Distributed-element circuit: Difference between revisions

Revision as of 14:41, 3 October 2019

Revision as of 10:11, 9 October 2019

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{{main|Distributed-element filter}}

[[File:Microstrip Hairpin Filter And Low Pass Stub Filter.jpg|thumb|alt=See caption|upright=1.3|Microstrip [[band-pass]] hairpin filter ''(left)'', followed by a [[low-pass]] stub filter]]

Filters are a large percentage of circuits constructed with distributed elements. A wide range of structures are used for constructing them, including stubs, coupled lines and cascaded lines. Variations include interdigital filters, combline filters and hairpin filters. More-recent developments include [[fractal]] filters.<ref>Cohen, p. 220</ref> Many filters are constructed in conjunction with [[dielectric resonator]]s.<ref>{{multiref| Hong & Lancaster, pp. 109, 235|Makimoto & Yamashita, p. 2}}</ref>

As with lumped-element filters, the more elements used, the closer the filter comes to an [[brickwall filter|ideal response]]; the structure can become quite complex.<ref>Harrell, p. 150</ref> For simple, narrow-band requirements, a single resonator may suffice (such as a stub or [[spurline filter]]).<ref>Awang, p. 296</ref>

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==== Hybrids ====

[[File:Ratracecoupler-arithmetics.svg|thumb|upright|alt=Drawing of a four-port ring|Hybrid ring, used to produce sum and difference signals]]

A directional coupler which splits power equally between the output and coupled ports (a {{nowrap|3 [[decibel|dB]]}} coupler) is called a ''hybrid''.<ref>Maloratsky (2004), p. 117</ref> Although "hybrid" originally referred to a [[hybrid transformer]] (a lumped device used in telephones), it now has a broader meaning. A widely- used distributed-element hybrid which does not use coupled lines is the ''hybrid ring'' or [[rat-race coupler]]. Each of its four ports is connected to a ring of transmission line at a different point. Waves travel in opposite directions around the ring, setting up [[standing wave]]s. At some points on the ring, destructive [[wave interference|interference]] results in a null; no power will leave a port set at that point. At other points, constructive interference maximises the power transferred.<ref>Chang & Hsieh, pp. 197–198</ref>

Another use for a hybrid coupler is to produce the sum and difference of two signals. In the illustration, two input signals are fed into the ports marked 1&nbsp;and 2. The sum of the two signals appears at the port marked Σ, and the difference at the port marked Δ.<ref>Ghione & Pirola, pp. 172–173</ref> In addition to their uses as couplers and power dividers, directional couplers can be used in [[balanced mixer]]s, [[frequency discriminator]]s, [[Attenuator (electronics)|attenuator]]s, [[phase shifter]]s, and [[antenna array]] [[antenna feed|feed]] networks.<ref>{{multiref|Chang & Hsieh, p. 227|Maloratsky (2004), p. 117}}</ref>

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* Craig, Edwin C, ''Electronics via Waveform Analysis'', Springer, 2012 {{ISBN|1461243386}}.

* Doumanis, Efstratios; Goussetis, George; Kosmopoulos, Savvas, ''Filter Design for Satellite Communications: Helical Resonator Technology'', Artech House, 2015 {{ISBN|160807756X}}.

* DuHamell, R; Isbell, D, [https://doi.org/10.1109/IRECON.1957.1150566 "Broadband logarithmically periodic antenna structures"], ''1958 IRE International Convention Record'', New York, 1957, pp. &nbsp;119–128.

* Edwards, Terry C; Steer, Michael B, ''Foundations of Microstrip Circuit Design'', John Wiley & Sons, 2016 {{ISBN|1118936191}}.

* Fagen, M D; Millman, S, ''A History of Engineering and Science in the Bell System: Volume 5: Communications Sciences (1925–1980)'', AT&T Bell Laboratories, 1984 {{ISBN|0932764061}}.

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* Helszajn, J, ''Ridge Waveguides and Passive Microwave Components'', IET, 2000 {{ISBN|0852967942}}.

* Henderson, Bert; Camargo, Edmar, ''Microwave Mixer Technology and Applications'', Artech House, 2013 {{ISBN|1608074897}}.

* Hilty, Kurt, "Attenuation measurement", pp. &nbsp;422–439 in, Dyer, Stephen A (ed), ''Wiley Survey of Instrumentation and Measurement'', John Wiley & Sons, 2004 {{ISBN|0471221651}}.

* Hong, Jia-Shen G; Lancaster, M J, ''Microstrip Filters for RF/Microwave Applications'', John Wiley & Sons, 2004 {{ISBN|0471464201}}.

* Hunter, Ian, ''Theory and Design of Microwave Filters'', IET, 2001 {{ISBN|0852967772}}.

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{{featured article}}

[[Category:Distributed element circuits| ]]

[[Category:Radio electronics]]