On the Brune Process for n-Ports

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