An airbag buoy antenna in complex sea conditions and its design method

Abstract

The present invention discloses an airbag buoy antenna for complex sea conditions and its design method. The airbag buoy antenna comprises an air column 1, a radiator 2 attached to the air column, an inflation device 3, and a control module. The air column 1 is formed by an airbag that is inflated and expanded by the inflation device 3 and is stored in the airbag chamber 11 when not inflated. The radiator 2 is a shortwave communication antenna that is expanded and erected to a predetermined shape as the air column 1 is inflated and is stored when not inflated. The inflation device 3 is connected to the airbag chamber 11 and supplies air to the airbag. The control module is used to control the inflation device 3 according to the current tilt angle to adjust the diameter of the air column 1. When the antenna is not inflated, the airbag and radiator are folded and stored in the airbag chamber, making it easy to install and carry, without affecting the carrier's maneuverability and concealment, and ensuring performance stability in complex sea conditions.

Description

Technical Field

[0001] The present invention belongs to the field of wireless communications, and in particular relates to an airbag-type buoy antenna in complex sea conditions and a design method thereof. Background Art

[0002] Buoys, micro-sized underwater and surface vehicles, and other such objects are located at sea and are small, making it impossible to install antennas in large spaces and secure them at multiple points. Consequently, simple upright antennas are the only options. Due to the large physical size of shortwave antennas, they should be stored when not in use and quickly deployed before use. The antenna deployment method is also crucial. If a buoy is launched into the seawater from a submarine and rises to the surface due to its own buoyancy, it will be subject to the pressure and impact of the seawater during the ascent. Therefore, the antenna must be stored within the buoy during launch and then deployed once the buoy is above the surface. Therefore, the buoy antenna must be small, lightweight, and foldable. Furthermore, factors such as seawater and wind can affect the performance of the buoy antenna, leading to unstable performance. Summary of the Invention

[0003] In response to at least one of the above defects or improvement needs in the prior art, the present invention provides an airbag buoy antenna for complex sea conditions and a design method thereof. When the antenna is not inflated, the airbag and the radiator are folded and stored in the airbag chamber, which is convenient for installation and carrying, does not affect the maneuverability and concealment of the carrier, and can still ensure performance stability in complex sea conditions.

[0004] To achieve the above object, according to one aspect of the present invention, there is provided an airbag buoy antenna for use in complex sea conditions, comprising an air column 1, a radiator 2 attached to the air column, an inflation device 3, and a control module;

[0005] The air column 1 is formed by an airbag that is inflated and expanded by the inflator 3 and is stored in the airbag chamber 11 in an uninflated state;

[0006] The radiator 2 is a shortwave communication antenna, which is unfolded and erected to a predetermined shape as the air column 1 is inflated, and is in a stowed state when not inflated;

[0007] The inflation device 3 is connected to the airbag chamber 11 and supplies air to the airbag;

[0008] The control module is used to detect the current tilt angle of the airbag buoy antenna and control the inflation device 3 to adjust the diameter of the air column 1 according to the current tilt angle.

[0009] Preferably, the control module includes an acceleration sensor and a processor.

[0010] Preferably, the controlling of the inflation device 3 according to the current tilt angle comprises the steps of:

[0011] Analyze the effects of different tilt angles of the airbag buoy antenna on the resonant frequency, and determine the maximum allowable tilt angle of the airbag buoy antenna;

[0012] If the current tilt angle is greater than the maximum allowable tilt angle, the inflation device 3 is controlled to reduce the inflation amount to reduce the diameter of the air column 1 until the current tilt angle is within the maximum allowable tilt angle range;

[0013] If the current tilt angle is less than the maximum allowable tilt angle, the inflation device 3 is controlled to increase the inflation amount to increase the diameter of the air column 1 and ensure that the current tilt angle is within the maximum allowable tilt angle range.

[0014] Preferably, if the current tilt angle is less than the maximum allowable tilt angle, the inflation device 3 is controlled to increase the inflation amount to increase the diameter of the air column 1 until the difference between the current tilt angle and the maximum allowable tilt angle is less than a preset value.

