EP0241380B1 - Verfahren und Vorrichtung zur Strahlfokussierung von Gruppenantennen auf einen Prüfpunkt - Google Patents

Verfahren und Vorrichtung zur Strahlfokussierung von Gruppenantennen auf einen Prüfpunkt Download PDF

Info

Publication number
EP0241380B1
EP0241380B1 EP87400803A EP87400803A EP0241380B1 EP 0241380 B1 EP0241380 B1 EP 0241380B1 EP 87400803 A EP87400803 A EP 87400803A EP 87400803 A EP87400803 A EP 87400803A EP 0241380 B1 EP0241380 B1 EP 0241380B1
Authority
EP
European Patent Office
Prior art keywords
signal
microwave
signals
radiation
modulation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP87400803A
Other languages
English (en)
French (fr)
Other versions
EP0241380A1 (de
Inventor
Jean-Charles Bolomey
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Centre National de la Recherche Scientifique CNRS
Original Assignee
Centre National de la Recherche Scientifique CNRS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Centre National de la Recherche Scientifique CNRS filed Critical Centre National de la Recherche Scientifique CNRS
Publication of EP0241380A1 publication Critical patent/EP0241380A1/de
Application granted granted Critical
Publication of EP0241380B1 publication Critical patent/EP0241380B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q21/00—Antenna arrays or systems
    • H01Q21/06—Arrays of individually energised antenna units similarly polarised and spaced apart
    • H01Q21/22—Antenna units of the array energised non-uniformly in amplitude or phase, e.g. tapered array or binomial array
    • H01Q21/225—Finite focus antenna arrays
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/18—Methods or devices for transmitting, conducting or directing sound
    • G10K11/26—Sound-focusing or directing, e.g. scanning
    • G10K11/34—Sound-focusing or directing, e.g. scanning using electrical steering of transducer arrays, e.g. beam steering
    • G10K11/341—Circuits therefor
    • G10K11/346—Circuits therefor using phase variation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
    • H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
    • H01Q3/2605—Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays

