WSAudiology develops leading-edge hearing aids with SIMULIA simulation

WSAudiology (WSA) is one of the world's largest manufacturers of hearing aids. Their highly advanced audiology technology is compact, reliable, and affordable. WSA uses SIMULIA's CST Studio Suite to optimize designs to the limits of physics. Faster and more precise simulations help WSA speed up product development cycles and allow them to maximize innovation.

We interviewed several experts at WSAudiology to learn more.

 

How can something so small be so complex?

Video Transcript 

Hearing aids are very complex devices. There is a lot of signal processing happening inside.There are antennas and coils picking up electromagnetic fields and lots of interferers packed together in the very small volume of a hearing aid. 

Therefore, the antenna comes very close to the interfering signals, which is creating big issues for us. 

 

Stephan Lensing, Simulation Key Expert, WSA Erlangen

 

What is a T-coil and why is it important?

We are looking into three wireless systems in our hearing aids. One of those is the T-Coil, which is picking up an electromagnetic field in the audio range at very low frequencies of only a few Hertz. A T-coil is essentially a wire wound around a rod, designed to pick up magnetic fields from induction loop systems commonly found in public places such as churches, temples, railway stations, and theaters. One of the key challenges is that hearing aids also contain other wireless systems, like the near-field magnetic induction antenna and the RF antenna. These systems need to coexist, but the T-coil is highly sensitive to their magnetic fields.

To address this, we use simulation to understand the interference between the different systems. By modeling the T-coil and the entire hearing aid, we can study the coupling between these systems. Simulation enables us to analyze the interactions and develop effective solutions.

 

Stephan Lensing, Simulation Key Expert, WSA Erlangen

Sithara Syed Nasser, Simulation Key Expert, WSA Singapore

 

How do hearing aids communicate with one another?

The second wireless system is our near field magnetic induction (NFMI) link, which establishes communication between the left and the right hearing aid. They can exchange commands and even digitized speech to enable advanced signal processing for better hearing.  

The MI link uses Near Field Magnetic Induction (NFMI) and it is based on the principle of resonant inductive coupling between two matched coils which form an LC circuit working on the same resonant frequency. We transmit the magnetic signal from one ear to the other ear, so it is basically the short-range wireless communication. The MI link consumes very low power and the field strength is really low, and there is a lot of interference with the other electronic systems in the hearing aid. 

We test in a virtual environment so that we can understand the problem beforehand, and we could locate the aggressors in the simulations and we could visualise it before it comes into the picture and becomes a problem during physical testing in the lab.

 

Stephan Lensing, Simulation Key Expert, WSA Erlangen

Mrinalinee Pandey, Simulation Key Expert, WSA Lynge

 

What challenges does simulation address in Bluetooth communication?

The third wireless system we have is the RF system which is used to connect the hearing aid to a device in the outside world.

We want you to be able to connect your hearing aid directly to your smartphone, to your TV or to other devices in the world outside. The main challenge is that the body is in between and waves propagate quite differently along the body than they do in free space. 

We set up a simulation where we placed the hearing aids on the ear and included the full body. We were able to create a very fine mesh, create the field source and then bring that to a body phantom in CST Studio Suite, allowing us to understand how the waves propagate along the body. If we didn't have CST Studio Suite, we wouldn't have been able to optimize the hearing aid in that way. 

 

Stephan Lensing, Simulation Key Expert, WSA Erlangen

Martin Schmidt, Simulation Key Expert, WSA Erlangen

 

What do you love about SIMULIA Simulation?  

With CST Microwave Studio, we can now create complete models of our hearing aids for all relevant frequency ranges. This gives us the opportunity to bring components closer together, which, in the end, will allow us to have great connectivity at an even smaller volume.

Stephan Lensing, Simulation Key Expert, WSA Erlangen

 

I love CST because it gives me the option to understand the waves propagating along the body to optimize the hearing aids and to get a deeper insight into what happens in the electromagnetics.

Martin Schmidt, Simulation Key Expert, WSA Erlangen

 

I love SIMULIA because I can experiment with my ideas 

Sithara Syed Nasser, Simulation Key Expert, WSA Singapore

 

I love SIMULIA because it gives me a better understanding of the problems and helps me to find a solution. 

Mrinalinee Pandey, Simulation Key Expert, WSA Lynge