Research And Design Of An Active Electronic Tag And Antenna Applied On RFID System

With the quick development of Internet of things, radio frequency identification technology hasbeen paid more and more attention as one of the key technologies of the Internet of things. The mainwork of this paper is to produce an active tag working in the2.4GHz frequency point by means of RFchip nRF24L01. As well as completing the circuit design and tag measurements, external antennas thechip required are designed and produced in this article. The innovation and main research of thisthesis can be summarized as follows:Wireless communication function is built through the use of single-chip MSP430F149and RFchip nRF24L01. These two parts are the core hardware in the active tag circuit based on the RFIDsystem. In order to test the tag, serial interface circuit, microcontroller program download export andpower supply circuit are integrated into the same circuit board. The tag also reserved pins fordisplaying.Two RFID tag antennas are proposed and designed. One is the inverted F type antenna structure.The antenna has the advantages such as simple structure and small size, bandwidth152MHz(2.356~2.508GHz), covering the RF chip working frequency. According to the testing results, theantenna is very suitable for the actual circuit with good gain and radiation characteristic. The other isL-shaped microstrip printed-monopole antenna. Radiation patch appears L type with microstrip linefeed. This microstrip antenna works in the dual frequency, respectively, for2.45GHz and5.8GHz,with enough bandwidth. Finally, measurement results are agreed well with simulation results, whichproved the correctness and feasibility of the design of antenna. Additionally, these two antennas cansatisfy the performance requirements of the active tag and can be used in the RFID tag systems.Program debugging will be done when the tag circuit board is processed. The first step is to testthe communications between MCU and serial interface, the second is the SPI port communicationsbetween MCU and RF chip and the last is test between one and another tag. Serial debugging assistantsoftware play an important role during the program debugging. For the purpose of communicationdistance test, we make the tag work under the different transmit power. It is obtained thatcommunication distance maximum can reach68meters when received tag and transmitted tag bothwork under power of0dBm. Finally, the thesis summarizes the insufficient of tag research and proposes the next step for the future.