Lmt Radioprofessionnelle

Imt Radio Professionnelle

L.m.t. Radio Professionelle

Maurice Marchand

Yan Haentjens

Christian Petitjean

Alain Cornu

Christian Petijean

Alain Menestreau

Richard Le Brun

Alain Carof

A flat, self protected and transportable lattice is provided using a radiating structure formed of a three-plate line, with sources forming a lattice etched on one of the conducting planes. This structure further comprises two identical foam sheets bonded by an adhesive which allows sliding in the two conducting planes of the radiating structure, each foam sheet being covered with a thin rigid bonded plate. The plates thus bonded are chosen transparent to the radiation and form a symmetrical structure whose inherent flatness and rigidity are ensured, which is self protected and which is also sealed by means of a banding system.

Self protected and transportable flat lattice antenna

The invention concerns beacons associated to radars. It consists in modulating the re-emitted signal, in phase by the frequency of a vocal signal, and in amplitude by the envelope of this signal. It allows vocal transmission between such a signal and a Doppler radar.

Passive radar responder

A coherent radar including separate transmitting and receiving chains. The transmitting chain includes a master oscillator providing a signal at frequency F0. A multiplier multiplies F0 by a predetermined amount to produce a signal at a frequency F1. A second multiplier multiplies the signal at frequency F1 to produce a signal at frequency F2, F1 and F2 being coherent with F0. A first mixer mixes F1 with F0 and a second mixer mixes F2 with the product of the first mixer to produce a transmission signal. In the receiving chain, a received signal is amplified and filtered and then mixed in a third mixer with the second signal at frequency F2 from the transmitting chain. The mixing product of the third mixer is amplified and filtered and mixed in a fourth mixer with the first signal. The fourth mixer product is then coupled to a processor for producing a radar display.

Coherent radar

In a microwave preamplifier of a Doppler radar system used for Earth observation, three pre-matched and self-biassed field effect microwave transistors are provided. By supplying these transistors by means of a voltage regulator, whose output voltage varies under the action of a control circuit, the gain of this pre-amplifier may be varied without modifying the standing wave ratio, thereby obtaining modulation of the microwave signal amplified by the amplifier. Thus, additional modulation may be obtained, speech modulation for example, on the transmission signal of an Earth observation Doppler radar system.

Field effect transistor microwave amplifier

In a microwave power transmitter for Doppler radars for terrestrial surveillance, use is made of four stages in series comprising first and second preamplifiers, and first and second power amplifiers. These stages are supplied by a group of separate voltage regulators. These regulators are controlled by a control circuit which makes it possible to cut off the stabilized voltage between instants of transmission, that is to say between microwave pulses of a radar signal. A feedback device makes it possible to stabilize the output level by causing variation of the gain of the first preamplifier by means of its supply voltage.

Microwave power transmitter for doppler radar

An up converter having on the one hand an ultrahigh-frequency ring receiving one of the waves to be mixed and on the other hand a transformer receiving the other wave to be mixed whose frequency is in the radio-electric range. The transformer is connected to the ring through a bridge of mixer diodes which are placed with this transformer and a capacitor for tuning this latter inside the ring. The resulting wave exits from the ring through a waveguide having two traps tuned to the frequency of the wave applied to the ring.

Microwave up-converter

A mixer comprising two microstrip plates, each having an earth plane, a dielectric layer and an etched layer. One of the etched layers carries the mixer ring and input guides. The outer etched layer carries the output guide and the tuning members. The plate are joined by their earth planes and the mixer diodes are placed in the holes connecting the two etched faces.

Growing community of inventors

Boulogne Billancourt, France

Maurice Marchand