CN114024133B - Novel dipole antenna - Google Patents

Abstract

The present invention provides a novel dipole antenna, comprising: the antenna comprises a feed source, a first main radiator, a second main radiator, a first parasitic radiator and a second parasitic radiator, wherein the first main radiator, the second main radiator, the first parasitic radiator and the second parasitic radiator are all linear conductors; the first main radiator is connected with the second main radiator through a feed source; the first parasitic radiator is connected with the first main radiator; the second parasitic radiator is connected with the second main radiator. The invention overcomes the defect of insufficient signal omni-directionality when the traditional linear whip antenna is inclined on the water surface by introducing the V-shaped scattering multi-section antenna structure design of the first parasitic radiator and the second parasitic radiator, so that the novel dipole antenna can still keep larger signal omni-directionality and gain under the condition of extremely fluctuating water surface, and the reliability of information transmission is improved.

Description

A new type of dipole antenna

technical field

The invention relates to the technical field of short-wave communication of surface unmanned boat antennas, in particular to a novel dipole antenna.

Background technique

Surface unmanned boats are usually used to perform surface missions, and use the whip antenna mounted on the top to send and receive information to short-range sea and air targets. Due to the small size and light weight of the hull, the height of its carrying antenna is greatly limited, and the ultra-short wave band is often used for communication. The traditional whip antenna has low cost, is easy to manufacture, and has good omnidirectionality in the upright state on the sea surface, which can ensure good communication effect.

However, because seawater is an excellent conductor, it has good shielding performance for high-frequency electromagnetic waves. As a result, when the traditional whip antenna is tilted due to the influence of seawater flow, the electromagnetic wave radiated from the side of the antenna that is closer to the sea surface It will be absorbed by seawater in large quantities (as shown in Figure 1), so that the receiving target cannot fully receive signals and obtain information, and the reliability of its information transmission needs to be improved.

SUMMARY OF THE INVENTION

In view of at least one defect or improvement requirement of the prior art mentioned in the background art, the present invention provides a novel dipole antenna, which is used to solve the technical problem of insufficient signal omnidirectionality when the traditional linear whip antenna is tilted on the water surface .

The present invention provides a novel dipole antenna, comprising: a feed source and a first main radiator, a second main radiator, a first parasitic radiator and a second parasitic radiator, all of which are linear conductors;

the first main radiator is connected to the second main radiator through the feed;

the first parasitic radiator is connected to the first main radiator;

The second parasitic radiator is connected to the second main radiator.

According to the novel dipole antenna provided by the present invention, the sum of the respective line lengths of the first main radiator, the second main radiator, the first parasitic radiator and the second parasitic radiator is the The half wavelength of the electromagnetic wave radiated by the new dipole antenna.

According to the novel dipole antenna provided by the present invention, the first parasitic radiator is movably connected to the first main radiator.

According to the novel dipole antenna provided by the present invention, the second parasitic radiator is movably connected to the second main radiator.

According to the novel dipole antenna provided by the present invention, the sum of the line lengths of the first parasitic radiator and the first main radiator is equal to the sum of the line lengths of the second parasitic radiator and the second main radiator and, and the sizes and shapes of the cross sections of the first main radiator, the second main radiator, the first parasitic radiator and the second parasitic radiator are all the same.

According to the novel dipole antenna provided by the present invention, the shape of the cross section is circular.

According to the novel dipole antenna provided by the present invention, the line lengths of the first main radiator and the second main radiator are equal.

According to the novel dipole antenna provided by the present invention, one or more of the first main radiator, the second main radiator, the first parasitic radiator and the second parasitic radiator are retractable of linear conductors.

The invention overcomes the defect of insufficient signal omnidirectionality when the traditional linear whip antenna is tilted on the water surface by introducing the "V-like" scattered multi-segment antenna structure design of the first parasitic radiator and the second parasitic radiator , so that the new dipole antenna can still maintain a large signal omnidirectionality and gain in the case of extremely turbulent water surface, which improves the reliability of information transmission.

Description of drawings

In order to explain the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some Embodiments, for those of ordinary skill in the art, under the premise of no creative work, drawings of other embodiments can also be obtained according to these drawings.

