Patent Description:
Various communication systems based on wireless technologies such as cellular communication, radio broadcasting, GPS (Global Positioning System) are being developed. In order to deal with these communication systems, an antenna capable of transmitting and receiving electromagnetic waves used for each communication system is required.

In recent years, with miniaturization, antennas are increasingly installed in buildings. A large number of antennas are installed in the building so that electromagnetic waves used for mobile communications can be transmitted and received in a stable manner. When installing the antenna in the building, it is necessary to select the proper placement of the antenna so that electromagnetic waves can be transmitted and received stably while preventing the appearance of the building from being impaired.

In addition, in order to increase the speed and capacity of wireless communication, frequency bands to be used are becoming higher, like the frequency bands for the 5th generation mobile communication system (<NUM>). Therefore, even if a high-frequency electromagnetic wave having a broadband frequency band is used for a mobile communication, etc., it is necessary to install a larger number of antennas in order to stably perform electromagnetic wave transmission and reception.

As an antenna unit to be installed and used in a building, for example, there are three layers having different relative dielectric constants, each layer is set to a predetermined thickness, and a radio wave transmitting body as described in the patent application <CIT>.

However, according to the technique described in <CIT>, there is a case where the temperature of the first layer excessively rises when the sunlight hits the first layer, depending on the installation place or the installation condition of the antenna unit and the like, It has not been studied that there is a possibility of thermal cracking in the first layer of the permeable member. <CIT> disclose a glazing unit comprising a glass panel and an antenna.

An object of one embodiment of the present invention is to provide a glass antenna unit capable of reducing the possibility of occurrence of thermal cracking in a glass panel while the back radiation of the waves from the structure due to reflection from the glass panel has to be minimized.

It is an object of the present invention to alleviate these problems, and to provide a glazing unit which reduces the reflection of the waves radiated by the antenna from the glass panel while reducing the possibility of occurrence of thermal cracking in the glass panel.

According to a first aspect of the invention, the invention relates to an improved glazing unit according to claim <NUM>.

Optional features are laid down in the dependent claims.

The following description relates to an building window unit but it's understood that the invention may be applicable to others fields like transportation windows which have to be attached such as train.

<FIG>, <FIG> are embodiments according to the claimed invention. <FIG> do not include all the features of the independent claim and, therefore, relate to examples not forming part of the claimed invention.

For a better understanding, the scale of each member in the drawing may be different from the actual scale. In the present specification, a three-dimensional orthogonal coordinate system in three axial directions (X axis direction, Y axis direction, Z axis direction) is used, the width direction of the glass panel is defined as the X direction, the thickness direction is defined as the Y direction, and the height is defined as the Z direction. The direction from the bottom to the top of the glass panel is defined as the + Z axis direction, and the opposite direction is defined as the - Z axis direction. In the following description, the + Z axis direction is referred to as upward and the - Z axial direction may be referred to as down.

With reference to <FIG>, a first embodiment of the present invention is described.

As shown in <FIG>, a glazing unit <NUM> extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Z; having a width, W, measured along the longitudinal axis, X, and a length, L, measured along the vertical axis, Z, comprises a glass panel <NUM> and an antenna unit <NUM>. The antenna unit <NUM> is attached to the main surface on the indoor side of the glass panel <NUM>. Then, sunlight or the like is irradiated on the main surface of the glass panel <NUM> on the side opposite to the interior side.

In some embodiments, the glass panel comprises at least one glass sheet.

In some preferred embodiments, the glass panel comprises at least two glass sheets separated by a spacer allowing to create a space filled by a gas like Argon to improve the thermal isolation of the glass panel, creating an insulating glazing panel. It means that, in these embodiments, the antenna unit is placed outside of the insulating glazing panel on the glass face the most far from the outside face where the sun is directly heating.

The glass panel <NUM> is a known glass plate used for a window of a building or the like. The glass panel <NUM> is formed in a rectangular shape in plan view and has a first main surface and a second main surface. The thickness of the glass panel <NUM> is set according to requirements of buildings and the like.

In some embodiments, the first main surface of the glass panel <NUM> is set to the outdoor side and the second main surface is set to the indoor side (facing the antenna <NUM>).

