(1. 中南大学 有色金属成矿预测教育部重点实验室，长沙 410083；
2. 中南大学 地球科学与信息物理学院，长沙410083；3. 长沙五维地科勘察技术有限责任公司，长沙 410205)
摘 要: 感应式磁场传感器一直是我国电磁法仪器发展的瓶颈，国外大地电磁法中测量大地磁场主要采用感应式磁场传感器。为此，根据音频大地电磁场源的特点，从感应式磁场传感器的基本原理出发，设计传感器的磁芯和线圈绕组结构以及线圈的谐振频率；另外，采用了磁通负反馈技术和频率补偿的方法，扩展了传感器的频带，得到了在1 Hz~9.8 kHz频带范围内平坦度为±1.5 dB的灵敏度曲线，满足音频大地电磁探测的需要。
关键字: 音频大地电磁；感应式磁场传感器；灵敏度；磁通负反馈
audio-frequency magnetotelluric sounding
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
3. Changsha 5D Geo-survey & Technical Co., Ltd., Changsha 410205, China）
Abstract:Magnetic field induction sensors have been the bottleneck in the development of electromagnetic devices in China. In abroad, the natural geomagnetic variations are mainly measured by magnetic field induction sensors in magnetotelluric methods. According to the characteristics of the natural geomagnetic variations in audio-frequency band and the basic principle of magnetic field induction sensors, the structure of core, coil winding and the resonant frequency of the sensor were designed. With the magnetic flux negative feedback and frequency compensation, the frequency band is extended and the flat resulting amplitude-frequency response is obtained in the frequency band of 1 Hz−9.8 kHz with the deviation no more than ±1.5 dB. It can be used in audio-frequency magnetotelluric sounding.
Key words: audio-frequency magnetotelluric sounding method; magnetic field induction sensor; sensitivity; magnetic flux negative feedback
