DEVICE Of EMISSION RADIO FREQUENCY

The present invention relates to a device for radio frequency transmission, the type of transmission having:

-a source of electromagnetic radiation;

-type network having a emission axis; and

-a duct guiding the electromagnetic radiation of the source to the antenna.

Devices are known which RF transmit very high power antenna a source of electromagnetic radiation, such as a magnetron high power.

The antenna is generally rigidly connected to the source of electromagnetic radiation, itself rigidly connected to its high voltage power supply. Therefore, it is not possible to change the transmitting direction of the antenna without rotating the entire device.

In order to change the emission direction of an antenna of a transmitting device, it is known also additionally make movable the antenna with respect to the radiation source by means of a movable support and power required thereby making the existence of a guide conduit or waveguide angularly deformable for routing of electromagnetic flux from the source to the antenna. The deformation of the waveguide requires the use of complex mechanisms as much as the vacuum flow is to be guided. The joints for the deformation of the waveguide are often the cause of breakdown phenomena and are therefore not suitable for very high powers or to the very large deflections.

The document US 4,862 185 describes a system for aiming which the main beam radiated is capable of describing a cone of revolution about an axis of rotation. However, the proposed system comprising a transmitting antenna incorporating a reflector, is a little mismatched compact and high power.

This problem has been partially solved in the document US 6,259 415 in the case of an antenna network using a fixed misalignment of the radiated beam with respect to the axis of the antenna, and a rotating seal for the beam describe a cone of revolution about the vertical axis. However, the proposed system includes a mechanical device enabling a clearance mechanical antenna ° ± 25 requiring flexible coaxial cable link for feeding the antenna network. Such a system is not adapted to the high power due to limitations in breakdown of such a link.

The object of the invention to provide a radio frequency transmission device for use in an arrangement where the direction of the field radiated by the antenna is angularly movable, with reduced risk of breakdown.

To this end, the invention relates to a device for radio frequency transmission of the aforementioned type, characterized in that the antenna is rotatable relative to the source of radiation about an axis, which axis is angularly displaced from the emission axis, and in that the guide conduit has a first guide extending along the axis of rotation of the antenna and rigidly connected to the antenna.

In particular embodiments, the radio frequency emitting device comprises one or more of the following characteristics, taken alone or in combination:

-the antenna is rotatable about an auxiliary axis angularly displaced from the axis of rotation of the antenna;

-the conduit has a second waveguide extending along the auxiliary axis connected to the source of electromagnetic radiation and to the first waveguide;

-the guide conduit has a fixed angular aperture bend waveguide connecting the first and the second waveguide;

-the axis of rotation of the antenna forms an axis of revolution of the antenna;

-the axis of rotation of the antenna and the auxiliary axis are concurrent;

-the device comprises a rotating seal connecting along the axis of rotation of the coaxial antenna two consecutive sections of the first waveguide;

-the guide conduit is adapted to that the electromagnetic radiation propagating from the source to the antenna of a magnetic transverse mode TM₀ i; and

-the device comprises a mode converter on the exit of the source or inlet of the antenna so that the electromagnetic radiation propagates according to the transverse mode TM magnetic₀ i from the source to the antenna.

The invention be included at the reading the description which will follow, given by way of example only and made by referring to the sole figure appended, which is a perspective view of a radio frequency wave transmission device according to the invention.

The transmission device 10 shown in Figure is a weapon designed to emit microwave, in a determined direction T-T, an electromagnetic field to disturb or destroy any device comprising electronics.

The device 10 includes a source of electromagnetic radiation in the radio frequency domain 12 formed by a tube, high power and a transmission antenna 14 connected to the source 12 by a waveguide 16.

The radiation source is high power, of several hundred megawatts, for example a magnetron, a MILO for " Magnetically Insulated Line Oscillator " in English, a relativistic carcinotron or a klystron.

The transmitter antenna 14 has a planar emitting surface 21, on which is distributed a set of antenna elements that provide a coherent field in the direction T-T by adding the elementary fields, in phase in the direction under consideration, different antenna elements.

In the exemplary embodiment, the transmitter antenna 14 is of revolution and has an axis of revolution X-X constituting a normal to the emitting surface 21. For example, the antenna is an antenna array radial transmission lines, or slotted type 'reflect array'.

