EP0139920B1 - Mikrowellenschranke - Google Patents

Mikrowellenschranke Download PDF

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Publication number
EP0139920B1
EP0139920B1 EP84109376A EP84109376A EP0139920B1 EP 0139920 B1 EP0139920 B1 EP 0139920B1 EP 84109376 A EP84109376 A EP 84109376A EP 84109376 A EP84109376 A EP 84109376A EP 0139920 B1 EP0139920 B1 EP 0139920B1
Authority
EP
European Patent Office
Prior art keywords
aerial
barrier
microwaves
antenna
ground
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
Application number
EP84109376A
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German (de)
English (en)
French (fr)
Other versions
EP0139920A1 (de
Inventor
Ian T. Simpson
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.)
Hoermann Sicherheitstechnik GmbH
Original Assignee
Hoermann Sicherheitstechnik GmbH
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 Hoermann Sicherheitstechnik GmbH filed Critical Hoermann Sicherheitstechnik GmbH
Publication of EP0139920A1 publication Critical patent/EP0139920A1/de
Application granted granted Critical
Publication of EP0139920B1 publication Critical patent/EP0139920B1/de
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2491—Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field

Definitions

  • Microwave cabinets are used to secure rooms and protection zones against intruders.
  • the microwave transmitter and the microwave receiver are arranged at the opposite ends of a line to be monitored. If the microwave antenna beam is completely or partially interrupted by an intruder, a circuit provided in the receiver triggers an alarm signal.
  • microwave barrier The area covered by such a microwave barrier must, on the one hand, extend to the ground (so that an intruder cannot crawl under the beam) and, on the other hand, must reach high enough (to prevent it from jumping over).
  • a known microwave barrier uses a single antenna beam or a number of antenna elements which determine a single beam propagation angle (hereinafter referred to as beam width). As will be explained in more detail below, this results in an unsatisfactory compromise between the requirements of good surveillance near the ground (protection against crawling under) and in height (protection against skipping).
  • Microwave barriers must generally have a range (length of the protected route) between 10 and 200 m. An alarm is to be triggered when an intruder tries to crawl under the microwave barrier, run through the barrier or jump over it. To meet these requirements, the monitoring zone must extend to the ground on the one hand and to a height of over 2 m on the other.
  • the beam width corresponds to the angle at which the radiation spreads from the antenna. Numerically, it corresponds to the angular range in which the main part of the microwave signal is focused.
  • an antenna with an aperture of 20 cm is arranged at a height of 100 cm above the floor (cf. FIG. 1), a beam width of 8.6 ° results at a wavelength of 3 cm.
  • the antenna beam thus diverges by 4.3 ° up and down. This antenna beam strikes the ground or the 2 m height at a distance of 12 m (from the transmitter or receiver).
  • the signal picked up by the receiver consists of two main components, namely the direct signal and the signal reflected on the ground (cf. the schematic representation in FIG. 2).
  • the two components of the received signal thus have a phase shift 0.
  • the size of the received signal therefore depends on the size of the component (a) reflected on the ground and on the phase shift (0).
  • the size of the component reflected on the ground is equal to the direct component.
  • the phase shift of 180 °, which the wave reflected on the ground experiences during the reflection, also applies to both horizontally and vertically, accordingly circularly polarized waves.
  • the component reflected on the ground is therefore a general problem with microwave barriers, since it extinguishes the direct component at certain distances and certain mounting heights.
  • Practical microwave antennas focus the radiation in a beam.
  • the size of the signal reflected on the ground is also influenced by the beam width of the antenna. Broader rays give larger values of the signal reflected on the ground.
  • Fig. 3 illustrates the floor reflection effect for a vertical antenna with an aperture of 20 cm and a mounting height of 100 cm above the floor.
  • the diagram shows the dependence of the level of the received signal on the distance between transmitter and receiver.
  • the ordinate is divided into logarithmic units of the received signal level.
  • the distance between transmitter and receiver is plotted on the abscissa, likewise in logarithmic division. It can be seen that at certain distances, in particular at 68 m, the received signal is considerably weakened. The reason for this is that at these points the component reflected on the ground is out of phase with the direct component.
