Asymptotic boundary conditions for strip-loaded scatterers applied to circular dielectric cylinders under oblique incidence

In antenna applications, strip grids can be used as polarization selective surfaces which reflect the polarization parallel with the strips and transmit the polarization orthogonal to the strips. For an accurate analysis of the strip grids we have to require that the strips are periodic and located on a simple plane or cylindrical surface. Thereafter, we would expand the scattered field on both sides of the grating in Floquet modes and apply accurate boundary conditions such that the tangential E-field is zero at the surface of each strip and continuous between the strips. This approach is not very general as it is limited to special surface shapes, and it is very laborious and complicated to implement. The purpose of the present paper is to present an asymptotic strip boundary condition (ASBC) which does not suffer from such limitations. It is simple to use in analytical work and easy to implement in existing software for analysis of radiation and scattering by using any numerical method. As an example, we apply the ASBC to derive the series expression for the scattered field of two circular dielectric cylinders, one loaded with circumferential strips and the other with longitudinal strips.