WO1997043662A1 - Event detection device with reduced blind zone - Google Patents

Event detection device with reduced blind zone Download PDF

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Publication number
WO1997043662A1
WO1997043662A1 PCT/GB1997/001264 GB9701264W WO9743662A1 WO 1997043662 A1 WO1997043662 A1 WO 1997043662A1 GB 9701264 W GB9701264 W GB 9701264W WO 9743662 A1 WO9743662 A1 WO 9743662A1
Authority
WO
WIPO (PCT)
Prior art keywords
microwave
antenna
radiation
detection device
event detection
Prior art date
Application number
PCT/GB1997/001264
Other languages
French (fr)
Inventor
Matthew Whitehead
John Konstandelos
Original Assignee
Pyronix Limited
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 Pyronix Limited filed Critical Pyronix Limited
Priority to AU27086/97A priority Critical patent/AU2708697A/en
Priority to IL12694197A priority patent/IL126941A0/en
Publication of WO1997043662A1 publication Critical patent/WO1997043662A1/en

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/50—Systems of measurement based on relative movement of target
    • G01S13/52—Discriminating between fixed and moving objects or between objects moving at different speeds
    • G01S13/56—Discriminating between fixed and moving objects or between objects moving at different speeds for presence detection
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
    • H01Q19/005—Patch antenna using one or more coplanar parasitic elements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/86—Combinations of radar systems with non-radar systems, e.g. sonar, direction finder

