EP0110479B1 - Dünne Doppelstrahlerrichtantenne für Mikrowellen - Google Patents
Dünne Doppelstrahlerrichtantenne für Mikrowellen Download PDFInfo
- Publication number
- EP0110479B1 EP0110479B1 EP83201682A EP83201682A EP0110479B1 EP 0110479 B1 EP0110479 B1 EP 0110479B1 EP 83201682 A EP83201682 A EP 83201682A EP 83201682 A EP83201682 A EP 83201682A EP 0110479 B1 EP0110479 B1 EP 0110479B1
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- EP
- European Patent Office
- Prior art keywords
- antenna
- semi
- width
- microstrip line
- band
- 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
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
- H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
- H01Q13/10—Resonant slot antennas
Definitions
- the invention relates to a dual directional microwave antenna capable of radiating decimetric or centimeter waves over a narrow angular range, the median angle ⁇ o of which belongs to the range 5 ° -85 °, geometrically formed by a volume of substantially rectangular parallelepiped shape. of thickness e, of length L and of width I t and, technologically speaking, of a support material of thickness h and dielectric constant e r whose surface is almost entirely metallized, said antenna being intended to be pressed on the outer wall of a missile or aircraft.
- a preferred field of application of such antennas is that of proximity rockets or the radar equipment of a missile in emission or in reception.
- it is desired to have a radiation diagram in the form of a conical half-sheet or of a complete conical sheet directed towards the front of the missile, with a pronounced rising front of the main lobe, which is inclined at an angle 8 0 relative to the axis of the missile.
- the angle 8 0 belongs, for this application, to the range 20 ° -70 ° and the secondary lobes having a firing angle close to 90 ° must have a reduced amplitude of at least 15 to 20 dB compared to the main lobe , so that the radiation towards the ground, in particular, is as attenuated as possible.
- an antenna installed on the outer wall of a missile must be of reduced dimensions and conform as much as possible to the generally curved shape of this wall so as not to distort the aerodynamic properties of the latter and to have good mechanical strength and limited heating given the displacement of the missile at high speed in the air.
- An essential characteristic of this type of antenna is to present a wide roll diagram, the reading of which, when the antenna is placed on a cylinder, is very close to a cardioid.
- the diagram in the meridian plane is directional and orientable as a function of the frequency of use.
- the adaptation band must be around 15% for a standing wave rate of 2 (90% of the transmitted power).
- Directive antennas of the type described in the preamble are known in particular from the article "Traveling-wave slot antennas" by J. H. Hines et al. published in Proceedings of the Ire (pages 16241631), volume 41, no.11 of November 1953, IEEE New York (US).
- This article relates in particular to a directive antenna with a slot for very high frequencies filled with a dielectric material. More specifically, this known antenna is constituted by a groove perpendicular to the ground plane, which has several drawbacks: the antenna is both too wide (deep) and too thick. The excess width (depth) makes it difficult to place the antenna on the wall of an aircraft in particular, its technological implementation is delicate, and the too great thickness does not allow perfect control of the antenna radiation pattern.
- Thin structure antennas are also known which make use of printed circuit technology, in particular of the type described in French patent application No. 2,481,526 in the name of the applicant.
- This last antenna has the advantages of reduced overall dimensions and simple realization desired but is not directive: it functions like a cavity, in resonant mode, and radiates in the manner of a doublet, its diagram having the shape of a half-torus (angle 8 0 equal to 90 °) whose axis merges with the axis of the aircraft on which it is located.
- Also known from document FR-A-2 364 548 is a two-band microstrip antenna using integrated circuit technology and operating in resonant mode with a radiation pattern widely open at each of the operating frequencies.
- Other known antennas such as paved antennas or flat antennas using printed circuit technology also function as a doublet, which also excludes them from the field of application desired for the present invention.
- An object of the present invention is to provide a double directional antenna with a thin structure of simple construction.
- Another object of the invention is to produce a double directional antenna with a thin structure whose roll diagram is as wide as possible.
