低噪声宽带宽感应式磁传感器  

Low noise wideband inductive magnetic sensor

作　　者：尚新磊[1,2] 王琳[2] 林君[1,2] 符磊[1] 王晓光[1] 陈晨[1,2] 

机构地区：[1]吉林大学仪器科学与电气工程学院,吉林长春130026 [2]吉林大学地球信息探测仪器教育部重点实验室,吉林长春130026

出　　处：《中南大学学报（自然科学版）》2015年第9期3295-3301,共7页Journal of Central South University:Science and Technology

基　　金：基金项目国家重大科学仪器开发专项(2011YQ30133);国家高技术研究发展计划(863计划)项目(2013AA063904)~~

摘　　要：在大深度测量时,由于传统空心线圈传感器自身空心线圈和差分放大器部分引入了噪声,致使感应式磁传感器探测灵敏度降低,无法满足地质探测深度的需要。针对此问题,通过理论分析空心线圈磁传感器中空心线圈的物理结构和前置放大电路的机理,研究引入噪声的主要来源,建立基于结型场效应晶体管(JFET)的感应式磁传感器等效模型,提出一种低噪声宽带宽空心线圈磁传感器。同时,分析该模型下差分放大器的频域特性,给出磁传感器输入噪声的仿真结果。在屏蔽室内和野外试验对所研制的磁传感器性能进行测试。研究结果表明:该磁传感器的3 d B响应带宽达到42.3 k Hz,相比于磁传感器3D-3响应带宽增加了1倍。在输入噪声水平方面,其输入噪声在频率为10 k Hz时为1.97 n V/Hz1/2,较磁传感器3D-3信噪比提高了10.04 d B,为感应式磁传感器在实际项目应用提供了可靠的性能保障。Noise is introduced by air-core coil and differential amplifier of traditional air-core coil sensor in large depth measurement applications, the detection sensitivity of inductive magnetic sensor is reduced, which is unable to meet the requirement of geological exploration depth. For the aforementioned problem, through the theoretical analysis for the air-core coil physical structure of magnetic sensor and the mechanism of the pre-amplifier circuit, the primary noise sources were studied, the equivalent model of induction magnetic sensor based on junction field effect transistor（JFET） was built, and a low noise wide bandwidth air-core coil magnetic sensor was proposed finally. Meanwhile, the differential amplifier characteristics were analyzed using the proposed model in frequency domain, and the simulation results of input noise of the magnetic sensor were given. The performance of the developed magnetic sensor was verified in shielding room. The results show that the 3 d B bandwidth of magnetic sensor is 42.3 k Hz, which is doubled compared with that of the traditional magnetic sensor 3D-3. In addition, the input noise is 1.97 n V/Hz1/2 at the frequency of 10 k Hz, and the signal-to-noise ratio compared with magnetic sensor 3D-3 is increased by 10.04 d B, which guarantees performance for inductive magnetic sensor in real application.

关 键 词：大深度测量 空心线圈磁传感器 结型场效应晶体管 低噪声 带宽 

分 类 号：TP212.1[自动化与计算机技术—检测技术与自动化装置]