Transformation-optics antenna lens design using complex coordinate transformation

In this paper, we present an effective approach to design antenna lenses for controlling the far-field patterns, which only uses a single electromagnetic source or antenna feed located outside the lens. By employing a complex coordinate transformation, a spatial distribution of gain and/or loss can be introduced into the lens. Consequently, the proposed approach offers an extra degree of freedom that allows for controlling not only the phase distribution of the electromagnetic field inside the lens but also its amplitude distribution. Several full-wave simulated lens examples and corresponding linear antenna array calculations are presented, showing the capability of complex transformation optics for far-field pattern manipulation and near-field amplitude tapering across the lens aperture.