- Yet another object of the invention is to produce a double directive antenna with a thin structure, the pitch diagram of which has very attenuated secondary lobes for a firing angle close to 90 °.
- Yet another object of the invention is to provide a double directional antenna with a thin structure, the pitch diagram of which has very attenuated secondary lobes.
- the antenna defined in the preamble is remarkable in that the radiating part of the antenna at the sole location of which the dielectric material is in contact with the ambient medium, without taking into account the presence of a possible radome, is reduced to a rectilinear strip of fixed width d, which extends over a first large face of said parallelepiped in the direction of the length so as to divide in two substantially equal metallized half-surfaces said first large face, the width d of said strip being of the order of several units of times the thickness e, the second large metallized face constituting the ground plane of the antenna, the two large faces being connected at their external lateral edges by short circuits, that a microstrip line which crosses said strip electrically connects said two half-surfaces at points on their free edge whose predetermined position is located near a first end of each of said half-surfaces, that the antenna socket is located at a predetermined point on said microstrip line
- the basic idea of the invention consists first of all in making an elementary directional antenna with a continuous slot of parallelepiped shape comprising between its two large metallized faces, a thin dielectric material, and at least one short circuit which extends over one medium face, the other medium face consisting of a dielectric constituting a radiation slit and one of the large metallized faces which extends beyond the slit constituting the ground plane, and then to pair two of these antennas in putting them next to each other, at the level of the slot, their ground planes being combined.
- the common points between said microstrip line and said free edge of each half-surface are preferably located at a distance substantially equal to: N 4 cos ⁇ o relative to the respective first ends of said half surfaces.
- the antenna is remarkable in that said two metallized half-surfaces are offset longitudinally by a distance D less than or equal to A to create between their free edges a geometric phase shift of value predetermined, said microstrip line having a longitudinal portion which extends over a length substantially equal to D in the middle of said strip.
- the contact points between the microstrip line and said two half-surfaces have an electrical phase shift capable of essentially ensuring the addition of the fields generated in phase for the predetermined angle 6 o on either side of said strip at any point where the free edges of said two half-surfaces are opposite.
- a second preferred embodiment in which there is substantially no longitudinal offset between the two metallized half-surfaces (the two elementary antennas) is remarkable in that said microstrip line extends in substance perpendicular to said strip and comprises substantially in its center said socket, and that said two metallized surface halves have widths l 1 and 1 2 slightly different and which vary along the antenna, so that the outer edge of a half surface has a shape slightly convex while the other half-surface has an outer edge of slightly concave shape, so that the fields generated on either side of said strip are substantially in phase opposition near said first end of the antenna and in phase in the middle of the antenna.
- a third embodiment is remarkable in that the antenna according to the invention is sectoral and for this purpose comprises a microstrip line which extends in substance perpendicularly to said strip and which is provided substantially in its center with said socket, and that the width l 1 , respectively 1 2 , of each half-surface is constant, the dimensions 1 1 and 1 2 differing from each other by a few percent.
- a fourth embodiment of the directional antenna according to the invention for which a good roll diagram substantially in the shape of a cardioid is required is remarkable in that said strip has a width d reduced by around twice the thickness e of the antenna.
- the antenna AE shown in FIG. 1 is intended to transmit or receive waves of very high frequencies, of the order of several GHz (decimetric or centimetric waves). It is constituted by two conducting planes 1 and 2, constituting its largest faces, connected by a narrow perpendicular wall 3 also conducting, known as the short-circuited wall, thus delimiting an area 4 indicated in broken lines which is called radiation slot.
- the space between the planes 1, 2 and 3 may contain air but is preferably filled with dielectric material such as epoxy glass or teflon glass for example whose thickness h is of the order of magnitude of the mm for Teflon glass and a few mm for epoxy glass.
- the antenna is supplied at a point P on the side 1 which is called the supply side, the side 2 which is opposite it constituting the ground plane.
- This metallized ground plane comprises at least the rectangular part located opposite the face 1.
