Monopulse 77GHz Fresnel Zone Plate reflector

This paper describes the principle of combining circular or annular patches with C-patches on a Fresnel reflector. The latter can introduce radiation pattern diversity according to the polarization. Patches are designed to perform a 180deg phase difference of the reflection phase between two orthogonal polarizations for a monopulse antenna purpose. Simulations on a small half-wavelength Fresnel zone plate (FZP) reflector have been conducted in order to check the antenna concept. The final antenna will include a (2pilambda/8) Fresnel correction, i.e an 8 zones Fresnel reflector. C-patches have already been designed at 77 GHz and the reflector measurements have been conducted.