[0015] Preferably, the length of the shortwave communication antenna is determined by the following steps:

[0016] Calculate and determine the theoretical length of the shortwave communication antenna according to a preset antenna theoretical length calculation formula;

[0017] The actual design length of the shortwave communication antenna is determined by calculation according to the center frequency and diameter of the shortwave communication antenna, the theoretical length and the compensation impedance.

[0018] Preferably, the air column 1 is cylindrical or conical.

[0019] Preferably, the radiator 2 is an upright whip antenna or a helical antenna after being unfolded.

[0020] Preferably, the radiator 2 is placed outside the air column 1 .

[0021] Preferably, the radiator 2 is placed inside the air column 1 .

[0022] According to another aspect of the present invention, there is provided a method for designing an airbag buoy antenna in complex sea conditions as described above, comprising the steps of:

[0023] Calculate and determine the theoretical length of the shortwave communication antenna according to a preset antenna theoretical length calculation formula;

[0024] The actual design length of the shortwave communication antenna is determined by calculation according to the center frequency and diameter of the shortwave communication antenna, the theoretical length and the compensation impedance.

[0025] The above preferred technical features can be combined with each other as long as they do not conflict with each other.

[0026] In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:

[0027] (1) The present invention provides an airbag-type buoy antenna for use in complex sea conditions and its design method, which is suitable for installation and use on platforms such as marine buoys, micro-sized underwater and surface vehicles, and vehicles, or other applications requiring a portable, rapidly deployable antenna. The antenna can be quickly deployed for transmitting or receiving radio signals. When the antenna is not inflated, the airbag and radiator are folded and stored within the airbag chamber, making it easy to install and carry without affecting the carrier's maneuverability and concealment. Furthermore, by adjusting the diameter of the air column, the buoy antenna can maintain stable performance in complex sea conditions.

[0028] (2) By installing an inflatable airbag with a radiator on a buoy or a micro underwater or surface vehicle, the transmission and reception of shortwave signals can be achieved without affecting the deployment of the buoy and the maneuverability and concealment of the vehicle.

[0029] (3) The helical antenna can increase the inductive reactance of the antenna on the basis of mirror doubling, so that the current at the top end is not zero, thereby increasing the effective height of the antenna.

[0030] (4) The shape of the antenna is switched by controlling the inflation of the inflatable device. The inflation volume is increased based on the spiral antenna, and the spiral antenna is switched to an upright whip antenna. When it is unfolded on the sea surface, the sea level is used as an infinite conductive plane, and the effective height is doubled by relying on the mirror principle.

[0031] (5) By switching the shape of the antenna, different antenna forms and performances can be actively switched according to needs or presets, which is an advantage that cannot be matched by a single antenna shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a front view of an example of a conical and spiral wire radiator of an airbag buoy antenna according to an embodiment of the present invention;

[0033] Figure 2 This is a front view of an example of a cylindrical and spiral wire radiator of an airbag buoy antenna according to an embodiment of the present invention;

[0034] Figure 3 is Figure 1 The conical spiral wire radiator is straightened and switched to the main view of the straight wire radiator example;

[0035] Figure 4 is Figure 2 The main view of the example of a cylindrical spiral wire radiator straightened and switched to a straight wire radiator;

[0036] Figure 5 This is a front view of an example of an airbag buoy antenna of the present invention, which is a conical and spiral wire radiator and an air pump inflation type;

[0037] Figure 6 This is a front view of an example of an airbag buoy antenna of the present invention, which is cylindrical and has a spiral wire radiator and is inflated by an air pump;

[0038] Figure 7 is Figure 5 The conical spiral wire radiator is straightened and switched to the main view of the straight wire radiator example;

[0039] Figure 8 is Figure 6 The main view of the example of a cylindrical spiral wire radiator straightened and switched to a straight wire radiator;

[0040] Figure 9 Schematic diagram of the design optimization principle of the airbag buoy antenna according to an embodiment of the present invention;

[0041] Figure 10-11 Schematic diagram of the air-ink-airbag interface of the airbag buoy antenna according to an embodiment of the present invention;

[0042] Figure 12 Schematic diagram of the impedance characteristics of the airbag buoy antenna at the sea surface according to an embodiment of the present invention;

[0043] Figure 13 1 is a schematic diagram showing how the reflection coefficient of the airbag buoy antenna according to an embodiment of the present invention varies with frequency when the antenna is at different tilt angles;

[0044] Figure 14 Schematic diagram of the reflection coefficient of the airbag buoy antenna according to the embodiment of the present invention changing with frequency when the air column diameter is different. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other. The present invention is further described in detail below with reference to specific embodiments.

