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Special Issue "Ultra Wideband (UWB) Systems in Biomedical Sensing"

A special issue of Sensors (ISSN 1424-8220). This special issue belongs to the section "Biomedical Sensors".

Deadline for manuscript submissions: 15 December 2021.

Special Issue Editor

Prof. Dr. Mohammad Ghavami
E-Mail Website
Guest Editor
London South Bank University, 103 Borough Rd, London SE1 0AA, UK
Interests: ultra-wideband technology; biomedical applications of wireless systems; smart antenna signal processing; sensor networks

Special Issue Information

Dear Colleagues,

UWB radar is a new and powerful tool for non-invasive and non-intrusive measurements based on microwave electromagnetic fields and signal processing. Sensors with this technology are used for both short- and long-term monitoring and surveillance measurements exploiting remote sensing methodologies.

This Special Issue on UWB Systems in Biomedical Sensing invites unpublished papers exploring recent advances and developments in healthcare applications of UWB bioengineering measurement devices and related electronic implementation. This issue accepts both high-quality articles containing original research results and review articles and will allow readers to learn more about the potentials of UWB sensors in bioengineering devices.

Prospective authors are invited to submit unpublished work on the following research topics related to this Special Issue:

  • Wearable UWB sensors and devices;
  • UWB radar in medical physics;
  • Ultra-wideband biosensing and biosignal analysis and processing;
  • Microwave healthcare information systems and health informatics;
  • UWB system electronics for healthcare applications;
  • UWB cancer detection and imaging;
  • UWB sensors for detection of heart rate, respiratory movements, and human gate analysis;
  • UWB positioning radar for fall detection and activity monitoring of elderly and patients;
  • UWB in biomedical treatment;
  • UWB in wireless power transmission and harvesting;
  • UWB sensor materials, properties, concepts, fabrication, and testing techniques;
  • Application-oriented UWB printed sensor systems.

Prof. Mohammad Ghavami
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Sensors is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Ultra-wideband technology
  • UWB wireles sensors
  • Biomedical applications
  • Wearable and portable medical devices
  • Wireless sensor networks
  • Patient remote monitoring
  • UWB imaging
  • UWB medical electronics
  • Futuristic healthcare methodologies

Published Papers (7 papers)

