Reconfigurable Circular Polarization Van Atta Array Based on Non-Uniform Arrangement

A reconfigurable circularly polarized Van Atta array with non-uniform arrangement is proposed. The circular polarization reconfigurability of the antenna is achieved using PIN diodes embedded in the element. Each element is an aperture-coupled microstrip antenna with an impedance bandwidth of 2.9% (2.35-2.42 GHz) and a 3dB axial ratio bandwidth of 0.8% (2.39-2.41 GHz). For extending the retrodirective angle, the proposed <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1\times 8$</tex> Van Atta array is designed as a non-uniform array with a total size of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$3.92\times 0.44 \times 0.02 \ \lambda_{0}^{3}$</tex>. The -3dB beamwidth of the monostatic radar cross section (RCS) at 2.40 GHz is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\pm 54^{\circ}$</tex> for both the right-hand circular polarization and left-hand circular polarization incident waves. Compared with the uniform Van Atta array, the proposed non-uniform array has a wider monostatic RCS beamwidth at 2.40 GHz.