Inductor topologies and decoupling structures for filters used in broadband applications, and design methodology thereof

• US 20040027212A1
• Filed: 03/28/2003
• Published: 02/12/2004
• Est. Priority Date: 03/29/2002
• Status: Active Grant

• Current Assignee: MACOM Technology Solutions Holdings, Inc.
• Original Assignee: M/A Com Eurotec BV (MACOM Technology Solutions Holdings, Inc.)
• Inventors: DeBhailis, Deirdre Anne, Solski, Piotr Miroslaw, Keeney, Bill Allen
• Granted Patent: US 7,259,639 B2
• Time in Patent Office: Days
• US Class Current: 333/132
• CPC Class Codes: H01F 17/0006 Printed inductances printed coils for dynamo-electric machines H02K3/26; printed circuits H05K
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H03H 7/0123 comprising distributed impedance elements together with lumped impedance elements
• CPC Class Codes: H05K 1/0231 Capacitors or dielectric substances
• CPC Class Codes: H05K 1/141 One or more single auxiliary printed circuits mounted on a main printed circuit, e.g. modules, adapters H05K1/142 and H05K1/147 take precedence
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 2201/086 for inductive purposes, e.g. printed inductor with ferrite core
• CPC Class Codes: H05K 2201/09063 Holes or slots in insulating substrate not used for electrical connections
• CPC Class Codes: H05K 2201/09181 Notches in edge pads
• CPC Class Codes: H05K 2201/1006 Non-printed filter
• CPC Class Codes: H05K 2203/171 Tuning, e.g. by trimming of printed components or high frequency circuits
• CPC Class Codes: H05K 3/0052 Depaneling, i.e. dividing a panel into circuit boards; Working of the edges of circuit boards
• CPC Class Codes: H05K 3/3442 having edge contacts, e.g. leadless chip capacitors, chip carriers
• CPC Class Codes: H05K 3/403 Edge contacts; Windows or holes in the substrate having plural connections on the walls thereof H05K3/4092 takes precedence

Abstract

Inductor topologies for filters used in broadband applications are described. In one implementation, an apparatus, such as an interface module includes a printed circuit board and a filter. The filter includes a generally circular high Quality factor (Q) value spiral planar inductor etched directly into the printed circuit board. The generally circular high Q value spiral planar inductor is configured to operate in a broadband application. Other implementations involve the use of decoupling structures with respect to the planar inductors as well as a design methodology for the filters.

Claims

1. An apparatus, comprising:

a printed circuit board; and

a filter comprising a generally circular high Quality factor (Q) value spiral planar inductor etched directly into the printed circuit board, the generally circular high Q value spiral planar inductor configured to operate in a broadband application.

2. The apparatus as recited in claim 1, wherein the apparatus is a broadband interface module.

3. The apparatus as recited in claim 1, wherein the apparatus is a cable television module.

4. The apparatus as recited in claim 1, wherein the apparatus is an input and/or output filter.

5. The apparatus as recited in claim 1, wherein the apparatus is one of at least a diplexer, duplexer, and tri-plexer.

6. The apparatus as recited in claim 1, wherein the printed circuit board is an FR4 substrate.

7. The apparatus as recited in claim 1, wherein the generally circular high Q value spiral planar inductor is elliptical in shape.

8. An apparatus, comprising:

a printed circuit board; and

a filter, operable in a broadband communication interface application;

the filter comprising a high Quality factor (Q) value spiral planar inductor having generally circular conductive traces etched directly into the printed circuit board, wherein an outer most conductive trace wraps around inner conductive traces that form a spiral leading to an inner most conductive trace, wherein the inner most conductive trace wraps around a center portion of the inductor, the center portion having no conductive traces.

