Distribution measurement of permittivity by dividing the sample into multisection in the slotted cylindrical cavity

Abstract There are few papers to introduce the distribution measurement of material’s permittivity in the previous work, but the measurement is an important effort to effectively evaluate the inhomogeneity of material’s permittivity. In order to measure the distribution of the relative permittivity with small interval along sample rod, a multisection measurement model has been introduced. The sample is horizontally inserted into the slotted cylindrical cavity with TM 0 n 0 working modes and passes through it to improve the measurement stability. During the measurement, the sample is divided into many sections, and each section is treated as a subsample for the distribution measurement of the permittivity. The traditional perturbation technology is combined with the field analysis of two subsamples in the cavity to calculate the permittivity of all subsamples from the effective permittivity. Based on the theoretical analysis of the simulation results from HFSS, partial error equation is established, and the absolute error of the multisection measurement model is less than 0.1. Besides, the horizontal movement device for the sample movement, support platform with a groove for the sample placement, and vertical cylindrical cavity for the measurement are employed to make up the test setup. Meanwhile, it can provide a stable and rapid measurement. Thus, a fiber reinforced plastic rod has been measured to verify the feasibility of the developed test setup.