Ongoing Research Projects:
Next generation of wireless power transfer network of Unmanned Aircraft System (UAS) using electromechanical beamforming
This study aims to develop the next generation of wireless power transfer (WPT) network that is scalable, safe, and efficient and can be deployed in a UAS by incorporating waveform engineering, electromechanical beamforming, integrated phased-array antenna, and transmitter (TX)/receiver (RX) co-design. This project aims to reveal the fundamental understanding of the energy sphere formation in a 3D space using UAVs as a case study. Although interests in radiative (far-field) WPT using beamforming has been growing rapidly because of its capability to energize a large number of autonomous devices, most of these works are still in the theoretical phase without any practical implementation. This project aims to implement a robust beamforming network using a bottom-up approach (from the antenna to the inter-connected network) that is highly important for addressing the challenges associated with a dynamically changing environment.
CAREER: Next-generation of Wirelessly Powered Implantable Neuromodulation and Electrophysiological Recording System for Long-term Behavior Study of Freely-Moving Animals (Feb. 2020 - Jan. 2026) (REU supplement: Sep. 2021- Aug. 2022)
The goal of the project is to develop a highly miniaturized fully implantable tetherless wireless neural signal recording and power delivery system for the next generation of neuromodulation and brain-computer interfacing. The specific objectives of the project are: 1) investigation of on-chip neural signal recording and stimulation systems that are wirelessly connected via low-power, highly duty-cycled, reconfigurable Impulse-Radio Ultra-wideband (IR-UWB) radio links, 2) integration of inductively-coupled wireless power transfer (WPT) system to power the brain implants in freely-moving animals (e.g. mice or rats) inside the cage, and 3) long-term behavior study and clinical validation of the proposed system in animal models to find cures for disabilities such as chronic neuropathic pain and post-stroke paralysis.
High Surface Area Reverse Electrowetting Mechanoelectrical Transduction (PI: Mahbub, Co-PI: Reid) (Sept. 2019 - Aug. 2023) (REU supplement: Sep. 2021- Aug. 2022
The goal of this research project is to use the hitherto unexploited surface area advantage of a liquid-based energy harvesting concept called reverse electrowetting to harvest energy from low-frequency movement and to develop a self-powered motion sensor to detect various movements such as walking and running. A miniaturized integrated circuit (IC) chip will be developed that will make the energy harvester highly suitable for other industrial and biomedical applications.
Sponsored Capstone/Senior Design Projects
RFID Tracking of Small Devices (Fall 2021 - Spring 2022, Sponsored Amount - $2,000)
High Efficiency 2GHz RF Power Amplifier (Fall 2021 - Spring 2022, Sponsored Amount - $3,750)
Radio Transceiver Subsystem Module Design for Audio Applications (Spring 2020 - Fall 2020, Sponsored Amount - $1500)
A Micro-electrode Impedance Measurement System using AD5940 Evaluation Kit (Fall 2019 - Spring 2020, Sponsored Amount - $673.84)
Long-term neural signal recording in freely-behaving animals in a laboratory experiment setting is highly important for basic brain research and studying neurodegenerative diseases such as Parkinson's disease and Alzheimer's. The biochemical environment in neural tissues can cause the degradation of the coating of the electrode materials resulting in a poor signal recording. To detect the problem it is important to continuously monitor the impedance of the electrodes at the recording site. A bioimpedance monitoring system can significantly improve the measurement quality of the neural signals by investigating the condition of electrodes and estimating the effects of cellular damage or electrode degradation. Accordingly, the determination of electrode condition and signal quality over time is important to support long term recording employing chronically implanted electrode devices. In this project, the students developed a bioimpedance measurement system that can measure the complex impedance of electrodes using the AD5940 Evaluation Kit from Analog Devices. They will characterize the impedance of the electrodes from Plexon Inc. in different solutions (e.g. saline water or other tissue-mimicking solution) and process the data in LabVIEW and display in GUI.
