Wireless Sensors/Systems

We are developing ultra-compact antennas, where the antenna size is much smaller than the electromagnetic wavelength.

Pervasive wireless connectivity is a must for today’s interconnected world.  Many MHz-GHz communication systems require antennas with physical sizes that can be much larger than the entire size of the system.  It is difficult to achieve good antenna performance if the size of the antenna is less than 1/10^ththe electromagnetic wavelength (e.g. minimum of 3 cm at 1 GHz)

This collaborative research project will create a practical control scheme for large swarms of microrobots. These robots are typically no more than a few millimeters in length, and rely on an external power source and control signal. Currently, it is possible to steer the swarm as a whole to a single destination (or perhaps, to a desired average location). However, realizing the full potential benefits of microrobot swarms will require the ability to simultaneously send independent commands, either to individual robots or to small subgroups.

We are developing time-resolved dynamic pressure sensing technology for high-temperature (> 1000 °C) applications in the aerospace, energy, and automotive sectors and for chemical environment sensors for biotechnology companies.

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.

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.
 

Research Objectives

To develop a wireless shear-stress sensor array to provide three-dimensional, time-resolved, fluctuating skin friction data to aid turbulence model development.

Approach

Each sensor is effectively an LC tank made up of a variable-capacitance floating element and an integrated inductor. The sensing antenna is inductively coupled to the tank and can detect a change in the resonant frequency caused by a displacement of the floating element. An array is realized by designing each sensor to have it’s own unique resonant frequency. Then a single broad spectrum antenna can monitor the entire array.

Broader Impact

The realization of such an array will enable fundamental scientific studies of complex turbulent flows. It could also be implemented into a feedback control system for future air vehicles employing active flow control.