KR100808791B1 - Drag Reduction Type Antenna Cover - Google Patents

Abstract

The present invention relates to a drag reduction mobile antenna cover capable of reducing drag caused by wind pressure such as typhoons and gusts.

The present invention continuously forms the first buffer portion and the second buffer portion at both front and side boundary portions of the antenna cover, and are formed in a cross section having the same shape as the outer shape of the antenna cover, respectively. It consists of a top cap and a bottom cap to accommodate the first shock absorber and the second shock absorber to reduce the drag caused by the gust by adjusting the speed of the airflow properly, thereby preventing human physical damage from the destruction or overturning of the communication tower In addition, the directivity of the antenna is maintained so that there is no change in the propagation characteristics.

Mobile communication, antenna, drag

Description

Drag reduction type antenna cover for mobile communication {.}

1 is a perspective view of a conventional mobile communication antenna

Figure 2 is a cross-sectional view showing the flow of air flow in the antenna cover for a conventional mobile communication

3 is a perspective view of a mobile communication antenna of the present invention;

Figure 4 is an exploded perspective view of the antenna cover for mobile communication of the present invention

Figure 5 is a cross-sectional view showing the flow of air flow in the antenna cover for mobile communication of the present invention

Figure 6 is a cross-sectional view showing the flow of air flow in the antenna cover for a mobile communication showing another embodiment of the present invention

7 is a measurement orientation of wind load in the antenna cover

Figure 8 illustrates the conditions of the comparative example for the wind tunnel experiment of the present invention

Figure 9 is a graph showing the wind tunnel test results in the embodiment of the present invention

10 is a perspective view of a model applied to the thickness and height characteristic test in the embodiment of the present invention

11 is a view showing the relationship between the thickness of the front cover and the first buffer in the embodiment of the present invention;

12 is a graph showing a low drag degree according to the thickness ratio of the cover and the wind speed conditions in the antenna cover having a cross-sectional structure of type 1 in the embodiment of the present invention

FIG. 13 is a graph showing drag reduction depending on a thickness ratio of a cover to a body and a wind speed condition in an antenna cover having a cross-sectional structure of type 2 in an embodiment of the present invention; FIG.

14 is a graph showing the drag reduction according to the thickness ratio of the cover and the wind speed conditions in the antenna cover having a cross-sectional structure of Type 3 in the embodiment of the present invention

15 is a drag comparison table of Type 1, Type 2, and Type 3 in the embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

23 antenna cover assembly 230 antenna body housing

240: front cover 250: upper cap

260: lower cap 241: front cover

232232a: housing side 233: housing rear

244,244a: first buffer part 235,235a: second buffer part

The present invention relates to an antenna for directional mobile communication for receiving a signal of mobile communication, and more particularly, to install an antenna of an antenna tower of a mobile communication base station installed on a rooftop of a city center or a base station steel tower installed in a suburban area. The present invention relates to an antenna cover for drag reduction type mobile communication having an improved structure that can reduce drag caused by a gust.

The antenna for mobile communication is designed to be easy to adjust and maintain the angle of the antenna according to the change of the radio wave environment, and it is suitable for the radio wave environment by attaching fixing brackets having semi-circular curved parts in contact with the outer circumference of the antenna pole. By simply manipulating the bolts, it is possible to adjust the angle at which the antenna is swiveled so that it is installed in a mobile communication base station on the roof of a city building or a tower for a base station near the city center.

Antennas installed on tall structures, such as rooftops or pylons of buildings, are more affected by wind than on the ground. Therefore, in case of a typhoon, a mobile communication antenna may cause a destruction or overturning of a communication tower in which a mobile communication antenna is installed, resulting in human physical damage. Moreover, in recent years, as the extreme weather phenomenon frequently occurs, the intensity of the gust is gradually increasing, and there is a need for structural improvement for the safety of the antenna for mobile communication against the typhoon and the gust.

1 is a perspective view of a conventional antenna for mobile communication, and FIG. 2 is a cross-sectional view of a conventional antenna body housing.

Referring to this drawing, a conventional antenna for mobile communication 1 includes an antenna pole 10 for installing an antenna and an antenna cover assembly 11 having a reflector for transmitting and receiving radio waves installed therein and fixed to the antenna pole 10. )Wow; An upper connection part 12 connecting the antenna pole 10 and the top of the antenna cover assembly 11 by at least two link members; The lower end portion of the antenna cover assembly 11 is rotatably fixed to the antenna pole 10.

