Tunability and sign-switching of deflection angle in diffraction inspired unidirectional devices

An asymmetric transmission device based on sub-wavelength stacked hole arrays (SHA) backed with a dielectric grating is presented. The combination of diffraction modes with the dispersion characteristics of the SHA leads to very interesting electromagnetic properties such as unidirectionality, tunability and sign-switching of the outgoing wave deflection angle with just varying the angle of incidence of the impinging wave and/or changing the frequency of operation. A brief theoretical discussion, numerical results and experimental results in the V band of the millimetre-waves are provided for demonstration of the performance.