Study On The Application Of Artificial Electromagnetic Materials In Leaky Wave Antenna And Polarization Converters

Artificial electromagnetic materials provide a new possibility for antennas to realize electromagnetic regulation,which is conducive to the needs of antennas to achieve multi-functional composite,performance agility,stealth,and other electromagnetic wave regulation capabilities.Artificial electromagnetic material with two-dimensional structure can realize polarization deflection,absorption,focusing and other functions of electromagnetic wave,and have the characteristics of easy preparation,low loss and good compatibility,which have become the focused issues of many disciplines and have been widely used in practical life.Based on the singular electromagnetic properties of artificial electromagnetic materials,the polarization conversion artificial electromagnetic material and the composite left and right hand leaky wave antennas are studied in this study.The specific research contents are as follows:1.A composite left-and right-handed microstrip leaky wave antenna with high scanning rate was proposed.The antenna adopts a periodic structure with curved line leaky wave units and time delay lines placed alternately,the effect of size parameters of the curved line unit on the dispersion curve of the leaky wave unit was analyzed,and also the actual antenna is fabricated and measured.The measured results show that,the-10 d B impedance bandwidth of the proposed antenna is 9.7～11.45 GHz,in the frequency band of 9.7～11.1 GHz,the main radiation beam angle is-50°～+31° and the corresponding scanning rate is 57.8°/ GHz.The proposed antenna in this study has the advantages of wide band,high scan rate,and high gain,which can be applied in radar,communication and other scenarios.2.A new transmissive line-to-circle polarization conversion metasurface antenna structure was presented.The metasurface unit is composed of square patch with cut unequal diagonal angles,and the antenna polarization conversion bandwidth is expanded by using an rectangular opening ring to form two polarization conversion bandwidths and a slotting method.The simulation results show that,the return loss bandwidth of the proposed antenna is 8.24～11.30 GHz,and the bandwidth of polarization conversion is 9.45～11.30 GHz.The polarization conversion bandwidth is the widest among the similar square patch type and similar size metasurface.3.A new reflective terahertz linear polarization converter with high conversion rate was proposed.The metasurface unit is a cross-shaped structure inclined 45°,and the simulation results show that the polarization converter can achieve crosspolarization conversion in the frequency band of 404～560 GHz,and the polarization conversion rate is close to 99% in the whole frequency band,which indicates the polarization converter has the characteristics of high polarization conversion rate.