基于特征模分析的宽带圆极化超表面缝隙耦合天线OA

Based on the characteristic mode theory,a low-profile metastructure circularly polarized broad-band slot-coupled microstrip antenna is proposed.The metasurface is composed of a 4×4 cut angle metal patch,the antenna is fed by gap coupling,and the floor gap consists of a double trapezoidal connection.Based on the theory of characteristic mode,the function of degeneracy mode of square radiating patch is analyzed,and the degeneracy mode is separated effectively,which provides the mode basis for realizing circular polarization broadband performance.The size of the antenna is 0.67λ×0.67λ×0.043λ,where λ is the free-space wavelength at 5.0 GHz.The simulation results show that the-10 dB impedance band-width is 29.8％for frequencies from 4.33 GHz to 5.82 GHz and the 3 dB axial ratio bandwidth is 17.8％for frequencies from 4.93 GHz to 5.82 GHz.This antenna achieves good circularly polarised broadband performance and has excellent application prospects in areas such as satellite communications.