Definitions

  • the present invention firstly relates to a method of focusing, on at least one point to be examined from a radiation source, the antennas of an array of antennas receiving the radiation from the point with corresponding respective reception phase shifts at the time of travel of said radiation between said point and the respective antennas.
  • Such a method is used when it is desired to obtain, from the microwave radiation coming from an object to be analyzed, a microwave image of this object.
  • a set of antennas is organized to form a network, this term being taken in a similar, but broader, sense than that which it possesses in optics, and this network of antennas is successively focused on each of the points to examine of the object, so as to build, point by point, the microwave image of this object.
  • Microwave imaging systems have, in particular, applications in biomedical engineering for the detection and treatment of tumors, for example, as well as in civil engineering, for the detection of buried objects for example, or for control of materials treated by microwave radiation (polymerization, thawing, drying ).
  • the antennas known by the name of electronically scanned antennas are organized in a fixed array of antennas which has maximum sensitivity in a variable direction electronically controllable, and implements such a process, corresponding to focusing on a point located at an infinite distance, and defined only by its direction.
  • a focusing method is already known in the microwave radiation field, in which the signal received by each antenna is phase-shifted in a microwave phase shifter, the phase-shifted signals are added and the summation signal subjected to microwave detection.
  • the phase law which determines the particular phase shift to be applied to each received signal, is established so that the contributions from the point on which the network is focused are in phase at the time of summation, the contributions from other points having any phases with respect to each other.
  • the signal obtained mainly represents the contribution of the focal point.
  • This known method has, on the one hand, the disadvantage of a difficult implementation from a practical point of view, because it requires the use of as many microwave phase shifters as there are antennas in the array.
  • a microwave phase shifter is a relatively complex component, with a high cost price and a large size. In cases where the number of antennas reaches several hundred, even several thousand, this solution is therefore very expensive.
  • the size of the phase shifters conditions the distance between an antenna and the neighboring antennas, that is to say the pitch of the network.
  • a not-too-large antenna will give a poor quality image.
  • a drawback of this method is that it does not allow simultaneous focusing on several points.
  • each received signal is not phase-shifted, which is subjected directly to coherent microwave detection, that is to say a detection making it possible to know the signal detected in module and in phase.
  • Module and phase of each signal received are then acquired by a computer.
  • the computer performs digital processing of all of this data, in order to extract the contribution from any point of the object.
  • Such processing therefore amounts to synthetic focusing as opposed to analog focusing obtained using microwave phase shifters.
  • the modulated signals are each delayed by a specific delay before undergoing an addition. This therefore implies the use of as many delay circuits as there are antennas in the network and complicates the law followed by the modulation phase shifts.
  • the applicant has sought a focusing method of analog type, which can adapt to any geometry of the network, but does not require the use of a large number of elementary circuits, such as the microwave phase shifters of the known microwave process or the delay circuits of the known acoustic process.
  • the method of the invention does not use any microwave phase shifter. This is the low modulation signal frequency which is out of phase in low frequency phase shifters, moreover very simple. This result is obtained by modulating in amplitude the signals delivered by antennas. However, as will be discussed below, it is possible to use space-saving and inexpensive microwave modulators.
  • the method of the invention being an analog type method, it can adapt to unconventional network geometries, it makes it possible to compensate for irregularities in the alignment of the antennas of the network, for example, it has a better signal ratio noise than the synthetic focusing process, and it can adapt to incoherent radiation.
  • the signals delivered by the antennas are amplitude modulated by a low frequency modulation signal of the square type, with modulation phase shifts.
  • the modulation can be carried out using microwave switches, of the PIN diode type for example, therefore with a low cost and size.
  • the invention can also be implemented for focusing the antennas of an array of transmit antennas.
  • a focusing device 30 is provided with J inputs receiving the J signals s l , ..., s j , ..., and s J. It is also provided with two outputs delivering two useful signals U X and V X , as well as a control input receiving, here by means of a parallel bus, a control signal ⁇ X.
  • the object 20 may itself be the source of radiation received by the antennas 1, or it may act as a secondary source, that is to say as a reflector of radiation emitted by a primary microwave source, intended to illuminate object 20, and not shown in FIG. 1 for the sake of simplicity.
  • the microwave radiation received by the antennas l is monochromatic of frequency f , either because the radiation source is itself monochromatic of frequency f , or because, the source emitting a radiation in a certain frequency band, a selective focusing device 30 is used, centered on the frequency f .