- the antenna is formed from a rectangular parallelepiped containing the dielectric, of length L, of width I and of thickness e (overall thickness) of which at least the two large faces (Lx I) and one medium surface face (Lxe) are metallized, the small faces (Ixe) being or not metallized.
- Perpendicular coordinate axes o x, o y, o z are chosen such that the axis o z which is parallel to the axis of the aircraft or of the antenna support missile extends in the direction of the length L of the antenna, the axis o x in the direction of the width 1 and the axis o y in the direction of the thickness e.
- the length L of the antenna is of the order of at least twice the wavelength ⁇ of the wave that it is desired to transmit or receive and the width 1 at least ten times less than L.
- the radiation pattern obtained is directional, i.e. the pitch diagram, ' in the meridian plane yoz, has a main lobe in one direction o u which makes an acute angle ⁇ ° with respect to the oz axis.
- the antenna radiation pattern has the shape of a conical half-layer for the main lobe and each secondary lobe; it is symmetrical with respect to the meridian plane, and the roll diagram, taken on a cone with center 0 and axis oz, affects the shape of a cardioid for any value of the angle e when the antenna is plastered along the meridian of a surface of revolution, that is to say the widest roll diagram that it is possible to obtain.
- Such a diagram implies that the antenna operates in the resonant mode in the direction o x and in quide mode (traveling waves) in the direction o z.
- the electric field vector is maximum at the level of the slot 4 or more precisely at a few tenths of a millimeter beyond the slot and zero at the level of the short-circuited wall 3.
- a and b are expressed as a function of the magnitudes G and B (see formulas (3) and (4)).
- the values of ⁇ z and ⁇ z (formulas (10) and (11)) can finally be obtained, via the values of G and B and of a and b according to the six characteristics of the antenna indicated below. above.
- the ohmic and dielectric losses linked to the materials used must also be integrated. These losses are referenced ⁇ zo , the total attenuation in the direction oz being referenced ⁇ zt , with:
- the computation of the ohmic losses noted ⁇ 1 can be carried out starting from the literal expression of the transported power between two transverse sections distant from ⁇ z of the antenna then by using the equations of Maxwell for the modes TE.
- the dielectric losses ⁇ 2 are due to the fact that the dielectric constant of a material is expressed by a complex number, that is:
- the diagram in the meridian plane is obtained from the law of illumination of the radiated fields.
- the antenna of FIG. 1 which we assume, by way of generalization, that the width I varies as a function of z. This gives a variation of a t and ⁇ z as a function of z.
- N the radiating length of the antenna, we can discretize the law I (z) with a step p such that N / p is integer. Therefore the antenna is presented according to the diagram below:
- C 2 0 when there is an ideal suitable load at the end of the antenna, C being generally a complex number.
- the multiple antennas according to the invention described below which consist of two elementary antennas according to FIG. 1 paired, have two independent ⁇ or substantially independent laws of illumination.
- the pitch diagram in particular, it suffices to add the radiated fields along oz, then to apply formula (27) as we would apply it to the elementary antenna.
- the antenna of FIG. 1 for which the width 1 would be constant along oz, would have an exponential amplitude law of illumination and the first secondary lobe would be located at -7 dB only below the main lobe.
- I as a function of z for this antenna
- ⁇ zt and ⁇ z variable as a function of z.
- the variation of ⁇ zt causes an amplitude fluctuation of the exponential law and the variation of ⁇ z creates a greater fluctuation of the phase law.
- the absence of a suitable load at the end of the antenna can create a reflected wave whose phase and amplitude can modify by lowering this or that secondary lobe, but at the cost of the appearance of a rear lobe corresponding to the main lobe of the reflected energy.
- the performance of the elementary antenna is therefore limited and insufficient for the applications envisaged.
- two of these paired antennas according to the invention as described below make it possible to obtain very interesting radiation patterns.
- the antenna is presented as a volume of substantially rectangular rectangular shape of thickness e, length L and width 1, and, from the technological point of view, it consists of a support material dielectric constant e r , for example epoxy glass or teflon glass, the surface of which is almost entirely metallized.
