Abstract: A microwave array antenna comprises a plurality of like unit sources whose width increases progressively from the center of the array towards its ends and which are disposed relative to each other in such a way that substantially no illumination gaps are created in the array.

Abstract: An offset type active antenna having two reflectors in a periscopic configuration. A radio lens is provided at the focii of the two reflectors. It comprises a collector and a primary array that is considerably larger in size than the collector. The "small" sources of the collector are in a geographically identical one-to-one correspondence with the "big" sources of the primary array, and they are respectively connected together via devices for providing fine phase adjustment.

Abstract: An analog variable phase shifter comprises a phase shift circuit and associated active inlet and outlet matching circuits. The phase shift circuit includes a transistor with negative feedback, and the inlet and outlet matching circuits are of the type used for matching a wideband microwave signal amplifier over the entire range of frequency variation in the microwave signals applied to the amplifier.

Abstract: The invention relates to a reconfigurable transmission antenna comprising a reflector (10) for energy focussing, and an array (11) of source elements situated in the focal region of the reflector, so that the electromagnetic field is synthesized in said region, wherein a spot (SPi) is the result of radiation from a number of sources that is fixed and identical for all the spots; any one source participating at any one time in radiating one spot at the most, and high-level switching being used to reconfigure the spots by selecting the sources that participate in a given spot. Application to the space telecommunications field in particular.

Abstract: Satellite radar apparatus measures the backscatter coefficient of the sea to determine the speeds and directions of winds at sea. The apparatus implements three aiming directions per swath with the track thereof on the Earth being parallel. The radar technique used operates by pulse compression, and on reception noise is measured in parallel with the measurement of signal plus noise. The apparatus includes an assembly for calibrating the product of transmission power multiplied by reception gain, which assembly includes a servo-control loop connected to the transmission line via a directional coupler.

Abstract: A test apparatus for testing equipment in motion comprises a test device (1) for testing a piece of equipment (2) and a mobile enclosure (3) containing a gas lighter than air and surrounding the test equipment (2) located on the test device (1).

Abstract: Spacecraft payload architecture which includes an array (10) of radiating elements preceded by an amplification stage (17) and a focusing optical system (11), characterized in that the architecture is adapted to a telecommunication mission by taking into account the overall requirements of the system, namely the radiation performance required for the mission, efficient rating of the amplification stage and attractive overall balances.

Abstract: A microwave equalizer is used in aerospace applications to correct the gain/frequency response of a microwave system, in particular in a given range of temperatures. To obtain a variation opposite to that of the microwave system by introducing absorption at the operating frequency, it comprises at least one microwave coupler one branch of which has an active device fitted at each of its two ends so that variation in the device parameters enables displacement of the absorption frequency and optionally power. The coupler(s) are coupled to a transmission line of the system and a control circuit.

Abstract: A microwave antenna element suitable for constituting one of the elements of an array, the antenna element being capable of transmitting or receiving two orthogonally-polarized microwaves. The antenna element is constituted by a cavity containing two orthogonal excitation probes separated by a polarization-selective obstacle forming both a short-circuit plane for the microwave transmitted by the top probe, and also a patch for the microwave transmitted by the bottom probe. Another patch is common to both of the interlaced antennas. A third patch which is polarization-selective in the sense that it is transparent for the microwave transmitted by the bottom probe, may also be provided.

Abstract: The invention relates to a structure for making microwave circuits and components, in which the mechanical and electrical functions are integrated overall but dissociated locally. The invention is particularly suitable for space applications.

Abstract: The present invention relates to a multifrequency antenna comprising a microstrip patch first antenna (10, 11, 12) operating at one or more frequencies, and a second antenna (17) disposed in front of the antenna and using the same radiating surface and operating at a different frequency. The invention is applicable, in particular, to space telecommunications.

Abstract: An amplifier device has a gain programmable between 2.sup.n and 2.sup.n-1 in steps of 2.sup.p where p<n and n is the number of gain control bits. The device comprises a plurality of stages having two gain values selectable by a control bit and at least two identical stages having a different control bit. Each stage has a maximum gain less than 2.sup.n-1.

Abstract: The present invention relates to a stripline microwave module comprising: at least one first line situated in a first plane; at least one second line; and at least one coupling opening situated in a second plane so as to enable transmission to take place between the two lines. The invention is particularly suitable for space applications.

Abstract: A high-efficiency active printed-circuit antenna system for pulsed frequency-hopping space radar electronically scanned in two planes encompasses in its timing diagram the transmission of a horizontal polarization pulse, the reception of echoes from a previous horizontal polarization pulse, the transmission of a vertical polarization pulse and the reception of echoes from a previous vertical polarization pulse. The system comprises several thousand MMIC modules distributed over the antenna and each connected to a printed-circuit radiating element comprising a plurality of dual polarized square patches connected by microstrip lines which excite them with the same amplitude and the same phase at two perpendicular ports. Switching between the two ports procures transmission or reception with horizontal or vertical polarization.

Abstract: A phase-locked loop demodulator comprises a mixer and a loop filter between an input and an output. A voltage-controlled oscillator is connected between its output and an input of the mixer. The demodulator further comprises a lock-on detector circuit whose output signal is adapted to increase the static loop gain after lock-on by modifying the characteristics of the filter.

Abstract: A device for measuring a multipactor effect in microwave systems includes a first coupler, a vacuum enclosure where a sample under test is enclosed, and a second coupler, all in series between an input which receives incident power and an output which delivers output power. The device also includes a mixer operated as a phase detector having a first input connected to an output of the first coupler to sample part of the input power via a first attenuator and a phase-shifter and a second input connected to an output of the second coupler to sample a part of the output power via a second attenuator. The output of the mixer is connected to a noise measuring device.

Abstract: A satellite transponder has the local oscillator in the receiver slaved to a quartz crystal oscillator by a narrowband phase-locked loop during a standby period or in the absence of received signal and by a wideband phase-locked loop immediately the signal is received, at which time the narrowband phase-locked loop is switched out automatically.

Abstract: A dual-gate field effect transistor attenuator wherein a variable active load (1) is applied to the second gate of the dual-gate field effect transistor (T1). The attenuator is particularly suitable for space telecommunications.

Abstract: A method of controlling a chopper regulator, which method is a time-varying parameter-regulation method having a very wide passband and controlling energy at each instant, in which the stable state of the system at the following sample is predicted, thereby making it possible to achieve regulation under very good safety conditions. A circuit for implementing the method is also disclosed. The invention is particularly suitable for space applications.

Abstract: A circuit for regulating a parameter by means of a bidirectional current chopper structure suitable for transferring energy from an input network to an output network via the bidirectional current chopper structure, the current flowing through the structure being in the form of a triangular wave. The circuit is particularly suitable for space applications.