  In this paper, we analyze the fundamental trade-off between information
transfer and power gain by means of an information-theoretic framework in
communications circuits. This analysis is of interest as many of today's
applications require that maximum information and maximum signal power are
extracted (or transferred) through the circuit at the same time for further
processing so that a compromise concerning the signal spectral shape as well as
the matching network has to be found. To this end, the optimization framework
is applied to a two-port circuit, which is used as an abstraction for a
broadband amplifier. Thereby, we characterize the involved Pareto bound by
considering different optimization problems. The first one aims at optimizing
the input power spectral density (PSD) as well as the source and load
admittances, whereas the second approach assumes the PSD to be fixed and
uniformly distributed within a fixed bandwidth and optimizes the source and
load admittances only. Moreover, we will show that additional matching networks
may help to improve the trade-off.