[0046] like Figure 1-8 As shown, the present invention provides an airbag buoy antenna for complex sea conditions, comprising an air column 1, a radiator 2 attached to the air column, an inflation device 3 and a control module (not shown in the figure).

[0047] Air column 1 is formed by an airbag that is inflated and expanded by an inflating device 3. When not inflated, it is stored in airbag chamber 11, making it easy to install and carry. Radiator 2 is a shortwave communication antenna that expands and erects to a predetermined shape as air column 1 is inflated, and remains stored when not inflated. Inflating device 3 is connected to airbag chamber 11 and supplies air to the airbag. A control module detects the current tilt angle of the airbag buoy antenna and controls inflating device 3 based on this angle to adjust the diameter of air column 1.

[0048] The control module can be placed at any position of the airbag buoy antenna.

[0049] Further preferably, the control module is placed in the airbag chamber of the airbag buoy antenna.

[0050] Further preferably, the control module includes an acceleration sensor and a processor. The acceleration sensor is used to detect the current tilt angle of the airbag buoy antenna, and the processor is used to control the inflation device 3 to adjust the diameter of the air column 1 according to the current tilt angle.

[0051] Further preferably, the airbag buoy antenna is stored in the carrier and protected by the protective part when not in use.

[0052] The carrier is a floating body in water or underwater, specifically a buoy or a micro underwater or surface vehicle; or, the carrier is a mobile platform, specifically a vehicle, a single-soldier portable handbag or backpack; or, the carrier is other vehicles used in situations where a convenient and quickly deployable antenna is required.

[0053] like Figure 1-2 As shown, further preferably, the air column 1 is cylindrical or conical, with a diameter of generally 1-100 cm. When used for shortwave, the height can reach about ten meters, and the antenna height can reach ten meters.

[0054] Further preferably, the radiator 2 attached to the air column is a metal wire and can be placed outside or inside the air column 1 .

[0055] Further preferably, the radiator 2 is an upright whip antenna after being unfolded.

[0056] Further preferably, the radiator 2 is a helical antenna when unfolded, to which various loading and matching components can be attached. The helical antenna form can enhance the antenna's inductive reactance, while doubling its image, so that the current at its tip is not zero, thereby increasing the antenna's effective height and effectively offsetting the loss of effective height due to sea submergence.

[0057] like Figure 3-4As shown in Figures 7-8, further preferably, the inflator 3 controls the switching of antenna shapes by inflating the airbag. Based on the helical antenna, the amount of inflation is increased (during this process, the airbag not only increases in height but also twists in a spiral, requiring the airbag's material and telescopic properties to meet design requirements, such as flexibility and variableness). The helical antenna is then switched to an upright whip antenna. When deployed on the sea surface, the sea level is used as an infinitely large conductive plane, and the effective height is doubled by the mirror principle. Therefore, by switching the antenna shape, different antenna forms and performances can be actively switched according to needs or presets, which is an advantage that cannot be achieved with a single antenna shape.

[0058] like Figure 1-4 As shown, further preferably, the inflation device 3 includes a high-pressure gas cylinder 31 and an inflation control device (not shown in the figure). The inflation control device and the aforementioned control module exchange information.

[0059] Or, as Figure 5-6 As shown, the inflation device 3 includes an air pump 32 and an inflation control device (not shown in the figure). The inflation control device exchanges information with the aforementioned control module.

[0060] When the antenna needs to be deployed, the inflation device 3 is activated manually or automatically to inflate the airbag, so that the air pressure in the airbag reaches a predetermined pressure, the air column stands upright and reaches a predetermined wind resistance.

