Loop antenna array

• US 10,340,598 B2
• Filed: 08/23/2016
• Issued: 07/02/2019
• Est. Priority Date: 01/22/2016
• Status: Active Grant

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Sasaki, Ai-ichiro, Hirata, Akihiko, Morisawa, Fumiharu, Oka, Souichi, Kagami, Osamu
• Primary Examiner(s): Levi, Dameon E
• Assistant Examiner(s): Alkassim, Jr., Ab Salam
• Application Number:
  US15/764,964
• Publication Number:
  US 20180287257A1
• Time in Patent Office: 1,043 Days
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• 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 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• 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
• CPC Class Codes: H01Q 7/04 Screened antennas H01Q7/02, H01Q7/06 take precedence

Abstract

A loop antenna array that can form a linear and clear communication area boundary is provided. The loop antenna array includes two loop antennas. Currents flow through the loop antennas in opposite directions from each other. In other words, viewing in a direction passing through each of the loop antennas, at a timing when a positive voltage is applied to a signal terminal of an alternating-current source, a clockwise current flows through one loop antenna while a counterclockwise current flows through the other loop antenna. Conversely, at a timing when a negative voltage is applied to the signal terminal of the alternating-current source, a counterclockwise current flows through one loop antenna while a clockwise current flows through the other loop antenna.

Claims

1. A plurality of loop antenna arrays, comprising:

a plurality of loop antennas, wherein

the number of the plurality of loop antennas is 2 to the n-th power (n is an integer of 2 or more) and a group of 2 to the (n−

1)-th power of the plurality of loop antennas is a unit loop antenna array;

centers of the plurality of loop antennas are arranged on a same straight line segment;

a direction of a current flowing through a loop antenna positioned at one end side of the same straight line segment in one of the unit loop antenna arrays and a direction of a current flowing through a loop antenna positioned at the one end side in another of the unit loop antenna arrays are opposite from each other;

the plurality of loop antennas comprise two loop antennas through which currents flow in opposite directions from each other, the two loop antennas arranged so that a straight line distance between centers of the two loop antennas is shorter than twice a distance from a center point between the centers to a communication area boundary, which is a magnetic field strength contour that allows a terminal device to communicate, through a point having a distance in a direction passing through the loop antenna; and

the two loop antennas have the same shape while positions of the centers of the two loop antennas are different.

2. The plurality of loop antenna arrays according to claim 1, wherein

the two loop antennas are arranged on the same plane.

3. The plurality of loop antenna arrays according to claim 1, wherein

a sum of magnetic moments of the two loop antennas is zero.

4. The plurality of loop antenna arrays according to claim 1, wherein

the loop antenna array is of any one of a square, a circle, a rectangle, an oval, a sector, a triangle, a semicircle, a spiral, and a helix.

5. The plurality of loop antenna arrays according to claim 1, wherein

in a loop antenna array including adjacent two of the plurality of loop antennas, one loop antenna and the other loop antenna are formed of a continuous conductor wire.