Wideband Dielectric Lens Antenna With Stable Radiation Patterns Fed by Coherent Array of Connected Leaky Slots

A broadband reflector feed is presented, which consists of a dielectric extended hemispherical lens fed by a connected array of leaky-wave slots. The slot elements are coherently combined to generate directive radiation patterns that mostly illuminate the central part of the lens, the most efficient one. The array is capable of producing secondary patterns with almost constant -10 dB beamwitdh over a 3:1 bandwidth. This allows efficient illumination of the reflector over a wide frequency range. Performance is estimated in terms of amplitude taper and phase error losses at the reflector, yielding efficiency of about 80% over the entire 3:1 bandwidth. Although the envisaged applications are in the terahertz (THz) and mm-wave frequency bands, a low-frequency prototype demonstrator has been tested in the 4 to 12 GHz band, for experimental validation of the concept.