Multi-band coil antenna

Abstract

Among existing antennas, there were no (A) coiled antennas capable of transmitting and receiving on three or more amateur bands (amateur radio frequency bands) in the MF and HF bands, and (B) coiled antennas capable of transmitting and receiving on three or more amateur bands in the VHF and UHF bands without a matching circuit. [Solution] In the present invention, antennas A and B are realized by winding the coil with a slight fold back in the same rotation direction, and by optimizing the coil pitch and number of turns.

Description

[Technical field]

[0001] The present invention relates to a coil antenna capable of transmitting and receiving in multiple bands. [Background technology]

[0002] Several coil antennas that can be used in multiple bands have been proposed. For example, Patent Document 1 proposes a receiving antenna consisting of elements for multiple bands, but this antenna is not suitable for transmission. Patent Document 2 proposes a non-uniform helical antenna that can transmit and receive in two bands, but does not show a specific method for enabling transmission and reception in three or more specific bands. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Publication No. 55-072311 [Patent Document 2] Special Publication No. 2001-501412 [Non-patent literature]

[0004] [Non-Patent Document 1] DB Miron, "A study of the CTHA based on analytical models", IEEE Transactions on Antennas and Propagation, (USA), 2001, Vol. 49, No. 8, p. 1130-1137 [Non-Patent Document 2] Pino Zollo, "CTHA Antenna 2nd part", [online], 2006.11.5, [searched 2024.1.6], Internet<URL: https: / / www.qsl.net / zp4kfx / Antenne / CTHA2.html> Summary of the Invention [Problem to be solved by the invention]

[0005] Existing antennas have the (A)MF band and Transmits and receives signals on three or more amateur bands in the HF band (amateur radio frequency bands) Possible Coiled antenna and (B) Without matching circuit VHF band and Transmits and receives on three or more amateur bands in the UHF band Possible There was no coil antenna. [Means for solving the problem]

[0006] The present invention relates to a coil. in the same rotation direction Fold it back a little and change the coil pitch. and By adjusting the number of turns, the antenna A and antenna B This was achieved. Effect of the Invention

[0007] According to the present invention 、 This allows for both miniaturization of the antenna and multi-band operation with three or more bands. B In addition to these advantages, the present invention also has the advantages of reduced weight, longer life, and reduced transmission power loss due to the elimination of the matching circuit. [Brief description of the drawings]

[0008] [Figure 1] 9:1 ​​unbalanced to unbalanced transformer [Diagram 2] Front view of antenna A [Diagram 3] Rear view of Antenna A [Figure 4] Front view of antenna A with a slightly distorted coil [Diagram 5] Front view of antenna B without cover [Figure 6] Front view of covered antenna B with cover removed DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] To reduce loss, the coil is wound around a cylinder made of a low dielectric constant material such as polyethylene. If the coil pitch is small or the coil has a folded section, the coil is wound with coated wire such as enameled wire to prevent short circuits. To prevent the wire from shifting, grooves are carved into the cylinder at equal intervals across the cylinder, and where the wire moves to another groove, the convex parts of the groove are removed.

[0010] In a coil antenna, the resonant frequency can be changed by changing the outer diameter of the cylinder, the thickness of the cylinder, the material of the cylinder, the length of the conductor, the diameter of the conductor, the coil pitch, etc. If the conductor is lengthened or the coil pitch is reduced, the first resonant frequency will be lowered. If the coil pitch is reduced, the interval between the resonant frequencies will also be narrowed, but there is a limit to how far this can be achieved.

[0011] Table 1 shows the frequency and VSWR of an antenna made of polyurethane copper wire with a conductor diameter of 0.5 mm wound 69 times at a pitch of 3 mm around a 10L wide-mouth light-shielding bottle (cylinder) manufactured by Sanplatec Co., Ltd., with an outer diameter of 217 mm. The light grey vertical bars in the table, from left to right, are the amateur radio 1.8MHz band (1.8MHz~1.9125MHz), 3.5MHz band (3.5MHz~3.805MHz), 7MHz band (7MHz~7.2MHz), 10MHz band (10.1MHz~10.15MHz), 14MHz band (14MHz~14.35MHz), 18MHz band (18.068MHz~18.168MHz), 21MHz band (21MHz~21.45MHz), 24MHz band (24.89MHz~24.99MHz), and 28MHz band (28MHz~29.7MHz) (the same applies to Tables 2, 4, and 6 below). In these cases, the VSWR of each resonant frequency is high, and impedance matching is required.

[0012] [Table 1]

[0013] Table 2 shows the 9:1 unbalanced impedance matching for this antenna. -This is a graph of frequency and VSWR when an unbalanced transformer (Figure 1) is connected. In this transformer, the coated wire is wound five times at equal intervals around a Fairlight toroidal core FT-140-43 using a trifilar winding method. In order not to degrade the performance of the transformer, the distance between the transformer and the central conductor of the coaxial connector is made as short as possible. The VSWR of this transformer is less than 1.3 in the range of 1.8MHz to 54MHz (Table 3).

