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Cardiac Device Gets Wireless Technology


Wireless power could pave the way for next-gen implanted medical devices …

Stanford engineers have developed a cardiac implant that can be powered wirelessly, and is small enough to propel itself through the blood stream.

The technology could lead to wireless power for all medical implants, and without the need for a battery, devices such as pacemakers can be drastically reduced in size. In addition, the surgery required to replace batteries could be eliminated altogether.

wireless technology to make pacemakers smaller

Wireless Cardiac Implant Could Make Pacemakers Much Smaller

Image Credit: Lucien Monfils, 2008.

Developed by Ada Poon, assistant professor of electrical engineering at Stanford, and her colleagues, the proof-of-concept cardiac device measures just 0.8 millimeters and contains a coil that receives and transmits radio waves.

The tiny size of the device was not the teams biggest breakthrough, that came after they figured out that the implant could still receive power even if it was implanted on the heart, under 5 centimeters of human tissue.

Radio waves are sufficient to provide power for small devices, however smaller coils need to receive higher frequency radio waves to generate this power. Previous mathematical models showed that high frequency radio waves do not penetrate human tissue very well, but Poon and her team re-crunched the numbers and found this not to be true.

After careful revision, they found that power can transfer through human tissue at up to 1.7 billion cycles per second much higher than previously thought. This allowed them to increase the power transfer 10 times more than on previous devices, which means they could also shrink the antenna by a factor of 10.

The team claims that a millimeter-radius coil can generate more than 50 microwatts of power – a pacemaker require around 8 microwatts.

Although the technology still has a long way to get before it will be implanted into medical devices, Poon is currently applying for patent on the antenna structure, and will continue to research and refine the device.

The team’s research was published in the Journal Applied Physics Letters.

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