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Quadrupole Mass Spectrometer
The principle component of a quadrupole mass spectrometer is the mass filter which is used to filter ions with different charge to mass ratios. The quadrupole mass filter has been well studied over the years, Ref. 1 and the physics and optimal design are well understood. In a real quadrupole mass spectrometer, fringe fields exist at both the entrance and exit of the mass filter. These fringe ...
Comparison of Effective HB/BH Curve with Linear and Nonlinear Material Models
This example illustrates how to setup the Effective HB/BH Curve material model, introduced in COMSOL 5.2, for modeling the magnetic materials in frequency domain. The model also compares the results from Effective HB/BH Curve model with the linear and nonlinear HB/BH Curve material model in 2D.
Touchscreen Simulator
Intended as a tool for early proof of concept in capacitive touchscreen device development, the Touchscreen Simulator app evaluates a simulated capacitance matrix as well as the electric field norm. The app computes the capacitance matrix of a touchscreen in the presence of a human finger phantom, where the position and orientation of the finger are controlled via input parameters. This ...
External Material, AC/DC Module, General HB/BH relation
The AC/DC magnetic interfaces now support material models defined in external C code. A new way to specify user-defined material models is included in COMSOL Multiphysics version 5.2. You can now access external material functions, written in C code, which have been compiled into a shared library. By writing a wrapper function in C code, you can also use material functions written in another ...
Iron Sphere in a 60 Hz Magnetic Field
An iron sphere is exposed to a spatially uniform, sinusoidally time-varying, background magnetic field. The frequency of the field is low enough such that the skin depth is larger than the radius of the sphere. A reduced field formulation is used to impose the background field. Two approaches for solving this problem are shown. The induced currents in the sphere and the perturbation to the ...
An RFID System
RFIDs are used in a multitude of applications such as tracking or identifying consumer products and their packaging. An RFID system consists of two main parts: A tag or transponder with a printed circuit-board (PCB) antenna A reader unit with a larger RF antennaThe reader antenna generates an electromagnetic field that energizes a chip (IC-circuit) inside the tag. The electromagnetic field ...
Simulation of RF Tissue Ablation
This example exemplifies how to model tissue ablation through applying RF radiation. A more detailed description of the phenomenon, and the modeling process, can be seen in the blog post "[Study Radiofrequency Tissue Ablation Using Simulation](https://www.comsol.com/blogs/study-radiofrequency-tissue-ablation-using-simulation/)".
Magnetically Permeable Sphere in a Static Magnetic Field
A sphere of relative permeability greater than unity is exposed to a spatially uniform static background magnetic field. Two formulations are used to solve this problem, and the differences between these are discussed. The field strength inside the sphere is computed and compared against the analytic solution.
Computing Intercepted Flux
This example model demonstrates four different approaches for computing the integrals of fields over arbitrarily placed geometries that can be re-positioned without having to re-solve the model. This approach is also useful if you want to integrate the results of a model over different sub-regions that you do not want to include in your original computational model. The example of computing ...
Axial Field Magnetic Gear in 3D
In this model, an axial field magnetic gear with a gear ratio of 5:2 is modeled. Both the high speed and low speed rotors consist of permanent magnet and back iron. The low speed rotor consists of five pole-pairs, while the high speed rotor consists of two pole pairs, and the stationary steel consists of seven pole-pairs. The *Rotating Machinery, Magnetic* interface is used to evaluate the ...
