Interdigital converter

Input and output converters in a SAW device

Converters in a real device on a SAW

The interdigital transducer , IDT ^[1] , also the interdigital transducer is a device consisting of two interconnected comb-shaped metal coatings (like a zipper) that are used on a piezoelectric substrate made of quartz , lithium niobate and lithium tantalate , and also a number of other oriented single crystals .

Used to convert electromagnetic waves to surface acoustic waves (SAWs). Devices based on surface acoustic waves are mainly used in electronics. The most common devices for surface acoustic waves are resonators and filters . Depending on the geometric application (IDT), the output of the devices will vary.

If the IDT has a period p , then the center frequency is

${\displaystyle {\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">\omega </span></span>}}_{\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">c</span></span>}}<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">=</span></span>\frac{\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">2</span></span>}\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">\pi </span></span>}{\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">v</span></span>}}_{\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">0</span></span>}}}{\mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">p</span></span>}}<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">,</span></span>}${\ displaystyle \ omega _ {c} = {\ frac {2 \ pi v_ {0}} {p}},}

where v ₀ is the wave velocity under the IDT ^[2] .