A Wideband Multifunctional Polarization Converter with Low Loss and High Isolation

A reconfigurable wideband polarization converter with low insertion loss (IL) and high isolation is proposed in this paper, which is based on active metasurface. By controlling the working states of added PIN diodes, the polarizer can maintain the polarization state of incident waves and convert linearly polarized (LP) waves to its cross-polarized waves, left-handed circularly polarized (LHCP) or right-handed circularly polarized (RHCP) waves. The IL is less than 1 dB and the isolation is greater than 70 dB during polarization-maintaining. As a linear-to-linear (LTL) polarizer, the minimum IL and the maximum isolation is 0.45 dB and 44 dB, respectively. The relative 3-dB axial ratio (AR) bandwidth is 43.95% when the polarizer works as a linear-to-circular (LTC) polarizer. Besides, the polarizer can maintain the stability with the incident angle from 0 to 20°. The overlapping band of four functions is 4.42-6.91GHz. The multifunctional polarizer can be widely used in practical applications, such as providing multiple transmission channels for frequency reuse.