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.
Mobile Platform for Networked RFID Applications
RFID (radio-frequency identification) technology is widely used for supply chain management and inventory control. Furthermore, RFID has been recognized as a tool to realize a ubiquitous environment. The typical architecture of RFID applications comprises RFID tags, which are embedded in or attached to an object, an RFID reader, and IS (information services) server. The RFID reader reads the code in the RFID tag and interprets it by communicating with the IS server via a proper communication network. This is the typical architecture defined by EPCglobal. The RFID reader can be stationary or mobile. A mobile RFID reader affords more applications than the stationary one. In this paper, we describe the core components for realizing a mobile RFID application, such as a mobile RFID reader, platform architecture, and the corresponding network architecture. Although there are several types of mobile RFID readers in the market, we propose a specially designed mobile RFID technology that has several positive features including security, network architecture, operation scenario, and code resolution mechanism. Furthermore, we analyze the characteristics of the proposed technologies.
The unfolded universe of elementary particles. A geometric explanation of the standard model structure
We propose a geometric explanation of the standard model of Glashow, Weinberg and Salam for the known elementary particles. Our model is a generic Quantum Field Theory in dimension four, obtained by developing along a Lorentz sub-manifold the lagrangian of Einstein and Dirac in dimension twelve. The main mechanism which gives birth to the standard model is a certain gauge fixing of triality, which permits to identify the multiplicity of fermions, as seen from the four dimensional world, with the eight unseen dimensions of the generating universe. In this way we get the known tables of particles, explaining the series of fermions and the gauge bosons. We suggest that the Higgs field dynamics could appear through a bosonization of the right handed neutrino and correspond to a displacement in the unseen dimensions. We also propose hypotheses for dark matter, and perhaps dark energy. Then we suggest predictions to go beyond the standard model.