| Based on the requirements of the batteryless power system used in micro-power wireless sensor network note, a dual-band radio frequency rectifier is proposed in the paper. The rectifier can harvest the low density radio frequency energy in the environment, and rectify it into a DC voltage across a capacity. The rectifier can harvest the widespread 915 MHz and 2.4GHz radio frequency energy in the environment. And two different rectifier structure for different frequency bands are designed based on the actual energy density of the RF signal.Since the RF energy density is very low, the power conversion efficiency and the boost factor of the rectifier directly determine whether the post-stage circuit is working properly and its working range, the paper also from all aspects of the performance of the rectifier is improved. Therefore, the modified design in different aspect for the performance of the rectifier was carried out.In addition, this paper makes a detailed discussion and research for the antenna of the RF rectifier in consideration of the matching problem between the radio frequency rectifier and the antenna. Since the antenna matching network of the rectifier can not only maximize the transition rate of the energy received to the rectifier but also achieve a certain boost effect, it will improve the conversion efficiency of the rectifier. The design of the matching network needs to consider the input impedance of the rectifier itself, thus determining the voltage-boost magnification of the matching network and affecting the conversion efficiency of the rectifier. So the combination and optimization of the rectifier and the matching network is more practical.This circuit using TSMC65 nm process, is simulated with Cadence Spectre software. It can be obtained that, for the input energy density of the 915 MHz RF energy is-22.4d Bm, with the load ofloadR =4MW, the power conversion efficiency(PCE) of the rectifier is up to 12.1%, and the output voltage reaches 1.67 V. For the input energy density is-23.15 d Bm, with the same load, the output voltage can also reache 1.67 V. It meets the working conditions of the post-stage DC/DC circuit. For the 2.4GHz radio frequency energy, the maximum power conversion efficiency of the circuit at-15.19 d Bm input energy density is up to 31.7%. In the condition of-21.37 d Bm inputenergy density with the load ofloadR =5MW, the power conversion efficiency of the rectifier is up to 3.33%, and the output voltage can be raised to 1.1V, meet the processing requirements of the post-stage circuit. |
PDF Full Text Request