How to Perform a Nonlinear Distortion Analysis of a Loudspeaker Driver

Kirill Shaposhnikov June 18, 2018

A thorough analysis of a loudspeaker driver is not limited to a frequency-domain study. Some desirable and undesirable (but nonetheless exciting) effects can only be caught by a nonlinear time-domain study. Here, we will discuss how system nonlinearities affect the generated sound and how to use the COMSOL Multiphysics® software to perform a nonlinear distortion analysis of a loudspeaker driver.

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Thomas Forrister June 5, 2018

The greenhouse effect has made it necessary for scientists to develop combustion processes that minimize the accumulation of carbon dioxide in the atmosphere. Possible fuels in these processes include biomass and other biofuels, which recycle carbon within a short timescale. But there’s a downside: Combustion of these materials produces carbon and ash particles that must be removed from the exhaust. To improve particle filtration, researchers studied electrostatic filter designs using models that were validated by comparing them to experimental data.

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Walter Frei May 25, 2018

One of the more common uses of the AC/DC Module, an add-on to the COMSOL Multiphysics® software, is for modeling conductors and other lossy materials in time-varying magnetic fields when there are significant induced currents. The appropriate modeling approach depends upon how quickly the magnetic fields vary over time. Here, we review the basics and describe various modeling techniques to use.

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Caty Fairclough May 17, 2018

Mount Erebus, one of Earth’s most remote volcanoes, sits covered in snow and ice. These chilly surroundings can be misleading, as Mount Erebus has another claim to fame: It’s the most active volcano in Antarctica. One option for mapping its magma flow is with a technique called magnetotellurics (MT), which measures the electrical resistivity of Earth’s crust. To study and improve MT, engineers can analyze its performance with electromagnetics simulation.

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Bridget Paulus May 16, 2018

Thanks to their ability to “tune out” specific frequencies, electromagnetic band gaps (EBGs) are found in many different applications. EBGs can suppress unwanted electromagnetic interference (EMI) and increase electromagnetic compatibility (EMC). These structures are commonly used between nearby antennas, which can help minimize undesirable coupling and thereby enhance their performance. However, using an EBG isn’t always a guarantee for better antenna isolation. To analyze the effectiveness of an EBG, engineers can use the COMSOL Multiphysics® software and add-on RF Module.

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Brianne Costa May 9, 2018

During his life, John Scott Russell chased his passion for science — literally. While watching horses pull a boat through a shallow canal, he noticed a wave behaving strangely and followed it for one or two miles on horseback. For the rest of his life, he continued to chase this wave (which he called the “wave of translation”) figuratively, persevering even when his theories were ridiculed by scientists. Did Scott Russell ever catch up to his wave?

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Stuart Barnes May 7, 2018

The Ray Optics Module extends the modeling capabilities of the COMSOL Multiphysics® software to include ray tracing simulation. This module makes it possible to accomplish advanced thermal, structural, and other studies of complex optical systems in an integrated software environment. The first step in a successful simulation is the creation of the model geometry. This blog post examines how to create a complex lens geometry, using the Petzval lens as an example.

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Thomas Forrister May 3, 2018

Many antennas deployed in basic communications systems are linearly polarized, meaning that for the orientation of the electric field, polarization is confined to a single plane. Antennas that present the option of circular polarization give you more to work with, because the polarization of the wave varies while it propagates. Helical antennas, for instance, are able to generate circularly polarized waves in the axial operating mode. RF simulation can be used to optimize helical antenna designs.

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Christopher Boucher April 20, 2018

Attitude detection, the measurement of an object’s orientation and rotation in three-dimensional space, is a crucial element in aircraft and spacecraft navigation. Recently, ring laser gyroscopes and fiber ring gyroscopes have proven to be viable alternatives to traditional mechanical gyros for accurately measuring rotations. The fundamental operating principle of such devices is an optical phenomenon called the Sagnac effect. In this blog post, we’ll employ ray optics simulation to observe this effect in a basic Sagnac interferometer.

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Brianne Costa April 19, 2018

When it comes to advancements in healthcare, we have a lot to be thankful for. Because of anesthesia, patients no longer need to “bite the bullet” during surgery. Thanks to antibiotics, doctors don’t use bloodletting to cure an infection. Moving into more modern times, radio-frequency identification (RFID) systems offer a wide variety of innovative healthcare applications. However, like any new medical technology, biomedical RFID devices must be rigorously evaluated for performance and compatibility with other medical systems.

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Walter Frei April 17, 2018

In applications such as power transfer and consumer electronics, it may be critical to model electromagnetic heating of materials that are nonlinear in temperature; that is, the material’s electrical conductivity and thermal conductivity vary with temperature. When modeling these nonlinearities, even an experienced analyst can sometimes get quite unexpected results due to the combination of the nonlinear material properties, boundary conditions, and geometry. Let’s find out why this is in terms of a very simple example.

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