JP3856741B2 - Electromagnetic coupling type 4-point feed loop antenna and electromagnetic coupling type 3-point feed loop antenna - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a digital radio capable of listening to a digital radio broadcast by receiving radio waves from an artificial satellite (hereinafter also referred to as “satellite waves”) or radio waves on the ground (hereinafter also referred to as “terrestrial waves”). More particularly, the present invention relates to a loop antenna used in a digital radio receiver.
[0002]
[Prior art]
Recently, digital radio receivers that receive radio waves (satellite waves) or terrestrial waves from artificial satellites and can listen to digital radio broadcasts have been developed and put into practical use in the United States. This digital radio receiver is mounted on a mobile station such as an automobile, and can receive radio waves by receiving radio waves having a frequency of about 2.338 GHz. The terrestrial wave is a signal which is retransmitted by linearly polarized waves after the satellite wave is once received by the earth station and then slightly shifted in frequency.
[0003]
In order to receive such a radio wave having a frequency of about 2.338 GHz, it is necessary to install an antenna outside the vehicle. Various antennas having various structures have been proposed. Generally, a cylindrical antenna is used instead of a flat type (flat plate type). This is because wide directivity is achieved by forming the antenna in a cylindrical shape.
[0004]
A loop antenna is known in the art as one of the cylindrical antennas. The loop antenna has a structure in which one conductive wire is wound in a loop around a cylindrical or columnar (hereinafter referred to as “cylindrical”) member. It is known that when the entire circumference of the loop is selected to be near one wavelength, the current distribution becomes sinusoidal and the antenna has directivity in the axial direction.
[0005]
In such a loop antenna, it is necessary to supply power to it, but it is general to supply power at four points. In order to receive circularly polarized waves, feeding is performed at four points having a phase difference of 90 ° from each other. Such a loop antenna that feeds at four points is called a four-point fed loop antenna. In the conventional four-point feed loop antenna, power is directly fed to the loop portion.
[0006]
More specifically, the conventional four-point feeding loop antenna has a cylindrical body formed by rounding a flexible insulating film member around a central axis into a cylindrical shape, and a central axis along the peripheral surface of the cylindrical body. A loop portion formed of a conductor formed in a loop around the loop portion, and four feed lines formed on the peripheral surface of the cylindrical body to feed power to the loop portion at four points. The part and each of the four feeder lines are directly connected.
[0007]
In a four-point feed loop antenna, radio waves received by the loop unit are phase-matched (adjusted) by shifting the phase by a phase shifter (phase shifter) via four feed lines. ) After being synthesized, it is amplified by a low noise amplifier (LNA) and sent to the receiver body. Here, the combination of a four-point feed loop antenna, a phase shifter, and an LNA is called an antenna device.
[0008]
In the above-described conventional example, the case where power is supplied to the loop portion at four points has been described as an example. However, the present invention can also be extended to the case where power is supplied to the loop portion at N (N is an integer of 2 or more). Such a loop antenna that feeds power at the N point is called an N point fed loop antenna. Therefore, in the conventional N-point feed loop antenna, power is directly supplied to the loop portion by directly connecting the loop portion and each of the N feed lines.
[0009]
[Problems to be solved by the invention]
As described above, in the conventional N-point feeding loop antenna, since feeding is directly performed on the loop portion, there is a problem that feeding impedance becomes too high. Therefore, the conventional N-point feed loop antenna has a problem that it is difficult to perform impedance matching.
[0010]
Accordingly, an object of the present invention is to provide an N-point feed loop antenna that can easily perform impedance matching.