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Research

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Article
Validation of a New Contactless and Continuous Respiratory Rate Monitoring Device Based on Ultra-Wideband Radar Technology
Sensors 2021, 21(12), 4027; https://doi.org/10.3390/s21124027 - 11 Jun 2021
Viewed by 370
Abstract
Respiratory rate (RR) is typically the first vital sign to change when a patient decompensates. Despite this, RR is often monitored infrequently and inaccurately. The Circadia Contactless Breathing Monitor™ (model C100) is a novel device that uses ultra-wideband radar to monitor RR continuously [...] Read more.
Respiratory rate (RR) is typically the first vital sign to change when a patient decompensates. Despite this, RR is often monitored infrequently and inaccurately. The Circadia Contactless Breathing Monitor™ (model C100) is a novel device that uses ultra-wideband radar to monitor RR continuously and un-obtrusively. Performance of the Circadia Monitor was assessed by direct comparison to manually scored reference data. Data were collected across a range of clinical and non-clinical settings, considering a broad range of user characteristics and use cases, in a total of 50 subjects. Bland–Altman analysis showed high agreement with the gold standard reference for all study data, and agreement fell within the predefined acceptance criteria of ±5 breaths per minute (BrPM). The 95% limits of agreement were −3.0 to 1.3 BrPM for a nonprobability sample of subjects while awake, −2.3 to 1.7 BrPM for a clinical sample of subjects while asleep, and −1.2 to 0.7 BrPM for a sample of healthy subjects while asleep. Accuracy rate, using an error margin of ±2 BrPM, was found to be 90% or higher. Results demonstrate that the Circadia Monitor can effectively and efficiently be used for accurate spot measurements and continuous bedside monitoring of RR in low acuity settings, such as the nursing home or hospital ward, or for remote patient monitoring. Full article
(This article belongs to the Special Issue Ultra Wideband (UWB) Systems in Biomedical Sensing)
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Article
Ultra-Wideband Radar-Based Indoor Activity Monitoring for Elderly Care
Sensors 2021, 21(9), 3158; https://doi.org/10.3390/s21093158 - 02 May 2021
Viewed by 444
Abstract
In this paper, we propose an unobtrusive method and architecture for monitoring a person’s presence and collecting his/her health-related parameters simultaneously in a home environment. The system is based on using a single ultra-wideband (UWB) impulse-radar as a sensing device. Using UWB radars, [...] Read more.
In this paper, we propose an unobtrusive method and architecture for monitoring a person’s presence and collecting his/her health-related parameters simultaneously in a home environment. The system is based on using a single ultra-wideband (UWB) impulse-radar as a sensing device. Using UWB radars, we aim to recognize a person and some preselected movements without camera-type monitoring. Via the experimental work, we have also demonstrated that, by using a UWB signal, it is possible to detect small chest movements remotely to recognize coughing, for example. In addition, based on statistical data analysis, a person’s posture in a room can be recognized in a steady situation. In addition, we implemented a machine learning technique (k-nearest neighbour) to automatically classify a static posture using UWB radar data. Skewness, kurtosis and received power are used in posture classification during the postprocessing. The classification accuracy achieved is more than 99%. In this paper, we also present reliability and fault tolerance analyses for three kinds of UWB radar network architectures to point out the weakest item in the installation. This information is highly important in the system’s implementation. Full article
(This article belongs to the Special Issue Ultra Wideband (UWB) Systems in Biomedical Sensing)
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Article
Brachialis Pulse Wave Measurements with Ultra-Wide Band and Continuous Wave Radar, Photoplethysmography and Ultrasonic Doppler Sensors
Sensors 2021, 21(1), 165; https://doi.org/10.3390/s21010165 - 29 Dec 2020
Viewed by 576
Abstract
The measurement and analysis of the arterial pulse wave provides information about the state of vascular health. When measuring blood pressure according to Riva-Rocci, the systolic and diastolic blood pressure is measured non-invasively with an inflatable pressure cuff on the upper arm. Today’s [...] Read more.
The measurement and analysis of the arterial pulse wave provides information about the state of vascular health. When measuring blood pressure according to Riva-Rocci, the systolic and diastolic blood pressure is measured non-invasively with an inflatable pressure cuff on the upper arm. Today’s blood pressure monitors analyze the pulse wave in reference to the rising or falling cuff pressure. With the help of additional pulse wave analysis, one can determine the pulse rate and the heart rate variability. In this paper, we investigated the concept, the construction, and the limitations of ultrawideband (UWB) radar and continuous wave (CW) radar, which provide continuous and non-invasive pulse wave measurements. We integrated the sensors into a complete measurement system. We measured the pulse wave of the cuff pressure, the radar sensor (both UWB and CW), the optical sensor, and ultrasonic Doppler as a reference. We discussed the results and the sensor characteristics. The main conclusion was that the resolution of the pulse radar was too low, even with a maximum bandwidth of 10 GHz, to measure pulse waves reliably. The continuous wave radar provides promising results for a phantom if adjusted properly with phase shifts and frequency. In the future, we intend to develop a CW radar solution with frequency adaption. Full article
(This article belongs to the Special Issue Ultra Wideband (UWB) Systems in Biomedical Sensing)
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Article
Developing Artefact Removal Algorithms to Process Data from a Microwave Imaging Device for Haemorrhagic Stroke Detection
Sensors 2020, 20(19), 5545; https://doi.org/10.3390/s20195545 - 28 Sep 2020
Viewed by 860
Abstract
In this paper, we present an investigation of different artefact removal methods for ultra-wideband Microwave Imaging (MWI) to evaluate and quantify current methods in a real environment through measurements using an MWI device. The MWI device measures the scattered signals in a multi-bistatic [...] Read more.
In this paper, we present an investigation of different artefact removal methods for ultra-wideband Microwave Imaging (MWI) to evaluate and quantify current methods in a real environment through measurements using an MWI device. The MWI device measures the scattered signals in a multi-bistatic fashion and employs an imaging procedure based on Huygens principle. A simple two-layered phantom mimicking human head tissue is realised, applying a cylindrically shaped inclusion to emulate brain haemorrhage. Detection has been successfully achieved using the superimposition of five transmitter triplet positions, after applying different artefact removal methods, with the inclusion positioned at 0°, 90°, 180°, and 270°. The different artifact removal methods have been proposed for comparison to improve the stroke detection process. To provide a valid comparison between these methods, image quantification metrics are presented. An “ideal/reference” image is used to compare the artefact removal methods. Moreover, the quantification of artefact removal procedures through measurements using MWI device is performed. Full article
(This article belongs to the Special Issue Ultra Wideband (UWB) Systems in Biomedical Sensing)
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Article
Investigation of an Ultra Wideband Noise Sensor for Health Monitoring
Sensors 2020, 20(4), 1034; https://doi.org/10.3390/s20041034 - 14 Feb 2020
Viewed by 924
Abstract
Quick on-scene assessment and early intervention is the key to reduce the mortality of stroke and trauma patients, and it is highly desirable to develop ambulance-based diagnostic and monitoring devices in order to provide additional support to the medical personnel. We developed a [...] Read more.
Quick on-scene assessment and early intervention is the key to reduce the mortality of stroke and trauma patients, and it is highly desirable to develop ambulance-based diagnostic and monitoring devices in order to provide additional support to the medical personnel. We developed a compact and low cost ultra wideband noise sensor for medical diagnostics and vital sign monitoring in pre-hospital settings. In this work, we demonstrated the functionality of the sensor for respiration and heartbeat monitoring. In the test, metronome was used to manipulate the breathing pattern and the heartbeat rate reference was obtained with a commercial electrocardiogram (ECG) device. With seventeen tests performed for respiration rate detection, sixteen of them were successfully detected. The results also show that it is possible to detect the heartbeat rate accurately with the developed sensor. Full article
(This article belongs to the Special Issue Ultra Wideband (UWB) Systems in Biomedical Sensing)
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Article
High Efficient and Ultra Wide Band Monopole Antenna for Microwave Imaging and Communication Applications
Sensors 2020, 20(1), 115; https://doi.org/10.3390/s20010115 - 23 Dec 2019
Cited by 10 | Viewed by 1252
Abstract
The paper presents a highly efficient, low cost, ultra-wideband, microstrip monopole antenna for microwave imaging and wireless communications applications. A new structure (z-shape, ultra-wideband (UWB) monopole) is designed, which consists of stepped meander lines to achieve super-wide bandwidth and high efficiency. Three steps [...] Read more.
The paper presents a highly efficient, low cost, ultra-wideband, microstrip monopole antenna for microwave imaging and wireless communications applications. A new structure (z-shape, ultra-wideband (UWB) monopole) is designed, which consists of stepped meander lines to achieve super-wide bandwidth and high efficiency. Three steps are used to design the proposed structure for the purpose to achieve high efficiency and wide bandwidth. The antenna bandwidth is enhanced by varying the length of meander line slots, optimization of the feeding line and with the miniaturization of the ground width. The simulated and measured frequency bands are 2.7–22.5 GHz and 2.8–22.7 GHz (156% fractional bandwidth), respectively. The dimensions of the antenna are 38 mm × 35 mm × 1.57 mm, and its corresponding electrical size is 2.41 λg × 2.22 λg × 0.09 λg, where guided wavelength λg is at the center frequency (12.75 GHz). This antenna achieved a high bandwidth ratio (8.33:1). The realized gain is varying from 1.6–6.4 dBi, while that of efficiency is 70% to 93% for the whole band. Radiation patterns are measured at four operating frequencies. It has an acceptable group delay, fidelity factor, and phase variation results that satisfy the limit of ultra-wideband in the form of the time domain. Full article
(This article belongs to the Special Issue Ultra Wideband (UWB) Systems in Biomedical Sensing)
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Other

