Abstract: The invention provides a device including a radial combiner for electromagnetic waves and a method using a radial combiner. The invention provides a radial combiner with resistors disposed between the impedance matches capable of combining these signals from a plurality of radially disposed amplifiers or transmitters. By applying desired phase shifts to the signals transmitted by certain amplifiers or transmitters, amplitude-phase modulation of the total signal transmitted can be provided. It is more particularly possible to provide radar pulse modulation for reducing the frequency spectra of the transmitted signal.

Abstract: The apparatus according to the invention relates to a guided vehicle control process and apparatus which comprises passive beacons, as well as radars permitting the detection thereof. The presence or absence of a beacon permits the automatic control of a train, e.g. with a view to automating the driving thereof. The apparatus according to the invention uses retrodirectional beacons and/or beacons inducing a polarization rotation of the radiation received. The use of retrodirectional beacons induces a change of frequency by Doppler effect of the reflected radiation. The change of the Doppler frequency and/or the polarization rotation of the radiation improves the signal-clutter ratio and/or the separation of the transmission and reception channels.

Abstract: A passive duplexer for electromagnetic waves operated within the millimetric wave range. The duplexer comprises a first horn associated with a radar transmitter and having a propagation axis (.DELTA..sub.1), a plane circular grid inclined at 45.degree. with respect to (.DELTA..sub.1), and a second horn associated with the radar receiver and having an axis (.DELTA..sub.2) at right angles to (.DELTA..sub.1). The grid is formed by a network of resonant slots equipped with at least one diode.

Abstract: An electromagnetic wave switch is provided formed from a profiled wave-guide associated with a PIN diode, filling completely the profiled part of said guide, having a high breakdown voltage and a low thermal resistance.

Abstract: The passive limiter is formed by at least two parallel micro-strip lines, a slot line orthogonal to the two micro-strip lines and a pair of diodes having the same polarity and placed on each edge of the slot line facing one another, the assembly of these three lines and the diodes forming at least two micro-strip line-slot line transitions.

Abstract: A four-state phase shifter for UHF waves comprises two O-.pi. phase-shifting elements of planar structure on a common substrate, these phase-shifting elements including a symmetrical and an asymmetrical transmission line which can be selectively coupled in one of two ways by the alternate blocking and unblocking of respective diodes for a relative phase reversal. The two phase-shifting elements are linked by two further transmission lines of different propagation constants which can be selectively activated, again with the aid of diodes, and which may be disposed on opposite faces of the substrate or may form part of a coplanar conductor array on the same substrate face.

Abstract: A microstrip line, formed on a dielectric substrate by a conductor strip and a ground-plane layer or a pair of flanking coplanar layers, is electrically coupled to a slot line on that substrate with the aid of supplemental conductors establishing alternate microwave transmission paths between a terminal portion of the strip and respective slot edges. The supplemental conductors include a pair of diodes which are rendered selectively conductive to unblock one or the other transmission path, thereby enabling a 180.degree. shifting of the phase of oscillations transmitted by the slot line to a load upon energization of the microstrip line by a source of microwaves. The load may be a radiating element of an electronically scanning antenna.

Abstract: A microstrip line, formed by a conductor strip on one side of a dielectric substrate and by a ground-plane layer on the other side thereof, is electrically coupled to another microwave-transmission line, formed by a slot in the ground-plane layer paralleling the strip, with the aid of a supplemental conductor element establishing a virtual short-circuit at an off-axial location on a portion of the strip overlapping the slot. The supplemental conductor element may be a wire, traversing the substrate, or a lateral extension of the strip defining an open-circuited quarter-wavelength line with the ground-plane layer.

Abstract: This invention relates to an apparatus and a method for determining the concentration of a first reactant in a medium. A disc is saturated with a solution containing the first reactant and immersed into a second reactant fluid. A chemical reaction occurs between the first and second reactants to produce a gas which is trapped by the disc. The disc is buoyed to the surface of the second reactant fluid by the gas produced. The process is electronically timed using photocells to start and stop an electronic clock and a digital display displays the time elapsed in tenths of seconds.

Abstract: An apparatus and a method for determining the concentration of a first reactant in a medium. A disc is saturated with a solution containing the first reactant and immersed into a second reactant fluid. A chemical reaction occurs between the first and second reactants to produce a gas which is trapped by the disc. The disc is buoyed to the surface of the second reactant fluid by the gas produced. The process is electronically timed using photocells to start and stop an electronic clock and a digital display displays the time elapsed in tenths of seconds.