Furthermore, the transmitting antenna 14 is capable of emitting T-T angularly offset in the direction of a fixed angle θ with respect to the axis of revolution X-X of the antenna 14. Preferably, the angle θ between the axis of revolution X-X T-T and the emission axis of the antenna 14 is substantially equal to 45°.

Each antenna element is formed of a radiating source fixed relative to the emitting surface 21. Depending on the type of array antenna retained, these sources are propellers or slots. The position and the geometry of the radiating sources are calculated so as to the law of illumination and the desired off-axis angle.

For example, the de-tracking of the antenna is formed according to the document US 6,259 415.

This that with such an arrangement, a coherent wave is produced by summing the elementary electromagnetic wave produced by each antenna element. The coherent wave propagates in the direction forming an angle θ T-T predefined with respect to the normal of the emitting surface 21. According to the invention, the guide conduit 16 includes a first 22 and a second 24 guides connected by a fixed angular aperture bend 26. The first and second waveguides 22, 24 are each straight and are designed to propagate the electromagnetic radiation of the source 12 to the antenna 14.

The first waveguide 22 is along the axis of revolution X-X of the antenna to which it is rigidly connected. Furthermore, the first waveguide is adapted to rotatable generally about the axis of revolution X-X by being driven by a first motor not shown.

The mode of propagation in the guide is magnetic transverse TM type₀ i. Such a mode is the natural product by power tubes such as the ml or the LO carcinotron. If the output mode contemplated of the tube is of a different nature, the antenna 14 comprises, facing the second waveguide 22 a metal cone adapted to change the propagating mode of the electromagnetic flux, to obtain a transverse mode type magnetic TM₀ i. The TM mode₀ i present in effect the advantage of an electric field and a magnetic field on the zero axial walls, providing swivel joint without concern of breakdown even at high power.

Furthermore, the second waveguide 24 is connected to the source of electromagnetic radiation. The second waveguide 24 extends along another axis Z-Z and is rotatable about the axis generally Z-Z by being driven by a second motor not shown. X-X The axis of the antenna and the other axis Z-Z are concurrent. In the exemplary embodiment, the axis is vertical Z-Z.

The transmission device comprises two rotary joints rotatable on the first and second waveguides. A first rotating joint 22A X-X is disposed along the axis, between two consecutive sections coaxial 22Β , 22C of the first waveguide.

Also, the second rotary joint 24A Z-Z is disposed along the axis, between two consecutive sections 24Β , 24C the second waveguide.

Each rotating joint is formed by two consecutive coaxial sections connected by a ball bearing.

The thus comprises that the antenna 14 is adapted to turn generally both about its axis of revolution and X-X Z-Z about the other axis.

Radio frequency The transmission device according to the invention is free from other joints forming angular degrees of freedom between the source 12 and the antenna 14 thereby reducing the risk of breakdown.

In operation, in such a discharge device, the electromagnetic flux is generated by the source of electromagnetic radiation. It is irradiated to the antenna 14 by the guide conduit 16 first Z-Z along the axis in the second waveguide 24 and then along the axis of revolution of the antenna X-X in the first waveguide 22. The electromagnetic wave is then emitted in the direction of transmission of the antenna T-T angularly offset an angle θ of the axis of revolution X-X of the antenna. In the case where the antenna 14 is fed on another embodiment that the TM mode₀ i, the mode converter changes the mode of propagation of the transmitted electromagnetic flux by feeding the antenna so as to obtain the TM mode₀ i.

The first waveguide 22 rotates generally around the axis of revolution X-X by operating the first motor.

Been that the direction of emission of the electromagnetic wave T-T described a cone the generatrix of which forms an angle θ with the axis of revolution X-X of the antenna by the rotation of the first waveguide.

Furthermore, the second waveguide 24 rotates generally around the other axis Z-Z by the operation of the second motor thereby rotatably the assembly formed by the first waveguide and the antenna.

Been that such an arrangement allows the transmission of electromagnetic wave on 360°de simple and efficient.

Furthermore, the volume of the displacement of the antenna, which is usually large to have a large gain, is strongly limited which is a great advantage for the airborne systems equipped with such a discharge device.