RF-powered UHF-RFID analog sensors platform

An RF powered UHF-RFID passive sensors platform was realized using discrete components and printed antennas designed to resonate at 868 MHz, used both for energy harvesting and data transmission. The tests demonstrate the possibility for the system to operate autonomously within the reading range of a standard RFID reader, that acts both as the RF power source and the receiver of the data stored in the tag user memory. The microcontroller can be interfaced on the same substrate with a sensor made of polymeric materials, sensible to physical parameters or chemical agents. RF-powered UHF-RFID analog sensors platform (PDF Download Available). Available from: http://www.researchgate.net/publication/279193365_RF-powered_UHF-RFID_analog_sensors_platform [accessed Sep 14, 2015]

A Microchip Integrated Sensor for the Monitoring of High Concentration Photo-voltaic Solar Modules

Abstract A CMOS sensor fabricated in 0.35μm technology, specifically designed for the monitoring of High Concentration Photo-Voltaic (HCPV) modules, is presented. The microchip was designed to monitor temperature and illumination of each solar cell in a module. Temperature is measured by monitoring the base-emitter voltage of two coupled, diode connected, bipolar transistors, while the illumination sensor is an integrated p-n junction photodiode. A custom communication protocol is implemented in the chip to allow the sharing of a two-wire communication resource among the cells

Temperature Effects on the Efficiency of Dickson Charge Pumps for Radio Frequency Energy Harvesting

An experimental study is carried out to assess the effect of temperature on the conversion efficiency of ultrahigh-frequency energy harvesters based on diode-capacitor Dickson charge pumps, frequently used in self-energizing circuits, such as in radio frequency identification tags or in wireless sensor nodes. Using off-the-shelf Schottky diodes often adopted for this application, it is shown that the harvester conversion efficiency at 868 MHz is temperature dependent due to the changing rectification ratio, namely the ratio between the forward and the reverse current flowing through the low barrier height Schottky diodes, which both show a positive derivative with T. The experimental study, supported by SPICE simulations, has shown that a temperature variation might be particularly harmful at the lowest incident power regimes, when even a minimal drop in the conversion efficiency might determine the out-of-servicing of a wirelessly energized circuit

temperature sensing characteristics and long term stability of power leds used for voltage vs junction temperature measurements and related procedure

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