Distributed-element circuit: Difference between revisions

Revision as of 06:45, 1 October 2020

Revision as of 00:06, 27 October 2020

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=== Waveguide ===

{{main|waveguideWaveguide (electromagnetism)}}

[[File:Waveguide-post-filter.JPG|thumb|alt=Rectangular waveguide filter with five tuning screws|A [[waveguide filter]]]]

Many distributed-element designs can be directly implemented in waveguide. However, there is an additional complication with waveguides in that multiple [[waveguide mode|modes]] are possible. These sometimes exist simultaneously, and this situation has no analogy in conducting lines. Waveguides have the advantages of lower loss and higher quality [[resonator]]s over conducting lines, but their relative expense and bulk means that microstrip is often preferred. Waveguide mostly finds uses in high-end products, such as high-power military radars and the upper microwave bands (where planar formats are too lossy). Waveguide becomes bulkier with lower frequency, which militates against its use on the lower bands.<ref>Ghione & Pirola, p. 18</ref>

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=== Dielectric resonator ===

{{main|dielectricDielectric resonator}}

A dielectric resonator is a piece of dielectric material exposed to electromagnetic waves. It is most often in the form of a cylinder or thick disc. Although cavity resonators can be filled with dielectric, the essential difference is that in cavity resonators the electromagnetic field is entirely contained within the cavity walls. A dielectric resonator has some field in the surrounding space. This can lead to undesirable coupling with other components. The major advantage of dielectric resonators is that they are considerably smaller than the equivalent air-filled cavity.<ref>Penn & Alford, pp. 524–530</ref>

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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)|attenuator]]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, Aa card of microwave absorbent material can be inserted into the waveguide.<ref>Hilty, pp. 426–427</ref>

== Circuit blocks ==