In the present embodiment, the first main surface and the second main surface are collectively referred to simply as the main surface in some cases. In the present embodiment, the rectangle includes not only a rectangle or a square but also a shape obtained by chamfering corners of a rectangle or a square. The shape of the glass panel <NUM> in a plan view is not limited to a rectangle, and may be a circle or the like. Further, the glass panel <NUM> is not limited to a single plate, and it may be a laminated glass or a double-layered glass.

In another embodiment, the glass panel can be a laminated glass panel to reduce the noise and/or to ensure the penetration safety. The laminated glazing comprises glass panels maintained by one or more interlayers positioned between glass panels. The interlayers employed are typically polyvinyl butyral (PVB) or ethylene-vinyl acetate (EVA) for which the stiffness can be tuned. These interlayers keep the glass panels bonded together even when broken in such a way that they prevent the glass from breaking up into large sharp pieces.

As the material of the glass panel <NUM>, for example, soda-lime silica glass, borosilicate glass, or aluminosilicate glass can be mentioned.

The glass panel <NUM> can be manufactured by a known manufacturing method such as a float method, a fusion method, a redraw method, a press molding method, or a pulling method. As a manufacturing method of the glass panel <NUM>, from the viewpoint of productivity and cost, it is preferable to use the float method.

The glass panel <NUM> can be formed in a rectangular shape in a plan view by using a known cutting method. As a method of cutting the glass panel <NUM>, for example, a method in which laser light is irradiated on the surface of the glass panel <NUM> to cut the irradiated region of the laser light on the surface of the glass panel <NUM> to cut the glass panel <NUM>, or a method in which a cutter wheel is mechanically cutting can be used.

The glass sheet can be a clear glass or a coloured glass, tinted with a specific composition of the glass or by applying a coating or a plastic layer for example.

In order to minimize the heat inside the building and inside the space S between the antenna <NUM> and the glass panel <NUM>, the glass panel <NUM> may be provided with a coating layers system having a heat ray reflecting function and the like on the second main surface on the interior side of the glass panel <NUM>.

In this embodiment, the coating layers system preferably has an opening at a position facing the antenna unit of the antenna unit <NUM>. Thereby, the glass panel with an antenna can suppress deterioration of the radio wave transmission performance.

The opening can be a surface without the coating layers system or a plurality of small slits or any shape in the coating layers system to become a frequency selective surface in order to let waves pass from one side to the other side of the glass panel and can further suppress deterioration of radio wave transmission performance.

As the coating layers system, for example, a conductive film can be used. As the conductive film, for example, a laminated film obtained by sequentially laminating a transparent dielectric, a metal film, and a transparent dielectric, ITO, fluorine-added tin oxide (FTO), or the like can be used. As the metal film, for example, a film containing as a main component at least one selected from the group consisting of Ag, Au, Cu, and Al can be used.

The glass sheet can be processed, ie annealed, tempered,. to respect with the specifications of security and anti-thief requirements. A heatable system, for example a coating or a network of wires, can be applied on the glazing unit to add a defrosting and/or a demisting function for example.

In case of several glass sheets, in some embodiments, each glass sheet can be independently processed and/or coloured,. in order to improve the aesthetic, thermal insulation performances, safety,.

As shown in <FIG>, the antenna unit <NUM> comprises a fixing portion 13A for fixing the antenna <NUM> to the glass panel so that a space S through which air can flow is formed between the glass panel <NUM> and the antenna <NUM>.

The antenna unit <NUM> further comprises at least one non-fixing portion and at least one metallic element <NUM> placed over at least a part of the non-fixing portion of the antenna unit <NUM>.

In addition, the glazing unit <NUM> can be assembled within a frame or be mounted in a double skin facade or any other means able to maintain a glazing unit.

According to some embodiments according to the invention, the antenna <NUM> can be a flat plate-like substrate on which the antenna <NUM> is provided. For instance, the antenna <NUM> can be a planar antenna like the microstrip patch array, slot array, a dipole antenna, an array of antennas, or the like can be used.

As the metal material forming the antenna <NUM>, a conductive material such as gold, copper, nickel or silver can be used.