[0061] When not in use, the antenna is placed in the protective part of the carrier. Its small size does not affect the carrier's maneuverability and concealment. When in use, it can be quickly unfolded. The electrical size of the antenna can radiate short-wave electromagnetic waves with high efficiency.

[0062] The method of using the airbag buoy antenna includes the following steps:

[0063] S1. Manually or automatically open the protective portion of the carrier that houses the airbag buoy antenna;

[0064] S2. A manual or automatic control device activates the inflation device 3 to inflate the airbag and deploy the shortwave communication antenna to a predetermined configuration;

[0065] S3. The antenna transmits or receives electromagnetic waves.

[0066] Further preferably, step S2 includes the following steps:

[0067] S21, first unfold the shortwave communication antenna to the first form, that is, the helical antenna (correspondingly, step S3 includes step S31, first obtaining the first antenna performance and first detection information of the helical antenna).

[0068] S22: The antenna shape is switched by controlling the inflation of the inflator 3. Specifically, the helical antenna is inflated and increased (during this process, the airbag not only increases in height but also twists in a spiral, and the material and elastic properties of the airbag must meet design requirements, such as flexibility and displacement). The helical antenna is then switched to an upright whip antenna (correspondingly, after step S31, step S32 is performed: a second antenna performance and second detection information of the upright whip antenna are obtained).

[0069] Figure 9 The invention shows the design (optimization) principle of the airbag buoy antenna in complex sea conditions according to an embodiment of the invention.

[0070] Since the antenna works in an airbag above the sea surface, its working environment is a complex multi-media dynamic environment. A thin layer of seawater will inevitably adhere to the surface of the airbag, which adds a lot of difficulty to the design and optimization of the antenna.

[0071] Furthermore, the design (optimization) method of the airbag buoy antenna in complex sea conditions includes the steps of: respectively analyzing the electric field continuity of the normal component of the electric displacement vector in the airbag buoy antenna on the air-water film-airbag surface, the reflection coefficient of the electromagnetic wave at the air-water film-airbag boundary, and the electric field at the radiator (2) (shortwave communication antenna) after the electromagnetic field passes through the air, water film and airbag respectively; and determining the design optimization method of the airbag buoy antenna in complex sea conditions based on the analysis results.

[0072] The specific analysis is as follows:

[0073] (1) Electric field continuity

[0074] First, the Maxwell equations for electromagnetic wave propagation in seawater are listed:

[0075]

[0076] in, represents the gradient differential operator in calculus, J is the current density vector; the dielectric constant of seawater ε2 = 81; the electrical conductivity of seawater σ2 = 4S / m; the magnetic permeability of seawater is the same as that of air, μ = 4π×10 -7 H / m; H is the magnetic field intensity vector; E is the electric field intensity vector; D is the displacement current vector; B is the magnetic induction intensity vector.

[0077] Based on Equation (1), the electric field continuity of the electromagnetic wave passing through the water film on the surface of the airbag is calculated. The thickness of the water film is much smaller than the wavelength of the electromagnetic wave in air or seawater, so the surface charge density of the water film can be approximately considered as the volume charge density of the water film, ρ = 0. By deducing the Maxwell equations in seawater, Equation (2) is obtained.

[0078] In formula (2), ε represents the dielectric constant. Formula (2) can verify that in the surface water film of the airbag, the conduction current density J≠0 does not affect the free charge density ρ=0.

[0079]

[0080] In the above formula, j represents the imaginary unit and ω represents the angular velocity. On the air-water film-airbag interface, a rectangular closed loop abcda is constructed, such as Figure 10 As shown. Make a cylindrical closed body with a base area of ​​ΔS and a height of Δh, as shown Figure 11 As shown in Figure 2, the rectangular loop and the cylindrical closed body are both half in air and half in the airbag. The electrical properties of the water film serve as the boundary condition at the interface between the two.

[0081] Apply the second equation of Maxwell's equations to Figure 10 In the equation (2.3.2), when the segments bc and da approach 0 infinitely, we get the following equation.

