Radio frequency feedthrough seal and method

• US 5,170,142 A
• Filed: 09/09/1991
• Issued: 12/08/1992
• Est. Priority Date: 09/09/1991
• Status: Expired due to Fees

• Current Assignee: Stellex Microwave Systems, Inc. (Johnson Controls International plc)
• Original Assignee: Watkins Johnson Co. (Qorvo, Inc.)
• Inventors: Bier, Larry J.
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): Neyzari, Ali
• Application Number:
  US07/756,462
• Time in Patent Office: 456 Days
• Field of Search: 333/245, 333/246, 333/247, 333/248, 333/260, 333/263, 333/254, 333/255, 333/24 R, 333/182, 333/236, 361/392
• US Class Current: 333/245
• CPC Class Codes: H01P 5/085 Coaxial-line/strip-line transitions

Abstract

A hermetically sealed radio frequency feedthrough device is disclosed. The feedthrough includes a first ring of a glass material which bonds to a radio frequency device housing when heated. A second ring is also provided, the second ring does not melt and thereby contains the glass material to desired areas during heating.

Claims

1. A radio frequency hermetic feedthrough comprising:

(a) a center conductor pin with a central longitudinal axis;

(b) a first ring of low loss dielectric material surrounding a portion of said center pin at a first location on said central longitudinal axis; and

(c) a second ring surrounding said center pin at a second location on said central longitudinal axis which is axially adjacent to said first location (adjacent to said first ring), said second ring formed of a low loss dielectric material with a high melting point relative to said first ring.

2. A radio frequency feedthrough pin seal as in claim 1 wherein said first ring is of a glass material.

3. A radio frequency feedthrough pin seal as in claim 1 wherein said second ring is of a material selected from the following group:

quartz, boron nitride.

4. A radio frequency hermetic feedthrough comprising:

(a) a center conductor pin with a central longitudinal axis;

(b) a first ring of a low loss dielectric material surrounding a portion of said pin at a fist location said central longitudinal axis; and

(c) a second ring surrounding said center pin at a second location on said central longitudinal axis which is axially adjacent to said first location(adjacent to said first ring), said second ring formed of a material with a low loss tangent, a high melting temperature relative to said first ring, and a dielectric constant substantially close to the dielectric constant of said first ring.

5. A radio frequency hermetic feedthrough comprising:

(a) a coaxial center pin insert comprising;

1. a radio frequency feedthrough pin with a central longitudinal axis;

2. a first ring of a low loss material surrounding a portion of said feedthrough pin at a first location on said central longitudinal axis; and

3. a second ring surrounding said feedthrough pin at a second location on said central longitudinal axis which is axially adjacent to said first location (adjacent to said first ring), said second ring formed of a material with a low loss tangent, high melting temperature relative to said first ring, and a dielectric constant substantially close to the dielectric constant of said first ring; and

(b) a radio frequency device comprising;

1. a housing defining a cavity for holding said insert, said cavity including an airline section to improve transition from said center pin to said device.

6. A radio frequency hermetic feedthrough as in claim 5 wherein said radio frequency device further includes a discontinuity capacitance compensation section located in said cavity to compensate for the discontinuity between said second ring and said airline section.

7. A method of forming a hermetic radio frequency connection comprising the steps of:

(a) inserting a coaxial pin (insert) into a feedthrough housing, said coaxial pin (insert) comprising a radio frequency feedthrough pin with a central longitudinal axis, a first ring of a low loss glass material surrounding said pin at a first location on said central longitudinal axis, a second ring surrounding said feedthrough pin at a second location on said central longitudinal axis which is axially adjacent to said first location (adjacent to said first ring), said second ring formed of a material with a low loss tangent, high melting temperature relative to said first ring, and a dielectric constant substantially close to the dielectric constant of said first ring; and

(b) heating said insert so that said first ring melts and adheres to the walls of said housing while said second ring remains in a solid form.