Anatoly Yakovlev

Implantable biomedical devices: Wireless powering and communication

In recent years, there has been major progress on implantable biomedical systems that support most of the functionalities of wireless implantable devices. Nevertheless, these devices remain mostly restricted to research, in part due to limited miniaturization, power supply constraints, and lack of a reliable interface between implants and external devices. This article provides a tutorial on the design of implantable biomedical devices that addresses these limitations. Specifically, it presents analysis and techniques for wireless power transfer and efficient data transfer from both theoretical and practical standpoints. Their potential implementations are also discussed.

A mm-Sized Wirelessly Powered and Remotely Controlled Locomotive Implant

A wirelessly powered and controlled implantable device capable of locomotion in a fluid medium is presented. Two scalable low-power propulsion methods are described that achieve roughly an order of magnitude better performance than existing methods in terms of thrust conversion efficiency. The wireless prototype occupies 0.6 mm × 1 mm in 65 nm CMOS with an external 2 mm × 2 mm receive antenna. The IC consists of a matching network, a rectifier, a bandgap reference, a regulator, a demodulator, a digital controller, and high-current drivers that interface directly with the propulsion system. It receives 500 μW from a 2 W 1.86 GHz power signal at a distance of 5 cm. Asynchronous pulse-width modulation on the carrier allows for data rates from 2.5-25 Mbps with energy efficiency of 0.5 pJ/b at 10 Mbps. The received data configures the propulsion system drivers, which are capable of driving up to 2 mA at 0.2 V and can achieve speed of 0.53 cm/sec in a 0.06 T magnetic field.

A mm-sized wirelessly powered and remotely controlled locomotive implantable device

Fully autonomous implantable systems with locomotion can revolutionize medical technology, and include applications ranging from diagnostics to minimally invasive surgery. However, the extreme power requirements of fluid locomotion impose significant design challenges. Using highly efficient and scalable electromagnetic propulsion systems, these locomotive devices become possible. Recent work shows that mm-sized antennas in tissue achieve optimal power transfer efficiency in the low-GHz range. Combining this power transfer method with the highly efficient propulsion, a fully wireless locomotive implant capable of moving at 0.53cm/s has been realized in 65nm CMOS with a 2mm × 2mm receive antenna and a 0.6×1mm2 die size with a 2W 1.86GHz carrier. The design consists of an RF frontend, bandgap reference, regulator, demodulator, digital control, and configurable high-current drivers for the propulsion system.

An 11

A wirelessly powered 11 μW transceiver for implantable sensors has been designed and demonstrated through 35 mm of porcine heart tissue. The prototype occupies 1 mm × 1 mm in 65nm CMOS with an external receive antenna. The IC consists of a rectifier, regulator, demodulator, modulator, controller, and sensor interface. The forward link transfers power and data on a 1.32 GHz carrier using low-depth ASK modulation that minimizes impact on power delivery and achieves from 4 to 20 Mbps with 0.3 pJ/bit at 4 Mbps. The backscattering link modulates the antenna impedance with a configurable load for operation in diverse biological environments and achieves 2 Mbps at 0.7 pJ/bit. The device supports TDMA, allowing for simultaneous operation of multiple sensors.A wirelessly powered 11 μW transceiver for implantable devices has been designed and demonstrated through 35 mm of porcine heart tissue. The prototype was implemented in 65 nm CMOS occupying 1 mm × 1 mm with a 2 mm × 2 mm off-chip antenna. The IC consists of a rectifier, regulator, demodulator, modulator, controller, and sensor interface. The forward link transfers power and data on a 1.32 GHz carrier using low-depth ASK modulation that minimizes impact on power delivery and achieves from 4 to 20 Mbps with 0.3 pJ/bit at 4 Mbps. The backscattering link modulates the antenna impedance with a configurable load for operation in diverse biological environments and achieves up to 2 Mbps at 0.7 pJ/bit. The device supports TDMA, allowing for operation of multiple devices from a single external transceiver.

\mu{\rm W}

A wirelessly powered 11 μW transceiver for implantable sensors has been designed and demonstrated through 35 mm of porcine heart tissue. The prototype occupies 1 mm × 1 mm in 65nm CMOS with an external receive antenna. The IC consists of a rectifier, regulator, demodulator, modulator, controller, and sensor interface. The forward link transfers power and data on a 1.32 GHz carrier using low-depth ASK modulation that minimizes impact on power delivery and achieves from 4 to 20 Mbps with 0.3 pJ/bit at 4 Mbps. The backscattering link modulates the antenna impedance with a configurable load for operation in diverse biological environments and achieves 2 Mbps at 0.7 pJ/bit. The device supports TDMA, allowing for simultaneous operation of multiple sensors.