Microstrip Sensors for Biomedical Engineering

Currently, microstrip antennas and circuits acting as microwave sensors are used extensively in medical applications and systems that help people monitor their health constantly and easily in the comfort of their homes. This has resulted from the ongoing revolution in the process of wireless communications and the transfer of information. The patient can now be observed from home by the attending physician, wherever his/her home may be. Several medical applications using microwave sensors have been reported. These include the use of microstrip antenna and components to monitor human biofluids and tumors, specifically the breast in women. Microwave sensing is based on detecting differences in the electromagnetic properties––such as permittivity, reflection coefficient magnitude, and phase––of healthy tissues from those affected by tumors. Other applications for microstrip structures involve monitoring vital biofluids; for example, monitoring the glucose level in the blood for diabetics and NaCl level in sweat for hydration. Also, an important application for microstrip antennas involves antennas implanted in the human body for pacemakers and to make binoculars see inside the human body. While microwave sensing is harnessed in several medical applications, in this chapter the focus is on non-invasive breast, glucose, and sweat monitoring.