Ilie Finis

The design of a street lighting monitoring and control system

Increasing the efficiency and automation of lighting control systems is an important issue that has been addressed by many research centers. This paper presents the design and implementation of a lighting monitoring and control system that can be employed for street lighting control. The main advantages of this system consist in substantially reducing the costs related to energy consumption and maintenance, by dimming the light intensity using vehicle detection. The system architecture is based on a WSN (Wireless Sensor Network) communication protocol.

Performance evaluation of Power Line Communications over power transformers

Power Line Communications (PLC) are used in Automatic Meter Reading (AMR) systems more and more this day. This paper analyses the problems encountered when the PLC signal is needed to be sent through the body of a power transformer, we have made field tests to verify if communication can take place and with what performances. For this a comparative analyze of protocols PRIME and G3-PLC data transfer has been made, when communication took place as follow: through the secondary winding of a MV/LV power transformer from a phase to another, through two power transformers from one secondary LV winding to the other one secondary LV winding over the MV power line that feeds the both of them, and through the second power transformer when distance on one phase was increased to 50 m. Parameters as BER (Bit Error Rate), PER (Packet Error Rate), data rate the signal spectrum are analyzed.

A mathematical approach of a HF RFID multi loop antenna for metallic environments

The most important factors that may influence and affect the performance of HF RFID systems that use passive tags, consists in the effects of the metallic environments in the proximity of the antenna. In order to overcome a part of these issues, both the device antennas and their impedance matching units must be optimized. This paper presents a mathematical model that enables the identification of the optimal size of a multi loop HF RFID antenna that would encompass the coordinates of a given surface. The antenna has been mathematically modeled, simulated and tested for a specific situation when the metal plate is positioned in its close proximity.

Performance evaluation of 13.56 MHz RFID antenna operating in metallic environments

The present paper analyses and measures the effects that the presence of a metallic surface can induce on the integrated antennae of HF RFID systems operating on a 13.56 MHz frequency. The results of the conducted measurements have been compared with those arrived at by means of the Ansoft HFSS application. Thus, the conducted tests and simulations reveal the fact that the resonant frequency increases in direct ratio to the distance between the loop antenna and a parallel metallic surface. When the antenna is positioned within less than 3 cm from a metal surface, its performance is drastically reduced and the resonant frequency increases from 13.56 MHz to 14.75 MHz, which eventually compromises the entire communication process, since the interrogation zone is considerably reduced. Further analyses are conducted on the influences exerted on the performance of the antenna, which is made from various materials, such as copper or aluminium. Apart from the detailed account of these issues, we also suggest a series of solutions that will eventually enable the expansion of the interrogation zone.

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.