Loop-gap resonator

<p>A loop-gap resonator (LGR) is an electromagnetic resonator that operates in the radio and microwave frequency ranges. The simplest LGRs are made from a conducting tube with a narrow slit cut along its length. The LGR dimensions are typically much smaller than the free-space wavelength of the <a href="/facts/Electromagnetic_field/MacraS8y">electromagnetic fields</a> at the resonant frequency. Therefore, relatively compact LGRs can be designed to operate at frequencies that are too low to be accessed using, for example, <a href="/facts/Microwave_cavity/WY23zCqz">cavity resonators</a>. These structures can have very sharp resonances (high <a href="/facts/Quality_factor/NNjGLb5b">quality factors</a>) making them useful for <a href="/facts/Electron_spin_resonance/TDHV8c9e">electron spin resonance</a> (ESR) experiments, and precision measurements of electromagnetic material properties (<a href="/facts/Permittivity/Sd3WtgT1">permittivity</a> and <a href="/facts/Permeability_(electromagnetism)/GA7CcRLU">permeability</a>).
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Loop-gap resonator open-in-new

Loop-gap resonator