Electronically tunable RF diplexers tuned by tunable capacitors
First Claim
1. A diplexer comprising:
- a first tunable bandpass filter including a first tunable capacitor and connected to a first port;
a second tunable bandpass filter including a second tunable capacitor and connected to a second port; and
means for coupling the first bandpass filter and the second bandpass filter to a third port, wherein the means for coupling the first bandpass filter and the second bandpass filter to a third port comprises one of;
a circulator, a T-junction, and an orthomode transducer.
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Abstract
A diplexer includes a first tunable bandpass filter connected to a first port, a second tunable bandpass filter connected to a second port, and a coupling element for coupling the first bandpass filter and the second bandpass filter to a third port. Each of the tunable bandpass filters includes a tunable capacitor, wherein a control signal applied to the tunable capacitor controls the transmission characteristic of the filter. The tunable capacitor can be a tunable dielectric varactor or a microelectromechanical variable capacitor. The coupling element can include one of: a circulator, a T-junction, and an orthomode transducer. Each of the first and second filters can comprise a fin line filter including a plurality of tunable dielectric capacitors mounted within a waveguide for controlling the filter transmission characteristics. Fixed bandpass filters can be inserted between each of the tunable bandpass filters and the coupling element.
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Citations
18 Claims
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1. A diplexer comprising:
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a first tunable bandpass filter including a first tunable capacitor and connected to a first port;
a second tunable bandpass filter including a second tunable capacitor and connected to a second port; and
means for coupling the first bandpass filter and the second bandpass filter to a third port, wherein the means for coupling the first bandpass filter and the second bandpass filter to a third port comprises one of;
a circulator, a T-junction, and an orthomode transducer. - View Dependent Claims (2, 3)
a tunable dielectric varactor.
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3. A diplexer according to claim 1, wherein the first and second tunable capacitors each comprise:
a microelectromechanical variable capacitor.
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4. A diplexer comprising:
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a first tunable bandpass filter including a first tunable capacitor and connected to a first port;
a second tunable bandpass filter including a second tunable capacitor and connected to a second port; and
means for coupling the first bandpass filter and the second bandpass filter to a third port, wherein;
the first tunable bandpass filter comprises a first plurality of resonators, wherein the first tunable capacitor couples a signal between two of the resonators in the first plurality of resonators; and
the second tunable bandpass filter comprises a second plurality of resonators, wherein the second tunable capacitor couples a signal between two of the resonators in the second plurality of resonators.
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5. A diplexer comprising:
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a first tunable bandpass filter including a first tunable capacitor and connected to a first port;
a second tunable bandpass filter including a second tunable capacitor and connected to a second port; and
means for coupling the first bandpass filter and the second bandpass filter to a third port, wherein the first tunable bandpass filter comprises;
a first waveguide; and
a first septum position along an axis of the first waveguide; and
wherein the first tunable capacitor is mounted on the septum. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
a substrate having a first dielectric constant and having generally a planar surface;
a tunable dielectric layer positioned on the generally planar surface of the substrate, the tunable dielectric layer having a second dielectric constant greater than said first dielectric constant; and
first and second electrodes positioned on a surface of the tunable dielectric layer opposite the generally planar surface of the substrate, said first and second electrodes being separated to form a gap therebetween.
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7. A diplexer according to claim 6, wherein the first tunable capacitor further comprises:
an insulating material in said gap.
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8. A diplexer according to claim 6, wherein the tunable dielectric layer in the first tunable dielectric varactor has a permittivity in a range from about 20 to about 2000, and a tunability in a range from about 10% to about 80% at a bias voltage of about 10 V/μ
- m.
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9. A diplexer according to claim 5, wherein the second tunable bandpass filter comprises:
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a second waveguide; and
a second septum position along an axis of the second waveguide; and
wherein the second tunable capacitor is mounted on the second septum.
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10. A diplexer according to claim 9, wherein the second tunable capacitor comprises:
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a substrate having a first dielectric constant and having generally a planar surface;
a tunable dielectric layer positioned on the generally planar surface of the substrate, the tunable dielectric layer having a second dielectric constant greater than said first dielectric constant; and
first and second electrodes positioned on a surface of the tunable dielectric layer opposite the generally planar surface of the substrate, said first and second electrodes being separated to form a gap therebetween.
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11. A diplexer according to claim 10, wherein the second tunable capacitor further comprises:
an insulating material in said gap.
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12. A diplexer according to claim 9, wherein the tunable dielectric layer in the second tunable capacitor has a permittivity in a range from about 20 to about 2000, and a tunability in a range from about 10% to about 80% at a bias voltage of about 10 V/μ
- m.
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13. A diplexer according to claim 10, further comprising:
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a first fixed bandpass filter connected between the first tunable bandpass and the means for coupling the first bandpass filter and the second bandpass filter to a third port; and
a second fixed bandpass filter connected between the second tunable bandpass and the means for coupling the first bandpass filter and the second bandpass filter to a third port.
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14. A diplexer according to claim 13, wherein:
each of the first and second fixed bandpass filters has a larger passband than each of the first and second tunable filters.
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15. A diplexer according to claim 13, wherein:
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the first tunable filter has a passband that can be tuned within a passband of the first fixed bandpass filter; and
the second tunable filter has a passband that can be tuned within a passband of the second fixed bandpass filter.
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16. A diplexer comprising:
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a first tunable bandpass filter including a first tunable capacitor and connected to a first port;
a second tunable bandpass filter including a second tunable capacitor and connected to a second port; and
means for coupling the first bandpass filter and the second bandpass filter to a third port, wherein;
the first tunable bandpass filter comprises a first plurality of resonators, wherein the first tunable capacitor is positioned within one of the resonators in the first plurality of resonators; and
the second tunable bandpass filter comprises a second plurality of resonators, wherein the second tunable capacitor is positioned within one of the resonators in the second plurality of resonators. - View Dependent Claims (17, 18)
a tunable dielectric varactor.
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Specification