Millimeter-Wave Dual-Channel LP-to-CP Conversion Transmitarray with Independent Beam Control: (Invited)

A design method of a two-channel multiplexing transmissive Linear-to-Circular polarization converter (PC) with independent controllability is reported in this paper. In order to verify the feasibility of the design concept, sixteen kinds of anisotropic converter unit cells with linear polarization (LP) receiving and circular polarization (CP) transmitting are proposed. The Linear-to-Circular PC is enabled by introducing a length difference of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\lambda_{\mathrm{g}}/4$</tex> between the two parts of microstrip lines of the unit cell, which makes the transmission phase difference between the plane wave of transverse electric mode and transverse magnetic mode is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$90^{\circ}$</tex>. Based on the hybrid phase compensation strategy of propagation phase (PP) and geometric phase (GP), 16 kinds of cells are creatively designed, and the proposed idea is verified by forming an array. The simulation results show that the peak gain of dual CP beam is greater than 25.3 dBic, and the overlapping bandwidth of 3-dB axial ratio (AR) and 3-dB gain bandwidth is greater than 20%. The proposed transmissive Linear-to-Circular PC has the advantages of two-channel multiplexing and independent beam control, and is expected to play an important role in wireless and satellite systems.