  • the series of J antennas 1 arranged regularly in the plane P is called, by analogy with the networks encountered in optics, antenna array.
  • the microwave image is obtained by successively focusing the array of antennas l on each of the points to be examined X of the object 20, during a sequential scanning, point by point, of this object.
  • focusing the antennas l of the antenna array on a point X is meant control of the focusing device 30 using the control signal ⁇ X so that the useful signals U X and V X at the output of the device are only representative of microwave radiation from point X.
  • a sequential scanning device not shown, generates the successive control signals ⁇ X and a display device, not shown, synchronized by the sequential scanning device, collects the signals U X and V X.
  • the sequential scanning device and the viewing device are of the conventional type used in known imaging systems.
  • each signal s j is subjected to a microwave phase shift of a determined angle ⁇ X (j), and the J signals are phase-shifted.
  • the law ⁇ X (j) which determines the phase shift angle for each signal s j called the phase law for point X, is established so that the contributions coming from point X, finding themselves in phase at the time of the summation, interfere constructively, while the contributions coming from the other points, having any phases with respect to each other, interfere destructively.
  • the result of the summation mainly represents the contribution of point X.
  • We therefore focus the array of antennas l on point X by imposing the phase law ⁇ X (j) using the signal ⁇ X.
  • the phase law ⁇ X (j) can be deduced from knowing the lengths of the paths connecting point X to each of the antennas l.
  • each reference 2 designates a microwave switch. There are as many switches 2 as there are inputs, that is to say here J switches.
  • the switch 2 of row j is provided with a microwave input receiving the signal s j and a microwave output delivering the signal s ′ j , as well as a control input receiving a signal C j .
  • a microwave summing device 3 is provided with J inputs receiving the J signals s ′ l , ..., s ′ j , ... and s ′ J , and an output delivering a signal s .
  • a coherent microwave detection circuit 6 is provided a signal input receiving the signal s , a control input and two outputs delivering DA and DB signals.
  • a microwave oscillator 4 is provided with an output delivering a signal r of coherent microwave detection, connected to the control input of circuit 6.
  • the signal r is a sinusoidal signal of frequency f .
  • a low frequency coherent detection circuit 8 is provided with two signal inputs receiving the signals DA and DB, a control input and two outputs delivering the signals U X and V X.
  • a low frequency oscillator ll is provided with an output delivering a modulation signal D, connected to the control input of circuit 8.
  • the signal D is a sinusoidal signal of frequency F, of value between substantially a few kilohertz and substantially a few megahertz.
  • a phase shift circuit l2 is provided with an input receiving the signal D, J commando inputs connected to the parallel duo receiving the control signal ⁇ X , and J outputs delivering the J signals C l , ..., C j , ... and C J.
  • the microwave coherent detection circuit 6 comprises two mixers 6l and 62 and a phase shifter 63.
  • the mixers 6l and 62 are of the type comprising two inputs, and one output delivering a signal equal, at all times, to the produces signals received on both inputs. These are devices known to those skilled in the art as ring modulators or balanced mixers.
  • the mixer 6l receives on an input the signal s and on the other input signals r , and outputs DA signal.
  • the mixer 62 receives on one input the signal s and on the other input the signal r phase shifted by an angle equal to ⁇ / 2, in the phase shifter 63.
  • the mixer 62 outputs the signal DB.
  • the low frequency coherent detection circuit 8 includes four mixers 8l, 82, 83 and 84, two phase shifters 85 and 85 ′, a subtractor 86 and an adder 88, and two low-pass filters 87 and 89 .
  • the mixers 8l to 84 are of a type comparable to that of the mixers 6l and 62.
  • the mixer 8l receives on one input the signal DA and on the other input the signal D, and it outputs a signal SA.
  • the mixer 82 receives on one input the signal DB and on the other input the signal D phase shifted by an angle equal to ⁇ / 2 in the phase shifter 85, and it outputs the signal SB.
  • the mixer 83 receives on one input the signal DA and on the other between the signal D phase shifted by an angle equal to ⁇ / 2 in the phase shifter 85 ′, and it outputs the signal SC.
  • the mixer 84 receives the signal DB on one input and the signal D on the other input, and outputs the signal SD.
  • the subtractor 86 receives on its two inputs the signals SA and SB; its output is connected to filter 87, which outputs the signal U X.
  • the adder 88 receives on its two inputs the signals SC and SD; its output is connected to filter 89 which outputs the signal V X.
  • the phase shift circuit l2 includes J controllable phase shifters l2l.
  • the phase shifter l2l of rank j is provided with a signal input receiving the signal D, with a control input for the angle ⁇ X (j) of phase shift, receiving a control signal also called ⁇ X (j) in for the sake of simplicity, and of a signal output delivering the signal C j , phase shifted by the angle ⁇ X (j) relative to the modulation signal D.
  • the J control inputs of the J phase shifters l2l constitute the parallel bus to which is applied the signal ⁇ X composed of the J signals ⁇ X (j).
  • the switches 2 are here PIN diode switches, well known to those skilled in the art.
  • the adder 3 and the mixers 6l and 62 are circuits of the type known by a person skilled in the art for microwave use, while the mixers 8l to 84, the subtractor 86 and the adder 88, the low-pass filters 87 and 89 and phase shifters 12l are circuits of the type known to those skilled in the art for use at low frequency.
