CN114678691A - Low profile broadband conformal antenna elements and arrays - Google Patents

Abstract

The invention provides a low-profile broadband conformal antenna unit and an array, wherein the low-profile broadband conformal antenna unit comprises: a carrier having an open cavity; a cell structure comprising: a rectangular ground disposed on an inner side surface of the cavity; the L-shaped feed unit is arranged in the cavity and comprises a gradually-changed feed patch and a gradually-changed feed probe which are vertically arranged, wherein the gradually-changed feed probe is vertical to the bottom surface of the cavity; the feed structure is arranged in the cavity and is respectively connected with the rectangular ground and the gradual change type feed probe; the antenna housing is arranged at the opening of the cavity body to cover the opening and is conformal with the carrier; conformal radiating element and parasitic radiating element, the interval sets up and all laminates the one side of setting towards the cavity at the antenna house, all conformal with the antenna house. The problem that the traditional L-shaped feed antenna is of a planar structure, the working bandwidth is limited, and the requirement for covering wide-angle-domain beams under the installation constraint of a special-shaped surface of an aircraft platform is difficult to meet can be solved.

Description

Low Profile Broadband Conformal Antenna Element and Array

technical field

The invention belongs to the technical field of radar and broadband wireless communication, and relates to a low-profile broadband conformal antenna unit and an array, which can be applied to the transceiver of broadband radio frequency signals.

Background technique

The L-shaped feed antenna has the common advantages of microstrip antennas such as miniaturization, low profile, low cost, and light weight, and also overcomes the problem of narrow bandwidth of common microstrip antennas. Current L-shaped feed antennas usually consist of horizontal and vertical probes and a radiating patch above the probes. The vertical part and the horizontal part of the L-shaped probe can be coupled with the radiating patch for feeding, and the inductive and capacitive reactances generated between them interact to generate resonance, which can widen the antenna frequency band. Because of the above advantages, L-type probe feed antennas have been widely used in communication systems. However, the traditional L-shaped feed antenna has a planar structure and limited operating bandwidth, which makes it difficult to meet the wide-angle beam coverage requirements under the installation constraints of the special-shaped surface of the aircraft platform.

SUMMARY OF THE INVENTION

The present invention aims to solve at least one of the technical problems existing in the prior art.

To this end, the present invention provides a low-profile broadband conformal antenna unit and array.

The technical solution of the present invention is as follows:

According to one aspect, a low-profile broadband conformal antenna unit is provided, the low-profile broadband conformal antenna unit comprising:

a carrier having an open cavity on the carrier;

Unit structure, the unit structure includes:

Rectangularly, the rectangle is disposed on the inner side surface of the cavity;

L-shaped feeding unit, the feeding unit is disposed in the cavity, and includes a gradient feeding patch and a gradient feeding probe arranged perpendicular to each other, wherein the gradient feeding probe is perpendicular to the the bottom surface of the cavity;

a feeding structure, the feeding structure is arranged in the cavity, and the feeding structure is respectively connected with the rectangular ground and the gradient feeding probe;

a radome, the radome is disposed at the opening of the cavity to cover the opening, and the radome is conformal to the carrier;

The conformal radiating element and the parasitic radiating element, the conformal radiating element and the parasitic radiating element are arranged at intervals and are attached to the side of the radome facing the cavity, and the conformal radiating element and the parasitic radiating element are both arranged with the radome. The radomes are conformal and are commonly used for radiation of high-frequency electromagnetic signals.

Further, the tapered feeding probe is a circular truncated structure, the axis of the circular truncated structure is perpendicular to the bottom surface of the cavity, the top surface of the circular truncated structure is connected to the feeding structure, and the bottom surface of the circular truncated structure is connected to the gradient type. The feeding patch is connected, wherein the top surface is arranged close to the bottom surface of the cavity, and the area of the top surface is smaller than that of the bottom surface.

