Design Of Polarization-insensitive Polarization Converter

In recent years,frequency selective surface(FSS)has become a research hotspot.FSS can be seen as a kind of periodic artificial electromagnetic structure.FSS,which usually consists of electric conductors and wave-guiding structures,can reflect,transmit,absorb or guide free space electromagnetic waves,and can be applied to space filter,radar radome,free space wave absorber and other fields.The electric conductors of FSS have the ability to sense and guide free space electromagnetic waves,based on this property,the function of FSS based polarization converter(FSS-PC)can be realized by changing the orientation of the receiving and radiating electric conductors.In this paper,six polarization-insensitive FSS-PC(PI-FSS-PC)are designed by using monopole-transmission line-monopole structures(MTM)and SIW structure to achieve polarization conversion with high efficiency for incident waves at any azimuth angle,and the equivalent circuits are put into use for analyzing frequency response.The main contents of this paper are as follows:(1)An PI-FSS-PC with two-dimensional structure is designed for achieving orthogonal conversion of electromagnetic waves.Each unit adopts two single-sided copper clad F4 B substrates,the receiving and radiating antennas each adopt four same-size monopoles.The receiving and radiating monopoles are orthogonal arranged to each other,the incident waves at any azimuth angle are orthogonal converted with high efficiency.(2)An PI-FSS-PC with three-dimensional structure is designed for achieving orthogonal conversion of electromagnetic waves.Each unit adopts a full-metal substrate,the receiving and radiating antennas each adopt four same-size inverted L antennas.The receiving and radiating antennas are orthogonal arranged to each other,the incident waves at any azimuth angle are orthogonal converted with high efficiency.(3)An PI-SIW-PC using substrate integrated waveguide structure is designed for achieving orthogonal conversion of electromagnetic waves.Each unit adopts a double-sided copper clad F4 B substrate,the receiving and radiating sides each adopt a SIW structure with 4 strip slots.The slots on receiving and radiating sides are orthogonal arranged to each other,the incident waves at any azimuth angle are orthogonal converted with high efficiency.(4)An PI-FSS-PC with two-dimensional structure is designed for achieving 90 degrees minus 2? conversion of electromagnetic waves,? is the relative azimuth.Each unit adopts two single-sided copper clad F4 B substrates,the receiving and radiating antennas each adopt two same-size monopoles.The receiving and radiating monopoles are orthogonal arranged to each other.By adjusting the azimuth angle between the PI-FSS-PC and the incident wave,the incident wave can be converted at any angle.(5)An PI-FSS-PC with three-dimensional structure is designed for achieving 90 degrees minus 2? conversion of electromagnetic waves,? is the relative azimuth.Each unit adopts a full-metal substrate,the receiving and radiating antennas each adopt two same-size inverted L antennas.The receiving and radiating antennas are orthogonal to each other.By adjusting the azimuth angle between the PI-FSS-PC and the incident wave,the incident wave can be converted at any angle.(6)An PI-FSS-PC with two-dimensional structure is designed for achieving 2? conversion of electromagnetic waves,? is the relative azimuth.Each unit adopts two single-sided copper clad F4 B substrates,the receiving and radiating antennas each adopt two same-size monopoles.The receiving and radiating monopoles are 0 or 180 degrees arranged to each other.By adjusting the azimuth angle between the PI-FSS-PC and the incident wave,the incident wave can be converted at any angle.