  In recent years, there has been extensive research on planar metasurfaces
capable of arbitrarily controlling scattered fields. However, rigorous studies
on conformal metasurfaces, such as those that are cylindrical, have been few in
number likely due to their more complex geometry. Here, wave propagation in
cascaded cylindrical structures consisting of layers of dielectric spacers and
azimuthally-varying metasurfaces (subwavelength patterned metallic claddings)
is investigated. A wave matrix approach, which incorporates the advantages of
both ABCD matrices and scattering matrices (S matrices), is adopted. Wave
matrices are used to model the higher order coupling between metasurface
layers, overcoming fabrication difficulties associated with previous works. The
proposed framework provides an efficient approach to synthesize the
inhomogeneous sheet admittances that realize a desired cylindrical field
transformation. Design examples are reported to illustrate the power and
potential applications of the proposed method in antenna design and stealth
technology.
