Circuito captador de energía de radiofrecuencia

Abstract

We can use radio frequency energy in order to fuel autonomous sensors. This energy can be which is radiated into the environment or directly from a source dedicated to it. For this we will use antennas which will receive low signal powers, in this case 0 and -10 dBm with 868MHz of frequency, that through an adaptation network, (formed by a capacitor and a coil), and a rectifier-filter signal (using diode HSMS2850 and a capacitor of 1nF) will make that power transference delivered to the sensor it will be the maximum possible. We decided that the antenna resistance (R_s) was 50Ω (a typical antenna value) because at the moment to measure real results we will use a signal generator with a 50Ω output. This project is based on impedances adaptation of LC network to obtain high efficiencies of the circuit. In simulation section with ADS-2006 program we obtained efficiencies around 70% where the circuit was fuel at 0dbm. Meanwhile the circuit was fuel at -10 dbm the efficiency didn't overcome the 60%. In this case the components were a 0.6pF capacitor and a 31.3nH coil. In implementation of PCB section with an input power of 0 dBm (with a 0.6pF capacitor and a 33nH coil) the circuit overcame the 50% and with -10dBm it overcame a performance upper than 40%, but all this with an unwanted frequency.