The split cylinder resonator consists of two halves of a cylindrical cavity that face each other to form one complete cylindrical cavity resonator. One measures the permittivity just as in the other cases, by simply inserting a sample into the narrow slit between the two halves of the cavity. The sample must be held securely to avoid air gaps that can affect the accuracy of the measurement.

Figure 1: Schematic diagram of a split cylinder resonator. The split cylinder resonator is simply two metal cylinders cut in the middle to allow for a sample (green).


  • New solutions available have solved some of the sample fixturing issues, making cavity-based measurement far more reproducible and user-friendly.


  • In common with all resonator-based techniques, the perturbation cannot be too large because it can change the mode structure. This requirement places limits on the loss tangent and permittivity to values typically less than 0.01 and 30, respectively.

As part of the 5G/6G MAESTRO project, work on this page is supported by the Office of Advanced Manufacturing in the National Institute of Standards and Technology (NIST), under the Federal Award ID Number 70NANB22H050.

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