Here, the antenna cover assembly 11 has side surfaces 111 and 111a formed at right angles from both ends of the front surface 110 that are planar as shown in FIG. 2, and are side by side parallel to the front surface 110. The end portion of the a) is formed by the rear surface 113 is connected, in order to reduce the drag caused by the air resistance, the corner portion is connected to the front surface 110 and the side surfaces (111, 111a) is formed with curved surfaces 112, 112a It protects the antenna element installed inside.

The antenna of FIG. 1 introduces an example of a conventional antenna, and there are antennas having different shapes from those of the antenna illustrated in FIG. 1, and are designed to minimize drag acting on the front surface due to wind pressure.

Since the antenna cover assembly 11 is installed on a high structure such as a rooftop or a steel tower of a building, and thus is more affected by wind than on the ground, the antenna cover assembly 11 is always at risk of deforming or overturning.

In general, fluid flowing on the curved surface of an object impinges on the surface and flows at an angle so that acceleration occurs at the curved portion. Therefore, the flow velocity just outside the boundary layer at the curved surface is minimal, and the pressure gradient from the curved surface where the flowing fluid begins to directly contact the outermost surface becomes negative, and the force due to the forward pressure acting on the fluid at the boundary layer It acts in the flow direction. These pressure gradients appear to be of significant magnitude and are less likely to form on a plate with a pressure gradient of zero. That is, as the flow velocity on the surface becomes larger than the plate on which the fluid acts, the drag on the object appears smaller on the surface than on the plate.

From the end of the curve, the fluid no longer flows along the surface, resulting in flow and backflow due to the decrease in velocity at the boundary layer. It is greatly disturbed by the large vortex, where the pressure decreases and the pressure drag acting on the object increases.

 In the conventional antenna cover assembly 11 shown in FIGS. 1 and 2, the fluid flowing on the curved surfaces 113 and 114 flows at an angle to the surface, so that the drag acts on the antenna cover assembly 11 while accelerating in the curved portion. In the front surface 110 formed in a flat shape, the flow velocity acts at right angles, and the energy of wind pressure acting on the front surface 110 acts as a drag of the antenna cover assembly 11.

That is, the wind pressure acting on the antenna cover assembly 111 by the typhoon or the gust of wind forms the backflow and the wake while passing through the side surfaces 111 and 112, and the drag acting on the front surface 110 and the side surfaces 111 and 112 and the rear surface 113. Backflow and wake occurring in the rear space of the antenna cause vibration and deformation of the antenna cover and the connection structure of the steel tower, causing local destruction or overturning.

As a protection method for a mobile communication antenna in the conventional mobile communication tower, such a method is used to reinforce a structure such as a support line, or to install a weight on the bottom, but these methods are additionally expensive. in need.

In order to reduce the drag on the antenna body housing, a structure is proposed in which the front surface is formed into a completely curved surface, but this is caused by an acceleration in the wind speed flowing through the curved surface formed on the front surface, which causes a large vortex in proportion to the wind speed on the back side. It was not possible to effectively prevent vibration by

In order to reduce the vortices occurring in the rear side, it may be considered to form a streamlined rear portion, but this structure can reduce drag against the wind pressure and wind speed acting on the front side, but when the wind pressure and wind speed act on the side, It is not desirable that greater drag is generated.

The antenna for mobile communication should be able to be manufactured at low cost to enable mass production with structural stability, and it should not be caused by drag and vortex caused by wind pressure from the basic structure of the current antenna rather than reinforcement design of materials or additionally installed facilities. Pulsation should be reduced.

To realize this, it is necessary to structurally improve the linearity of the antenna body housing so that the antenna can fundamentally reduce drag at a minimum cost.

The present invention provides an additional linear structure from the structure of the existing antenna to reduce drag by improving the linearity of the antenna, which is the main cause of the destruction of the steel tower on which the mobile communication antenna is installed, thereby reducing drag caused by wind pressure. will be.

