Wide-Band/Angle Blazed Dual Mode Metallic Groove Gratings

We introduce a new and simple approach to acquire wide-band/angle blazing operation in one-dimensional metallic gratings supported by equivalent circuit analysis. The gratings that are investigated here are single-groove gratings that support two propagating guided modes. It is shown that under such operating conditions, one can achieve blazing over a wide range of frequencies and angles. Parameters of the proposed equivalent circuit model for the case of the transverse magnetic ™ polarization are analytically derived. The accuracy of the models is verified through comparison against results of full-wave simulations. The procedure to achieve wide-band/angle blazing performance is delineated and the design parameters are explicitly given. It is shown that this structure is able to strongly transfer the power of the transverse magnetic ™ polarized incident wave to the -1-th diffraction order with a fractional bandwidth of 50 % at working frequency f_0 equal to 10 GHz and for -10 dB specular reflection loss, thus realizing a broadband structure. From the circuit model, an insightful discussion is presented at various mechanisms at play, when Bragg and off-Bragg blazing occurs and fully justifies the behavior of the device. The proposed technique opens up new vistas in a wide range of applications such as spectroscopy, Littrow cavities, beam splitters, and frequency scanned antenna reflectors.