Panagiotis Kosmas

King's College London | KCL · Department of Engineering

Precise and timely forecasting of blood glucose levels is essential for effective diabetes management. While extensive research has been conducted on Type 1 diabetes mellitus, Type 2 diabetes mellitus (T2DM) presents unique challenges due to its heterogeneity, underscoring the need for specialized blood glucose forecasting systems. This study intro...

Precise and timely forecasting of blood glucose levels is essential for effective diabetes management. While extensive research has been conducted on Type 1 diabetes mellitus, Type 2 diabetes mellitus (T2DM) presents unique challenges due to its heterogeneity, underscoring the need for specialized blood glucose forecasting systems. This study intro...

In this study, we present a non-invasive glucose prediction system that integrates Near-Infrared (NIR) spectroscopy and millimeter-wave (mm-wave) sensing. We employ a Mixed Linear Model (MixedLM) to analyze the association between mm-wave frequency S_21 parameters and blood glucose levels within a heterogeneous dataset. The MixedLM method considers...

This paper addresses the challenge posed by Motion-Induced Artifact (MIA) in surface electromyography (sEMG) signals, a prevalent issue in professional sports settings due to the movements and collisions of athletes. The shared frequency spectra and non-stationary characteristics of MIA and sEMG, coupled with the unpredictable and impulsive occurre...

Reconfigurable metasurfaces (RMTSs) are in high demand for advanced applications in 5G wireless communications thanks to their intriguing ability to control the electromagnetic (EM) response dynamically. However, most efforts so far have focused on modulating only either the EM wavefront amplitude or frequency. The key issue limiting the developmen...

Understanding the complex relationships of biomarkers in diabetes is pivotal for advancing treatment strategies, a pressing need in diabetes research. This study applies Bayesian network structure learning to analyze the Shanghai Type 1 and Type 2 diabetes mellitus datasets, revealing complex relationships among key diabetes-related biomarkers. The...

This mini-review examines the most prominent features and usages of metamaterials, such as metamaterial-based and metamaterial-inspired RF components used for biomedical applications. Emphasis is given to applications on sensing and imaging systems, wearable and implantable antennas for telemetry, and metamaterials used as flexible absorbers for pr...

sEMG-based motion classification, traditionally applied for hand gesture recognition in prosthetics, presents transformative potential in sports science. Its broader application, however, is limited by the lack of extensive sports-specific data. This study adopts a unique few-shot metric learning (FSL) framework using a laboratory-collected hand-ge...

Wearable, implantable, and ingestible antennas are continuously evolving in biomedical applications, as they are crucial components in devices used for monitoring and controlling physiological parameters. This work presents an experimentally validated wearable pad which can improve transmission of electromagnetic waves into the human body. This met...

p>This paper presents COZDAL (Convolutional Octave-band Zooming-in with Depth-kernel Attention Learning), a versatile deep-learning model designed for surface Electromyography (sEMG) motion classification. Specifically focusing on sports movements involving the hamstring muscle, the model employs attention mechanisms across various frequency bands,...

p>This paper presents COZDAL (Convolutional Octave-band Zooming-in with Depth-kernel Attention Learning), a versatile deep-learning model designed for surface Electromyography (sEMG) motion classification. Specifically focusing on sports movements involving the hamstring muscle, the model employs attention mechanisms across various frequency bands,...

Recently, great progress has been achieved in diabetes management through minimally invasive continuous glucose monitoring, which involves piercing the skin to identify changes in glucose levels in the interstitial fluid. Nevertheless, the development of accurate fully non-invasive glucose monitors remains a topic of great interest. This work exami...

Nowadays, medical imaging and healthcare in general are facing an ever growing number of challenges. Increase in life expectancy, for example, results in a growing economic cost of healthcare services. In particular, the need for medical imaging equipment worldwide is expected to grow driven by the global rise of various pathologies such as cancer,...