The linear criterion of the antenna having a drag more favorable than the current structure with respect to the wind pressure can be determined by the drag measurement against the wind acting on the front of the antenna body housing which receives the most wind pressure. It is intended to achieve its intended purpose by improving

In order to achieve the intended purpose of the present invention, due to the rapid development of mobile communication technology and services, rather than manufacturing and replacing a new linear antenna that can reduce drag due to wind pressure in a situation where many antennas are already installed. In order to reduce the drag due to wind pressure by improving the linearity of the antenna by installing a structure that can reduce drag against the antenna installed in the antenna, it is possible to quickly replace at a low cost to ensure safety from gusts.

Technical features for achieving the object of the present invention is that the front and side and the rear surface is formed in a substantially rectangular cross-section formed in the antenna element is installed inside, the antenna pole by the link member to adjust the direction angle and inclination angle In forming the antenna body housing of the mobile communication antenna that receives the mobile communication signal from the mobile communication base station rotatably installed on the roof of the building or the base station tower installed near the downtown, the front of the antenna body housing and The first buffer part and the second buffer part are continuously formed on both sides of the side surfaces, and the first buffer part and the second buffer part are formed like the outer shape of the antenna main body housing to accommodate the upper end and the lower end of the antenna main body housing, respectively. It characterized in that it comprises an upper cap and a lower cap.

In the present invention, the first shock absorber and the second shock absorber may be integrally formed in one antenna body housing, and the first shock absorber may be formed separately on the front surface of the existing antenna body housing including the shock absorber. The front cover is attached so that the first buffer portion and the second buffer portion are continuously formed.

In the antenna cover of the present invention as described above, the wind acting on the front surface of the front cover covers the first shock absorbing portion, and the drag is primarily attenuated. As the drag decreases, the wind speed increased at the boundary of the first shock absorbing portion is the antenna body housing. The wind speed is reduced at the beginning of the second buffer when passing through the second buffer, and then the drag is secondarily attenuated and moved through the side while passing through the second buffer. Due to the wind speed, less vortex is formed at the rear of the rear surface, thereby reducing vibration.

Such an embodiment of the present invention will be described with reference to the accompanying drawings.

3 to 5 show drawings related to the first embodiment of the present invention.

The antenna 2 of the present invention referred to in FIG. 3 is composed of an antenna cover assembly 23 rotatably fixed to an upper connecting portion 21 and a lower connecting portion 22 installed in the antenna pole 20 as is well known. do.

The upper connection portion 21 is formed of a pair of fixing brackets 210 and link members 211 that are formed in a semi-circular curved portion in contact with the outer circumferential surface of the antenna pole 20, fixed to the upper portion of the antenna pole 20, One end of the link member 211 is fixed to the fixing bracket located in the front, and the other end is fixed to the upper portion of the antenna cover assembly 23 to complement the lower connecting portion 22, the antenna cover assembly 23 It is formed of a known structure that can adjust the direction angle of.

The lower connecting portion 22 is a pair of fixing brackets 220 fixed to the lower portion of the antenna pole 20 to form a semi-circular curved surface contacting the outer circumferential surface of the antenna pole 20, the fixing bracket located in front The lower portion of the antenna cover assembly 23 is pivotally fixed to form a known structure that can be adjusted to the direction angle of the antenna cover assembly 23 in conjunction with the upper connection portion 21.

The antenna cover assembly 23 of the present invention is composed of an antenna body housing 230, a front cover 240, an upper cap 250, and a lower cap 260 as referred to in FIGS.

The antenna body housing 230 is formed of a front surface 231, a housing side surface 232, 232a, and a housing rear surface 233 having a predetermined thickness and having a hollow shape, and an edge between the front surface 231 and the housing housing side surfaces 232, 232a. Second buffer parts 235 and 235a which are curved surfaces are formed in the site.

The front cover 240 is formed of a cover front surface 241, cover side surfaces 242 and 242a, and a cover rear surface 243 having a predetermined thickness and having a hollow shape, and an edge between the cover front surface 241 and the cover side surfaces 242 and 242a. The first buffer parts 244 and 244a having curved surfaces are formed in the portion and fixed to the antenna body housing 230.

The front cover 240 is formed of a hollow body by bending or drawing using thermoplastics of a synthetic resin-based material, or by forming a sponge, EVA, urethane, etc. into a non-porous body that becomes lightweight. You can also make.