  • the antenna's beam width ensures these effects do not occur at very short distances, since the beam only hits the ground at a distance of 12m from both ends (corresponding to a total distance of 24m).
  • the dashed curve in FIG. 3 shows the influence of a reduction in the mounting height of the antenna by 10 cm.
  • the general course of the curve remains similar; the position of the minima changes, however. In practice, this leads to difficulties in cases where the effective mounting height changes due to the growth of vegetation or snowfall. This reduces the effective mounting height, which can lead to the received signal being too low in the minimum ranges to ensure reliable operation. This can result in false alarms and other malfunctions.
  • FIG. 4 shows in the fully drawn curve the situation with a mounting height of the antenna of 30 cm.
  • FIG. 3 shows that the relative received signal amplitude decreases continuously with the transmitter / receiver distance and that there are no cancellation effects (as in FIG. 3) within the required distance range.
  • the reduction in the mounting height compared to the conditions in FIG. 3 increases the signal reflected on the ground, but precludes complete phase opposition to the direct signal.
  • the first extinction occurs at a distance (between transmitter and receiver) of 6 m, i.e. at a value that is not required in practice.
  • the dashed curve in Fig. 4 shows the conditions for a mounting height of 20 cm. It can be seen that here too there is a smooth drop in the relative received signal amplitude with increasing distance and that there is no direct cancellation in the distance range shown.
  • the prior art also includes a microwave barrier (DE-A-2 806 448) in which the transmitter and the receiver have parabolic mirrors in conjunction with waveguides, with funnels with a rectangular cross-section opening onto the waveguides.
  • the waveguide and the funnel are adjustable with respect to the focal points of the parabolic mirrors.
  • the microwave field can be bundled or expanded in accordance with the local conditions; In particular, depending on the requirements, a narrow, high microwave field with a small floor space requirement, a narrow, oblique microwave field with a small floor space requirement and improved protection against skipping or a low, wide microwave field for securing a large floor area can be formed.
  • the problems of floor reflection discussed above also exist with this microwave barrier.
  • a microwave barrier is known (FR-A-2 125 182) which, in contrast to the explanations explained above, is based on a bidirectional energy flow.
  • a combined transmitter / receiver with two antennas arranged one above the other is arranged at one end of the microwave barrier, while a reflector is provided at the other end, which likewise consists of two antennas arranged one above the other.
  • the signal emitted by the transmitter and received by the one reflector antenna is sent back from the second reflector antenna to the receiver after phase modulation.
  • the two antenna beams running in the opposite direction are therefore not independent of one another, but are mutually dependent. Special measures for eliminating the effects of floor reflections are also not provided for in this microwave barrier.
  • the invention is therefore based on the object, while avoiding the disadvantages described, to develop a microwave barrier which ensures flawless protection both on the ground and in height, and which also avoids the disadvantages described of extensive extinction of the direct component by the component reflected on the ground and which finally gets by with relatively small antenna dimensions, in particular a small antenna aperture.
  • the transmitter and the receiver are equipped with one or more antennas which are arranged so close to the ground that there are no extinction effects due to ground reflection. This ensures a sufficient signal level for the system under all ground conditions.
  • at least one further antenna beam is also provided, which is emitted upwards at an angle at which the main part of the beam does not hit the ground. Under these conditions there is no signal reflected from the ground with respect to this upward beam; the change in signal level with distance therefore remains smooth, and there are no cancellation effects.
  • FIG. 5 shows the basic diagram of the two-beam system according to the invention.
  • a single transmitting and receiving antenna with an aperture of 20 cm is provided, the antenna beams being generated with a beam width of 8.6.