[0082]

[0083] Among them, e t is the tangential unit vector along the interface, E1 is the electric field intensity in air; E2 is the electric field intensity in seawater, dl is the smallest partitioning element in the integral, and c is the perimeter of the rectangle. Equation (3) yields the following relationship. This means that at the air-water film-airbag surface, the tangential component of the electric field intensity E is continuous.

[0084] E 1t =E 2t (4)

[0085] Among them, E 1t The tangential component of the electric field strength in air; E 2t Tangential component of the electric field strength in seawater.

[0086] Apply Maxwell's fourth equation to Figure 11 When Δh approaches 0, the contribution of the cylindrical side to the integral can be ignored. From formula (2), we can see that the volume charge density ρ S = 0. Substituting into , we can see that the normal component of the electric displacement vector is continuous on the air-water film-airbag surface.

[0087]

[0088] In the above formula, e n Represents the direction unit vector, D is the electric displacement vector; D1 is the electric displacement vector in air, D2 is the electric displacement vector in seawater; dS is the minimum area element divided by the integral; S is the area of ​​the top or bottom surface of the cylinder shown in the figure.

[0089] (2) Multilayer dielectric reflection coefficient

[0090] refer to Figure 10 and Figure 11 In the electromagnetic wave transmission model, when the electromagnetic wave encounters the interface composed of air and water film during transmission, part of the electromagnetic wave passes through the boundary and the other part is reflected by the interface. At this time, the definition of the reflection coefficient R can be written as:

[0091]

[0092] In formula (6), η1 and η2 are the normalized characteristic impedances of air and water film, respectively. In the three-layer medium of air-water film-airbag, the water film and airbag can be regarded as the input wave impedance Z relative to the air. in A whole medium. in The calculation formula is shown in formula (7).

[0093]

[0094] Where η3, k2, and d2 are the normalized characteristic impedance of the airbag and water film, the wave number of electromagnetic waves propagating in the water film, and the thickness of the water film, respectively. Substituting these into the equations yields the reflection coefficient at the air-water film boundary.

[0095]

[0096] Considering seawater as a good conductor, the electrical properties of a highly foamed airbag are similar to those of air. Substituting the water film thickness d2→0, η1→1, η2→0, and η3→1 into equations (7) and (8), we can obtain that the reflection coefficient of electromagnetic waves at the air-water film-airbag boundary approaches 0.

[0097] (3) Neglect effect of adjacent media

[0098] In a three-layer medium consisting of air, water film, and airbag, the water film thickness is negligible and the airbag thickness is also smaller than the wavelength. Therefore, electromagnetic waves propagate as surface waves at the air-airbag interface. Therefore, the wavelength of the electromagnetic wave received by the antenna inside the airbag is the same as the wavelength of the electromagnetic wave in the medium outside the adjacent medium. This is known as the adjacent medium neglect effect. The thickness of the adjacent medium is defined as being much smaller than the wavelength of the electromagnetic wave in the surrounding medium.

[0099] When analyzing an antenna covered by multiple layers of thin dielectric material, the antenna can be considered as an independent metal target and a multi-layer thin dielectric target. In this case, the electric field at the antenna can be considered as the superposition of the electric fields at the antenna when the multiple layers of dielectric material are in their original spatial positions in a vacuum. The expression for the superimposed electric field, E, is shown in Equation (9).

[0100] E=ξ1E1+ξ2E2+ξ3E3 (9)

[0101] Where ξ1, ξ2, and ξ3 are the normalized weighting coefficients of the electromagnetic field at the antenna after passing through air, water film, and airbag, respectively. E1, E2, and E3 are the electric field components at the antenna after passing through air, water film, and airbag, respectively. Electric field continuity analysis provides a theoretical basis for the superposition method. Combined with the conclusions from multilayer dielectric reflection coefficient analysis, it can be approximately assumed that ξ2 ≈ ξ3 ≈ 0. The electric field at the antenna covered by multiple thin dielectric layers can be ignored for the influence of adjacent media. The airbag only serves to protect the antenna from short-circuiting by seawater and to provide support; it has no effect on the propagation characteristics of electromagnetic waves.