[0011]
[Means for Solving the Problems]
  According to the present invention, a cylindrical body (11) formed by rolling a flexible insulating film member (20) into a cylindrical shape around a central axis (O), and the cylindrical body along its peripheral surface A loop portion (12) made of a conductor formed in a loop around the central axis, and to the loop portion4 pointsFormed on the peripheral surface of the cylinder to supply power4Power supply lines (131 to 134, 131A to 134A), and the loop portion and the4Gap between each of the feeder lines (δ₁, Δ₂) And power supply by electromagnetic couplingThe insulating film member (20) has an upper side (20 _U ) And lower side (20 _L ) And the first side (20 _S1 ) And the second side (20 _S2 ), The cylindrical body (11) is formed by connecting the first side and the second side to each other, and the loop portion (12). ) Is formed on one surface of the insulating film member in the vicinity of the upper side, and the cylindrical body is erected and fixed on the main surface (14a) of the circuit board (14). A four-point feeding phase shifter (15) connected to the four feeding lines is formed on the main surface, and the four-point feeding phase shifter (15) is connected to the four feeding lines. It has first to fourth input terminals (151 to 154) and a feeding point (15a) which is an output terminal. The feeding point (15a) has a first distribution line (1501) and a second distribution line. (1502) and the first distribution line and the first λ / 4 transformer (1511). Connected to the first distribution point (1521), connected to the second distribution point (1522) via the second distribution line and the second λ / 4 transformer (1512), and the feeding point The distance from (15a) to the second distribution point (1522) is longer by λ / 2 than the distance from the feeding point (15a) to the first distribution point (1521), and the first distribution point The point (1521) is divided into two parts, the third distribution line (1503) and the fourth distribution line (1504), and via the third distribution line and the third λ / 4 transformer (1513). Connected to the first input terminal (151), connected to the second input terminal (152) via the fourth distribution line and a fourth λ / 4 transformer (1514), and The distance from the distribution point (1521) to the second input terminal (152) is the first distance The second distribution point (1522) is longer than the distance from the distribution point (1521) to the first input terminal (151) by λ / 4, and the second distribution point (1522) has a fifth distribution line (1505) and a sixth distribution line. (1506) and connected to the third input terminal (153) via the fifth distribution line and the fifth λ / 4 transformer (1515), and the sixth distribution line and The distance from the second distribution point (1522) to the fourth input terminal (154) is connected to the fourth input terminal (154) via a sixth λ / 4 transformer (1516). , Longer by λ / 4 than the distance from the second distribution point (1522) to the third input terminal (153)Electromagnetic coupling type4 pointsA feed loop antenna (10, 10A) is obtained.
[0012]
  Further, according to the present invention, the cylindrical body (11) formed by rolling the flexible insulating film member (20) into a cylindrical shape around the central axis (O), and the cylindrical body on its peripheral surface A loop portion (12) made of a conductor formed in a loop shape around the central axis along with three wires formed on the peripheral surface of the cylindrical body to feed power to the loop portion at three points Power supply lines (131 to 133), and a gap (δ between the loop portion and each of the three power supply lines. ₃ ) And power is supplied by electromagnetic coupling, and the insulating film member (20) _U ) And lower side (20 _L ) And the first side (20 _S1 ) And the second side (20 _S2 ), The cylindrical body (11) is formed by connecting the first side and the second side to each other, and the loop portion (12). ) Is formed on one surface of the insulating film member in the vicinity of the upper side, and the cylindrical body (11) is erected and fixed on the main surface (14a) of the circuit board (14). A three-point feeding phase shifter (15A) connected to the three feeding lines is formed on the main surface of the substrate, and the three-point feeding phase shifter (15A) is connected to the three feeding lines. It has first to third input terminals (151 to 153) to be connected and a feeding point (15a) as an output terminal, and the feeding point (15a) includes a main line (1500) and a λ / 4 transformer ( 1511) to the distribution point (1521), the distribution point (1521) The first to third distribution lines (1501 to 1503) are divided into three parts, connected to the first input terminal (151) via the first distribution line (1501), and the second distribution line ( 1502) to the second input terminal (152), to the third input terminal (153) via the third distribution line (1503), and from the distribution point (1521). The distance from the distribution point (1521) to the second input terminal (152) is longer than the distance from the distribution point (1521) to the first input terminal (151) by λ / 3. 3 is an electromagnetically coupled three-point feed loop characterized in that the distance to the input terminal (153) is longer by 2λ / 3 than the distance from the distribution point (1521) to the first input terminal (151). An antenna (10B) is obtained.
[0013]
  In addition,4 or 3Each of the power supply lines (131 to 134 or 131 to 133) extends from the lower side of the insulating film member to the vicinity of the loop portion.4 or 3The gap (δ₁, Δ₃) From the loop section4 or 3Extending toward the lower side along the feeder line4 or 3The electromagnetic coupling wires (171 to 174 or 171 to 173) may be connected.