  • the beam axis of the lower antenna beam runs parallel to the ground; the beam axis of the upper antenna beam is inclined upwards from the horizontal by 8.6 °.
  • the lower antenna beam hits the ground at a distance of 4 m (from both ends of the monitored route) and reaches the 2 m height at a distance of 21 m from both End up.
  • the upper antenna beam does not hit the ground, so that no changes in the received signal level can occur due to ground reflections; the 2 m height reaches the upper antenna beam at a distance of 7 m from both ends.
  • Additional antenna beams can be provided to ensure additional height protection if necessary.
  • the circuit in the receiver is provided in such a way that an alarm is triggered if one of the several antenna beams is completely or partially interrupted.
  • FIG. 6 illustrates a complete exemplary embodiment of the microwave barrier according to the invention. It contains a microwave transmitter and a separate microwave receiver, both of which are arranged on a metallic base plate.
  • the microwave transmitter contains a microwave oscillator 1 which uses a GaAS field effect transistor. If the oscillator 1 is supplied with voltage by a driver stage 2, it generates an oscillation with the desired microwave frequency. The microwave signal generated in this way is fed through a splitter 3 to two antennas 4, 5. The lower antenna 5 is aimed directly at the receiver, while the upper antenna 4 radiates the radiation obliquely upwards, so that the main part of the radiation does not touch the ground.
  • the microwave transmitter thus contains two relatively small antennas with two independent beam directions.
  • the receiver is located at the other end of the line to be monitored.
  • the incoming microwave radiation is picked up by two antennas 6 and 7.
  • the lower antenna 7 is arranged near the ground, so that the radiation component reflected on the ground can never extinguish the radiation coming directly from the transmitter.
  • the upper antenna 6 is arranged such that its axis of maximum sensitivity is inclined obliquely upwards, while this antenna 6 has only a very low sensitivity to the signal reflected from the ground.
  • the signal received by antennas 6 and 7 is combined in a microwave mixer 8. This mixer 8 delivers an output signal which corresponds to the vector sum of the input signals supplied by the two antennas.
  • the resulting sum signal is rectified in a microwave detector 9, which can be formed, for example, by a Schottky blocking detector diode.
  • a microwave detector 9 which can be formed, for example, by a Schottky blocking detector diode. This circuit delivers a small output voltage proportional to the size of the sum signal.
  • the rectified signal is amplified by a series of amplifiers, the degree of amplification of which is variable and is automatically set by means of a circuit 10 with automatic gain control.
  • This circuit 10 effects a slow adjustment of the gain and compensates for different installation distances as well as long-term effects, such as environmental changes, which are caused by growing grass or snowfall. Short-term changes, such as those caused by an intruder, do not trigger a change in the degree of amplification by the circuit 10. Rather, such changes in the received signal level reach the test and hold circuit 11.
  • the transmitter is designed so that it emits microwave pulses to save electricity. Accordingly, the signal picked up by the receiver is in the form of pulses.
  • the control signal activating the transmitter is sent by a trigger generator 14 in the receiver via a connecting line to the transmitter.
  • the trigger signal also serves to activate the test and hold circuit 11 in the receiver, which converts the pulse output of the circuit 10 into a continuous signal proportional to the size of the output pulse. If an intruder comes into the area of the microwave barrier, this results in a low-frequency change in the output signal of the test and hold circuit 11.
  • a threshold detector 12 processes this low frequency signal and determines the size and speed of the intruder. If the change in amplitude exceeds a predetermined threshold, an alarm output device 13 is actuated. The behavior of the system depends on where the attempt to penetrate took place.
  • An intruder creeping on the floor causes a change in the signal picked up by the lower antenna 7.
  • An intruder who tries to jump over the microwave barrier near the transmitter interrupts the beam emitted by the upper antenna 4.
  • part of this signal is reflected to the receiver, which - depending on the relative position of the intruder - is determined either by the upper or by the lower antenna 6 or 7.
