Twisted-pair planar conductor line off-set structure

• US 5,430,247 A
• Filed: 08/31/1993
• Issued: 07/04/1995
• Est. Priority Date: 08/31/1993
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Bockelman, David E.
• Primary Examiner(s): Tolin, Gerald P.
• Assistant Examiner(s): TSO, LAURA K
• Application Number:
  US08/115,176
• Time in Patent Office: 672 Days
• Field of Search: 361/749, 361/777, 439/77, 174/250, 174/254, 174/261, 174/262, 174/268, 174/33, 174/34
• US Class Current: 174/33
• CPC Class Codes: H01L 2223/6627 Waveguides, e.g. microstrip line, strip line, coplanar line
• CPC Class Codes: H01L 23/528 Geometry or layout of the interconnection structure H01L27/0207 takes precedence; algorithms G06F30/00
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/1903 including wave guides
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01P 3/081 Microstriplines
• CPC Class Codes: H05K 1/0228 Compensation of cross-talk by a mutually correlated lay-out of printed circuit traces, e.g. for compensation of cross-talk in mounted connectors balanced signal pairs H05K1/0245
• CPC Class Codes: H05K 1/0245 Lay-out of balanced signal pairs, e.g. differential lines or twisted lines
• CPC Class Codes: H05K 2201/097 Alternating conductors, e.g. alternating different shaped pads, twisted pairs; Alternating components
• CPC Class Codes: H05K 2201/10689 Leaded Integrated Circuit [IC] package, e.g. dual-in-line [DIL]
• CPC Class Codes: H05K 9/0039 Galvanic coupling of ground layer on printed circuit board [PCB] to conductive casing printed shielding conductors, ground planes or power planes for reduction of cross-talk or noise in printed circuits H05K1/0218

Abstract

A twisted-pair conductor line structure is formed on a substrate (22) having insulated conductive layers (10, 11). The conductive layers are used to form first, second, third, and fourth conductive planar segments (16). A first conductive link (44) joins the first and second planar conductive segments to provide a first signal path. Similarly, a second conductive link (46) joins the third and fourth planar conductive segments to provide a second signal path. The first and second conductive links are operatively arranged to form a twist (17) in the first and second signal paths, such that the resulting magnetic fields (57, 59) around the twisted conductive segments will be opposite to each other for cancelling each other out, in order to reduce the magnetic field radiation to the surrounding environment. Two such twisted-pair conductor lines are placed such that their twisted portions are off-set from each other.

Claims

1. A differential transmission line system comprising:

a first planar differential twisted transmission line having a first twisted portion and a first successive untwisted portion for forming a virtual twisted pair without making an electrical connection;

a second planar differential twisted transmission line having a second twisted portion and a second successive untwisted portion for forming a virtual twisted pair without making an electrical connection wherein the first and second twisted portions are off-set from each other, each said planar differential twisted transmission line comprising;

insulated conductive layers;

first, second, third and fourth conductive planar segments formed from the conductive layers;

a first conductive link joining the first and second planar conductive segments to provide a first signal path;

a second conductive link joining the third and fourth planar conductive segments to provide a second signal path and the first and second conductive links operatively arranged to formed the twisted portion in the first and second signal paths;

said insulated conductive layers comprising first and second conductive layers, the second conductive layer disposed below the first conductive layer; and

wherein the first and second planar conductive segments and the first link formed from the first conductive layer, the third and fourth planar conductive segments and the second link are formed from the second conductive layer and the first and third planar conductive segments run parallel to each other, the fourth and second planar conductive segments run parallel to each other, the first and fourth planar conductive segments are substantially longitudinally aligned with each other, the third and second planar conductive segments are substantially longitudinally aligned with each other, and the second link crosses under the first link, each in opposed directions.

2. The system of claim 1 wherein each planar differential twisted transmission line comprises:

insulated conductive layers;

first, second, third, and fourth conductive planar segments formed from the conductive layers;

a first conductive link joining the first and second planar conductive segments to provide a first signal path;

a second conductive link joining the third and fourth planar conductive segments to provide a second signal path; and

the first and second conductive links operatively arranged to form the twisted portion in the first and second signal paths.

3. The system of claim 1 further comprising:

a first terminal connected to the first signal path and a second terminal connected to the second signal path to provide a differential port.

4. The system of claim 1 wherein the conductive segments are straight-line strips for forming the untwisted portion.

5. The system of claim 1 wherein the links are slanted-line strips for forming the twisted portion.

6. A differential transmission line system comprising:

a first planar differential twisted transmission line having a first twisted portion and a first successive untwisted portion for forming a virtual twisted pair without making an electrical connection;

a second planar differential twisted transmission line having a second twisted portion and a second successive untwisted portion for forming a virtual twisted pair without making an electrical connection wherein the first and second twisted portions are off-set from each other, each said planar differential twisted transmission line comprising,

insulated conductive layers;

first, second, third and fourth conductive planar segments formed from the conductive layers;

a first conductive link joining the first and second planar conductive segments to provide a first signal path;

a second conductive link joining the third and fourth planar conductive segments to provide a second signal path and the first and second conductive links operatively arranged to form the twisted portion in the first and second signal paths;

the conductive layers comprising first and second conductive layers, the second conductive layer disposed below the first conductive layer, the first planar conductive segment comprising a first forcated member having forked sides formed from the first conductive layer;

the second planar conductive segment comprising a second forcated member having forked sides, narrower than the first forcated member, formed from the second conductive layer;

the first link comprising at least one conductive through-hole formed through the forked sides for connecting the first and second forked members front-to-front and in longitudinal alignment, on the first and second conductive layer to form the twisted portion and the successive untwisted portion;

the third planar conductive segment includes a narrow strip formed form the second conductive layer and fitting centrally within the forked side;

the fourth planar conductive segment includes a substantially wide strip formed from the first conductive layer and fitting centrally within the forked sides; and

the second link comprising a conductive through-hole formed through the strips for connecting the strips front-to-front and in longitudinal alignment, on the first and second conductive layers, to form the twisted portion and the successive untwisted portion.

7. A parallel system of twisted-pair conductor line structures comprising:

an insulating layer;

a plurality of parallel twisted-pair differential transmission lines closely spaced together on said insulating layer, each twisted-pair differential transmission line comprising;

a plurality of first conductors positioned to extend substantially parallel on a first side of said substrate, each conductor of said plurality of said first conductors alternately connected with a plurality of first conductive links;

a plurality of second conductors positioned to extend substantially parallel on a second side of said substrate, each conductor of said plurality of second conductors alternately connected with a plurality of second conductive links; and

a plurality of crossing portions formed by said plurality of first conductive links and said plurality of second conductive links, said first conductive links and said second conductive links crossing each other on said first side of said insulating layer and said second side of said insulating layer respectively without making physical contact to form said twisted-pair differential transmission line.

8. The parallel system as in claim 7 wherein said plurality of parallel twisted-pair differential transmission lines are oriented so said plurality of crossing sections are offset for reducing coupling between signals present on said plurality of parallel twisted-pair differential transmission lines.

9. The parallel system as in claim 7 wherein said insulating layer is formed on a semiconductor substrate.