Hermetic glass bead assembly having high frequency compensation

• US 20050191869A1
• Filed: 03/01/2004
• Published: 09/01/2005
• Est. Priority Date: 03/01/2004
• Status: Active Grant

• Current Assignee: Anritsu Corporation
• Original Assignee: Anritsu Corporation
• Inventors: Oldfield, William W., Moberg, Maurice W.
• Granted Patent: US 7,011,529 B2
• Time in Patent Office: Days
• US Class Current: 439/63
• CPC Class Codes: H01R 2103/00 Two poles
• CPC Class Codes: H01R 24/44 comprising impedance matching means

Abstract

Methods and devices in accordance with the present invention can comprise forming an electrical feed-through assembly to provide a hermetic seal in a coaxial connector. In one embodiment, the electrical feed-through assembly comprises a conductive insert having a bore, a dielectric insert positioned within the bore having a first diameter sized such that an impedance of the dielectric insert is a target impedance, the dielectric insert having a center conductive pin extending there-through, and an air dielectric positioned within the bore, the air dielectric having a second diameter sized such that an impedance of the air dielectric is the target impedance, a portion of the air dielectric extending into the dielectric insert, wherein the portion of the air dielectric extending into the dielectric insert is a compensation gap.

Claims

1. An electrical feed-through assembly to provide a hermetic seal in a coaxial connector, comprising:

a conductive insert having a bore;

a dielectric insert positioned within the bore having a first diameter sized such that an impedance of the dielectric insert is a target impedance;

a center conductor pin extending through the dielectric insert;

an air dielectric positioned within the bore having a second diameter sized such that an impedance of the air dielectric is the target impedance; and

a compensation gap positioned between the dielectric insert and the air dielectric, the compensation gap having an impedance larger than the target impedance;

wherein the compensation gap is a recess formed within the dielectric insert.

2. The electrical feed-through assembly of claim 1, wherein the dielectric insert comprises a glass bead.

3. The electrical feed-through assembly of claim 1, wherein the conductive insert comprises a conductive metal.

4. The electrical feed-through assembly of claim 3, wherein the conductive insert comprises Kovar.

5. The electrical feed-through assembly of claim 1, further comprising a sleeve positioned within the bore, wherein the dielectric insert is formed in the sleeve.

6. The electrical feed-through assembly of claim 5, wherein the sleeve is positioned within the bore by soldering.

7. The electrical feed-through assembly of claim 5, wherein the dielectric insert is formed by molding.

8. The electrical feed-through assembly of claim 1, wherein the dielectric insert is formed in the bore.

9. The electrical feed-through assembly of claim 8, wherein the dielectric insert is formed by molding.

10. An electrical feed-through assembly to provide a hermetic seal in a coaxial connector, comprising:

a conductive insert having a bore and a cavity within the bore, the cavity surrounding a portion of the bore;

a dielectric insert positioned within the bore having a diameter sized such that an impedance of a portion of the dielectric insert is a target impedance, the dielectric insert extending into the cavity;

a center conductor pin extending through the dielectric insert;

an air dielectric positioned within the bore, the air dielectric having a diameter sized such that an impedance of a portion of the air dielectric is the target impedance; and

a compensation gap formed between the glass dielectric and the air dielectric, such that at least a portion of the compensation gap is surrounded by the cavity.

11. The electrical feed-through assembly of claim 10, wherein the dielectric insert comprises a glass bead.

12. The electrical feed-through assembly of claim 10, wherein the conductive insert comprises a conductive metal.

13. The electrical feed-through assembly of claim 10, wherein the conductive insert comprises Kovar.

14. The electrical feed-through assembly of claim 10, wherein the dielectric insert is formed within the bore.

15. The electrical feed-through assembly of claim 14, wherein the dielectric insert is formed by molding.

24. The electrical feed-through assembly of claim 10, wherein an impedance of the compensation gap is higher than the target impedance.

16. A dielectric insert assembly to provide a hermetic seal in a coaxial connector, comprising:

a substantially cylindrical sleeve having a first inner diameter;

a dielectric insert formed within the sleeve, the dielectric insert having a first end and a second end;

a center conductor pin extending through the dielectric insert; and

a compensation gap extending into the second end of the dielectric insert, the compensation gap having a second diameter smaller than the first inner diameter;

wherein a portion of the center conductor pin extends through the compensation gap.

17. The dielectric insert assembly of claim 16, wherein the dielectric insert comprises a glass bead.

18. The dielectric insert assembly of claim 16, wherein the sleeve comprises a conductive metal.

19. The dielectric insert assembly of claim 16, wherein the dielectric insert is formed by molding.

25. The electrical feed-through assembly of claim 16, wherein:

an impedance of a portion of the dielectric insert is a target impedance;

an impedance of the compensation gap is higher than the target impedance.

