Ultra-Low Power Microwave Components and Systems for Remote Health Monitoring Applications

This talk examines ultra-low power microwave components and systems for remote health monitoring applications. In particular, backscatter radio frequency identification (RFID) technologies are investigated as one of the key enabling technologies sensor networks. Backscatter RFID in sensor networks relies on the radio communication between an RFID reader, acting as a control unit, and a multitude of passive or semi-passive RFID transponders (tags), acting as sensor nodes. All power for the transmission of the sensor data is drawn from the electromagnetic field radiated by the reader. Hence, their low-power consumption makes backscatter tags appropriate for remote health monitoring applications that require small, light-weight, and low-maintenance sensor nodes. In backscatter RFID, it is vital to ensure a reliable power transfer and wireless communication between the reader and the tags. Thus, the major design goal for microwave engineers is to realize microwave components and systems that lead to a high performance in terms of power transfer and communication. This talk presents among others two design examples of ultra-low power microwave components and systems, i.e., an on-body backscatter RFID system at 900 MHz and 2.45 GHz and a backscatter RFID sensor tag that monitors passively the varying curvature of the human body at 5.8 GHz. The on-body system performance is evaluated in a realistic indoor scenario through channel measurements, while the transducer prototype is optimized with respect to the sensor sensitivity to bend and with respect to the sensor tag modulation efficiency.