A5044898858- Neuroscience and Neural Engineering
- Antenna Design and Analysis
- Energy Harvesting in Wireless Networks
- Photoreceptor and optogenetics research
- Wireless Body Area Networks
- Advanced Memory and Neural Computing
- Wireless Power Transfer Systems
- EEG and Brain-Computer Interfaces
- Muscle activation and electromyography studies
- Electromagnetic Simulation and Numerical Methods
- Electromagnetic Compatibility and Measurements
- Microwave Engineering and Waveguides
- Electromagnetic Fields and Biological Effects
- Transcranial Magnetic Stimulation Studies
- IPv6, Mobility, Handover, Networks, Security
- Antenna Design and Optimization
- Neural dynamics and brain function
- Molecular Communication and Nanonetworks
- Advanced MIMO Systems Optimization
- Retinal Development and Disorders
- Advanced Antenna and Metasurface Technologies
- Electromagnetic Scattering and Analysis
- CCD and CMOS Imaging Sensors
- Planarian Biology and Electrostimulation
- Microwave Imaging and Scattering Analysis
University of Southern California
2018-2025
Southern California Eye Institute
2023-2025
Arizona State University
2019-2024
University of Pennsylvania
2019-2024
BAE Systems (United States)
2023-2024
Gorgias Press (United States)
2021-2024
Colorado State University
2023-2024
Southern California University for Professional Studies
2024
Chiba University
2021-2024
Advisory Board Company (United States)
2023-2024
Abstract This paper describes the fabrication and characterization of fluidic dipole antennas that are reconfigurable, reversibly deformable, mechanically tunable. The consist a fluid metal alloy injected into microfluidic channels comprising silicone elastomer. By employing soft lithographic, rapid prototyping methods, easier to fabricate than conventional copper antennas. radiates with ≈90% efficiency over broad frequency range (1910–1990 MHz), which is equivalent expected for similar...
The authors have used the finite-difference time-domain method and a new millimeter-resolution anatomically based model of human to study electromagnetic energy coupled head due mobile telephones at 835 1900 MHz. Assuming reduced dimensions characteristic today's telephones, obtained SAR distributions for two different lengths monopole antennas /spl lambda//4 3/spl lambda//8 adult male reduced-scale models 10- 5-year-old children find that peak one-voxel 1-g SARs are larger smaller children,...
This paper describes a flexible microstrip patch antenna that incorporates novel multi-layer construction consisting of liquid metal (eutectic gallium indium) encased in an elastomer. The combined properties the fluid and elastomeric substrate result durable is well suited for conformal applications. Injecting into microfluidic channels provides simple way to define shape liquid, which stabilized mechanically by thin oxide skin forms spontaneously on its surface. approach has proven...
Failure of central nervous system (CNS) axons to regenerate after injury results in permanent disability. Several molecular neuro-protective and neuro-regenerative strategies have been proposed as potential treatments but do not provide the directional cues needed direct target-specific axon regeneration. Here, we demonstrate that applying an external guidance cue form electric field stimulation adult rats optic nerve crush was effective at directing long-distance, retinal ganglion cell...
Two-coil based inductive coupling is a commonly used technique for wireless power and data transfer biomedical implants. Because the source load resistances are finite, two-coil systems generally achieve relatively low efficiency. A novel multi-coil (using more than two coils) considered to help overcoming this limitation. The proposed system formulated using both network theory two-port model. Using three or four coils link allows be decoupled from Q-factor of coils, resulting in higher Q...
This letter describes the fabrication and characterization of a shape shifting antenna that changes electrical length therefore, frequency, in controlled rapid response to pressure. The is composed liquid metal alloy (eutectic gallium indium) injected into microfluidic channels feature rows posts separate adjacent segments metal. initial stabilized mechanically by thin oxide skin forms on Rupturing merges distinct metal, which rapidly length, therefore antenna. A high speed camera elucidates...
This communication presents antennas that incorporate self-folding polymer substrates transform planar, two-dimensional structures into three-dimensional when exposed to a light source. Pre-strained polystyrene sheets supporting patterned copper foil form the light-activated structures. Black ink is inkjet printed on substrate selectively absorbs and controls shape of transformation. approach represents simple method reconfigure an antenna hands-free assemble 3D from many conventional...
Wireless power transfer using resonant inductive coupling has been employed in a number of applications, including wireless charging electronic devices and powering implanted biomedical devices. In these is transferred over short distances, which are much smaller (~ λ/100) than the wavelength operation. such systems, efficiency link inversely related to range The principally function Q's individual coils between them. this paper, we demonstrate improvements efficiencies negative permeability...
This paper describes the realization of a soft, flexible, coil fabricated by means liquid metal alloy encased in biocompatible elastomeric substrate for operation telemetry system, primarily application to biomedical implantable devices. Fluidic conductors are fact well suited applications that require significant flexibility as conformable and stretchable devices, such coils wireless telemetry. A with high conductivity, therefore low losses unloaded Q factor, is required realize an...
