Wireless RF communication in biomedical applications

Abstract

This paper focuses on wireless transcutaneous RF communication in biomedicalapplications. It discusses current technology, restrictions and applications and alsoillustrates possible future developments. It focuses on the application in biotelemetry wherethe system consists of a transmitter and a receiver with a transmission link in between. Thetransmitted information can either be a biopotential or a nonelectric value like arterialpressure, respiration, body temperature or pH value. In this paper the use ofradio-frequency (RF) communication and identification for those applicationsis described. Basically, radio-frequency identification or RFID is a technologythat is analogous to the working principle of magnetic barcode systems. Unlikemagnetic barcodes, passive RFID can be used in extreme climatic conditions—alsothe tags do not need to be within close proximity of the reader. Our proposedsolution is to exploit an exciting new development in making circuits on polymerswithout the need for battery power. This solution exploits the principle of a surfaceacoustic wave (SAW) device on a polymer substrate. The SAW device is a set ofinterdigitated conducting fingers on the polymer substrate. If an appropriate RFsignal is sent to the device, the fingers act as microantennas that pick up thesignal, and this energy is then converted into acoustic waves that travel across thesurface of the polymer substrate. Being a flexible polymer, the acoustic waves causestresses that can either contract or stretch the material. In our case we mainlyfocus on an RF controllable microvalve that could ultimately be used for fertilitycontrol.