Marco Mercuri

Dual-Band Planar Bowtie Monopole for a Fall-Detection Radar and Telemetry System

A dual-band planar bowtie monopole for a fall-detection radar and telemetry system is presented. Unidirectionality is successfully enabled by a full ground plane. A compact radiator footprint is achieved by closely spacing two bowtie elements for transmit-receive operation, combined with a simple and effective technique for mutual-coupling reduction. The radar antenna shows target location and speed detection capabilities of up to 4 m with resolution of 30 cm and fall-detection success rate of 95%. Its telemetry capability is then validated practically by frame transmissions through this antenna, which are successfully received by a base station located 5 m away.

Real-time fall detection and tagless localization using radar techniques

The senior citizen population older than 60 years has been steadily increasing worldwide. Due to this evolution, healthcare is now a major point of attention in the entire world. In particular, falling represents the major risk for elderly people who live independently. In the last two decades, innovative technological approaches have been investigated aiming at human-being long-term monitoring. However, current solutions suffer from critical limitations in real-case situations. In this paper, a complete radar-based system for concurrent real-time contactless fall detection and tagless localization in a real in-door environment is presented and discussed. Experimental tests, conducted on persons in a real room setting, have demonstrated the feasibility of this approach showing an adequate detection of the persons absolute distance and a success rate to detect fall events of 100% with a maximum delay of about 316 ms. In addition to that, no false positives have been reported.

Dual-mode wireless sensor network for real-time contactless in-door health monitoring

Due to the ageing population, real-time and autonomous health monitoring is an emerging priority in ambient assisted living. In this work, a wireless sensor network is proposed for home environments by which the sensors are dualmode radars, enabling concurrent remote localization of a person (i.e., without use of a tag) and fall detection. We elaborate on the network architecture, and in particular on the signaling as to enable real-time data processing (i.e., max. delay is 0.3 s) combined with radar-based wireless sensing. The approach is successfully demonstrated experimentally.

Radar-Based Health Monitoring

Radar techniques aiming at health monitoring have been investigated in recent years. The possibility of contactless monitoring human individuals has aroused interest in many applications especially where the use of wearable sensors generates discomfort which not only may affect the results but also imposes a risk factor. Radar technologies represent therefore the new emerging solution to promote the well-being of elderly people both in home and clinical environments. This paper provides an overview on recent advances in health monitoring using radar techniques. Moreover, an example of a concrete health monitoring system is also reported.

Wireless health monitoring: Design challenges

The elderly population has been steadily increasing worldwide. This situation has resulted in a growing need for healthcare approaches that emphasize routine long-term monitoring. Monitoring is of primary interest in the home situation in cultures where elderly do not live with relatives. In recent years, wireless technologies have been investigated aiming at health monitoring. They represent the key to improve person care, chronic disease management, and to promote the well-being of aged persons, allowing them to enlarge the period of living in their familiar home environment. This paper discusses recent advances in health monitoring using wireless technologies, presenting design challenges, practical limitations, and solutions.

Monostatic continuous-wave radar integrating a tunable wideband leakage canceler for indoor tagless localization

Continuous-wave (CW) radars have been recently investigated in healthcare aiming at contactless health monitoring. However, a major problem in monostatic CW architectures is represented by the unwanted leakage produced by poor isolation between transmitter and receiver, which can drastically decrease the receivers sensitivity reducing therefore the radar dynamic range. Although this situation can be easily controlled in case of narrowband CW radar by an appropriate passive microwave design, it becomes much more complicated in case of stepped-frequency CW and frequency-modulated CW architectures that present an ultra-wideband nature. In this paper, a monostatic CW radar integrating a tunable wideband leakage canceler aiming at indoor tagless localization is presented and discussed. The use of the feedforward canceler allows a strong reduction of the unwanted leakage over the whole radar bandwidth. Experimental results demonstrate the feasibility of this approach, showing an outstanding improvement of the radar dynamic range.

Healthcare System for Non-invasive Fall Detection in Indoor Environment

Fall incidents and the sustained injuries represent the main causes of accidents for elderly people, and also the third cause of chronic disability. The rapid detection of a fall event can reduce the mortality risk, avoiding also the aggravation of injuries. In this paper an embedded healthcare system based on a microwave radar is presented. A Continuous Wave (CW) Doppler radar is used to detect the changes in speed of different persons experienced during daily activities, namely falling and normal/random movements. The resulted speed signals are then processed in real-time by a digital signal processor (DSP) in order to detect fall incidents. Experimental results, conducted on real human volunteers in a real room setting, have shown a success rate of 100 % in detecting fall events. Moreover, no false positives have been reported.

Contactless medical sensing

Radar technologies are emerging for health monitoring. The possibility of characterizing speed and distance in a contactless way opens up a range of practical applications, such as allowing elderly to reside longer in their familiar environment. Research has been focusing at first at single radar solutions targeting vital signs monitoring and detection of falls. Over time, these speed based parameters got combined with in-door localisation as well. To increase flexibility further, recent developments evolve towards wireless radar sensor networks. In this overview paper, the state-of-art is illustrated by means of various practical examples.

A practical distance measurement improvement technique for a SFCW-based health monitoring radar

A technique in improving the distance measurement of an indoor Stepped-Frequency Continuous Wave (SFCW) radar is proposed and presented in this work. The main objective of this SFCW radar is to enable a non-invasive way in measuring the location of patients in a home environment without the need for a worn geo-locating tag. The theoretical and practical operation principle of the radar setup is first explained. Due to its operation in an indoor environment using a twoantenna setup, reflections, multipath, backscattering and crosscoupling are expected to affect its localization estimation. Thus a compensation technique based on Inverse Fast Fourier Transform (IFFT) is used to overcome this limitation. Practical measurements conducted in a 5 x 5 m2 room have successfully proven that the approach is able to compensate for practical multipath from walls, furniture and metallic shelves, yielding a distinct improved measurement technique in localizing a person in a real indoor environment.

Design and evaluation of dual-band antennas aimed for contactless health monitoring radar

This paper presents the evaluation of two antenna designs aimed for a Step Frequency Continuous Wave (SFCW) radar capable of non-invasive fall detection in a pseudo-static radar configuration. The performance of a dual-band rectangular planar monopole is compared against a conductor-backed coplanar waveguide (CBCPW) fed bowtie slot antenna in free space. Two elements of the better performing CBCPW fed bowtie antenna are then combined, separated by a metal plate, and evaluated on the level of SFCW radar operation. It is shown that the performance of the novel CBCPW fed bowtie slot antenna is superior compared to the rectangular planar monopole antenna in terms of person scanning capability.