[0014]
  Instead, the4Each of the feeder lines (131A to 134A) includes a main feeder line portion (131A-1 to 134A-1) extending from the lower side of the insulating film member to the vicinity of the loop portion, and From the tip (131A-1a to 134A-1a) to the loop portion, the gap (δ₂) May be included and the auxiliary power supply line portion (131A-2 to 134A-2) extending in parallel with the loop portion may be included.
[0015]
  Further, a pole antenna extending along the central axis may be further provided.Yes.
[0016]
In addition, the code | symbol in the said parenthesis is attached | subjected in order to make an understanding of this invention easy, and it is only an example, and of course is not limited to these.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
With reference to FIG. 1 thru | or FIG. 3, the electromagnetic coupling type N point feeding loop antenna 10 which concerns on the 1st Embodiment of this invention is demonstrated. The illustrated electromagnetic coupling type N-point feeding loop antenna 10 is an electromagnetic coupling type four-point feeding loop antenna when N is 4.
[0019]
The illustrated electromagnetically coupled four-point feed loop antenna 10 includes a cylindrical body 11 formed by rolling a flexible insulating film member around a central axis O as will be described in detail later, and this cylindrical body. In order to feed power to the loop portion 12 at four points, a loop portion 12 made of a conductor formed in a loop shape around the central axis O along the peripheral surface is formed on the peripheral surface of the cylindrical body 11 on the peripheral surface. The first to fourth feeder lines 131, 132, 133, and 134 are formed. For example, a copper foil is used as the conductor constituting the loop portion 12. Moreover, as a flexible insulating film member which comprises the cylinder 11, plastics, such as a polyimide, are used, for example. The diameter of the cylinder 11 is 20 mm.
[0020]
Here, in the present invention, as shown in FIG. 2, there is a gap (gap) δ between the loop portion 12 and each of the first to fourth feeders 131 to 134.₁Is provided to feed power to the loop 12 by electromagnetic coupling. In the example shown, the gap δ₁Is, for example, 0.4 mm, but is preferably in the range of 0.2 to 0.8 mm.
[0021]
As shown in FIG. 1, one end of the cylinder 11 in the cylinder axis direction is fixed to the circuit board 14. A phase shifter (four-point feeding phase shifter) 15 is formed on the main surface 14 a of the circuit board 14, and a ground conductor pattern (not shown) is formed on the back surface 14 b of the circuit board 14. The first to fourth power supply terminals 131 a to 134 a of the first to fourth power supply lines 131 to 134 are formed by the first to fourth input terminals 151 to 154 of the four-point power supply phase shifter 15 and the solders 161 to 164. Electrically and mechanically connected.
[0022]
Referring to FIG. 3, the insulating film member 20 for forming the cylindrical body 11 has an upper side 20._UAnd the bottom 20_LAnd the first side 20_S1And the second side 20_S2And has a substantially rectangular shape. And the first side 20_S1And second side 20_S2Are connected to each other to form a cylinder 11 as shown in FIG. This first side 20_S1And second side 20_S2The connection is made with, for example, a double-sided adhesive tape or an adhesive.
[0023]
The loop portion 12 has an upper side 20 on one surface of the insulating film member 20._UIt is formed in the vicinity. When the insulating film member 20 is rolled to form the cylindrical body 11, both ends of the loop portion 12 are electrically connected by solder.
[0024]
In the first embodiment, each of the first to fourth power supply lines 131 to 134 includes the lower side 20 of the insulating film member 20._LTo the vicinity of the loop portion 12 and extending in parallel with the central axis O. The loop portion 12 includes gaps δ with respect to the first to fourth feeder lines 131 to 134, respectively.₁The lower side 20 along the first to fourth feeder lines 131 to 134 from the loop portion 12 in a state of being close to each other_LFirst to fourth electromagnetic coupling wires 171, 172, 173, and 174 extending toward are connected. Coupling length L between feed lines 131 to 134 and electromagnetic coupling lines 171 to 174 adjacent to each other₁By changing the frequency characteristic, the frequency characteristics of the electromagnetically coupled four-point feed loop antenna 10 can be changed.