Definitions

  • This invention relates to event detection devices and more particularly to an event detection device having an enhanced coverage.
  • Event detection devices for example, intrusion monitoring devices, are well known in the art. Typically they are used to detect unauthorised entry or intrusion in to a protected space.
  • Passive intrusion monitoring devices can, for example, comprise a sensor which detects infra red radiation propagated by warm blooded animals.
  • passive devices comprise a thermal detection device, consisting of one or more thermal detectors adapted to detect infra red radiation incident thereon, and an optical system for directing incident radiation from a plurality of angular fields of view towards the thermal detection device.
  • Such optical systems may consist of lenses, particularly Fresnel lenses and/or reflecting surfaces such as mirrors. Normally such devices are activated when a source of infra red radiation passes from one angular sector to the next.
  • Typical prior art intrusion monitoring devices are illustrated in US patents nos 3703718 and 3958118, and in UK patent no GB1335410. The entire disclosures of these patents are incorporated herein by reference for all purposes.
  • Active intrusion monitoring devices comprise a transmitter and a receiver, the transmitter emitting radiation at a defined frequency and the receiver measuring the Doppler shift in any reflected radiation.
  • Such active devices can, for example, operate at microwave frequencies, using a microwave radiation detection device to detect the reflected radiation.
  • an electrical circuit is provided to process the electrical output signal of the detection device and to compare that signal with a pre-set threshold signal.
  • Microwave intrusion detection devices can be used alone, or as a combined technology event detection device. Examples of such combined devices including specifically a combination of a photo electric sensor and a microwave sensor are described in US patents nos 3725888, 4401976, 4710750, 4833450, 4660024, 5216410, in EP-A-0337964, EP-A-0255812, EP-A-0259015 and in W095/28692. The entire disclosures of all these patents are incorporated herein by reference for all purposes.
  • the outputs of two independent sensing means are supplied to an AND gate, and if both sensing means register an event within a specified period of time, then an alarm is triggered. In this manner, the incidence of false alarms occurring when only a single sensor means is used can be greatly reduced.
  • a problem with single or combined technology event detection devices incorporating microwave radiation detection devices is that of so called "blind zones".
  • the antenna pattern of a microwave motion detector is required to fill a volume of space into which any encroachment by an intruder would result in an alarm condition.
  • Planar antennas for example, printed antennas such as microstrip antennas, tend to have blind zones at angles close to the plane of the antenna in which coverage is often inadequate.
  • Aperture antennas for example, horn antennas and open-ended waveguides, can also have this deficiency.
  • Wire antennas can also exhibit nulls in the antenna pattern in certain directions. The system may thus be unable to detect an intruder in certain regions, in particular creeping below the detector, or approaching from below with the aim of masking the detector.
  • FIG. 1 of the accompanying Drawings shows in side elevation a typical radiated antenna pattern 2 from a wall-mounted microwave radiation detection device 1.
  • a typical radiated antenna pattern 2 from a wall-mounted microwave radiation detection device 1.
  • Such devices are normally mounted high up on a wall 3 in order to be relatively inaccessible, and to give the widest possible area of coverage. It will be observed, however, that the space immediately below the detection device is a blind zone 4 in which the level of microwave radiation is very low and within which an event, such as the presence of an intruder, can remain undetected.
  • the present invention provides an event detection device incorporating a microwave radiation detection device in which the microwave radiation pattern is shaped to provide enhanced coverage.
  • the present invention provides an event detection device which comprises a microwave transmitter and a microwave receiver, the transmitter emitting microwave radiation at a defined frequency and the receiver measuring the Doppler shift in reflected radiation, the device being provided with antenna pattern shaping means whereby the coverage of the device is enhanced.
  • the event detection device of the present invention is preferably a combined technology event detection device, and more particularly a combined event detection device comprising a Doppler shift microwave sensor and a passive infra red sensor.
  • a combined event detection device comprising a Doppler shift microwave sensor and a passive infra red sensor.
  • Examples of such devices are those sold by Pyronix Limited under the trade mark EQUINOX.
  • More than two sensing means may be used where necessary or desired, provided that at least one of the sensing means is a Doppler shift microwave sensor.
  • the antenna pattern shaping means can take a variety of forms.
  • the antenna pattern shaping means can comprise a radiation blocking means which is situated in the near field of the antenna and which causes the radiation pattern to be distorted or defocused, by altering the aperture amplitude and/or phase distributions.
  • the blocking means can, for example, comprise a strip or patch of material, which can be, for example, a conducting material such as copper or other metallic materials, and/or a microwave absorbing material and/or any other material which disturbs the electromagnetic fields.
  • the strip or patch can be positioned in front of the antenna, changing the effective aperture.
  • the blocking means is preferably disposed in an offset position with respect to the aperture, such that the radiation pattern is distorted and spread, increasing coverage in the desired direction(s).
  • the blocking means can be of any suitable size, shape and thickness, although rectangular patches or strips of relatively thin material such as foil are usually preferred.
  • the antenna pattern shaping means can comprise a parasitic antenna which is disposed in the radiated field of the antenna.
  • the parasitic antenna can be formed from a suitable electrically conductive, metallic material and can be positioned such that the field radiated by the parasitic antenna combines with the field radiated by the main antenna to give the required shaping of the main field and enhance the desired coverage thereof.
  • the antenna pattern shaping means comprises a blocking means or a parasitic antenna
  • the strip or patch comprising the blocking means, or the parasitic antenna can be disposed on a surface of the case or cover of the device in the appropriate location relative to the main antenna.
  • the strip or patch blocking means can, for example, be disposed on an inner or outer surface of the case, for example, using a suitable adhesive.
  • the antenna may comprise a plurality of microwave radiation emitting elements disposed in an phased array
  • the pattern shaping means may comprise means for feeding signals to a plurality of the elements in the appropriate amplitude and phase relationships.
  • the radiating elements will be arranged in a square, rectangular, or triangular pattern.
  • the radiating elements By applying an appropriate amplitude and phase weighting to the radiating elements it may be possible to shape the resultant microwave field and enhance the coverage in desired areas. This could be achieved, for example, by varying the path length of the feed line to each element, and by using a different line width to one or more of the elements.
  • reflectors may be used to re-direct a portion of the radiated energy into the blind zone.
  • the event detection device of the invention can also comprise a fault monitoring system in accordance with International patent application no. W095/28693, or an anti-masking system in accordance with UK patent application no. GB9526004.8, the entire disclosures of which are incorporated herein by reference for all purposes. Description of Drawings
  • FIGS. 2(a) and (b) show respectively, in diagrammatic form, a microwave antenna and blocking means for an event detection device according to the invention.
  • Figure 3 illustrates graphically the radiation pattern of the antenna of Figure 1, demonstrating the enhanced coverage obtained using a blocking means in accordance with the invention.
  • the antenna 10 has microstrip radiating elements 20 arranged in a square configuration.
  • the antenna aperture is 50mm by 50mm.
  • a strip of copper foil 30 is disposed in front of the antenna aperture so that it blocks an upper portion of the emitted radiation.
  • the copper strip has a length of 45mm, a width of 4mm, and a thickness of 0.1mm.
  • the strip is arranged at a distance of 4mm from the surface of the radiating elements 20.
  • Figure 3 is a plot of the antenna radiation pattern. As can be seen from the plot, the presence of the blocking strip provides enhanced microwave amplitude at low incident angles, thereby effectively reducing the blind zone beneath the transmitter. The very small decrease in amplitude in the main beam of the antenna is insignificant compared to the improvement in low angle coverage.