Further, the gradient feeding patch is an isosceles trapezoid structure, the side where the lower bottom of the isosceles trapezoid structure is located is connected to the bottom surface of the circular truncated structure, and the projection of the lower bottom on the bottom surface is the diameter of the bottom surface. completely coincident.

Further, the modified feeding patch and the gradient feeding probe are integrally formed.

Further, the radome is made of wave-transmitting material.

Further, the feeding structure is a coaxial feeding structure, comprising an inner conductor and an outer conductor arranged coaxially, wherein the inner conductor is connected with the tapered feeding probe, and the outer conductor is connected with the rectangular ground.

Further, the cavity is a rectangular metal cavity, and/or the projections of the conformal radiation unit and the parasitic radiation unit on the bottom surface of the cavity are both rectangular.

According to another aspect, a low-profile broadband conformal antenna array is provided, the low-profile broadband conformal antenna array comprising a plurality of the above-described low-profile broadband conformal antenna elements.

Further, in the antenna array, the carriers of the plurality of low-profile broadband conformal antenna units form an integral structure.

Further, the plurality of unit structures included in the antenna array are divided into a first group and a second group, wherein the first group includes a plurality of unit structures, the second group also includes a plurality of unit structures, and the first group includes a plurality of unit structures. The unit structure and the plurality of unit structures of the second group are all arranged at intervals along the first direction of the integrated structure, and the plurality of unit structures of the first group and the plurality of unit structures of the second group are also arranged opposite to the two sides of the integrated structure and meet one another. A corresponding setting.

In the above technical solution, by designing the L-shaped feeding unit to include feeding probes and feeding patches with a gradient structure, impedance matching can be improved and bandwidth can be expanded. At the same time, since the antenna unit is placed inside the metal cavity, the gain is increased but the standing wave situation is deteriorated. By designing the unit to include a conformal radiation unit and a parasitic radiation unit, and designing the radome, that is, the dielectric matching layer, on the two radiation patches, And make the dielectric matching layer conformal to the surface of the carrier, which can improve the standing wave of the antenna, and at the same time increase the gain of the antenna in the required angle range, even if the radiation pattern of the antenna as a whole shifts in the downward direction of the azimuth, widening the gain bandwidth of the antenna.

The antenna unit provided by the present invention is a wide-angle, high-gain, miniaturized, and conformal antenna unit with the surface of the carrier, which satisfies low standing waves, high gain, and wide bandwidth within a specific lateral angle range within the required frequency band. The present invention further constructs an antenna array based on the antenna unit, which lays a foundation for high-precision direction finding.

Description of drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention, constitute a part of the specification, are used to illustrate the embodiments of the invention, and together with the description, serve to explain the principles of the invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

1 is a top view of a low-profile broadband conformal antenna array of the present invention;

Fig. 2 is the front view of Fig. 1;

Figure 3 is an exploded view of the low profile broadband conformal antenna element of the present invention.

4 is a standing wave diagram of an L-shaped gradient probe fed conformal antenna according to the present invention;

5 is the gain curve of the antenna unit of the present invention when the azimuth angle is in the range of 45°-135° at the low frequency f1, and the pitch angle is selected from three angles of 75°, 95°, and 105°.

6 is the gain curve of the antenna unit of the present invention when the azimuth angle is in the range of 45°-135° and the pitch angle is selected at three angles of 75°, 95° and 105° at the intermediate frequency f2.

7 is the gain curve of the antenna unit of the present invention when the azimuth angle is in the range of 45°-135° and the elevation angle is selected at three angles of 75°, 95° and 105° at high frequency f3.

Reference number:

1-radome; 2-parasitic radiation element; 3-conformal radiation element; 4-graded feed patch; 5-integrated structure; 5a-carrier; 6-graded feed probe; 7-rectangular ground; 8-outer conductor; 9-inner conductor; 10-cavity; 11-unit structure.

