Flexible RFID tag with circular CSRR for body-area applications

The RFID technology has been widely used in wireless body-area applications lately because of its capability of sensing and signal processing in addition to the low cost feature. Even so, the RFID tag's performance in terms of resonant frequency, gain and reading range, for example, is usually degraded when close to the human body tissues, being important to ensure a way of compensating this problem. This paper presents the design of a flexible RFID tag operating in the American UHF frequency of 915 MHz with two pairs of metamaterial circular CSRR (Complementary Split Ring Resonators) applied to its ground plane which promoted an increase of the tag reading range in about 37%.