UA34434C2 - Transmission antenna system with the phased array - Google Patents

Abstract

The present invention relates to aerial assemblies for the microwave beams and, in particular, to phased array antennas generating several antenna beams simultaneously by control of the relative phase of signal multitude of radiating elements.

Description

The present invention relates to antenna systems for IED beams and, in particular, to phased antenna arrays that generate several antenna beams simultaneously by controlling the relative phase of the signals of multiple radiating elements.

Antenna arrays have been used for many years in radar systems to form narrow directional beams. The characteristics of the antenna array are determined by the geometric arrangement of the radiating elements, as well as the amplitude and phase of their individual excitation signals.

Later developments in the field of radars, such as the magnetron and other powerful microwave devices, extended the traditional operating range of radars towards high frequencies. At those higher frequencies, a simpler antenna, consisting of reflectors of certain shapes, found practical use! (parabolic and horn) or other simple irradiators.

Then, for many reasons, including the requirements for scanning speed and the ability of arbitrary or programmed beam guidance, electronless (inertial) scanning acquired special importance. With the development of phase shifters and commutators with electronic control, the attention of specialists turned to antenna arrays, in which each radiating element is individually controlled electronically. Controllable phase shifters provide the possibility of rapid and accurate switching of beams in the technique of antenna phasing arrays, and thus allow the radar to perform many functions that alternate in time, or even simultaneously. A radar with a phased antenna array with electronic control is capable of tracking multiple targets, irradiating several targets for guiding missiles at them, performing a search in a wide angular sector with automatic target selection to ensure tracking of the selected target, and can work as a communication system with by remote receivers and/or transmitters using beams that provide a high gain coefficient of the antenna system. Thus, the antenna array with phase scanning is very important. General information on modern antenna arrays can be found in "Vadag Napabrook" ru Meitia T. 5koipik. MSskhgam NIII (1970).

Famous antenna grid descriptions! also in the patents below.

US patent No. 2967301 dated January 1961 describes a method of forming successive beams for determining the speed of an aircraft relative to the ground.

US patent No. 3423756 dated January 21, 1969 describes a system in which an electronically controlled antenna with conical scanning is excited by means of an oversized waveguide and four tuned resonators located near and connected to it. The signal to the frequency of which the volume resonators are tuned is split into modes! higher orders of magnitude, which leads to a shift of the phase center of the radiation from the center of the apertures! antennas Conical scanning is achieved by sequential tuning of four resonators to the frequency of that signal. Signal! with frequencies significantly different from the frequency to which these resonators are tuned, propagate along the waveguide without distortion.

US patent No. 3,969,729, dated July 13, 1976, describes an integral element/phase shifter intended for use in gratings with phase scanning. Excitation of the lattice elements is carried out with the help of a number of strip transmission lines or non-resonant waveguides. Four RF diodes, connected and arranged in a certain way in the slots of the symmetrical slot structure in the outer conductive wall of the transmission line, serve to change the connection through the slots between the transmission line and the aperture of each individual element of the antennas. Thus, each diode regulates the contribution of each slit to the aperture energy! of a separate element at the corresponding phase and thus determines the overall phase of the specified aperture!

In the US patent Mo 4041501 dated August 9, 1977, descriptions! systems of antenna arrays, in which the working structure of elements is supplemented by communication circuits, so that! bring it as close as possible to the ideal structure of elements necessary for radiation within the selected angular sector of space. The use of communication circuits in the antenna design with beam scanning significantly reduces the number of required phase shifters.

US patent No. 4,099,181, dated July 4, 1978, describes a flat antenna for a radar, containing a set of radiating elements installed one after the other, arranged in parallel rows, in which the amount of energy between the specified radiating elements and the radar hardware can be adjusted. Emitting evil! are waveguides with coplanar radiating ends, grouped in four quadrants, each of the specified quadrants is connected to the hardware part of the radar through a feeder adapted to work in two modes: in the first mode, it asks the entire waveguide! in the quadrant, and in the second - only the antenna row closest to the center! waveguides, excluding other waveguides! quadrant There is also a device that simultaneously provides the same operating conditions to all four feeders, so that the radar antenna emits a beam that is symmetrical about the center of the antenna and has a different configuration depending on the mode of the feeders.

US patent No. 4595926 dated July 17, 1986 describes a system for forming a beam of a linear phased array antenna that can be used in monopulse transmitting and receiving stations, containing a pair of sequentially connected defocusing lenses with parallel plates that provide a suitable amplitude drop radiation distribution of a linear antenna array to suppress the side lobes of its diagrams! orientation Digital phase shifters are used to control the beam, and defocusing lenses are used to decorrelate discretization errors caused by the use of such phase shifters.

