Monopole electrically small antenna with long-wave frequency band

Abstract

The invention discloses a monopole electrically small antenna with a long-wave frequency band. The monopole electrically small antenna comprises a sleeve capacitor structure, a spiral coil and a bottom metal floor. The sleeve capacitor structure comprises a solid metal column, a first metal plate, a hollow metal sleeve and a second metal plate. Wherein the hollow metal sleeve and the solid metal column are coaxially arranged, and the hollow metal sleeve and the solid metal column do not make contact with each other; the top end of the solid metal column is connected with the center of the bottom surface of the first metal plate; the top end of the hollow metal sleeve is connected with the second metal plate; the first metal plate and the second metal plate are not in contact with each other; the bottom end of the solid metal column is connected with the bottom metal floor; and a gap is reserved between the bottom end of the hollow metal sleeve and the bottom metal floor. The spiral coil is distributed around the sleeve capacitor structure, and the two ends of the spiral coil are connected with the second metal plate of the sleeve capacitor structure and the bottom metal floor respectively. According to the invention, the miniaturization of the monopole electrically small antenna with a long-wave frequency band is realized.

Description

Technical Field

[0001] The present invention relates to a radio frequency antenna, in particular to a monopole electric small antenna. Background Art

[0002] A monopole antenna is typically one with a maximum dimension less than 1 / 2π or 1 / 10 of the operating wavelength. It is typically mounted vertically or horizontally on the ground or a conductive surface. Assuming the ground is a perfect conductor, the monopole antenna is equivalent to a symmetrical dipole. This equivalence only holds true in the upper half-space of the ground or conductor. Its operating principle is to transmit and receive electromagnetic waves by forming a virtual ground plane between the conductor and the ground. When an alternating current is applied to the monopole antenna, an oscillating current is generated between the conductor and the virtual ground plane, causing electromagnetic waves to radiate. The ground acting as a reflector enhances the antenna's performance, resulting in radiation characteristics similar to those of a complete dipole antenna.

[0003] The radiation pattern of a monopole antenna is circular in the horizontal plane and omnidirectional, providing uniform radiation and reception throughout 360 degrees. In the vertical plane, the radiation pattern exhibits a dual-lobed pattern, with one lobe above and one below. Monopole antennas have high impedance, which is generally a function of their length, requiring appropriate matching techniques to match the transmission line.

[0004] Longwave electromagnetic waves, due to their low surface wave propagation attenuation (capable of beyond-line-of-sight transmission) and strong dielectric penetration (able to penetrate seawater, soil, and rock formations), are irreplaceable in underwater submersible communications, underground resource exploration, long-range navigation, and emergency beacons. However, the wavelengths corresponding to this frequency band are often as long as a kilometer, and traditional resonant antennas (such as monopoles and dipoles) must meet physical dimensions of a quarter or half wavelength. This kilometer-scale dimension makes it difficult to integrate antennas into mobile platforms such as ships, vehicles, and aircraft, or into portable devices, severely limiting their application scenarios.

[0005] The existing long-wave frequency band monopole electrically small antennas, such as the top-loaded umbrella monopole, may have an actual length of 10 to 100 meters even if the size is λ / 100. Summary of the Invention

[0006] Purpose of the invention: In view of the above-mentioned existing technologies, a monopole electrically small antenna in the long-wave frequency band is proposed to break through the size limitation and realize the miniaturization of the antenna.

[0007] Technical solution: A long-wave frequency band monopole electric small antenna, characterized by comprising a sleeve capacitor structure, a spiral coil, and a bottom metal floor; The sleeve capacitor structure includes a solid metal column and a first metal plate, a hollow metal sleeve and a second metal plate; wherein the hollow metal sleeve is coaxially arranged with the solid metal column and does not contact the solid metal column; the first metal plate is located directly above the second metal plate; the top end of the solid metal column passes through the second metal plate and is connected to the center of the bottom surface of the first metal plate; the top end of the hollow metal sleeve is connected to the second metal plate; the bottom end of the solid metal column is connected to the bottom metal floor; and a gap is left between the bottom end of the hollow metal sleeve and the bottom metal floor. The spiral coil is symmetrically distributed around the sleeve capacitor structure, and two ends of the spiral coil are respectively connected to the second metal plate and the bottom metal floor of the sleeve capacitor structure.

[0008] Among them, the structure of the hollow metal sleeve and the solid metal column can achieve a larger equivalent capacitance in a smaller size, meeting the design requirements of antenna miniaturization and high power input.

[0009] The spiral coil design can effectively reduce the heat loss of long wires and achieve a higher equivalent inductance value within a limited size, meeting the design requirements of antenna miniaturization.

