Wide-Band/Angle Blazed Dual Mode Metallic Groove Gratings

TL;DR

This paper presents a novel design for metallic gratings that achieve wide-band and wide-angle blazing by supporting two guided modes, verified through circuit analysis and full-wave simulations, enabling efficient power transfer over a broad frequency range.

Contribution

It introduces a simple, circuit-based approach to design wide-band/angle blazing metallic gratings supporting dual guided modes, with explicit parameters and analytical modeling.

Findings

Achieves 50% fractional bandwidth at 10 GHz

Transfers power efficiently to the -1 diffraction order

Validated models with full-wave simulations

Abstract

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 (TM) 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 (TM) 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.