The width W1 formed by the front cover 240 and protruding from the front surface 231 of the antenna body housing 230 including the first shock absorbing portions 244 and 244a is considered in consideration of wind acting on the side surface. It is preferable to have a dimension ratio corresponding to 35 to 50% of the width W2 formed by the 232 and 232a and the second buffer parts 235 and 235a.

The front cover 240 is formed in a variety of shapes according to the shape of the antenna body housing 230 that is previously manufactured, the cover back 243 is such as adhesive or screws on the front surface 231 of the antenna body housing 230 It may be fixed by a fastener, and if desired, the antenna body housing 230 and the front cover 240 may be integrally formed.

The upper cap 250 has an outer shape in which the antenna body housing 230 and the front cover 240 are coupled to accommodate the upper end of the antenna body housing 230 to which the front cover 240 is attached with a predetermined thickness. Thus formed.

The upper cap 250 is formed of the front surface 251, the side surfaces 252 and 252a, and the rear surface 253, and the first buffers 254 and 254a and the first buffer portions 254 and 254a are formed at corner portions between the front surface 251 and the side surfaces 252 and 252a. Two buffer parts 255 and 255a are continuously formed, and an upper portion of the upper portion 255 and 255a is formed so that the upper portion 255 and 255a may be covered by the antenna body housing 230 to which the front cover 240 is attached. Fixing pieces 257 and 257a for fixing to the link member 211 are formed.

The lower cap 260 has a predetermined thickness and follows an outer shape in which the front cover 240 and the antenna body housing 230 are combined to accommodate the lower end of the antenna body housing 230 to which the front cover 240 is attached. Is formed.

The lower cap 260 is formed of the front surface 261, the side surfaces 262 and 262a, and the rear surface 263, and the first buffers 264 and 264a and the first buffer portions 264 and 264a are formed at corner portions between the front surface 261 and the side surfaces 262 and 262a. The two buffer parts 265 and 265a are continuously formed, and an upper portion of the upper portion 265 and 265a is formed on the bottom surface 266 so as to be covered by the antenna body housing 230 to which the front cover 240 is attached. Fixing pieces 267 and 267a for fixing to the fixing bracket 220 are formed, and the bottom surface 266 is formed with a conventional cable inlet 268 through which a cable can pass.

In the present invention as described above, the front cover 240 is fixed to the front surface 231 of the antenna body housing or the antenna body housing 230 in which the front cover is integrally formed by using an adhesive or a fastener, and then the antenna element as in the conventional method. After installing in the antenna body housing 230, the upper cap 250 and the lower cap 260 is placed on the upper and lower portions of the antenna body housing 230, respectively, as shown in Figure 3 the upper cap 250 is When fixed to the link member 211, the lower cap 260 is fixed to the fixing bracket 220 is installed in a direction inclined with respect to the antenna pole 20 in accordance with the propagation characteristics.

The antenna body housing installed in this way generates a constant drag on the front surface due to the influence of the surface friction against the wind. As shown in FIG. 5, the airflow of the wind acting on the cover front surface 241 of the front cover 240 has both cover side surfaces. As the gas flowing on the surfaces of the first buffer parts 244 and 244a flows obliquely along the curved surface, the frictional resistance decreases primarily due to the acceleration in the curved portion. As the frictional resistance is secondarily reduced while flowing along the second buffer parts 234 and 234a of the cover 230, the drag acting on the antenna cover 230 is minimized while flowing along the side surfaces 232 and 232a of the cover 230. .

Here, the gas flowing in the curved portion generally forms a strong vortex in the rear space of the housing housing side surfaces 232 and 232a and the rear surface of the housing 233 while the flow velocity is increased. As the gas flows through the gas stream, the gas flows at a point where the second shock absorbers 235 and 235a start, and the flow velocity decreases to some extent, and then passes through the second shock absorbers 235 and 235a.

The flow of gas flowing through the first buffer portion 244, 244a and the second buffer portion 235, 235a with an appropriate flow rate forms a gentle flow curve at the rear side and the rear surface of the housing side surface 232, 23a. It is possible to significantly reduce the eddy current at the same time, and at the same time, it is also possible to significantly reduce the eddy current caused by the pressure drop at the rear of the housing rear surface 233, thereby reducing the drag force acting on the antenna cover 230 to reduce vibration. It is possible to prevent and keep the direction angle of the antenna constant.

