Safa Salman

Pulmonary Edema Monitoring Sensor With Integrated Body-Area Network for Remote Medical Sensing

A wearable health monitoring sensor integrated with a body-area network is presented for the diagnosis of pulmonary edema. This sensor is composed of 17 electrodes with 16 ports in-between and is intended to be placed on the human chest to detect lung irregularities by measuring the lungs average dielectric permittivity in a non-invasive way. Specifically, the sensors active port is fed by a 40 MHz RF signal and its passive ports measure the corresponding amplitudes of the scattering parameters (S-parameters). The dielectric constant of the lung is then post-processed and expressed as a weighted sum of the S-parameters measured from each port. An important aspect of the sensor is the use of multiple electrodes which mitigates the effect of the outer layers (skin, fat and muscle) on the lungs permittivity. This allows for the characterization of deeper tissue layers. To validate the sensor, tissue-emulating gels were employed to mimic in-vivo tissues. Measurements of the lungs permittivity in both healthy and pulmonary edema states are carried out to validate the sensors efficacy. Using the proposed post processing technique, the calculated permittivity of the lung from the measured S-parameters demonstrated error less than 11% compared to the direct measured value. Concurrently, a medical sensing body-area network (MS-BAN) is also employed to provide for remote data transfer. Measured results via the MS-BAN are well matched to those obtained by direct measurement. Thus, the MS-BAN enables the proposed sensor with continuous and robust remote sensing capability.

Determining the Relative Permittivity of Deep Embedded Biological Tissues

Human tissue characterization, deep into the body, has been of interest for decades. X-rays are used for locating tumors. However, such surgery-free identification methods fail to verify whether tumors are benign or malignant without surgical extraction and testing of sample tissue. Moreover, X-ray scans do not allow for continuous time monitoring because frequent exposure to ionizing radiation and contrast agents is harmful to the human body. Probe methods do provide accurate approximation of the dielectric constant εr but requires direct access to the specimen, making them suitable only for in-vitro applications. On the other hand, while common wearable health monitoring systems are advantageous for everyday use, they are mainly focused on simple functions such as temperature, and heart rate monitoring.

A Wearable Wrap-Around Sensor for Monitoring Deep Tissue Electric Properties

A wearable wrap-around sensor is proposed for continuous measurement of the permittivity of biological tissues deep into the torso (specifically, lung, and heart). The sensor is composed of multiple electrodes (antennas), excited at a single low frequency. A postprocessing technique is applied to the scattering data received by the electrodes to extract the permittivity of the tissues. The extraction process, which suppresses interferences from skin, fat, muscle, and bone layers is important especially with the fact that electrical properties may deviate from one person to another. In addition, the physical layout of the sensor provides the means to excite specific segments in a manner that localizes the extracted dielectric constant. This capability can allow for rudimentary localized imaging of the torsos cross section and different regions of the body using a low-cost portable sensor.

Embroidered textiles for RF electronics and medical sensors

Flexible radio frequency (RF) electronics are essential components in realizing wearable and flexible electronic devices, including conformal antennas [1]. They are required to provide mechanical conformality and flexibility, excellent RF performance and yet comply with the current circuit fabrication technology based on traditional rigid and flat devices. Existing flexible circuits employ light-weight polymer substrates (such as polyimide and polyester films) that can be flexed and deformed under external stress. However, these substrates return to their original shape after the stress is released. To overcome this drawback, we recently developed conformal-flexible electronics based on conductive fibers and elastic polymer substrates. Conducting fibers offer the unique conformal capability, low profiles and operational efficiency when applied onto the objects [2],[3].

Broadband bowtie-shaped current sheet antenna array

In this paper, the concept of a current sheet array (CSA) is expanded to design a broadband bowtie-shaped antenna array. The present approach has the potential to achieve a 7∶1 bandwidth over the VHF and UHF frequency bands with wide-angle beam. A 3 by 3 array of overlapping bowtie-shaped elements, with center feeding, was simulated. Printing was carried out on both faces of the dielectric slab and kept at a defined distance from the ground plane. A selected design was fabricated and tested experimentally to verify the simulated results for concept validation.