Detailed ways

It should be noted that the embodiments in the present application and the features of the embodiments may be combined with each other in the case of no conflict. The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that There are features, steps, operations, devices, components and/or combinations thereof.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the invention unless specifically stated otherwise. Meanwhile, it should be understood that, for the convenience of description, the dimensions of various parts shown in the accompanying drawings are not drawn in an actual proportional relationship. Techniques, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the authorized description. In all examples shown and discussed herein, any specific value should be construed as illustrative only and not as limiting. Accordingly, other examples of exemplary embodiments may have different values. It should be noted that like numerals and letters refer to like items in the following figures, so once an item is defined in one figure, it does not require further discussion in subsequent figures.

As shown in FIGS. 1-7 , in one embodiment of the present invention, a low-profile broadband conformal antenna unit is provided. The low-profile broadband conformal antenna unit includes a carrier 5 a and a unit structure 11 , and the carrier 5 a has a An open cavity 10; the unit structure 11 includes a rectangular ground 7, an L-shaped feeding unit, a feeding structure, a radome 1, a conformal radiating element 3 and a parasitic radiating element 2, and the rectangular ground 7 is arranged on the On the inner surface of the cavity 10; the feeding unit is arranged in the cavity 10, and includes a gradient feeding patch 4 and a gradient feeding probe 6 arranged perpendicular to each other, wherein the gradient feeding The electrical probe 6 is perpendicular to the bottom surface of the cavity 10; the feeding structure is arranged in the cavity 10 and is connected to the rectangular ground 7 and the gradient feed probe 6 respectively; the radome 1 is arranged at the opening of the cavity 10 to cover the opening, and the radome 1 is conformal to the carrier 5a; the conformal radiating element 3 and the parasitic radiating element 2 are arranged at intervals and are arranged in close contact with each other. On the side of the radome 1 facing the cavity 10, the conformal radiating element 3 and the parasitic radiating element 2 are both conformal to the radome 1, and are jointly used for radiation of high-frequency electromagnetic signals.

For example, the cavity 10 may be a rectangular metal cavity 10 , the depth of the cavity 10 may be 67.03 mm, and the plane size may be 150 mm*150 mm, as the installation environment of the unit structure 11 .

For example, the gradient feeding patch 4 and the gradient feeding probe 6, the conformal radiating element 3 and the parasitic radiating element 2 are all patches and are also ideal conductors. The gradient-type feeding probe 6 is fed and excited by the feeding structure, and the feeding patch couples and feeds the upper conformal radiating element 3 .

It can be seen that the above technical solution can improve the impedance matching and expand the bandwidth by designing the L-shaped feeding unit to include the feeding probe and the feeding patch of the gradient structure. At the same time, since the antenna unit is placed inside the metal cavity, the gain is increased but the standing wave situation is deteriorated. By designing the unit to include a conformal radiation unit and a parasitic radiation unit, and designing the radome, that is, the dielectric matching layer, on the two radiation patches, And make the dielectric matching layer conformal to the surface of the carrier, which can improve the standing wave of the antenna, and at the same time increase the gain of the antenna in the required angle range, even if the radiation pattern of the antenna as a whole shifts in the downward direction of the azimuth, widening the gain bandwidth of the antenna.

That is, in the embodiment of the present invention, by applying the design of a metal cavity, a feed unit with a gradient shape, and a radome and a radiating element, the antenna element maintains a small size, a wide frequency band, and a wide angular domain height when the radiating element is conformal. Gain beam coverage characteristics.

According to an embodiment of the present invention, in order to realize the L-band antenna scheme of lateral radiation, the cavity 10 is designed to be located on the side of the carrier 5a, that is, a metal cavity 10 is opened on the side of the carrier 5a, and feeds the The electrical unit and the radiation unit are arranged inside the cavity 10 to form an L-shaped probe feed antenna, which satisfies the L-band antenna scheme of realizing lateral radiation in the metal cavity 10 on the side of the carrier 5a.

In the above embodiment, in order to better improve impedance matching and thus better expand the bandwidth:

The tapered feeding probe 6 has a circular truncated structure, the axis of the circular truncated structure is perpendicular to the bottom surface of the cavity 10 , the top surface of the circular truncated structure is connected to the feeding structure, and the bottom surface of the circular truncated structure is connected to the tapered feeder. The electrical patch 4 is connected, wherein the top surface is disposed close to the bottom surface of the cavity 10, and the area of the top surface is smaller than that of the bottom surface.

