Vector Magnetic Field Sensing Based on Ultrasimple Structure of YIG Resonator

Magnetic field measurement sensing techniques have a wide range of applications in scientific research and industrial production. The whispering gallery mode (WGM) resonators, known for their ultra-high-quality factor (Q), offer exceptional resolution for high-precision magnetic field sensing. However, since most resonator materials are inherently insensitive to magnetic fields, they need to be combined with magnetically sensitive materials to form complex sensing structures. This paper proposed an ultrasimple structure that directly utilized an yttrium iron garnet (YIG) resonator as the magnetic field sensing unit. Based on the magnetostrictive effect, the YIG resonator was stretched in the parallel magnetic field direction and contracted in the vertical direction. High sensitivity magnetic field measurement was achieved by detecting the resonance frequency drift caused by resonator deformation. The experimental results showed that the direct current (DC) magnetic field had sensitivity of 14.81 MHz/mT in the range of 2 mT–7 mT, and the peak alternating current (AC) magnetic field sensitivity was 8.6 nT/Hz^1/2 at 774 kHz, with the depth of the concavity of 23.4 dB in the scaling factor direction curve. The sensing device offers the advantages of an ultrasimple structure and high sensitivity, making it highly promising for a wide range of applications.