A5018226176- Microwave Engineering and Waveguides
- Radio Frequency Integrated Circuit Design
- Advanced Antenna and Metasurface Technologies
- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Electromagnetic Compatibility and Noise Suppression
- Microwave and Dielectric Measurement Techniques
- Antenna Design and Analysis
- Acoustic Wave Resonator Technologies
- Advanced Power Amplifier Design
- 3D IC and TSV technologies
- Terahertz technology and applications
- Millimeter-Wave Propagation and Modeling
- Semiconductor Quantum Structures and Devices
- Superconducting and THz Device Technology
- Gyrotron and Vacuum Electronics Research
- Advancements in PLL and VCO Technologies
- Electrical and Thermal Properties of Materials
- Energy Harvesting in Wireless Networks
- Electromagnetic Simulation and Numerical Methods
- Advanced MEMS and NEMS Technologies
- Advanced Photonic Communication Systems
- Semiconductor materials and interfaces
- Full-Duplex Wireless Communications
- Antenna Design and Optimization
University of Leeds
2016-2025
Physical Sciences (United States)
2023
ORCID
2021
COMSATS University Islamabad
2021
PerkinElmer (United Kingdom)
2020
University of Surrey
1996-2006
Universiti Sains Islam Malaysia
2006
University of London
1991-2005
King's College London
1992-2005
Mahanakorn University of Technology
2005
A technique for designing impedance-transforming baluns is presented in this paper. It based on the Marchand balun with two identical coupled lines. By varying coupling factor of sections, a wide range impedance transforming ratios can be achieved. In addition, resistive network added between outputs proposed to achieve output matching and isolation. Microstrip baluns, matched at all ports, from 50-/spl Omega/ source 40-/spl as well 160-/spl load terminations are realized demonstrate technique.
Abstract Robotics and autonomous systems are reshaping the world, changing healthcare, food production biodiversity management. While they will play a fundamental role in delivering UN Sustainable Development Goals, associated opportunities threats yet to be considered systematically. We report on horizon scan evaluating robotics impact all involving 102 experts from around world. likely transform how Goals achieved, through replacing supporting human activities, fostering innovation,...
Abstract Reconfigurable intelligent surfaces (RISs) are envisioned to transform the propagation space into a smart radio environment (SRE) realize diverse applications of sixth‐generation (6G) wireless communication. By smartly tuning massive number elements via controller, an RIS can passively phase‐shift electromagnetic (EM) waves enhance system performance. The absence radio‐frequency (RF) chains makes energy‐efficient and cost‐effective solution for future networks. In this paper,...
A new method of realising RF barcodes is presented using arrays identical microstrip dipoles capacitively tuned to be resonant at different frequencies within the desired licensed-free ISM bands. When interrogated, reader detects each dipole's resonance frequency and with n dipoles, potentially 2/sup n/-1 items in field can tagged identified. Results for barcode elements 5.8 GHz band are presented. It shown that accurate centre prediction by operating over multiple other license-exempt...
The synthesis and realization of an analog-phase shifter, delay line, attenuator, group synthesizer-are presented. These variable control devices are all implemented using the same generic single stage reflection topology. optimum conditions operation have been determined corresponding behaviors investigated to produce simple design equations. As proof-of-concepts, monolithic technology has used realize X-band, phase attenuator. Hybrid L-band, group-delay synthesizer. Because high levels...
This paper presents the design and fabrication of substrate-integrated waveguides filters for use at millimeter-wave frequencies. The components described are fabricated using photoimageable thick-film materials. Measurements on V- W-band waveguide-to-microstrip transitions presented. Losses resulting from reduced-height nature extracted thru-relect-line calibration standards illustrating effect current losses in broadwalls waveguides. fourth-order 0.01-dB ripple Chebyshev resonant cavity...
Two novel approaches are proposed here to achieve a practical RF barcode. Firstly, useful number of bits the resonator centre frequencies span three bands: 2.4GHz, 5.25GHz and 5.8GHz. Secondly, width variation is used for fine control barcode resonance frequency within <0.2% accuracy. Bistatic S21 based detection on scattering absorption interrogate barcodes in field 5 bit operation demonstrated successfully 5470- 5875 MHz band at 1.5m range. Similarities differences between selective...
A novel microfluidic-integrated microwave sensor with potential application in microliter-volume biological/ biomedical liquid sample characterization and quantification is presented this paper. The designed based on the resonance method, providing best sensing accuracy, implemented by using a substrate-integrated-waveguide (SIW) structure combining rectangular slot antenna operating at 10 GHz. device can perform accurate of various materials from very low to high loss, demonstrated...
This paper reports on the design and three-dimensional (3D) integration of low-cost, low-loss easy-to-fabricate 3D-printed integrated lens antennas (ILAs) for 5G broadband wireless communications in 28 GHz frequency range. The ILA designs consist an extended hemispherical lens, fed by two different types source antennas, a substrate waveguide (SIW) slot antenna array microstrip patch (MPA) array. Results from comprehensive parametric analyses infill pattern density 3D printed dielectric...
In this paper, a novel and innovative approach to characterize THz Bragg fibers using horn-type adapter is presented, enabling two-tier calibration method for direct, efficient, reliable way measure fibers, including return loss insertion loss. The proposed robust, accurate, repeatable, making it suitable designing optimizing systems continued research development. present study employs approach, utilizing Short-Short-Load-Thru (SSLT) Thru-Reflect-Line (TRL) calibrations. connects standard...
