Abstract: An optronic porthole comprises a substrate with two faces. It comprises on one of the faces of the substrate or on both faces, a stack of several hetero-structures, each hetero-structure being composed of at least two semi-conducting layers SC1, SC2, the layer SC1 being doped, the layer SC2 itself comprising a two-dimensional electron gas layer formed at the interface with the layer SC1. It furthermore comprises an electrode in contact with all the electron gas layers, a bi-periodic metallic grid buried in the stack, in contact with the electrode. The substrate and the layers are transparent in the 0.4 ?m-5 ?m band.

Abstract: An optronic porthole comprises a substrate with two faces. It comprises on one of the faces of the substrate or on both faces, a stack of several hetero-structures, each hetero-structure being composed of at least two semi-conducting layers SC1, SC2, the layer SC1 being doped, the layer SC2 itself comprising a two-dimensional electron gas layer formed at the interface with the layer SC1. It furthermore comprises an electrode in contact with all the electron gas layers, a bi-periodic metallic grid buried in the stack, in contact with the electrode. The substrate and the layers are transparent in the 0.4 ?m-5 ?m band.

Abstract: The invention relates to a ferrite material of garnet structure based on yttrium and iron and containing copper, which makes it possible for its sintering temperature to be substantially lowered compared with the conventional ferrite materials of garnet type which satisfy the following chemical formula: YaREbFecAldIneCafCugZrhViCojSikO12±? where RE: is a rare earth or a combination of rare earths and 3(a+b+c+d+e)+2(f+g+j)+4(h+k)+5i=24±2? 1?a?3.5; 0?b?1.5; 4?c?5; 0?d?1.5; 0?e?0.8; 0?f?1; 0?g?0.05; 0?i?0.8; 0?j?0.5; 0?k?0.5. The invention is useful in the following applications: microwave components, low-loss inductive passive components operating at frequencies of the order of gigahertz.

Abstract: A composite magnetic material showing reduced losses and reduced permeability when it is subjected to a magnetic field at frequencies below approximately 100 MHz. It comprises magnetic particles in the form of wafers dispersed in a dielectric binder. The polycrystalline magnetic ceramic wafers are oriented so that their main faces are substantially parallel to the magnetic field.Application especially to cores of inductors or transformers.

Abstract: A magnetic core includes a body made of polycrystalline ceramic and at least one localized gap made of a composite magnetic material. The gap may be preferably fixedly joined to the body by bonding or molding. The magnetic core has applications in inductors or transformers. The inductor preferably has a coil located on the body, which coil is preferably made of multistranded enameled wires.