Research On Composite Materials And Antenna Applied In UHF Band

In recent years,with the rapid development of electronic information technology,all kinds of electronic devices are gradually developing in the direction of intelligence,miniaturization and multi-function.In such a development trend,flexible electronic devices with its huge advantages in the field of wearable mobile electronics has aroused extensive interest of researchers at home and abroad,Among them,the realization of miniaturization of flexible antenna is the goal of this paper.The substrate of flexible antenna usually adopts organic flexible film material,but the low dielectric constant of the material will make the size of the antenna too large.The performance of the antenna can be improved by filling high-performance inorganic materials,so as to realize the miniaturization of the antenna.If we only improve the dielectric properties of the material,the antenna performance will be reduced under the same conditions.Therefore,this paper uses Co2Z ferrite with excellent magnetic properties as inorganic filler.Using ferrite particles as fillers can not only improve the dielectric constant of the material,but also improve the permeability of the material,which can effectively avoid the negative effects of high dielectric constant,and realize the miniaturization of the antenna.Firstly,a kind of ferrite material with low loss and high permeability was prepared by taking Co2Z ferrite as the research object.In this paper,Zn2+was selected to replace Co2+to improve the permeability of the material,the results show that when the substitution amount x was 0.4,the sample has high permeability,cut-off frequency and low magnetic loss.Therefore,the material with this substitution amount was selected as the main formula.On the basis of the main formula,WO3,Nb2Os and MoO3 were used for secondary grinding doping to further reduce the loss.The results show that Nb2Os doping can not improve the properties of the material,but WO3 and MoO3 doping can effectively reduce the loss of the material,and the ferrite sample with MoO3 content of 0.15wt%has the best performance.When the frequency was 200MHz,the permeability?r=19.3,the magnetic loss tan??=0.08,the dielectric constant ?r=48 and the dielectric loss tan??=0.041.Then,the best formulation of Co2Z ferrite was selected to prepare ferrite particles with uniform size,which were compounded with paraffin and PDMS to prepare different composites.The results show that the permeability,dielectric constant and loss of the composites increase with the increase of ferrite content,it was found that the Co2Z/PDMS composite flexible film is more suitable for the miniaturization of flexible antenna.The results show that the magnetic and dielectric properties of Co2Z/PDMS composite flexible films were as follows:permeability ?r=3.08,magnetic loss tan??=0.53,dielectric constant ?r=5.8,dielectric loss tan??=0.0062 when the ferrite particle filling amount was m=12g and the test frequency was 1 GHz.Finally,Co2Z/PDMS composite flexible film and PDMS flexible film were applied to 1GHz microstrip patch antenna as antenna substrate materials,and HFSS software was used for simulation analysis.The antenna simulation results show that compared with PDMS flexible film,the antenna can be greatly reduced in size by using Co2Z/PDMS composite flexible film as antenna substrate,while the antenna gain was only slightly decreased.The results show that the composite of Co2Z ferrite and organic compound can effectively realize the miniaturization of flexible antenna.