Classifications

• • 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
  • H01Q13/02—Waveguide horns
  • H01Q13/0275—Ridged horns
• • 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
  • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
  • H01Q1/247—Supports; Mounting means by structural association with other equipment or articles with receiving set with frequency mixer, e.g. for direct satellite reception or Doppler radar
• • 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
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
  • G01S7/021—Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals
  • G01S7/022—Road traffic radar detectors
• • 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
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
  • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
  • G01S7/032—Constructional details for solid-state radar subsystems

Definitions

• a horn antenna construction where a substantially rigid -and planar mounting board having upper and lower surfaces has a microstrip board mounted on the upper surface thereof, where the microstrip board has a mixing diode or diodes mounted in association therewith, and a feed strip for the diode or diodes, and having the feed strip located at or near a first edge of the microstrip board on the upper, exposed side thereof.
• a one-piece molded horn element is provided that has an open bottom, an upwardly flared top wall and a pair of side walls, and having a downwardly extending ridge formed on the underside of the top wall.
• the ridge extends rearwardly to the throat of the horn, and extends downwardly at least in the throat area to such an extent that when the molded horn element is secured to the upper side of the mounting board, the bottom edge of the ridge in the throat area is brought into physical and electrical contact with the feed strip; and moreover, the upper surface of the mounting board then forms the bottom wall of the horn.
• Figure 2 is a plan view of a mounting board having a microstrip board thereon, in keeping with the present invention
• Figure 3 is a plan view of the mounting board of Figure 2 having the pressure cast horn of Figure 1 mounted thereto;
• Figure 4 is a sectional view taken in the direction of arrows 4-4 in Figure 3;
• Figure 6 is a diagrammatic view of the mixer portion of the microstrip board and its relationship to the horn. DESCRIPTION OF THE PREFERRED EMBODIMENTS:
• the details of the microstrip board 14 are irrelevant, except to say it has printed or mounted on it — using printed circuit and microstrip technology — circuit components that include certain reactive components for both a local oscillator and a low pass filter, and other circuitry for creating and handling signals at the L.O. and I.F. frequencies which are below the horn frequencies.
• a mixing diode or diodes mounted on the board at a point shown at 30, and having a conductive feed strip formed as part of the conductive circuit elements on the microstrip board, at 32.
• the feed strip 32 is located at or at least near the edge 34 of the microstrip board, on the upper, exposed surface thereof.
• the vertical placement of the ridge 46 — and its height in the throat area 47 is such that it will be brought into both physical and electrical contact with the feed strip 32 on the upper surface of the microstrip board 14.
• the upper surface of the mounting board 12 in the area generally designated at 50, will form the bottom wall of the horn 41, so that the horn is defined by that bottom wall, its side walls 44 and its top wall 42.
• a ground plane is created at least in the area 50 on the upper surface of the mounting board 12, by plating or coating the mounting board with a conductive material.
• a connection is made between the bottom surfaces of the side walls 44 and the conductive upper surface of the mounting board 12, and because at least the inside surfaces of the one piece molded horn element 16 are conductive, an effective ground at the intermediate frequency is assured for the mixing diode through the physical and electrical connection between the ridge 46 in the throat area 47 and the feed strip 32 for the mixing diode.
• the one piece molded horn element 16 it is most conveniently pressure cast from zinc or other appropriate metal; but it may be constructed from such non-conductive materials as an injection molded thermoplastic, which would then n be conductively coated at least on the inner surface.
• Other techniques such as laid-up epoxy and glass fibre construction may be used, particularly at lower frequencies, but dimensional stability is better assured when the element is either injection molded or more particularly when it is pressure cast of metal.
