This paper presents a procedure for the design of tensorial metasurface antennas radiating polarized beams through aperture field synthesis. The aperture field is generated using the surface wave to leaky wave conversion resulting from metasurface modulation. The design procedure of the feeder is presented with a description of the geometrical parameters affecting the antenna matching. Numerical solutions for single beam and multi-beam metasurface antennas working respectively, at 12.25 and 20 GHz are presented. In addition, a metasurface prototype working at 12.25 GHz is manufactured and measured.

In order to stabilize the fast oxide ion conducting properties of the high temperature form of Ba2In2O5 at lower temperature, oxygen rich doped Ba2In2O5+δ brownmillerite were prepared by partial substitution of Ba and In with higher valence cation. Vanadium, niobium, tantalum, molybdenum and tungsten were introduced on indium site and bismuth on barium site. Solid solutions were evidenced in all the cases. They were characterized by high temperature X-ray diffraction and impedance spectroscopy. A neutron diffraction study was carried out and allowed to extract preferential oxygen pathways in these materials.