4. 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 another 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 another 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 another 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 another 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 and-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.

5. 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 another 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 another 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.

6. 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 another 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 witch 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 another 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 operates and being acoustically coupled to said first ground-side resonator.

7. 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 another 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 another 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 another 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 another 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.

8. 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,

wherein at least one signal-side resonator is formed between two said common electrodes.

9. 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 another 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 another 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 said first piezoelectric film, an input electrode film connected to said input signal electrode and a common electrode film being commonly used by another 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 film, 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 another 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.

10. 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 another 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 another intermediate electrode film, and a common electrode film being commonly used by another 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,

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 another 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 another intermediate electrode film, and a common electrode film being commonly used by another 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 another 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 another 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.

11. 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 another round-side resonator and sandwiching said first piezoelectric film 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 another 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 said 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.

12. 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 another 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 another common electrode film, and a common electrode film being commonly used by another 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 said 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 frequency; and

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 operates and being acoustically coupled to said third signal-side resonator.

13. A filter device comprising:

two or more ground-side resonators operating in and-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-side resonators operate 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.