  • the signal s ′ j is amplitude modulated by a square type modulation signal, as shown in Figure l0.
  • the first component of this signal is here filtered by the mixer 6l. If this were not the case, a low pass filter would eliminate this component.
  • DA j A j / 2. cos ⁇ j . Ech [C j ]
  • Ech [C j ] can be broken down into a fundamental: l ⁇ cos (2 ⁇ Ft + ⁇ X (j)) and harmonics.
  • U Xj A j / 4 ⁇ [cos ⁇ j . cos ( ⁇ X (j)) - sin ⁇ j . sin ( ⁇ X (j))]
  • V Xj A j / 4 ⁇ . sin [ ⁇ j + ⁇ X (j)]
  • phase shift ⁇ X (j) of the modulation signal is added to the phase shift ⁇ j of the microwave signal. So everything happens as if the signal s j was phase shifted by an angle ⁇ X (j) in a microwave phase shifter.
  • the signals U X and V X equal to the sum of all U Xj and V Xj respectively, are well representative of the radiation emitted by the focusing point X.
  • the focusing device 70 shown in Figure 6 allows the simultaneous focusing on two points X and Y of the object 20, to continuously observe what is happening at these two particular points without having to form a complete image, for example to follow the evolution of their temperature in the case of certain biomedical applications.
  • the focusing device 70 is provided with two buses receiving the signals ⁇ X and ⁇ Y representative phase laws ⁇ X (j) and ⁇ Y (j) corresponding to the points X and Y to be observed.
  • the focusing device 70 is also provided with two groups of two outputs continuously supplying signals representative of the points X and Y, here for example the previously defined signals U X , V X , U Y and V Y.
  • the focusing device 70 differs from the device 30 of FIG. 2 essentially in that it comprises two oscillators 7ll and 7ll ′ delivering two signals D l and D2 respectively, of frequency F l and F2 respectively.
  • the two signals D l and D2 are of the same type as the signal D already encountered.
  • the output signal from the oscillator 7ll is applied to a phase shift circuit 7l2 analogous to the circuit l2 in FIG. 2.
  • the circuit 7l2 is controlled by the signal ⁇ X.
  • the output signal from the oscillator 7ll ′ is applied to a phase shift circuit 7l2 ′ analogous to the circuit l2 in FIG. 2, controlled by the signal ⁇ Y.
  • Each circuit 7l2 and 7l2 ′ delivers a set of J modulation signals analogous to the signals C l , ..., C j ..., and C J of FIG. 2.
  • the two modulation signals of rank j control two switches 72 mounted in parallel downstream of an antenna 7l, of row j .
  • the switches 72, 2J in number, and the antennas 71, the number of J, are similar to the switches 2 and the antennas 1 in FIG. 2.
  • the J output signals of the J groups of the two switches 72 in parallel are added in a microwave summator 73, which delivers a signal s .
  • a coherent microwave detection circuit 76 analogous to circuit 6 in FIG. 3, receives the signal s on its signal input and deliberates two signals DA and DB on its two outputs.
  • a microwave oscillator 74 analogous to oscillator 4 of FIG. 2, delivers a signal r to the control input of circuit 76.
  • Two low frequency coherent detection circuits 78 and 78 ′ are provided, analogous to circuit 8 in FIG. 4. Each circuit 78 and 78 ′ receives the signals DA and DB on its two signal inputs, and, on its control input the signal D l and signal D2 respectively. Circuit 78 outputs the signals U X and V X , and circuit 78 ′ signals U Y and V Y.
  • the operation of the focusing device 70 is as follows. Because the frequencies F l and F2 of the signals D l and D2 are different, the low frequency coherent detection circuit 78 demodulates only the components of the signals DA and DB modulated at the frequency F l in the switches 72, that is ie those which correspond to the phase shift law ⁇ X , determined by the phase shift circuit 7l2, focusing the network on the point X. For the same reason, the circuit 78 ′ demodulates only the components of the signals DA and DB modulated at the frequency F2, that is to say those which correspond to the phase shift law ⁇ Y , focusing the grating on the point Y.
  • the focusing method of the invention can be extended to imaging systems in which a focused antenna array is used to illuminate a point of the object to be observed and an unfocused antenna array, or even a single omnidirectional antenna, to receive radiation from the illuminated point.
  • FIG. 7 represents a device implementing such a method.
  • Block 50 represents the focusing device of a network of K transmitting antennas 5l to focus on the point X ′ of the object 20 ′.
  • the focusing device 50 comprises a microwave oscillator 54, delivering a microwave emission signal e , of frequency f .
  • Each antenna 5l is connected to the output of the oscillator 54 by means of a microwave switch 52, of the same type as the switches 2 in FIG. 2.
  • the switch 52 of rank k is provided with an input of command receiving a signal C k .
  • a phase shift circuit 5l2 analogous to the phase shift circuit l2 in FIG. 5, is provided with a signal input and with K outputs delivering the signals C l , ..., C k , ..., and C K each signal C k being out of phase with respect to the signal received on the input of circuit 5l2 by an angle ⁇ X (k) controlled by the signal ⁇ X applied to the control bus of block 5l2.
  • An oscillator 511 analogous to the oscillator ll of FIG. 2, delivers a signal D ′ of frequency modulation F, at the input of the block 5l2.
  • a reception antenna 40 On reception, a reception antenna 40, here unique, receives the signals coming from the object 20 ′. It is followed by a coherent microwave detection circuit 56, analogous to circuit 6 in FIG. 3. Circuit 56 receives, on its control input, the output signal from oscillator 54. The two outputs of circuit 56 are connected to a coherent detection circuit 58, analogous to circuit 8 in FIG. 4. The control input of circuit 58 receives the modulation signal D′. Circuit 58 outputs the signals U X and V X.
