Tunable electronic circuit which converts balanced signals to unbalanced signals

Patent metadata

Field	Value
Publication number	US-9634639-B2
Application number	US-201514849749-A
Country	US
Kind code	B2
Filing date	Sep 10, 2015
Priority date	Sep 10, 2015
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

Balun with tunable bandpass filter characteristic includes first, second and third coupling elements disposed on a substrate. The first and second coupling elements are arranged on the substrate relative to the third coupling element to couple two identical but out of phase signals to form a corresponding unbalanced signal in the third coupling element. A plurality of tunable resonator elements are distributed within an area of the substrate defined on one side by the first and second coupling elements and on an opposing side by the third coupling element. The tunable resonator elements are configured to selectively produce a bandpass filter response.

First claim

We claim:

1. A tunable electronic circuit, comprising:
a substrate formed of a dielectric material;
a balanced signal transmission structure includes first and second coupling elements which are disposed on a first major surface of the substrate, each symmetrically connected at one end to a signal ground defined by a ground plane disposed on an opposing second major surface of the substrate;
an unbalanced signal transmission structure including a third coupling element disposed on the first major surface of the substrate and having one terminal end connected to the signal ground;
the first and second coupling elements arranged on the substrate relative to the third coupling element to couple two identical but out of phase signals from the balanced signal transmission structure to the unbalanced signal transmission structure and thereby form a corresponding unbalanced signal in the third coupling element;
a plurality of resonator elements distributed within an area of the substrate defined on one side by the first and second coupling elements and on an opposing side by the third coupling element, the plurality of resonator elements disposed on the first major surface of the substrate so as to be spaced apart from each other and from each of the first, second and third coupling elements;
wherein the plurality of resonator elements are cooperatively configured to produce a bandpass filter response when signals are communicated between the balanced signal transmission structure and the unbalanced signal transmission structure.

2. A tunable electronic circuit, comprising:
a substrate formed of a dielectric material;
a balanced signal transmission structure includes first and second coupling elements which are disposed on the substrate, each symmetrically connected at one end to a signal ground defined by a ground plane disposed on an opposing surface of the substrate;
an unbalanced signal transmission structure including a third coupling element disposed on the substrate and having one terminal end connected to the signal ground;
the first and second coupling elements arranged on the substrate relative to the third coupling element to couple two identical but out of phase signals from the balanced signal transmission structure to the unbalanced signal transmission structure and thereby form a corresponding unbalanced signal in the third coupling element; and
a plurality of resonator elements distributed within an area of the substrate defined on one side by the first and second coupling elements and on an opposing side by the third coupling element, the plurality of resonator elements spaced apart from each other and from each of the first, second and third coupling elements;
wherein the plurality of resonator elements are cooperatively configured to produce a bandpass filter response when signals are communicated between the balanced signal transmission structure and the unbalanced signal transmission structure;
wherein each of the first, second and third coupling elements and each of the plurality of resonator elements is respectively comprised of an elongated conductive planar strip disposed on a first major surface of the substrate, and the ground plane is disposed on an opposing major surface of the substrate.

3. The tunable electronic circuit according to claim 2 , wherein the first and second coupling elements are linear elements that extend along a common centerline to adjoining ends.

4. The tunable electronic circuit according to claim 3 , wherein the third coupling element is a linear element that extends parallel to the common centerline spaced apart from the first and second coupling elements.

5. The tunable electronic circuit according to claim 4 , wherein the plurality of resonator elements are linear elements which extend along a direction parallel to the common centerline.

6. The tunable electronic circuit according to claim 5 , wherein the plurality of resonator elements each includes a first end connected to the signal ground.

7. The tunable electronic circuit according to claim 6 , further comprising a plurality of variable reactive filter tuning elements, each having a first terminal respectively connected to one of the plurality of resonator elements at a second end opposed from the first end, and having a second terminal connected to the signal ground.

8. The tunable electronic circuit according to claim 7 , wherein the plurality of reactive tuning elements are each connected to the radiating elements on a same side of the tunable electronic circuit.

9. The tunable electronic circuit according to claim 7 , wherein the plurality of variable reactive filter tuning elements each have a reactive value which facilitates the bandpass filter response at a chosen operating frequency.

10. The tunable electronic circuit according to claim 7 , wherein the plurality of variable reactive filter tuning elements are responsive to at least one control signal which determines a reactance setting of the variable reactive filter tuning elements.

11. The tunable electronic circuit according to claim 7 , further comprising an antenna disposed on the substrate having a balanced antenna feed which is directly electrically connected to the balanced signal transmission structure.

12. The tunable electronic circuit according to claim 11 , wherein the balanced signal transmission structure includes a first and second conductor strips disposed on the substrate and respectively electrically connected to the first and second coupling elements, at least the first conductor connected to a first antenna radiating element disposed on the substrate and at least the second conductor connected to a second antenna radiating element disposed on the substrate.

13. The tunable electronic circuit according to claim 12 , further comprising a first variable reactive antenna tuning element having a first terminal connected to the first antenna radiating element and a second variable reactive antenna tuning element having a first terminal connected to the second antenna radiating element, wherein a reactance variation of the first and second variable reactive antenna tuning elements causes a variation in a resonant frequency of the antenna.

14. The tunable electronic circuit according to claim 13 , wherein the first variable reactive antenna tuning element has a second terminal connected to the signal ground, and the second variable reactive antenna tuning element has a second terminal connected to the signal ground.

15. The tunable electronic circuit according to claim 13 , wherein the first and second variable reactive antenna tuning elements are connected at a terminal end of each of said first and second radiating elements which is distal from a feed end respectively connected to the first and second differential conductor.

16. The tunable electronic circuit according to claim 12 , wherein the plurality of variable reactive filter tuning elements, the first variable reactive antenna tuning element, and the second variable reactive antenna tuning element are each responsive to at least one control signal which selectively controls a resonant frequency of the antenna in conjunction with a center frequency of the bandpass filter.

17. The tunable electronic circuit according to claim 16 , further comprising a control system responsive to at least one input defining a communication condition, wherein the control signal is produced by the control system.

18. A tunable electronic circuit according to claim 1 , wherein the bandpass filter response is defined by at least three poles which co

Assignees

• Harris Corp

Inventors

• Ramirez Daniel A
• Hash Ronald J

Classifications

• H03H7/0161

  Bandpass filters (H03H7/12 takes precedence) · CPC title

• H01Q1/50

  Structural association of antennas with earthing switches, lead-in devices or lightning protectors · CPC title

• H03H9/2431

  Ring resonators · CPC title

• H03H7/42 Primary

  Networks for transforming balanced signals into unbalanced signals and vice versa, e.g. baluns · CPC title

• H01Q9/16

  with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole (H01Q9/44 takes precedence) · CPC title