According to the invention, the antenna <NUM> may radiate in the direction of outside (+Y), meaning to the direction of the glass panel, in the direction of inside (-Y), meaning to the opposite direction of the glass panel or in both directions (+Y, -Y).

In some embodiments, the antenna <NUM> can be provided on a first main surface of the antenna installation substrate. The antenna <NUM> can be formed by printing a metal material so as to at least partially overlap a ceramic layer provided on the second main surface of the antenna installation substrate. In that embodiment, the antenna <NUM> is provided on the second main surface of the antenna installation substrate so as to straddle the portion where the ceramic layer is formed and the other portion.

In this embodiment, the ceramic layer can be formed on the second main surface of the antenna installation substrate by a known method such as printing. By providing the ceramic layer, the wiring (not shown) attached to the antenna <NUM> can be covered or hidden to have a better finish and/ or design. Further, in the present embodiment, the ceramic layer is formed on the first main surface but may not be provided.

In the present embodiment, the antenna <NUM> is provided on the first main surface of the antenna installation substrate, but may be provided inside the antenna installation substrate. In this case, for example, the antenna <NUM> can be provided inside the antenna installation board in the form of a coil. Further, the antenna <NUM> itself may be formed in a flat plate shape. In this case, instead of using the antenna mounting board, a flat plate antenna may be directly attached to the fixing portion 13A. The antenna <NUM> may be provided inside the accommodation container having a surface parallel to the glass panel <NUM>, in addition to being provided on the antenna installation substrate <NUM>. In this case, in the antenna <NUM>, for example, a flat antenna can be provided inside the storage container.

The antenna <NUM> preferably has optical transparency to be has discrete as possible. If the antenna <NUM> has optical transparency, the average solar radiation absorption rate can be lowered on top of the hidden effect.

Preferably, the antenna <NUM> or the antenna installation substrate is provided in parallel to the glass panel <NUM>. The antenna <NUM> or the antenna installation substrate can be formed in a rectangular shape in a plan view and has a first main surface and a second main surface. The first main surface is provided so as to face the main surface of the glass panel <NUM> to be attached and the second main surface is provided in a direction opposite to the main surface side of the glass panel <NUM>.

In some embodiments, the material for forming the antenna installation board is designed according to the antenna performance such as power and directivity required for the antenna <NUM>, and for example, glass, resin, metal, or the like can be used. The antenna installation substrate may be formed to have light transmittance by resin or the like. Since the antenna mounting board <NUM> is made of a light transmissive material, the glass panel <NUM> can be seen through the antenna installation board <NUM>, so that it is possible to reduce the obstruction of the field of view seen from the glass panel <NUM>.

The thickness of the antenna installation board can be designed according to the place where the antenna <NUM> is arranged.

The fixing portion 13A is for forming a space S through which air can flow between the glass panel <NUM> and the antenna <NUM> and is for fixing the antenna <NUM> to the glass panel <NUM>. The fixing portion 13A is attached to the first main surface of the antenna installation substrate <NUM>. In the present embodiment, the fixing portion 13A is provided in a rectangular shape along the Z-axis direction at both ends in the X-axis direction of the antenna installation substrate. In the present embodiment, the reason why the space S through which air flows is formed between the glass panel <NUM> and the antenna <NUM> is that the local temperature of the surface temperature of the glass panel <NUM> at the position facing the antenna <NUM>. When the outer main surface of the glass panel <NUM> is irradiated with sunlight, the glass panel <NUM> is heated. At this time, if the flow of air is blocked in the vicinity of the antenna unit <NUM>, the temperature of the antenna unit <NUM> rises, so that the temperature of the surface of the glass panel <NUM> to which the antenna unit <NUM> is attached is higher than the temperature of the other surface The temperature tends to rise more easily. In order to suppress this temperature rise, a space S is formed between the glass panel <NUM> and the antenna <NUM>. Details regarding this point will be described later.

The material for forming the fixing portion 13A is not particularly limited as long as it can be fixed to the contact surface of the antenna <NUM> and the glass panel <NUM>. For example, an adhesive or an elastic seal can be used. Materials for forming adhesives and sealing materials.

