Dielectric resonator in rectangular ТЕ102 cavity for electron paramagnetic resonance study of thin films

•Suitable geometry of dielectric resonator (DR) for thin films study was calculated.•DR was fabricated from BaTi4O9 + 8.5% ZnO ceramics (ε=36).•Application of DR increases filling factor by 5–12 times depending on films sizes.•EPR signal increase by ∼4 times was experimentally obtained for SiOx 950 nm film. The improved compared to a rectangular TE102 cavity geometry of a dielectric resonator (DR) suitable for studying thin films and coatings has been calculated and experimentally verified. It is shown that electron paramagnetic resonance (EPR) signal of SiOx films can be enhanced by using as the DR of two rectangular parallelepipeds fabricated from BaTi4O9 + 8.5% ZnO ceramics (ε=36) with dimension of 5.64×5.5 × 5.9 mm3 and a gap of up to 0.5 mm between them. Located inside a standard rectangular metal TE102 cavity of the X-band EPR spectrometer, the DR increases the filling factor by 5–12 times depending on the size of a sample studied. The experimental use of the DR allows to increase the EPR signal of the 950 nm SiOx thin film by a factor of approximately 4.