Adrian-Ioan Petrariu

ANALYSIS AND DESIGN OF A LONG RANGE PTFE SUBSTRATE UHF RFID TAG FOR CARGO CONTAINER IDENTIFICATION

Abstract In this paper, a high-performances microstrip antenna for UHF (ultra high frequency) RFID (radio frequency identification) tag is designed, prototyped and tested. The antenna consists of two main components: a 1.52 mm RT/duroid 5880 laminate substrate on which the antenna is designed and a 10 mm polytetrafluoroethylene (PTFE) dielectric material placed as a separator between the antenna and the reference ground plane for the microstrip antenna. With this structure, the RFID tag can reach a maximum reading distance of 19 m, although the antenna has a compact size of 80 mm × 50 mm. The long reading distance is obtained by attaching to the antenna an RFID chip that can provide a reading sensitivity of −20.5 dBm. The high bandwidth from 677 MHz to 947 MHz measured at −10 dB, makes the tag being usable worldwide especially for cargo container identification, the main purpose of this research.

Power Transfer Optimization for HF RFID Systems Working in Metallic Environments

Abstract In wireless systems, the power transfer efficiency is very important. Many systems are used in harsh environments and the signal transmitted can be drastically affected by these environments. HF RFID systems are widespread nowadays, in many domains, but the metallic environments are an impediment to the extension of these systems in different applications. In this paper is presented a solution in optimizing the power transferred through the RFID reader antenna in the identification area where tags are found. This solution involves using an automatic matching unit (AMU) circuit that can match the impedance of the reader antenna at 50 Ω, even if the metallic environments located nearby are constantly changing. Using the proposed solution and only 1cm between the reader antenna and a metallic plane the reading distance is increased up to 75% from the reference distance (reading distance when no perturbing environment is used around). The fast tuning process can identify the tags even if they are attached by moving objects.

Metal mountable microstrip patch UHF RFID tag antenna

This paper relates the development of a simple metal mountable RFID tag designed for ETSI band. One important aspect given by this design is using a simplistic structure that can be adjusted for different type of IC chip impedances that exists on the market. The antenna is simulated and measured and the obtained results reveals that the tag can be compared with other prototypes, achieving good performance when is attached to a metallic surface. Using an 8dBi antenna gain for the reader and an output power of 30dBm, is obtained a maximum reading distance of 4.8m when is attached to a metallic surface and 3.1m in free space.

An analytical determination of the reading volume for an HF RFID antenna

An important aspect that directly affects the RFID system performances is represented by the reading distance of the RFID tags. Regarding this issue, in order to identify areas where the system provides high efficiency, we must determine the maximum reading volume of the RFID reader antenna. This paper approaches a series of mathematical models in order to evaluate the reading volume for different types of HF RFID antennas. By using these models we can calculate the intensity of the magnetic field generated by a circular or a rectangular loop antenna, in any point around the antenna. The results obtained during the tests are verified using MATLAB toolbox simulation.