## Predict Thermal Drift in Microwave Filters Using Multiphysics Simulation

##### Caty Fairclough April 11, 2017

Microwave filters can help prevent unwanted frequency components in the output of a microwave transmitter design. However, when the microwave system experiences thermal drift, it can be difficult to achieve high-frequency stability in the filters. To address this issue and improve filter designs, system engineers need to predict the change of the passband frequency caused by thermal expansion. As we’ll see today, one way to achieve this is with multiphysics modeling.

### 3 Ways to Optimize the Current in Electromagnetic Coils

##### Walter Frei April 10, 2017

If you design electromagnetic coils, the combination of the AC/DC and Optimization modules with the COMSOL Multiphysics® software gives you the power to quickly come up with improved design iterations. Today, we will look at designing a coil system to achieve a desired magnetic field distribution by changing the coil’s driving currents. We will also introduce three different optimization objectives and constraints. This topic is of interest to anyone who is modeling coils or curious about optimization.

### How to Postprocess Fields over Arbitrary Geometries

##### Walter Frei April 4, 2017

Have you ever wanted to query the results of your model within an arbitrary geometric subregion? You might think that this requires adding geometries to a model and recomputing the solution. Instead, in the COMSOL Multiphysics® software, we can just add and reposition a part solely for the purpose of evaluating the results. We will demonstrate this in the context of computing mutual inductance between coils and discuss simpler techniques that can be used for a reduced set of cases.

### Designing a Sensor Package for a High-G Accelerometer via Simulation

##### Bridget Cunningham March 28, 2017

Measuring acceleration is important in high-speed dynamics, as velocity, force, and pressure are derived from it. Sensing elements inside accelerometers make it possible to obtain such measurements. As technology advances, these sensor packages must be optimized to handle higher vibrational frequency bandwidths. To accomplish this, researchers tested their novel piezoresistive sensor chip as part of a package design. Their simulation results, which agree well with experimental data, pave the way for optimizing sensor packages to achieve higher bandwidths.

### Designing and Optimizing MRI Birdcage Coils Using Simulation

##### Caty Fairclough March 24, 2017

Magnetic resonance imaging (MRI) systems must produce high-resolution images in order for doctors to accurately diagnose their patients. To achieve this level of image quality, there must be a known reliable base magnetic field distribution within the MRI machine and its components, such as birdcage coils. This is where simulation comes in. By designing MRI birdcage coils with the COMSOL Multiphysics® software, you can manipulate and optimize the magnetic field and improve the scanned data that MRI machines generate.

### Assessing a Radome Design’s Ability to Improve Antenna Directivity

##### Bridget Cunningham March 21, 2017

Exposure to the environment can negatively impact an antenna’s radiation characteristics and lead to greater losses. One way to protect these devices is with radomes, which are enclosures that can shield antennas while improving their overall performance. When designing a radome, measuring its effectiveness is key, as designs without optimized configurations have less influence. With the example of a patch antenna, we discuss using simulation to gain insight into a radome’s ability to improve antenna directivity.

### Designing CSRR-Based Sensors to Monitor Chronic Kidney Disease

##### Bridget Cunningham March 13, 2017

Noncommunicable diseases place a socioeconomic strain on low- to middle-income countries. The advent of noninvasive technology offers a solution, effectively diagnosing, preventing, and treating these diseases at a lower cost. For chronic kidney disease, one type of noncommunicable disease, such advancements are important because current methods are expensive and prone to error. As simulation research shows, sensors based on complementary split ring resonators (CSRRs) provide an inexpensive way to accurately monitor chronic kidney disease.

### Simulating the Electrothermal Transients in Superconducting Magnets

##### Bridget Cunningham March 9, 2017

When a superconducting magnet suddenly transitions to a normal state — known as a quench — its coils may overheat. Quench detection and protection systems are often included in the magnets to enable safer operation. For these systems to be effective, it’s important to understand the resulting electrothermal transient phenomena that take place within the magnet. Using numerical simulation, we can develop sophisticated systems that prevent possible disruption effects.

### How to Analyze Thermoelectric Cooler Designs with a COMSOL App

##### Nancy Bannach March 8, 2017

Thermoelectric coolers come in various types and sizes, including single-stage and multistage devices. Their application area is large, as they are used in both consumer products like cooling boxes and as temperature controllers in satellites. If you are looking to analyze the design of a thermoelectric cooler and optimize it for a specific application area, a simulation app is an efficient way to accomplish your goals. We discuss how to use the Thermoelectric Cooler demo app in this blog post.

### How to Implement the Fourier Transformation from Computed Solutions

##### Yosuke Mizuyama February 27, 2017

We previously learned how to calculate the Fourier transform of a rectangular aperture in a Fraunhofer diffraction model in the COMSOL Multiphysics® software. In that example, the aperture was given as an analytical function. The procedure is a bit different if the source data for the Fourier transformation is a computed solution. In this blog post, we will learn how to implement the Fourier transformation for computed solutions with an electromagnetic simulation of a Fresnel lens.

### Improving the Design of Monolithically Integrated Magneto-Optic Routers

##### Caty Fairclough February 17, 2017

While electro-optic (EO) routers are currently used in on-chip optical communication systems, they may require too much power for some applications. In these situations, we can look to monolithically integrated magneto-optic (MO) routers as low-power alternatives. Designing these routers can be challenging. With multiphysics simulation, we can analyze on-chip MO routers and the manufacturing techniques used to create them.