We assess the application of microwave tomography (MWT) for the detection of axillary lymph nodes (ALNs) in breast cancer patients. We numerically study the effects of limiting angular view in axillary MWT, as probes can only be placed on a limited arc around the axillary region. We also numerically study the possibility of increasing the amount of...

p> Motion classification with surface electromyog- raphy (sEMG) has been studied for practical applications in prosthesis limb control and human-machine interaction. Recent studies have shown that feature learning with deep neural networks (DNN) reaches considerable accuracy in motion classification tasks. However, DNNs require large datasets for...

p> Motion classification with surface electromyog- raphy (sEMG) has been studied for practical applications in prosthesis limb control and human-machine interaction. Recent studies have shown that feature learning with deep neural networks (DNN) reaches considerable accuracy in motion classification tasks. However, DNNs require large datasets for...

This paper presents COZDAL (Convolutional Octave-band Zooming-in with Depth-kernel Attention Learning), a versatile deep-learning model designed for surface Electromyography (sEMG) motion classification. Specifically focusing on sports movements involving the hamstring muscle, the model employs attention mechanisms across various frequency bands, k...

Surface electromyography (sEMG) provides physiological information that can be used in sports science. In many applications, sEMG signal activity, i.e., contractions, need to be detected in the stream of sensor recordings. During sports exercises, the impact of any collision on the body due to an athlete’s movement (e.g., jump) form an additive noi...

Measuring and reporting the dielectric properties of tissues remains a key area for microwave imaging and sensing, providing solid foundation for biomedical research in the field. In this study, the dielectric properties of tissues in athymic nude mice were evaluated. Measurements were conducted on liver, skin, muscle, and fat tissues using the co-...

In this paper, a hardware advancement for a microwave multi-static system for breast cancer detection is presented. In particular, we propose a metasurface-enhanced antenna capable of enhancing relevant "weak" signals backscattered by a tumour-mimicking target inserted in a breast phantom. Furthermore, we simulate a radar-based approach in CST Micr...

We present a preliminary study of microwave head imaging using a three-dimensional (3-D) implementation of the distorted Born iterative method (DBIM). Our aim is to examine the benefits of using the more computationally intensive 3-D implementation in scenarios where limited prior information is available, or when the target occupies an area that i...

We present an experimental validation of the distorted Born iterative method with the two-step iterative shrinkage thresholding (DBIM-TwIST) algorithm for the problem of brain stroke detection and differentiation, using an anatomically accurate, multi-layer head phantom. To this end, we have developed a gelatine-based, anatomically complex head pha...

Over the last two decades, metamaterials (MMs) and metasurfaces (MTSs) have been used to fabricate innovative antenna designs, offering cost-effective solutions compared to conventional radiating systems. This paper investigates the feasibility of combining MM design concepts and imaging techniques to create innovative microwave imaging systems. In...

This article presents an approach to enhance the detection of buried landmines by applying machine learning (ML) to signals from a nuclear quadrupole resonance (NQR) system. This custom-made, low-cost, and portable NQR system has been developed for deployment in humanitarian demining, where strong radio frequency (RF) interference and a low signal-...

In recent years, new microwave-based imaging, sensing and hyperthermia applications have emerged in the field of diagnostics and therapy. For diagnosis, this technology involves the application of low power microwaves, utilising contrast between the relative permittivity of tissues to identify pathologies. This contrast can be further enhanced thro...

We reported measurement results relating to non-invasive glucose sensing using a novel multiwavelength approach that combines radio frequency and near infrared signals in transmission through aqueous glucose-loaded solutions. Data were collected simultaneously in the 37–39 GHz and 900–1800 nm electromagnetic bands. We successfully detected changes...

This paper reports the development of a new composite material as a matching medium for medical microwave diagnostic systems, where maximizing the microwave energy that penetrates the interrogated tissue is critical for improving the quality of the diagnostic images. The proposed material has several advantages over what is commonly used in microwa...

Stroke is a very frequent disorder and one of the major leading causes of death and disability worldwide. Timely detection of stroke is essential in order to select and perform the correct treatment strategy. Thus, the use of an efficient imaging method for an early diagnosis of this syndrome could result in an increased survival’s rate. Nowadays,...