Fig. 1 is the working state schematic diagram of the conventional whip antenna mounted on the surface unmanned boat on the fluctuating sea surface in the prior art;

2 is a schematic structural diagram of a novel dipole antenna provided by an embodiment of the present invention;

3 is a schematic structural diagram of a new cylindrical symmetrical dipole antenna provided by an embodiment of the present invention;

4 is a schematic diagram of the radiation to a certain point in the far field by the main radiator of the new cylindrical symmetrical dipole antenna provided by the embodiment of the present invention;

5 is a schematic diagram of the radiation of a parasitic radiator to a certain point in the far field by a parasitic radiator of a new cylindrical symmetrical dipole antenna provided by an embodiment of the present invention;

6 is a schematic diagram of the state of the cylindrical symmetrical new dipole antenna tilted by Φ degrees relative to the sea level provided by an embodiment of the present invention;

7 is an equivalent diagram of the state of the new cylindrical symmetrical dipole antenna tilted by Φ degrees relative to the sea level provided by an embodiment of the present invention;

FIG. 8 is a comparison of the signal radiation patterns of the new cylindrical symmetrical dipole antenna provided by the embodiment of the present invention and the traditional whip antenna in a vertical state relative to the sea level;

9 is a comparison of the signal radiation patterns of the new cylindrical symmetrical dipole antenna provided by the embodiment of the present invention and the traditional whip antenna when the angle is inclined by 30 ^° relative to the sea level;

Reference number:

In FIG. 2, 1 is a first main radiator, 2 is a second main radiator, 3 is a first parasitic radiator, 4 is a second parasitic radiator, and 5 is a feed.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

As shown in FIG. 2 , an embodiment of the present invention provides a novel dipole antenna, including: a feed source 5 and a first main radiator 1 , a second main radiator 2 , and a first parasitic radiator 3 which are all linear conductors and the second parasitic radiator 4 .

The first main radiator 1 is connected to the second main radiator 2 through a feed 5 .

The first parasitic radiator 3 is connected to the first main radiator 1 .

The second parasitic radiator 4 is connected to the second main radiator 2 .

The feed is the basic component of the parabolic antenna and the Cassegrain antenna, and is the primary radiator of the high-gain antenna. Its function is to radiate the RF power from the feeder to the reflective surface or lens in the form of electromagnetic waves, so as to generate a suitable field distribution on the aperture to form the required sharp beam or shaped beam; The power leaking out from edges such as lenses or lenses should be as small as possible to achieve the highest possible gain.

A linear conductor is a linear stick-like distribution of conductors, making it look like a stick. The shape and size of the cross-section of these linear conductors can be different, and the lengths can also be different. The connection relationship between the linear conductors can be a fixed connection with a fixed relative position, or a movable connection with a fixed relative position. Connection (for example, the first parasitic radiator 3 and the first main radiator 1 are axially connected, and the steering along the axis is realized by the control system of the antenna).

Through the above "V-like" scattered multi-segment antenna structure design with parasitic radiators added, even on one side of the new dipole antenna (such as the side of the second main radiator 2 and the second parasitic radiator 4) When the water surface fluctuates completely and is completely immersed in water, the other side of the antenna (the side of the first main radiator 1 and the first parasitic radiator 3) will be lifted above the water surface and continue to radiate electromagnetic waves in all directions. Thus, the radiation blind area problem of the traditional whip antenna is overcome.

In order to minimize various adverse effects caused by the size of the antenna conductor itself, preferably, the thinner the first main radiator 1 , the second main radiator 2 , the first parasitic radiator 3 and the second parasitic radiator 4 the better.

Preferably, the sum of the respective line lengths l ₁ , l ₂ , l ₃ and l ₄ of the first main radiator 1 , the second main radiator 2 , the first parasitic radiator 3 and the second parasitic radiator 4 is equal to the new dual The half wavelength (λ/2) of the electromagnetic wave radiated by the polar antenna.

Preferably, the first parasitic radiator 3 is movably connected to the first main radiator 1 , and the connection manner of the second parasitic radiator 4 to the second main radiator 2 may be a fixed connection or an active connection.

More preferably, the first parasitic radiator 3 is movably connected to the first main radiator 1 and the second parasitic radiator 4 is movably connected to the second main radiator 2 .

The articulation of the parasitic radiator and the main radiator ensures that their relative positions can be changed if required.

For the convenience of engineering and the consideration of physical balance, preferably, the sum of the line lengths of the first parasitic radiator 3 and the first main radiator 1 is equal to the length of the second parasitic radiator 4 and the second main radiator 2 . The sum of the line lengths, and the sizes and shapes of the cross sections of the first main radiator 1, the second main radiator 2, the first parasitic radiator 3 and the second parasitic radiator 4 are all the same.

The shape of the cross-section of the antenna conductor may be square, triangle, ellipse, or circle, etc., the shape is not limited, and the above-mentioned technical problems can be solved. For the convenience of engineering and manufacturing, preferably, the shape of the cross section of the antenna conductor is circular.

Preferably, the line lengths of the first main radiator 1 and the second main radiator 2 are the same, and the line lengths of the first parasitic radiator 3 and the second parasitic radiator 4 are the same. This fully symmetrical design makes the signal radiated by the antenna more stable.