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Letter
Time-Domain Investigation of Switchable Filter Wide-Band Antenna for Microwave Breast Imaging
Sensors 2020, 20(15), 4302; https://doi.org/10.3390/s20154302 - 01 Aug 2020
Cited by 4 | Viewed by 946
Abstract
This paper investigates the time-domain performance of a switchable filter impulse radio ultra-wideband (IR-UWB) antenna for microwave breast imaging applications. A miniaturized CPW-fed integrated filter antenna with switchable performance in the range of the Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local [...] Read more.
This paper investigates the time-domain performance of a switchable filter impulse radio ultra-wideband (IR-UWB) antenna for microwave breast imaging applications. A miniaturized CPW-fed integrated filter antenna with switchable performance in the range of the Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN) bands could operate well within a 3.0 to 11 GHz frequency range. The time-domain performance of the filter antenna was investigated in comparison to that of the designed reference wideband antenna. By comparing both antennas’ time-domain characteristics, it was seen that the switchable filter antenna had good time-domain resolution along with the frequency-domain operation. Additionally, the time-domain investigation revealed that the switchable filter wide-band antenna performed similarly to the reference wide band antenna. This antenna was also utilized for a tumor detection application, and it was seen that the switchable filter wide-band antenna could detect a miniaturized irregularly shaped tumor easily, which is quite promising. Such an antenna with a good time-domain resolution and tumor detection capability will be a good candidate and will find potential applications in microwave breast imaging. Full article
(This article belongs to the Special Issue Ultra Wideband (UWB) Systems in Biomedical Sensing)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

