Magnetic field strength improvement for Lorentz actuation of a μ-Coriolis mass flow sensor

In this paper we present and compare three different magnet configurations for Lorentz actuation of a μ-Coriolis mass flow sensor. The first configuration consists of 2 cylindrical magnets, the second is based on a Halbach ring, and the third configuration consists of a single cubic magnet. The magnetic field strength of each configuration is simulated. The Halbach configuration shows a magnetic field strength of 0.3 T, the single cubic configuration reaches 0.25 T. The two cylindrical magnets have the lowest field with 0.05 T. The stray field is significantly lower for the Halbach configurations compared to the other two configurations. All configurations were used for Lorentz actuation of a μ-Coriolis mass flow sensor and the frequency response was measured. The magnitude transfer between the actuation and induction voltages for the cubic and Halbach configurations show a transfer around 26 dB higher than the cylindrical configuration. The phase transfers for the Halbach and Cubical configurations are according to simulation. For the cylindrical configuration, the EMF signal is too weak to overcome the crosstalk between the actuation and induction voltages.