Friday, March 3, 2017

E3 Simulation and Analysis: A conversation with David Johns.

In anticipation of our upcoming workshop on Electromagnetic Environmental Effects (E3), we spoke with David Johns, Vice President of Engineering at CST of America. David will be leading the workshop and we spoke to him about some of the topics attendees can expect to learn more about. The workshop will take place on May 11th 2017 in National Harbor, MD just outside of Washington DC. If you are interested in attending, head over to our website to register. 

CST: Thanks for taking some time to speak with us about the upcoming E3 workshop. To begin, could you give us an overview of the workshop?

David Johns: Certainly. This workshop is intended to provide a forum for Engineers and Scientists working in the area of Electromagnetic Environmental Effects (E3) to meet and exchange ideas about the use of electromagnetic and multi-physics simulation. Simulation is playing a growing role in E3 design and analysis for several reasons. Modern materials such as composites may provide less protection from E3 threats and simulation can be used to study the potential vulnerabilities early in the design phase. Physical testing of vehicles and aircraft for E3 requirements and verification can be both time-consuming and expensive. There is a trend towards balancing physical testing with simulation. Simulation may also provide information that is difficult to obtain by testing. For example, many tests have to be performed on the ground. Simulation can be used to simulate free space environments, enabling normalization of ground-based test data.

Radiation Hazard (RADHAZ) is one of the prominent topics of this workshop. What are some of the threats that it poses, and how can it be mitigated?

Radiation Hazards are an important part of the E3 consideration. It is important to maintain the safety of personnel in an electromagnetically dense environment, and it is important to protect against high-intensity fields from accidentally triggering fuel tank ignition or ordnances. Measures to mitigate RADHAZ include controlling current paths taken through the structure, applying shielding in critical areas and positioning high-intensity transmitters to avoid field levels in personnel areas that exceed permitted thresholds, while also avoid co-site interference (EMI) between different electronics systems.

E3 analysis is usually carried out on large platforms such as vehicles, aircraft, and buildings, but very small features such as seams, vents, and cables have a significant effect on shielding performance. How can these multi-scale models be simulated effectively?
A narrow gap or seam in a conducting structure can be a serious weakness in the design, especially if it runs over a long distance. If the wavelength of the EM field is comparable to the gap/seam length, resonances will be excited. The dimensions of seams can be several orders of magnitude smaller than the overall structure dimensions. This makes it a real challenge to capture this important detail. This multi-scale problem can be handled efficiently by incorporating equivalent electrical models of the behavior of the detail into the electromagnetic field solver.

You mentioned co-site interference as another subject of particular interest in regards to E3. What tools does CST offer for co-site interference analysis?

The complete electromagnetic solver technology in CST STUDIO SUITE® is ideal for simulating the unintentional coupling between different electronics systems (antenna to antenna, PCB to antenna, etc.). In the latest version 2017 release, a new tool has been introduced called the Interference Task. This tool enables the spectral profile of transmitters/radiators and sensitivity of receivers to be defined and combined with the coupling information to analyze the possibility of co-site interference (EMI). The interference task is integrated fully into CST STUDIO SUITE enabling parametric studies such as the relative positioning of electrical components and impact on EMI.

David Johns
Vice President of Engineering- CST of America

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