An extremely compact and low-frequency metamaterial design is presented in the following work. A ferrite loaded solenoid with a size on order of 1/10000 wavelength operation used as unit cell proposed metamaterial. This allows for construction 77 unit-cell sample dimensions 6 cm × 2 operating at working frequency 5.57 MHz. Measurements show that using this wireless power transfer (WPT) system results an efficiency enhancement 10% distance 4.5 cm, which twice original same distance....
Rapid advances in antennas, propagation, electromagnetics, and materials are opening new unexplored opportunities body area sensing stimulation. Next-generation wearables implants seamlessly providing round-the-clock monitoring. In turn, numerous applications brought forward with the potential to ultimately transform healthcare, sports, consumer electronics, beyond. This review paper provides a comprehensive overview, discusses challenges opportunities, indicates future directions for: (a)...
In this work, an extremely compact planar meander line dipole is designed and implemented for use as intraocular element in a retinal prosthesis. This antenna exhibits high degree of current vector alignment impedance matched by inducing phase reversal along its length. induced minor offset feed location which yields highly directive broadside radiation pattern on particular geometry. concept applied designing implementing 6/spl times/6 mm wire at 1.4 GHz the data telemetry link Coupling...
Wireless networks consisting of compact antennas find applications in diverse areas such as communication systems, direction arrival estimation, sensor networks, and imaging. The effectiveness many these systems depend on maximizing the reception RF power extracting maximum information from incident electromagnetic (EM) wave. Traditionally, this has been achieved through multiple-input multiple-output (MIMO) employing a spatial array that enhance channel capacity. In paper, we report similar...
In this paper, we investigate a novel approach of establishing data telemetry link for dual-unit retinal prosthesis at microwave frequencies (1.45 and 2.45 GHz) using pair microstrip patch antennas. Appropriately sized extraocular (25/spl times/25 mm) intraocular (6/spl times/6 antennas are designed to operate both the finite-difference time-domain method, coupling between them is examined computationally in presence 0.25-mm resolution human-head model. Good agreement numerical experimental...
An explicit finite-difference time-domain formulation of the bio-heat equation is employed with a three-dimensional head eye model to evaluate temperature increase in and surrounding tissues due operation implanted stimulator IC chip retinal prosthesis designed restore partial vision blind. As first step, validation thermal method used carried out by comparison vivo measurements intraocular heating performed eyes dogs. Induced then estimated for several different operational conditions chip....
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Recently it was shown that co-located vector antennas can provide the same capacity increase as spatial array in multiple-input multiple-output (MIMO) systems. This paper describes design of a antenna consisting loop and two orthogonal bowtie for ultrawideband (UWB) MIMO system operates frequency range 3.6–8.5 GHz. Channel calculations performed with operating rich scattering environment show...
This letter describes a fluidic microstrip bandstop filter with transmission properties that change in discrete states. The consists of liquid metal alloy - eutectic gallium indium (EGaIn) as the conductive component microfluidic channels. fluidity EGaIn allows open stub resonator to its length by flowing response an applied pressure. A series posts channel defines filled and dictates pressure needed for flow thereby extend length. frequency changes stub. approach is simple method creating...
Inductive coupling-based wireless power transfer (WPT) is commonly used for near-field and data to implanted electronics. Some coils undergo relative motion during device operation causing variation in magnetic coupling from their normal position. To ensure stable efficiency frequency bandwidth, these WPT systems should have high tolerance with variation. In this letter, a multicoil-based system utilized achieve bandwidth. It demonstrated that multicoil can reduce by half (PTE) one third...
Wireless power transfer is a practical and widely used method to various implantable devices. Commonly, the implanted receiver (RX) must be small, often on order of millimeter, which poses significant design challenges. In this paper, technique improve performance systems with size (inductance)-limited RX coil explored. Conventionally, only mutual coupling between coils optimize performance, constrains layout/geometry choice coils. proposed system, coupling, capacitance, relative polarity...
We present a compact, magnetically dispersive engineered surface for resonant inductive wireless power transfer (WPT) that significantly enhances the performance of an link, increasing efficiency and/or working distance. The proposed metasurface measures 6 cm × 0.1 cm, achieving greatly reduced thickness over 3-D metamaterial, especially relative to long wavelength at chosen operating frequency 5.77 MHz, which is in range typical biomedical implants. Such feature obtained by virtue extremely...
Abstract As the clinical applicability of peripheral nerve stimulation (PNS) expands, need for PNS‐specific safety criteria becomes pressing. This study addresses this need, utilizing a novel machine learning and computational bio‐electromagnetics modeling platform to establish criterion that captures effects fields currents induced on axons. Our approach is comprised three steps: experimentation, model creation, predictive simulation. We collected high‐resolution images control stimulated...