Transmission Property of Dielectric Phase Gratings with Stepped and Curved Profiles

Grooved dielectric phase gratings are commonly used for transferring millimeter or submillimeter wave power generated by an array of active sources into a pseudo-plane wave which is further reconstructed as a main Gaussian beam to fulfill power combination. Modified grooved dielectric gratings with multi-step or curved profiles have more degrees of freedom for adjusting the phase of exciting Gaussian beams to form a pseudo-plane wave. In this paper, the transmission property of the modified dielectric gratings is analyzed by a hybrid technique of finite element method (FEM) and Gaussian mode expansion method. The transmitted field through the modified dielectric gratings is calculated. Numerical results of transmission coefficients are presented for the gratings with different profiles at D-band.