Design of Dual-beam Orthogonal Circular Polarized Leaky-wave Holographic Antenna

In this paper, a design procedure is presented for dual-beam orthogonal circular polarized leaky-wave antenna based on the holographic technique. The hologram modulated surface is composed of anisotropic unit cells with printed elliptical patches. Variations of large and small diameters and rotation angles of patches determine the required components of the tensor surface impedance to implement the hologram. An edge-fed excitation approach is utilized to produce a reference surface wave with a planar front wave. The direction of two forward and backward object waves is arbitrarily selected. Forward pencil beams are polarized as right-hand circularly polarized (RHCP) and the other one as left-hand circularly polarized (LHCP). The dimension of the proposed structure is about $12.5\lambda_{0}\times 12.5\lambda_{0}$. The gain and radiation efficiency of the proposed antenna are about 25.7 dBi and 89%, respectively. The simulations are carried out by MATLAB and CST Microwave Studio software.