The distorted Born iterative method (DBIM) is widely used in microwave imaging to solve the electromagnetic inverse scattering problem iteratively based on the distorted Born approximation. Various methods are used for the forward solver in the DBIM to simulate wave propagation and scattering. In this paper, a new matrix building technique exploiti...

Nuclear quadrupole resonance (NQR) technology is a promising approach to detect so-called “minimum metal” landmines, as it can look directly for their explosive content. Conventional commercially available NQR devices, however, are large and expensive, and they require a transmitter power amplifier with a power generator, which is not suitable for...

Detecting changes in the dielectric properties of tissues at microwave frequencies can offer simple and cost effective tools for cancer detection. These changes can be enhanced by the use of nanoparticles (NPs) that are characterised by both increased tumour uptake and high dielectric constant. This paper presents a two-port experimental setup to a...

The use of microwave imaging for brain stroke detection has attracted growing interest in the past decade, inspired by the presence of differences in the dielectric properties of stroke and the surrounding brain tissues. This paper presents and discusses the reconstruction results from measurements on a 3D-printed anthropomorphic head model, contai...

This paper presents a feasibility study to enhance microwave imaging (MWI) for intracerebral haemorrhage (ICH) detection using an innovative metamaterial (MM) design. To this end, we simulate a radar-based approach in CST Microwave Studio and use a previously developed algorithm based on Huygens principle to produce images with and without the MM....

We present a radio-frequency-activated switching system that can automatically detune a metamaterial resonator to enhance magnetic resonance imaging (MRI) performance. Local sensitivity-enhancing metamaterials typically consist of resonant components, which means that the transmitted radio frequency field is spatially inhomogeneous. The switching s...

We present an initial experimental validation of a microwave tomography (MWT)prototype for brain stroke detection and classification using the distorted Born iterative method, two-step iterative shrinkage thresholding (DBIM-TwIST) algorithm. The validation study consists of first preparing and characterizing gel phantoms which mimic the structure and...

We present an approach to enhance microwave brain imaging with an innovative metamaterial (MM) planar design based on a cross-shaped split-ring resonator (SRR-CS). The proposed metasurface is incorporated in different setups, and its interaction with EM waves is studied both experimentally and by using CST Microwave Studio® and is compared to a "no...

Globally, strokes are the primary cause of adult disability and the second largest cause of death. Early detection is crucial for choosing the correct treatment strategy and increasing the rate of survival. Microwave imaging is renowned as an emerging non-invasive and non-ionising technology for a wide range of application areas. Microwave imaging'...

Electromagnetic (EM) biomedical sensors in the mm-wave frequency range must detect small changes in signals in the presence of tissues, which are correlated to a pathological condition. These signals, however, can suffer from artifacts due to complex EM wave interactions such as diffraction and surface wave propagation, which are often overlooked i...

Demining is a highly impactful but complex problem which requires considerable resources and time. Land mine detection is the most hazardous and time consuming of the tasks in the demining pipeline. Currently, the risk of landmines being present in an area is estimated on the basis of non-technical surveys which are expensive and slow. This paper p...

We present proof of concept experiment of a sensing method to detect skin hydration using a low-cost bio-impedance sensor. The sensing system is validated by testing its current output over frequencies between 1 kHz and 50 kHz and comparing measured values of impedance. A series of experiments with salt-water mixtures as well as a gelatin-based pha...

The investigation of variations in dielectric properties of blood based on its biochemical profile is important for determining the feasibility of developing electromagnetic non-invasive sensing systems for monitoring the levels of various metabolites in blood. In this paper, the real and imaginary parts of dielectric permittivity are measured as a...

Magnetic resonance imaging (MRI) is a widely used clinical tool for medical diagnosis and therapy. Several research studies focus on passively improving MRI sensitivity using high dielectric constant (HDC) materials and metamaterials. In this work, we investigate a new metasurface resonator which can enhance local transmit and receive efficiency in...