[0102] Furthermore, through the above analysis, it can be seen that the design optimization method of the airbag buoy antenna on the complex sea surface should not adopt the antenna design method in non-free space, but should adopt the antenna design criteria in free space, that is, ignore the influence of the seawater medium, adopt the antenna design criteria in vacuum or air medium, and equate the airbag buoy antenna on the complex sea surface to the airbag buoy antenna in vacuum or air medium.

[0103] Furthermore, the length of the shortwave communication antenna is determined by the following steps: (1) calculating and determining the theoretical length of the shortwave communication antenna according to a preset antenna theoretical length calculation formula; and (2) calculating and determining the actual design length of the shortwave communication antenna according to the center frequency of the shortwave communication antenna, its diameter, theoretical length, and compensation impedance.

[0104] When the antenna is near an infinite conductive plane (such as seawater), the impedance characteristics will undergo a significant change, causing the resonance point to shift and the reflection coefficient to increase. Therefore, the actual working environment of the buoy antenna should be modeled and the imaginary part of the impedance should be calculated. By adjusting the antenna length to offset the interface shortening effect of the infinite conductive plane, the antenna can be designed and optimized in the next step. Figure 12 is the impedance characteristic of the airbag buoy antenna at the sea surface.

[0105] like Figure 12 As shown, the antenna is mostly capacitive within the shortwave frequency band. To compensate for this, the antenna needs to be appropriately lengthened before being redesigned.

[0106] In one embodiment, the compensation impedance is selected as 5 ohms, and the extended length is calculated as follows:

[0107]

[0108] Where 5 is the compensating inductive reactance, Δl is the extended length of the shortwave communication antenna, L is the theoretical length of the shortwave communication antenna, and the actual design length is the sum of the extended length and the theoretical length. λ is the wavelength corresponding to the center frequency of the shortwave band. The calculated extended length is 0.14ln(6.37d), where d is the diameter of the shortwave communication antenna.

[0109] The above formula (10) is also applicable to the helical antenna. However, for the helical antenna, Δl is the projection of its extended length on the central axis of the air column, and L is the projection of its theoretical length on the central axis of the air column.

[0110] Furthermore, controlling the inflation device (3) according to the current tilt angle comprises the steps of:

[0111] (1) Analyze the influence of different tilt angles of the airbag buoy antenna on the resonant frequency and determine the maximum allowable tilt angle of the airbag buoy antenna.

[0112] In one embodiment, taking the radiator (2) as an upright whip antenna after unfolding, Figure 13 The figure shows the frequency dependence of the reflection coefficient of the upright whip antenna at different tilt angles in seawater, where 0, 10, 20, and 30 represent tilt angles. As can be seen from the figure, when the buoy antenna is tilted within 30°, the resonant frequency shifts by approximately 1 MHz, and the -6dB bandwidth shifts by more than double, meeting the design requirements. Therefore, the maximum allowable tilt angle for the upright whip antenna is determined to be 30°.

[0113] (2) If the current tilt angle is greater than the maximum allowable tilt angle, the inflation device (3) is controlled to reduce the inflation amount to reduce the diameter of the air column (1) until the current tilt angle is within the maximum allowable tilt angle range; if the current tilt angle is less than the maximum allowable tilt angle, the inflation device (3) is controlled to increase the inflation amount to increase the diameter of the air column (1) and ensure that the current tilt angle is within the maximum allowable tilt angle range.

[0114] For spiral antennas, adjusting the diameter of the air column can adjust the effect of wind on the buoy antenna, thereby adjusting the tilt angle, and also adjust the diameter of the buoy antenna, thereby adjusting the bandwidth. For upright whip antennas, adjusting the diameter of the air column primarily adjusts the effect of wind on the buoy antenna, thereby adjusting the tilt angle. However, both methods can effectively improve the stability of the buoy antenna.