[0025]
The loop portion 12 formed on one surface of the insulating film member 20, the first to fourth feeder lines 131 to 134, and the first to fourth electromagnetic coupling lines 171 to 174 are made of the same conductive material (for example, copper foil). ).
[0026]
Generally, in a four-point feed loop antenna, the feed impedance needs to be 50Ω. In the electromagnetically coupled four-point feed loop antenna 10 according to the present embodiment, the impedance at each of the feed terminals 131a to 134a can be lowered to 15Ω. In the illustrated example, the impedance at each of the power supply terminals 131a to 134a is 60Ω. Thereby, the impedance at the output terminal 15a of the phase shifter (four-point feeding phase shifter) 15 can be 50Ω. In other words, impedance matching can be easily achieved by supplying power to the loop portion 12 by electromagnetic coupling. The gap δ₁The impedance at each of the power supply terminals 131a to 134a can be changed by changing the size of.
[0027]
Next, the four-point power supply phase shifter 15 will be described in detail. The output terminal 15a is called a feeding point. The four-point power supply phase shifter 15 is also called a 90 ° phase shifter.
[0028]
First, how to obtain the phase difference will be described. In the four-point power supply phase shifter 15, it is necessary to delay the phases of the first to fourth input terminals 151 to 154 by λ / 4 (90 °). For this purpose, an electrical distance (hereinafter simply referred to as “distance”) from the first to fourth input terminals 151 to 154 to the feeding point 15a may be considered. That is, it is assumed that the distance from the first input terminal 151 to the feeding point 15a is a predetermined distance. In this case, the distance from the second input terminal 152 to the feeding point 15a is set to a distance obtained by adding λ / 4 to a predetermined distance. The distance from the third input terminal 153 to the feeding point 15a is set to a distance obtained by adding λ / 2 to a predetermined distance. The distance from the fourth input terminal 154 to the feeding point 15a is set to a distance obtained by adding 3λ / 4 to a predetermined distance.
[0029]
With such a configuration, the phase difference of the four-point power supply phase shifter 15 can be satisfied.
[0030]
Next, impedance matching will be described. In the four-point feeding phase shifter 15, the following procedure is taken to match the feeding point 15 a to 50Ω. In the illustrated example, the diameter of the cylindrical body 11 is 20 mm, and the impedance at each of the power supply terminals 131a to 134a is 60Ω. In this example, impedance matching is performed using six λ / 4 transformers described later. The four-point power supply phase shifter 15 is configured by a microstrip line.
[0031]
The 50Ω feeding point 15 a is divided into two parts, the first distribution line 1501 and the second distribution line 1502. The impedance of each of the first and second distribution lines 1501 and 1502 is 100Ω. The feeding point 15 a is connected to the first distribution point 1521 via the first distribution line 1501 and the first λ / 4 transformer 1511. On the other hand, the feeding point 15 a is connected to the second distribution point 1522 via the second distribution line 1502 and the second λ / 4 transformer 1512. The impedance of each of the first and second λ / 4 transformers 1511 and 1512 is 70.1Ω. Further, the distance from the feeding point 15a to the second distribution point 1522 is longer than the distance from the feeding point 15a to the first distribution point 1521 by λ / 2. The impedance of the first and second distribution points 1521 and 1522 is 50Ω.
[0032]
    The first distribution point 1521 is divided into two parts, the third distribution line 1503 and the fourth distribution line 1504. The impedance of each of the third and fourth distribution lines 1503 and 1504 is 100Ω. The first distribution point 1521 is connected to the first input terminal 151 via the third distribution line 1503 and the third λ / 4 transformer 1513. On the other hand, the first distribution point 1521 has a fourth distribution line 1504 and a fourth λ / 4 metamorphosis.vesselIt is connected to the second input terminal 152 through 1514. The impedance of each of the third and fourth λ / 4 transformers 1513 and 1514 is 77.5Ω. Further, the distance from the first distribution point 1521 to the second input terminal 152 is longer than the distance from the first distribution point 1521 to the first input terminal 151 by λ / 4.
