Flexible-Printed-Circuits Based Magnetizing Coil for a High-Frequency and Large-Amplitude Magnetic-Field Generator

This paper proposes a magnetic field generator having a capability of high-frequency and large-amplitude for magnetic material evaluation. A small-area and short-time are enough to evaluate magnetic materials under such the condition. The proposed a magnetic field generator consists of a high-frequency full-bridge inverter and a solenoid with special structure proposed in this paper. The solenoid proposed in this paper has suitable structure for series resonant using flexible-printed-circuits (FPCs). The resonant capacitors in the proposed solenoid are spirally arranged on the outer circumference of the FPCs used for the solenoid. A 60-turn solenoid prototype based on the proposed structure is fabricated and tested with a full-bridge inverter operating at 4 MHz. The prototype can generate a large high-frequency current of 47 A that is enough to generate magnetic field having 350 kA/m (0.44 T). As a result, the proposed solenoid structure exhibits good capability of generating a high-frequency and large-amplitude magnetic field.