[0115] Furthermore, for the helical antenna, if the current tilt angle is less than the maximum allowable tilt angle, the inflation device (3) is controlled to increase the inflation amount to increase the diameter of the air column (1) until the difference between the current tilt angle and the maximum allowable tilt angle is less than a preset value, that is, the current tilt angle reaches the critical value of the maximum allowable tilt angle as much as possible. In this way, the bandwidth can be increased as much as possible.

[0116] Figure 14 The reflection coefficient of helical antennas with different diameters varies with frequency. 1, 5, 10, and 20 represent the diameter of the air column, in cm. Figure 14The results show that a 20cm diameter helical antenna structure provides good stability and bandwidth for airbag buoy antennas. These analysis results are applicable not only to cylindrical airbag buoy antennas but also to the optimization of conical airbag buoy antennas. For conical airbag buoy antennas, the diameter of the conical air column base is selected as the parameter.

[0117] from Figure 14 It can be seen that the larger the antenna diameter, the wider its bandwidth. However, an antenna diameter that is too large can easily lead to a distorted radiation pattern. Therefore, the larger the antenna diameter, the better. Instead, different and appropriate coil diameters should be used in different sea conditions.

[0118] In one embodiment, adjusting the diameter of the gas column comprises the steps of:

[0119] (1) In complex sea conditions, if the sensor data shows that the tilt range exceeds 30°, the airbag inflation volume should be reduced, the airbag diameter should be reduced, and the effect of wind on the buoy antenna should be reduced; by continuously processing the data feedback from the acceleration sensor, the airbag diameter is adjusted until the tilt range of the buoy antenna is within 30°; if in a few extremely complex sea conditions, the tilt range of the buoy antenna cannot be controlled within 30° by adjusting the airbag diameter, the antenna will be automatically retracted and communication will be interrupted.

[0120] (2) If the sensor data shows that the tilt range is within 30°, the airbag inflation volume should be increased to expand the antenna bandwidth until the sensor feedback data shows that the tilt range of the buoy antenna reaches the critical value of 30° to avoid excessive enlargement of the coil.

[0121] A method for designing an airbag buoy antenna in any of the above-mentioned complex sea conditions in an embodiment of the present invention includes the following steps:

[0122] Calculate and determine the theoretical length of the shortwave communication antenna according to a preset antenna theoretical length calculation formula;

[0123] The actual design length of the shortwave communication antenna is determined by calculation according to the center frequency and diameter of the shortwave communication antenna, the theoretical length and the compensation impedance.

[0124] The specific implementation of the design method is the same as above and will not be repeated here.

[0125] In summary, compared with the prior art, the solution of the present invention has the following significant advantages:

[0126] The airbag buoy antenna of the present invention is suitable for installation on platforms such as offshore buoys, micro-sized underwater and surface vehicles, and vehicles, as well as other applications requiring a portable, quickly deployable antenna. It can be quickly deployed to transmit or receive radio signals. When the antenna is not inflated, the airbag and radiator are folded and stored within the airbag chamber, making it easy to install and carry without affecting the carrier's maneuverability or concealment. Furthermore, by adjusting the diameter of the air column, the buoy antenna maintains stable performance even in complex sea conditions.

[0127] By installing an inflatable airbag with a radiator on a carrier such as a buoy or a micro underwater or surface vehicle, the transmission and reception of shortwave signals can be achieved without affecting the deployment of the buoy and the maneuverability and concealment of the carrier.

[0128] The helical antenna can increase the inductive reactance of the antenna on the basis of doubling the image, so that the current at the top end is not zero, thereby increasing the effective height of the antenna.

[0129] The shape of the antenna is switched by controlling the inflation of the inflatable device. The inflation volume is controlled to increase on the basis of the spiral antenna, and the spiral antenna is switched to an upright whip antenna. When it is unfolded on the sea surface, the sea level is used as an infinite conductive plane, and its effective height is doubled by relying on the mirror principle.

[0130] By switching the shape of the antenna, different antenna forms and performances can be actively switched according to needs or presets, which is an advantage that cannot be matched by a single antenna shape.

[0131] It should be understood that the system embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate, and may be located in one place or distributed across different network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present embodiment without inventive effort.

