Archived

Miniaturization of Resonant Wireless Power Transfer System Components

Portable and wearable electronics require wireless charging to sustain mobile usage at convenient positions and locations. The goal is to develop a compact, highly power efficient wireless power transfer charging system operating at 6.78 MHz, which is compliant with the Rezence standard.The research scope includes development of a highly compact, high efficiency, ferrite-core receiver antenna; and a metamaterial lens to enhance WPT efficiency between the transmitter and the receiver.  In this work, we focus on WPT receiver modules for various portable and wearable consumable electronics with a power rating of ~10 W such as smart phones, radios, laptops, tablets, and military electronics. In future work, this technology could also be scalable to other power ranges, such as mW for biomedical implants to kW for automobiles.

Zero-Power Magnetic Field Sensors Using Magnetoelectric Nanowires

We seek to develop a platform that allows magnetic field sensing using a small footprint, in the absence of an external power supply. Our approach uses magnetoelectric nanofibers to create a zero-power magnetic field sensor. The challenge is to develop methods to assemble these materials into devices that leverage their unique anisotropic properties.

The figure of merit for magnetoelectric materials is the magnetoelectric coefficient, a measure of the amount of voltage generated with respect to the magnitude of the applied magnetic field. Bulk magnetoelectrics and thin films are limited by defects and substrate clamping respectively.  To overcome the limitations of thin-film based composite magnetoelectrics we have developed magnetoelectric bilayer structures on a single nanofiber, i.e., 1D magnetoelectrics. These materials are theoretically predicted to have magnetoelectric coupling coefficients that are orders of magnitude greater than their thin film counterparts. 

Magnetoelectric materials can be employed in a wide variety of applications including magnetic field sensors and tunable resonance energy harvesters.  By optimizing for material system and architecture, drastic increases in magnitude of voltage generated with decreased size can be achieved. This could allow for more sensitive magnetic field sensors appropriate for a wider array of applications and decreased size to allow for easier integration into ICs.
 

Levitated Microfactories for High-speed Adaptive Microassembly

The overall goal of UF’s effort on this DARPA Atoms to Products program (under sub-contract to SRI International) is to manufacture the micro-robots for demonstration of a massively parallel (1,000+) micro-robot factory. Each micro-robot comprises at least one magnetic base and one end effector. The magnetic base is configured with a pattern of north and south poles. A starting design is a 3 mm x 3 mm x 0.4 mm thick base that is arranged into a 9-pole checkerboard pattern. The simplest end effector is a simple mechanical rod attached to the top of the magnetic case.

The micro-robot platforms (magnetic bases and end effectors) will be mass manufactured using a combination of precision manufacturing and microfabrication techniques. Rather than assembling discrete magnets into specific pole patterns, selective magnetization techniques will be used to “imprint” the desired pole pattern into mechanically contiguous layers. These methods will eliminate the need for assembly, and also facilitate the massive batch manufacture of many magnetic bases in parallel. Concurrently, end effectors will be microfabricated using suitable microfabrication technologies. The bases and end effectors will be combined together via monolithic co-fabrication or via wafer-scale batch-assembly processes.  

Chip-Scale MEMS Receivers for Low-Power Wireless Charging

There is an increasing demand for wireless power charging of mobile electronic devices, electric vehicles, biomedical implants and IoT sensor networks. Many of the already available wireless power transmission systems are based on inductive coupling and the size ranges in the cm’s scale, linked to the large surface area requirement. A competing technology is based on an RF approach, with small size chip but impractical power levels of pW to µW, and efficiency close to unity. The alternative working principle that we propose results in a more compact solution that can be reduced to mm’s chip size while producing reasonable output power (1 mW range) at low frequency ranges (50 Hz to 1 kHz).

We have developed an electrodynamic wireless power transmission (EWPT) system that relies on the magnetic-to-mechanic-to electrical conversion from a transmitter to a remote resonator, through electrodynamic transduction. The mechanical motion of a permanent magnet is converted into electrical power, when the magnet is set in motion/rotation, by a time-varying magnetic field, next to the receiver windings.

A Flush-Mount Piezoelectric MEMS Microphone for Aeroacoustic Flight Testing Applications

In their effort to locate, understand and mitigate the impact of noise sources on an aircraft, aeroacousticiansare in need of a high performance, low cost microphone to combat the increasing noise restrictions on commercial aircraft. Existing commercial sensors, even with their relatively high cost, in some cases constrain the quality and type of measurement that may be achieved. One such constraint is that the physical size and characteristics of the sensors limit the optimal locations in which the sensors may be placed. Previous generations of MEMS aeroacoustic microphones have failed to address the need for a sensor that can be packaged and installed with a smooth front surface to be used for boundary layer measurements in a fuselage array at cruise conditions. Additionally, these microphones must meet demanding requirements, including the sensing of high sound pressure levels (>160 dB) with low distortion (<3%) and high sensitivity stability (with respect to moisture and freezing) over temperatures from -60°F to 150°F. This work addresses the limitations of existing MEMS piezoelectric microphones used in aeroacoustic applications by incorporating through-silicon vias(TSVs) into the fabrication to eliminate the use of wirebondsthat affect the flow field and create an overall flush-mount microphone package.

Modeling of the Magnetic Particle Imaging Signal Due to Magnetic Nanoparticles

Magnetic Particle Imaging (MPI) is a new tomographic imaging technique that maps the spatial distribution of iron oxide magnetic nanoparticles (MNPs) in real time and with spatial resolution that is on par or better than other biomedical imaging techniques. In this project, we will develop a theoretical foundation relating the properties of MNPs and MPI magnetic field conditions to the MPI signal strength and resolution. These efforts will yield design rules that will guide the rational design of future generations of MNP tracers for MPI. The proposed research will enable development of a novel biomedical imaging technique capable of high resolution real time imaging using nontoxic tracers suitable for a variety of biomedical applications.