  • the operation of the focusing device 50 is similar to that of the device 30.
  • the phase shifts ⁇ X (k) introduced on the modulation signals of the microwave signals emitted produce the same effect, on the signal received and subjected to coherent microwave microwave detection. f , in circuit 56, and at coherent low frequency detection at frequency F in circuit 58, that phase shifts ⁇ X (k) introduced on the microwave signals transmitted. If these phase shifts ⁇ X (k) are chosen to correspond to the phasing, at point X, of the signals coming from the K antennas 5l, the transmission network has therefore been focused on point X.
  • linear networks are used instead of planar networks, the direction of the transmission network being perpendicular, for example, to the direction of the reception network.
  • crossed linear arrays are well known to those skilled in the art for their better longitudinal spatial resolution and the reduced number of antennas used.
  • each antenna was a microwave signal guided by a guide structure of the waveguide, cable type. coaxial or ribbon line, for example.
  • the summation is carried out by a microwave summing device, like the summing device 3 of FIG. 2, provided with J inlet access and an outlet access, each access being connectable to a guide structure of the type defined here. -above.
  • FIG. 8 shows for example a device in which the receiving antennas are dipole antennas l ′, regularly arranged on a panel l00 made of insulating material.
  • the panel l00 is placed in front of a single antenna 4l, which plays the role of summing of the microwave signals picked up and radiated again by the antennas l ′, these signals no longer being, as previously, supported by a guide structure.
  • the switches may be simple diodes 2 ′, the switching signals C l , ..., C j , ... and C J being for example applied by means of connections 2l which are not very disturbing for the electromagnetic field.
  • connections are made, for example, of carbon wires so as to be sufficiently resistive to have only a slight influence on the electromagnetic field.
  • connections 2l can also consider, to remove the connections 2l, to use diodes 2 'photoconductive switched using light signals applied for example using a laser beam.
  • the antenna 4l playing the role of summing device, is directly connected to a coherent microwave detection circuit, identical to the circuit 6 in FIG. 2, in the case of a network of reception antennas. The rest of the device is unchanged.
  • the focusing device 90 of FIG. 9 represents a variant of the device of the invention, using only two mixers instead of six.
  • a mixer 96l identical to the mixer 6l in FIG. 3, is provided with a first input receiving the signal s at the output of the summator 3, with a second input and with an output.
  • a mixer 98l identical to the mixer 8l in Figure 4, is provided with a first input connected to the output of the mixer 96l, a second input and an output connected to the input of a low-pass filter 987, identical to the low-pass filter 87 of FIG. 4 .
  • the output of an oscillator 94 is connected to the second input of the mixer 96l via a controllable phase shifter 963.
  • the output of an oscillator 9ll is connected to the second input of the mixer 981 via a controllable phase shifter 985.
  • the controllable phase shifters 963 and 985 are likely to phase shift by an angle equal to 0, or equal to ⁇ / 2, as a function of a signal applied to the control input with which each of them is provided.
  • a processing and control circuit 9l for example with a microprocessor, and provided with two outputs connected to the control inputs of the phase shifters 963 and 985, an input connected to the output of the low-pass filter 987, and two outputs delivering the signals U X and V X.
  • the operation of the focusing device 90 is as follows: the processing and control circuit 9l controls the phase shifters 963 and 985 sequentially, so that the previously defined signals SA, SB, SC and SD appear the year after the other at the input of the filter 987.
  • the circuit 9l stores the various filtered signals and processes the corresponding data to add them and deliver the signals U X and V X previously defined.
  • the signals picked up are coherent signals, that is to say periodic signals of defined phase, to which coherent microwave detection can be applied, as in circuits 6, 76, 6 ′ and 96l-63, as the case may be.
  • the invention is not limited to such coherent radiation and can also be applied to thermography, for example.
  • an image representative of the temperatures of the various points of the object is constructed, from microwave signals of which the object is itself the source.
  • These signals being inconsistent, that is to say of random phase, they must be detected with particular detection devices of known type, for example quadratic detection devices with or without prior frequency changes.
  • the devices of FIGS. 2, 6, 8 and 9 must therefore be modified, in this case, so that the coherent microwave detection circuits 6, 76, 6 ′ and 96l-963 are replaced by suitable devices.
  • the device 70 for simultaneous focusing on several points of FIG. 6 could then be modified by placing only one modulator downstream of each antenna, and by controlling this modulator with the sum of the two corresponding signals coming from the phase shift circuits 7l2 and 7l2 ′.
  • the antennas are generally organized on a surface to form an array.
  • the antennas can be organized in a line, straight or curved, to form a linear network.
  • a single switch can be used controlled by a suitable signal, for example the signal resulting from the product of the step functions relating to each of the phase shifted modulation signals.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Variable-Direction Aerials And Aerial Arrays (AREA)
  • Radar Systems Or Details Thereof (AREA)

