Optimal Designed Implementation Of Fractal Dipole Antenna Based On Arc Of The Trigeminal Tree Structure

With the rapid development of RFID communication technology,and the accuracy of the tags and readers in the system is much higher than before.And the hardware integration of the chip is much higher with the manufacturing capacity continuous improvement.So it is much stringency that the antenna of the RFID system must meet the miniaturization requirement.Based on the understanding of fractal theory and analyzing the characteristics of fractal theory on antenna designing,the situation of some fractal antenna are introduced,such as the binary fractal reader antenna,the rectangular fractal label antenna and the arborescence antenna.And the triangular tree curved fractal structure antenna is designed on the basis of the binary tree curved fractal structure.The work done,innovation and implementation of the results are mainly including three sections:(1)The triangular arc antenna is designed by HFSS software,first setting the driven model.And adding the variables of designing,next step is modeling the antenna structure,setting the excitation,radiation boundary,2.45 GHz operating frequency,and sweep frequency.Then simulation of the antenna is carried out after setting these parameters,and the simulation results are analyzed to meet the requirements of the antenna characteristic parameters.In addition,the parameter of the balun structure,the oscillator structure and the impedance matching structure are optimized,and the triangular tree curved fractal with better performance is designed.(2)This antenna main modify the structure of the binary tree into a three-tree structure,and the triangular tree in each branch of the arc structure from 90 degrees to 180 degrees.These two structures combine with each other to relative increase the area of the patch antenna,and to enhance the radiation characteristics of the antenna to some extent.With this special structure,it is possible to increase the length of the antenna element in the same area,and to reduce the size of the antenna in a way.(3)The antenna designed in this paper is used the relative permittivity 4.4r?(28),dielectric loss tangent tan?(28)0.035 of the epoxy glass plate as a dielectric substrate.And the antenna is fed by simple microstrip balun,achieved better impedance matching by using a parallel two-wire structure.The simulation results of HFSS electromagnetic performance show that the resonant center frequency of the antenna is 2.45 GHz,the value of the S11 parameter at the center frequency is-36 d B,the impedance matching effect is ideal,the frequency range in the S11 less than-10 d B if from 2.28 GHz to 2.49 GHz,the bandwidth is 210 MHz,the relative bandwidth is 8.5%,the gainsize is 1.49 d Bi.This antenna is material processed and tested,the measured results of input reflection coefficient S11 and the pattern is very consistent with the software simulation results.The size of the antenna has been reduced to meet the requirements of miniaturization of the antenna.This antenna will have a broader application prospects in the future.