Radar detector

• US 4,280,223 A
• Filed: 09/13/1979
• Issued: 07/21/1981
• Est. Priority Date: 03/14/1977
• Status: Expired due to Term

• Current Assignee: Fox Electronics & Technology Incorporated.
• Original Assignee: Comgeneral Corporation
• Inventors: Roettele, Donald L., Yohpe, William E.
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): Chin, Tommy P.
• Application Number:
  US06/075,016
• Time in Patent Office: 677 Days
• Field of Search: 375/92, 375/93, 375/94, 455/130, 455/131, 455/226-228, 455/324, 455/302, 455/325, 455/328, 455/334, 455/330, 455/347, 455/351, 343/5 R, 343/113 R, 343/18 R, 343/18 E, 343/17.7, 343/785, 343/850, 343/894, 343/18 D
• US Class Current: 375/339
• CPC Class Codes: G01S 7/022 Road traffic radar detectors

Abstract

A compact radar detector incorporates an elongated dielectric antenna, one end of which is coupled to an aligned cylindrical resonant waveguide. The dielectric antenna has cylindrical and tapered portions which cooperate with the waveguide to provide a narrower beam width, high gain and more directivity in comparison to prior art radar detectors. The antenna projects forwardly from a relatively thin rectangular housing which encloses the waveguide and other components in a manner providing for convenient and efficient assembly.

Claims

1. An improved radar detector comprising a housing, an elongated tubular waveguide disposed within said housing, an elongated dielectric antenna having a first tapered portion projecting into said waveguide for matching the impedances of said antenna and said waveguide, said antenna having a second portion projecting outwardly from said housing for collecting radar signals, said second portion of said dielectric antenna includes a first frusto-conical portion and a second frusto-conical portion connected by an elongated substantially cylindrical portion, means for detecting radar signals received within said waveguide, oscillator means, modulator means for receiving a reference signal from said oscillator means and in response modulating the radar signals detected by said detecting means, means for amplifying the signals detected by said detecting means, phase shifter means for receiving the amplified signals from said amplifying means and for shifting the phase of the amplified signals, phase detector means for receiving the reference signal from said oscillator means and the shifted signals from said phase shifter means, and alarm means connected to said phase detector means to produce an alarm signal when the reference and shifted signals received by said phase detector means are synchronous in frequency and have a predetermined phase relation.

2. The radar detector as defined in claim 1 wherein said oscillator means comprise a voltage controlled oscillator, said phase detector means comprise a first quadrature phase detector for detecting a phase relating 90°

between the reference signal from said oscillator means and the shifted signal from said phase shifter means, and a second phase detector for detecting the phase shift in the shifted signal from said phase shifter means and in response supplying a control voltage to said voltage controlled oscillator.

3. A radar detector as defined in claim 1 wherein said housing has an elongated generally rectangular configuration with a length and width substantially greater than its thickness, said tubular waveguide extends longitudinally within said housing, an elongated circuit board extending within said housing substantially parallel to said waveguide, said antenna projects outwardly from one end of said housing, and said alarm means is disposed adjacent the opposite end of said housing.

4. A radar detector as defined in claim 1 wherein said housing includes substantially parallel spaced generally rectangular side walls each having a length and with substantially greater than the housing thickness defined between said side walls, and said means for detecting radar signals comprise a diode extending within said waveguide with an axis disposed at an acute angle relative to said side walls of said housing.

5. An improved radar detector comprising a housing, an elongated tubular waveguide disposed within said housing, an elongated dielectric antenna having a first portion projecting into said waveguide and a second portion projecting outwardly from said waveguide for collecting radar signals, said second portion of said dielectric antenna includes a frusto-conical portion disposed adjacent said waveguide and connected to an elongated substantially cylindrical portion, means for detecting radar signals received within said waveguide, oscillator means, modulator means for receiving a reference signal from said oscillator means and in response modulating the radar signals detected by said detecting means, means for amplifying the signals detected by said detecting means, phase shifter means for receiving the amplified signals from said amplifying means and for shifting the phase of the amplified signals, phase detector means for receiving the reference signal from said oscillator means and the shifted signals from said phase shifter means, and alarm means connected to said phase detector means to produce an alarm signal when the reference and shifted signals received by said phase detector means are synchronous in frequency and have a predetermined phase relation.

