Broadband omnidirectional RF field intensity indicating device

• US 3,947,770 A
• Filed: 07/12/1974
• Issued: 03/30/1976
• Est. Priority Date: 07/12/1974
• Status: Expired due to Term

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Cavanagh, John F., Wolfe, Hugh K., Vaught, Dennis E.
• Primary Examiner(s): Libman, George H.
• Assistant Examiner(s): Hearn, Robert
• Application Number:
  US05/487,940
• Time in Patent Office: 627 Days
• Field of Search: 325/363, 325/364, 325/366, 343/100 ME, 343/855, 343/867, 343/841, 343/842
• US Class Current: 343/703
• CPC Class Codes: G01R 29/0878 Sensors; antennas; probes; detectors wave guide measuring sections G01R1/24
• CPC Class Codes: H01Q 21/245 provided with means for varying the polarisation polarising devices H01Q15/24; tracking by comparing linear polarisation compounds G01S3/146; reducing depolarisation effects H04B7/00; polarisation diversity H04B7/10

Abstract

A device for indicating the intensity of the vertical component of an incnt electromagnetic field independently of the frequency or the direction of the field uses a dual-loop antenna, current transformers and a means for combining voltage signals. The two antenna loops are planar and the planes of the loops are disposed orthogonally to each other. The loops are arranged to intersect at a common central axis, and the loops are thus symmetrically disposed about the axis. When a source of electromagnetic radiation is incident on the antenna, a current is generated in the loops which is then transformed into a voltage and combined to produce an output which is independent of frequency, of the direction of the field, and is thus representative of the total vertical field intensity.

Claims

1. A broadband omnidirectional electromagnetic-field intensity indicating device operating in the 2 MHz to 32 MHz frequency range comprising:

an antenna having two planar conductive loops, the planes of said loops being orthogonally disposed, and said planes intersecting to form an axis about which the loops are symmetrically disposed, wherein an incident electromagnetic field will generate a current in each of the loops;

two current transformers, one connected to each of the loops to convert the current therein to proportional voltage signals;

a square law detector;

a summing square rooter, said square law detector and said summing square rooter combining the voltage signals to provide an output signal independent of the angle of arrival of and the frequency of the incident electromagnetic field, and representative of the total resultant intensity of the field; and

, means for indicating the output signal.

2. A broadband omnidirectional electromagnetic-field intensity indicating device operating in the 2 MHz to 32 MHz frequency range comprising:

an antenna having two planar conductive loops, the planes of said loops being orthogonally disposed, and said planes intersecting to form an axis about which the loops are symmetrically disposed, wherein an incident electromagnetic field will generate a current in each of the loops;

two current transformers, one connected to each of the loops to convert the current therein to proportional voltage signals;

a quad-hybrid wherein the voltage signals are combined to provide an output signal independent of the angle of arrival of and the frequency of the incident electromagnetic field, and representative of the total resultant intensity of the field; and

,

means for indicating the output signal.