Claims (11)

1. Verfahren zur Fokussierung von Antennen (1;71;1′) einer Gruppenantenne auf mindestens einen Prüfpunkt (X) einer Strahlungsquelle (20), wobei die Antennen die Strahlung des Punktes mit den jeweiligen Empfangsverschiebungen (δj) empfangen, welche der Wegzeit der genannten Strahlung zwischen dem genannten Punkt (X) und den jeweiligen Antennen entsprechen, und bei welchem die von den Antennen abgegebenen Signale (sj) durch mindestens ein gleiches Niederfrequenzmodulationssignal (D) mit den Empfangsverschiebungen entsprechenden Modulationsverschiebungen(Δx(j)) amplitudenmoduliert werden, dadurch gekennzeichnet, daß:
- die genannte Strahlung eine Mikrowellenstrahlung ist,
- jede Modulationsverschiebung (Δx(j )) jeder Empfangsverschiebung (δj) entspricht, damit ihre Summe (δj + Δx(j)) gleich bleibt, gleichgültig von welcher Antenne das Signal (sj) abgegeben wird,
- die modulierten Signale (s′j) zu einem Summensignal (s) summiert werden,
- die Mikrowellenkomponente des Summensignals (s) erfaßt wird und
- das erfaßte Signal (DA, DB) durch synchrone Demodulation demoduliert wird.
2. Verfahren gemäß Anspruch 1, bei welchem die von den Antennen abgegebenen Signale (sj) durch ein rechteckiges Niederfrequenzmodulationssignal mit Modulationsverschiebungen (Δx (j)) amplitudenmoduliert werden.
3. Verfahren gemäß einem der Ansprüche 1 und 2, bei welchem das erfaßte Signal (DA, DB) einerseits durch das Modulationssignäl (D) und andererseits durch das um π/2 verschobene Modulationssignal (D), dann durch Tiefpaßfiltrierung demoduliert wird.
4. Verfahren gemäß einem der Ansprüche 1 bis 3, bei welchem die Mikrowellenkomponente des Summensignals (s) einerseits durch ein Mikrowellendetektionssignal (r), andererseits durch dieses um π/2 verschobene Mikrowellendetektionssignal (r), dann durch Tiefpaßfiltrierung erfaßt wird.
5. Fokussierungsvorrichtung zur Durchführung des Verfahrens gemäß Anspruch 1 zur Fokussierung von Antennen (1;71;1′) einer Gruppenantenne auf mindestens einen Prüfpunkt (X) einer Strahlungsquelle (20), wobei die Antennen die Strahlung des Punktes mit den jeweiligen Empfangsverschiebungen (δj) empfangen, welche der Wegzeit der genannten Strahlung zwischen dem genannten Punkt (X) und den jeweiligen, Signale (sj) abgebenden Antennen entsprechen, dadurch gekennzeichnet, daß die genannte Strahlung eine Mikrowellenstrahlung ist, und vorgesehen sind:
- Vorrichtungen (11;711;711′;911) zur Erzeugung eines Niederfrequenzsignals (D;D1;D2),
- Vorrichtungen (12;712;712′) zur Verschiebung des Niederfrequenzsignals (D;D1;D2) um den Empfangsverschiebungen (δj) entsprechende Modulationsverschiebungen (Δx(j)), wobei jede Modulationsverschiebung (Δx(j)) jeder Empfangsverschiebung (δj) entspricht, damit ihre Summe (δj + Δx (j)) gleich bleibt, gleichgültig von welcher Antenne das Signal (sj) abgegeben wurde.
- Vorrichtungen (2;72;2′), um die von den Antennen abgegebenen Signale (sj) durch das Niederfreqüenzsignal (D;D1,D2) mit den Modulationsverschiebungen (Δx (j)) amplitudenzumodulieren,
- Vorrichtungen (3;73;41), um die modulierten Signale (s′j) zu summieren und ein Summensignal (s) abzugeben,
- Vorrichtungen (4,6;74;76;94,963,961,6′), um die Mikrowellenkomponente des Summensignals (s) zu erfassen und
- Vorrichtungen (8;78,78′;985,981), um das erfaßte Signal durch synchrone Demodulation zu demodulieren.
6. Vorrichtung gemäß Anspruch 5, bei welcher die Vorrichtungen zum Amplitudenmodulieren der von den Antennen abgegebenen Signale (sj) Mikrowellenschalter (2;72;2′) umfassen.
7. Vorrichtung gemäß einem der Ansprüche 5 und 6, bei welcher die Vorrichtungen (8;78,78′;985,981) zum Demodulieren des erfaßten Signals umfassen:
- Vorrichtungen (85,85′,985), um das Niederfrequenzsignal (D;D1;D2) um einen Winkel gleich π/2 zu verschieben,
- Vorrichtungen (81-84;981), um das erfaßte Signal einerseits durch das Modulationssignal (D;D1,D2) und andererseits durch das verschobene Modulationssignal zu vervielfachen,
- und Vorrichtungen (87,89;987), um die Niederfrequenzkomponenten des vervielfachten erfaßten Signals zu filtern.
8. Vorrichtung gemäß einem der Ansprüche 5 bis 7, bei welcher die Vorrichtungen (4,6;74,76;94,963,961,6′) zum Erfassen der Mikrowellenkomponente des Summensignals (s) umfassen:
- Vorrichtungen (4,74,94) zur Erzeugung eines Mikrowellendetektionssignales (r),
- Vorrichtungen (63;963), um das Mikrowellendetektionssignal (r) um einen Winkel gleich π/2 zu verschieben,
- Vorrichtungen (61,62;961), um das Summensignal (s) einerseits durch das Mikrowellendetektionssignal (r) und andererseits durch das verschobene Mikrowellendetektionssignal zu vervielfachen und um die Niederfrequenzkomponenten des vervielfachten Summensignals zu filtern.
9. Verfahren zur Fokussierung von Antennen (51) einer ersten Gruppenantenne auf mindestens einen Prüfpunkt (X′) eines von einer Mikrowellenstrahlung beleuchteten Gegenstandes (20′), wobei die Antennen die Strahlung in Richtung Punkt mit den jeweiligen Emissionsverschiebungen aussenden, die der Wegzeit der genannten Strahlung zwischen den jeweiligen Antennen und dem genannten Punkt (X′) entsprechen, wobei mindestens eine Antenne (40) die Strahlung des Punktes (X′) empfängt, dadurch gekennzeichnet, daß:
- die an den Antennen abgegebenen Signale von einem gleichen Mikrowellenemissionssignal (e) kommen, das durch mindestens ein erstes gleiches Niederfrequenzmodulationssignal (D′) mit den Emissionsverschiebungen entsprechenden Modulationsverschiebungen (Δx (k)) amplitudenmoduliert wurde, damit ihre Summe, unabhängig von der Antenne, gleich bleibt,
- die Mikrowellenkomponente des empfangenen Signals erfaßt wird und
- das erfaßte Signal durch synchrone Demodulation demoduliert wird.
10. Verfahren gemäß Anspruch 9, bei welchem mehrere Antennen zum Empfang der Strahlung des Punktes (X′) vorgesehen sind und eine zweite Gruppe bilden, wobei jede Antenne die Strahlung des Punktes mit den jeweiligen Empfangsverschiebungen empfängt, wobei:
- die von den Empfangsantennen abgegebenen Signale durch mindestens ein zweites gleiches Niederfrequenzmodulationssignal mit der Empfangsverschiebung entsprechenden Modulationsverschiebungen amplitudenmoduliert werden, wobei jede Modulationsverschiebung (Δx (j)) jeder Empfangsverschiebung (δj) entspricht, damit ihre Summe (δ j + Δx (j)) gleich bleibt, gleichgültig von welcher Antenne das Signal (sj) abgegeben wurde,
- die empfangenen modulierten Signale vor Erfassung der Mikrowellenkomponente des empfangenen Signals zu einem Summensignal summiert werden.
11. Verfahren gemäß Anspruch 10, bei welchem das erfaßte Signal durch mindestens ein Signal bei Uberlagerungsfrequenz ( FE - FR) zwischen der Frequenz (FE) des ersten Niederfrequenzmodulationssignals und der Frequenz (FR) des zweiten Niederfrequenzmodulationssignals demoduliert wird.
EP87400803A 1986-04-11 1987-04-09 Verfahren und Vorrichtung zur Strahlfokussierung von Gruppenantennen auf einen Prüfpunkt Expired - Lifetime EP0241380B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8605205 1986-04-11
FR8605205A FR2597268B1 (fr) 1986-04-11 1986-04-11 Procede et dispositif de focalisation, sur un point a examiner, des antennes d'un reseau

