## High-Fidelity Modeling of a Tunable Filter via Multiphysics Simulation

##### Jiyoun Munn April 3, 2018

Since high-speed communication is inevitable for evolving wireless systems, the demand for a higher data rate, higher frequency, larger spectrum, and wider bandwidth increases. When dealing with a wide bandwidth, multiple devices may have to be deployed in a wireless communication system to filter out unwanted noise and interfering signals, enhance the signal-to-noise ratio, and improve the sensitivity. A single tunable filter can replace these devices, reducing the system’s size and weight and the fabrication cost of multiple components.

Read More##### Friedrich Maier March 30, 2018

Sweeps are very useful for characterizing a system and learning more about how different input values impact the results. You can perform several different types of sweeps in the COMSOL Multiphysics® software, including function, material, and parametric sweeps. However, precise and innovative simulation results also call for mathematical optimization. In this blog post, learn how to combine sweep studies with the built-in optimization functionality.

Read More##### Amelia Halliday March 29, 2018

When creating a simulation, you usually start by building the forward model, supplying various inputs, and then looking at the results. However, what if you have a set of results and want to find the input values that provide the same outcome? Here, we show how to use the Parameter Estimation study step, which helps you build an inverse model and solve for the optimal values of your model inputs.

Read More##### Ed Fontes March 26, 2018

The algebraic multigrid (AMG) solver provides robust solutions for large CFD simulations. Available as of version 5.3a of the COMSOL Multiphysics® software, the AMG method only requires one mesh, in contrast to the geometric multigrid (GMG) solver, which requires at least one extra coarser mesh. This eliminates the hassle associated with creating coarse meshes for complex geometries with small details that are difficult to mesh unless a fine mesh is used.

Read More##### Hanna Gothäll March 20, 2018

We have already discussed different ways to create geometry objects of irregular shapes on the blog. In this blog post, we will demonstrate an incredibly powerful alternative approach by using interpolation functions. Instead of creating geometry objects, we will indirectly define the irregular shape by taking advantage of the spatial variation of a material property in the object we want to study.

Read More##### Mads Herring Jensen March 19, 2018

The boundary element method (BEM) is included in the Acoustics Module as a physics interface. This interface, available as of version 5.3a of the COMSOL Multiphysics® software, can be seamlessly combined with interfaces based on the finite element method (FEM) to model, for example, acoustic-structure interaction problems. This functionality expands the range of problems that can be solved with the Acoustics Module. Here, we look into the BEM functionality, examples, and BEM-specific postprocessing.

Read More##### Nicolas Huc March 15, 2018

Nonisothermal flow combines CFD and heat transfer analysis. In cases where the temperature of the fluid at an inlet is a known quantity, a Temperature boundary condition can be used. However, there are some important situations where this is not the case, and an Inflow boundary condition can improve the model accuracy and reduce the computational cost of the simulation. Here, we review how this more sophisticated thermal boundary condition can be set at a flow inlet.

Read More##### Lars Drögemüller March 9, 2018

Many types of analyses benefit from running the COMSOL Multiphysics® software on high-performance computing (HPC) hardware. This is one of the main reasons behind the Cluster Computing node, which helps seamlessly integrate the COMSOL® software with any kind of HPC infrastructure, while maintaining the convenience of a graphical user interface. In this blog post, learn how to run large simulations remotely on HPC hardware directly from the COMSOL Desktop® graphical environment.

Read More##### Guest René Christensen February 28, 2018

Today, guest blogger René Christensen of GN Hearing discusses including thermoviscous losses in the topology optimization of microacoustic devices. Topology optimization helps engineers design applications in an optimized manner with respect to certain a priori objectives. Mainly used in structural mechanics, topology optimization is also used for thermal, electromagnetics, and acoustics applications. One physics that was missing from this list until last year is microacoustics. This blog post describes a new method for including thermoviscous losses for microacoustics topology optimization.

Read More##### Prashant Srivastava February 14, 2018

Bearings, specifically rolling element bearings, are some of the most commonly used industrial components. These bearings are found in gearboxes, conveyors, motors, and rolling mills due to the low friction and low starting torque compared to hydrodynamic bearings. They can also handle changes in speed, temperature, and loads. In this blog post, we will look at different bearing types and demonstrate how to model a rotor system supported on roller bearings using the COMSOL Multiphysics® software.

Read More##### Nathan Martin February 8, 2018

In a 2013 report, the Intergovernmental Panel on Climate Change stated that Earth’s cryosphere is “a natural integrator of climate variability and provides some of the most visible signatures of climate change.” (Ref. 1) The cryosphere is the part of the climate system that contains frozen water and makes up 80% of our fresh water. Using the COMSOL Multiphysics® software, we can simulate classical ice flow to analyze cryosphere dynamics and assess climate change effects such as rising sea levels.

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