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

An event detection device which comprises a microwave transmitter and a microwave receiver, the transmitter emitting microwave radiation at a defined frequency and the receiver measuring the Doppler shift in reflected radiation, the device being provided with antenna pattern shaping means whereby the coverage of the device is enhanced.

Description

EVENT DETECTION DEVICE WITH REDUCED BLIND ZONE
Field of the Invention
This invention relates to event detection devices and more particularly to an event detection device having an enhanced coverage.
Background Art
Event detection devices, for example, intrusion monitoring devices, are well known in the art. Typically they are used to detect unauthorised entry or intrusion in to a protected space.
Commercially available intrusion monitoring devices can be either of the passive or active variety. Passive intrusion monitoring devices can, for example, comprise a sensor which detects infra red radiation propagated by warm blooded animals. Typically such passive devices comprise a thermal detection device, consisting of one or more thermal detectors adapted to detect infra red radiation incident thereon, and an optical system for directing incident radiation from a plurality of angular fields of view towards the thermal detection device. Such optical systems may consist of lenses, particularly Fresnel lenses and/or reflecting surfaces such as mirrors. Normally such devices are activated when a source of infra red radiation passes from one angular sector to the next. Typical prior art intrusion monitoring devices are illustrated in US patents nos 3703718 and 3958118, and in UK patent no GB1335410. The entire disclosures of these patents are incorporated herein by reference for all purposes.
Active intrusion monitoring devices are also known which comprise a transmitter and a receiver, the transmitter emitting radiation at a defined frequency and the receiver measuring the Doppler shift in any reflected radiation. Such active devices can, for example, operate at microwave frequencies, using a microwave radiation detection device to detect the reflected radiation.
In each case, an electrical circuit is provided to process the electrical output signal of the detection device and to compare that signal with a pre-set threshold signal.
Microwave intrusion detection devices can be used alone, or as a combined technology event detection device. Examples of such combined devices including specifically a combination of a photo electric sensor and a microwave sensor are described in US patents nos 3725888, 4401976, 4710750, 4833450, 4660024, 5216410, in EP-A-0337964, EP-A-0255812, EP-A-0259015 and in W095/28692. The entire disclosures of all these patents are incorporated herein by reference for all purposes.
In a typical combined technology event detection device, the outputs of two independent sensing means, responding to different physical stimuli, are supplied to an AND gate, and if both sensing means register an event within a specified period of time, then an alarm is triggered. In this manner, the incidence of false alarms occurring when only a single sensor means is used can be greatly reduced.
A problem with single or combined technology event detection devices incorporating microwave radiation detection devices is that of so called "blind zones". The antenna pattern of a microwave motion detector is required to fill a volume of space into which any encroachment by an intruder would result in an alarm condition. Planar antennas, for example, printed antennas such as microstrip antennas, tend to have blind zones at angles close to the plane of the antenna in which coverage is often inadequate. Aperture antennas, for example, horn antennas and open-ended waveguides, can also have this deficiency. Wire antennas can also exhibit nulls in the antenna pattern in certain directions. The system may thus be unable to detect an intruder in certain regions, in particular creeping below the detector, or approaching from below with the aim of masking the detector.
The problem can be illustrated by reference to Figure 1 of the accompanying Drawings, which shows in side elevation a typical radiated antenna pattern 2 from a wall-mounted microwave radiation detection device 1. Such devices are normally mounted high up on a wall 3 in order to be relatively inaccessible, and to give the widest possible area of coverage. It will be observed, however, that the space immediately below the detection device is a blind zone 4 in which the level of microwave radiation is very low and within which an event, such as the presence of an intruder, can remain undetected.
It will be appreciated that the problem of "blind zones" is present in any single or combined technology event detection device in which a microwave radiation detection device is used. This is because even in combined technology event detection devices, it is necessary for both of the sensors to register an event before an alarm signal is triggered.
Summary of the Invention
The present invention provides an event detection device incorporating a microwave radiation detection device in which the microwave radiation pattern is shaped to provide enhanced coverage.