- the radiating part of the antenna at the only location where the internal dielectric material is in contact with the ambient medium (unless there is a possible radome) is reduced to a band of fixed width d, which extends over a large face of the parallelepiped in the direction of the length so as to divide this large face into two substantially equal metallized half-surfaces, the width d being of the order of several times the dimension e.
- the second large metallized face constitutes the ground plane of the antenna.
- the two large faces are connected at their outer edges by short circuits (metallized walls or aligned metallized holes).
- a microstrip line which crosses the strip of width d electrically connects the two half-surfaces at points on their free edge near a metallized end of each of the half-surfaces and comprises the antenna socket at a predetermined point.
- the thickness e is of the order of that of a printed circuit.
- the length L is greater than 2A and, in general, in a relationship such as the thickness e, that the energy reflected at the far end of the antenna is essentially negligible.
- the width I t of the antenna is between 0.2 ⁇ and 0.6 ⁇ .
- the double antenna shown in FIG. 3 constitutes a first embodiment of the invention and results from the association of two elementary antennas which are generally identical (at least as regards law I (z)).
- this antenna is characterized by a longitudinal offset of the two half-surfaces 6, 7 by a predetermined distance D, by the fact that the dimension d is of the order of 6 to 8 times greater than the thickness e and that the microstrip line 8 has a longitudinal part which extends over a length substantially equal to D in the middle of the strip 11 of width d.
- the end close to the supply of the half-surface 6 as well as the remote end of the supply to the half-surface 7 are, in FIG. 3, formed by an alignment of metallized holes such as 12 which locally bring the two large faces into contact, thus constituting short circuits.
- the antenna diagram according to FIG. 3 can be modeled by making sure to add the fields in phase in the desired main direction and, moreover, add the fields in phase opposition in a direction that one wishes not to not enlighten. This can be obtained by acting on parameter D and / or on the electrical phase shift between the supply points P 6 and P 7 achieved by choosing the location of the antenna socket on the microstrip line, for example at a point 13.
- the composition of the fields involves not only the dimension D but also the dimension d which is the approximate distance separating the phase centers of each antenna. Compared to the elementary antenna of FIG.
- Each dashed line curve 15, 16, 17 represents the amplitude of the incident field E (z) at a given instant
- each mixed line curve the amplitude of the field reflected at the end of the antenna distant from the point d 'power supply
- each solid line curve 18, 19, 21 covers the incident field, the phase of which varies over time.
- the geometric phase shift D appears clearly in the figure. If the antenna socket was located in the middle of the microstrip line, the electrical phase difference between curves 15 and 16 would be equal to 180 °. In FIG.
- the instantaneous fields represented in 15 and 16 are in phase, which corresponds to an asymmetrical location of the socket on the microstrip line 9 suitable for ensuring the phase opposition of the electric fields between the supply points P 6 and P 7 of the half-antennas.
- the choice of the geometric and electrical phase shifts of the antenna constitutes an optimization in this sense. That the geometrical phase shift corresponds substantially to the wavelength of the field E (z) and that the chosen electrical phase shift attenuates the discontinuity of the fields as much as possible when the wall is short-circuited close to the microstrip line 8.
- a so-called associated antenna according to FIG. 3 has for example the following characteristics: The radiating length being 3.3 ⁇ , this antenna is classified among the "short" antennas.
- the pitch diagram is indicated in FIG. 5 on which the amplitude curve of the measured radiated fields is shown in 23 in solid line and in broken lines in 24 the amplitude curve of the calculated radiated fields, the ordinates being shown in dB after normalization of the curves such that their vertex corresponds in amplitude and the abscissa in degrees, according to the classical Cartesian representation.
- the operating frequency used for the calculation is 3.08 GHz and the experimental frequency of 3.1 GHz.
- the angle ⁇ ° is close to 60 ° and the secondary lobes close to 90 ° are lowered to -20 dB, the direction 90 ° thus constituting a blind direction.