The gradient feeding patch 4 is an isosceles trapezoid structure, the side where the lower bottom of the isosceles trapezoid structure is located is connected to the bottom surface of the circular truncated structure, and the projection of the lower bottom on the bottom surface completely coincides with the diameter of the bottom surface. .

That is, along the direction away from the bottom surface of the cavity 10 , the radius of the gradient feed probe 6 increases as the height increases, showing a rounded truncated truncated structure. The upper end of the gradient feeding probe 6 is connected with a gradient feeding patch 4, and the width decreases as the length increases, showing an isosceles trapezoid shape. That is, the embodiment of the present invention is based on the basic broadband principle of the L-shaped probe feed antenna. By designing the specific gradient shape of the gradient feeding probe 6 and the gradient feeding patch 4 as a positional relationship, the impedance can be better improved. matching to better expand the bandwidth.

Preferably, the modified feeding patch and the gradient feeding probe 6 are integrally formed.

In the above embodiment, in order to better improve the influence of the reflection of the metal cavity on the standing wave, the radome 1 is made of a wave-transmitting material.

That is, when the L-shaped probe feed antenna is surrounded by an ideal electrical boundary, its performance at medium and low frequencies will be greatly deteriorated due to the strong reflection effect brought by the conductor boundary. A layer of wave-transmitting material is added above the radiation patch to make it conformal to the surface of the carrier 5a, thereby improving the influence of the reflection of the metal cavity 10 on the standing wave, and finally realizing the improvement of the standing wave performance of the antenna in the medium and low frequency bands. The performance of the antenna is improved without changing the shape of the radiating element, and the conformal effect is achieved.

According to an embodiment of the present invention, the feed structure is a coaxial feed structure, including an inner conductor 9 and an outer conductor 8 arranged coaxially, wherein the inner conductor 9 is connected to the tapered feed probe 6 , the outer conductor 8 is connected to the rectangular ground 7 .

That is, the lower end of the tapered feeding probe 6 is connected to the inner conductor 9 for feeding excitation, and the tapered feeding patch 4 couples and feeds the upper conformal radiating element 3 . The outer conductor 8 of the coaxial feed structure is connected to the rectangular ground 7 .

In the embodiment of the present invention, the coaxial feed structure includes an inner conductor 9, an outer conductor 8 and an excitation port. The outer conductor 8 is supported on the rectangular ground 7, and a hole is opened at a specific position of the rectangular ground 7. The diameter of the hole is 9.2 mm. The off-axis conductor 8 is connected to the rectangular ground 7 . The upper end of the inner conductor 9 is connected to the lower end of the tapered feeding probe 6. The inner conductor 9 has a diameter of 4 mm and a length of 6 mm, which is reserved for the excitation port and does not affect the performance of the antenna. The characteristic impedance of the coaxial feed structure is 50Ω.

Preferably, the diameter of the lower end of the tapered feeding probe 6 and the diameter of the inner conductor 9 are both 4 mm, the diameter of the upper end of the tapered feeding probe 6 is 12 mm, and the height is 27.105 mm. The width of the end of the gradient feeding patch 4 connected to the gradient feeding probe 6 is 12 mm, the width of the distal end is 3 mm, and the length is 19 mm.

Preferably, the projections of the conformal radiation unit 3 and the parasitic radiation unit 2 on the bottom surface of the cavity 10 are both rectangular.

In this embodiment, the conformal radiating element 3 is an ideal conductor, and the lower part is coupled and fed by the gradient feeding patch 4 . The conformal radiating element 3 is conformal to the radome 1 , that is, the shape of the conformal radiating element 3 is a rectangular arc surface, the projection surface along the direction of the metal cavity 10 is a rectangle, and its extended size is 55mm*35mm.