1-Investigation of Differential Ultra-Wideband Microwave Imaging for Intracranial Hemorrhage Detection in Realized Full Head Phantom

Mohammad Ojaroudi1,2 and Stéphane Bila1
1 XLIM, UMR no7252, University of Limoges/CNRS, 123 Av. Albert Thomas, 87060 Limoges, France
2 Inria Lille-Nord Europe/FUN, 59650 Villeneuve D’Ascq, France; [email protected]
e-mail: [email protected], [email protected]

Abstract— In this paper, an ultra-wideband (UWB) mono-static microwave imaging system using a novel design of UWB tapered slot antenna (TSA) and full head phantom is employed to extract intracranial hemorrhage information of the human full head phantom with an injury target. In this study, to implement the differential microwave brain imaging system using vector network analyzer at the first step we present a modified UWB-TSA which provides a wide usable fractional bandwidth from 1.57 GHz to 7.04 GHz. The main purpose of this paper is employing a new image reconstruction technique for 2D visualization of time-domain results to extract intracranial hemorrhage information of from a full head phantom during brain injury. In order to reach this goal the advantages of generating a novel confocal image reconstructing algorithm based on combination of back-projection (BP) method and delay and some (DAS) beamforming will be employed. In addition, a novel hierarchical calibration method based on delay-multiply and sum (DMAS) is employed to improve the accuracy reconstructed image results. This calibration includes all delays of antenna array to put more energy at coherence reflected signal integration. Hence, stronger signals are available to achieve higher accuracy for precise spatial localization. The advantage conferred by “high resolution imaging” is that more energy is use at reflected signal than with conventional confocal imaging, subsequently a relatively higher resolution in identifying the reflected signal is achieved. Measured results using vector network analyzer shows the proposed method is valid for precisely calculating the time-dependent location of intracranial hemorrhage targets.
Index Terms—Differential Microwave Imaging System (DMIS), Ultra-Wideband Tapered-Slot Antenna (UWB-TSA), Confocal Image Reconctruction Algorithm, Intracranial Injury Detection, Delay And Some (DAS), delay-multiply and sum (DMAS).

2-A Novel Design of Miniaturized UWB/WLAN Antenna, for Intra-Brain Communication Applications

Mohammad Ojaroudi1,2 and Stéphane Bila1
1 XLIM, UMR no7252, University of Limoges/CNRS, 123 Av. Albert Thomas, 87060 Limoges, France
2 Inria Lille-Nord Europe/FUN, 59650 Villeneuve D’Ascq, France; [email protected]
e-mail: [email protected], [email protected]

