Planar mixed-signal circuit board

• US 7,471,175 B2
• Filed: 04/26/2007
• Issued: 12/30/2008
• Est. Priority Date: 04/26/2006
• Status: Expired due to Fees

• Current Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Original Assignee: EMS Technologies, Inc. (Honeywell International Inc.)
• Inventors: Voss, John D.
• Primary Examiner(s): Le; Don P
• Application Number:
  US11/796,148
• Publication Number:
  US 20070262836A1
• Time in Patent Office: 614 Days
• Field of Search: 333236-240, 333245-247
• US Class Current: 333/247
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01P 3/081 Microstriplines
• CPC Class Codes: H01P 3/085 Triplate lines
• CPC Class Codes: H01P 3/087 Suspended triplate lines
• CPC Class Codes: H01P 3/088 Stacked transmission lines
• CPC Class Codes: H05K 1/0218 by printed shielding conductors, ground planes or power plane H05K1/0236 takes precedence
• CPC Class Codes: H05K 1/024 Dielectric details, e.g. changing the dielectric material around a transmission line
• CPC Class Codes: H05K 1/0298 Multilayer circuits
• 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

Abstract

A mixed-signal circuit board can provide a flexible arrangement of multiple RF transmission mediums in a single lightweight and compact structure as well as support embedding electronic devices within RF transmission paths. The transmission mediums may include a voided waveguide, a dielectric waveguide, a microstrip, a suspended microstrip, a traditional stripline, and a suspended stripline. The center conductors in each transmission medium may be constructed on the same plane or the same PCB layer in order to simplify coplanar design. A distribution board can be provided to deliver the power supply and control signals to the active electronic devices placed in the signal path of the RF board for signal processing and within covered cavities provided within the RF board.

Claims

1. A mixed signal circuit board comprising:

a distribution circuit board;

an RF circuit board disposed upon the distribution circuit board and comprising one or more RF signal paths, wherein the RF circuit board is formed around each RF signal path to provide vertical surfaces adjacent to each RF signal path and along a substantial length of each RF signal path; and

a conductive plating substantially surrounding the one or more RF signal paths including the vertical surfaces.

2. The circuit board of claim 1, wherein each RF signal path comprises a first transmission line and a second transmission line, wherein the first transmission line is a suspended stripline conductor, and the second transmission line is a microstrip conductor coplanar with the first transmission line.

3. The circuit board of claim 1, wherein each RF signal path comprises a first transmission line and a second transmission line, wherein the first transmission line is a stripline conductor, and the second transmission line is a suspended microstrip conductor coplanar with the first transmission line.

4. The circuit board of claim 1, wherein each RF signal path comprises a first transmission line and a second transmission line, wherein the first transmission line is a suspended stripline conductor, and the second transmission line is a suspended microstrip conductor coplanar with the first transmission line.

5. The circuit board of claim 1, wherein the each RF signal path comprises a first transmission line and a second transmission line, wherein the first transmission line is a suspended stripline conductor, and the second transmission line is a waveguide conductor coplanar with the first transmission line.

6. The circuit board of claim 1, wherein each RF signal path comprises a first transmission line and a second transmission line, wherein the first transmission line is a waveguide conductor, and the second transmission line is a microstrip conductor coplanar with the first transmission line.

7. The circuit board of claim 1, wherein each RF signal path comprises a first transmission line and a second transmission line, wherein the first transmission line and the second transmission line are independently one of a voided waveguide, a dielectric waveguide, a microstrip, a suspended microstrip, a traditional stripline, and a suspended stripline;

and the first transmission line is coplanar with the second transmission line.

8. The circuit board of claim 1 further comprising a control signal path and a power signal path for electrically conducting a control signal and a power signal through the distribution circuit board to the RF circuit board.

9. The circuit board of claim 1 further comprising a leveled via pad on the distribution circuit board for electrical interconnection with the RF circuit board.

10. The circuit board of claim 1, further comprising an aperture disposed within a bottom surface of the RF circuit board, wherein an electrical signal is connected from the distribution board to the RF board through the aperture.

11. The circuit board of claim 1, further comprising:

a cavity disposed within the RF circuit board;

an electronic device disposed within the cavity and in electrical communication with the RF circuit board; and

a conductive cap affixed to the RF circuit board and operable to cover the cavity.

12. An RF circuit board comprising:

at least one RF signal path, each comprising an RF transmission line;

a plurality of layers of RF circuit board substrate shaped to support the transmission line and an area adjacent to the transmission line; and

a conductive plating substantially surrounding each RF signal path.

13. The circuit board of claim 12, wherein each RF signal path comprises a first transmission line and a second transmission line, wherein the first transmission line and the second transmission line are independently one of a voided waveguide, a dielectric waveguide, a microstrip, a suspended microstrip, a traditional stripline, and a suspended stripline;

and the first transmission line is coplanar with the second transmission line.

14. The circuit board of claim 12 further comprising an aperture disposed within a bottom surface of one of the RF signal paths, wherein an electrical signal is connected to the RF circuit board through the aperture.

15. The circuit board of claim 12 further comprising:

a cavity disposed within one of the RF signal paths;

an electronic device disposed within the cavity and in electrical communication with the RF signal path; and

a conductive cap affixed to the RF circuit board and operable to cover the cavity.

16. A process for manufacturing mixed-signal circuit board, comprising the steps of:

cutting individual layers of RF circuit board to shape of one or more RF signal paths;

laminating the individual layers of RF circuit board together;

plating the RF circuit board by substantially encapsulating the RF circuit board in an electrically conductive plating material; and

providing device pockets and interconnection apertures within the RF circuit board.

17. The process of claim 16 further comprising the steps of:

providing a distribution board comprising power and control signal paths; and

mounting the RF circuit board upon the distribution board.

18. The process of claim 16 further comprising the steps of:

providing a distribution board comprising power and control signal paths;

routing power and control signals through the power and control signal paths to the RF board.

19. The process of claim 16 further comprising the steps of:

populating electronic devices within device pockets;

electrically interconnecting the electronic devices with the RF circuit board.

20. The process of claim 16 further comprising the step of sealing a conductive cover over the device pocket to create a shielded cavity.