Antenna Design Method for RFID UHF tags

In this paper, we describe a simple method to design RFID UHF antennas, the main criteria being the chip/antenna matching in order to increase the detection distance of the tag. The study concentrates on simple printed radiating elements: inverted L-antennas (ILAs) and inverted F-antennas (IFAs). Especially by varying their geometric dimensions, the influence of their shapes is investigated in order to control their input impedance. It is demonstrated that various input impedances can easily be obtained. Thus, these antennas can match with different existing chips, mostly capacitive, by choosing carefully the shape of the antenna.