RF window including a prestressing ring that surrounds the periphery of a dielectric disc and applies a radial stress to the dielectric disc

Patent metadata

Field	Value
Publication number	US-10084221-B2
Application number	US-201615338244-A
Country	US
Kind code	B2
Filing date	Oct 28, 2016
Priority date	Nov 6, 2015
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

An RF frequency window comprises a dielectric disc, a main metal skirt brazed all the way around the periphery of the dielectric disc and a surrounding prestressing ring in contact with the main metal skirt around the periphery of the dielectric disc and applying, in the rest state, over the whole of the periphery of the dielectric disc, a radial compressive stress directed towards the center of the dielectric disc, the prestressing ring comprising a set of at least one cooling channel in the longitudinal direction of the prestressing ring.

First claim

The invention claimed is:

1. An RF frequency window comprising a dielectric disc, a main metal skirt brazed all the way around the periphery of the dielectric disc and a surrounding prestressing ring in contact with the main metal skirt around the periphery of the dielectric disc and applying, in the rest state, over the whole of the periphery of the dielectric disc, a radial compressive stress directed towards a center of the dielectric disc, the prestressing ring comprising at least one cooling channel in the longitudinal direction of the prestressing ring.

2. The RF frequency window according to claim 1 , wherein the prestressing ring comprises an annular zone and is part of a prestressing assembly bearing on an external surface of the main metal skirt around the periphery of the dielectric disc.

3. The RF frequency window according to claim 2 , wherein the prestressing ring is made of stainless steel.

4. The RF frequency window according to claim 2 , wherein the prestressing assembly comprises at least a part of a cooling circuit comprising the at least one cooling channel.

5. The RF frequency window according to claim 2 , wherein the prestressing assembly comprises components made of at least a metal that is more rigid than that of the main metal skirt.

6. The RF frequency window according to claim 1 , comprising an additional metal skirt inside the main metal skirt.

7. The RF frequency window according to claim 1 , wherein the prestressing ring has a thickness that is between 2 and 10 mm.

8. The RF frequency window according to claim 1 , comprising a lubricating substance interposed between the prestressing ring and the main metal skirt, in order to prevent sintering between the prestressing ring and the main metal skirt in the event of a rise in temperature of the prestressing ring.

9. The RF frequency window according to claim 1 , wherein the dielectric disc is made of ceramic.

10. The RF frequency window according to claim 1 , wherein the main metal skirt is made of copper.

11. The RF frequency window according to claim 1 , wherein the prestressing ring comprises a set of a plurality of cooling channels, and the at least one cooling channel is one cooling channel of the set of the plurality of cooling channels.

12. The RF frequency window according to claim 11 , wherein the set of the plurality of cooling channels have regular spacing.

13. The RF frequency window according to claim 11 , wherein the set of the plurality of cooling channels have an identical diameter of between 0.5 and 4 mm.

14. A method of manufacturing an RF frequency window consisting of:
placing a dielectric disc inside a main metal skirt, with a brazing material, and with a clearance between the periphery of the dielectric disc and the main metal skirts;
placing the dielectric disc and the main metal skirt inside a prestressing assembly comprising a prestressing ring pierced with at least one cooling channel, and the prestressing assembly surrounding the main metal skirt over the whole of the periphery of the dielectric disc;
forming a clearance between the prestressing ring and the main metal skirt;
placing a brazing hoop around the prestressing ring with a clearance between the hoop and the prestressing ring, the material of the hoop having a coefficient of expansion lower than a coefficient of expansion of the prestressing ring;
taking the hoop, prestressing ring, main metal skirt and dielectric disc assembly to a temperature ensuring the brazing of the dielectric disc in the main metal skirt; and
allowing the assembly to cool, the cooling ensuring a radial compressive prestressing of the prestressing ring on the main metal skirt and on the dielectric disc.

15. The method according to claim 14 , wherein, before placing the prestressing ring around the main metal skirt, a lubricating substance is interposed between the prestressing ring and the main metal skirt, preventing sintering between the prestressing ring and the main metal skirt in the event of a rise in temperature of the ring.

Assignees

• Thales Sa

Inventors

• Denis Philippe

Classifications

• H01P1/08 Primary

  Dielectric windows · CPC title

• H01P3/12

  Hollow waveguides (H01P3/20 takes precedence) · CPC title

• H01P1/30

  for compensation of, or protection against, temperature or moisture effects {; for improving power handling capability (H01P1/04, H01P1/08 take precedence)} · CPC title

• H01P1/042

  Hollow waveguide joints · CPC title

• H01P11/00

  Apparatus or processes specially adapted for manufacturing waveguides or resonators, lines, or other devices of the waveguide type · CPC title