US patent No. 3,546,699 dated December 8, 1970 describes a scanning antenna system containing a stationary array of separate in-phase sources of electromagnetic energy, located along the arc of a circle, a converter installed near the array, which has the property of in-phase radiation of electromagnetic energy, with an arc-shaped input circuit corresponding to the grid arc, and a linear output circuit and a device for rotating the converter in the plane of a circle around its center.

In accordance with the invention, an antenna system with a phased array is proposed, in particular, an active transmitting phased antenna array that simultaneously generates several independent beams for irradiating specific areas of space without irradiating other areas. The size and shape of these areas are determined by the size and number of lattice elements, and the number of beams is determined by the number of beam formation schemes feeding the lattice. All element gratings work at the same level of amplitudes, and the direction and shape of the beams are determined by the phase settings.

The essence of the invention is explained by the drawings, on which:

Fig. 1 depicts a set of ordered elements of an active transmitting phased antenna array,

Fig. 2 schematically depicts a cross-section of a single element from a plurality of elements of the phased antenna array shown in fig. 1,

Fig. Z schematically depicts a top view of the air dielectric resonator shown in fig. 2,

Fig. 4 schematically depicts a bottom view of the controller used in the system of FIG. 2,

Fig. 5 schematically, but in more detail, depicts the phase shifters and the attenuator, shown in fig. 4, together with the related schemes.

According to fig. 1 shows a variant of an active transmitting phased antenna array, containing, for example, 213 elements arranged in the form of a hexagon. In fig. 2 shows one of the 213 elements of the antenna shown in fig. 1. Each element shown in fig. 1, is identical to the element shown in fig. 2, and includes a horn 10 capable of emitting a signal! each of two orthogonal polarizations with a separation of 25 dB or more. The horn is excited by a multi-pole bandpass filter 12, designed to pass de-energized signals with a frequency in a given band and not to pass de-energized signals of other frequencies. This is especially important when the transmitting antenna, filled according to the invention, is used in a communication satellite, which also contains a receiving antenna (receiving antenna), since otherwise a parasitic signal occurs! the sensitivity of the transmitter in the reception band is overloaded! receiving antennas and create interference. In the present embodiment of the invention, the filter 12 contains a series of volume resonators connected in series, connected to each other in such a way as to provide a high degree of orthogonality necessary to provide the above decoupling.

The filter 12 is connected to the air dielectric resonator 14, installed on the substrate 36.

Air dielectric resonator 14 contains integrated amplifiers with high efficiency, exciting orthogonal IED signal! when turned on according to the two-stroke circuit. According to fig. 3, which shows a schematic top view of the air dielectric resonator 14 shown in fig. 2, that is, excitation is carried out with the help of pins 18, 20, 30 and 32 in combination with amplifiers 22, 24, 26 and 28.

In fig. 3 poles 18 and 20 are positioned so that they excite the resonator 14 when one is positioned relative to the other at an angle of 1802. Such an arrangement provides the transformation necessary for work! two-stroke circuit, when amplifiers 22 and 24 are started with a phase shift. Similarly, amplifiers 26 and 28 excite pins 30 and 32, arranged at an angle of 1802 relative to each other and at an angle of 909 relative to pins 18 and 20, and thus can excite an orthogonal microwave signal! in the resonator. Two pairs of amplifiers are excited with a phase shift of 902 from the hybrid input 34 through the 180-degree element 34a and 3456 connections, so that! receive a signal with circular polarization.

Amplifiers 22, 24, 26 and 28 must! be almost identical to ensure the phase and amplitude uniformity necessary for orthogonal beams. The only practical way to achieve this goal is to use monolithic ICs as amplifiers.

In fig. It is shown that the 90-degree hybrid input 34 has two outputs. Get out! are connecting elements passing through the substrate 36, shown in the bottom view in fig. 4, but the lower contact! of those connecting elements of designation! numbers 38 and 39. One of those outputs triggers a signal! with right circular polarization, and the other with left circular polarization.

