Reduction of Proximity Effects on UHF Passive RFID Systems by Using Tags With Polarization Diversity
A new technique that enables passive ultra high frequency (UHF) radio frequency identification (RFID) tags to be read when they are placed in close proximity in an array is presented. This paper demonstrates that, in a linear tag array with a tag separation of 1 cm, the interaction between the backscattered waves and incident wave causes a significant degradation in tag sensitivity. It is found that the use of tags that have polarization diversity can improve the read performance when they are placed in close proximity to one another compared with conventional linear tags. Two ways of achieving polarization diversity are studied in this paper, namely: 1) using a circularly polarized tag and 2) using a cross-polarized tag pair. Both methods show an improvement in close proximity read performance and it is experimentally demonstrated that by using cross-polarized tag pairs in an array, one achieves on average a 2.6-dB increase in read power margin for a 57-tag array with 1 cm separation compared with using conventional linearly polarized tags.
Design and simulation of NFC printed antenna in near field wireless communication for SDC
Near Field Communication (NFC) is emerged in the last decade. NFC is a short range high frequency and low bandwidth wireless communication technology. Passive Radio Frequency identification (RFID) tags are usually used with a system where one end of communication is isolated and powerless in nature. There are several applications of RFID-NFC systems despite of its drawback such as communication can happen between only two devices at a time and, its short range (0-20 cm). In this paper, the simulation results of a novel antenna at 13.56 MHz are presented. NFC works on both active and passive devices using various modes of operation. Its short-range property is utilized here for authentication of degree certificate awarded by universities. The antenna is flexible, robust and light weight so that it can be easily sandwiched inside the paper. In this paper a NFC antenna is designed which is ideal for manufacturing and assembling into the thin layers of degree certificate paper issued by examining authority. Calculations are done to select antenna dimensions before the final process. An antenna design is achieved using simulations and parameter optimization with simple method without making it complicated.
A Tourist Supervise System Based on RFID
A tourism team is usually built up by tourists from different areas with different backgrounds and lifestyles, so that how to manage a tourism team has become a hot topic of current research. In order to solute this problem, we have designed a management system based on radio frequency identification technology which composes by tag reader and tans. The tag reader is carried by guider and the tags are carried by tourists, so guider can monitor every tourist who carried tag. Each tag has its own special identification number, and each number corresponds to one person. Guides can call every one who carries the tag at any time, so this system could solute the management problem to some extent.