The average thickness t of the fixing portion 13A is preferably <NUM> to <NUM>. If the average thickness t is too small, the thickness of the space S formed by the antenna <NUM> and the glass panel <NUM> becomes small (thin), and the air does not smoothly flow through the space S. By making the space S between the antenna <NUM> and the glass panel <NUM> slight, the thickness of the space S becomes thin, but the space S can function as a heat insulating layer. Even if the thickness of the space S is small, a certain amount of air flows. That is, when sunlight is irradiated on the glass panel <NUM>, the temperature of the glass panel <NUM> rises, and the temperature of the air in the space S also rises. As the temperature of the air rises, the air expands more, so that the upper air in the space S rises and flows out from the upper side of the space S to the outside. Then, the air sequentially rises from the lower side in the space S. Therefore, even when the thickness of the space S is small, the air tends to flow as the temperature of the air in the space S rises.

On the other hand, when the average thickness t of the fixing portion <NUM> A is increased, the space S is increased (thickened) by that much, so that the air flow in the space S is preferable. However, since the distance between the main surface of the glass panel <NUM> and the antenna <NUM> increases (increases), there is a possibility that the electromagnetic wave transmission performance may be hindered. Further, since the antenna unit <NUM> protrudes largely from the main surface of the glass panel <NUM>, the antenna unit <NUM> becomes an obstacle to the glass panel <NUM>.

Although the embodiment in which the fixing portion <NUM> A is provided at two locations of the antenna <NUM> has been described so far, the mode of the fixing portion 13A is not limited as long as the air can flow in the space S. An example of another form of the fixing portion 13B. As is shown in <FIG>,. the fixing portion can have another form. According to the invention, the fixing portion 13B is provided at both ends in the X-axis direction of the first main surface of the antenna <NUM> and at both ends in the Z-axis direction, respectively, and the antenna <NUM> is fixed to the glass panel with four fixing portions Further, among the four fixing portions 13B, only one fixing portion <NUM> B provided in the -Z axis direction is provided at the lower end of the antenna installation substrate <NUM>, for example, near the center, and the antenna installation substrate <NUM> is fixed to the glass panel <NUM> by three It may be fixed by the portion 13B. It is understood that a plurality of small fixing elements can be used instead of long fixing elements as shown in <FIG>.

When the average thickness t of the fixed portion 13A is within the above range, the air flowing into the space S can pass through the space S due to a slight increase in temperature. As a result, the glass panel <NUM> can be prevented from being heated by the air flowing in the space S, so that excessive temperature rise of the antenna <NUM> can be suppressed. The average thickness t of the fixing portion 13A is more preferably <NUM> to <NUM>, further preferably <NUM> to <NUM>, and particularly preferably <NUM> to <NUM>.

In the present embodiment, the thickness refers to the length in the vertical direction (Y axis direction) of the fixed portion 13A with respect to the contact surface of the antenna <NUM> and the glass panel <NUM>. In the present embodiment, the average thickness t of the fixed portion 13A is an average value of the thickness of the fixed portion 13A. For example, when measured in several places (for example, about three places) at an arbitrary place in the Z axis direction in the cross section of the fixed part 13A, it means the average value of the thicknesses of these measurement points.

As described above, the space S is formed between the glass panel <NUM> and the antenna <NUM> by the fixing portion 13A and allows air to flow. Therefore, the thickness of the space S is substantially the same as the average thickness t of the fixed portion 13A.

In the antenna unit <NUM>, air flows into the space S from the lower side (-Z axis direction) of the antenna <NUM>. The air flowing into the space S can freely flow in the space S toward the upper side (+ Z axis direction) of the antenna <NUM>. The air flowing through the space S flows out from the upper side (+ Z axis direction) of the antenna <NUM> while contacting the main surface of the glass panel <NUM> at a position facing the antenna <NUM>. By contacting the air in the space S with the main surface of the glass panel <NUM> at a position facing the antenna <NUM>, the main surface of the glass panel <NUM> at the position facing the antenna <NUM> is exposed to outside air and the sun excessive temperature rise due to light etc. is suppressed. In addition, since the fixing portion 13A is continuously formed in the vertical direction, the temperature difference between the upper portion and the lower portion in the space S is increased accordingly. Therefore, due to the so-called chimney effect, the flow velocity of the air flowing in the space S can be increased.

