Distributed-element circuit: Difference between revisions

Revision as of 11:33, 20 August 2019

Revision as of 11:33, 20 August 2019

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{{see also|Fractal antenna}}

[[file: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.'', ppp. 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>

Fractals that have been used as a circuit component include the [[Koch snowflake]], [[Minkowski island]], [[Sierpiński curve]], [[Hilbert curve]], and [[Peano curve]].<ref>Janković ''et al.'', p. 196</ref> The first three are closed curves, suitable for patch antennae. The latter two are open curves with terminations on opposite sides of the fractal. This makes them suitable for use where a connection in [[cascade connection|cascade]] is required.<ref>Janković ''et al.'', p. 196</ref>