This paper investigates the radiation properties of plasma-based intelligent reflectarray surface (IRS) that utilizes selfcomplementary elements. The elements of the surface employ reconfigurable plasma conductivity to manipulate the polarization of electromagnetic waves in various Ka-band applications. The unit-cell of the IRS is composed of 2 × 2 sub-cells of 0.5 λo × 0.5 λo × 0.078 λo mm3. Each sub-cell contains three glass containers arranged in a triangle-rectangular-triangle configuration and filled with ionized plasma gas. When the IRS illuminated by a linearly polarized (LP) plane wave, the surface converts it into circularly polarized (CP) waves based on the plasma ionization state. It achieves dual-band polarization conversion at 7.3 GHz with bandwidth of 200 MHz and at 8.6 GHz with a bandwidth of 1.15 GHz. To enhance the polarization conversion bandwidth, a sequential arrangement of self-complementary unit-cell elements with different sizes is employed. An 8 × 8 genus reconfigurable IRS is utilized to generate both left-hand circularly polarized (LHCP) and righthand circularly polarized (RHCP) waves from the upper and lower sides of the structure. The axial ratio (AR) bandwidth is maintained at 2.1 Hz for both surfaces. An LP horn antenna is used with the 8 × 8 genus reconfigurable IRS, resulting in a peak gain of 13.2 dBi, a side lobe level (SLL) of 6 dBi, and an AR bandwidth of 500 MHz. To further enhance the radiated gain, the ionized plasma within the self-complementary elements is controlled to focus the radiated power into a directive beam, resulting in an increased gain of 19.4 dBi.
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