Integrating Resonator to Enhance Magnetometer Microelectromechanical System Implementation with ASIC Compatible CMOS...

Area of Science:

• Microelectromechanical Systems (MEMS)
• Sensor Technology
• Magnetometry

Background:

• Traditional magnetometers often require external components like clocks and current generators, increasing system complexity and size.
• Achieving a large dynamic range and high resolution simultaneously in magnetic field sensors presents a significant challenge.

Purpose of the Study:

• To develop a multi-function microelectromechanical system (MEMS) magnetometer with an integrated MEMS oscillator.
• To enhance the magnetometer's dynamic range and sensitivity by utilizing resonant frequency characteristics.
• To reduce noise and improve resolution through advanced readout circuitry and calibration techniques.

Main Methods:

• Integration of a MEMS oscillator with a magnetometer to leverage resonant frequency for Lorentz current generation.
• Adjustment of resonant frequency via bias voltage to tune magnetometer sensitivity.
• Utilization of nested chopper and correlated double-sampling (CDS) readout circuits for noise reduction.
• Implementation of a calibration circuit to compensate for manufacturing process errors.

Main Results:

• The proposed magnetometer exhibits a frequency tuning range of 17,720–19,924 Hz and a measurement tuning range of 110,620.36 ppm.
• Sensitivities for x-, y-, and z-axes are 218.3, 74.33, and 7.5 μV/μT, respectively, at a 2 mA driving current.
• Resolutions for x-, y-, and z-axes are 3.302, 9.69, and 96 nT/√Hz, respectively, demonstrating high precision.

Conclusions:

• The integrated MEMS magnetometer offers a large dynamic range and high sensitivity by using resonant frequency oscillation.
• The advanced readout and calibration circuits effectively reduce noise and compensate for errors, leading to improved measurement resolution.
• This novel MEMS magnetometer design presents a compact and efficient solution for precise magnetic field sensing.