Université Grenoble Alpes, Grenoble, France, CEA LETI, MINATEC Campus, Grenoble, France, Space Engineering S.p.A. (Airbus Group), Rome, Italy, Direction Générale de L'Armement, Strategy Dir., Office for Advanced Research and Innovation, Bagneux, France, CEA LETI, MINATEC, Grenoble, France, Institute of Electronics and Telecommunications of Rennes, University of Rennes 1, Rennes, France, Direction Générale de L'Armement, Bruz, France

The design, realization, and experimental characterization of a 400-element electronically reconfigurable transmitarray operating in the Ka-band is presented. It is based on linearly polarized unit-cells with 180° phase-shifting capability. Several sequential rotation schemes have been compared numerically to generate a circularly polarized beam over a broad frequency band, and a random distribution has been selected to mitigate spurious cross-polarized side-lobes when scanning the main beam. The 2-D electronic beam-steering capabilities of ±60° have been verified experimentally. The prototype, illuminated by a horn antenna as a focal source, exhibits a broadside gain of 20.8 dBi at 29.0 GHz and a 3-dB bandwidth of 14.6% with radiation efficiency of 58%. The axial ratio remains below 2 dB within this bandwidth. Next, a planar substrate integrated waveguide focal source array was designed in order to reduce the focal distance by about 50% and thereby significantly improve the antenna compactness, and similar radiation performance is demonstrated numerically and experimentally. © 1963-2012 IEEE.

Beam steering, circular polarization (CP), discrete lens, planar lens, reconfigurable antenna, transmitarray

Antenna lobes, Bandwidth, Circular polarization, Frequency bands, Lens antennas, Microwave antennas, Phase shift, Polarization, Substrate integrated waveguides, Waveguides, Beam-steering, Discrete lens, Planar lens, Reconfigurable antenna, Transmit arrays, Horn antennas