Publications (2)

Publication Number Publication Date
EP0241380A1 EP0241380A1 (de) 1987-10-14
EP0241380B1 true EP0241380B1 (de) 1992-01-08

Family

ID=9334147

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87400803A Expired - Lifetime EP0241380B1 (de) 1986-04-11 1987-04-09 Verfahren und Vorrichtung zur Strahlfokussierung von Gruppenantennen auf einen Prüfpunkt

Country Status (4)

Country Link
US (1) US4870423A (de)
EP (1) EP0241380B1 (de)
DE (1) DE3775806D1 (de)
FR (1) FR2597268B1 (de)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2236431B (en) * 1989-08-30 1993-11-03 Marconi Gec Ltd Antenna array
US5235342A (en) * 1989-08-30 1993-08-10 Gec-Marconi, Ltd. Antenna array with system for locating and adjusting phase centers of elements of the antenna array
US5228006A (en) * 1992-07-20 1993-07-13 Westinghouse Electric Corp. High resolution beam former apparatus
US6011512A (en) * 1998-02-25 2000-01-04 Space Systems/Loral, Inc. Thinned multiple beam phased array antenna
US7725167B2 (en) * 2005-07-13 2010-05-25 Clemson University Microwave imaging assisted ultrasonically
FR2941333B1 (fr) 2009-01-20 2012-12-14 Satimo Sa Systeme d'emission de faisceaux electromagnetiques a reseau d'antennes.
IT1395141B1 (it) * 2009-08-06 2012-09-05 Siae Microelettronica Spa Metodo e apparecchiatura per la ricostruzione di segnali multipli ad alta frequenza trasmessi su un unico canale di ponti radio.
EP2574378B1 (de) 2011-09-19 2016-09-14 Salomon S.A.S. Bindung für einen Schuh auf einem Gleitbrett

