Dielectric filter, dielectric duplexer, and communication device

• US 6,774,744 B1
• Filed: 02/24/2000
• Issued: 08/10/2004
• Est. Priority Date: 02/25/1999
• Status: Expired due to Term

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Kubo, Hiroyuki, Kubota, Kazuhiko, Hattori, Jun
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): Nguyen, Patricia T.
• Application Number:
  US09/512,859
• Time in Patent Office: 1,629 Days
• Field of Search: 330/202, 330/219.1, 330/134
• US Class Current: 333/134
• CPC Class Codes: H01P 1/2086 multimode

Abstract

A dielectric filter that has attenuation poles on both the low frequency side and the high frequency side of its pass band, without using two dielectric resonators. The dielectric filter includes a cavity in which a conductive layer is formed, and a cross-shaped dielectric resonator disposed within the cavity, the dielectric resonator having at least three resonant modes, and coupling loops being coupled to the dielectric resonator. A coupling loop couples to a resonant mode at a first stage, among the resonant modes of the dielectric resonator, and also couples to resonant mode at a third stage in approximately negative-phase with respect to the first stage.

Claims

1. A dielectric filter, comprising:

a dielectric resonator having at least three resonant modes, including a conductive cavity, and a dielectric resonator arranged within said cavity; and

an input/output coupling that couples to said dielectric resonator,

wherein said input/output coupling couples to a resonant mode at a first stage, as well as to at least one resonant mode at an h-th stage (h=2n+1;

where n is an integer) approximately in negative-phase with respect to the first stage, among the resonant modes of said dielectric resonator.

2. The dielectric filter as claimed in claim 1, wherein said input/output coupling is a conductive loop, and wherein said input/output coupling is arranged in a direction such that it is coupled approximately in negative-phase with respect to a resonant mode to which said input/output coupling couples.

3. A dielectric filter, comprising:

a dielectric resonator having at least three resonant modes, including a conductive cavity, and a dielectric resonator arranged within said cavity; and

an input/output coupling that couples to said dielectric resonator,

wherein said input/output coupling couples to a resonant mode at a last stage, as well as to at least one resonant mode at a (k−

2n)-th stage (where n is an integer), the last stage being the k-th stage, approximately in negative-phase with respect to the last stage, among the resonant modes of said dielectric resonator.

4. The dielectric filter as claimed in claim 3, wherein said input/output coupling is a conductive loop, and wherein said input/output coupling is arranged in a direction such that it is coupled approximately in negative-phase with respect to a resonant mode to which said input/output coupling couples.

5. A dielectric duplexer, comprising:

two dielectric filters;

an input/output coupling connected to each of said dielectric filters, respectively; and

an antenna coupling commonly connected to said two dielectric filters,

wherein at least one of said dielectric filters is a dielectric filter comprising;

a dielectric resonator having at least three resonant modes, including a conductive cavity, and a dielectric resonator arranged within said cavity; and

an input/output coupling that couples to said dielectric resonator,

wherein said input/output coupling couples to a resonant mode at a first stage, as well as to at least one resonant mode at an h-th stage (h=2n+1;

where n is an integer) approximately in negative-phase with respect to the first stage, among the resonant modes of said dielectric resonator.

6. The dielectric filter as claimed in claim 5, wherein said input/output coupling is a conductive loop, and wherein said input/output coupling is arranged in a direction such that it is coupled approximately in negative-phase with respect to a resonant mode to which said input/output coupling couples.

7. A dielectric duplexer, comprising:

two dielectric filters;

an input/output coupling connected to each of said dielectric filters, respectively; and

an antenna coupling commonly connected to said dielectric filters,

wherein at least one of said dielectric filters is a dielectric filter comprising;

dielectric resonator having at least three resonant modes, including a conductive cavity, and a dielectric resonator arranged within said cavity; and

an input/output coupling that couples to said dielectric resonator,

wherein said input/output coupling couples to a resonant mode at a last stage, as well as to at least one resonant mode at a (k−

2n)-th stage (where n is an integer), the last stage being the k-th stage, approximately in negative-phase with respect to the last stage, among the resonant modes of said dielectric resonator.

8. The dielectric filter as claimed in claim 7, wherein said input/output coupling is a conductive loop, and wherein said input/output coupling is arranged in a direction such that it is coupled approximately in negative-phase with respect to a resonant mode to which said input/output coupling couples.

9. A communication device, comprising:

a dielectric duplexer;

a transmitting circuit that is connected to at least one of the input/output couplings of said dielectric duplexer;

a receiving circuit that is connected to the other one of the input/output couplings of said dielectric duplexer;

wherein said dielectric duplexer comprises;

two dielectric filters;

an input/output coupling connected to each of said dielectric filters, respectively; and

an antenna coupling commonly connected to said two dielectric filters,

wherein at least one of said dielectric filters is a dielectric filter comprising;

a dielectric resonator having at least three resonant modes, including a conductive cavity, and a dielectric resonator arranged within said cavity; and

an input/output coupling that couples to said dielectric resonator,

wherein said input/output coupling couples to a resonant mode at a first stage, as well as to at least one resonant mode at an h-th stage (h=2n+1;

where n is an integer) approximately in negative-phase with respect to the first stage, among the resonant modes of said dielectric resonator.

10. The communication device as claimed in claim 9, wherein said input/output coupling is a conductive loop, and wherein said input/output coupling is arranged in a direction such that it is coupled approximately in negative-phase with respect to a resonant mode to which said input/output coupling couples.

13. The communication device as claimed in claim 9, further comprising an antenna connected to said antenna coupling.

11. A communication device, comprising:

a dielectric duplexer;

a transmitting circuit that is connected to at least one of the input/output couplings of said dielectric duplexer;

a receiving circuit that is connected to the other one of the input/output couplings of said dielectric duplexer;

wherein said dielectric duplexer comprises;

two dielectric filters;

an input/output coupling connected to each of said dielectric filters, respectively; and

an antenna coupling commonly connected to said two dielectric filters,

wherein at least one of the dielectric filters is a dielectric filter comprising;

a dielectric resonator having at least three resonant modes, as including a conductive cavity, and a dielectric resonator arranged within said cavity; and

an input/output coupling that couples to said dielectric resonator,

wherein said input/output coupling couples to a resonant mode at a last stage, as well as to at least one resonant mode at a (k−

2n)-th stage (where n is an integer), the last stage being the k-th stage, approximately in negative-phase with respect to the last stage, among the resonant modes of said dielectric resonator.

12. The dielectric filter as claimed in claim 11, wherein said input/output coupling is a conductive loop, and wherein said input/output coupling is arranged in a direction such that it is coupled approximately in negative-phase with respect to a resonant mode to which said input/output coupling couples.

14. The communication device as claimed in claim 11, further comprising an antenna connected to said antenna coupling.