Abstract: A steerable microwave antenna includes a resonant cavity comprising a partially reflecting surface (PRS) formed of an array of transmitting-receiving cells (CF2) each of which is adapted for control in transmissivity and directivity and a totally reflecting surface (TRS). A radiating element (RE) laid within the resonant cavity is provided in the vicinity of the totally reflecting surface (TRS) so as to generate microwaves. A circuit (Bx, By) for controlling transmissivity and directivity of each transmitting-receiving cell (CF2) and of the partially reflecting surface (PRS) is further provided. Such an antenna can be implemented as an antenna for Wifi connections and cellular telephone handset.

Abstract: A steerable microwave antenna includes a resonant cavity comprising a partially reflecting surface (PRS) formed of an array of transmitting-receiving cells (CF2) each of which is adapted for control in transmissivity and directivity and a totally reflecting surface (TRS). A radiating element (RE) laid within the resonant cavity is provided in the vicinity of the totally reflecting surface (TRS) so as to generate microwaves. A circuit (Bx, By) for controlling transmissivity and directivity of each transmitting-receiving cell (CF2) and of the partially reflecting surface (PRS) is further provided. Such an antenna can be implemented as an antenna for Wifi connections and cellular telephone handset.

Abstract: The invention relates to the measurement of the granulometry of a cloud of particles or of the roughness of a surface in real time and without contact, by means of an apparatus comprising: a convergent lens (9) adapted for forming a diffraction pattern of the cloud of particles or of the surface: multiplier means (10) adatped for multiplying this diffraction pattern, in intensity, by a function f(r) such thatA(r.sup.1.5 +Br.sub.o.sup.4)<f(r)<A (r.sup.4 +Br.sub.o.sup.4)withA=constant determined by calibration of the apparatusB=constant: o<B<0.1r=distance measured in the focal plane of the lens with respect to the optical axis thereof,r.sub.o =maximum useful radius of the spatial filter,and means (11, 24) adapted for carrying out a reverse Fourier transform on the result of the above intensity multiplication, whose result forms the desired spectrum of the granulometry of the cloud of particles or the desired spectrum of the roughness of the surface.

Abstract: A process for the remote measurement of the emissivity .epsilon. of a body (1) with relatively smooth surface, consisting: in making, with a detector (6) and a converter (9), a first measurement A of the luminance at a point M on the surface at an emission angle .theta., the thermal radiation (2) on which the measurement is made being polarized (at 4) in a first direction with respect to the emission plane, in making a second measurement B of the luminance at the same point and at the same emission angle .theta., the thermal radiation being polarized in a second direction, different from the first one, finally, in determining the emissivity ##EQU1## .theta..sub.1 being the angle of the axis of the polarizer for A and .theta..sub.2 being the angle of the axis of the polarizer for B, measured with respect to a polarization perpendicular to the emission plane.