Daniel Pivonka

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.

Locomotive micro-implant with active electromagnetic propulsion

An active locomotive technique requiring only an external power source and a static magnetic field is presented, and its operation is analyzed and simulated. For a modest static MRI magnetic field of 1 T, the results show that a 1-mm cube achieves roughly 3 cm/sec of lateral motion using less than 20.4 µW of power. Current-carrying wires generate the forces, resulting in highly controllable motion. Existing solutions trade off size and power: passive solutions are small but impractical, and mechanical solutions are inefficient and large. The presented solution captures the advantages of both systems, and has much better scalability.

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.

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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.

Sub-pJ/bit Reconfigurable Transceiver for mm-Sized Wireless Implants

A new propulsion method for sub-millimeter implants is presented that achieves high power to thrust conversion efficiency with a simple implementation. Previous research has shown that electromagnetic forces are a promising micro-scale propulsion mechanism; however the actual implementation is challenging due to the inherent symmetry of these forces. The presented technique translates torque into controlled motion via asymmetries in resistance forces, such as fluid drag. For a 1-mm sized object using this technique, the initial analysis predicts that speeds of 1 cm/sec can be achieved with approximately 100 µW of power, which is about 10 times more efficient than existing methods. In addition to better performance, this method is easily controllable and has favorable scalability.