In a first aspect the present invention provides an event detection device which comprises a microwave transmitter and a microwave receiver, the transmitter emitting microwave radiation at a defined frequency and the receiver measuring the Doppler shift in reflected radiation, the device being provided with antenna pattern shaping means whereby the coverage of the device is enhanced.
The event detection device of the present invention is preferably a combined technology event detection device, and more particularly a combined event detection device comprising a Doppler shift microwave sensor and a passive infra red sensor. Examples of such devices are those sold by Pyronix Limited under the trade mark EQUINOX. More than two sensing means may be used where necessary or desired, provided that at least one of the sensing means is a Doppler shift microwave sensor.
The antenna pattern shaping means can take a variety of forms. In its simplest, and most preferred form, the antenna pattern shaping means can comprise a radiation blocking means which is situated in the near field of the antenna and which causes the radiation pattern to be distorted or defocused, by altering the aperture amplitude and/or phase distributions. The blocking means can, for example, comprise a strip or patch of material, which can be, for example, a conducting material such as copper or other metallic materials, and/or a microwave absorbing material and/or any other material which disturbs the electromagnetic fields. The strip or patch can be positioned in front of the antenna, changing the effective aperture. The blocking means is preferably disposed in an offset position with respect to the aperture, such that the radiation pattern is distorted and spread, increasing coverage in the desired direction(s).
It has been found that by a suitable selection of size and type of material for the blocking means the total coverage of the radiation field can remain substantially unaffected whilst the coverage of the blind zone beneath the detection device can be substantially enhanced.
The blocking means can be of any suitable size, shape and thickness, although rectangular patches or strips of relatively thin material such as foil are usually preferred.
In a further embodiment, the antenna pattern shaping means can comprise a parasitic antenna which is disposed in the radiated field of the antenna. The parasitic antenna can be formed from a suitable electrically conductive, metallic material and can be positioned such that the field radiated by the parasitic antenna combines with the field radiated by the main antenna to give the required shaping of the main field and enhance the desired coverage thereof.
Where the antenna pattern shaping means comprises a blocking means or a parasitic antenna, it can be very convenient to arrange for the strip or patch comprising the blocking means, or the parasitic antenna, to be disposed on a surface of the case or cover of the device in the appropriate location relative to the main antenna. The strip or patch blocking means can, for example, be disposed on an inner or outer surface of the case, for example, using a suitable adhesive.
It will be appreciated that more than one blocking means or parasitic antenna could be used if desired or necessary to obtain the required radiation pattern.
In a further embodiment, the antenna may comprise a plurality of microwave radiation emitting elements disposed in an phased array, and the pattern shaping means may comprise means for feeding signals to a plurality of the elements in the appropriate amplitude and phase relationships. Typically, in an array, the radiating elements will be arranged in a square, rectangular, or triangular pattern.
By applying an appropriate amplitude and phase weighting to the radiating elements it may be possible to shape the resultant microwave field and enhance the coverage in desired areas. This could be achieved, for example, by varying the path length of the feed line to each element, and by using a different line width to one or more of the elements.
In a still further embodiment, reflectors may be used to re-direct a portion of the radiated energy into the blind zone.
Whilst parasitic antennas, phased arrays and reflectors can be used, these can be impractical in some circumstances due to size and cost restraints, and a simple blocking means is usually preferred.
The event detection device of the invention can also comprise a fault monitoring system in accordance with International patent application no. W095/28693, or an anti-masking system in accordance with UK patent application no. GB9526004.8, the entire disclosures of which are incorporated herein by reference for all purposes. Description of Drawings
An embodiment of an event detection device according to the invention will now be more particularly described, by way of example only, with reference to the accompanying Drawings in which:
Figures 2(a) and (b) show respectively, in diagrammatic form, a microwave antenna and blocking means for an event detection device according to the invention; and
