A Broadband Multi-Beam Dual-Circularly Polarized Reflect-Array for Ka-Band Application

In this paper, we proposed a multi-beam dual-circularly polarized (dual-CP) reflect-array (RA) antenna for Ka-band application. Two reflection beams fed by the right-handed (RH) CP horn point to
$\theta _{\mathrm {R}}=3.5^{\circ }$
and
$\theta _{\mathrm {R}}= -3.5^{\circ }$
at R-plane, and two left-handed (LH) CP beams fed by LHCP horn point to
$\theta _{\mathrm {L}}=3.5^{\circ }$
and
$\theta _{\mathrm {L}}= -3.5^{\circ }$
at L-plane at 30 GHz. There is a null between the two co-polarization beams to distinguish them. The reflection plane is composed of a circuit board with a size of 160 mm
$\times $
160 mm
$\times $
0.762 mm with 1304 RA cells printed on it and a metal reflection plate. The RA cells have different reflection phases with the size of 4 mm
$\times $
4 mm, based on multi-resonant structure, designed by diamonds and arrows. Measured results show that the beam directions obtained by feeding the LHCP horn and RHCP horn are the same as the design directions. The peak gain between the two co-polarized beams is very close, and the 3-dB gain bandwidth (BW) is about 25%, 2-dB axial ratio (AR) BW is up to 40%, which has broad application prospects in the long-distance and high-precision communication.