In the antenna unit <NUM>, a fixing portion <NUM> A is provided on the antenna <NUM> so that a space S through which air can flow is formed between the glass panel <NUM> and the antenna <NUM>. Thus, even if the glass panel <NUM> is heated by outside air, sunlight, or the like, excessive temperature rise of the main surface of the glass panel <NUM> at the position facing the antenna <NUM> can be suppressed. Therefore, it is possible to reduce the possibility of occurrence of thermal cracks in the glass panel <NUM> at the position facing the antenna <NUM>. Therefore, the antenna unit <NUM> can be stably installed on the glass panel <NUM> without causing damage to the glass panel <NUM>.

The non-fixing portion is portion of the antenna unit not in contact with the glass panel <NUM> allowing the air to flow though compared to the fixing portion.

In some embodiments, the fixing portion can let air flows by using holes, small elements instead of large ones.

According to the invention, the metallic element <NUM> allows the level of back radiation of the wave of the antenna <NUM> on the glass panel <NUM> to be decreased since the metallic element <NUM> prevents the reflection from the glass panel <NUM> scattered behind the antenna <NUM> while allowing the air flow, at least inside the space S.

The metallic element can be a metal-based element, an element with a core and surfaces where at least the surface in front of the space S is metalized. In some embodiment, the metallic element is a metal coated plastic element.

Material used for the metallic element may be a high conductive material such as Cu, Ag, Al, or mix of metal to minimize the back radiation.

It is understood that the surface of the metallic element depends on the dimensions of the antenna unit.

The metallic element <NUM> has two majors surfaces 11A, 11B where one is in front of space S.

Preferably, the metallic element <NUM> is a plate with one of these majors surface 11A is in front with the space S and the other major surface 11B is slightly parallel to the major surface in front of space S.

Preferably, the thickness of the metallic element is at least two times the skin depth of the metallic material used in the metallic element on the desire frequency in order to minimize the back reflection on the glass panel.

In some embodiments of the invention, the metallic element can be over the entire of at least one non-fixing portion to minimize the back reflection on the glass panel. Preferably, the metallic element cover the antenna at least near the non-fixing portion covered by the metallic element.

The antenna unit <NUM> is preferably provided at a position separated from the glass panel <NUM> by a predetermined distance L or more in plan view. The predetermined distance L is preferably <NUM>. For example, when the glass sheet is directly exposed to the sunlight, the temperature of the glass panel <NUM> rises to a high temperature. In some cases, there is a possibility that thermal cracks may occur in the portion of the glass panel or the vicinity thereof located at the position facing the antenna unit <NUM>. In particular, by attaching the antenna unit <NUM> to the second main surface of the glass panel <NUM>, the flow of air on the second main surface of the glass panel <NUM> at a position facing the antenna unit <NUM> is hindered. In this case, the temperature of the portion of the glass panel <NUM> located opposite the antenna unit <NUM> is further increased. As a result, there is a possibility that the thermal distortion occurring in the portion of the glass panel <NUM> at the position facing the antenna unit <NUM> or in the vicinity thereof may be further increased.

The predetermined distance L is more preferably <NUM>, further preferably <NUM>, particularly preferably <NUM>, most preferably <NUM>.

In some embodiments according to the invention, even if the temperature of the portion of the glass panel <NUM> located opposite the antenna unit <NUM> is increasing, and the metallic elements cover all non-fixing portions, the air flows inside de space S is enough to not increase to much. Metallic elements can be used as energy dissipater on top of reducing back reflection of the glass panel.

According to the invention and as shown in <FIG>, to dissipate more heat, the antenna unit has at least one hole in order to facilitate to air flow inside the space S.

The at least one hole <NUM> pierces the metallic element <NUM> from the major surface 11A in front of space S to the opposite major surface 11B in order to ensure the air flow from the space S to outside of the antenna unit <NUM>.

