Flat radio frequency transmission line

Patent metadata

Field	Value
Publication number	US-10224591-B2
Application number	US-201715704942-A
Country	US
Kind code	B2
Filing date	Sep 14, 2017
Priority date	Sep 16, 2016
Publication date	Mar 5, 2019
Grant date	Mar 5, 2019

Abstract

A radio frequency (RF) transmission line includes a first conductive layer, a second conductive layer conductively isolated from the first conductive layer, a center conductor disposed between the first conductive layer and the second conductive layer, dielectric material disposed between the first conducive layer and the second conductive layer and at least partially surrounding the center conductor, and an RF choke element that conducts a direct current signal between the center conductor and the second conductive layer.

First claim

What is claimed is:

1. A radio frequency (RF) transmission line comprising:
a first conductive layer;
a second conductive layer conductively isolated from the first conductive layer;
a center conductor disposed between the first conductive layer and the second conductive layer;
dielectric material disposed between the first conducive layer and the second conductive layer and at least partially surrounding the center conductor; and
an RF choke element that conducts a direct current signal between the center conductor and the second conductive layer.

2. The RF transmission line of claim 1 , wherein the RF choke element comprises an inductor having a first end conductively coupled with the second conductive layer and a second end conductively coupled to the center conductor.

3. The RF transmission line of claim 1 , wherein the RF transmission line has a characteristic impedance defined by the first conductive layer, the second conductive layer, the center conductor and the dielectric material.

4. The RF transmission line of claim 1 , wherein the RF transmission line is a transverse-electromagnetic mode (TEM) line.

5. The RF transmission line of claim 1 , further comprising a connector structure at a first distal end of the RF transmission line, wherein:
the connector structure comprises a ground reference structure that is conductively coupled to the first conductive layer;
the second conductive layer is conductively coupled to the center conductor; and
the connector structure is a coaxial connector that comprises a center pin that is conductively coupled to the center conductor and the RF choke element at a node.

6. The RF transmission line of claim 5 , wherein:
the first conductive layer lies in a first plane;
the second conductive layer lies in a second plane that is parallel to the first plane; and
the center conductor lies at least partially in a third plane that is parallel to, and positioned vertically between, the first plane and the second plane.

7. The RF transmission line of claim 6 , wherein:
the node lies in the second plane; and
the center conductor is conductively coupled to the node by a via that passes at least partially through the dielectric material.

8. The RF transmission line of claim 1 , wherein:
the RF choke element comprises an inductor;
the inductor is disposed at least partially above a top surface of the RF transmission line; and
the second conductive layer has an opening therein at least partially below the inductor.

9. The RF transmission line of claim 8 , wherein the center conductor is routed around the opening such that the opening does not vertically overlap the center conductor.

10. The RF transmission line of claim 1 , further comprising a blocking capacitor coupled between the center conductor and one end of the RF choke element.

11. The RF transmission line of claim 1 , wherein a cross-section of the RF transmission line at a midpoint along a longitudinal dimension of the RF transmission line has a thickness in a vertical dimension of the RF transmission line that is less than 3 mm.

12. The RF transmission line of claim 1 , wherein the first conductive layer is separated from the second conductive layer by a constant distance along a length of the center conductor.

13. The RF transmission line of claim 1 , further comprising an RF shielding structure that at least partially covers the RF choke element.

14. The RF transmission line of claim 13 , wherein the RF shielding structure comprises a conductive lip configured to capacitively couple to one of the first conductive layer and the second conductive layer.

15. The RF transmission line of claim 14 , wherein the RF shielding structure further comprises a second conductive lip configured to capacitively couple to another of the first conductive layer and the second conductive layer.

16. The RF transmission line of claim 1 , wherein the second conductive layer has a first resistance, and the center conductor has a second resistance greater than the first resistance.

17. The RF transmission line of claim 1 , wherein the second conductive layer has a first current capacity, and the center conductor has a second current capacity that is less than the first current capacity.

18. A data communication system comprising:
an indoor signal processing unit comprising a first coaxial cable including a first central conductor and a first ground structure, the indoor signal processing unit configured to communicate a multiplexed signal comprising an RF component and a direct current (DC) component via the first coaxial cable;
an outdoor signal processing unit comprising a second coaxial cable including a second central conductor and a second ground structure, the outdoor signal processing unit configured to communicate the multiplexed signal via the second coaxial cable; and
a flat transmission line connected at a first end to the first coaxial cable and at a second end to the second coaxial cable, the flat transmission line comprising:
a first conductive layer conductively coupled to the first ground structure and the second ground structure;
a second conductive layer physically isolated from the first conductive layer;
a center conductor disposed between the first conductive layer and the second conductive layer, the center conductor being coupled to the first central conductor and the second central conductor to carry the RF component;
a first radio frequency (RF) choke element conductively coupled to a first end of the center conductor and to a first end of the second conductive layer; and
a second RF choke element conductively coupled to a second end of the center conductor and to a second end of the second conductive layer, wherein the first and second RF choke elements are configured to conduct at least a portion of the DC component of the multiplexed signal between the center conductor and the second conductive layer.

19. The data communication system of claim 18 , wherein the flat transmission line is configured to be installed between a window pane and a frame of a window installment.

20. The data communication system of claim 18 , wherein the outdoor signal processing unit is coupled to an antenna configured to wirelessly communicate the RF component of the multiplexed signal.

21. The data communication system of claim 18 , wherein the center conductor is coupled to the first central conductor and the second central conductor to carry a portion of the DC component.

22. A method of manufacturing a radio frequency (RF) cable, the method comprising:
disposing first and second conductive layers on a substrate, the substrate conductively isolating the first conductive layer from the second conductive layer;
forming a center conductor between the first conductive layer and the second conductive layer in the substrate; and
conductively coupling an RF choke element between the center conductor and the second conductive layer, the RF choke element being configured to conduct a direct current signal between the center conductor and the second conductive layer.

23. The method of claim 22 , wherein the RF choke element comprises an inductor connected in series with the second conductive layer.

24. The method of claim 22 , further comprising conductively coupling a signal transmission pin of a coaxial cable connector to the center conductor and the RF choke element at a node.

25. The method of claim 24 , further co

Assignees

• Viasat Inc

Inventors

• Petrovic Branislav A

Classifications

• H01P3/085

  Triplate lines · CPC title

• H01R24/42

  comprising impedance matching means or electrical components, e.g. filters or switches · CPC title

• H01P1/30

  for compensation of, or protection against, temperature or moisture effects {; for improving power handling capability (H01P1/04, H01P1/08 take precedence)} · CPC title

• H01R13/623

  Casing or ring with helicoidal groove · CPC title

• H01P5/085 Primary

  Coaxial-line/strip-line transitions · CPC title