• each of those cavities are defined by having vertically extending walls 56 and an upper wall or cover 58. If the ground plane or conductive coating on the upper surface of the mounting board 12 underlies the bottom edges of the vertically extending walls 56, then there may be mounted into the cavities 52 or 54 local oscillators, such as a first local oscillator mounted on the microstrip board 14 within the cavity 52, and a second local oscillator mounted on the mounting board 12 within the cavity 54, and they will be shielded.
• local oscillators such as a first local oscillator mounted on the microstrip board 14 within the cavity 52, and a second local oscillator mounted on the mounting board 12 within the cavity 54, and they will be shielded.
• the horn 41 (which is now said to be defined by a flat bottom surface 50, a pair of side walls 44 and an upper wall 42 that flares upwardly) has the configuration so defined, there may be some elevation distortion in respect of the microwave energy received and concentrated by the horn. This may be overcome for the most part by the placement of a lens — such as that indicated by ghost lines at 60 in Figure 4 — in front of the horn 41.
• FIG 6 another advantage of the horn construction of the present invention may be realized. That is, because of the physical mounting of the throat 47 of the horn and its ridge 46 with respect to the feed strip 32, the mixing diode may be physically and securely mounted to the microstrip board. This gives rise to the provision for microstrip printed circuit elements that are operable at microwave frequencies, and thereby very effective port isolation of a three port mixer is achieved. Assuming that the horn 41 is essentially dimensioned to operate at the X-band and K-band frequencies (10.525 GHz and 24.150 GHz, respectively) , a mixer can be provided as indicated in Figure 6 — which is set out as exemplary and is not intended to specifically relate to physical details and dimensions.
• a circuit strip 68 is provided; and connection point 30 is defined, as being where a one- quarter wavelength stub 70 for the X-band, and a one- quarter wavelength stub 72 for the K-band, contact the circuit strip 68.
• a pair of mixing diodes 74 which are usually mounted on a mounting stratum in anti-parallel connection, is connected from the end of the feed strip 32 to the connection point 30.
• a pair of elements 76 and 78 are also provided on the microstrip board between the circuit strip 68 and the circuit strip 66; and the elements 76 and 78 function to provide a low pass filter as described hereafter.
• a further pair of matching stubs 80 and 82 are provided somewhere along the length of the feed strip 32, as described hereafter.
• the horn element 16 provides a good ground return for the local oscillator and I.F. frequencies that are present on the microstrip board 14.
• Any energy reflected back to the feed strip from the mixing diode 74 will be cancelled by an out of phase reflection from the matching stubs 80 or 82, when they are properly placed along the length of the feed strip 32.
• the local oscillator frequency may be in the order of 6.0 GHz (more or less), and that the I.F.
• the low pass filter elements 76 and 78 are therefore placed and dimensioned so as to provide a low pass filter of approximately 2.0 GHz. Therefore, there is good isolation of the I.F. signal on the circuit strip 66 from the L.O. port at 64 or the high frequency port at 32. Moreover, because of the virtual short circuit at the X-band and K-band frequencies at the connection point 30, there is further assurance that there will be no leakage of high frequency energy past the connection point 30 into either the L.O. port at circuit strip 64 or the I.F. output port at circuit strip 66.
• the throat between the ridge 46 and either sidewall 44 appears as a reactive impedance at the first L.O. frequency, so that there is no outward radiation of local oscillator frequency from the horn 41, and a return path is provided for the L.O. signal to ground.
• the physical dimensioning is such that there is no outward radiation of I.F. frequency signals from the horn 41, because the horn throat 47 acts as an effective ground at the I.F. frequency.

Landscapes

• Engineering & Computer Science (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Waveguide Aerials (AREA)
• Radar Systems Or Details Thereof (AREA)
• Support Of Aerials (AREA)
• Transceivers (AREA)
• Accessories For Mixers (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=4126893

Family Applications (1)

Country Status (5)

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• 1984
  • 1984-01-06 CA CA000444841A patent/CA1187602A/en not_active Expired
  • 1984-12-21 WO PCT/GB1984/000448 patent/WO1985003170A1/en not_active Application Discontinuation
  • 1984-12-21 AU AU38377/85A patent/AU572953B2/en not_active Expired
  • 1984-12-21 EP EP19850900486 patent/EP0167582A1/en active Pending
  • 1984-12-21 JP JP60500431A patent/JPS61500944A/ja active Granted

Non-Patent Citations (1)

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