Figure 3 illustrates graphically the radiation pattern of the antenna of Figure 1, demonstrating the enhanced coverage obtained using a blocking means in accordance with the invention.
Referring firstly to Figure 2, the antenna 10 has microstrip radiating elements 20 arranged in a square configuration. The antenna aperture is 50mm by 50mm. A strip of copper foil 30 is disposed in front of the antenna aperture so that it blocks an upper portion of the emitted radiation. The copper strip has a length of 45mm, a width of 4mm, and a thickness of 0.1mm. The strip is arranged at a distance of 4mm from the surface of the radiating elements 20. The effect of the blocking strip 30 is illustrated in Figure 3 which is a plot of the antenna radiation pattern. As can be seen from the plot, the presence of the blocking strip provides enhanced microwave amplitude at low incident angles, thereby effectively reducing the blind zone beneath the transmitter. The very small decrease in amplitude in the main beam of the antenna is insignificant compared to the improvement in low angle coverage.
The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS.
1. An event detection device which comprises a microwave transmitter and a microwave receiver, the transmitter emitting microwave radiation at a defined frequency and the receiver measuring the Doppler shift in reflected radiation, the device being provided with microwave radiation pattern shaping means whereby the coverage of the device is enhanced.
2. A device according to Claim 1, which comprises a combined technology event detection device.
3. A device according to Claim 1 or 2, which comprises, in combination, a Doppler shift microwave sensor and a passive infra-red sensor.
4. A device according to any of the preceding Claims, in which the antenna pattern shaping means comprises a radiation blocking means which is situated in the near field of the antenna.
5. A device according to Claim 4, which comprises a strip or patch of a conducting material and/or a microwave absorbing material, and/or a material which disturbs the electromagnetic fields.
6. A device according to Claim 5, in which the strip or patch comprises copper foil.
7. A device according to any of Claims 4 to 6, in which the blocking means is disposed in an off-set position with respect to the centre of the aperture of the antenna, such that the radiation pattern is distorted, increasing coverage in a desired direction.
8. A device according to any of Claims 1 to 3, which comprises a main antenna, and in which the antenna radiation pattern shaping means comprises a parasitic antenna which is disposed in the electromagnetic field emitted by the main antenna.
9. A device according to Claim 8, wherein the parasitic antenna is formed from an electrically conductive, metallic material and positioned such that the field radiated by the parasitic antenna combines with the field radiated by the main antenna to give the required shaping of the overall radiation pattern to enhance the desired coverage thereof.
10. A device according to any of Claims 4 to 9, wherein the blocking means, or the parasitic antenna, is disposed on a surface of the case or cover of the device in an appropriate location relative to the main antenna.
11. A device according to Claim 10, in which the strip or patch blocking means is disposed on an inner surface of the case or cover.
12. A device according to any of Claims 1 to 3, wherein the antenna comprises a plurality of microwave radiation emitting elements disposed in a phased array, and the microwave pattern shaping means comprises means for feeding signals to a plurality of the elements in an appropriate amplitude and phase weighting.
13. A device according to Claim 12, in which the means for feeding signals to a plurality of the elements comprises feed lines of varying lengths and widths.
14. A device according to any of Claims 1 to 3, which comprises one or more reflectors which re-direct a portion of the radiated energy from the transmitter into a desired area.
15. An event detection device substantially as hereinbefore described with reference to and as illustrated in the accompanying Drawings.
16. An event detection device substantially as hereinbefore described.
17. A method of enhancing the coverage of an event detection device which comprises a microwave transmitter and a microwave receiver, the transmitter emitting microwave radiation at a defined frequency and the receiver measuring the Doppler shift in reflected radiation, the method comprising disposing a radiation blocking means in the path of the radiation emitted from the transmitter to alter the aperture amplitude and/or phase distribution thereof.
18. A method according to Claim 18, wherein the blocking means is disposed such that the amplitude of the microwave radiation at low incident angles is increased.
19. A method according to Claim 18 or 19 substantially as hereinbefore described.
PCT/GB1997/001264 1996-05-10 1997-05-09 Event detection device with reduced blind zone WO1997043662A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU27086/97A AU2708697A (en) 1996-05-10 1997-05-09 Event detection device with reduced blind zone
IL12694197A IL126941A0 (en) 1996-05-10 1997-05-09 Event detection device with reduced blind zone

