Abstract:
The asymmetric transmission (AT) is used for directional control of electromagnetic (EM)
waves. To achieve the broadband AT behavior, the bi-layered chiral metasurface (CMS)
structure is used for linearly polarized electromagnetic waves in microwave and optical regime.
To obtain the chirality, high cross-polarized transmission coefficient i.e., > 90% is necessary
which is dependent on the EM coupling between upper and lower metallic layers of
metasurfaces.
In this thesis, a CMS structure is designed & developed to achieve the AT behavior. The
proposed design consists of a square split-ring resonant printed on the upper layer. At the
bottom layer, the same design is printed by flipping and rotating it at an angle of 90o
to achieve
chirality in the structure. The AT is operated from 13.38-16.88 GHz with fractional bandwidth
of 23.13%. Over the 3.5 GHz bandwidth, a transmission efficiency of 90% and an AT
magnitude greater than 0.8 are attained. Moreover, the response of the metasurface does not
vary against oblique incidences up to 50o
. Hence, the proposed design of a bi-layer structure of
metasurfaces has characteristics of angular stability with high efficiency AT in linear
polarization which make it suitable for different types of application like polarization control
devices, microwave, and modern telecommunication devices.
