Microwave window with a two part metallic frame having different coefficients of thermal expansion
View Patent ↗An RF feed-through connector has a single pin or multi-pins supported and hermetically sealed between a first portion of the connector facing the hermetically sealed interior portion of an electronics-containing housing and a second portion of the connector exposed to ambient conditions in which the electronics-containing housing is placed. The invention is particularly directed to a new hermetically sealed RF feed-through connector architecture in which the connector's outer shell contains a relatively low coefficient of thermal expansion (CTE) portion that enables it to be soldered to a low CTE insert that supports one or more hermetically sealed longitudinal signal pins. The connector's outer shell also includes a relatively high CTE portion that allows the shell to be readily joined as by welding to an adjacent support structure, such as a relatively high CTE aluminum housing and the like.
1. A microwave window structure comprising a generally annular metallic frame that has an aperture therethrough, said frame containing a first metallic portion of a first coefficient of thermal expansion (CTE), and a second metallic portion of a second CTE lower than said first CTE, joined with said first metallic portion, a microwave transmission window containing a layer of solder-compatible material around a peripheral portion thereof, and being sized to cover said aperture when placed against said second metallic portion of said generally annular metallic frame, and a layer of solder that joins and hermetically seals said peripheral portion of said microwave transmission window to said second metallic portion of said generally annular frame, in which said first metallic portion has a notch or a groove extending around the annular frame to a depth that approaches the boundary between the first and second metallic portions.
2. The microwave window structure according to claim 1 , wherein said second metallic portion of said metallic frame has a depression therein that is sized to engage and seat said peripheral portion of said microwave transmission window.
3. The microwave window structure according to claim 2 , wherein said first metallic portion of said generally annular metallic frame has a generally planar surface that is metallurgically bonded to a first, generally planar surface of said second metallic portion of said generally annular frame, and wherein said second metallic portion of said generally annular frame has a second, generally planar surface that is spaced apart from the first, generally planar surface thereof by the thickness of said second metallic portion of said generally annular frame therebetween, and wherein said depression is formed in said second, generally planar surface of said second metallic portion of said annular frame.