Off-Bragg Blazed Rectangular Groove Gratings for High Diffraction Efficiency Devices

Off-Bragg blazing of gratings for high efficiency frequency scanning antennas, multiplexers and demultiplexers, is described. Blaze angles occur in pairs and are related by a generalization of the Bragg condition applicable to all grating profiles. Off-Bragg blazing for TM polarization occurs for several perfectly conducting grating profiles, perhaps for all, as indicated by extensive numerical computations using a rigorous mode matching method on a perfectly conducting rectangular groove reflection grating. Design curves for groove dimensions which have high diffraction efficiencies and wide deviations with relatively shallow grooves are given.