Preferably, one or more of the first main radiator 1 , the second main radiator 2 , the first parasitic radiator 3 and the second parasitic radiator 4 are stretchable linear conductors. In this way, the overall line lengths of the radiators (the respective line lengths l ₁ , l ₂ , l ₃ of the first main radiator 1 , the second main radiator 2 , the first parasitic radiator 3 and the second parasitic radiator 4 ) , l ₄ ) can be adjusted according to actual needs. When it is necessary to radiate VHF electromagnetic waves of a certain frequency, it is only necessary to adjust the overall line length of the radiator to half of the wavelength of the electromagnetic waves of the frequency, thus avoiding the need for a separate manufacture for the radiation of VHF electromagnetic waves of a certain frequency. A set of corresponding new dipole antennas is cumbersome.

Combined with the practical needs of short-range maritime communication, the new dipole antenna in the VHF frequency band is designed to provide a realistic basis for surface unmanned boats to realize single-point communication in complex sea conditions, and also for the application of sea and air under high sea conditions. Communication provides reference. The VHF band communication not only ensures the rate of wireless communication at sea, but also enables the receiving target to obtain a better signal-to-noise ratio. The frequency range of the VHF band is 30 MHz -300 MHz. Combined with the whip antenna mounted on the surface unmanned boat It should not exceed 2 m, and 75 MHz is selected below (the resonant length of the whip antenna is 1 m) to verify the design structure and radiation performance of the new dipole antenna.

The total length of the new dipole antenna in Fig. 3 is λ/2, the physical length of one side of the main radiator antenna is l ₁ = l ₂ , and the included angle between the first main radiator and the second main radiator is α . Taking the single side antenna as an example, the length l ₃ of the first parasitic radiator can be calculated as λ/4− l ₁ . Number the nodes of the new dipole antenna, as shown in Figure 3, mark the feed point as O , and mark the intersection of the main radiator and the parasitic radiator as A and B, respectively, and divide the new dipole antenna into four segments. The four-segment antenna has a certain influence on the field strength of a certain point P ( r , θ , φ ) in the far field, so to solve the parameters of the new dipole antenna, it is necessary to obtain the superimposed field strength of the four-segment antenna radiation in the far field, so as to determine the antenna. Parameter indicators such as the length of each part and the angle α between the main radiators.

1. Field strength calculation

Without considering the influence of ocean waves, calculate the superimposed field strength of each part of the antenna in the far field. Since the antenna is a symmetrical structure, the current at point O is I ( O ), and at any point on the antenna, I _max = I ( O ), the currents at nodes A and B can be approximately expressed as:

Where k=2π/λ is the phase shift constant. The unilateral antenna parameters can be solved first, and the total antenna parameters can be solved by analogy. The micro-element method is used to divide the antenna into infinitely many current elements, and a polar coordinate system is established. For the electric fundamental oscillator, its far-field region expression is:

第一主辐射体1、第二主辐射体2与远场某点P和原点连线的夹角分别为β、γ，得到远场点P与两天线中点之间的距离为：As shown in FIG. 4 , for antennas with different angles, the coordinate systems on which they are based are also different, so coordinate system conversion is required. Take the left center point m and the right center point n of the new dipole antenna, and the corresponding polar coordinates are

The included angles between the first main radiator 1, the second main radiator 2 and a point P in the far field and the line connecting the origin are β and γ respectively, and the distance between the far field point P and the midpoint of the two antennas is:

According to the law of cosines, the included angle can be obtained:

The two-segment antenna can be regarded as a part of two symmetrical array elements in different directions. On the antenna element, take the current element segment dz from point O , and integrate it over the lengths l ₁ and l ₂ respectively. The contribution of the far-field point P is:

It can be found that if the field strength is superimposed at this time, the two antennas can cancel each other in some terms, but they must be processed separately here, because when the wave factor is considered, the impact of high sea conditions on the two antennas is different.

The parasitic radiator can be regarded as a part of an antenna, and can be calculated directly using the formula of the electric fundamental oscillator, and its equivalent diagram is shown in Figure 5.

The equivalent symmetrical element is parallel to the horizontal axis of the coordinate system, and the size of the antenna is very small. For a point P ( r , θ , φ ) in the far field, the angle with the vertical axis can be directly expressed by θ . The combined field strength at a point P is:

It can be concluded that the total radiation field strength of the new vertically placed new dipole oscillator at the far-field point P is:

It should be noted that when there is an influence of waves, the energy term absorbed by the waves needs to be deducted before superimposing the radiation field.

