Improved retrodirective flattened dihedral using incidence angle correction

In this paper, a study on a flattened dihedral using reflect array approach is presented and a method is proposed to improve its performance. The dihedral-equipped with phase-shifting cells-obeys the retro directive phase law to redirect the wave back in the same direction of incidence. This retro-law is derived in function of the geometry parameters and plane wave incidence angle using simple trigonometric relations. It is shown that the reflected signal from the first panel hits the other panel with very oblique incidence angle. Due to that, the phase responses of the cells-designed using the classical normal incidence setup-get deteriorated to the extent they no more obey the required phase law. Upon this information, new setup is proposed to enhance the functionality of the cells and hence enhance the retro directive behavior of the dihedral at 24 GHz. Simulations using Ansoft
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HFSS software have been performed to validate this method.