Compact Magnetic Field Amplification by Tuned Lenz Lens

Abstract

High-frequency magnetic field sensing is a vital feature of several biomedical and industrial applications. Typically, highly sensitive magnetic materials are used for such applications, yet such materials are expensive and their development is bespoke. Recently, there has been an increased interest in reshaping magnetic fields to enhance the high performance of sensing devices. In this article, we present and evaluate the design of a Lenz lens (LL)-based miniaturized magnetic field sensor onto a single substrate. We envision that our device can be used for magnetic field-based sensing applications. Through simulations, we show that the introduction of LL confines and enhances the magnetic field in the region of the sensor. Our design is validated using laboratory measurements that show a 40-fold improvement in the detected signal at 28.6 MHz when an LL is placed around the sensor. We also note that the enhancement leads to a 15-dB increase in the signal-to-noise ratio (SNR) of the detected signal. We fabricated the design using etching techniques that are both well-known and low-cost, therefore, showing potential for mass-scale production. We demonstrate that it is not only possible to create a device that enhances magnetic field sensitivity but also to do so in a manner that makes it easy to integrate with existing technologies. The latter feature allows it to become immediately useful for a variety of nuclear magnetic resonance (NMR) applications.