Novel Wearable Antennas for Communication and Medical Systems

Albert Sabban

• Publisher: CRC Press
• Year: 2017
• ISBN:
  9781351623124
• Edition: 1
• Topic: Tecnologia e ingegneria
• Subtopic: Microelettronica

Wearable antennas are meant to be incorporated as part of clothing or placed close to the body. Wearable antennas can be used in countless communication applications including tracking and navigation, medical applications, imaging and detection, RFID, mobile computing and public safety. The book "Novel Wearable Antennas for Communication and Medical Systems" discusses the challenges and technology to develop compact, efficient, wearable antennas. The book begins by presenting elementary communication, electromagnetics and antenna topics needed for engineers and students that do not have a background in design, principles, and features of antennas, printed antennas, wearable antennas, and compact antennas for communication and medical applications. Throughout the book each chapter also covers sufficient mathematical details, physical details and explanations to enable the reader to follow and understand the topics presented. New topics and design methods in the area of wearable antennas, metamaterial antennas, active printed antennas and fractal antennas for communication and medical systems are presented and discussed throughout the book. The book presents computed and measured results in the vicinity of the human body. The book also covers topics such as RF measurement techniques, measurement setups and design considerations. The antennas developed and analyzed in this book were designed and optimized by using 3D full-wave electromagnetics software.

1 Wearable Communication and Medical Systems

Wearable technology has several applications in personal wireless communication and medical devices as presented in [1–8]. The biomedical industry has been in continuous growth in the last few years. Several medical devices and systems have been developed to monitor patient health as presented in several books and papers [1–44]. Wearable technology provides a powerful new tool to medical and surgical rehabilitation services. Wearable body area networks (WBANs) can record electrocardiograms and measure body temperature, blood pressure, heartbeat rate, electro-dermal activity, and other healthcare parameters.

1.1 WEARABLE TECHNOLOGY

Accessories that can comfortably be worn on the body are called wearable devices. Wearable technology is a developing multidisciplinary field. Knowledge in bioengineering, electrical engineering, software engineering, and mechanical engineering is needed to design and develop wearable communication and medical system. Wearable medical systems and sensors are used to measure and monitor physiological parameters of the human body. Biomedical systems in the vicinity of human body may be wired or wireless. Many physiological parameters may be analyzed using wearable medical systems and sensors. Wearable medical systems and sensors can measure body temperature, heartbeat, blood pressure, sweat rate, and other physiological parameters of the person wearing the medical device. Wearable technology may provide scanning and sensing features that are not offered by mobile phones or laptop computers. It usually has communication capabilities and users may have access to information in real time. Several wireless technologies are used to handle data collection and processing by medical systems. The collected data may be stored or transmitted to a medical center to analyze the collected data. Wearable devices gather raw data that is fed to a database or to a software application for analysis. This analysis typically may result in a response that might alert a physician to contact a patient who is experiencing abnormal symptoms. However, a similar message may be sent to a person who achieves a fitness goal.

Examples of wearable devices include headbands, smart wristbands, belts, watches, glasses, contact lenses, e-textiles and smart fabrics, jewelry, bracelets, and hearing aid devices.

Usually wearable communication systems consist of a transmitting unit, a receiving unit, a data processing unit, and wearable antennas.

Wearable technology may influence the fields of transportation, health and medicine, fitness, aging, disabilities, education, finance, gaming, entertainment, and music. Wearable devices will be in the next decade an important part of individuals’ daily lives.

1.2 WEARABLE MEDICAL SYSTEMS

One of the main goals of wearable medical systems is to increase disease prevention. By using more wearable medical devices a person can handle and be aware of his private health. Sophisticated analysis of continuously measured medical data of a large number of medical centers’ patients may result in improved low-cost medical treatment.

1.2.1 APPLICATIONS OF WEARABLE MEDICAL SYSTEMS

Wearable medical devices may

• Help to monitor hospital activities
• Assist diabetes patients
• Assist asthma patients
• Help solve sleep disorders
• Help solve obesity problems
• Help solve cardiovascular diseases
• Assist epilepsy patients
• Help in treatment of Alzheimer’s disease patients
• Help gather data for clinical research trials and academic research studies

1.3 WEARABLE MEDICAL SYSTEMS

Several physiological parameters can be measured using wearable medical systems and sensors. Some of this physiological data is presented in this chapter.