2. Radiation performance in tilted state

Surface unmanned boats often tilt when working on fluctuating seawater surfaces. At this time, if the tilt angle is too large, the communication blind area cannot be determined for traditional whip antennas. Considering that the receiving target is required to receive as large as possible The radiation field strength should not only ensure the omnidirectionality of the new dipole antenna, but also ensure that it still has a large gain in all directions when it is tilted.

Figure 6 shows the state when the antenna is tilted by an angle of Φ due to the influence of sea water. In order to avoid complex coordinate transformation, it can be equivalent to the antenna state in Figure 7. After the far-field radiation field strength is obtained, rotate along the plane where the antenna is located by Φ degrees to obtain Pattern of the new dipole antenna.

3. Simulation verification

The FEKO electromagnetic simulation software is used for simulation verification, a new type of dipole antenna model on the sea is established, and the method of moments is used to solve the electrical characteristics of the antenna. Assume that the angle between the main radiators is α = 60 ^o , the length of the two arms is l ₁ = l ₂ = 0.5 m, and the diameter of the antenna is 1 cm. In order to avoid the influence of seawater on the antenna current, a layer of polyethylene is wrapped around the antenna for insulation. .

Considering that the new dipole antenna is often difficult to maintain vertical in practical engineering, it is mostly operated at a certain angle of inclination. In order to ensure that the antenna can not only communicate at sea, but also realize short-range air-to-air communication, θ = 30 ^o is selected to compare the gain and direction diagram of the new dipole antenna and the traditional whip antenna in the vertical state and the inclined 30 ^o state. The simulation results are shown in Figure 8 , 9 shown.

By comparing the signal radiation pattern of the new dipole antenna with the traditional whip antenna, it can be found that the new dipole antenna has good omnidirectionality and relatively stable gain, which solves the radiation blind area problem of the traditional whip antenna.

The electrical characteristics of the proposed structure of the new dipole antenna are calculated above, which verifies the theoretical applicability of the new dipole antenna, and obtains its radiation performance parameters in all directions; based on the structure of the new dipole antenna, the electromagnetic simulation software The radiation model of the sea surface antenna was established in FEKO, and the gain, pattern and reflection coefficient of the VHF antenna were simulated and verified, and the new dipole antenna and the traditional whip antenna were simulated and verified in vertical and inclined conditions. The verification results show that the new dipole antenna can well solve the radiation blind area problem of the traditional whip antenna, and has good omnidirectionality and high gain, and this advantage increases with the increase of the tilt angle of the antenna affected by the waves. Continuously increasing; the verification results show that the new dipole antenna is an efficient, stable and omnidirectional antenna structure, which provides a new, omnidirectional and higher Gained antenna form, and provides theoretical support for the surface communication of the new dipole antenna in high sea conditions.

Note that the above are only some preferred embodiments of the present invention. Those skilled in the art will understand that the present invention is not limited to these specific embodiments described, and various obvious modifications, readjustments, equivalent substitutions or alternatives can be made by those skilled in the art within the spirit and principles of the present invention. Improvements and the like should all be included within the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention. The scope of the invention is determined by the scope of the appended claims.

Claims (6)

1. An omnidirectional dipole antenna for a surface unmanned boat, characterized in that it comprises: a feed source (5) and a first main radiator (1) and a second main radiator ( 2), a first parasitic radiator (3) and a second parasitic radiator (4); The first main radiator (1) is connected to the second main radiator (2) through the feed (5); and the first main radiator (1) is connected to the second main radiator (2) The included angle range between (0°, 180°); The first parasitic radiator (3) and the first main radiator (1) are movably connected with an adjustable angle; The second parasitic radiator (4) and the second main radiator (2) are movably connected with an adjustable angle. 2. The omnidirectional dipole antenna according to claim 1, wherein the first main radiator (1), the second main radiator (2), and the first parasitic radiator (3) ) and the respective line lengths of the second parasitic radiator (4) are the half wavelengths of the electromagnetic waves radiated by the omnidirectional dipole antenna. 3. The omnidirectional dipole antenna according to claim 2, characterized in that the sum of the line lengths of the first parasitic radiator (3) and the first main radiator (1) is equal to the second The sum of the line lengths of the parasitic radiator (4) and the second main radiator (2), and the first main radiator (1), the second main radiator (2), the first main radiator (2), the The size and shape of the cross section of the parasitic radiator (3) and the second parasitic radiator (4) are the same. 4. The omnidirectional dipole antenna according to claim 3, wherein the shape of the cross section is a circle. 5. The omnidirectional dipole antenna according to claim 3, characterized in that, the line lengths of the first main radiator (1) and the second main radiator (2) are equal. 6. The omnidirectional dipole antenna according to claim 2, wherein the first main radiator (1), the second main radiator (2), and the first parasitic radiator (3) ) and one or more of the second parasitic radiators (4) are retractable linear rods.

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