In this embodiment, the parasitic radiation element 2 is an ideal conductor, and its level is the same as that of the conformal radiation patch, and the center distance between the two is 89.5 mm. The parasitic radiating element 2 is conformal to the radome 1 and is a rectangular arc surface, and its size after extension is 60mm*39mm.

In addition, the size of the rectangular ground 7 in the above embodiment can be 150mm*150mm, which can be used as the reference ground of the antenna.

As shown in FIGS. 1-2 , according to another embodiment of the present invention, a low-profile broadband conformal antenna array is provided, and the low-profile broadband conformal antenna array includes a plurality of the above-mentioned low-profile broadband conformal antenna units.

That is, the embodiment of the present invention further constructs an antenna array based on the antenna unit, which lays a foundation for high-precision direction finding.

Preferably, in the antenna array, the carriers 5 a of the plurality of low-profile broadband conformal antenna units are an integral structure 5 .

That is, the multiple carriers 5a of the multiple low-profile broadband conformal antenna units are all part of the integrated structure 5, and the multiple carriers 5a together form the integrated structure 5, and the integrated structure 5 serves as the carrier of the entire array, as shown in FIG. 1 . As shown in -2, the cylindrical-like integral structure 5, the radius of the cylindrical-like is approximately 300mm.

In the above embodiment, in order to realize a lateral antenna array, the plurality of unit structures 11 included in the antenna array are divided into a first group and a second group, wherein the first group includes a plurality of unit structures 11, and the second group also includes Including a plurality of unit structures 11, the plurality of unit structures 11 of the first group and the plurality of unit structures 11 of the second group are arranged at intervals along the first direction of the integrated structure 5, and the plurality of unit structures 11 of the first group and the second group The plurality of unit structures 11 of the group are also arranged oppositely on both sides of the integrated structure 5 and are arranged in a one-to-one correspondence.

That is, the antenna array includes an integrated structure 5 , and the integrated structure 5 has two groups of cavities 10 , and each group of cavities 10 includes a plurality of cavities 10 spaced along the first direction of the integrated structure 5 . , two sets of cavities 10 are symmetrically arranged on both sides of the integrated structure 5 , wherein the multiple cavities 10 of one set of cavities 10 serve as the installation environment of the multiple unit structures 11 of the first set, and the multiple cavities 10 of the other set Each cavity 10 is used as the installation environment of the plurality of unit structures 11 of the second group, and the connection relationship is consistent with the above-mentioned antenna units.

For example, the first direction may be the axial direction of the integrated structure 5 .

As shown in FIG. 4 , the standing wave of the L-shaped gradient probe-fed conformal antenna unit of the present invention is less than 3.0 in the relative bandwidth greater than 25%.

As shown in FIG. 5 , the L-shaped gradient probe-fed conformal antenna unit of the present invention has a minimum gain of 0.78dBi in the pitch angle range of -15°-15° and the azimuth angle of 45°-135° at the low frequency f1. (The three curves from top to bottom are 15 degrees in pitch, 5 degrees in elevation, and 15 degrees in elevation)

As shown in FIG. 6 , the L-shaped gradient probe-fed conformal antenna unit of the present invention has a minimum gain of 1.82dBi in the pitch angle range of -15°-15° and the azimuth angle of 45°-135° at the intermediate frequency f2. (The three curves from top to bottom are 15 degrees in pitch, 5 degrees in elevation, and 15 degrees in elevation)

As shown in FIG. 7 , the L-shaped gradient probe-fed conformal antenna unit of the present invention has a minimum gain of 0.76dBi in the pitch angle range of -15°-15° and the azimuth angle of 45°-135° at high frequency f3. (The three curves from top to bottom are 15 degrees in pitch, 5 degrees in elevation, and 15 degrees in elevation)

To sum up, the purpose of the present invention is to provide a lateral unit with wide-angle range, high gain, miniaturization, and a lateral antenna conformal to the surface of the carrier, which satisfies the requirement of low frequency within a specific lateral angle range within the required frequency band. The requirements of standing wave, high gain and wide bandwidth further construct an antenna array based on this antenna, which lays the foundation for high-precision direction finding.

