Circuitos de retificação para sistemas de recuperação de energia eletromagnética.

Abstract

Harvesting is inserted in the context of increasing the autonomy of circuits and lowpower systems. Specifically in the case of harvesting energy from electromagnetic waves, the usage of rectennas is highlighted, which are composed of antenna and rectifier circuits. This work was developed to design rectifier circuits for rectennas. Thus, to find the bandwidth containing the highest amount of power available in the environment, measurements of electromagnetic power level were made at UFCG´s installations. It was found that the Schottky diode is the most suitable rectifier device for rectenna operating in GHz bandwidth. It was performed the small signal analysis of Schottky´s diode. It was found that the junction voltage is the parameter that has the greatest influence on the diode, it efficiency and therefore should be carefully considered for the choice of the most suitable Schottky diode for rectifier circuits. Moreover, it was simulated and manufactured three rectifier circuits operating at high frequencies (GHz) and low power (-10 dBm or 0.1 mW). It was observed that the rectifier circuit which presents higher efficiency is a voltage doubler. It was observed that the rectifier circuit which presents higher efficiency is a voltage doubler. In addition, experiments of the rectifier circuit were performed, along with bioinspired antennas in order to obtain experimental results of a rectenna.