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9609798A GB2312992A (en) 1996-05-10 1996-05-10 Doppler microwave event detection device
GB9609798.5 1996-05-10

Publications (1)

Publication Number Publication Date
WO1997043662A1 true WO1997043662A1 (en) 1997-11-20

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PCT/GB1997/001264 WO1997043662A1 (en) 1996-05-10 1997-05-09 Event detection device with reduced blind zone

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AU (1) AU2708697A (en)
GB (1) GB2312992A (en)
IL (1) IL126941A0 (en)
WO (1) WO1997043662A1 (en)

Cited By (4)

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Publication number Priority date Publication date Assignee Title
EP1094546A2 (en) * 1999-10-19 2001-04-25 Nec Corporation Sector beam antenna with scattering component
US8169356B2 (en) 2007-12-31 2012-05-01 Honeywell International Inc. Anti-mask motion sensor
US8618999B2 (en) 2007-11-14 2013-12-31 Honeywell International Inc. Microwave motion sensor with a reflector
CN113611068A (en) * 2021-09-30 2021-11-05 南通围界盾智能科技有限公司 Mobile rapid deployment guard system

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Publication number Priority date Publication date Assignee Title
FR2905023B1 (en) * 2006-08-17 2008-10-10 Rhodanienne D Electronique App DUAL TECHNOLOGY DETECTION DEVICE HAVING AN INFRARED CHANNEL AND A HYPERFREQUENCY CHANNEL GENERATING A DOUBLE DETECTION LOBE.
FR2906895B1 (en) * 2006-10-04 2010-04-16 Renault Sas DEVICE FOR DETECTING AN OBSTACLE AT THE BACK OF A VEHICLE
GB2445592B (en) * 2007-01-12 2012-01-04 E2V Tech Uk Ltd Antenna structure
JP2011027651A (en) * 2009-07-28 2011-02-10 Panasonic Electric Works Co Ltd Human body detection device

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US3911443A (en) * 1973-11-28 1975-10-07 Johnson Service Co Split beam antenna apparatus for developing angularly oriented beams
EP0055420A2 (en) * 1980-12-27 1982-07-07 Nissan Motor Co., Ltd. A shielding arrangement for a radar type ground speed sensor
EP0337964A1 (en) * 1988-04-13 1989-10-18 ELKRON S.p.A. A combined microwave and infra-red detector device, particularly for anti-intrusion systems
EP0376701A2 (en) * 1988-12-27 1990-07-04 Harada Industry Co., Ltd. Flat-plate patch antenna
DE4313395A1 (en) * 1993-04-23 1994-11-10 Hirschmann Richard Gmbh Co Planar antenna

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GB2280558B (en) * 1993-07-31 1998-04-15 Plessey Semiconductors Ltd Doppler microwave sensor

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Publication number Priority date Publication date Assignee Title
US3911443A (en) * 1973-11-28 1975-10-07 Johnson Service Co Split beam antenna apparatus for developing angularly oriented beams
EP0055420A2 (en) * 1980-12-27 1982-07-07 Nissan Motor Co., Ltd. A shielding arrangement for a radar type ground speed sensor
EP0337964A1 (en) * 1988-04-13 1989-10-18 ELKRON S.p.A. A combined microwave and infra-red detector device, particularly for anti-intrusion systems
EP0376701A2 (en) * 1988-12-27 1990-07-04 Harada Industry Co., Ltd. Flat-plate patch antenna
DE4313395A1 (en) * 1993-04-23 1994-11-10 Hirschmann Richard Gmbh Co Planar antenna

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1094546A2 (en) * 1999-10-19 2001-04-25 Nec Corporation Sector beam antenna with scattering component
EP1094546A3 (en) * 1999-10-19 2002-10-09 Nec Corporation Sector beam antenna with scattering component
US8618999B2 (en) 2007-11-14 2013-12-31 Honeywell International Inc. Microwave motion sensor with a reflector
US8169356B2 (en) 2007-12-31 2012-05-01 Honeywell International Inc. Anti-mask motion sensor
CN113611068A (en) * 2021-09-30 2021-11-05 南通围界盾智能科技有限公司 Mobile rapid deployment guard system

Also Published As

Publication number Publication date
AU2708697A (en) 1997-12-05
GB9609798D0 (en) 1996-07-17
GB2312992A (en) 1997-11-12
IL126941A0 (en) 1999-09-22

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