Waveguide windows made with polystyrene preformed plastic and sealed with foamed-in-place plastic are useful in any microwave waveguide system using cryogenic cooling

Clauss, R.

Stelzried, C. T.

English

NASA Technical Reports Server

June 1964
NASA TECH BRIEF
Brief 63-10613 
This NASA Tech Brief is issued by the Technology Utilization Division to acquaint industry 
with the technical content of an innovation derived from the NASA space program. 
Cryogenic Waveguide Window Is Sealed With Plastic Foam 
The problem: Microwave waveguide windows 
normally consist of thin dielectric membranes 
inserted between waveguide flanges. In microwave 
applications requiring the use of 'a cryogenically 
cooled waveguide, these windows receive condensa-
tion from the atmosphere and require special venting 
and sealing techniques. 
The solution: Waveguide windows made from 
foam plastic sealed with foamed-in-place plastic. 
How it's done: A 1- to 2-inch section of the 
waveguide is filled with polystyrene preformed 
plastic. A 1/16-inch coating of a foaming plastic 
mixture is applied to the outside end as a seal. As 
an example of the efficiency of this method, a 2-inch 
length of 511U brass waveguide (0.0119-db inser-
tion loss—open), when filled with polystyrene plastic 
and sealed with foamed-in-place plastic, has an inser-
tion loss of 0.020-db.
Notes: 
1. This method would be useful in any microwave 
waveguide system using cryogenic cooling, such 
as a radar system employing low-noise input 
receivers. 
2. Fabrication of this window requires no special 
tools and can be readily accomplished by electronic 
technicians. 
3. For further information about this innovation 
inquiries may be directed to: 
Technology Utilization Officer 
Jet Propulsion Laboratory 
4800 Oak Grove Drive 
Pasadena, California 91103 
Reference: B63-10613 
Patent status: NASA encourages commercial use 
of this innovation. No patent action is contemplated. 
Source: Charles T. Stelzried and Robert Clauss 
(JPL-559) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States Govern-
ment. nor NASA, nor any person acting on behalf of NASA: A. Makes 
any warranty or representation, express or implied, with respect to the 
accuracy, completeness, or usefulness of the information contained in
this document, or that the use of any information, apparatus, method, 
or process disclosed in this document may not infringe privately-owned 
rights: or B. Assumes any liabilities with respect to the use of, or for 
damages resulting from the use of, any information, apparatus, method. 
or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19630000127 2020-03-11T16:48:55+00:00Z


Cryogenic waveguide window is sealed with plastic foam

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