RFID Label is widely apply in Warehouse Management, Logistics, production line and medical equipment etc.
Radio Frequency Identification (RFID) is a non contact automatic identification and data acquisition technology that uses radio waves. With the excellent features, such as no line-of-sight requirement, long operating range, and working under harsh environment, RFID is widely used in various information systems. Ultrahigh frequency (UHF) RFID has many advantages compared to low-frequency system, such as longer read range and faster data rate and programmability. UHF RFID technology has become popular in everyday life. A typical RFID tag consists of an antenna and an integrated circuit chip. UHF RFID system involves electromagnetic interaction between the antenna of tag and reader. Back scattering modulation will have good performance when the microchip matches its internal load to the antenna. The tag’s antenna plays a key role in the system performance, such as read range, the power consumption of the microchip, and the overall size of the tag. Since most UHF RFID tags are attached onto size-constrained objects, it is necessary to design small-geometry antennas with good radiation efficiency. To reduce the size of antenna, there are two strategies: meandering and inverted-F structures.
Different resonance frequencies and impedance can be achieved by adjusting the number of the meanders, which can help to reduce the size of the antenna. Due to the radiation patches, the input impedance of the antenna can be flexibly tuned in a large scale. The proposed antenna is printed on polyethylene (PET) substrate with a total volume of 48 mm × 13.7 mm × 0.5 mm. Modeling and simulation results show that the reflection coefficient of the antenna is less than 15 dB at 860–960 MHz. Experimental studies demonstrate that the minimum threshold power of the antenna is between 23 and 26 dBm and the measured read range is 3-4 um.