[0010] Depending on different application scenarios and usage requirements, the spacing between coils is not limited to being equidistant, and the radius of each coil is not limited to being equal.

[0011] The sleeve capacitor structure is connected to the spiral coil structure through the second metal plate and is connected in parallel with the spiral coil structure equivalent to an inductor to form an LC resonant circuit.

[0012] Beneficial effects: 1) The operating frequency band of the monopole electric small antenna of the present invention is the long-wave frequency band, and it has strong dielectric penetration and is irreplaceable in communications in extremely harsh environments. 2) The present invention constructs an electric small antenna through a sleeve capacitor structure and a spiral coil structure, which greatly achieves the miniaturization of the monopole electric small antenna in the long-wave frequency band. 3) The present invention proposes that by adjusting the size of the sleeve and the spacing and radius of the spiral coil, the resonant frequency of the monopole electric small antenna can be changed to meet the frequency band requirements in different environments. 4) The miniaturized antenna of the present invention can be used for portable transmitting antenna installation and long-wave frequency band applications in limited space. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 Schematic diagram of the structure of a long-wave frequency band monopole electric small antenna according to an embodiment of the present invention; Figure 2 A schematic structural diagram of a sleeve capacitor according to an embodiment of the present invention; Figure 3 A schematic diagram and dimensioning of the internal solid metal column and the top smaller metal plate of the sleeve capacitor structure according to an embodiment of the present invention; Figure 4 A schematic diagram and dimensioning of the outer hollow metal sleeve and the larger metal plate on the top of the sleeve capacitor structure according to an embodiment of the present invention; Figure 5 A schematic diagram of the structure and dimensions of the portion where the bottom metal floor and the sleeve capacitor are connected, according to an embodiment of the present invention; Figure 6 A schematic diagram of the structure and dimensions of a portion of the spiral coil according to an embodiment of the present invention; Figure 7 Schematic diagram of the reflection coefficient of the long-wave frequency band monopole electric small antenna according to an embodiment of the present invention; Figure 8 The radiation pattern of the long-wave frequency band monopole electric small antenna according to an embodiment of the present invention; Figure 9 Schematic diagram of another structure of a long-wave frequency band monopole electric small antenna according to an embodiment of the present invention; Reference numerals: 100 - sleeve capacitor structure, 101 - solid metal column and smaller metal plate on top, 102 - hollow metal sleeve and larger metal plate on top, 200 - spiral coil, 300 - bottom metal floor. DETAILED DESCRIPTION

[0014] The present invention will be further explained below with reference to the accompanying drawings. To facilitate a clear description of the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words such as "first" and "second" are used to distinguish between identical or similar items with substantially the same functions and effects. For example, the first threshold and the second threshold are merely used to distinguish between different thresholds and do not limit their order. Those skilled in the art will understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different. Example

[0015] like Figure 1 As shown, a long-wave frequency band monopole electric small antenna includes a sleeve capacitor structure 100, a spiral coil 200, and a bottom metal floor 300.

[0016] like Figures 2 to 4As shown, the sleeve capacitor structure 100 includes a solid metal column 101 and a first metal plate 102 at its top, a hollow metal sleeve 103 and a second metal plate 104 at its top. The hollow metal sleeve 103 is coaxially arranged on the outside of the solid metal column 101, and the hollow metal sleeve 103 and the solid metal column 101 inside do not contact each other. The first metal plate 102 is a metal plate with a smaller area, and the second metal plate 104 is a metal plate with a larger area. The first metal plate 102 is located directly above the second metal plate 104, and the first metal plate 102 and the second metal plate 104 do not contact each other. The top of the solid metal column 101 passes through the second metal plate 104 and is directly connected to the center of the bottom surface of the first metal plate 102. The top of the hollow metal sleeve 103 is connected to the bottom surface of the second metal plate 104.

[0017] like Figure 5 As shown, the bottom end of the solid metal column 101 is directly connected to the front center of the bottom metal floor 300. The bottom end of the hollow metal sleeve 103 is not connected to the bottom metal floor 300, and a gap is left between the two.

[0018] The two ends of the spiral coil 200 are respectively connected to the second metal plate 104 of the sleeve capacitor structure 100 and the bottom metal floor 300. In the spiral coil 200, the spacing between the coils is equal and they are distributed symmetrically around the sleeve capacitor structure 100.

[0019] Specifically, both ends of the spiral coil 200 are welded to corresponding metal plates by soldering.