6. The radar detector as defined in claim 5 wherein said oscillator means comprise a voltage controlled oscillator, said phase detector means comprise a first quadrature phase detector for detecting a phase relating 90°

between the reference signal from said oscillator means and the shifted signal from said phase shifter means, and a second phase detector for detecting the phase shift in the shifted signal from said phase shifter means and in response supplying a control voltage to said voltage controlled oscillator.

7. An improved radar detector comprising an elongated housing, an elongated generally cylindrical metal waveguide extending longitudinally within said housing and having opposite end portions, an elongated dielectric antenna having a first portion projecting into one said end portion of said waveguide, said antenna having a second portion projecting outwardly from said one end portion of said waveguide for collecting radar signals, a set of metal support members secured to said opposite end portions of said waveguide in electrical conducting relation, an elongated circuit board extending between said support members generally parallel to said waveguide, means for detecting radar signals received within said waveguide, means for amplifying the signals received by said detecting means, alarm means, and circuit means mounted on said circuit board for actuating said alarm means in response to a predetermined amplified signal output from said amplifying means.

8. A radar detector as defined in claim 7 wherein said second portion of said antenna includes a frusto-conical portion projecting outwardly from said support member connected to said one end portion of said waveguide.

9. An improved radar detector comprising a housing, an elongated tubular waveguide disposed within said housing, an elongated dielectric antenna having a first portion projecting into said waveguide, said antenna having a second portion projecting outwardly from said waveguide for collecting radar signals, means for detecting radar signals received within said waveguide, means for amplifying the signals received by said detecting means, phase shifter means connected to receive amplified signals from said amplifying means, phase detector means connected to receive signals from said phase shifter means, means for modulating the radar signals received within said waveguide, oscillator means for supplying a signal to said modulating means and a reference signal to said phase detector means, alarm means connected to produce an alarm signal when the signals received by said phase detector means are synchronous in frequency and have a predetermined phase relation, an elongated circuit board extending generally parallel to said waveguide, and a set of longitudinally spaced support members connected to opposite end portions of said waveguide and supporting said circuit board.

10. An improved radar detector comprising an elongated housing, an elongated tubular metal waveguide extending longitudinally within said housing and having opposite end portions, an elongated dielectric antenna having a first portion projecting into one said end portion of said waveguide, said antenna having a second portion projecting outwardly from said one end portion of said waveguide for collecting radar signals, a set of metal support members secured to said opposite end portions of said waveguide, an elongated circuit board extending between said support members generally parallel to said waveguide, means for detecting radar signals received within said waveguide and including at least one diode extending within said waveguide with an axis disposed at an acute angle relative to said circuit board, means for amplifying the signals received by said detecting means, alarm means, and circuit means mounted on said circuit board for actuating said alarm means in response to a predetermined amplified signal output from said amplifying means.

11. An improved radar detector comprising an elongated housing, an elongated tubular metal waveguide extending longitudinally within said housing and having opposite end portions, an elongated dielectric antenna having a first portion projecting into one said end portion of said waveguide, said antenna having a second portion projecting outwardly from said one end portion of said waveguide for collecting radar signals, a set of metal support members secured to said opposite end portions of said waveguide, an elongated circuit board extending between said support members generally parallel to said waveguide, means for detecting radar signals received within said waveguide and including a set of axially spaced diodes extending laterally into said waveguide, means including a fastener secured to said waveguide between said diodes for retaining said diodes within said waveguide, means for amplifying the signals received by said detecting means, alarm means, and circuit means mounted on said circuit board for actuating said alarm means in response to a predetermined amplified signal output from said amplifying means.