In the above description, the action of the gas on the antenna cover 230 and the front cover 240, but the upper cap having the same shape as the outer shape of the antenna cover 230 and the front cover 240 is coupled In the first buffer portion 254, 254a, the second buffer portion 255, 255a, and the first buffer portion 264, 264a and the second buffer portion 265, 265a formed in the lower cap 260 at 250, respectively. The same drag reduction action.

The embodiment described above shows an example to which the present invention is applied, that is, an example in which the technical idea of additionally forming a front cover of a structure capable of reducing drag on the front surface of an antenna body housing that is already constructed in the prior art is realized. Of course, it can also be applied to a variety of linear antenna body housing that is installed.

6 is a cross-sectional view showing an embodiment in which the present invention is applied to an antenna body housing that has been previously installed with another linear shape.

In this embodiment, the first and second buffer parts 301 and 301a which are inclined from the front part 300 and the second buffer parts 302 and 302a which are curved surfaces are continuously formed. It is formed along the outer shape to act as a drag reduction action as described above.

Wind tunnel test results for testing the drag reduction action of the present invention are as follows.

7 illustrates a state in which wind load is applied to the antenna body housing.

Antennas are usually installed to be inclined to maintain an optimal radio wave reception condition, but the danger of the antenna is subjected to the maximum wind load in the vertical state of 90 °. In this experiment, the antenna is measured by standing up to 90 ° to measure the risk of the antenna. It was.

8 illustrates the conditions of the embodiment for the wind tunnel experiment.

Figure 9 shows a graph of the results of measuring the force acting on the overturn and destruction of the antenna with a six-component meter in the wind tunnel.

Where MY is the Y axis moment and X is the force about the X axis.

As described above, when the wind blows in the X direction, the moment acts in the (y, -y) direction. Therefore, the main force of the antenna's overturn and destruction is to determine the superiority by measuring the force generated on the X axis.

This graph shows that the force on the X axis is proportional to the moment on the Y axis.

The experimental sample of the conventional antenna reduces the conventional physical antenna to a quarter size, and as shown in FIG. 8, the angle θ of the first buffer part in the second embodiment of the present invention is 75 °, 60 °, The data on the change of behavior tested using the wind tunnel device for the comparative example of the antenna cover formed at 45 ° are shown in Table 1 below.

X direction (backward sliding) Y direction (left and right shake) Z direction (press from above) x direction (%) Force (average) Force (%) Conventional example Sum 12091 450.86 -1440.72 100 13982.58 100 Average 1.00758333 0.03757167 -0.12006 1.165215 Comparative Example 1 θ75 ° Sum 7215.06 1138.12 -960.12 59.673 9313.3 66.6064 Average 0.601255 0.09484333 -0.08001 0.776108 Comparative Example 2 θ60 ° Sum 7221.34 962.06 -960 59.7249 9143.4 65.3914 Average 0.60177833 0.08017167 -0.08 0.76195 Comparative Example 3 θ45 ° Sum 7514.32 1012.22 -1440 62.148 9966.54 71.2783 Average 0.62619333 0.08435167 -0.12 0.830545

The experiment was conducted at wind speeds of 18m / sec and 26m / sec, and the results of the experiment showed that the drag reduction was reduced by 30% or more at 18m / sec, and by 40% or more by 26m / sec. It was found that the reduction in drag could be increased.

As described above, the present invention significantly reduces the vortex and drag acting around the antenna cover by the wind pressure and the wind speed.

In order to apply the technical idea of the present invention to an antenna body housing manufactured with various linear shapes, three types of models illustrated in FIG. 10 using a wind tunnel are type 1 (A), type 2 (B), and type 3 ( For C), the characteristics were tested by thickness and height to obtain optimum performance.

Here, the specification of the wind turbine is 12.5m / sec at 25hz, 21m / sec at 40hz, 26m / sec at 50hz.

11 shows the relationship between the thickness of the front cover and the first buffer part in the embodiment of the present invention. As referred to in this figure, it is preferable that the width Y of the first cushioning portion is 60 to 80% of the thickness X of the front cover.

In the antenna cover having a cross-sectional structure of Type 1 (A), a comparison graph of the thickness ratio of the cover to the body according to the wind speed condition is shown in FIG. 12, and the comparison table is shown in Table 2 below. The test result shows that the drag is reduced by 48% at 26m / sec wind speed, and the sudden drag difference appears as the wind speed increases.