[0020] The sleeve capacitor structure 100 is connected to the spiral coil 200 via the second metal plate 104. This is connected in parallel with the spiral coil 200, which is equivalent to an inductor, to form an LC resonant circuit. By adjusting the dimensions of the sleeve capacitor structure 100 and spiral coil 200, the equivalent capacitance and inductance values ​​can be changed, allowing the antenna to resonate within a specified frequency band.

[0021] In this embodiment, the radius R1 of the solid metal column 101 is 10 mm, the height L1 of the solid metal column 101 is 10000 mm, and the first metal plate 102 is a square metal plate with a side length W1 of 500 mm.

[0022] The inner diameter R of the hollow metal sleeve 103 in = 14mm, outer diameter R of the hollow metal sleeve 103 out = 20mm, the height L2 of the hollow metal sleeve 103 = 9900mm, and the second metal plate 104 is a square metal plate with a side length W2 = 1000mm.

[0023] The bottom metal floor 300 is a square metal plate with a side length W3 = 1000 mm, and the interval L3 between the hollow metal sleeve 103 and the bottom metal floor 300 is 100 mm.

[0024] like Figure 6 As shown, the diameter D1 of the spiral coil 200 is 995 mm, the spacing L4 between adjacent coils is 87 mm, and the total number of coils is 115.

[0025] like Figure 7 As shown, the antenna of this embodiment has a resonant frequency of 100 kHz, a relative bandwidth of 2%, and a size of approximately 1 / 300 wavelength.

[0026] like Figure 8 As shown, the antenna of this embodiment is placed on an infinite ground plane, and the radiation direction simulation diagram at a frequency of 100 kHz shows good omnidirectional radiation characteristics, and the maximum gain of the antenna is about -42 dBi. Example

[0027] like Figure 9 , which is another structural schematic diagram of the antenna of the present invention. The structural difference from Example 1 is that the spiral coil 200 is spherical as a whole and is distributed around the sleeve capacitor structure 100.

[0028] Although the present invention has been described with reference to specific features and embodiments thereof, it will be apparent that various modifications and combinations thereof may be made without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the present invention and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the invention. It will be apparent that various modifications and variations of the present invention may be made by those skilled in the art without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the invention and its equivalents.

Claims

1. A long-wave frequency monopole electric small antenna, characterized in that: It includes a sleeve capacitor structure (100), a spiral coil (200), and a bottom metal floor (300); The sleeve capacitor structure (100) comprises a solid metal column (101) and a first metal plate (102), a hollow metal sleeve (103) and a second metal plate (104); wherein the hollow metal sleeve (103) and the solid metal column (101) are coaxially arranged and do not contact each other with the solid metal column (101); the first metal plate (102) is located directly above the second metal plate (104); the top end of the solid metal column (101) passes through the second metal plate (104) and is connected to the center of the bottom surface of the first metal plate (102); the top end of the hollow metal sleeve (103) is connected to the second metal plate (104); the bottom end of the solid metal column (101) is connected to the bottom metal floor (300); and a gap is left between the bottom end of the hollow metal sleeve (103) and the bottom metal floor (300); The spiral coil (200) is distributed symmetrically around the sleeve capacitor structure (100), and two ends of the spiral coil (200) are respectively connected to the second metal plate (104) and the bottom metal floor (300) of the sleeve capacitor structure (100).

2. The long-wave frequency band monopole electric small antenna according to claim 1, characterized in that: The spiral coils (200) have the same radius and the spacing between the coils is equal.

3. The long-wave frequency band monopole electric small antenna according to claim 1, characterized in that: The spiral coil (200) is spherical in shape as a whole.

4. The long-wave frequency band monopole electric small antenna according to claim 1, characterized in that: The area of ​​the first metal plate (102) is smaller than the area of ​​the second metal plate (104).

5. The long-wave frequency band monopole electric small antenna according to any one of claims 1 to 4, characterized in that: The sleeve capacitor structure (100) is connected to the spiral coil (200) via a second metal plate (104), and is connected in parallel with the spiral coil (200) equivalent to an inductor to form an LC resonant circuit.

6. The long-wave frequency band monopole electric small antenna according to claim 2, characterized in that: The solid metal column (101) has a radius R1 = 10 mm and a height L1 = 10000 mm; the first metal plate (102) is a square metal plate with a side length W1 = 500 mm; the inner diameter R of the hollow metal sleeve (103) is in = 14mm, outer diameter R out = 20mm, height L2 = 9900mm; the second metal plate (104) is a square metal plate with a side length W2 = 1000mm; the bottom metal floor (300) is a square metal plate with a side length W3 = 1000mm, and the interval L3 between the hollow metal sleeve (103) and the bottom metal floor (300) is 100mm; the diameter D1 of the spiral coil (200) is 995mm, and the interval L4 between adjacent coils is 87mm.

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