In addition, if you hit the signal! excitations passing through the connecting element were fed directly to the 180-degree element! 34A and 34B connections, without using the 90-degree hybrid input 34, then linearly polarized rays were excited, and not rays with circular polarization. Signal! the hybrid input 34 is received through a contact! 38 and 39 are the pre-final amplifiers on 40 and 42, which are implemented on monolithic integrated circuits of the IED and each of which is intended for signals of a certain polarization. The required polarization for each beam is selected with the help of the switching matrix 44, which also combines all the signals! for each polarization, which are then applied to the inputs! pre-final amplifiers 40 and 42. At the input of the channel of each beam (in this example, there are four of them) there is a phase shifter 48 and an attenuator 46 with electronic control, which determine the direction and shape of the beam (the size of each beam). For each specific beam, everything is wrong! gratings are excited by signals of the same level. This is the difference from other transmitting phased antenna arrays, in which a signal is used to suppress the side lobes! with an amplitude gradient transverse to the lattice!.

In order to maximize efficiency antennas in terms of power, in the active transmitting phased antenna array described in this application, homogeneous excitation (without gradient) is used. Otherwise, the power of each element of the antenna is not fully used. The total maximum possible power can be distributed arbitrarily and without losses between the beams.

After distributing the power for this beam across all elements of the antenna, by adjusting the attenuators 46, the phases are set! (which, most likely, is different for each element) with the help of phase shifters 48 to give the required direction and shape to the rays. Phase settings! for the ray of a given form and direction vibrate in the process of ego synthesis. The synthesis process is an iterative computational procedure that can be stored in the computer's memory. The task of the synthesis process is the formation of a beam that provides effective radiation in a given area of space without radiation in other areas. This region of space has the shape of a regular polygon, the minimum size of the sides! which is determined by the selected number of lattice elements and the distance between them. In general, the more elements in the lattice, the more complex the shape of the polygon that can be synthesized. In the process of beam formation only with the help of phases! not only the given shape of the beam is created, but also the side lobe. The second task of this invention when used as a satellite antenna is to minimize the relative size! lateral petals and preventing their appearance on the surface of the earth, if viewed from the side of the orbit! satellite, so that they do not interfere with the neighboring beam and do not lead to a loss of energy for radiation in an unnecessary direction. In the process of synthesis, the level of side lobes is minimized, and zero diagrams can also be formed! directivity at the location of the side lobe, which cannot beat, is minimized to an acceptable level by the second method.

The number of independent beams, which can be formed by an active transmitting phased array antenna, is limited only by the number of phase shifters 48 and attenuators 46 asking each element. According to fig. 5, the signal for each chain of phase shifters 48 and attenuators 46 comes through a separate uniform power divider. The number of taps of each power divider must be greater than or equal to the number of elements. In the example shown in fig. 5, the number of taps should be greater than or equal to 213. The number of power dividers should be equal to the number of individual beams generated by the antenna. Thus, for the system described as an example! four power dividers are required, each of which has 213 taps.

As previously stated, in order to obtain the maximum efficiency it is necessary that the power of each of the beams is equal to the sum of the powers of all elements. It is assumed that the power of each individual element is linear or undistorted. In order to! several beams generated by an active transmitting phased array antenna do not interact with each other, it is necessary that all amplifiers in the circuit work in a linear mode, which prevents unwanted cross-interference between the beams. As long as the amplifiers work in the linear mode, the principle of linear superposition is valid. The independence of the beams is violated as soon as the amplifiers start working in a non-linear mode. Finally, amplifiers 22, 24, 26 and 28 are the most critical, as they consume more than 9095 power.

In order to ensure acceptable working characteristics, they must! have a harmonic coefficient of the order of 0.195 at all operating signal levels below the calculated maximum.

Each element is controlled by the microprocessor controller 50 shown in Fig. 5, and interface electronics located in the body of the matrix BIS. The controller 50 can not only generate special control voltages for controlling each phase shifter and attenuator, but also stores in memory the set of current and subsequent commands. With the help of this beam control mechanism, it is possible to switch either according to the requirements, or in the mode of time compression to serve a large number of independent areas of space. Controllers of all elements are connected to each other with the help of typical inter-block control buses. When the antenna is used in a communication satellite, the interblock control bus is also used to connect to the main controller located together with the electronic control circuits of the satellite. A characteristic set of coefficients for each beam is randomly calculated on the ground and transmitted to the satellite via the control line. Each element has its own address, which is determined by the "locked" code on the unifying circuit to which the hardware part of the element is connected. A thermistor can be used to compensate for the temperature drift of the voltage controllers, if required. If the voltages used to control the phase and amplitude are non-linear, then microprocessors can store tables of transformation coefficients for their linearization.

Although the invention was described in detail in relation to the preferred version of its implementation, it should be clear to specialists that it is possible! various changes without deviating from the scope and essence of the invention.

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Ukraine, 88000, Uzhgorod, st. Gagarina, 101 (03122) 3-72 -89 (03122)2-57- 03