Abstract— In this paper, a compact mono-static microwave imaging system using a novel design of ultra-wideband (UWB) tapered slot antenna (TSA) is employed to extract anatomical structure of the realized full head phantom. The proposed experimental setup includes vector network analyzer (VNA), precisely realized human head phantom and a modified UWB Tapered Slot Antenna (TSA), which provides a wide usable fractional bandwidth from 1.57 to over 7.04 GHz. The main purpose of this paper is employing a new image reconstruction technique to extract anatomical information of from a full head phantom for 2D visualization of time-domain results. In order to reconstruct image from the head phantom two different image reconstruction methods are compared. First, a conventional confocal method using delay and sum (DAS) beamforming is applied. Then, the advantages of generating a new image reconstructing algorithm based on combination of back-projection and time domain reflectometry methods is analyzed. The advantage conferred by “TDR based imaging algorithm” is that more energy in of reflected signals is used at phantom's layer, than with conventional confocal imaging, subsequently a relatively higher resolution in extracting the anatomical information is achieved. Measured results using experimental setup and reconstructed images from both algorithms are presented to validate the effectiveness of the proposed method for precisely calculating the time-dependent location of head's anatomy.
Index Terms—Microwave Near-Field Imaging System, Time-Domain Reflectometry (TDR), Confocal Image Reconctruction Algorithm, Anatomical Information Extraction.

3-A Novel Design of Miniaturized UWB/WLAN Antenna, for Intra-Brain Communication Applications

Mohammad Ojaroudi1.2*, Stéphane Bila1, and Mahdi Salimi3
1 XLIM, UMR no7252, University of Limoges/CNRS, 123 Av. Albert Thomas, 87060 Limoges, France
2 Inria Lille-Nord Europe/FUN, 59650 Villeneuve D’Ascq, France; [email protected]
3 Department of Biomedical Engineering, Gazi University, Ankara, Turkey
e-mail: [email protected], [email protected]

Abstract ─ A depiction of a novel multi-band printed monopole antenna, for intra-brain communication (IBCOM) utilization, by the ground on defected ground plane and radiating patch with slit and parasitic structures. The proposed structure consists a rectangular radiating patch with an L-shaped slit and parasitic structures and a ground plane with a T-shaped slits for satisfying UWB/WLAN requirements with a usable fractional bandwidth of a more than 100% (3.48-10.63 GHz). By inserting an L-shaped slot on the radiating patch’s corner, additional resonance is excited and much wider impedance bandwidth can be produced. In addition, a parasitic structure stated in the corner of the radiating patch with a L-folded-strip parasitic structure, which dispenses a wide-narrow bandwidth around 2.4 GHz. Inserting this parasitic structure created ability of the antenna to resonate in 2.4 lower frequency band in order to carry on controlling command in IBCOM application. In order to manifest the usefulness of the brought antenna for the IBCOM applications, the SAR distribution employing an implanted antenna in the full head voxel model and external antenna is accorded. The proposed antenna exhibits very low SAR (<0.2 W/Kg), high fidelity (>71%) and almost omnidirectional radiation patterns over whole band.
Index Terms ─ Intra-Brain Communication (IBCOM), Closed-Loop Cortical Neuromodulation (CLCN), Ultra-Wideband Brain-Machine Interface (UWB-BMI), Printed Monopole Antenna, Inverted L-shaped Slit, Inverted L-Shaped Parasitic Structure.

4-Brachialis pulse wave measurement with ultra-wide band and continuous wave Radar, photoplethysmography and ultrasonic Doppler sensors


The measurement and analysis of the arterial pulse wave provides information about the state of the vascular health. When measuring blood pressure according to Riva-Rocci, the systolic and diastolic blood pressure is measured non-invasively with an inflatable pressure cuff on the upper arm. Today's blood pressure monitors analyze the pulse wave in reference to the rising or falling cuff pressure. With the help of pulse wave analysis, the pulse rate, the heart rate variability and others can be determined, which in connection with the measured blood pressure provide important additional information on the health of the circulatory system. We show the concept, the construction and the limitations of the UWB radar and CW radar by comparison. We describe the integration of the sensors into an overall system. We show the pulse wave of the cuff pressure, the radar sensor (both UWB and CW), the optical sensor and Doppler ultrasound in the time and frequency domain. We conclude with a comparison of the sensor results.

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