Distributed-element circuit: Difference between revisions

Revision as of 00:15, 3 October 2019

Revision as of 14:41, 3 October 2019

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=== Distributed resistance ===

Resistive elements are generally not useful in a distributed-element circuit. However, distributed resistors may be used in [[attenuator (electronics)|attenuatorsattenuator]]s and line [[electrical termination|terminations]]. In planar media they can be implemented as a meandering line of high-resistance material, or as a deposited patch of [[thin-film]] or [[thick-film]] material.<ref>{{multiref|Maloratsky (2012), p. 69|Hilty, p. 425|Bahl (2014), p. 214}}</ref> In waveguide, A card of microwave absorbent material can be inserted into the waveguide.<ref>Hilty, pp. 426–427</ref>

== Circuit blocks ==

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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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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)|attenuatorsattenuator]]s, [[phase shifter]]s, and [[antenna array]] [[antenna feed|feed]] networks.<ref>{{multiref|Chang & Hsieh, p. 227|Maloratsky (2004), p. 117}}</ref>

=== Circulators ===

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== Bibliography ==

* Ahn, Hee-Ran, ''Asymmetric Passive Components in Microwave Integrated Circuits'', John Wiley & Sons, 2006 {{ISBN|0470036958}}.

* Albanese, V J; Peyser, W P, [https://ieeexplore.ieee.org/document/1125207/ "An analysis of a broad-band coaxial hybrid ring"], ''IRE Transactions on Microwave Theory and Techniques'', vol. 6, iss. 4, pp.&nbsp;369–373, October 1958.

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* Garg, Ramesh; Bahl, Inder; Bozzi, Maurizio, ''Microstrip Lines and Slotlines'', Artech House, 2013 {{ISBN|1608075354}}.

* Ghione, Giovanni; Pirola, Marco, ''Microwave Electronics'', Cambridge University Press, 2017 {{ISBN|1107170273}}.

* Grieg, D D; Englemann, H F, [https://doi.org/10.1109/JRPROC.1952.274144 "Microstrip&nbsp;– aMicrostrip—a new transmission technique for the kilomegacycle range"], ''Proceedings of the IRE'', vol. 40, iss. 12, pp.&nbsp;1644–1650, December 1952.

* Gupta, S K, ''Electro Magnetic Field Theory'', Krishna Prakashan Media, 2010 {{ISBN|8187224754}}.

* Harrel, Bobby, ''The Cable Television Technical Handbook'', Artech House, 1985 {{ISBN|0890061572}}.

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* Janković, Nikolina; Zemlyakov, Kiril; Geschke, Riana Helena; Vendik, Irina; Crnojević-Bengin, Vesna, "Fractal-based multi-band microstrip filters", ch. 6 in, Crnojević-Bengin, Vesna (ed), ''Advances in Multi-Band Microstrip Filters'', Cambridge University Press, 2015 {{ISBN|1107081971}}.

* Johnson, Robert A, ''Mechanical Filters in Electronics'', John Wiley & Sons Australia, 1983 {{ISBN|0471089192}}.

* Johnson, Robert A; Börner, Manfred; Konno, Masashi, [https://doi.org/10.1109/T-SU.1971.29611 "Mechanical filters&nbsp;– afilters—a review of progress"], ''IEEE Transactions on Sonics and Ultrasonics'', vol. 18, iss. 3, pp.&nbsp;155–170, July 1971.

* Kumar, Narendra; Grebennikov, Andrei, ''Distributed Power Amplifiers for RF and Microwave Communications'', Artech House, 2015 {{ISBN|1608078329}}.

* Lacomme, Philippe; Marchais, Jean-Claude; Hardange, Jean-Philippe; Normant, Eric, ''Air and Spaceborne Radar Systems'', William Andrew, 2001 {{ISBN|0815516134}}.