  • An on dringling which tries to jump over the microwave barrier near the receiver, reflects part of the transmitted signal to the upper receiving antenna 6 and causes a change in the signal here.
  • an attempt at intrusion will cause the received signal to change at one or both of the receiving antennas.
  • This signal change is processed by the downstream circles.
  • the antennas 4, 5, 6 and 7 are designed in planar form. Antennas 4 and 6 have the same beam direction angle, but a different beam direction angle than antennas 5 and 7 (which in this respect are identical to one another).
  • the oscillator 1, the splitter 3 and the driver stage 2 are arranged on a base plate 15a, which at the same time forms the mechanical holder and the conductive plane (ground) necessary for the function of the microwave circuit.
  • a conductive base plate 15b in the receiver In a corresponding manner, all components are arranged on a conductive base plate 15b in the receiver.
  • the antennas 6 and 7 are provided in the same way as in the transmitter.
  • the functions of the mixer 8 and the detector 9 are combined in a microwave receiving module 30.
  • the output of this receiving module 30 is connected to the input of a receiver circuit 31, which performs the functions of the circuit 10 with automatic gain control, the test and hold circuit 11, the threshold detector 12, the alarm output device 13 and the trigger generator 14.
  • planar antenna The function of the planar antenna is explained below, although in principle any antenna that generates a directed antenna beam can be used within the scope of the invention.
  • a planar antenna includes a pattern of metallic strips 19 that are etched on an insulating dielectric substrate 16. These strips 19 are thus at a certain distance from a conductive metallic base plate 17 (cf. FIG. 9).
  • the pattern of the metallic strips 19 contains a multiplicity of dipoles (of half wavelength) which are connected to feed lines.
  • a microwave signal is fed to the input connection 20 and is distributed over eight strips 19 which form the feed lines. The microwave signal supplied to these feed lines travels along these strips to the end 21 and thereby excites the dipoles 18.
  • Each dipole emits the microwave signal into the space above the planar antenna.
  • the distance between the individual dipoles can be selected such that the radiation components emanating from the individual dipoles add up in size and phase in a certain angular direction and thus generate a defined beam.
  • 10 shows a diagram of a feed line and the associated dipoles.
  • the microwave signal In the horizontal direction (FIG. 9) the microwave signal has the same amplitude and phase at every moment. This ensures that the maximum beam direction includes an angle of 90 ° with the horizontal plane of the substrate.
  • the effective dimension of the aperture a ⁇ cosa.
  • the main part of the energy radiated by an antenna lies within an angular range of a ⁇ 0/2.
  • the angle a In order to ensure that the upper beam does not experience any significant ground reflection, the angle a must be inclined upwards and larger than half the beam width (0/2) of the upper antenna. So it applies
  • the lower antennas 5 and 7 are dimensioned so that they deliver a maximum signal in the receiver.
  • the angle that the beam axis of these two antenna beams forms with the horizontal is chosen to be zero for this purpose.
  • Fig. 12 shows the resulting arrangement.
  • the upper antenna used has a vertical radiating aperture of 34 cm, the lower antenna of 32.5 cm. This results in a beam width of 5.0 ° for the upper antenna beam and a beam width of 5.3 ° for the lower antenna beam.
  • the upper antenna generates a beam that spreads upwards at an angle of 5.0 °.
  • the antennas are arranged on a rigid base plate, which ensures the correct relative position, at the same time forms the conductive metallic holder and represents a mounting plate for the electronic components.
  • the mounting heights of the antennas above the ground are shown in FIG. 13 for the exemplary embodiment explained.
  • the lower antenna beam hits the ground at a distance of 4 m; the upper antenna beam crosses the 2 m height at a distance of 6 m.
  • Such an arrangement performs good soil monitoring on the one hand and prevents attempts to skip the microwave barrier on the other.
  • FIGS. 14 and 15 show a variant with antennas arranged horizontally next to one another.
  • the transmitter is shown in FIG. 14 and contains a base plate 40 on which the remaining parts of the transmitter are arranged.
  • the oscillator 43, the splitter 44 and the driver stage 45 are arranged, as in the exemplary embodiment explained above, between the antennas 41 and 42, which are now arranged horizontally next to one another.
  • the antennas are designed as planar antennas.
