This research has been supported by European Union's Horizon 2020 programme FET-OPEN project PETER, GA 767 227. The Center for Integrated Quantum Science and Technology (IQST), and the Carl Zeiss Foundation are also acknowledged. The authors thank Brno University of Technology (FSI-S-20-6485) and the GAČR project 20–28573S. The authors acknowledge financial support from the Spanish Ministry of Science, Innovation and Universities (national project RTI2018-094830-B-100 and the project MDM-2016-0618 of the Maria de Maeztu Units of Excellence Program) and the Basque Government (grant No. IT1164-19). The authors thank Prof. Sabine Ludwigs and David Neusser for access to the SnowJet cleaner. The authors thank Thomas Keating Ltd. for providing the quasi-optical bench used for the transmission measurements of the PMR. The authors thank Dennis Schäfter for the valuable support provided for the Python scripts and Martin Konečný for useful discussions. Open access funding enabled and organized by Projekt DEAL.

This dataset contains the raw experimental data for Tesi et al., Plasmonic Metasurface Resonators to Enhance Terahertz Magnetic Fields for High-Frequency Electron Paramagnetic Resonance, Small Methods 2021, 2100376, DOI 10.1002/smtd.202100376.