Effect of Resonance Phenomena on the Axial Focusing Properties of Inclined Dielectric Lens in Horn Antenna

A millimeter-wave horn antenna with an external dielectric lens is considered. It has been experimentally shown that the rotation of the lens around an axis perpendicular to the longitudinal axis of the antenna system leads to an increase in the signal level at the antenna receiver. A simplified two-dimensional model of the system is developed on the base of FDTD method implemented in the MEEP package. The simulation results indicate a change in the axial focusing of the lens when it is rotated. It has been established that the main physical mechanism that causes an increase in the signal level at the antenna receiver is resonant phenomena in the volume of a dielectric lens. These phenomena are similar to the well-known half-wave resonances in a plane-parallel plate with oblique incidence of a plane wave.