On the Brune Process for n-Ports

The Brune process for
n
-ports, established by Oono, McMillan, and Tellegen, is derived by an alternative method based on successive series and shunt extractions of passive
n
-ports containing fictitious complex resistances, which are finally eliminated by a simple equivalence transformation. The method is also applied to nonreciprocal
n
-ports, thus establishing that such an
n
-port of degree
m
is realizable with not more than
m
reactive elements. For reciprocal
n
-ports, the new derivation of Brune's process clarifies the physical structure of the reactive
2n
-port generalizing Brune's section and yields explicit formulas for its element values.