[0014] [Table 2]

[0015] [Table 3]

[0016] As can be seen from Tables 1 and 2, if the first resonant frequency is set to the 1.8 MHz band for amateur radio, the second resonant frequency will be higher than the 3.5 MHz band. Even if the coil is tightly wound, the second resonant frequency will be higher than the 3.5 MHz band.

[0017] In such a case, the coil should be inserted as shown in 6 in Figs. 2 and 3. in the same rotation direction By winding the coil with a small fold back, the second resonant frequency approaches the first resonant frequency. The longer this folded portion (folded coil) is, the closer the second resonant frequency approaches the first resonant frequency. This allows the coil to resonate in the 1.8 MHz and 3.5 MHz bands even if it is wound with a space. and As in Non-Patent Document 2, an antenna consisting of a coil with a main coil and a folded coil of about the same length has been published, but if the folded coil is long, the gain of the antenna Large Therefore, the folded portion is made to have a minimum length necessary to obtain the desired second resonant frequency.

[0018] To tune the third and subsequent resonant frequencies to the desired frequency, the pitch of the main coil is and The number of turns needs to be improved. EXAMPLES

[0019] Figure 2 is a front view of an antenna capable of transmitting and receiving in the amateur radio bands of 1.8 MHz, 3.5 MHz, 7 MHz, 10 MHz, 14 MHz, 18 MHz, 21 MHz, 24 MHz, 28 MHz, and 50 MHz. The main coil (5) is wound 47.625 times and the folded coil (6) is wound 4.437 times with polyurethane copper wire of conductor diameter 0.5 mm in a 10L wide-mouth light-proof bottle (cylinder) manufactured by Sanplatec Co., Ltd. with an outer diameter of 217 mm. The maximum length of the coil is 66.5 mm. The same wire is 330 mm long and has a 9:1 unbalance with the coil. - An unbalanced transformer (Figure 1) is connected. To prevent the wire from shifting, 134 grooves are carved horizontally into the cylinder at 0.5 mm pitch, and where the wire moves to another groove, it is a good idea to remove the protrusions of the groove.

[0020] The pitch on the left side of our coil, from bottom to top, is 2mm, 2mm, 1.5mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1.5mm, 3.5mm, 1mm, 1.5mm, 1mm, 1.5mm, 1mm, 1mm, 1mm, 1.5mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1.5mm, 1mm, 5mm, 1mm, 1mm, 1mm, 1.5mm, 1mm, 1mm, 1mm, 1mm, 1.5mm, 2.5mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm. The pitch on the right side of the coil, from bottom to top, is 2mm, 1.5mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1.5mm, 3.5mm, 1mm, 1.5mm, 1mm, 1.5mm, 1mm, 1mm, 1mm, 1.5mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm, 1mm. Figure 3 is a rear view of the antenna.

[0021] Tables 4 and 5 are graphs of the frequency and VSWR of this antenna. The light gray vertical bars in Table 5 are the 50MHz band (50MHz to 54MHz) for amateur radio (the same applies to Table 7 below). The lowest VSWR points in the amateur bands are 2.256 (1.87MHz), 1.296 (3.50MHz), 1.254 (7.15MHz), 1.446 (10.11MHz), 1.977 (14.07MHz), 7.042 (18.16MHz), 3.060 (21.05MHz), 4.365 (24.89MHz), 1.512 (29.65MHz), and 2.335 (50.00MHz). When transmitting at frequencies with higher VSWR, use an antenna tuner or similar.

[0022] [Table 4]

[0023] [Table 5]

[0024] The above pitch and The number of turns is a value under the above conditions, and needs to be changed depending on the outer diameter of the cylinder, the thickness of the cylinder, the material of the cylinder, the diameter of the conductor wire, the material of the conductor wire, whether or not the conductor wire is coated, the thickness of the conductor wire coating, the material of the conductor wire coating, whether or not an antenna cover is provided, the outer diameter of the antenna cover, the thickness of the antenna cover, the material of the antenna cover, etc.

[0025] If you slightly distort a part of the coil as shown in 7 in Figure 4, the overall VSWR may decrease as shown in Tables 6 and 7. In this case, the lowest VSWR points on the amateur bands are 2.598 (1.87MHz), 1.187 (3.52MHz), 1.236 (7.16MHz), 1.406 (10.10MHz), 1.970 (14.09MHz), 7.262 (18.16MHz), 2.523 (21.22MHz), 3.620 (24.99MHz), 2.288 (29.70MHz), and 1.119 (50.98MHz, 51.01MHz). When transmitting at frequencies with higher VSWR, use an antenna tuner or similar. It takes trial and error to determine which part of the coil should be distorted, in which direction, and to what extent.

