In recent years, radio frequency identification (RFID) microwave technology receives great attention because of its advantages, e.g. long identification distance, small size of antenna, high identification speed and strong anti-collision ability. RFID tag plays one of the most important roles in logistics, and therefore special attention should be paid to tag design. In this paper, we present a 2.45G semi-active tag design, which is compatible with ISO 18000-4. The proposed tag can switch the manners of working between active and passive. When the generated RF-power is sufficient to operate, the tag works as a passive tag, and low noise amplifier (LNA), oscillator (OSC) and power amplifier (PA) are cut off to save the whole chip power consumption mostly. Otherwise it operates in active mode using battery power, and the working distance is greatly increased as a result of using PA.

This paper presents a novel RFID antenna which makes solar cell and tag antenna combine as an integrated unit. The solar cell is used as a parasitic element in a tag antenna. The original feature of a solar cell (DC current generation) remains, and the solar cell which can supply the energy to activate the IC is now used as a parasitic patch at the same time. Besides a general description of solar cell antenna, the size and the simulated results of the antenna are also shown.

The growing interest of Radio Frequency Identification (RFID) applications has seen problems emerging in the identification of object, especially those that contain conductive material. A low-cost novel tag antenna for a RFID tag which could be mounted on the side of cigarette carton is proposed in this paper. Since the cigarette carton contains conductive material, radiation properties of the antenna could be affected significantly. The specific parameters of the antenna were optimized based on the Finite Element Method (FEM). The performance of the tag antenna design affixed to the cigarette carton containing metallic foil is verified with read range measurements. The proposed antenna has a simulated bandwidth from 863 MHz to 943 MHz ( < -10 dB) for conjugate-matching with a commercial tag chip.