Iterative shrinkage thresholding algorithms have been proposed recently for various microwave imaging applications. This paper presents for the first time an implementation of non-linear microwave imaging via the distorted Born iterative method (DBIM) in conjunction with fast iterative shrinkage/thresholding (FISTA), which presents advantages over...

Landmines are a major problem of international concern and it is therefore crucial to detect them with high probability of success. Nuclear Quadrupole Resonance (NQR) is a radiofrequency spectroscopic technique where explosive substances can be detected through the application of AC magnetic field transmission pulses at particular resonant frequenc...

The continuous increase in global food consumption brings forward the need for constant development of technologies to enhance the existing quality assessment methods. Such enhancement can both increase the safety of the consumers and decrease the product wastage. In recent decades, microwave imaging has emerged as a promising non-invasive and non-...

The application of microwave technologies in medical imaging and diagnostics is an emerging topic within the electromagnetic (EM) engineering community [...]

Motion artifacts are a common source of noise in many commercial devices and measurement systems. They tend to adversely affect the information that is present in the signal of interest. These artifacts are often corrected using various post processing techniques, predominantly using signal processing means, after the measurement process is complet...

We present a first prototype of a wideband microwave tomography system with potential application to medical imaging. The system relies on a compact and robust printed monopole antenna which can operate in the 1.0–3.0 GHz range when fully immersed in commonly used coupling liquids, such as glycerine–water solutions. By simulating the proposed imagi...

Muscle fatigue detection and tracking has gained significant attention as the sports science and rehabilitation technologies developed. It is known that muscle fatigue can be evaluated through surface Electromyography (sEMG) sensors, which are portable, non-invasive and applicable for real-time systems. There are plenty of fatigue tracking algorith...

Interference cancelation is a very important aspect of Nuclear Quadrupole Resonance (NQR) signal detection, and can become really difficult when the interference is considerably time-varying. We propose a novel wavelets method to effectively remove (or reduce) time-varying interference in the data and facilitate a valid detection of the NQR signal....

This paper studies how limited information in data acquired by a wideband microwave tomography (MWT) system can affect the quality of reconstructed images. Limitations can arise from experimental errors, mismatch between the system and its model in the imaging algorithm, or losses in the immersion and coupling medium which are required to moderate...

Microwave imaging (MWI) and microwave ther-moacoustic imaging (MTAI) show great potential for early-stage breast tumor detection. MWI suffers from low spatial resolution for accurate diagnosis, while MTAI is unable to provide quantitative dielectric information and its image quality degrades due to acoustic heterogeneity of breast tissue. To compen...

The paper presents the first in vivo glucose monitoring animal study in a pig, which correlates radio frequency signal transmission changes with changes in blood glucose concentration in the 58–62 GHz frequency range. The presented non-invasive glucose sensing system consists of two opposite facing patch antennas sandwiching glucose-loaded samples....

Interference can be a huge challenge for Nuclear Quadrupole Resonance (NQR) signal detection in real life settings. The problem is particularly challenging when interference is strong around the resonant frequency band of the targeted NQR signal (to which we refer as the NQR band). This paper first proves the beamforming characteristics of a design...

This paper presents a preliminary study of the impact of potential contrast enhancing agents on a 2-port microwave imaging system. To this end, we have conducted microwave measurements inside a dual cylindrical tank, comprised of an outer and inner cylinder filled with high and low loss liquids, respectively. A third smaller cylinder inside the low...

Objective: This paper proposes a novel microwave imaging (MWI) multifrequency technique, which combines compressive sensing (CS) with the well-known distorted Born iterative method. CS strategies are emerging as a promising tool in MWI applications, which can improve reconstruction quality and/or reduce the number of data samples. Methods: The p...

Purpose: Microwave imaging/sensing is an emerging technology that shows potential for healthcare diagnostic applications, particularly in breast cancer detection. This technique estimates the anatomically variant dielectric properties of the breast. Similar to other imaging modalities, nanoparticles (NPs) could potentially be utilised as contrast...