[0026] [Table 6]

[0027] [Table 7] EXAMPLES

[0028] Figure 5 is a front view of an uncovered antenna capable of transmitting and receiving in the amateur radio 144MHz, 430MHz, and 1200MHz bands. The main coil (5) is wound 20.4 times around a polypropylene straw (cylinder) with an outer diameter of 12 mm and an inner diameter of 11 mm, using polyurethane copper wire with a conductor diameter of 0.5 mm and a length of 808 mm including the connection. The maximum length of the coil is 121.3 mm. The wire enters the straw from the bottom left of the coil and is connected to the central conductor of the SMA connector with a minimum distance of 6 mm. No matching circuit is required.

[0029] The pitch on the left side of our coil, from bottom to top, is 3.5mm, 3.5mm, 3.5mm, 3.5mm, 3.5mm, 3.5mm, 3.5mm, 3.5mm, 3.5mm, 4mm, 4mm, 4.5mm, 4.5mm, 5mm, 5.5mm, 9.5mm, 12mm, 12mm, 12mm, 12mm.

[0030] Table 8 shows the frequency and VSWR of this antenna. The light grey vertical bars in the table, from left to right, are the amateur radio 144MHz band (144MHz-146MHz), 430MHz band (430MHz-440MHz), and 1200MHz band (1260MHz-1300MHz) (same for Table 9 below). The lowest VSWR points in the amateur bands are 1.662 (145.6MHz), 1.286 (434.5MHz), and 1.161 (1295.8MHz).

[0031] [Table 8]

[0032] The above pitch and The number of turns is a value under the above conditions, and needs to be changed depending on the outer diameter of the cylinder, the thickness of the cylinder, the material of the cylinder, the diameter of the conductor wire, the material of the conductor wire, whether or not the conductor wire is coated, the thickness of the conductor wire coating, the material of the conductor wire coating, etc. EXAMPLES

[0033] Figure 6 is a front view of a covered antenna with the cover removed, capable of transmitting and receiving in the amateur radio 144 MHz, 430 MHz, and 1200 MHz bands. The main coil (5) is wound 19.7 times around a polypropylene straw (cylinder) with an outer diameter of 12 mm and an inner diameter of 11 mm, using polyurethane copper wire with a conductor diameter of 0.5 mm and a length of 785 mm including the connection. The maximum length of the coil is 109 mm. The wire enters the straw from the bottom left of the coil and is connected to the central conductor of the SMA connector with a minimum distance of 6 mm. No matching circuit is required. The cover is a polyvinyl chloride water hose with an outer diameter of 18 mm and an inner diameter of 14 mm, with a polyethylene cap on the top end.

[0034] The pitch on the left side of our coil, from bottom to top, is 3.5mm, 3.5mm, 3.5mm, 3.5mm, 3.5mm, 3.5mm, 3.5mm, 3.5mm, 4.5mm, 5.5mm, 6mm, 6mm, 6mm, 8.5mm, 11.5mm, 13mm, 9mm, 6mm, and 3mm.

[0035] The frequency and VSWR of this antenna are shown in Table 9. The lowest VSWR points on the amateur bands are 1.601 (146.0MHz), 1.538 (434.9MHz), and 1.144 (1291.7MHz).

[0036] [Table 9]

[0037] The above pitch and The number of turns is a value under the above conditions, and needs to be changed depending on the outer diameter of the cylinder, the thickness of the cylinder, the material of the cylinder, the diameter of the conductor wire, the material of the conductor wire, whether or not the conductor wire is coated, the thickness of the conductor wire coating, the material of the conductor wire coating, the outer diameter of the antenna cover, the thickness of the antenna cover, the material of the antenna cover, etc. [Industrial Applicability]

[0038] The antenna of the present invention can be installed even in a small space. Also, it is possible to transmit and receive on three or more amateur bands by simply connecting the antenna of the present invention with a single coaxial cable, without having to install a monoband antenna for each band and connect them with a coaxial cable. [Explanation of symbols]

[0039] 1 Fairlight toroidal core FT-140-43 2. Covered Wire 3. Contact points 4. Cylinder 5 Main coil (solid line) 6 Folded coil (dotted line) 7. Coil distortion 8 To the antenna 9 (shortest distance) to the center conductor of the coaxial connector 10 To the outer conductor of the coaxial connector 11. To Trance 12 To the center conductor of the SMA connector

Claims

1. To provide a coil antenna in which a second resonance frequency is made close to a first resonance frequency without a large decrease in gain by winding the coil while folding it back slightly in the same direction of rotation.

2. As in claim 1, by winding the coil slightly back in the same direction of rotation, or by adjusting the coil pitch and number of turns, a coil-shaped antenna capable of transmitting and receiving in three or more of the amateur radio bands of 1.8 MHz (1.8 MHz to 1.9125 MHz), 3.5 MHz (3.5 MHz to 3.805 MHz), 7 MHz (7 MHz to 7.2 MHz), 10 MHz (10.1 MHz to 10.15 MHz), 14 MHz (14 MHz to 14.35 MHz), 18 MHz (18.068 MHz to 18.168 MHz), 21 MHz (21 MHz to 21.45 MHz), 24 MHz (24.89 MHz to 24.99 MHz), 28 MHz (28 MHz to 29.7 MHz), and 50 MHz (50 MHz to 54 MHz).

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