Analysis of artificial multiplexed microwave holograms for beam splitting

Artificial or complex media have attracted much attention lately due to their controllable or reconfigurable properties that allow advanced applications in antenna systems where natural materials may not meet the requirements. A recent example of such structures is artificial microwave volume holograms (AMVHs) (Shaker, J., Electronics Lett., vol.39, p.1701-2, 2003; Zhu, W. et al., Microwave & Optical Tech. Lett., vol.43, no.5, p.390-4, 2004), where planar lattices of metallic disks are printed on dielectric slabs and the latter are cascaded to form a 3D lattice structure. Unlike conventional printed disk media or artificial dielectrics, AMVHs have periodically-varying-size patches at lattice nodes to simulate the effective permittivity modulations required as holograms. With AMVHs, many techniques based on the holographic concept in optics can be migrated into the microwave regime. The paper describes briefly the design of multiplexed AMVHs for electromagnetic beam splitting and combining. The scattering characteristics and beam splitting behavior are analyzed using both the dipole-dynamic-interaction and the coupled-wave theories. One of the potential applications of such devices is in spatial power combiners.