Integration and Assembly of a Low-cost Mask Aligner for the UNT Cleanroom (Fall 2019 - Spring 2020, Sponsored Amount - $3000)
In this project, a low-cost custom-made mask aligner will be built that would cover all the key features of a commercial mask aligner. The mask aligner will be is comprised of the special collimated high-intensity light source available in the UNT cleanroom, vacuum chuck and mask holder, high-precision translation and rotation stages, and high-resolution video camera or microscope. The total cost of the system will be under $8000, which is over ten times cheaper than the commercially available systems. It would produce a collimated illumination of 1.8-2.0 mW/cm2 over an area of a standard 4-inch wafer, at the plane of the photoresist exposure; and we aim for an alignment accuracy of < 3 μm. The capabilities of the mask aligner will be demonstrated by fabricating two-layer designs on a flexible PDMS or PEN substrates. Scanning electron microscopy will be used to confirm that the master molds contain the intended features of different heights.
Transcutaneous Wireless Power Transfer and Bio-telemetry System with closed-loop power regulation
Project Description: Although inductively-coupled wireless power transfer system has been significantly developed in the past few decades for implantable sensors, the efficient and continuous transfer of power still remains as a challenge as the distance and alignment between the transponder and the receiver vary over time. This project investigates the variations in the coupling between the coil due to the environmental factors such as displacements, misalignment, frequency detuning and loading effects in order to model the variations. This model will help in predicting the power loss due to these variations as well as develop the closed-loop power regulation circuitry for ensuring high power-transfer efficiency.
Low-power Wireless Neural Signal Acquisition System
Project Description: Although there have been several approaches for the recording the neural signals, efficient acquisition of µV-level signal while removing the large offset and low-frequency noise is still a critical issue in neuroscience research. This project aims at developing a low-power multi-channel wireless neural signal acquisition system that can mitigate the large DC offset and noise issues. As a prototype, neural amplifiers using 0.5 um and 130 nm standard CMOS processes are fabricated that have a high gain (> 54 dB), a high common-mode rejection ratio, CMRR (>90 dB) and a low input-referred noise (<4 uVRMS) with a power consumption of less than 4 uW per channel. For the next prototype, a 16-channel fully implantable neural recoding system will be fabricated. 16 LNA as well as an 8 bit SAR ADC (sampling frequency 4.092 kHz) and 3.1 - 5 GHz Impulse-radio Ultrawideband (IR-UWB) transmitter are integrated into the neural recording system implemented on the same CMOS die that is only 1.5 mm by 1.5 mm in dimension and consumes only 500 uWs of power.
A Prototype Miniaturized Wirelessly Powered Neural Stimulation and Recording System for Brain Optogenetics
Project Description: The goal of this study is to develop a self-reconfigurable optical stimulation and recording system that would allow the neuroscientists to record the effects and the changes in the behavior patterns of the animals for various duration and intensity of optical stimulations in the study of Optogenetics.
PI: Ifana Mahbub, UNT ORED Research Seed grant, 10/15/17-08/31/18
Previous Research Projects:
Investigating the risks of Electromagnetic Interference (EMI) and Electro-static Discharge (ESD) on the microelectronics imposed by the spray painting guns
Project Description: Electrostatic spray paint guns have been extensively used especially in the auto-industry to coat the vehicle chassis with the desired colors. As the technology is advancing day-by-day, more and more features are being added to the vehicle, which is requiring multi-purpose sensors and electronics to be placed in the vehicle. This project aims to look at the possibilities of the generation of EMI generated by the electrostatic spray paint guns and the effects of the ESD and EMI on the microelectronics that are typically placed on the chassis of the vehicle. Concurrently, this project also aims to investigate the possible solutions to mitigate the EMI generated during the ESD based painting process.
Wireless Respiration Monitoring Sensor for Sleep Apnea
Wireless devices for monitoring respiration activities can play a major role in advancing the modern home-based healthcare applications. Chronic respiratory diseases such as apnea are even more critical for premature neonatal infants. This project included the design and implementation of a low-power wireless respiration monitoring sensor which can reduce the cost and inconvenience of the conventional respiration monitoring systems significantly. At the front-end of the system, a ferroelectric polymer (PVDF) based pyroelectric transducer is utilized to monitor the temperature difference between the room air and the nasal air-flow. The charge generated by the transducer due to this temperature change is then converted to a proportional voltage signal using a low-power low-noise folded-cascode operational transconductance (OTA) based charge amplifier. A pseudo-resistor based diode-connected MOSFET in the feedback configuration is implemented to achieve sub-Hz corner frequency that is required for low-frequency respiration signal monitoring. An apnea detection algorithm has been also implemented as a part of this project.