A5053383386- Microwave Engineering and Waveguides
- Antenna Design and Analysis
- Microwave Imaging and Scattering Analysis
- Ultra-Wideband Communications Technology
- Non-Invasive Vital Sign Monitoring
- Radio Frequency Integrated Circuit Design
- Advanced Antenna and Metasurface Technologies
- Indoor and Outdoor Localization Technologies
- Antenna Design and Optimization
- Millimeter-Wave Propagation and Modeling
- Advanced SAR Imaging Techniques
- Physics of Superconductivity and Magnetism
- Radar Systems and Signal Processing
- Energy Harvesting in Wireless Networks
- Gyrotron and Vacuum Electronics Research
- Geophysical Methods and Applications
- Wireless Body Area Networks
- Advanced Power Amplifier Design
- Hemodynamic Monitoring and Therapy
- ECG Monitoring and Analysis
- Particle accelerators and beam dynamics
- Sparse and Compressive Sensing Techniques
- Electromagnetic Compatibility and Noise Suppression
- Acoustic Wave Resonator Technologies
- Microwave and Dielectric Measurement Techniques
University of Tennessee at Knoxville
2016-2025
Knoxville College
2007-2025
Cairo University
2023-2024
Al-Azhar University
2018-2023
Applied Radar (United States)
2023
Al-Ryada University for Science and Technology
2022
German University in Cairo
2014
University of Hawaiʻi at Mānoa
2007
University of Hawaii System
2007
Honolulu University
2007
Looking to increase the functionality of current wireless platforms and improve their quality service, we have explored merits using frequency-reconfigurable antennas as an alternative for multiband antennas. Our study included analysis various reconfigurable structures such patches, wires, combinations. Switches, radio-frequency microelectromechanical systems (RFMEMS) p-i-n diodes, were also studied directly incorporated onto antenna successfully form
Two different types of Vivaldi antenna arrays have been designed for UWB see through wall applications.The first is a 16 × 1 antipodal covering 8-12 GHz, and the second an 8×1 tapered slot 2-4 GHz frequency range.The array elements are optimized to compact size almost constant gain with frequency.Wilkinson power dividers were fabricated compose feed network arrays.Measured results manufactured in excellent agreement simulated ones, more than 13 dBi 12 respectively within their respective...
There are many challenges in building an ultra-wideband (UWB) indoor local positioning system for high-accuracy applications. These include reduced accuracy due to multipath interference, sampling rate limitations, tag synchronization, and antenna phase-center variation. Each of these factors must be addressed achieve millimeter or sub-millimeter accuracy. The developed architecture is presented where a 300-ps Gaussian pulse modulates 8-GHz carrier signal transmitted through omni-directional...
In this paper, we propose a novel architecture for ultra-wideband (UWB) positioning systems, which combines the architectures of carrier-based UWB systems and traditional energy detection-based systems. By implementing architecture, have successfully developed standalone noncoherent system both static dynamic targets in an indoor environment with approximately 2 5 mm 3-D accuracy, respectively. The results are considered great milestone developing such technology. 1-D experiments been...
In this paper, we discuss using field-programmable gate arrays (FPGAs) to process either time- or frequency-domain signals in human sensing radar applications. One example will be given for a continuous-wave (CW) Doppler and another an ultrawideband (UWB) pulse–Doppler (PD) radar. The the CW utilizes novel superheterodyne receiver suppress low-frequency noise includes digital downconverter module implemented FPGA. Meanwhile, UWB PD employs carrier-based transceiver equivalent time sampling...
A compact Vivaldi antenna array printed on thick substrate and fed by a Substrate Integrated Waveguides (SIW) structure has been developed. The utilizes SIW binary divider to significantly minimize the feed insertion losses. low-loss common novel Grounded Coplanar Waveguide (GCPW) provide wideband transition sustain good input match while preventing higher order modes excitation. was designed, fabricated, thoroughly investigated. Detailed simulations of its feed, in addition relevant...
Ultra-wideband (UWB) pulse Doppler radars can be used for noncontact vital signs monitoring of more than one subject. However, their detected signals typically have low signal-to-noise ratio (SNR) causing significant heart rate (HR) detection errors, as the spurious harmonics respiration and mixed products heartbeat (that relatively higher signals) corrupt conventional fast Fourier transform spectrograms. In this paper, we extend complex signal demodulation (CSD) arctangent (AD) techniques...
Dielectric rod antenna (DRA) elements have numerous advantages over conventional waveguide and horn elements. They low insertion loss, broadband input match, high mutual decoupling efficiency, low-cost manufacturing. Additionally, the radiation pattern of dielectric is almost frequency-independent. However, its feeding generally a challenge. This paper demonstrates novel ultrawideband (UWB) eight-element DRA fed by wideband substrate integrated (SIW) structure. The eight-way feed net work...
In this letter, a phase-based algorithm based on logarithmic method, applicable to UWB radars and suitable real-time monitoring, is proposed detect the phase variations of reflected pulses caused by tiny cardiac motions. Compared with conventional FFT vital signs detection demonstrates advantage in respiration harmonics suppression avoidance intermodulation between heartbeat signals. Furthermore, it experimentally shown that Doppler radar capable multiple heartbeats subject...
Remote non-contact monitoring of human vital signs has recently received lots attention due to the advancement and availability millimeter wave (mmWave) radars. These sensors are significantly reduced in size, but still face serious electromagnetic (EM) propagation loss signal obstructions resulting lower signal-to-noise ratios (SNR). As mmWave signals also have higher sensitivity body motions, these effects typically degrade accuracy heart rate (HR) detection. To overcome this challenge,...