[0033]
Similarly, the second distribution point 1522 is divided into two parts, the fifth distribution line 1505 and the sixth distribution line 1506. The impedance of each of the fifth and sixth distribution lines 1505 and 1506 is 100Ω. The second distribution point 1522 is connected to the third input terminal 153 via the fifth distribution line 1505 and the fifth λ / 4 transformer 1515. On the other hand, the second distribution point 1522 is connected to the fourth input terminal 154 via the sixth distribution line 1506 and the sixth λ / 4 transform call 1516. The impedance of each of the fifth and sixth λ / 4 transformers 1515 and 1516 is 77.5Ω. Further, the distance from the second distribution point 1522 to the fourth input terminal 154 is longer than the distance from the second distribution point 1522 to the third input terminal 153 by λ / 4.
[0034]
With such a configuration, impedance matching of the four-point feeding phase shifter 15 can be achieved.
[0035]
On the other hand, in the conventional four-point feed loop antenna having a structure in which the feed lines 131 to 134 are directly connected to the loop portion 12, the impedances at the feed terminals 131a to 134a are too high at 250 to 300Ω. It was. Therefore, it is difficult to perform impedance matching at the output terminal (feeding point) 15a of the phase shifter 15.
[0036]
The electromagnetically coupled four-point feed loop antenna 10 illustrated in FIGS. 1A and 1B is an antenna that can receive only satellite waves.
[0037]
On the other hand, as shown in FIGS. 4A and 4B, by providing the electromagnetically coupled four-point feed loop antenna 10 with a pole antenna 30, it is possible to receive terrestrial waves. That is, the antenna shown in FIGS. 4 (a) and 4 (b) is an antenna device including a loop antenna / monopole antenna in an integrated manner. The pole antenna 30 extends along the central axis O. The upward protruding length of the pole antenna 30 is 1.8 mm.
[0038]
5 and 6, the electromagnetically coupled four-point feed loop antenna 10A according to the second embodiment of the present invention is different in the configuration (structure) of the feed line as will be described later. Except for this, the configuration is the same as that shown in FIGS. Accordingly, reference numerals 131A, 132A, 133A, and 134A are assigned to the first to fourth feeder lines. Components having the same configurations as those shown in FIG. 1 to FIG.
[0039]
The first to fourth power supply lines 131A to 134A are respectively provided on the lower side 20 of the insulating film member 20._LTo the vicinity of the loop portion 12, the first to fourth main power supply line portions 131A-1 to 134A-1 extending in parallel with the central axis O, and the first to fourth main power supply line portions 131A-1 to 131A-1. The gap δ from the tip 131A-1a to 134A-1a of the 134A-1 to the loop portion 12₂The first to fourth sub-feeding line portions 131A-2 to 134A-2 extending in parallel with the loop portion 12 in a state where the space is opened.
[0040]
The coupling length L between each sub-feed line portion 131A-2 to 134A-2 and the loop portion 12₂By changing the frequency characteristics of the electromagnetically coupled four-point feed loop antenna 10A. The gap δ₂The impedance at each of the power supply terminals 131a to 134a can be changed by changing the size of.
[0041]
Even in the electromagnetically coupled four-point feed loop antenna 10A according to the second embodiment, similarly to the electromagnetically coupled four-point fed loop antenna 10 according to the first embodiment described above, the feeding to the loop unit 12 is performed by electromagnetic coupling. Since this is done, the impedance at each of the power supply terminals 131a to 134a can be lowered. Thereby, the impedance at the output terminal (feed point) 15a of the phase shifter (four-point feed phase shifter) 15 can be easily set to 50Ω.
[0042]
With reference to FIG.7 and FIG.8, the electromagnetic coupling type N point feeding loop antenna 10B which concerns on the 3rd Embodiment of this invention is demonstrated. The illustrated electromagnetic coupling type N point feeding loop antenna 10B is an electromagnetic coupling type three point feeding loop antenna when N is three, that is, an electromagnetic coupling type three point feeding loop antenna.
