Distributed-element circuit: Difference between revisions

Revision as of 21:46, 26 December 2018

Revision as of 21:48, 26 December 2018

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[[File:Ferritzirkulator1.jpg|thumb|upright|alt=Square, grey, three-port device with an identifying sticker|A coaxial ferrite circulator operating at {{nowrap|1 GHz}}]]

{{main|Circulator}}

A circulator is usually a three- or four-port device in which power entering one port is transferred to the next port in rotation, as if round a circle. Power can only flow in one direction around the circle (clockwise or anticlockwise), and no power is transferred to any of the other ports. Most distributed element circulators are based on [[Ferrite (magnet)|ferrite]] materials.<ref>{{multiref|Sharma, pp. 175–176.|Linkhart, p. 29.}}.</ref> Uses of circulators include as an [[Isolator (microwave)|isolator]] to protect a transmitter (or other equipment) from damage due to reflections from the antenna, and as a [[duplexer]] connecting the antenna, transmitter and receiver of a radio system.<ref>{{multiref|Meikle, p. 91.|Lacomme ''et al.'', pp. 6–7.}}.</ref>

An unusual application of a circulator is in a reflection amplifier, where the [[negative resistance]] of a [[Gunn diode]] is used to reflect back more power than it received. The circulator is used to direct the input and output power flows to separate ports.<ref>Roer, pp. 255–256.</ref>