2.4 G Electromagnetic Radiation Characteristics Of Target Identification Card

The target identification card of2.4G is a mobile device, which used the2.4G wireless technology whose frequency-band is from2.405GHz to2.485GHz to communicate with the base station. Its radiator is thequarter-wavelength monopole antenna, printed on the PCB board, made up withcopper. With the advances in technology and the widespread of the2.4Gwireless technology, more and more antennas integrated on the PCB board areused, and the size is required smaller. So, the research the antenna’s radiatingcharacteristic is seemingly very important. And also, for the wirelesscommunication between the physical objects in the Internet of Things which isdeveloping in the nearly years, the research has great significance.The main content of text is:1. Based on the Maxwell’s equations, text derived the radiation field and theradiation characteristic parameters of the ideal current element first. Andthen solving integral along the axis of the half-wavelength dipole, whichcould be seen as many of current elements, obtained the radiation field andthe radiation characteristic parameters of the half-wavelength dipole. Andthen using the electromagnetic simulation software named High FrequencyStructure Simulation, simulate the half-wavelength dipole in free space.Then compared the simulation results of the half-wavelength dipole with theresults of the former theoretical analysis, verify the accuracy of thesimulation.2. For the radiating antenna of the card, used the HFSS to establish the antennamodel, simulated and analyzed, and then obtained the antenna’s far fieldradiation characteristic parameters and the near field radiation pattern.3. Using the GSP-830Spectrum Analyzer, which can detect theelectromagnetic waves at the frequency of0to3GHz, tested the signalradiated by the target identification card, got the values of near-fieldradiation intensity at different singles, analyzed and processed the data, drawthe graphics, and compared with the simulating results, and could see the two had a certain degree of similarly.4. Analyzed the influence, the values of the length and the height of theantenna had on the antenna radiation characteristic, gained the far fieldradiation pattern while the values of the length or the height were different,and the curves of the peak-directivity, peak-realized-gain, and so on, whilethe values of the length or the height were changing.5. At last, for the structural parameters of the antenna of the card, did theoptimization; got the antenna structure with the minimum reflectioncoefficient, and at this time, the power the antenna accepted was themaximum. Gained the radiating characteristic of the optimized antenna, andcompared with the radiation performance of antenna before optimizing,could see the radiation efficiency improved.