Bioelectromagnetics applications

Medical devices such as magnetic resonance imaging (MRI), microwave imaging, and diathermy all rely on EM fields to operate. Designing an efficient, high-resolution MRI scanner for example requires an understanding of multiple overlaying fields at a wide range of frequencies – from the static magnetic field to the radio frequency pulse – and their complex interaction with the molecules of the body.

Electromagnetic simulation models the propagation of waves through the body, and the interaction of waves with tissues – whether this is a desired therapeutic effect or an unwanted side effect. Device engineers and physicians can use the simulation results to understand exactly how energy is absorbed by the body and validate designs and treatment protocols. This can be used, for example,  to verify the safety of implants and devices like pacemakers during a scan, or to calculate the heating pattern and safe power levels for a course of RF diathermy.

The MRI simulation solution from SIMULIA models all the different coils and their control circuits together with the patient for a full-system simulation of the scan procedure, calculating fields that can be used for a full spin simulation. This helps MRI technicians to tune the coils for an optimal image taking into account the real structure of the body.

Applications include:

• MRI
• RF and microwave imaging
• Diathermy and hyperthermy
• Implant safety
• Wearable and implantable electronics

At radio and microwave frequencies, electromagnetic waves can be significantly reflected, refracted or absorbed by the human body. This is a major cause of performance problems for portable and wearable devices such as smartphones and smartwatches, where the exact position of the hand can impact antenna performance significantly.

Safety regulations limit the radio frequency radiation exposure from many consumer and industrial devices. For many consumer devices, this is quantified by the Specific Absorption Rate (SAR) – a measure of how much power is absorbed by body tissues while in use. Other fields such as high-power transmitters and aerospace radar have similar radiation hazard (RADHAZ) KPIs, and human exposure is also a concern for low frequency fields around power lines and wireless charging points.

The performance of a device in the vicinity of the body can be analyzed in simulation and potential issues can be mitigated before committing to a physical prototype, reducing the risk of costly compliance failures later. KPIs such as SAR can be calculated automatically and any violations of specified limits are highlighted immediately.

Applications include:

• Smartphone and wireless devices
  • Body area network (BAN)
  • Hand and body signal blockage
  • 5G coverage
  • SAR
• Radar and communication RADHAZ
• Low frequency field exposure
  • Occupational safety