20. A method of forming a dielectric insert assembly for insertion into an electrical feed-through assembly including a conductive insert having a bore to provide a hermetic seal in a coaxial connector, comprising:

positioning a sleeve so that the sleeve can be filled;

positioning a molded compensation step concentrically within the sleeve, the molded compensation step having a diameter smaller than an inner diameter of the sleeve;

positioning a center conductor pin within the molded compensation step so that the center conductor pin is approximately centered axially within the sleeve;

flowing a liquefied dielectric into the sleeve such that the liquefied dielectric substantially fills unoccupied space within the sleeve;

cooling the liquefied dielectric such that a dielectric insert is formed within the sleeve having the center conductor pin extending there-through; and

removing the molded compensation step from within the sleeve.

21. A method of forming an electrical feed-through assembly including a conductive insert having a bore having a first portion with a diameter sized such that an impedance of an air dielectric formed in the first portion is a target impedance and a second portion with a diameter sized such that an impedance of a glass dielectric formed in the second portion is the target impedance, the method comprising:

positioning a plug within the first portion of the bore;

positioning a center conductor pin within the plug so that when the plug is positioned within the bore, the center conductor pin is approximately centered axially within the bore;

flowing a liquefied dielectric into the conductive insert such that the liquefied dielectric fills the second portion of the bore not occupied by the plug;

cooling the liquefied dielectric; and

removing the plug from within the bore.

22. A method of forming an electrical feed-through assembly including a conductive insert having a bore having a first portion with a diameter sized such that an impedance of an air dielectric formed in the first portion is a target impedance and a second portion with a diameter sized such that an impedance of a glass dielectric formed in the second portion is the target impedance, the method comprising:

positioning a plug within the first portion of the bore such that the plug extends partially into the second portion of the bore;

positioning a center conductor pin within the plug so that when the plug is positioned within the bore, the center conductor pin is approximately centered axially within the bore;

flowing a liquefied dielectric into the conductive insert such that the liquefied dielectric fills the second portion of the bore not occupied by the plug;

cooling the liquefied dielectric; and

removing the plug from within the bore.

23. A method of forming an electrical feed-through assembly including a conductive insert having a bore having a first portion with a diameter sized such that an impedance of an air dielectric formed in the first portion is a target impedance and a second portion with a diameter sized such that an impedance of a glass dielectric formed in the second portion is the target impedance, the bore further having a cavity extending from the first portion such that the cavity surrounds a portion of the second portion, the method comprising:

positioning a plug within the first portion of the bore;

positioning a center conductor pin within the plug so that when the plug is positioned within the bore, the center conductor pin is approximately centered axially within the bore;

flowing a liquefied dielectric into the conductive insert such that the liquefied dielectric fills the second portion of the bore and the cavity;

cooling the liquefied dielectric; and

removing the plug from within the bore.

26. An electrical feed-through assembly to provide a hermetic seal in a coaxial connector, comprising:

a conductive insert having a bore and a cavity extending from the bore;

a dielectric insert disposed within the bore, the dielectric insert having a diameter sized such that an impedance of a portion of the dielectric insert is a target impedance;

a choke extending from the dielectric insert and disposed within the cavity;

an air dielectric positioned within the bore, the air dielectric having a diameter sized such that an impedance of a portion of the air dielectric is the target impedance; and

a center conductor pin extending through the dielectric insert and the air dielectric;

wherein at least a portion of the air dielectric is coincident with the choke along the center conductor pin; and

wherein the portion of the air dielectric coincident with the choke along the center conductor pin is a compensation gap.

27. A coaxial connector assembly comprising:

a package housing;

a microstrip disposed within the package housing;

an electrical feed-through assembly mounted in the package housing, the electrical feed-through assembly including;

a conductive insert having a bore,

a dielectric insert positioned within the bore having a first diameter sized such that an impedance of the dielectric insert is a target impedance,

a center conductor pin extending through the dielectric insert,

an air dielectric positioned within the bore having a second diameter sized such that an impedance of the air dielectric is the target impedance, and

a compensation gap positioned between the dielectric insert and the air dielectric, the compensation gap having an impedance larger than the target impedance,

wherein the compensation gap is a recess formed within the dielectric insert;

wherein the center conductor pin is in electrical communication with the microstrip.

28. A coaxial connector assembly comprising:

a package housing;

a microstrip disposed within the package housing;

an electrical feed-through assembly mounted in the package housing, the electrical feed-through assembly including;

a conductive insert having a bore and a cavity extending from the bore,

a dielectric insert disposed within the bore, the dielectric insert having a diameter sized such that an impedance of a portion of the dielectric insert is a target impedance,

a choke extending from the dielectric insert and disposed within the cavity;

an air dielectric positioned within the bore, the air dielectric having a diameter sized such that an impedance of a portion of the air dielectric is the target impedance, and

a center conductor pin extending through the dielectric insert and the air dielectric,

wherein at least a portion of the air dielectric is coincident with the choke along the center conductor pin,

wherein the portion of the air dielectric coincident with the choke is a compensation gap;

wherein the center conductor pin is in electrical communication with the microstrip.