On body performance evaluation of passive RFID antennas inside bandage

Radio Frequency Identification (RFID) permits us to remotely exchange information utilizing electromagnetic waves in order to distinguish and track RFID tags by RFID readers. Usually RFID tags contain some code, which is employed for identification purpose. Utilization of RFID's for the detection of objects is becoming more common every day. On the other hand, the field of examining environmental parameters utilizing RFID antennas apparatuses is also evolving number of the environmental parameters are analyzed nowadays utilizing RFID tags, beginning with the identification of a modification of the electric field inside chamber due to change in pressure, to the analysis of change in the body temperature. In this thesis, development and measurement of RFID tags for the measurement of humidity inside bandage are performed. The basic idea of this measurement is to help the doctors in determining the condition of injury inside bandage, as most visible sign for the doctors to determine the condition of injury is humidness inside the bandage. Usually doctors open bandage to check whether the injury is in good condition or not. Detecting humidity level inside the bandage using RFIDs can help doctors to know status of injury without opening bandage, as opening bandage costs time and effort, also opening in unhealthy conditions can cause infection to the injury. Three different kinds of passive RFID tags are used to analyze the performance inside the bandage. One commercial RFID tag known as Dogbone designed by Smartrac is used. This antenna is to measure the humidity level in the industrial environments including construction material, health care, and automotive production units. Dogbone is a UHF RFID antenna, which employs RF Micron IC, innovative product that automatically adjust the input impedance in order to accumulate the changes in the external environment and present results in the digitized output. Although Smartrac´s Dogbone antenna is specially designed for humidity measurement, but because of its high sensitive antenna and weak insulation from the body, its performance dwindles greatly because of body and the bandage. Later on utilizing the brush painting fabrication method for antennas, two type of RFID tags are developed on paper and bandage. Paper utilized for silver brush painting is common A4 paper available for printing purposes while the bandage is made up of Rayon, which is stretchable and commonly used in the first aid kits. Developed antennas are sintered for 15 minutes and 125-degree centigrade, after which their performance is analyzed. Best RFID tags, among all fabricated RFID tags are chosen to do the measurement. Effects of body, bandage and humidity on the performance of RFID tag on paper and bandage RFID tags are analyzed. Smartrac ”Dogbone” and self-designed RFID tags on paper and bandage lose their performance by coming closer to the body, tags loose more performance when they are closer to the inner side of the arm and they are almost least affected by the outer side of arm. Increase in humidity also reduces performance of RFID tags, but interesting phenomenon observed is the effect by the number of turns of the bandage around the RFID tag on the body. The performance of RFID tag fabricated on paper and provided by Smartrac dwindles by increasing turns of the bandage but it’s interesting to note that the tag developed on bandage is almost unaffected by a number of turns of the bandage. Effect of bandage on the RFID tag fabricated on bandage is quite unique, this phenomenon can be utilized in different fields as measurement results show that RFID tag created using same material provide almost same kind of performance under pack-aging of same material but this need further studies to get affirmation