- the roll diagram, Figure 6 was measured with the antenna, the characteristics of which are given above, but for an operating frequency of 3.3 GHz.
- the type of representation is the same as for the pitch diagram, the angle ⁇ plotted on the abscissa being the angle at the center of a cone with center 0 and axis oz, (p being zero (or equal to ⁇ 180 °) in the meridian plane.
- the roll diagram of figure 6 has been measured for three values of 8 which appears here as a parameter.
- We observe a very large diagram of cardioid in the direction main (8 46 °), which is sought above all.
- the TOS of all the antennas described in this text can be improved if necessary by a judicious choice of the dielectric material used and its thickness, in relation to the operating frequency envisaged.
- the problem of adaptation is facilitated for the associated antenna because the dimension d is relatively large and that, therefore, the middle part 9 of the microstrip line which extends longitudinally does not disturb the field emitted by each half-antenna, which makes it possible to place the transition (points P 6 , P 7 ) at any point on the free edge of each half-antenna 6, 7.
- the antenna of FIG. 3 is applicable in the case where the antenna is short (N ' ⁇ 5A), which leads to the radiation characteristics described above. However, if the available length is longer important it may be preferable to use two elementary antennas assembled in an array as shown in figure 7.
- the antennas according to FIG. 7 constitute a second and a third embodiment of the invention.
- this antenna is characterized by the fact that the microstrip line 26 extends in substance perpendicularly to the strip 27 of width d which separates the two half -surfaces 28 and 29 and also by the fact that these two metallized half-surfaces 28 and 29 have slightly different widths I 1 and I 2 , which gives this double antenna the qualification of additional antenna, the widths being able to elsewhere vary as a function of z as described below.
- the antenna socket is generally located in the middle of the microstrip line, at point 31. These characteristics different from those of the antenna in FIG. 3 lead to different radiation properties.
- the amplitude law of the complementary antenna presents the general aspect of the diagram of FIG. 8 where we have adopted the same type of representation as in FIG. 4.
- the instantaneous fields emitted by each elementary antenna 28, 29 are represented by the broken line curves 32, 33 respectively, the envelope of these fields, in solid line, being referenced 34, 35.
- the curves in dashed line indicate the fields reflected by the end of the antenna away from the feed point in the absence of a suitable load.
- FIG. 8c represents the addition of the curves of FIGS. 8a and 8b.
- a first variant (second embodiment) consists in slightly bending the short-circuited side walls of the two half-antennas, which amounts to making the widths I 1 and 1 2 variable as a function of z.
- These side walls are for example curved as shown in broken lines, one being convex (1 1 widens towards the middle of the antenna), while the other is concave (1 2 tapers towards the middle of antenna).
- a complementary antenna according to this first variant has for example the following characteristics: Law giving 1 1 and 1 2 as a function of z for the two half-antennas (in mm):
- the radiation diagrams are those shown in Figures 9 for the pitch diagram and 11 for the roll diagram where we adopted the same mode of representation as in Figures 5 and 6 respectively.
- the widths 1 1 and 1 2 of the half-antennas are fixed but differ slightly from each other, which constitutes a third embodiment of the invention.
- An additional antenna according to this second variant has, for example, characteristics identical to that described in the preceding paragraphs except for the widths which here have the value:
- the operating frequency was gradually increased, of the order of 100 to 200 MHz, we would observe a simultaneous shift to the left of the vertices of these lobes, the latter tending to approach the one of the other until disappearance of the trough 38. Conversely, a gradual decrease of the order of 100 to 200 MHz would cause a simultaneous shift to the right of the vertices of the two lobes which would tend to move away l 'from each other, the hollow 38 becoming more and more marked.
- the roll diagram is substantially that shown in FIG. 11 and the comments on this figure made above remain valid, the value G must here also be taken equal to: nh / 5A '.
- the adaptation of the antenna can be carried out as for the curved complementary antenna, with comparable performance (see the explanations given below in particular with reference to FIG. 14).
