Transmission-line is coaxial. Its outer conductor is made of thin-wall stainless-steel tube; inside is plated with 0.0025 mm copper and 0.0003 mm gold. This combination gives little microwave loss and adequate thermal isolation

Clauss, R. C.

Wiebe, E. R.

English

NASA Technical Reports Server

Input Transmission-Line Assembly 
.
0-Ring 
Support Flange	 Vacuum 
fnrCE,tr	 Seal
4.5-K 
Heat Station 
and Clamp 
To Support 
Center 
Conductor 
Adapter 
Plate 
lnp' 
Wave 
Fusec 
0uart 
DomE 
June 1975	 B75-10126 
NASA TECH BRIEF S
NASA Pasadena Office 	 4r 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Transmission Line for S-Band Masers 
A new shortened transmission line has been 
developed for S-band masers. The result is reduced 
noise temperature at the maser input. 
The transmission-line assembly is shown in the 
illustration. The line is coaxial. Its outer conductor is 
made of a thin-wall (0.25-mm wall) stainless-steel 
tube; the inside is plated with 0.0025 mm copper and 
0.0003 mm gold. This combination gives little 
microwave loss and adequate thermal isolation. The 
transmission line is mechanically supported by 
clamping a flange at the room-temperature end of the
outer conductor, between the adapter plate and the 
waveguide. Thermal connections to the 80-K and 
4.5-K, closed-cycle, helium-refrigeration (CCR) sta-
tions are made with flexible copper straps. 
The transmission-line center conductor contacts the 
outer conductor at the 4.5-K temperature connector 
and at the support clamp (which is thermally 
connected to the 4.5-K CCR station). It is made of 
gold-plated, polished copper. A vacuum, common to 
the CCR vacuum jacket, provides thermal insulation 
between the coaxial-line center conductor and its 
surrounding outer conductor and the quartz dome. 
This document was prepared under the sponsorship of the National Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19750000126 2020-03-19T20:24:09+00:00Z
A fused quartz dome serves as part of the vacuum 2. Requests for further information may be directed 
seal. The quartz dome is attached and sealed to the to: 
input waveguide with flexible epoxy. An 0-ring seal is Technology Utilization Officer 
used between the waveguide and the adapter plate. NASA Pasadena Office 
The waveguide and fused quartz dome assembly can 4800 Oak Grove Drive 
be	 replaced	 without	 disturbing	 other	 input-line Pasadena, California 91103 
components. Reference: TSP75-10126
	 - 
Refrigeration capacity measurements show that the  
total heat transferred to the 4.5-K CCR station (by Patent status: 
radiation to the center conductor and by conduction This invention is owned by NASA, and a patent 
through the outer conductor) is approximately 100 application has been filed. Inquiries concerning non-
mW. The VSWR (voltage standing-wave ratio) of the exclusive or exclusive license for its commercial 
transmission-line and waveguide assembly is less than development should be addressed to: 
1.15 to 1 for frequencies from 2,050 to 2,650 MHz. Patent Counsel 
The overall system operating temperature is ,
 8.3 K. NASA Pasadena Office
	 S. 
4800 Oak Grove Drive 
Notes: Pasadena, California 91103 
1. A 2.1-K maser equivalent-input noise temperature -.	 - 
was achieved through the use of the new input Source: Robert C. Clauss and Ervin R. Wiebe of 
transmission line. At Goldstone, California, and Caltech/JPL 
at Canberra, Australia, 2.1-K masers were in- under contract to 
stalled on 64-m antennas. The improved systems ,.	 S	 NASA Pasadena Office 
(each with an overall system temperature of 13 K S	 (NPO-13504) 
with the antenna at zenith) enabled the reception
S 
of high data-rate television pictures from Mercury 
(by , Mariner spacecraft) in 1974. S	 - 
S	
.5	 S
Categories: 03 (Physical Sciences) 
B75-10126	 02 (Electronics Systems) 


Transmission line for S-band masers

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