Mechanical antennas with rotating permanent magnets are a relatively new type of transmitting antenna in low- and ultralow-frequency (LF/ULF) ranges. The perspectives of the applications are encouraging, especially in the field of non-destructive defectoscopy and communications through conductive media (underwater communications), which is reflected in the articles published in the last decade. This article describes the experimental setup, results, harmonic analysis, and simulation validation for two configurations of mechanical antennas with rotating NdFeB permanent magnets. The emphasis is placed on the known analytical equations, specifically on the matching of the measurement results with the analytical data as well as with the results given by the numerical analysis. Also, several means of measurement are used to validate the results through replicate testing. Through analytical analysis and the performed measurement, this article establishes the basics for designing mechanical antennas with rotating permanent magnets for the considered configurations based on a single static magnetic field measurement. Finally, we explore prospects for future research in this domain as well as the advantages and disadvantages compared to other types of LF/ULF antennas.

This work analyzes the functional conditions for a high-temperature superconductor (HTS) current limiter model. Introducing a superconducting fault current limiter (SFCL) in a distribution network considerably reduces the overcurrent that occurs due to a fault in the system. The analyzed SFCL conceptual model refers to a resistive limiter model, which operates on the principle of the transition of the superconducting material from the superconducting state to the resistive state when one of the critical parameters of the superconducting state is exceeded, such as the critical current (Ic). Thus, with the occurrence of a fault current for I > Ic, the superconductor goes into a resistive state (phenomenon called "quench") and the current will be diverted to an alternative resistive circuit. The parameters of the quench are analyzed for different current values (50, 100, 200, and 300 A) to determine the protection sizing and operation of an SFCL. They are investigated through numerical simulations with Comsol Multiphysics.