- FIG. 12 represents, with cutaway, an antenna with contiguous slits whose characteristics, apart from the reduction in width of the band 39, are the same as those of the complementary antenna of FIG. 7.
- the antenna having the following characteristics has been calculated, produced and tested:
- the quantity G is not corrected in this case and remains in accordance with formula 20 because the roll diagram obtained is practically a cardioid.
- the pitch diagrams calculated (broken line) and measured (solid line) are shown in Figure 13.
- the angle ⁇ ° is equal to 62 °.
- the secondary lobes are very attenuated (less than -20 dB) for: ⁇ ⁇ ° and for 8 close to 90 ° (angle for which there is a blind direction).
- the number of secondary lobes is reduced in comparison with FIG. 13 (the strong rear lobe being always present) and the angle ⁇ ° is located at 72 °.
- the number of rear lobes is increased with always a strong rear lobe at around -8 dB relative to the main lobe and the angle 8 0 is located at 52 °.
- the characteristic impedance of a rectangular waveguide of height h and width 21, filled with a dielectric of constant ⁇ r is given in the literature by: the impedance Z. being measured in the middle between the wide walls of the guide, at the intersection of a meridian plane and a transverse plane.
- an elementary antenna similar to that of FIG. 1 is such that the distribution of the electric and magnetic fields in the elementary antenna is the same as that of one side of the guide.
- the characteristic impedance of an elementary antenna is therefore such that put in parallel with itself, we find Z e , that is:
- the characteristic impedance of the line transmitting energy to the antenna is equal to Z c (AE) .
- the antenna is not infinite, it is necessary to place the transition at a distance (n positive integer) of any short circuit, unless n is large enough for the level of reflected radiation to be negligible, which is generally the case with the antenna according to the invention. It will be noted that in the case of complementary antennas the impedances characteristic of the two elementary antennas are in parallel and therefore lead to the impedance Z o .
- the antenna of FIG. 14 is similar to that of FIG. 7.
- its remaining part differs in that the microstrip line 41 crosses the strip of width d slightly at an angle such that it opens at the feed point P 42 relating to the half-surface 42 in a voluntarily enlarged part of the supplied end of the antenna (width 1 0 such that I ° > I 1 > I 2 ) while the opposite point P 43 opens into the non-enlarged radiating part of the elementary antenna located opposite.
- the widening to 1 0 on either side of the supplied end of the antenna is accompanied by a shortening of this end which is of the same order of magnitude.
- the adaptations are as follows: for the second and third embodiments, ie the non-sectoral complementary antenna and the sectoral complementary antenna of FIGS. 9 to 11, the characteristic impedance of the half-antenna 28 is close 55 Q (width I ° ).
- the characteristic impedance of the half-antenna 29 is 155 Q for the complementary non-sectoral antenna and 140 Q for the complementary sectoral antenna (width I 2 ).
- the energy distribution is then theoretically around 3/4 for the elementary antenna of width I 1 and 1/4 for the elementary antenna of width 1 2 , i.e. a relative level in tension of 58% between the two elementary antennas. In practice, the relative level in real voltage obtained (diagram in FIG. 9) is not 58% but 38%.
- the TOS obtained for this antenna is of the same order as a theoretical TOS of -dB obtained for an overall impedance of the antenna of:
- the energy distribution is 28% for the elementary antenna of width I 1 and 72% for the other elementary antenna, i.e. a relative level in theoretical voltage of 62% between the two elementary antennas .
- the relative real voltage level obtained (diagram in Figure 10) is 60%.
