Distributed-element circuit: Difference between revisions

Revision as of 00:51, 24 October 2019

Revision as of 03:46, 24 October 2019

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{{Short description|Electrical circuits composed of lengths of transmission lines or other distributed components}}

[[File:LNB circuit.jpg|thumb|upright=1.5|alt=Satellite-TV block-converter circuit board|A [[low-noise block converter]] with distributed elements. The circuitry on the right is [[lumped element]]s. The distributed-element circuitry is centre and left of centre, and is constructed in [[microstrip]].]]

'''Distributed-element circuits''' are electrical circuits composed of lengths of [[transmission line]]s or other distributed components. These circuits perform the same functions as conventional circuits composed of [[Passivity (engineering)|passive]] components, such as [[capacitor]]s, [[inductor]]s, and [[transformer]]s. They are used mostly at [[microwave]] frequencies, where conventional components are difficult (or impossible) to [[Www.ndtv.com|implement]].

Conventional circuits consist of individual components manufactured separately then connected together with a conducting medium. Distributed-element circuits are built by forming the medium itself into specific patterns. A major advantage of distributed-element circuits is that they can be produced cheaply as a [[printed circuit board]] for consumer products, such as [[satellite television]]. They are also made in [[coaxial cable|coaxial]] and [[waveguide (electromagnetism)|waveguide]] formats for applications such as [[radar]], [[satellite communication]], and [[microwave link]]s.

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=== Fractals ===

{{see also|Fractal antenna}}

[[fileFile:Hilbert resonator.svg|thumb|upright|alt=diagram|Three-iteration Hilbert fractal resonator in microstrip<ref>Janković ''et al.'', p. 197</ref>]]

The use of [[fractal]] curves as a circuit component is an emerging field in distributed-element circuits.<ref>Ramadan ''et al.'', p. 237</ref> Fractals have been used to make resonators for filters and antennae. One of the benefits of using fractals is their space-filling property, making them smaller than other designs.<ref>Janković ''et al.'', p. 191</ref> Other advantages include the ability to produce [[wide-band]] and [[Multi-band device|multi-band]] designs, good in-band performance, and good [[out-of-band]] rejection.<ref>Janković ''et al.'', pp. 191–192</ref> In practice, a true fractal cannot be made because at each [[Iterated function system|fractal iteration]] the manufacturing tolerances become tighter and are eventually greater than the construction method can achieve. However, after a small number of iterations, the performance is close to that of a true fractal. These may be called ''pre-fractals'' or ''finite-order fractals'' where it is necessary to distinguish from a true fractal.<ref>Janković ''et al.'', p. 196</ref>