Temperature Correction Using Degenerate Modes for Cylindrical Cavity Perturbation Measurements - dataset

Microwave cavity perturbation measurements are a useful way to analyse material properties. Temperature changes can be introduced during these measurements either intentionally or as a result of some other process. The microwave cavity itself also has a temperature dependent response which can affect the results. A common method to correct for this is to use another resonant mode separate to the measurement mode which is not affected by the sample. Instead of using independent modes this paper describes a method to use split degenerate TM_m10 modes. TM_m10 consists of two modes with identical field patterns with a relative rotation between them and identical resonant frequencies. A strategically placed perturbation reduces the frequency of one of the TM_m10 modes and affects the coupling of both modes by reconfiguring the fields. This can be used for temperature correction by placing a sample such that both modes are equally coupled. The lower frequency perturbed mode is used as a measurement mode. The higher mode is used as a reference for temperature correction as it is unaffected by the sample. This technique was verified by measuring the permittivity of pure water using an aluminium microwave cavity resonator at 3.98 GHz. The temperature was swept between 20 ºC and 60 ºC and the results verified against the literature.

Research results based upon these data are published at http://doi.org/10.1109/TMTT.2018.2882480