Noise filter

• US 5,431,987 A
• Filed: 11/01/1993
• Issued: 07/11/1995
• Est. Priority Date: 11/04/1992
• Status: Expired due to Term

• Current Assignee: Susumu Okamura
• Original Assignee: Susumu Okamura
• Inventors: Ikeda, Takeshi
• Primary Examiner(s): Ryan, Patrick J.
• Assistant Examiner(s): Lee, Kam F.
• Application Number:
  US08/146,527
• Time in Patent Office: 617 Days
• Field of Search: 428/209, 428/210, 428/901, 428/615, 428/620
• US Class Current: 428/209
• CPC Class Codes: H03H 1/0007 of radio frequency interference filters
• CPC Class Codes: H03H 2001/0064 comprising semiconductor material
• CPC Class Codes: H03H 2001/0078 comprising spiral inductor on a substrate
• CPC Class Codes: H03H 7/0115 comprising only inductors and capacitors H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence
• CPC Class Codes: H05K 1/0216 Reduction of cross-talk, noise or electromagnetic interference grounding H05K1/0215
• CPC Class Codes: H05K 1/16 incorporating printed electric components, e.g. printed resistor, capacitor, inductor
• CPC Class Codes: H05K 1/165 incorporating printed inductors
• CPC Class Codes: H05K 2201/1006 Non-printed filter
• CPC Class Codes: H05K 3/4644 by building the multilayer layer by layer, i.e. build-up multilayer circuits making via holes in the insulating layers H05K3/0011; special circuit boards as base or core whereon the multilayer is built H05K3/4602
• CPC Class Codes: Y10S 428/901 Printed circuit
• CPC Class Codes: Y10T 428/12493 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
• CPC Class Codes: Y10T 428/12528 Semiconductor component
• CPC Class Codes: Y10T 428/24917 including metal layer
• CPC Class Codes: Y10T 428/24926 including ceramic, glass, porcelain or quartz layer

Abstract

A noise filter used in a signal transmission or power supply circuit and the like for suppressing noise passing therethrough comprises a first spiral electrode formed on an insulating substrate and a second spiral electrode formed over the first spiral electrode by way of a dielectric layer. The noise filter could also include a dielectric layer formed over the first spiral electrode and the insulating substrate with the second spiral electrode formed in such a manner to partly overlap with the first spiral electrode. Preferably, a high purity semiconductor substrate having a large bulk resistance is used as the insulating substrate.

Claims

1. A noise filter characterized in that a first spiral electrode is formed on an insulating substrate and a second spiral electrode is formed on said first spiral electrode by way of dielectric layer.

3. A noise filter according to claim 1 characterized in that at least one end of one of said spiral electrode is grounded and both ends of the other spiral electrode are connected in series with a signal transmission circuit to operate in a normal mode.

5. A noise filter according to claim 1 characterized in that both ends of said both spiral electrodes are connected in series with a signal transmission circuit to operate in a common mode.

7. A noise filter according to claim 1 characterized in that a high purity semiconductor substrate is used as said insulating substrate.

9. A noise filter according to claim 3 characterized in that a high purity semiconductor substrate is used as said insulating substrate.

11. A noise filter according to claim 1 characterized in that a magnetic insulating substrate is used as said insulating substrate.

13. A noise filter according to claim 3 characterized in that a magnetic insulating substrate is used as said insulating substrate.

15. A noise filter according to claim 1 characterized in that a plurality of noise filters are formed as an integral part on an insulating substrate.

17. A noise filter according to claim 3 characterized in that a plurality of noise filters are formed as an integral part on an insulating substrate.

19. A noise filter according to claim 1 fabricated on said substrate which also includes fabricated IC circuits.

2. A noise filter characterized in that a first spiral electrode is formed on an insulating substrate, a dielectric layer is formed on said first spiral electrode and said insulating substrate, and a second spiral electrode is formed on said dielectric layer at least partly overlapping with said first spiral electrode.

4. A noise filter according to claim 2 characterized in that at least one end of one of said spiral electrode is grounded and both ends of the other spiral electrode are connected in series with a signal transmission circuit to operate in a normal mode.

6. A noise filter according to claim 2 characterized in that both ends of said both spiral electrodes are connected in series with a signal transmission circuit to operate in a common mode.

8. A noise filter according to claim 2 characterized in that a high purity semiconductor substrate is used as said insulating substrate.

10. A noise filter according to claim 4 characterized in that a high purity semiconductor substrate is used as said insulating substrate.

12. A noise filter according to claim 2 characterized in that a magnetic insulating substrate is used as said insulating substrate.

14. A noise filter according to claim 4 characterized in that a magnetic insulating substrate is used as said insulating substrate.

16. A noise filter according to claim 2 characterized in that a plurality of noise filters are formed as an integral part on an insulating substrate.

18. A noise filter according to claim 4 characterized in that a plurality of noise filters are formed as an integral part on an insulating substrate.

20. A noise filter according to claim 2 fabricated on said substrate which also includes fabricated IC circuits.