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3140490A (en) * 1961-11-30 1964-07-07 Sichak Associates Communication system with automatic antenna beam steering
US3757333A (en) * 1962-02-13 1973-09-04 Philco Ford Corp Receiving antenna system
US3806931A (en) * 1971-10-26 1974-04-23 Us Navy Amplitude modulation using phased-array antennas
US3859622A (en) * 1973-01-15 1975-01-07 Gen Electric Electronic scanning switch for sonar
US3878520A (en) * 1973-01-24 1975-04-15 Stanford Research Inst Optically operated microwave phased-array antenna system
US4010474A (en) * 1975-05-05 1977-03-01 The United States Of America As Represented By The Secretary Of The Navy Two dimensional array antenna
US3993999A (en) * 1975-05-16 1976-11-23 Texas Instruments Incorporated Amplitude modulation scanning antenna system
US4186398A (en) * 1975-06-09 1980-01-29 Commonwealth Scientific And Industrial Research Organization Modulation of scanning radio beams
US4028702A (en) * 1975-07-21 1977-06-07 International Telephone And Telegraph Corporation Fiber optic phased array antenna system for RF transmission
US4121221A (en) * 1977-03-14 1978-10-17 Raytheon Company Radio frequency array antenna system
US4190818A (en) * 1977-08-25 1980-02-26 The United States Of America As Represented By The Secretary Of The Navy Digital beamsteering for a parametric scanning sonar system
US4166274A (en) * 1978-06-02 1979-08-28 Bell Telephone Laboratories, Incorporated Techniques for cophasing elements of a phased antenna array
US4189733A (en) * 1978-12-08 1980-02-19 Northrop Corporation Adaptive electronically steerable phased array
FR2448231A1 (fr) * 1979-02-05 1980-08-29 Radant Et Filtre spatial adaptatif hyperfrequence
US4467328A (en) * 1981-10-26 1984-08-21 Westinghouse Electric Corp. Radar jammer with an antenna array of pseudo-randomly spaced radiating elements
GB2141876B (en) * 1983-06-16 1986-08-13 Standard Telephones Cables Ltd Optical phased array radar
US4649393A (en) * 1984-02-17 1987-03-10 The United States Of America As Represented By The Secretary Of The Army Phased array antennas with binary phase shifters
US4701762A (en) * 1985-10-17 1987-10-20 Sanders Associates, Inc. Three-dimensional electromagnetic surveillance system and method

Also Published As

Publication number Publication date
US4870423A (en) 1989-09-26
DE3775806D1 (de) 1992-02-20
FR2597268B1 (fr) 1988-06-24
FR2597268A1 (fr) 1987-10-16
EP0241380A1 (de) 1987-10-14

Similar Documents

Publication Publication Date Title
EP0050060B1 (de) Bilderzeugungssystem mit gleichzeitiger mehrfacher Aussendung
EP0472709B1 (de) Vorrichtung zur erzeugung von optischen verzögerungen und deren anwendung in einem system zur optischen steuerung einer abtastantenne
EP0415818B1 (de) Steuerung der Ausrichtung für Antennensystem mit elektronisch gesteuerter Auslenkung und Strahlformung durch Berechnung
EP0107552B1 (de) Interferometrisches Sonargerät durch Anwendung nichtlinearer akustischer Eigenschaften
CA2318378C (fr) Transducteur ultrasonore de contact, a elements multiples
EP0173617B1 (de) Sender-Empfängersysteme für Laserbilderzeugung
FR3058227A1 (fr) Radar fmcw multifaisceaux, notamment pour automobile
EP0732803A1 (de) Verfahren und Vorrichtung zum Demodulieren durch Abtastung
EP0036794A1 (de) Akustisches Abbildungssystem
EP0241380B1 (de) Verfahren und Vorrichtung zur Strahlfokussierung von Gruppenantennen auf einen Prüfpunkt
EP3749949B1 (de) Terahertz-reflexionsbildgebungssystem
EP0287444B1 (de) Vorrichtung zur optischen Steuerung einer Abtastantenne
WO1988008529A1 (fr) Dispositif de mesure, en une pluralite de points, du champ micro-onde diffracte par un objet
EP2039021B1 (de) Verfahren und vorrichtung zur übertragung von wellen
FR2674028A1 (fr) Procede et dispositif de determination du diagramme de rayonnement d'une antenne.
FR2766574A1 (fr) Procede d'observation de distribution d'ondes base sur une observation d'hologramme
CA2840848C (fr) Dispositif pour detecter des objets tels que des mines
WO2019170907A1 (fr) Procedes et systemes d'imagerie acousto-optique
BE1031268B1 (fr) Capteur radar à micro-ondes de formation d'image
Khoury et al. Homodyne and heterodyne imaging through a scattering medium
FR2692999A1 (fr) Sonde pour échographie et son application à l'échographie.
FR2632417A1 (fr) Dispositif de mesure, en une pluralite de points alignes, du champ micro-onde rayonne par une source
Rogov et al. Quadrature time-integrating acousto-optic correlator
FR2541786A1 (fr) Dispositif d'imagerie optique a detection heterodyne
EP0928042A1 (de) Breitbandige Detektionsvorrichtung, insbesondere für Radar

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE GB NL

17P Request for examination filed

Effective date: 19880411

17Q First examination report despatched

Effective date: 19900307

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE GB NL

REF Corresponds to:

Ref document number: 3775806

Country of ref document: DE

Date of ref document: 19920220

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19920331

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19920430

Year of fee payment: 6

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19930407

Year of fee payment: 7

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19931101

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19940101

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19940409

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19940409