The at least one hole <NUM> can have any shape, such as cylindrical-shape, rectangular parallelepiped shape, macaroni-like shape or corkscrew shape or any other shape able to maximize the air flow from space S to outside of the antenna unit <NUM>, along the Z axis in the case of major surfaces of the metallic element <NUM> are in the X-Y plan.

The at least one hole <NUM> can be oriented with a certain angle from the Z axis in any direction in the case of major surfaces of the metallic element <NUM> are in the X-Y plan or any other orientation as far as the at least one hole pierces the majors surfaces (11A, 11B) of the metallic element.

<FIG>, according to some embodiments of the present invention, show an antenna unit <NUM> in a general form of a rectangular parallelepiped. It is understood that the shape of the antenna unit can have any other shape or design as long as there is a space S between the antenna <NUM> and the glass panel <NUM>.

In these schematically representation of the invention, the fixing portion comprises two fixing elements placed symmetrically on borders of the antenna12 as for <FIG>. The antenna unit <NUM> comprises two metallic elements <NUM> placed over the non-fixing portions.

Preferably, the metallic element <NUM> is over the entire surface of the non-fixing portion where the metallic elements <NUM> is over, and more preferably the metallic element <NUM> is over the antenna <NUM>.

To maximize the air flow, it is better to withdraw the metallic element in the other hand to minimize the back reflection of the waves, the metallic element has to cover the maximum of the space S. The present invention solves this problem by optimizing the air flow and in the same time minimizing the back reflection of the glass panel <NUM>.

Surprisingly, adding at least one hole to the metallic element allows to solve this problem.

According to embodiments, at least one hole is on the metallic element <NUM>. Other embodiments explained here under can be combined with these embodiments in order to have several holes for example.

According to the invention and as shown in <FIG>, one of the metallic elements has a hole <NUM> to let air flows and to facilitate the dissipation of heat.

As shown in <FIG>, to improve the dissipation of heat, one of the metallic elements has at least two holes <NUM>, and preferably several holes <NUM>.

The hole or holes <NUM> pierce the metallic element <NUM>. Holes can have any shape as far as air can flow thought. Some limitations can be made depending of materials used for the metallic element and also the process of manufacture.

Holes can be placed at several places in the metallic element in order to maximize the air flow. In case of metallic element along the X axis with the thickness in Z axis, holes are in the Z-axis but could oriented meaning that the surface of the hole on the top surface of the metallic element.

Preferably and as shown in <FIG>, on metallic element <NUM> can have several holes while a second metallic element has one hole. This configuration allows a good air flow through the space S. More preferably, to ensure an important air flow, the metallic element placed at the top of the antenna unit, meaning at the higher +Z, has more holes that the lower metallic element as shown in <FIG>.

As shown in <FIG>, metallic elements can have one hole on each or several holes on each. Size, dimensions, design and number of holes can be adapted to maximize the air flow through the space S. For example, a larger hole on the higher metallic element.

In case of metallic elements are placed on the X axis of the antenna unit, according to the invention, all these embodiments with at least one hole can be adapted.

In order to improve the air flow by minimizing the back reflection of the glass panel, preferably and as shown in <FIG>, the at least one metallic element <NUM> further comprises at least a meshed portion <NUM> corresponding with the space S of the antenna unit <NUM>. The meshed portion <NUM> can be understand as a plurality of small holes <NUM>.

Preferably, the largest dimension of the at least one hole may not be larger than <NUM> times the effective wavelength and preferably the largest dimension of every hole of the metallic element may not be larger than <NUM> times the effective wavelength. This wavelength is normalized to effective permittivity of the interface on which metallic structure is placed. In the present invention, as interfaces are air to air, the effective permittivity is <NUM>. The above formula about the maximum dimension of the aperture of the hole (<NUM> times the effective wavelength) remains valid in case of several holes and meshed portion.

The size of the meshed portion <NUM> as the dimensions of small holes <NUM> that composed it can be adapted to situations as frequencies to minimize in term of back reflection as air flow rate needed to drop the overheat.

Preferably, in some embodiments, the meshed portion has holes with square surface. Dimensions of squares are linked to the cut-off frequencies to minimize the back reflection of the glass panel.