Abstract This paper presents an approach for designing metasurface antennas using the characteristic mode analysis method 5G mm-wave multiple input–multiple output (MIMO) systems. The proposed antenna consists of a 3 × array modified patches with additional slits and stubs, which are fed by coupling slot. configuration reshapes surface currents improves radiation performance across broad frequency range. design offers significant advantages such as reduced size, minimized influence...
It is known that a radial power combiner very effective in combining large number of amplifiers, where high efficiency (greater than 90%) over relatively wide band can be achieved. However, its current use limited due to design complexity. In this paper, we develop step-by-step procedure, including both the initial approximate formulas and suitable models for final accurate optimization purposes. Based on three-dimensional electromagnetic modeling, predicted results were excellent agreement...
This paper presents the development of a low-cost real-time ultrawideband (UWB) see-through-wall (STW) imaging radar system. The designs microwave front end, UWB data acquisition, and system integration are discussed in detail. As for most challenging task, we introduce custom module based on commercial field-programmable gate array (FPGA) boards low-speed analog-to-digital converters. introduced does not require implementation high-speed wideband mixed-signal circuitry but only depends FPGA...
We have performed intra- and extra-cavity microwave frequency (1–100 GHz) measurements on high quality Y1Ba2Cu3O7−x superconducting thin films (100) LaAlO3 substrates. The ∼0.3 μm fabricated by the pulsed laser deposition technique exhibit transition temperatures >90 K, as determined resistivity ac susceptibility measurements, critical current densities of 5×106 A/cm2 at 77 K. Moreover, ion beam channeling minimum yields ∼3% were measured, indicating extremely crystalline grown...
Technology that can be used to unobtrusively detect and monitor the presence of human subjects from a distance through barriers powerful tool for law enforcement, military, health monitoring applications. To this end, ultra-wide band radar has shown promise real-time subject imaging, compact Doppler solutions have demonstrated potential providing non-invasive detection cardiopulmonary activity multiple subjects. These technologies work walls other obstructions, even leverage ambient radio...
A Ku-band cavity-backed microstrip patch 2 x antenna array has been implemented using the substrate-integrated waveguide (SIW) technology-a low-cost multilayer printed circuit board (PCB) process. Cavities are emulated vias, and patches fed lines that centrally by a shielded coaxial probe feed line. Simple design guidelines for cavity, patch, substrate selection presented. The was fabricated, its measured results agreed very well with theoretical predictions indicated relatively high...
A previously developed simulation platform for localization purposes has been extended and customized to accurately analyze simulate ultra wideband (UWB) through-wall imaging (TWI) synthetic aperture radar (SAR) systems as well. The newly added features/modules include electromagnetic simulator account wall presence target scattering, a backprojection algorithm, different transceiver architectures antenna array configurations. is capable of time gating suppress early reflections simulates...
In this paper, we compare the performance of radar and optical (camera based) techniques in detecting vital signs such as respiratory rate (RR), heart (HR), blood oxygen saturation (SpO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ). Specifically, investigate application ultrawideband stepped-frequency continuous-wave imaging photoplethysmography (iPPG) to measure signs. The can be enhanced by using phase information backscattered...
Medical monitoring has improved over the last four decades to include increasingly less invasive techniques. In particular, Doppler radar methods are emerging as a means for remote sensing of respiration and heart activity, which until recently was restricted science fiction. The potential such nonintrusive accrual biomedical data applies wide range health/life applications motivated development wealth radio signal processing research. Notably, there been keen interest in addressing...
See-through-wall imaging radar is a unique application of ultra wideband communication that can provide soldiers and law enforcement officers with an enhanced situation awareness. We have developed ultra-wideband high-resolution short pulse system operating around 10 GHz, where two essential considerations are addressed: the effect penetrating walls; fidelity through UWB components antennas radar. Modeled measured wall parameters, antenna types on signal discussed in detail.
An accurate ultra wideband (UWB) localization approach has been developed based on time difference of arrival (TDOA). This method provides sub-cm accuracy, which is excellent for indoor utilization when compared with frequency modulated continuous wave (FMCW) systems. The system also in compliance FCC UWB regulations and achieves ranging measurements. utilized domain measurements suppress multipath signals have potential sub-mm resolution
In this paper, a novel ultra-wideband GCPW to SIW transition is developed. The integrates the coupling slot and impedance transformer into one tapered achieve an ultra wide bandwidth. converts arbitrary of port impedance. vias were strategically located suppress unwanted modes across as well. fabricated demonstrated over 10 GHz bandwidth with less than 0.4 dB insertion loss at X-band. Theoretical experimental results are presented compared previously designed transitions.
The substrate-integrated waveguide (SIW) technology is utilized as an alternative low-cost approach in fabricating cavity-backed patch antennas. proposed antenna arrays combine the attractive features of conventional metalized like surface wave suppression, high radiation efficiency, and enhanced bandwidth, yet provide a low manufacturing cost. A previously developed design 2×2 SIW microstrip sub-array extended here used basic building block to attain larger 2 × 4, 4 8 elements. fabricated...
A class of wide-scan angle wide-band microstrip patch phased arrays is proposed. The proposed are composed probe-fed patches backed by substrate-integrated cavities. First, a simplified 2-D numerical analysis based on Floquet's theorem presented to qualitatively demonstrate the E-plane scan performance cavity-backed structure compared that conventional array. Second, 3-D thoroughly investigated varying both substrate thickness and dielectric constant using commercially available EM...
Pulse Doppler radars using UWB technology are becoming very popular for their wide range of capabilities and applications. waveforms used imaging in indoor environments, target localization classification behind walls, evaluating micro-Doppler signatures. pulse provide range-time-frequency representation that provides both highly accurate information. This is detailed human gait analysis, tracking more than one subject even respiration rate detection moving subjects. That can be useful...