Design Of Polarization Manipulation Metamaterial Device Based On Substrate Integrated Waveguide Technology

Metamaterials are artificial materials that have unique physical properties compared to natural materials.The amplitude,phase and polarization of electromagnetic wave can be manipulated flexibly by designing the unit structure of metamaterials,changing the size or arrangement of metamaterials.Metamaterials are widely used in the research of polarization converters because they can control or change the polarization direction of electromagnetic waves.Traditional polarization converters have shortcomings in bandwidth,efficiency and other performance aspects.To obtain better performance,the structure design is often more complex and the cost is high.Therefore,the realization of transmission polarizer with miniaturized and low cost has aroused great interest of researchers.The frequency selective surface has good frequency selectivity and polarization rotatability.The polarization converters based on frequency selective surface are widely used in satellite communication,quasi optics and radio astronomy,etc.The substrate integrated waveguide has the advantages of low loss,high quality factor and high power of both microstrip and rectangular waveguide.The polarization manipulation device is designed by combining the frequency selective surface with the substrate integrated waveguide,which improves the performance of the device and reduces the size and manufacturing cost of the device.In addition,the unit structure of the device is rotated to adjust the transmission phase,so that the stable phase difference can be generated between the units.By encoding different phase units and designing different array combinations,the beam control can be realized.Therefore,the research of polarization manipulation metamaterial device based on the substrate integrated waveguide technology has broad application prospects.(1)A triple-band metamaterial polarization converter based on substrate integrated waveguide technology is proposed.By combining the transmission frequency selective surface with the substrate integrated waveguide resonant cavity,and taking advantage of the advantages of the substrate integrated waveguide technology,such as low loss,high quality factor,high power and so on,a transmission linear polarization converter is designed.The orthogonal linear polarization conversion can be achieved in the three frequency bands of 7.99GHz-8.16GHz,13.09GHz-13.89GHz and 16.42GHz-17.04GHz,and the polarization conversion rate reaches more than 95%.The polarization conversion mechanism of the device is analyzed according to the electric field distribution at the resonant frequency and the equivalent circuit model of the polarization converter,and the effects of different structural parameters on its resonance characteristics are discussed.The proposed polarization converter is measured experimentally.The transmission coefficient of polarization conversion is observed and compared with the simulation results.The actual measured results are in good agreement with the simulation results.(2)A coding metamaterial based on the substrate integrated waveguide technique is presented.A wide-band transmission type linear polarization converter is proposed,which consists of three layers of copper-clad plates etched with Z-shaped slits,each layer rotates 45° along the z-axis and is surrounded by the substrate integrated waveguide cavity.Orthogonal linear polarization conversion is achieved in the range of 7.59GHz-9.56GHz frequency band,the polarization conversion rate is more than 90%,and the transmission bandwidth of the polarization converter is increased by using the integrated waveguide cavity.Afterwards,a coding metamaterial is proposed based on the above structure,the transmitted beam can propagate in the direction of +30°and-30°respectively.