For ease of description, spatially relative terms, such as "on", "over", "on the surface", "above", etc., may be used herein to describe what is shown in the figures. The spatial positional relationship of one device or feature shown to other devices or features. It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or features would then be oriented "below" or "over" the other devices or features under other devices or constructions". Thus, the exemplary term "above" can encompass both an orientation of "above" and "below." The device may also be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein interpreted accordingly.

In addition, it should be noted that the use of words such as "first" and "second" to define components is only for the convenience of distinguishing corresponding components. Unless otherwise stated, the above words have no special meaning and therefore cannot be understood to limit the scope of protection of the present invention.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A low-profile broadband conformal antenna unit, comprising:

a carrier having an open cavity therein;

a cell structure, the cell structure comprising:

a rectangular ground disposed on an inside surface of the cavity;

the L-shaped feed unit is arranged in the cavity and comprises a gradual change type feed patch and a gradual change type feed probe which are vertically arranged, wherein the gradual change type feed probe is vertical to the bottom surface of the cavity;

the feed structure is arranged in the cavity and is respectively connected with the rectangular ground and the gradual change type feed probe;

a radome disposed at an opening of the cavity to cover the opening, the radome conforming to the carrier;

Conformal radiating element and parasitic radiating element, conformal radiating element and parasitic radiating element interval set up and all laminate the setting and be in the one side of orientation cavity of antenna house, conformal radiating element and parasitic radiating element all with the antenna house is conformal, is used for high frequency electromagnetic signal's radiation jointly.

2. The low-profile broadband conformal antenna unit according to claim 1, wherein the tapered feed probe is a truncated cone structure, an axis of the truncated cone structure is perpendicular to the bottom surface of the cavity, a top surface of the truncated cone structure is connected to the feed structure, and the bottom surface of the truncated cone structure is connected to the tapered feed patch, wherein the top surface is disposed close to the bottom surface of the cavity, and an area of the top surface is smaller than an area of the bottom surface.

3. The low-profile broadband conformal antenna unit according to claim 2, wherein the tapered feed patch is an isosceles trapezoid structure, a side of the isosceles trapezoid structure where a lower bottom is located is connected to the bottom surface of the truncated cone structure, and a projection of the lower bottom on the bottom surface completely coincides with a diameter of the bottom surface.

4. A low-profile broadband conformal antenna element according to claim 2 or 3, wherein the modified feed patch and the modified feed probe are integrally formed.

5. A low-profile, broadband conformal antenna unit according to any one of claims 1-3, wherein the radome is made of a wave-transparent material.

6. The low-profile broadband conformal antenna element according to claim 1, wherein the feeding structure is a coaxial line feeding structure comprising an inner conductor and an outer conductor coaxially disposed, wherein the inner conductor is connected to the tapered feeding probe and the outer conductor is connected to the rectangular ground.

7. The low-profile broadband conformal antenna unit according to claim 1, wherein the cavity is a rectangular metal cavity, and/or projections of the conformal radiating element and the parasitic radiating element on a bottom surface of the cavity are rectangular.

8. A low-profile broadband conformal antenna array, comprising a plurality of low-profile broadband conformal antenna elements of any one of claims 1-7.

9. The low-profile broadband conformal antenna array according to claim 8, wherein the carriers of the plurality of low-profile broadband conformal antenna elements form a unitary structure.

10. The low-profile broadband conformal antenna array according to claim 9, wherein the antenna array comprises a plurality of unit structures divided into a first group and a second group, wherein the first group comprises the plurality of unit structures, the second group also comprises the plurality of unit structures, the plurality of unit structures of the first group and the plurality of unit structures of the second group are arranged at intervals along the first direction of the integrated structure, and the plurality of unit structures of the first group and the plurality of unit structures of the second group are further arranged on two sides of the integrated structure in an opposite manner and in a one-to-one correspondence manner.

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