9. The apparatus as recited in claim 8, wherein the filter operates in a range from about 1-to-1000 MHz.

10. The apparatus as recited in claim 8, wherein the generally circular conductive traces form an ellipse.

11. The apparatus as recited in claim 8, wherein the conductive traces are spaced apart from each other.

12. The apparatus as recited in claim 8, wherein the filter comprises a plurality of the high Quality factor (Q) value spiral planar inductors.

13. The apparatus as recited in claim 8, wherein the apparatus is a broadband interface module.

14. The apparatus as recited in claim 8, wherein the apparatus is a cable television module.

15. The apparatus as recited in claim 8, wherein the apparatus is an input and/or output filter.

16. The apparatus as recited in claim 8, wherein the apparatus is one of at least a diplexer, duplexer, and tri-plexer.

17. The apparatus as recited in claim 8, wherein the printed circuit board is an FR4 substrate.

18. A diplexer, comprising:

a high pass filter and lower pass filter each comprising at least one a high Quality factor (Q) value spiral planar inductor etched onto a printed circuit board;

wherein the high Q value spiral planar inductor includes conductive traces etched directly into the printed circuit board forming an ellipse, wherein an outer most conductive trace wraps around inner conductive traces that form a spiral leading to an inner most conductive trace, wherein the inner most conductive trace wraps around a center portion of the inductor, the center portion having no conductive traces.

19. A high performance planar spiral inductor, comprising:

a plurality of generally circular conductive traces etched directly into a printed circuit board, wherein an outer most conductive trace wraps around inner conductive traces that form a spiral leading to an inner most conductive trace, wherein the inner most conductive trace wraps around a center portion of the inductor, the center portion having no conductive traces, wherein the high performance planar spiral inductor is for use in filter applications involving broadband applications.

20. The high performance planar spiral inductor as recited in claim 19, wherein the filter applications operate in a range from about 1-to-1000 MHz.

21. The high performance planar spiral inductor as recited in claim 19, wherein the inductor is configured to provide a self-resonant frequency for inductances of about 40 to 400 nH.

22. A high performance planar spiral inductor as recited in claim 19, wherein the generally circular conductive traces form an ellipse.

23. A method, comprising:

etching a generally circular planar spiral inductor into a printed circuit board, the generally circular planar spiral inductor for use in a filter used in a broadband application, wherein the inductor is not a torroidal inductor.

24. The method as recited in claim 23, further comprising etching a decoupling structure into the printed circuit board in proximity to the generally circular planar spiral inductor.

25. The method as recited in claim 23, wherein the broadband filter is an input and/or output filter.

26. The method as recited in claim 23, wherein the broadband filter is one of at least a diplexer, duplexer, and tri-plexer.

27. The method as recited in claim 23, wherein the printed circuit board is an FR4 substrate.

28. The method as recited in claim 23, wherein the generally circular planar spiral inductor is a high Quality factor (Q) value spiral planar inductor.

29. The method as recited in claim 23, wherein the generally circular planar spiral inductor is elliptical in shape.

30. The method as recited in claim 23, wherein the filter operates in a range from about 1-to-1000 MHz.

31. The method as recited in claim 23, wherein the etching of the generally circular planar spiral inductor into a printed circuit board comprises etching an outer most conductive trace around inner conductive traces to form a spiral that leads to an inner most conductive trace, wherein the inner most conductive trace wraps around a center portion of the generally planar spiral inductor, the center portion having no conductive traces.

32. The method as recited in claim 23, wherein the generally circular planar spiral inductor is configured to provide a self-resonant frequency for inductances of about 40 to 400 nH.

33. An apparatus, comprising:

a printed circuit board;

a filter comprising first and second generally circular high Quality factor (Q) value spiral planar inductors etched into the printed circuit board; and

a decoupling structure etched into the printed circuit board in proximity to the first and second generally circular high Q value spiral planar inductors configured to reduce unwanted electromagnetic coupling between the first and second generally circular high Q value spiral planar inductors when current flows through the first and second generally circular high Q value spiral planar inductors.

