[Antennas] Un-Uns
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[email protected]
2002年1月17日 04:58:24 EST
Tom,
broadband transformers can be divided into two categories named by their
inventors: Ruthroff (voltage type) and Guanella (current type). Ruthroff sums
a direct voltage with a delayed voltage whereas Guanella connects
transmission lines in parallel/series arrangements. There are UnUn and BalUn
versions of both types, voltage and current. For example, if you take a
Guanella 4:1 UnUn one of the two transmission lines is grounded on both ends,
so both ports (1R and 4R) are unbalanced and this transmission line only acts
as a delay line. If you disconnect the 4R- port from ground and let it float
the configuration becomes a 4:1 BalUn. See Jerry Sevick's outstanding
presentation of that topic a series of articles in CQ magazine 1993/94.
73
Karl, DJ5IL