High-Sensitivity Low-Noise Miniature Fluxgate Magnetometers Using a Flip Chip Conceptual Design

Abstract

This paper presents a novel class of miniature fluxgate magnetometers fabricated on a print circuit board (PCB) substrate and electrically connected to each other similar to the current “flip chip” concept in semiconductor package. This sensor is soldered together by reversely flipping a 5 cm × 3 cm PCB substrate to the other identical one which includes dual magnetic cores, planar pick-up coils, and 3-D excitation coils constructed by planar Cu interconnections patterned on PCB substrates. Principles and analysis of the fluxgate sensor are introduced first, and followed by FEA electromagnetic modeling and simulation for the proposed sensor. Comprehensive characteristic experiments of the miniature fluxgate device exhibit favorable results in terms of sensitivity (or “responsivity” for magnetometers) and field noise spectrum. The sensor is driven and characterized by employing the improved second-harmonic detection technique that enables linear V-B correlation and responsivity verification. In addition, the double magnitude of responsivity measured under very low frequency (1 Hz) magnetic fields is experimentally demonstrated. As a result, the maximum responsivity of 593 V/T occurs at 50 kHz of excitation frequency with the second harmonic wave of excitation; however, the minimum magnetic field noise is found to be 0.05 nT/Hz1/2 at 1 Hz under the same excitation. In comparison with other miniature planar fluxgates published to date, the fluxgate magnetic sensor with flip chip configuration offers advances in both device functionality and fabrication simplicity. More importantly, the novel design can be further extended to a silicon-based micro-fluxgate chip manufactured by emerging CMOS-MEMS technologies, thus enriching its potential range of applications in modern engineering and the consumer electronics market.

Vectorized magnetometer for space applications using electrical readout of atomic scale defects in silicon carbide

“…Sigma-delta ADC technology with improved sampling resolution has been leveraged to enhance sensitivity of this technology2021. Even though significant progress has been made to miniaturize these magnetometers22, the incorporation of a magnetically susceptible core wrapped with driving, sensing, and nulling coils for each axis will always limit the size and weight, and will never lead to a purely electrical device.…”

Novel Giant Magnetoimpedance Magnetic Field Sensor

“…This alloy has significant lower noise spectrum than Co70Fe5Ni2Mo5B3Si15 [46]. Numerous publications describing the use of the Co66Fe4Ni1Si15B14 alloy on the fluxgate [47,48] or induction [49] sensor core have confirmed its excellent noise properties. Figure 3 shows only part of the results to make it legible; the inset of Figure 3 indicates the GMI characteristics in the full area of the magnetizing field.…”

Numerical Analysis of the Informational Parameters of the Magnetic Fields in the Area of the Defects of Wheel Pairs Axes

“…Fluxgate magnetometers are a class of sensitive sensors used to measure direct current or low-frequency magnetic field vectors. Conventional fluxgate sensors typically feature low noise, high sensitivity and excellent accuracy [2,3]. Fluxgate transducers are promising in applications for military detection, inertial navigation, bio-medical identification [4,5] and non-destructive testing [6].…”