1.3.1 MEASUREMENT OF HUMAN BODY TEMPERATURE

The temperature of a healthy person ranges between 35°C to 38°C. Temperatures below or above this range may indicate that the person is sick. Temperatures above 40°C may cause death. A person’s body temperature may be transmitted to a medical center and if needed the doctor may contact the patient for further assistance.

1.3.2 MEASUREMENT OF BLOOD PRESSURE

A blood pressure measurement indicates the arterial pressure of the blood circulating in the human body.

Some of the causes of changes in blood pressure may be stress and being overweight. The blood pressure of a healthy person is around 80 by 120, where the systole is 120 and the diastole is 80.

Changes of ten percent above or below these values are a matter of concern and should be examined. Usually blood pressure and heartbeat are measured in the same set of measurements. The blood pressure and heartbeat may be transmitted to a medical center and if needed the doctor may contact the patient for further assistance.

1.3.3 MEASUREMENT OF HEART RATE

Measurement of the heart rate is one of the most important tests when examining the health of a patient. A change in heart rate will change the blood pressure and the amount of blood delivered to all parts of the body. The heart rate of a healthy person in 72 beats per minute. Changes in heartbeat may cause several kinds of cardiovascular disease. Traditionally heart rate is measured using a stethoscope. However, this is a manual test and is not so accurate. To measure and analyze the heartbeat a wearable medical device may be connected to a patient’s chest. Medical devices that measure heartbeat can be wired or wireless.

1.3.4 MEASUREMENT OF RESPIRATION RATE

Measurement of respiration rate indicates if a person is breathing normally and if the patient is healthy. Elderly and overweight people have difficulty breathing normally. Wearable medical devices are used to measure a person’s respiration rate. A wired medical device used to measure respiration rate may cause uneasiness to the patient and cause an error in measurements of respiration rate. It is better to use a wireless medical device to measure respiration rate. The measured respiration rate may be transmitted to a medical center and if needed the doctor may contact the patient for further assistance.

1.3.5 MEASUREMENT OF SWEAT RATE

Glucose is the primary energy source of human beings. Glucose is supplied to the human body usually as a monosaccharide sugar that provides energy to the human body. When a person does extensive physical activity, glucose comes out of the skin as sweat. A wearable medical device can be used to monitor and measure the sweat rate of a person during extensive physical activity. A wearable medical device can be attached to the person’s clothes in proximity to the skin to monitor and measure the sweat rate. This device can also be used to measure the sweat Ph, which is important in diagnosis of diseases. Water vapor evaporated from the skin is absorbed in the medical device to determine the sweat Ph. If the amount of sweat coming out of the body is too high, the body may dehydrate. Dehydration causes tiredness and fatigue. Measurements of sweat rate and Ph may be used to monitor the physical activity of a person.

1.3.6 MEASUREMENT OF HUMAN GAIT

The movement of human limbs is called the human gait. Human gaits are the various ways in which a human can move. Different gait patterns are characterized by differences in limb movement patterns, overall velocity, forces, kinetic and potential energy cycles, and changes in contact with the ground. Walking, jogging, skipping, and sprinting are defined as natural human gaits. Gait analysis is a helpful and fundamental research tool to characterize human locomotion. Wearable devices may be attached to different parts of the body to measure and analyze human gait. The movement signal recorded by these devices can be used to analyze human gait. Temporal characteristics of gait are collected and estimated from wearable accelerometers and pressure sensors inside footwear.

In sports, gait analysis based on wearable sensors can be used for sports training and analysis and for the improvement of athletic performance. The ambulatory gait analysis results may determine whether or not a particular treatment is appropriate for a patient. Motion analysis of human limbs during gait is applied in preoperative planning for patients with cerebral palsy and can alter medical treatment decisions. Parkinson’s disease is characterized by motor difficulties such as gait difficulty, slowing of movement, and limb rigidity. Gait analysis has been ...