[0043]
The illustrated electromagnetically coupled three-point feed loop antenna 10B includes a cylindrical body 11 formed by rolling a flexible insulating film member around a central axis O into a cylindrical shape, and the cylindrical body 11 along its peripheral surface. A loop portion 12 made of a conductor formed in a loop around the central axis O, and first to first formed on the peripheral surface of the cylindrical body 11 in order to feed power to the loop portion 12 at three points. 3 feed lines 131, 132, 133. For example, a copper foil is used as the conductor constituting the loop portion 12. Moreover, as a flexible insulating film member which comprises the cylinder 11, plastics, such as a polyimide, are used, for example. The diameter of the cylinder 11 is 20 mm.
[0044]
Here, in the present invention, as shown in FIG. 8, there is a gap (gap) δ between the loop portion 12 and each of the first to third feeders 131 to 133._ThreeIs provided to feed power to the loop 12 by electromagnetic coupling. In the example shown, the gap δ_ThreeIs, for example, 0.4 mm, but is preferably in the range of 0.2 to 0.8 mm.
[0045]
As shown in FIG. 7, one end of the cylinder 11 in the cylinder axis direction is fixed to the circuit board 14. A phase shifter (three-point feeding phase shifter) 15 </ b> A is formed on the main surface 14 a of the circuit board 14, and a ground conductor pattern (not shown) is formed on the back surface of the circuit board 14. The first to third feeding terminals 131a to 133a of the first to third feeding lines 131 to 133 are formed by the first to third input terminals 151 to 153 and the solders 161 to 163 of the three-point feeding phase shifter 15A. Electrically and mechanically connected.
[0046]
The loop portion 12 includes gaps δ with respect to the first to third feeders 131 to 133, respectively._ThreeThe first to third electromagnetic coupling wires 171, 172, and 173 extending downward from the loop portion 12 along the first to third feeding lines 131 to 133 are connected in a state of being close to each other with a gap therebetween. Yes. The coupling length L between the feed lines 131 to 133 and the electromagnetic coupling lines 171 to 173 adjacent to each other_ThreeBy changing the frequency characteristic of the electromagnetically coupled three-point feed loop antenna 10B.
[0047]
In a three-point feed loop antenna, the feed impedance needs to be 50Ω. In the electromagnetically coupled three-point feed loop antenna 10B according to the present embodiment, the impedance at each of the feed terminals 131a to 133a can be lowered to 15Ω. In the illustrated example, the impedance at each of the power supply terminals 131a to 133a is 75Ω. Thereby, the impedance at the output terminal 15a of the phase shifter (three-point feeding phase shifter) 15A can be easily set to 50Ω. In other words, impedance matching can be easily achieved by supplying power to the loop portion 12 by electromagnetic coupling. The gap δ_ThreeThe impedance at each of the power supply terminals 131a to 133a can be changed by changing the size of.
[0048]
Next, the three-point power supply phase shifter 15A will be described in detail. The output terminal 15a is called a feeding point. The three-point power supply phase shifter 15A is also called a 120 ° phase shifter.
[0049]
First, how to obtain the phase difference will be described. In the three-point feeding phase shifter 15A, it is necessary to delay the phases of the first to third input terminals 151 to 153 by λ / 3 (120 °). For this purpose, an electrical distance (hereinafter simply referred to as “distance”) from the first to third input terminals 151 to 153 to the feeding point 15a may be considered. That is, it is assumed that the distance from the first input terminal 151 to the feeding point 15a is a predetermined distance. In this case, the distance from the second input terminal 152 to the feeding point 15a is set to a distance obtained by adding λ / 3 to a predetermined distance. The distance from the third input terminal 153 to the feeding point 15a is set to a distance obtained by adding 2λ / 3 to a predetermined distance.
[0050]
With such a configuration, the phase difference of the three-point power supply phase shifter 15A can be satisfied.
[0051]
Next, impedance matching will be described. In the three-point feeding phase shifter 15A, the following procedure is taken to match the feeding point 15a to 50Ω. In the illustrated example, the diameter of the cylinder 11 is 20 mm, and the impedance at each of the power supply terminals 131a to 133a is 75Ω. In this example, impedance matching is performed using one λ / 4 transformer described later. The three-point power supply phase shifter 15A is configured by a microstrip line.