  • the antenna 41 generates the lower antenna beam, the beam axis of which has an inclination of 0 °.
  • the antenna 42 generates the antenna beam directed upwards, which essentially does not touch the ground.
  • the receiver shown in FIG. 15 has two planar antennas 46, 47 (similar to those in the transmitter), also a reception module 48 and a receiver circuit 50.
  • the components mentioned are provided on a metallic base plate 49.
  • the antenna 46 generates the lower antenna beam, the maximum sensitivity of which lies at an angle 0 (with respect to the horizontal), while the antenna 47 generates the antenna beam directed upwards, which experiences practically no ground reflection.
  • the function of this embodiment corresponds to that of the variant with antennas arranged vertically one above the other.
  • the output signals of the two receiving antennas are added vectorially and rectified in the receiving module. If either the lower or the upper antenna beam is interrupted, an alarm signal is generated.
  • the structure of the antennas of this embodiment is slightly different from the previously explained embodiment.
  • 16 shows the configuration of the antenna generating the lower antenna beam.
  • the signal coming from the output 51 of the splitter is divided into eight transmission lines 52.
  • a number of half wavelength dipoles 54 are excited by the microwave running along the transmission lines 52.
  • the arrangement is such that the phase and magnitude of the signal on the transmission lines 52 are the same at corresponding points (approximately along the line 55) at all times.
  • the dipoles 54 are arranged in such a way that the combined radiation forms an antenna beam, the beam axis of which forms an angle of zero with respect to the horizontal and which is mainly polarized in the vertical plane.
  • the antenna arrangement is located on an insulating substrate 53, as in the previously explained exemplary embodiment.
  • the beam characteristic is shown in Fig. 17.
  • the antenna 53 is arranged near the ground 56.
  • the beam axis has an elevation angle of 0 °.
  • the structure and function of the antenna belonging to the lower antenna beam on the receiving side are essentially the same.
  • the transmission lines 57 are arranged in such a way that a different phase results for the dipoles 58 connected to the individual transmission lines 57.
  • the phase for the dipoles of each transmission line is selected by choosing the path length between the input 59 and the first dipole of the transmission line 57 concerned.
  • the height angle a of the beam axis (ie the direction of maximum beam strength, see Fig. 19) can then be determined using the formula: where 1 and d are the dimensions shown in FIG. 18 and He is the effective relative dielectric constant of the substrate.
  • FIGS. 20 and 21 A further exemplary embodiment of the invention, in which the antennas for generating (or for receiving) the upper and lower antenna beams are formed by a single, combined antenna, is shown in FIGS. 20 and 21.
  • the transmitter shown in FIG. 20 contains a planar antenna 60 which generates two separate antenna beams. It is excited by an oscillator 61, which is fed by a driver stage 62. The entire arrangement is located on a conductive base plate 63.
  • the receiver illustrated in FIG. 21 contains a planar antenna 64, which is identical to antenna 60.
  • the output signal of the antenna is fed to a microwave receiving module 65 and demodulated here.
  • the resulting low-frequency signal is amplified and further processed in a printed receiver circuit 66, which thus supplies an alarm signal when an intrusion is attempted.
  • the structure of the two antennas 60 and 64 is illustrated in FIG. 22.
  • the antenna is located on an insulating substrate 68, on which a pattern of conductive strips is produced by means of etching technology.
  • Eight strip-shaped antenna elements 70, 71 excite a number of dipoles 69 in such a way that the desired beam characteristics are achieved.
  • the antenna elements 70 are dimensioned such that the combined radiation of the radiation emitted by the dipoles of these antenna elements forms an antenna beam, the maximum of which is perpendicular to the plane of the substrate 68.
  • the antenna elements 71 are dimensioned such that the radiation generated by their dipoles forms an antenna beam which propagates upwards, so that the main part of this antenna beam does not touch the ground.
  • a divider circuit 72 separates the incoming signal in the transmitter into eight equal parts that excite the antenna elements 70 and 71.
  • 72 in the receiver corresponds to a combination circuit which forms the vector sum of the signals which are supplied by the antenna elements 70, 71.
  • the circuit 72 thus sums the signals of the two antenna beams in the receiver.