A network that synthesises negative group delay is presented. The conditions required for achieving delay, with a simple R–L–C tuned circuit, are briefly introduced. hybrid MIC realisation of the network, operating at 1 GHz, described and its measurements reported.
The analysis and design of a triple-band equal-split Wilkinson power divider are described. circuit proposed is well matched isolated at three arbitrary frequencies. procedure for the three-section transmission-line transformer based derived from ideal model provided. Simulated experimental results in microstrip technology presented to verify idea equations
A simple method using lumped inductors to compensate unequal even- and odd-mode phase velocities in parallel coupled microstrip lines is presented. The singly doubly compensated cases are analyzed enable the optimum inductor values electrical lengths of be calculated from closed-form expressions. technique proposed not only improves performance, but also yields a more compact design. To demonstrate technique's broad range applicability, coupled-line structure used enhance performance 900-MHz...
In this paper, a novel hollow substrate integrated waveguide (HSIW) is presented for realizing low-loss millimeter-wave (mm-wave) transmission lines embedded in multi-chip modules. A new analysis method the HSIW proposed by treating it as combination of two-dielectric loaded rectangular (RWG) and standard waveguide, where an effective dielectric constant, ε <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</sub> , introduced. An prototype...
In this paper, resin-based photocurable polymer materials for stereolithography, digital-light-processing (DLP), and polymer-jetting additive manufacturing techniques were characterized from 0.2 to 1.4 terahertz (THz) their comprehensive dielectric properties, e.g., refractive index, absorption coefficient, constant, loss tangent, by using laser-based THz time-domain spectroscopy. A total of 14 3D-printing polymers chosen, owing suitability, in terms printing resolution, material...
This work presents, for the first time, an in-situ self-aligned fluidic-integrated microwave sensor characterizing NaCl contents in NaCl-aqueous solution based on a 16-GHz bandpass combline cavity resonator. The discrimination of concentration is achievable by determining amplitude differences and resonant frequency translations between incident reflected signals at input terminal resonator capacitive loading effects comb structure inside introduced under test. Twelve liquid mixture samples...
Federated Learning (FL) presents a mechanism to allow decentralized training for machine learning (ML) models inherently enabling privacy preservation. The classical FL is implemented as client-server system, which known Centralised (CFL). There are challenges inherent in CFL since all participants need interact with central server resulting potential communication bottleneck and single point of failure. In addition, it difficult have some scenarios due the implementation cost complexity....
Computational biomechanical analysis plays a pivotal role in understanding and improving human movements physical functions. Although physics-based modeling methods can interpret the dynamic interaction between neural drive to muscle dynamics joint kinematics, they suffer from high computational latency. In recent years, data-driven have emerged as promising alternative due their fast execution speed, but label information is still required during training, which not easy acquire practice....
Accurate understanding of muscle activation and forces plays an essential role in neuro-rehabilitation musculoskeletal disorder treatments. Computational modeling has been widely used as a powerful non-invasive tool to estimate them through inverse dynamics using static optimization, but the inherent computational complexity results time-consuming analysis. In this paper, we propose knowledge-based deep learning framework for time-efficient dynamic analysis, which can predict from joint...
A tunable active inductor is presented where the novel topology enables both inductance and series resistance to be varied. With a discrete MMIC realization of this inductor, Q-factors in excess 15000 have been measured over wide range values. Applications for these inductors include high-performance narrow-band filters, voltage controlled oscillators, analog phase shifters. Analytical equations 3-resonator filter are given. The performance monolithic 2 GHz achieves mean insertion loss 0.9...
The importance of being able to design affordable, high-performance, millimeter-wave transmitters for digital communications and radar applications is increasing. To this end, two monolithic vector modulators have been realized at 38 60 GHz use in direct multilevel carrier modulation. It shown that, by employing balanced biphase amplitude modulator elements, accurate constellations are achieved with broad-band operation from 20 40 55 65 GHz. Modulations 16- 256-QAM demonstrated, both GHz,...
The design, fabrication and performance of a 60-GHz multi-chip module receiver employing substrate integrated waveguide filter antenna are presented. is onto single multilayer substrate, fabricated using photo-imageable thick-film technology. incorporates GaAs monolithic microwave circuit low-noise amplifier downconverter, with lumped elements for intermediate frequency (IF) filtering embedded into the substrate. chip cavities mounting MMICs photo-imaged as part standard process, giving...
This paper reports on a miniaturized lab-on-a-waveguide liquid-mixture sensor, achieving highly accurate nanoliter liquid sample characterization, for biomedical applications. The nanofluidic-integrated millimeter-wave sensor design is based near-field transmission-line technique implemented by single loop slot antenna operating at 91 GHz, fabricated into the lid of photolaser-based subtractive manufactured WR-10 rectangular waveguide. nanofluidic subsystem, which mounted top aperture, using...
This paper presents a 220-320-GHz hemispherical lens antenna fabricated using photopolymer-based additive manufacture and directly fed by the standard WR-3 rectangular waveguide without any additional extension. The microfabrication process is based on digital light processing rapid prototyping Monocure 3DR3582C resin-based photocurable polymer. gives various key advantages, including ease of fabrication, manufacturing speed, cost-effectiveness due to its fabrication capability. Even though...