34. The apparatus as recited in claim 33, wherein the apparatus is a broadband interface module.

35. The apparatus as recited in claim 33, wherein the apparatus is a cable television module.

36. The apparatus as recited in claim 33, wherein the apparatus is an input and/or output filter.

37. The apparatus as recited in claim 33, wherein the apparatus is one of at least a diplexer, duplexer, and tri-plexer.

38. The apparatus as recited in claim 33, wherein the printed circuit board is an FR4 substrate.

39. The apparatus as recited in claim 33, wherein the first and second generally circular high Q value spiral planar inductors are elliptical in shape.

40. The apparatus as recited in claim 33, wherein the decoupling structure is a metal trace in the printed circuit board.

41. The apparatus as recited in claim 33, wherein the first and/or second generally circular high Q value spiral planar inductors induce current to flow in the decoupling structure thereby generating a magnetic field opposite that of magnetic fields generated by the first and/or second generally circular high Q value spiral planar inductors when current flows through the first and/or second generally circular high Q value spiral planar inductors.

42. An apparatus, comprising:

a printed circuit board;

a filter, operable in a broadband communication interface application;

the filter comprising a plurality of high Quality factor (Q) value spiral planar inductors each having generally circular conductive traces etched directly into the printed circuit board, wherein an outer most conductive trace wraps around inner conductive traces that form a spiral leading to an inner most conductive trace, wherein the inner most conductive trace wraps around a center portion of the inductor, the center portion having no conductive traces; and

a decoupling structure, etched into the printed circuit board in proximity to the plurality of high Q value spiral planar inductors, configured to reduce unwanted electromagnetic coupling to at least one of the a plurality of high Q value spiral planar inductors when current flows through one or more of the plurality of high Q value spiral planar inductors.

43. The apparatus as recited in claim 42, wherein the filter operates in a range from about 1-to-1000 MHz.

44. The apparatus as recited in claim 42, wherein the generally circular conductive traces form an ellipse.

45. The apparatus as recited in claim 42, wherein the conductive traces are spaced apart from each other.

46. The apparatus as recited in claim 42, wherein the decoupling structure is a metal trace in the printed circuit board.

47. The apparatus as recited in claim 42, wherein the apparatus is a broadband interface module.

48. The apparatus as recited in claim 42, wherein the apparatus is a cable television module.

49. The apparatus as recited in claim 42, wherein the apparatus is an input and/or output filter.

50. The apparatus as recited in claim 42, wherein the apparatus is one of at least a diplexer, duplexer, and tri-plexer.

51. The apparatus as recited in claim 42, wherein the printed circuit board is an FR4 substrate.

52. The apparatus as recited in claim 42, wherein at least one of the plurality of planar inductors induce current to flow in the decoupling structure thereby generating a magnetic field opposite that of magnetic fields generated by one or more of the a plurality of high Q value spiral planar inductors.

53. A diplexer, comprising:

a high pass filter and lower pass filter each comprising at least one a high Quality factor (Q) value spiral planar inductor etched onto a printed circuit board;

wherein the high Q value spiral planar inductor includes conductive traces etched directly into the printed circuit board generally forming an circle, wherein an outer most conductive trace wraps around inner conductive traces that form a spiral leading to an inner most conductive trace, wherein the inner most conductive trace wraps around a center portion of the inductor, the center portion having no conductive traces; and

a decoupling structure, etched into the printed circuit board in proximity to the high pass filter and/or the low pass filter, configured to reduce occurrences of unwanted electromagnetic coupling to the high pass filter and/or the low pass filter when current flows through the high pass filter and/or low pass filter.