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Claims (11)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8220290A FR2537347B1 (fr) | 1982-12-03 | 1982-12-03 | Antenne directive double pour hyperfrequences a structure mince |
FR8220290 | 1982-12-03 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0110479A1 EP0110479A1 (de) | 1984-06-13 |
EP0110479B1 true EP0110479B1 (de) | 1988-05-18 |
Family
ID=9279765
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP83201682A Expired EP0110479B1 (de) | 1982-12-03 | 1983-11-29 | Dünne Doppelstrahlerrichtantenne für Mikrowellen |
Country Status (4)
Country | Link |
---|---|
US (1) | US4591865A (de) |
EP (1) | EP0110479B1 (de) |
DE (1) | DE3376718D1 (de) |
FR (1) | FR2537347B1 (de) |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2682772B1 (fr) * | 1991-10-18 | 1993-12-03 | Thomson Csf | Procede et dispositif de mesure de courtes distances par analyse du retard de propagation d'une onde. |
FR2688900B1 (fr) * | 1992-03-20 | 1994-05-13 | Thomson Csf | Procede et dispositif de determination du passage a une distance preselectionnee d'un point reflecteur a l'aide du temps de propagation d'une onde continue. |
FR2764738B1 (fr) | 1997-06-13 | 1999-08-27 | Thomson Csf | Dispostif d'emission ou de reception integre |
FR2769154B1 (fr) * | 1997-09-30 | 1999-12-03 | Thomson Csf | Dispositif de synchronisation precise |
FR2776888B1 (fr) | 1998-03-27 | 2000-06-16 | Thomson Csf | Structure de circuits electroniques a encombrement optimise en fonction du volume disponible |
US7079070B2 (en) * | 2001-04-16 | 2006-07-18 | Alliant Techsystems Inc. | Radar-filtered projectile |
US6618017B1 (en) * | 2002-05-20 | 2003-09-09 | The United States Of America As Represented By The Secretary Of The Navy | GPS conformal antenna having a parasitic element |
US7891298B2 (en) | 2008-05-14 | 2011-02-22 | Pratt & Whitney Rocketdyne, Inc. | Guided projectile |
US7823510B1 (en) | 2008-05-14 | 2010-11-02 | Pratt & Whitney Rocketdyne, Inc. | Extended range projectile |
KR101239737B1 (ko) * | 2011-02-18 | 2013-03-06 | 한국과학기술원 | 니트리도실리케이트 물질 및 희토류로 도핑된 알칼리토류 니트리도실리케이트 형광체의 제조 방법 |
US10318904B2 (en) | 2016-05-06 | 2019-06-11 | General Electric Company | Computing system to control the use of physical state attainment of assets to meet temporal performance criteria |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2648002A (en) * | 1945-11-19 | 1953-08-04 | Us Navy | Dielectric antenna |
FR976767A (fr) * | 1948-10-16 | 1951-03-22 | Radio Electr Soc Fr | Procédé de fabrication de systèmes rayonnants et de dispositifs connexes |
US2822542A (en) * | 1954-10-18 | 1958-02-04 | Motorola Inc | Directive antenna |
FR2309122A5 (fr) * | 1969-07-08 | 1976-11-19 | Trt Telecom Radio Electr | Perfectionnements aux antennes directives a fente pour tres hautes frequences |
US3739391A (en) * | 1972-06-12 | 1973-06-12 | Us Air Force | Metallized channel guide antenna |
US3971032A (en) * | 1975-08-25 | 1976-07-20 | Ball Brothers Research Corporation | Dual frequency microstrip antenna structure |
FR2507825A1 (fr) * | 1981-06-15 | 1982-12-17 | Trt Telecom Radio Electr | Antenne directive pour tres hautes frequences a structure mince |
-
1982
- 1982-12-03 FR FR8220290A patent/FR2537347B1/fr not_active Expired
-
1983
- 1983-11-29 EP EP83201682A patent/EP0110479B1/de not_active Expired
- 1983-11-29 DE DE8383201682T patent/DE3376718D1/de not_active Expired
- 1983-11-30 US US06/556,506 patent/US4591865A/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
FR2537347A1 (fr) | 1984-06-08 |
EP0110479A1 (de) | 1984-06-13 |
DE3376718D1 (en) | 1988-06-23 |
FR2537347B1 (fr) | 1985-09-27 |
US4591865A (en) | 1986-05-27 |
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