A Multigap Loop Antenna and Norm Detector-Based Nano-Second-Level Transient Magnetic-Field Sensor

Based on multigap loop (MGL) antenna and low-noise norm detector, a novel nano-second (ns)-level transient magnetic-field ( {H} -field) sensor is proposed in this article. The direct measurement result of the MGL antenna is the differential signal of the H -field, which is capable to be digitized for storage by the norm detector. The original H -field can be restored using the software integral method. The developed ns-level H -field sensor exhibits two major advantages. First, it can measure the H -field in the substation or the coupled H-field inside the hermetically sealed cavities, such as the cockpit of vehicles or aircrafts, which is because the need for the transmission line is removed. Second, its sensitivity is significantly higher than the measurement system with the hardware passive integrator, and the integral error can also be effectively reduced by the low-noise norm detector. In this article, the realization of the ns-level transient H-field sensor will be detailed. The simulated upper cutoff frequency of the designed MGL antenna is about 1.9 GHz. The sampling rate of the norm detector is 2 GS/s as the maximum. The dynamic range of the detector is about 42 dB and the operation bandwidth ranges from 0.3 kHz to 500 MHz by calibration. The total storage space of 128 kB can record as long as 64μs at 2 GS/s and is extendable. Test results show that the developed sensor can measure the ns-level H -field accurately.