Research On Wide-band And Circular Polarized Dielectric Reflectarray

With the development of wireless communication technology,high gain antennas are widely used in various communication and radar systems.As a new type of high-gain antenna,the reflectarray antenna combines the characteristics of the traditional reflector and the phased array with the advantages of low profile,easy processing,simple structure,small feed loss,easy to conform and low cost.So it has great application potential.The common reflectarray is mostly in the form of microstrip.As the frequency increases,the metal loss of the metal patch increases,and the Q value of the microstrip antenna is higher and the bandwidth is narrower.Dielectric resonators,which have a low Q value,can increase the antenna bandwidth and have less loss at high frequencies.In this paper,a wideband terahertz dielectric reflectarray and a circular polarized dielectric reflectarray are proposedFirst,a wideband terahertz dielectric reflectarray is proposed which operates at 220 GHz The array element is composed of a dielectric block and a metal ground.The phase shift curve is obtained by changing the height of the dielectric block,and the height of the elements at different positions is obtained according to the phase distribution of the reflectarary.The reflectarray contains 40 × 40 elements.The incident angle and reflect angle are both 25°.The simulation results show that the gain drop is less than 1 dB between 200 GHz to 245 GHz,and the maximum gain is up to 30.7 dB.The 1 dB gain bandwidth is 20%,which is much larger than the common microstrip reflectarray.In the terahertz frequency band,processing technology greatly limits the accuracy.In this paper,3D printing technology is used to process the reflectarray with the material of nylon.The terahertz test platform is built to test the performance of the rflectarraySecond,a circularly polarized dielectric reflectarray is proposed for the first time.The array element consists of a cuboid dielectric block and a metal ground which operates at 3.4 GHz.The incident wave is linear polarized,and the reflect wave is circularly polarized.In order to decompose the incident linearly polarized wave into two components whose phase difference is 90°,the cuboid block is rotated by 45°.The reflection phase can be obtained by changing the overall size of the dielectric block.The reflectarray contains 11 × 11 elements The incident angle is 20° and reflect angle is 0°.The simulation results show that the maximum gain is 21.78 dB,and the 1 dB gain bandwidth is 9.4%.The minimum axial ratio is 0.7 dB and the 3 dB axis bandwidth is 5%.In order to verify the performance of the reflectarray,the model is modified due to the processing technology and material limitations The simulation results show that the reflectarray has a good circular polarization performance at 11.6 GHz and 12.1 GHz.In this part,3D printing technology is used to process the reflectarray with the material of photosensitive resin.