As shown in <FIG>, in case of several metallic elements, one of the metallic elements <NUM> can have a meshed portion <NUM> and another metallic element <NUM> can have one hole <NUM>, several holes <NUM> or a meshed portion <NUM> in order to maximize the air flow by minimizing the back reflection of the glass panel.

In a preferred embodiment, metallic elements <NUM> of the antenna unit <NUM> cover the entire surface of the non-fixing portion and the antenna <NUM>. Metallic elements <NUM> of the antenna unit <NUM> have a meshed portion on this entire surface.

In a preferred embodiment according to the invention, as shown in <FIG>, fixing portion comprises small fixing elements. Metallic elements cover the entire surface of the non-fixing portion to minimize the back reflection of the glass panel.

In this embodiment, some metallic elements can have at least a hole. Preferably, at least two metallic elements have meshed portion and more preferably all metallic elements have a meshed portion.

Another way to have an better air flow by minimizing the back reflection according to the invention, is to place at least one hole on the fixing portion or the fixing portion comprises small fixing elements instead of one large one in order to let the air flows between these fixing elements and/or inside the at least one hole.

In some embodiments, metallic element can also covers fixing portion to minimize more the back reflection and/or fixing portion can be metallized to create a metallic element on it.

As shown in <FIG>, the normalized back radiation ([dB] - solid curve) of an glazing unit with an antenna unit without metallic element is higher than normalized back radiation ([dB] - dashed curve) of an glazing unit with an antenna unit with at least one metallic element where Theta ([Deg]) represents the angle between the Z axis and Y axis, meaning that theta = <NUM> is top of the antenna unit, theta = <NUM>° is bottom of the antenna unit and theta = -<NUM>° is behind the antenna (-Y)).

The back reflection of the glass panel <NUM> is significantly reduced for an antenna unit <NUM> according to the invention. This embodiment comprises an antenna unit <NUM> with a rectangular antenna, as shown in <FIG> and where metallic elements cover at least non-fixing portions. Same behaviour can be simulated in presence of at least one hole <NUM> on the metallic element <NUM> when the maximum dimensions of the hole are in direct link with the cut-off frequency of the aperture of the hole.

Since the glass panel <NUM> is provided with the antenna unit <NUM>, it is possible to reduce the possibility of occurrence of thermal cracks in the portion of the glass panel <NUM> located opposite the antenna unit <NUM> while minimizing the back reflection of the glass panel <NUM> in the portion of the glass panel located opposite the antenna unit <NUM>. Therefore, the glass panel <NUM> with an antenna can be suitably used as a glass panel for a window glass of existing or new buildings, houses and the like.

Further, in a glazing unit according to the invention, the antenna unit <NUM> can be provided on the second main surface on the indoor side of the glass panel <NUM>. Thereby, it is possible to prevent the antenna unit <NUM> from damaging the external appearance of the building, and it is possible to prevent the antenna unit <NUM> from being exposed to the outside air, so that the durability can be improved. Furthermore, in the glass panel <NUM> with an antenna, the antenna unit <NUM> is provided on the upper side of the glass panel <NUM> and on either one of the left and right sides. Therefore, by passing the wiring connected to the antenna of the antenna unit <NUM> from the glass panel to the ceiling back side, the wall, etc., it is possible to reduce the number of wires exposed to the glass panel <NUM> and the wall inside the building interior it can.

Claim 1:
Glazing unit (<NUM>) extending along a plane, P, defined by a longitudinal axis, X, and a vertical axis, Z; having a width, W, measured along the longitudinal axis, X, and a length, L, measured along the vertical axis, Z, comprising at least a glass panel (<NUM>) and an antenna unit (<NUM>) wherein
the antenna unit comprises :
a. an antenna (<NUM>)
b. a fixing portion (13A) for fixing the antenna to the glass panel so that a space through which air can flow is formed between the glass panel and the antenna
c. at least one non-fixing portion
d. at least one metallic element (<NUM>) placed over at least a part of the non-fixing portion of the antenna unit and the at least one metallic element further comprises at least a hole (<NUM>) corresponding with the space of the antenna unit such that air can flow through the at least a hole from the space to outside of the antenna unit.