Low profile filter

• US 6,822,845 B2
• Filed: 10/23/2003
• Issued: 11/23/2004
• Est. Priority Date: 10/23/2002
• Status: Active Grant

• Current Assignee: Spectrum Control Incorporated (API Technologies Corporation)
• Original Assignee: Spectrum Control Incorporated (API Technologies Corporation)
• Inventors: Chereson, Jeffrey D.
• Primary Examiner(s): Dinkins, Anthony
• Application Number:
  US10/692,131
• Publication Number:
  US 20040084199A1
• Time in Patent Office: 397 Days
• Field of Search: 361/302, 361/303, 361/306.1, 361/306.3, 361/328, 361/329, 361/330, 333/182-185, 29/254.1, 29/254.2
• US Class Current: 361/302
• CPC Class Codes: H01F 17/06 with core substantially closed in itself, e.g. toroid
• CPC Class Codes: H01F 2017/065 Core mounted around conductor to absorb noise, e.g. EMI filter
• CPC Class Codes: H01F 27/34 Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
• CPC Class Codes: H01F 27/36 Electric or magnetic shields or screens movable for varying inductance H01F21/10
• CPC Class Codes: H01F 27/363 made of electrically conductive material
• CPC Class Codes: H01G 4/40 Structural combinations of fixed capacitors with other electric elements, the structure mainly consisting of a capacitor, e.g. RC combinations
• CPC Class Codes: H01R 13/7197 with filters integral with or fitted onto contacts, e.g. tubular filters
• CPC Class Codes: H03H 2001/0042 Wound, ring or feed-through type capacitor
• CPC Class Codes: H03H 2001/005 Wound, ring or feed-through type inductor

Abstract

The invention may be embodied in an electromagnetic filter for use with a feedthrough conductor. An inductor having a metallized surface is disposed about the conductor, and a capacitor is joined to the inductor. One set of capacitor plates are electrically connected to a first conductive contact to provide a connection to the metallized surface. Another set of capacitor plates are electrically connected to a second conductive contact to provide a connection to the feedthrough conductor. A method of providing such a filter is also disclosed.

Claims

1. An electromagnetic filter comprising:

a feedthrough conductor;

an inductor disposed about the conductor and having a metallized surface;

a capacitor joined to the inductor, the capacitor being electrically connected to a first conductive contact which is electrically connected to the metallized surface, and the capacitor being electrically connected to a second conductive contact which is electrically connected to the feedthrough conductor.

2. The filter of claim 1, wherein the capacitor is disposed about the feedthrough conductor.

3. The filter of claim 2, wherein the capacitor is not disposed about the inductor.

4. The filter of claim 3, wherein the capacitor is disposed about a first axial location of the feedthrough conductor and the inductor is disposed about a second axial location of the feedthrough conductor, the first axial location being different from the second axial location.

5. The filter of claim 1, wherein the metallized surface joins the capacitor to the inductor.

6. The filter of claim 1, further comprising a non-metallic material joining the capacitor to the inductor.

7. The filter of claim 1, wherein the metallized surface is not positioned between the feedthrough conductor and the inductor.

8. The filter of claim 1, wherein the metallized surface is at a first electric potential and the conductor is at a second electric potential.

9. The filter of claim 1, further comprising at least one additional capacitor joined to the inductor, wherein both capacitors are disposed about a first axial location of the feedthrough conductor.

10. A pi-filter, comprising:

a first capacitor disposed about a conductor;

an inductor disposed about the conductor and joined to the first capacitor, the inductor having at least one metallized surface electrically connected to the first capacitor,

a second capacitor disposed about the conductor and joined to the inductor.

11. The pi-filter of claim 10, wherein first capacitor is at a first axial location with respect to the feedthrough conductor, the inductor is at a second axial location with respect to the feedthrough conductor, the second capacitor is at a third axial location with respect to the feedthrough conductor, and the second axial location is between the first and third axial locations.

12. The pi-filter of claim 10, wherein the metallized surface joins the first capacitor and the inductor.

13. The pi-filter of claim 10, wherein the second capacitor is electrically connected to the metallized surface.

14. The pi-filter of claim 10, further comprising a second metallized surface joined to the second capacitor.

15. The pi-filter of claim 10, wherein neither capacitor is disposed about the inductor.

16. The pi-filter of claim 10, wherein the metallized surface is not positioned between the feedthrough conductor and the inductor.

17. The pi-filter of claim 10, wherein the metallized surface is at a first electric potential and the conductor is at a second electric potential.

18. A method of providing an electromagnetic filter, comprising:

providing an inductor;

coating a portion of the inductor to provide a metallized surface on the inductor;

providing a capacitor that is electrically connected to a first conductive contact and a second conductive contact;

joining the capacitor to the inductor;

electrically connecting the first conductive contact to the metallized surface

electrically connecting the second conductive contact to the feedthrough conductor.