Wind speed 0% 25% 35% 45% 50% 55% 60% 25hz 0.237 0.212 0.203 0.194 0.175 0.186 0.178 40hz 0.607 0.533 0.465 0.406 0.413 0.413 0.386 50 hz 0.965 0.746 0.641 0.619 0.617 0.610 0.599

In the antenna cover having the cross-sectional structure of Type 2 (B), a comparison graph of the thickness ratio of the cover to the body according to the wind speed condition is shown in FIG. 13, and the comparison table is shown in Table 3 below. As a result of the test, the drag decreased by 28% at 26m / sec wind speed.

Wind speed 0% 25% 45% 50% 55% 60% 25hz 0.2021 0.1585 0.1573 0.1560 0.1556 0.1477 40hz 0.5755 0.4270 0.4191 0.4142 0.4120 0.4096 50 hz 0.9133 0.6879 0.6781 0.6660 0.6643 0.6614

In the antenna cover having a cross-sectional structure of Type 3 (C), a comparison graph of the thickness ratio of the cover to the body according to the wind speed condition is shown in FIG. 14, and the comparison table is shown in Table 4 below. As a result of the test, the drag decreased 41% at 26m / sec wind speed.

Wind speed 0% 25% 35% 45% 50% 55% 25hz 0.2529 0.1627 0.1723 0.1599 0.1585 0.1505 40hz 0.6595 0.4111 0.3960 0.3913 0.3863 0.3848 50 hz 1.0263 0.6599 0.6335 0.6285 0.6160 0.6130

Fig. 15 is a graph comparing the drag of the front cover to the antenna cover body of the model having the cross-sectional structures of Type 1 (A), Type 2 (B) and Type 3 (C), and the comparison table is shown in Table 5 below. same.

Sectional Structure 0% 35% 45% 50% 55% 60% Type 1 0.9646 0.6414 0.6189 0.6166 0.6105 0.5989 Type 2 0.9133 0.6879 0.6781 0.666 0.6643 0.6614 Type 3 1.0263 0.6599 0.6335 0.6285 0.616 0.613

The present invention is to significantly reduce the vortex and drag acting around the antenna cover by the wind pressure and wind speed, while forming a visually beautiful pattern or design pattern and image on the outer surface of the antenna cover and the surrounding environment of the city It can provide an eco-friendly antenna for mobile communication that can go well with the natural environment.

The antenna cover for mobile communication of the present invention is to prevent the gust caused by the typhoon or extreme weather due to the improved structure that the first shock absorber and the second shock absorber can reduce the drag caused by the wind by appropriately adjusting the speed of the air flow. It is possible to provide stability to prevent personal damage caused by destruction or overturning of communication towers, and there is no change in the propagation characteristics due to no change in antenna orientation angle due to wind pressure, so that the reliability of radio wave quality of mobile communication service can be improved. I can give it.

Claims (7)

It is formed in the same cross-sectional shape as the outer shape of the antenna cover and has an upper cap and a lower cap for receiving the upper and lower portions of the antenna cover, respectively, and the buffer portion is formed in a curved surface at the corner portion where the front and side are connected In the antenna cover for mobile communication to reduce the air resistance to protect the antenna for transmitting and receiving radio waves, The antenna cover for drag reduction type mobile communication, characterized in that the buffer portion is further formed on the front surface of the antenna cover so that the first buffer portion and the second buffer portion are continuously formed in two stages at both front and side boundary portions of the antenna cover. The antenna cover for drag reduction type mobile communication according to claim 1, wherein the first buffer part is formed in a curved surface. The antenna cover for drag reduction type mobile communication according to claim 1, wherein the first buffer portion is formed in a plane having an inclination angle. 4. The antenna cover for drag reduction type mobile communication according to any one of claims 1, 2 and 3, wherein a front cover having a first buffer unit is attached to a front surface of an existing antenna cover having a buffer unit. The antenna cover for drag reduction type mobile communication according to any one of claims 1, 2 and 3, wherein the first shock absorber and the second shock absorber are integrally formed in one antenna cover. 4. The drag reduction type mobile communication device according to any one of claims 1, 2 and 3, wherein the width Y of the first buffer part is 60 to 80% of the thickness X of the front cover. Antenna cover. delete

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