[0052]
The 50Ω feeding point 15 a is connected to the distribution point 1521 via a 50Ω main line 1500 and a λ / 4 transformer 1511. The impedance of the λ / 4 transformer 151 is 35.4Ω. The impedance of the distribution point 1521 is 25Ω.
[0053]
  Three distribution points 1521 are distributed to the first to third distribution lines 1501, 1502, and 1503. The impedance of each of the first to third distribution lines 1501 to 1503 is 75Ω. The distribution point 1521 is connected to the first input terminal 151 via the first distribution line 1501. The distribution point 1521 is connected to the second input terminal 152 through the second distribution line 1502. Further, the distribution point 1521 is connected to the third input terminal 153 via the third distribution line 1503. The distance from the distribution point 1521 to the second input terminal 152 isDistribution pointThe distance from 1521 to the first input terminal 151 is longer by λ / 3. The distance from the distribution point 1521 to the third input terminal 153 isDistribution pointThe distance from 1521 to the first input terminal 151 is longer by 2λ / 3.
[0054]
With such a configuration, impedance matching of the three-point feeding phase shifter 15A can be achieved. The three-point power supply phase shifter 15A has a simpler structure than the four-point power supply phase shifter 15. As a result, it can be seen that the electromagnetically coupled three-point feed loop antenna 10B is easier to miniaturize than the electromagnetically coupled four-point fed loop antennas 10 and 10A.
[0055]
  Although the present invention has been described above with reference to preferred embodiments, it is needless to say that the present invention is not limited to the above-described embodiments. For example, in the above-described embodiment, the power supply lines 131 to 134 (main power supply line parts 131A-1 to 134A-1) and the electromagnetic coupling lines 171 to 174 are the lower side 20 of the insulating film member 20._LHowever, it is of course possible to extend in an oblique direction.The
[0056]
【The invention's effect】
  As is clear from the above description, in the present invention, the loop portion and4 or 3Since a gap is provided between each of the power supply lines and power is supplied to the loop portion by electromagnetic coupling, impedance matching can be easily achieved.
[Brief description of the drawings]
FIG. 1 shows a configuration of an electromagnetically coupled four-point feed loop antenna according to a first embodiment of the present invention, where (a) is a plan view and (b) is a front view.
2 is a perspective view showing an arrangement relationship between a loop portion and four feeding lines that constitute the electromagnetically coupled four-point feeding loop antenna shown in FIG. 1; FIG.
3 is a development view of the electromagnetically coupled four-point feed loop antenna of FIG. 1; FIG.
4 shows a configuration of a composite antenna device in which a pole antenna is further provided to the electromagnetically coupled four-point feeding loop antenna shown in FIG. 1, wherein (a) is a plan view and (b) is a front view.
5A and 5B show a configuration of an electromagnetically coupled four-point feed loop antenna according to a second embodiment of the present invention, where FIG. 5A is a plan view and FIG. 5B is a front view.
6 is a development view of the electromagnetically coupled four-point feed loop antenna of FIG. 5. FIG.
FIG. 7 is a plan view showing a configuration of an electromagnetically coupled three-point feed loop antenna according to a third embodiment of the present invention.
8 is a perspective view showing an arrangement relationship between a loop portion and three feeding lines that constitute the electromagnetically coupled three-point feeding loop antenna shown in FIG. 7;
[Explanation of symbols]
10, 10A Electromagnetic coupling type 4-point feeding loop antenna
10B Electromagnetically coupled three-point feed loop antenna
11 cylinder
12 Loop part
131-134 Feed line
131A to 134A Power supply line
131A-1 to 134A-1 Main feeder line part
131A-2 to 134A-2 Sub-feed line section
14 Circuit board
15 Phase shifter (4-point feeding phase shifter)
15A 3-point feeding phase shifter
161-164 Solder
171 to 174 Electromagnetic coupling wire
20 Insulating film member

Claims (6)

A cylindrical body formed by rolling a flexible insulating film member around a central axis into a cylindrical shape, and a conductor formed in a loop around the central axis along the peripheral surface of the cylindrical body In order to supply power to the loop portion at four points , the cylindrical body has four power supply lines formed on the peripheral surface, and each of the loop portion and the four power supply lines A gap between the
The insulating film member has a substantially rectangular shape having an upper side, a lower side, a first side, and a second side, and the first side and the second side are The cylinder is formed by connecting each other,
The loop portion is formed in the vicinity of the upper side on one surface of the insulating film member,
The cylindrical body is erected and fixed on the main surface of the circuit board, and a four-point power supply phase shifter connected to the four power supply lines is formed on the main surface of the circuit board. And
The four-point feeding phase shifter has first to fourth input terminals connected to the four feeding lines and a feeding point that is an output terminal.