Determining the relative permittivity of masses in the human body

This paper introduces a new method for in-vivo determination of the dielectric properties for embedded regions in human tissues. A surgery-free method is proposed for on-body monitoring system to evaluate the dielectric properties of internal body components (lung, heart etc) and to effectively determine irregularities in real-time. The method uses a set of electrodes at low frequencies (10MHz) to obtain data that can determine the underlying layered structure. By using multiple electrodes, the effects of outer layers (skin, fat and muscle), are suppressed allowing for the characterization of deeper dielectric layer. In this paper, we present a proof of concept based on simulations. experimental data will be presented at the conference.

Rudimentary deep tissue imaging through a wearable real-time monitoring system

We present a novel wearable monitoring system to image the dielectric properties of internal body tissues pixel-by-pixel, and effectively determine irregularities in real-time. The proposed system consists of a flexible wearable sensor and a dielectric constant extraction technique. A set of on-body electrodes is employed to obtain scattering parameters used to extract the electrical properties of the underlying tissues at 40 MHz. Preliminary results show that accuracies as high as 6.75% can be achieved. Using this sensor, tissue abnormalities can be identified unobtrusively for a wide range of applications.

An on-body wrap-around sensor for monitoring changes in lung permittivity

Summary form only given. Non-invasive diagnosis methods are of great practical importance. We propose an on-body, non-invasive and wearable health monitoring sensor that forms a convenient wrap-around belt to be part of the clothing or worn under the clothing. This sensor serves to identify tissue abnormalities by measuring their permittivity. A schematic of the proposed sensor is shown in the figure below. The sensor is composed of a plurality of electrodes populated around the band, and is wrapped around the human torso. Ports (in between the electrodes) are excited sequentially with an RF signal at 40 MHz, and scattering parameters are collected from the neighboring passive ports (unused ports are terminated with 50 Ω). We note that receiving ports far away from the active (transmitting) one allow for deeper penetration. Thus, we in principle associate each probe with a certain penetration depth. Post processing is applied to extract the permittivity of deep tissues as a weighted sum of the measured scattering parameters. The uniqueness of this approach is that it suppresses interference from the outer body layers (skin, fat, muscle, and bone). The proposed sensor has been evaluated on a phantom making use of tissue-emulating gels to represent the human torso. Measurements showed that the error in calculating the permittivity of deep tissues remains below 11%. For medical applications, the sensor can be used to monitor the permittivity of lungs or other organs. In the case of lungs, the sensor serves as a precursor to congestive heart failure. At the conference, we will provide experimental results on the evaluation of the sensor. We will show its feasibility for imaging the electrical properties of the body.

Determining the relative permittivity of deep embedded biological tissues

This letter introduces a novel in vivo method for determining the dielectric properties of deep human tissues, including lungs. A surgery-free method is proposed for an on-body monitoring system to evaluate the electrical properties of internal body organs and to detect irregularities in real time. The method uses a set of electrodes (16 or 40 MHz in operational frequency) to obtain data that relates the electrical properties of the underlying biological tissue(s) to the measured port scattering parameters. By using multiple electrodes, effects from outer layers (skin, fat, and muscle) can be suppressed, allowing for an accurate characterization of deeper layers. Specifically, the dielectric constant is expressed as a weighted sum of the scattering parameters from each probe. The weights of the scattering coefficients are then determined through a training process to ensure that various changes in the outer layers do not contaminate the extraction of the dielectric constant(s) associated with deeper tissues.

A non-invasive lung monitoring sensor with integrated body-area network

This paper discusses the design and testing of a new robust system for in-situ continuous monitoring of the lungs condition. The system is composed of a body worn medical sensor with an accompanying wireless body area network (BAN) for remote health monitoring. The lung sensor consists of 17 electrodes, and operates at 40MHz. It aims to approximate the dielectric constant of the underlying lung tissue independent of variations in the outer layers (skin, fat, muscle and bone). Concurrently, the wireless BAN is used to transmit the measured dielectric constant to a mobile device via Bluetooth for continuous remote healthcare monitoring. In this paper, we present the design and experimental validation of the proposed lung sensor integrated with wireless BAN data link.