54. The diplexer as recited in claim 53, wherein the decoupling structure is a metal trace in the printed circuit board.

55. The diplexer as recited in claim 53, wherein the printed circuit board is an FR4 substrate.

56. A method, comprising:

(a) designing a layout for a filter for use in a broadband application, the filter comprising generally circular high Quality factor (Q) value spiral planar inductors etched directly into a printed circuit board;

(b) simulating operational characteristics of the layout;

(c) quantifying coupling between the generally circular high Q value spiral planar inductors; and

(d) compensating for the coupling by (i) introducing decoupling structures into the layout, (ii) changing inductor values for at least one of the generally circular high Q value spiral planar inductors, and/or (iii) modifying the layout.

57. The method as recited in claim 56, further comprising:

re-simulating the layout; and

ascertaining whether the simulated operational characteristics of the layout are within desired performance targets.

58. The method as recited in claim 56, further comprising iteratively repeating operations performed in paragraphs (b), (c) and (d) until the layout operates within desired performance targets.

59. The method as recited in claim 56, wherein the simulating includes electromagnetic simulation.

60. The method as recited in claim 56, wherein the simulating includes radio frequency simulation.

61. The method as recited in claim 56, wherein the simulating includes using a lumped element simulator model in conjunction with electromagnetic simulation.

62. A method, comprising:

(a) designing a layout for a filter for use in a broadband application, the filter comprising generally circular high Quality factor (Q) value spiral planar inductors etched directly onto a printed circuit board;

(b) simulating operational characteristics of the layout, wherein the simulating includes using a lumped element simulator model in conjunction with electromagnetic simulation;

(c) quantifying coupling between the generally circular high Q value spiral planar inductors; and

(d) compensating for the coupling by (i) introducing decoupling structures into the layout, (ii) changing inductor values for at least one of the generally circular high Q value spiral planar inductors, and/or (iii) modifying the layout.

63. The method as recited in claim 62, further comprising photo-etching (i) the generally circular high Q value spiral planar inductors into a printed circuit board in accordance with the simulated layout.

64. The method as recited in claim 62, further comprising photo-etching at least one decoupling structure into the printed circuit board in proximity to at least one of the generally circular high Q value spiral planar inductors.

65. The method as recited in claim 62, wherein at least one of the generally circular high Q value spiral planar inductors is elliptical in shape.

66. A method, comprising:

(a) designing a layout for a filter for use in a broadband application, the filter comprising generally circular high Quality factor (Q) value spiral planar inductors etched directly onto a printed circuit board;

(b) simulating operational characteristics of the layout, wherein the simulating includes using a lumped element simulator model in conjunction with electromagnetic simulation;

(c) quantifying coupling between the generally circular high Q value spiral planar inductors; and

(d) compensating for the coupling by (i) introducing decoupling structures into the layout, (ii) changing inductor values for at least one of the generally circular high Q value spiral planar inductors, and/or (iii) modifying the layout.

67. The method as recited in claim 66, further comprising photo-etching (i) the generally circular value spiral planar inductors into a printed circuit board in accordance with the simulated layout.

68. The method as recited in claim 66, further comprising photo-etching at least one decoupling structure into the printed circuit board in proximity to at least one of the generally circular high Q value spiral planar inductors.

69. The method as recited in claim 66, wherein at least one of the generally circular high Q value spiral planar inductors is elliptical in shape.

70. A method, comprising:

(a) synthesizing a filter design for a broadband application to produce values for inductors used in the filter;

(b) designing generally circular high Quality factor (Q) value spiral planar inductors with values that match the values obtained from the synthesizing, each of the generally circular high Q value spiral planar inductors are configured to be etched directly into a printed circuit board;

(c) electro magnetically simulating operation of each of the generally circular high Q value spiral planar inductors;

(d) quantifying coupling between the generally circular high Q value spiral planar inductors; and

(e) adjusting the coupling and/or inductance values assigned to the generally circular high Q value spiral planar inductors until electromagnetic simulated operation of the generally circular high Q value spiral planar inductors match target operating characteristics for the synthesized filter design.

71. The method as recited in claim 70, further comprising using a behavior model in conjunction with the electromagnet simulation.