Design And Implementation Of 2.4GHz RF Energy Collector

In recent years,the wireless technology have developed rapidly.Ambient energy collection as a very important part in wireless power supply,a new energy utilization mode.This paper designs a 2.4GHz RF energy acquisition and power management system,including the design of front-end energy receiving antenna of RF energy acquisition system,the design of impedance matching rectifier boost circuit,and the load communication experiment is carried out by selecting the temperature sensor node module.The 2.4GHz microstrip antenna monomer and 2×2 are designed on the basis of FR4The two parallel feed antenna arrays,S₁₁ are-15d B and-38d B respectively,the single antenna’s bandwidth of the is 40M,the microstrip antenna array’s bandwith is pretty wide that covers all the bandwidth of 2.4G band,and the maximum radiation direction gain of the measured microstrip antenna array in the darkroom is 10.4d B.The overall test shows that the antenna performance is excellent.The impedance matching double voltage rectifier circuit achieves good impedance matching.The overall central frequency of the circuit is accurate and the size is small.The maximum current output of the whole energy collector is 350μA.The maximum open circuit voltage is above 1.5V,and the RF-DC conversion characteristics is very well.The power management chip of BQ25504 micro watt level and the appropriate peripheral circuit are used to form the boost module.The DC output voltage of RF energy acquisition system can be multiplied well,and then the energy can be stored by super capacitor or rechargeable lithium battery.The Bluetooth module HC-42 can communicate with the host computer and send the indoor temperature data collected.After testing,the RF energy acquisition and energy management system designed in this paper can effectively collect the signal energy from the transmitter and convert it into DC,and the DC energy can reach more than 3V after boosting.The DC energy can be stored and charged for super charge.The charging time of 30 m F super charge from initial100m V to 3.11V is about 12 minutes.The working time of the system communication is about 1.7s after using 40 m F super charge.Five temperature data are sent each time.After one discharge,the system will be charged to about 2.8V immediately.The time is about33s.Then the system will continue to charge for the next data transmission communication.The design and implementation of 2.4GHz RF energy collector is completed.