Distributed-element circuit: Difference between revisions

Revision as of 15:36, 8 August 2019

Revision as of 16:54, 9 August 2019

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'''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 implement.

Conventional circuits consist of individual components manufactured separately then connected together with a conducting medium. Distributed element circuits consist of forming the medium itself into certain 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.

A phenomenon commonly used in distributed element circuits is that a length of transmission line can be made to behave as a [[resonator]]. Distributed element components which do this include [[stub (electronics)|stubs]], [[coupling (physics)|coupled lines]], and cascaded lines. Circuits built from these components include [[distributed element filter|filters]], [[power dividers and directional couplers|power dividers, directional couplers]], and [[circulator]]s.

Distributed element circuits were studied during the 1920s and 1930s but did not become important until [[World War II]], when they were used in [[radar]]. After the war their use was limited to military, space, and [[broadcasting]] infrastructure, but improvements in [[materials science]] in the field soon led to broader applications.

[[File:Lumped-distributed comparison.png|thumb|upright=2|A low-pass filter as conventional discrete components connected on a [[printed circuit board]] (left), and as a distributed element design printed on the board itself (right)]]

== Circuit modelling ==