Design of RFID Tag Antenna Based on the Cole-Cole Model of Human Abdomen

In this work, electromagnetic human abdominal model is proposed with four layers including skin, fat, muscle, and small intestine. For each layer, fourth-order Cole-Cole model is chosen to calculate the permittivity. Combining with the electromagnetic propagation in multilayer media, we present reflection coefficients and phase information of incident wave among UHF band with different thickness of each layer. Then we give priority of consideration of each layer for RFID antenna design. According to RFID principle, we present the gain loss of RFID antennas attached to human abdomen, which shows that general gain loss of RFID antennas is 7 dB–13 dB compared with the antenna used in air.