In microwave circuits described by scattering parameters, it is
advantageous to regard noise as noise waves [5]. The noise
characteristics of an n-port is then defined completely by one
outgoing noise wave
at each port (see 2-port
example in fig. 2.1) and the correlation between these
noise sources. Therefore, mathematically, you can characterize a
noisy n-port by its
scattering matrix
and its
noise wave correlation matrix
.
Where
is the time average of
and
is the conjugate complex of
. Noise correlation
matrices are hermitian matrices because the following equations hold.
Im![]() ![]() |
(2.2) |
![]() |
(2.3) |
Where
Im is the imaginary part of
and
is the magnitude of
.