Loop antenna array

• US 10,700,432 B2
• Filed: 09/01/2016
• Issued: 06/30/2020
• Est. Priority Date: 03/15/2016
• Status: Active Grant

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Sasaki, Ai-ichiro, Hirata, Akihiko, Oka, Souichi, Morisawa, Fumiharu, Kagami, Osamu
• Primary Examiner(s): Tran, Hai V
• Assistant Examiner(s): Bouizza, Michael M
• Application Number:
  US16/079,622
• Publication Number:
  US 20190058253A1
• Time in Patent Office: 1,398 Days
• CPC Class Codes: H01Q 21/0075 Stripline fed arrays H01Q21/065 takes precedence
• 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 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: H04B 5/26 using coils
• CPC Class Codes: H04B 5/43 Antennas

Abstract

A loop antenna array capable of forming a clear boundary of a communication area is provided. The loop antenna array includes three loop antennas, in which a direction of a current flowing through the loop antenna arranged in the middle and a direction of a current flowing through each of the loop antennas arranged on both sides of the loop antenna arranged in the middle are opposite from each other, and the sum of magnetic moments of the three loop antennas is zero.

Claims

1. A loop antenna array comprising three loop antennas, wherein

the loop antenna array is used for wireless communication using a magnetic field,

a direction of a current flowing through the loop antenna arranged in a middle and a direction of a current flowing through each of the loop antennas arranged in both sides are opposite from each other,

areas of regions respectively surrounded by the loop antennas are the same, and

the current flowing through the loop antenna arranged in the middle diverges equally and flows into each of the loop antennas arranged in both sides.

2. The loop antenna array according to claim 1, wherein

in a case where an attenuation rate of magnetic field intensity of 80 dB/dec or greater at a position having a predetermined distance from a center of the loop antenna arranged in the middle is required, assuming that the predetermined distance is z while a distance between centers of the adjacent two loop antennas is a, a is set such that z/a≥

1.6.

3. The loop antenna array according to claim 1, wherein

all the loop antennas are arranged on a same plane.

4. The loop antenna array according to claim 1, wherein

a shape of each of the loop antennas is any one of a square, a circle, a rectangle, an oval, a fan shape, a triangle, a semicircle, a spiral, and a helix.

5. The loop antenna array according to claim 1, wherein

all the loop antennas are formed of a continuous conductor.

6. The loop antenna array according to claim 1, wherein

centers of all the loop antennas are arranged linearly.

7. The loop antenna array according to claim 1, wherein

magnitudes of magnetic moments of the loop antennas arranged in both sides are same, and

a magnitude of the magnetic moment of the loop antenna arranged in the middle is twice the magnitude of the magnetic moment of each of the loop antennas arranged in both sides.

8. A loop antenna array, comprising:

nth power of 2 (n is an integer of 1 or greater) loop antenna arrays, wherein for each of the loop antenna arrays;

the loop antenna array comprises three loop antennas,

a direction of a current flowing through the loop antenna arranged in a middle and a direction of a current flowing through each of the loop antennas arranged in both sides are opposite from each other,

areas of regions respectively surrounded by the loop antennas are the same, and

the current flowing through the loop antenna arranged in the middle diverges equally and flows into each of the loop antennas arranged in both sides,

when a group of the (n−

1)th power of 2 loop antenna arrays is a unitary loop antenna array, a direction of the current flowing through the loop antenna arranged on one end in a first unitary loop antenna array and a direction of the current flowing through the loop antenna arranged on a same position as that one end in a second unitary loop antenna array are opposite from each other.

9. A loop antenna array comprising:

at least 2 loop antenna arrays, wherein for each of the loop antenna arrays;

the loop antenna array comprises three loop antennas,

a direction of a current flowing through the loop antenna arranged in a middle and a direction of a current flowing through each of the loop antennas arranged in both sides are opposite from each other,

areas of regions respectively surrounded by the loop antennas are the same, and

the current flowing through the loop antenna arranged in the middle diverges equally and flows into each of the loop antennas arranged in both sides, and

a 5 loop antenna array arranged between two of the at least 2 loop antenna arrays, wherein

current flows through the loop antenna arranged in a middle of the 5 loop antenna array and the loop antennas arranged at a first end and a second end of the 5 loop antenna array in a same direction,

current flows through the loop antenna arranged in the middle of the 5 loop antenna array and the loop antennas arranged at both sides of the loop antenna arranged in the middle in opposite directions,

a magnetic moment of the loop antenna arranged in the middle of the 5 loop antenna array and the loop antennas arranged at both side of the loop antenna arranged in the middle are twice a magnetic moment of each of the loop antennas arranged at the first and second ends of the 5 loop antenna array, and

a direction of the current flowing through the loop antenna arranged at the first end of the 5 loop antenna array and a direction of the current flowing through the loop antenna arranged on a same position as the first end in an adjacent loop antenna array are opposite from each other, and

a direction of the current flowing through the loop antenna arranged at the second end of the 5 loop antenna array and a direction of the current flowing through the loop antenna arranged on a same position as the second end in an adjacent loop antenna array are opposite from each other.