  • the antenna arrangement 73 is arranged near the ground 74.
  • the lower antenna beam 75 propagates with a zero elevation angle (i.e. beam axis parallel to the ground); as a result, any movement of an intruder near the ground will result in a change in the received signal of this lower antenna beam.
  • the upper antenna beam 76 spreads out at an elevation angle that is greater than half the beam width. As a result, this upper antenna beam does not touch the ground. Since it does not experience any significant ground reflection, there is a smooth, continuous dependence of the received signal strength on the distance.
  • 24, 24a show a further exemplary embodiment of the invention, in which a passive reflector is used to deflect part of the lower antenna beam upwards and in this way to generate the upper antenna beam.
  • the transmitter and receiver each contain a microwave antenna 77, which can be designed as a planar antenna, parabolic antenna or in some other way and which generates an antenna beam 78 which propagates in one direction towards the receiving antenna.
  • a passive reflector 79 made of metallic material is partially arranged in the beam path and reflects part of the antenna beam upwards, so that an antenna beam 80 directed upwards results. If an intruder passes either the lower antenna beam 78 or the upper antenna beam 80, the change in the received signal caused thereby triggers an alarm.
  • the prism 81 is made of dielectric insulating material. Its dimensions are chosen so that the direction of propagation is deflected upwards by the refraction of the microwave radiation in the prism. As shown in FIG. 25, the prism 81 is arranged in front of a transmitting antenna 82, the beam axis of which points in the direction of the corresponding antenna in the receiver. The radiation incident on the prism 81 is refracted upward and forms the upper antenna beam 83, which does not touch the floor, while the lower antenna beam 84 hits the floor 85 in the manner explained.
  • FIG. 26 illustrates the function of the prism 81.
  • the radiation 86 coming from the transmitting antenna is deflected upward by the prism 81 by an angle of refraction a and forms the upper antenna beam 87.
  • Another way to generate one or more upper antenna beams is to use a Fresnel lens in the lower antenna beam.
  • a Fresnel lens contains a number of stages in a dielectric insulating medium. An incoming microwave passes through this Fresnel lens and emits at a number of different angles, which is determined by the interference pattern between the waves passing through the slit parts and the non-slotted main areas.
  • the Fresnel lens 88 is arranged in the main beam 91 of the transmission antenna 89.
  • the lens 88 generates a number of antenna beams 90 directed upwards, which form the additional height protection zone of the microwave barrier according to the invention.
  • the Fresnel lens 88 is shown in detail in FIG. 28. It contains a block of dielectric insulating material that has a number of slots 92. The depth of the slots 91, the relative dielectric constant of the dielectric material and the spacing of the slots determine the angles of propagation of the outgoing radiation for a predetermined frequency.
  • the lens 88 is wedge-shaped so that the incoming radiation is first refracted upwards before it passes through the slots 92. This ensures that the antenna beams emitted by the Fresnel lens mainly spread obliquely upwards.
  • FIG. 29 shows an embodiment in which a diffraction grating is used to generate a number of antenna beams emitted at different angles from a single incoming antenna beam.
  • the principle corresponds essentially to that of the Fresnel lens explained.
  • the diffraction grating is arranged in front of the antennas that send and receive the lower antenna beam.
  • the incoming radiation is divided into a number of antenna beams, which mainly spread obliquely upwards and thus ensure improved height protection.
  • the diffraction grating shown in FIG. 29 contains a block 93 of dielectric insulating material, on which a number of metallized strips 94 are provided. The position and width of these strips determine the directions of the outgoing antenna beams.
  • the diffraction grating is manufactured in a wedge shape, so that the incoming radiation is first refracted upwards before scattering on the metallic strips 94.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Burglar Alarm Systems (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Waveguide Aerials (AREA)
EP84109376A 1983-10-07 1984-08-08 Mikrowellenschranke Expired EP0139920B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3336610 1983-10-07
DE19833336610 DE3336610A1 (de) 1983-10-07 1983-10-07 Mikrowellenschranke