[0132] In addition, it should be understood by those skilled in the art that, in the application documents of the embodiments of the present invention, the terms "comprise", "include" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0133] In addition, in any of the above embodiments, the method is not necessarily executed in sequence according to the serial number. As long as it cannot be inferred from the execution logic that it must be executed in a certain order, it means that it can be executed in any other possible order.

[0134] In the description of the embodiment of the present invention, a large number of specific details are described. However, it should be understood that the embodiment of the embodiment of the present invention can be put into practice without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this specification. Similarly, it should be understood that in order to streamline the disclosure of the embodiment of the present invention and help understand one or more of the various inventive aspects, in the above description of the exemplary embodiments of the embodiment of the present invention, the various features of the embodiment of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof.

[0135] This method of disclosure, however, should not be interpreted as reflecting an intention that the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of an embodiment of the invention.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, rather than to limit them. Although the embodiments of the present invention have been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An airbag buoy antenna for use in complex sea conditions, characterized in that: It comprises an air column (1), a radiator (2) attached to the air column, an inflation device (3) and a control module; The air column (1) is formed by an airbag that is inflated and expanded by the inflation device (3) and is stored in the airbag chamber (11) in an uninflated state; The radiator (2) is a shortwave communication antenna, which is unfolded and erected to a predetermined shape as the air column (1) is inflated, and is in a stowed state when not inflated; The inflation device (3) is connected to the airbag chamber (11) and supplies air to the airbag; The control module is used to detect the current tilt angle of the airbag buoy antenna and control the inflation device (3) to adjust the diameter of the air column (1) according to the current tilt angle; The controlling of the inflation device (3) according to the current tilt angle comprises the following steps: Analyze the effects of different tilt angles of the airbag buoy antenna on the resonant frequency, and determine the maximum allowable tilt angle of the airbag buoy antenna; If the current tilt angle is greater than the maximum allowable tilt angle, controlling the inflation device (3) to reduce the inflation amount to reduce the diameter of the air column (1) until the current tilt angle is within the maximum allowable tilt angle range; If the current tilt angle is less than the maximum allowable tilt angle, the inflation device (3) is controlled to increase the inflation volume to increase the diameter of the air column (1), and ensure that the current tilt angle is within the maximum allowable tilt angle range.

2. The airbag buoy antenna for complex sea conditions according to claim 1, characterized in that: The control module includes an acceleration sensor and a processor.

3. The airbag buoy antenna for complex sea conditions according to claim 1, characterized in that: If the current tilt angle is less than the maximum allowable tilt angle, the inflation device (3) is controlled to increase the inflation amount to increase the diameter of the air column (1) until the difference between the current tilt angle and the maximum allowable tilt angle is less than a preset value.

4. The airbag buoy antenna for complex sea conditions according to claim 1, characterized in that: The length of the shortwave communication antenna is determined by the following steps: Calculate and determine the theoretical length of the shortwave communication antenna according to a preset antenna theoretical length calculation formula; The actual design length of the shortwave communication antenna is determined by calculation according to the center frequency and diameter of the shortwave communication antenna, the theoretical length and the compensation impedance.

5. The airbag buoy antenna for complex sea conditions according to claim 1, characterized in that: The air column (1) is cylindrical or conical.

6. The airbag buoy antenna for complex sea conditions according to claim 1, characterized in that: The radiator (2) becomes an upright whip antenna or a helical antenna after being unfolded.

7. The airbag buoy antenna for complex sea conditions according to claim 1, characterized in that: The radiator (2) is placed outside the air column (1).

8. The airbag buoy antenna for complex sea conditions according to claim 1, characterized in that: The radiator (2) is placed inside the air column (1).

9. A method for designing an airbag buoy antenna in complex sea conditions according to any one of claims 1 to 8, characterized in that: Including steps: Calculate and determine the theoretical length of the shortwave communication antenna according to a preset antenna theoretical length calculation formula; The actual design length of the shortwave communication antenna is determined by calculation according to the center frequency and diameter of the shortwave communication antenna, the theoretical length and the compensation impedance.

Images