DocumentCode :
892371
Title :
Thermal Noise from a Passive Linear Multiport
Author :
Wait, David F.
Volume :
16
Issue :
9
fYear :
1968
fDate :
9/1/1968 12:00:00 AM
Firstpage :
687
Lastpage :
691
Abstract :
The thermal noise from passive multiports is discussed from fundamentals so that it can be understood, measured, or calculated by a microwave engineer. The multiports are assumed to have a uniform temperature, but with no restriction on reciprocity or mismatch. The noise temperature, TN, contributed by such a multiport is TN=A T where T is its physical temperature and A is its absorption coefficient. An approximate method of measuring A, and a method of measuring an A as small as 0.008 within 5 percent, are pointed out. Also, exact and approximate expressions for A in terms of scattering matrix elements and termination reflection coefficients are derived. Finally, the crosscorrelation of the noise from different ports is briefly considered.
Keywords :
Acoustic reflection; Bandwidth; Electromagnetic wave absorption; Extraterrestrial measurements; Microwave measurements; NIST; Noise measurement; Scattering; Temperature; Thermal engineering;
fLanguage :
English
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9480
Type :
jour
DOI :
10.1109/TMTT.1968.1126772
Filename :
1126772
Link To Document :
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