Nyquist's and Thevenin's Theorems Generalized for Nonreciprocal Linear Networks
Abstract
It is shown that an Nnode nonreciprocal linear network, with a system of internal thermal noise generators at temperature T, is equivalent to the sourcefree network together with a set of correlated nodal current generators, with infinite internal impedance, such that <i_{r}is*>_{Av}dν=2kT(yrs+ysr*)dν where y_{rs} is an element of the network admittance matrix and i_{r} is the rth nodal noise current with frequency v. The noise sources can also be represented by a system of nodal voltage generators, with infinite internal admittance, such that <v_{r}vs*>_{Av}dν=2kT(zrs+zsr*)dν.
The application of these results to a system of coupled antennas in an equithermal enclosure is noted and necessary conditions for the realizability of passive nonreciprocal networks are derived.
 Publication:

Journal of Applied Physics
 Pub Date:
 May 1955
 DOI:
 10.1063/1.1722048
 Bibcode:
 1955JAP....26..599T