DETECTOR PROBE FOR MEASUREMENT OF HIGH-FREQUENCY ELLIPTICALLY POLARIZED FIELDS

• US 3,611,382 A
• Filed: 11/12/1969
• Issued: 10/05/1971
• Est. Priority Date: 11/12/1969
• Status: Expired due to Term

• Current Assignee: Reginald I. Gray
• Original Assignee: Reginald I. Gray
• Inventors: Gray, Reginald I.
• Primary Examiner(s): Bennett, Jr., Rodney D.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US04/875,607
• Time in Patent Office: 692 Days
• Field of Search: 343/1PE,703,732,741,743 325/363,67
• US Class Current: 342/362
• CPC Class Codes: G01R 29/0878 Sensors; antennas; probes; detectors wave guide measuring sections G01R1/24
• CPC Class Codes: H01Q 21/24 Combinations of antenna units polarised in different directions for transmitting or receiving circularly and elliptically polarised waves or waves linearly polarised in any direction circularly polarised patch antennas H01Q9/0428; circularly polarised horns H01Q13/0241; cross-polarised horns H01Q13/0258; polarisation converters H01Q15/242; cross-polarised rear feeds H01Q19/136; crossed polarisation dual antenna H01Q25/001
• CPC Class Codes: H01Q 3/08 for varying two co-ordinates of the orientation
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

An electromagnetic probe which is particularly adapted for the measurement of the electric and magnetic vectors of an elliptically polarized field utilizes a hollow shielded loop which has a double load. The loop is mounted in nonmetallic, low perturbation gimbals so that it can take any position in any plane. The loop is rotated through a plurality of angles dictated by the ellipticity at the point at which measurements are taken. Measurements are taken at each required angle. These measurements are then utilized to calculate the intensities of the electric and magnetic vector components of the field.

Claims

1. An electromagnetic probe comprising:

a supporting member; and

a hollow metallic loop rotatably attached to said support, said loop having two insulated slots separated by 180*; and

coupling means mounted across each of the slots; and

measuring means attached to each of said coupling means;

whereby said measuring means measures the voltages across said coupling means when said loop is placed in an electromagnetic field.

2. An electromagnetic probe as in claim 1 wherein said loop is formed from tubular material.

3. An electromagnetic probe as in claim 2 wherein said support comprises:

gimbals in which said loop is mounted for movement in three planes; and

a tripod upon which said gimbals are rotatably mounted.

4. The method of measuring an elliptically polarized electromagnetic field with a circular metallic loop comprising the steps of:

calibrating the circular metallic loop in a known electromagnetic field to determine the sensitivity proportionality constants for the symmetric and antisymmetric modes;

placing the loop at the required points of the field to be measured;

switching the measuring means to either symmetric or antisymmetric mode;

rotating the loop in three dimensions so as to find the plane in which the highest values of both maximum and minimum responses occur;

measuring the maximum and minimum voltages in the elliptical plane thus defined;

repeating the above procedure for nonchosen mode of step 3; and

computing the magnitudes of both E and H elliptical components by means of calibrated probe sensitivity constants.