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Hu S.,Guizhou Normal University | Hu S.,Center for and Engineering | Si B.,China Institute of Technology | Shu H.,Guizhou Normal University | Shu H.,Center for and Engineering
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2013

Acting as sensors, passive radio frequency identification devices (RFID) tags can avoid sensor nodes bulky and realize battery-powered. So, ultra high frequency (UHF) passive RFID tags embedded in tires have a deep impact on tire life cycle management and tire monitoring, and have been used widely in the USA and the European Union. However, the transmission range is one of the hardest challenges in UHF passive RFID embedded in tires, because the rubber makes it harder to read the tag. The main difference between the common RFID and RFID embedded in tires is the communication medium, which attenuates RF power from the reader in RFID embedded in tires. To improve the transmission range and reliability of RFID embedded in tires, it is of great concern to study power transmission of wave propagation for UHF passive embedded RFID in tires, because the tags do not contain any battery and rely on the electromagnetic field for both power and communication. In this work, we studied the power transmissions for UHF passive embedded RFID in tires. In UHF passive embedded RFID systems in tires, the bidirectional radio link between reader and tags goes through air and tires. The total path loss is caused by several factors: reflection loss due to reflected power at tire-air boundaries, attenuation loss in the tires, and spreading loss which is simply due to the radiation properties of antenna. Each of these factors can be analyzed using the permittivity of tires and tire-air boundary conditions. So, the power transmissions are based on the permittivity of tires and tire-air boundary conditions. We use the OCP (open-ended coaxial probe) method to measure the permittivity of tires. By analyzing the radio link for UHF passive RFID, we establish a model of power transmissions of UHF embedded RFID in tires and make numerical analyses. Numerical analyses show that the error of the OCP methods for measuring the permittivity of tires is small, and the absolute error between the measured reflection coefficients and the simulated reflection coefficients is less than 0.04. It is suggested that the parallel polarization and normal incidence of wave should be chosen for improving the performance of the UHF embedded RFID in tires, and the depth embedded in tires should be chosen reasonably to avoid power transmission function locating valley also. In addition, it is necessary to optimize and design the antenna of tag for the impedance matching of tag antenna and chip. The research can provide a reference for the design of UHF passive RFID tags embedded in tires and TPMS (tire pressure monitoring system). Source

Song X.-W.,Guizhou Normal University | Song X.-W.,Center for and Engineering | Shi Y.-F.,Guizhou Normal University | Shi Y.-F.,Center for and Engineering | And 3 more authors.
Proceedings of 3rd Asia-Pacific Conference on Antennas and Propagation, APCAP 2014 | Year: 2014

The paper proposes two kinds of filter structures based on LTCC technology, which includes single layer stepped-impedance microstrip line structure and multilayer structure. According to the design of requirements, two kinds of filter with different structure are designed finally. And the difference between these two kinds of structures is proposed from physical dimensions and performance respectively. Filter in this paper is needed that the cut-off frequency is 1.7 GHz, the attenuation is larger than 30dB at 3GHz and less than 2dB in the pass band. The simulation results show that the two kinds of structures of LTCC filter can meet the desired demand. The single layer stepped-impedance microstrip line LPF has no advantage on physical size and the attenuation rate is lower than the multilayer LPF after 1.7 GHz. So the multilayer structure is dominant in the design of LPF. © 2014 IEEE. Source

Hu S.,Guizhou Normal University | Hu S.,Center for and Engineering | Shu H.,Guizhou Normal University | Shu H.,Center for and Engineering | And 2 more authors.
International Journal of Distributed Sensor Networks | Year: 2013

It is very important to detect a collapse hole for coal mine workers. The possibility of detecting the collapse hole using WSN is presented because the tunnel in coal mine is narrow and has poor working condition. Comparing three types of the hole detection methods, it is seen that the connectivity-based methods are used to detect coal mine collapse better than other methods. By establishing a 2D model of the collapse hole in coal mine, a class of algorithms for detecting the collapse hole in coal mine is described. Based on log-normal shadowing channel model, the accuracy of detecting the collapse hole in coal mine using Fisher information is analyzed. Numerical calculation shows that connectivity-based localization schemes are better to detect collapse hole of coal mine. © 2013 Shengbo Hu et al. Source

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