Research

MAJOR RESEARCH DIRECTIONS

  • Garments for Motion Capture. We are developing a new class of wearable coils that seamlessly monitor joint kinematics (flexion and rotation) in the individual’s natural environment. Our approach is not restricted to lab environments, does not suffer from integration drift and line-of-sight, and does not impede natural movement. It relies on Faraday’s Law of Induction and employs wrap-around and/or longitudinal coils that get angularly misaligned as the joint moves.

  • MagnetoCardioGraphy (MCG) Sensors. Magnetic fields that are naturally emanated by the human body propagate uninterrupted through the (non-magnetic) biological tissues, often carrying more clinical information than the corresponding electric fields. However, bio-magnetic fields are extremely weak (lower than the Earth’s magnetic field!), necessitating the use of expensive and bulky superconducting quantum interface devices (SQUIDs). Instead, we rely on passive coils operating in non-shielded environments and extensive Digital Signal Processing (DSP) to capture these fields for a variety of cardiac and neural applications.

  • Wireless Body Area Networks (WBANs) based on MagnetoInductive Waveguides (MIWs). The ever-evolving advances in electromagnetics, electronics, and materials open up new opportunities for WBANs) in healthcare, sports, defense, emergency, consumer electronics, and more. However, ultra-low-power and reliable WBAN communications have yet to be realized. To overcome these limitations, we are exploring a new classes of WBANs enabled by MIWs. With their inherent wave-guiding nature, MIWs exhibit extremely low loss; reduce power requirements of state-of-the-art WBANs by several orders; enable reliable channel modeling; are invulnerable to interference and shadowing; are highly secure; and can translate to implants with minimal alterations.

 

  • Muscle Atrophy Sensors. We are working on the first wearable sensors designed for frequent monitoring of muscle atrophy. Our approach relies on Faraday’s law of induction and exploits the dependence of magnetic flux density on cross-sectional area. We employ wrap-around transmit and receive coils that stretch to fit changing limb sizes using conductive threads (e-threads) in a novel zig zag pattern as well as liquid metal approaches. Changes in the loop size result in changes in the magnitude
    and phase of the transmission coefficient between loops.

  • High-Resolution Microwave Imaging. State-of-the-practice Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) systems are bulky and pricy, restricting imaging to the clinical setting and sparse intervals. CT also uses ionizing radiation that poses safety risks and further prohibits frequent imaging. Microwave Tomographic Imaging (MTI) is a promising alternative/complementary option, but has yet to be used in the clinical setting mainly due to its poor spatial resolution. Our group is exploring the feasibility of expanding the fundamental limits of MTI resolution via innovations artificial intelligence and ultrawideband/high-efficient into-body radiating antennas.

  • Wearable Metabolic Rate Monitors. We are exploringa smart material designed to exhibit reversible actuating behavior when exposed to skin acetone, as known to directly relate to the fat metabolism. This material is integrated with a novel electromagnetic transducer to convert shape deformations into voltage changes. All components will be ultimately embedded into a wearable skin strip that will obtain an accurate dynamical relationship between acetone and fat-metabolism. [with Prof. Perena Gouma from the Dept. of Materials Science and Prof. Manoj Srinivasan from the Dept. of Mechanical Engineering]

  • Collaborative Digital Gaming. Families who care for children with disabilities experience more challenges interacting with their children than families with normal children. This increased level of burden results in higher rates of emotional stress and hardship for families. With over 5.5 million children in the United States with physical or cognitive disabilities, our work aims to create a collaborative digital gaming platform using human-centered technology that normalizes the experience of play between the fully-abled and disabled to better serve these children, their families and communities. [with Profs. Scott Swearingen and Kyoung Swearingen from the Dept. of Design]

  • Conductive E-Textiles. We are working on a new class of e-textile antennas and sensors based on embroidered conductive threads. Our threads, referred to as e-threads, offer high surface conductivity (nearly equivalent to copper), are flexible and mechanically strong, and can be inconspicuously integrated into garments and other fabrics to realize several functionalities. As such, our technology offers very attractive RF and mechanical performance when compared to traditional rigid antennas and circuits. Example e-thread applications that we are working on include antennas for body-worn communications; reconfigurable Origami-based antennas; and magneto-actuated reconfigurable antennas on hard-magnetic soft substrates.

  • Into-Body Radiating Antennas. We are developing body-worn antennas that are composed of water-filled holes to mimic the frequency-dependent permittivity of the underlying tissue over their entire bandwidth. In doing so, unprecedented efficiencies are achieved for transmission towards the human body across ultra-wide bandwidths. We have recently verified our design framework through a novel BMA that operates from 1-12 GHz with 21.4 dB of transmission loss through 3 cm of tissue at 2.4 GHz. Compared to the most wideband and most efficient into-body radiator previously reported, this is 6.2 dB less transmission loss, with the new design also exhibiting nearly twice as much bandwidth.

  • Intracorporeal 3D Printing of Wireless Implants.

OTHER RESEARCH 

  • Stray Energy Transfer During Electrosurgery. We are exploring the underlying mechanism of injuries associated with electrosurgery. Our endoscopy studies demonstrate that unintended RF coupling occurs, increasing tissue temperature alongside the breathing tube, and potentially causing unintentional burns. Our tonsillectomy studies demonstrate that unwanted RF energy gets coupled into adjacent metal-based objects (e.g., mouth retractor), potentially causing adverse effects, such as dysgeusia.

 

  • Smart Baby BeddingWe are developing a novel class of antenna-impregnated fabrics for wireless and unobtrusive height measurement on the go. Our fabrics consist of multiple dipole antennas placed at known distances from each other. When a subject lies upon the fabric, he/she detunes the underlying antennas, inducing losses in the associated wireless transmission paths. This technology can eventually be integrated into baby cribs, bed sheets or rollable mats to provide early detection/monitoring of Turner syndrome, Crohn’s disease, short stature, Celiac disease, growth hormone deficiency, and obesity, among others.

  • Wireless and Batteryless Brain Implants. We are developing wireless and batteryless brain implants for continuous monitoring of neural activity with minimum impact to the individual’s activity. Operation lies on a microwave backscattering technique that incorporates a wearable interrogator to wirelessly turn on the implant and collect the backscattered neuropotentials. This is a game-changing capability for patients with Parkinson’s, epilepsy, etc.

  • Wideband Radiometry for Core Temperature Monitoring. Current means of measuring core temperature present a tradeoff between invasiveness and accuracy. Instead, we are exploring the feasibility of an alternative radiometry technique that leverages innovations in broadband measurements, forward modeling of layered tissues, and dry biomimetic antennas to enable non-invasive, accurate, and real-time core temperature monitoring.