Publications (2)

Publication Number Publication Date
EP0139920A1 EP0139920A1 (de) 1985-05-08
EP0139920B1 true EP0139920B1 (de) 1987-11-19

Family

ID=6211311

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84109376A Expired EP0139920B1 (de) 1983-10-07 1984-08-08 Mikrowellenschranke

Country Status (3)

Country Link
EP (1) EP0139920B1 (enrdf_load_stackoverflow)
JP (1) JPS6097285A (enrdf_load_stackoverflow)
DE (2) DE3336610A1 (enrdf_load_stackoverflow)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19520891A1 (de) * 1995-06-08 1996-12-12 Abb Patent Gmbh Anordnung mit Emissionsgradstruktur im Infrarotbereich
US7902979B2 (en) * 2008-04-11 2011-03-08 Raytheon Company Directed energy beam virtual fence
JP5339423B2 (ja) * 2008-10-17 2013-11-13 日本信号株式会社 レーダ装置
DE102013107696B4 (de) * 2013-07-18 2020-03-05 Sick Ag Mikrowellenschranke
JP6718651B2 (ja) * 2017-08-21 2020-07-08 株式会社パル技研 環境変化対応センサ

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3016531A (en) * 1955-03-14 1962-01-09 Sperry Rand Corp Antenna distribution system
NL230802A (enrdf_load_stackoverflow) * 1957-09-16
US3093826A (en) * 1960-04-08 1963-06-11 Litton Systems Inc Antenna system
FR1286762A (fr) * 1961-01-24 1962-03-09 Csf Système d'antennes pouvant permettre une émission sur plusieurs faisceaux
US3277480A (en) * 1963-07-16 1966-10-04 Richard K Gardner Simultaneous matrix lobing antenna
US3300768A (en) * 1963-08-20 1967-01-24 Boeing Co Radiant energy type intrusion alarm system
GB1254571A (en) * 1968-11-27 1971-11-24 Theodore Hafner Improvements in or relating to the detection of objects in an electro-magnetic field
FR2125182B1 (enrdf_load_stackoverflow) * 1971-02-17 1975-10-10 Snecma
FR2231062B1 (enrdf_load_stackoverflow) * 1973-05-22 1977-11-10 Tacussel Maurice
US3877002A (en) * 1973-05-25 1975-04-08 Omni Spectra Inc Intrusion detecting system
GB1475111A (en) * 1974-01-23 1977-06-01 Microwave & Electronic Syst Intrusion sensor
GB1529361A (en) * 1975-02-17 1978-10-18 Secr Defence Stripline antenna arrays
DE2806448C2 (de) * 1978-02-15 1985-01-10 Brown, Boveri & Cie Ag, 6800 Mannheim System zur Objektsicherung und zum Personenschutz mittels einer Mikrowellenschranke
GB2107936B (en) * 1981-10-19 1985-07-24 Philips Electronic Associated Antenna

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JPS6097285A (ja) 1985-05-31
DE3467647D1 (en) 1987-12-23
EP0139920A1 (de) 1985-05-08
DE3336610A1 (de) 1985-04-25
JPH0239835B2 (enrdf_load_stackoverflow) 1990-09-07

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