The feeding point is divided into two parts, a first distribution line and a second distribution line, and is connected to the first distribution point via the first distribution line and the first λ / 4 transformer, The second distribution point and the second λ / 4 transformer are connected to the second distribution point, and the distance from the power supply point to the second distribution point is the first distribution from the power supply point. Λ / 2 longer than the distance to the point,
The first distribution point is divided into two parts, a third distribution line and a fourth distribution line, and is supplied to the first input terminal via the third distribution line and a third λ / 4 transformer. Connected to the second input terminal via the fourth distribution line and a fourth λ / 4 transformer, and the distance from the first distribution point to the second input terminal is Longer by λ / 4 than the distance from the first distribution point to the first input terminal,
The second distribution point is divided into two parts, a fifth distribution line and a sixth distribution line, and is supplied to the third input terminal via the fifth distribution line and a fifth λ / 4 transformer. Connected to the fourth input terminal via the sixth distribution line and a sixth λ / 4 transformer, and the distance from the second distribution point to the fourth input terminal is An electromagnetically coupled four-point feed loop antenna characterized by being longer by λ / 4 than a distance from a second distribution point to the third input terminal . Each of the four feeding lines extends from the lower side of the insulating film member to the vicinity of the loop portion,
In the loop portion, four electromagnetic waves extending from the loop portion along the four feed lines toward the lower side with respect to the four feed lines with the gap being provided, respectively. wherein the bond line is connected, electromagnetic coupling type four-point feeding loop antenna according to claim 1, wherein. Each of the four feeder lines includes a main feeder line portion extending from the lower side of the insulating film member to the vicinity of the loop portion, and the gap from the tip of the main feeder line portion to the loop portion. wherein the state where drilled with a sub power supply line portion extending parallel to the loop portion, claim 1 electromagnetic coupling type four-point feeding loop antenna according. The electromagnetically coupled four-point feed loop antenna according to claim 1, further comprising a pole antenna extending along the central axis. A cylindrical body formed by rolling a flexible insulating film member around a central axis into a cylindrical shape, and a conductor formed in a loop around the central axis along the peripheral surface of the cylindrical body In order to supply power to the loop portion at three points, the cylindrical body has three power supply lines formed on the peripheral surface, and each of the loop portion and the three power supply lines A gap between the
The insulating film member has a substantially rectangular shape having an upper side, a lower side, a first side, and a second side, and the first side and the second side are The cylinder is formed by connecting each other,
The loop portion is formed in the vicinity of the upper side on one surface of the insulating film member,
The cylindrical body is erected and fixed on the main surface of the circuit board, and on the main surface of the circuit board. Is formed with a three-point feeding phase shifter connected to the three feeding lines,
The three-point feeding phase shifter has first to third input terminals connected to the three feeding lines, and a feeding point that is an output terminal.
The feed point is connected to a distribution point via a main line and a λ / 4 transformer,
The distribution points are divided into three distributions of first to third distribution lines, connected to the first input terminal via the first distribution line, and the second distribution line via the second distribution line. Connected to the input terminal, connected to the third input terminal via the third distribution line, and the distance from the distribution point to the second input terminal is the first input terminal from the distribution point The distance from the distribution point to the third input terminal is longer by 2λ / 3 than the distance from the distribution point to the first input terminal. An electromagnetically coupled three-point feed loop antenna. Each of the three feed lines extends from the lower side of the insulating film member to the vicinity of the loop portion,
The loop portion includes three electromagnetic waves extending from the loop portion along the three power supply lines toward the lower side with the gap between the three power supply lines. 6. The electromagnetically coupled three-point feed loop antenna according to claim 5, wherein a coupling line is connected.

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