Patent Description:
With progress of wireless communication technology, a wireless communication technology has been applied in an interactive white board, and the wireless data transmission function in the interactive white board needs the support of antennas.

In the interactive white board, wireless access point function and connection to a screen transmitter are realized through an antenna. A user of the wireless access point function and the screen transmitter are usually in front of the interactive white board. The users in front of the interactive white board can access a network through the wireless access point function of the interactive white board, and the data on PC can be transmitted to the interactive white board through the screen transmitter for display.

At present, the antenna in the interactive white board is omnidirectional radiation, and a forward radiation performance of the antenna is poor. In order to improve the forward radiation performance, a complex antenna is arranged, resulting in an increase in the volume of the entire antenna. <CIT> discloses a wireless module comprising a substrate, a ground pattern disposed on the substrate, a first antenna, a second antenna, and a conductive base plate, which is capable of improving isolation between two antennas and expanding a frequency band, in which isolation can be ensured. <CIT> discloses a dual-band antenna module comprising a first radiator, a second radiator, a first filter and a second filter, and providing a good isolation in the different bands. <CIT> discloses a miniature wideband attenna for <NUM> mobile networks, comprising a dielectric substrate, a coplanar waveguide feed structure on a front of the dielectric substrate, a main radiator, a second and third radiators and a first radiator on a back of the dielectric substrate, wherein high unit separation is a achieved without increase on the size of the antenna unit.

The purpose of embodiments of the present disclosure is to provide an antenna assembly and an interactive white board in order to solve problems of omnidirectional radiation, poor forward radiation performance and large volume of the antenna in the interactive white board.

In order to achieve this purpose, the embodiments of the present disclosure adopt the following technical scheme:.

A first aspect provides an antenna assembly according to claim <NUM>.

In a second aspect, the present disclosure provides an interactive white board. The interactive white board comprises a display screen, a frame arranged around the display screen, and an antenna assembly according to the first aspect, wherein the antenna assembly is located in the interactive white board and connected with the frame, and a surface, which is not provided with the metal resonant cavity, of the dielectric substrate in the antenna assembly faces the frame.

In the antenna assembly according to embodiments of the present disclosure, the first surface of the dielectric substrate is provided with the ground plane and the closed clearance region located in the ground plane, the first antenna unit and the second antenna unit are spaced apart on the first surface of the dielectric substrate and located in the clearance region. The radio frequency chip is arranged on the dielectric substrate, and connected with the first antenna unit and the second antenna unit respectively. The metal resonant cavity is arranged on the second surface of the dielectric substrate. In the direction perpendicular to the second surface, at least a part of the projection of the clearance region on the metal resonant cavity is within an outer contour of the metal resonant cavity. When the antenna assembly is installed on the interactive white board, the antenna assembly can be located in the interactive white board and connected with the frame, and the first surface, which is not provided with the metal resonant cavity, of the dielectric substrate in the antenna assembly faces the frame, so that the electromagnetic wave radiated from the antenna unit in the clearance region to the inside of the metal resonant cavity is reflected by the metal resonant cavity, and the reflected electromagnetic wave is radiated toward the direction of the first surface, thereby realizing that the antenna assembly radiates the electromagnetic wave to the side, which is provided with the first surface, of the dielectric substrate, and enhancing an intensity of the electromagnetic wave radiated from the side provided with the first surface. Moreover, the first antenna unit and the second antenna unit are arranged orthogonally, the isolation between the first antenna unit and the second antenna unit is high, and the first antenna unit and the second antenna unit does not interfere with each other, thereby improving the radiation performance of the entire antenna assembly. In addition, the antenna unit is arranged in a closed clearance region, and thus wiring of the antenna unit can be simplified to reduce an area of the dielectric substrate, so that the antenna assembly can be made smaller.

The present disclosure will be further described in detail according to the drawings and embodiments.

In the figures,
<NUM>. Dielectric substrate; <NUM>. Ground plane; <NUM>. Clearance region; <NUM>. First clearance region; <NUM>. First boundary; <NUM>. Second boundary; <NUM>. Second clearance region; <NUM>. Third boundary; <NUM>. Fourth boundary; <NUM>. Grounded stubs for increased isolation; <NUM>. First coplanar waveguide transmission line; <NUM>. Second coplanar waveguide transmission line; <NUM>. Third coplanar waveguide transmission line; <NUM>. Fourth coplanar waveguide transmission line; <NUM>. Antenna unit; <NUM>. First antenna unit; <NUM>. First feeder stub; <NUM>. First ground stub; <NUM>. First ground sub-stub; <NUM>. Second ground sub-stub; <NUM>. Third ground sub-stub; <NUM>. Fourth ground sub-stub; <NUM>. Third ground stub; <NUM>. Second antenna unit; <NUM>. Second feeder stub; <NUM>. Second ground stub; <NUM>. Fifth ground sub-stub; <NUM>. Sixth ground sub-stub; <NUM>. Seventh ground sub-stub; <NUM>. Eighth ground sub-stub; <NUM>. Fourth ground stub; <NUM>. Third antenna unit; <NUM>. Fourth antenna unit; <NUM>. Metal resonant cavity; <NUM>. Radio frequency chip; <NUM>. First radio frequency chip; <NUM>. Second radio frequency chip; <NUM>. Interactive white board; <NUM>. Display screen; <NUM>. Frame; <NUM>. Lower frame; <NUM>. Avoidance hole; <NUM>. Bottom surface; <NUM>. Side surface; <NUM>. Antenna assembly; <NUM>. Decorative piece.

In order to make the technical problems to be solved, the technical solutions to be adopted and the technical effects to be achieved by the present disclosure more clear, the technical solutions of embodiments of the present disclosure will be further described in detail hereinafter in combination with the accompanying drawings. Obviously, the described embodiments are only a part of embodiments of the present disclosure, not all of embodiments of the present disclosure.

In the description of the present disclosure, unless otherwise specified and limited, the terms "connected with/to", "connected" and "fixed" should be interpreted broadly. For example, they can be fixedly connected, detachably connected, or integrated. It can be a mechanical connection or an electrical connection. And they can be directly connected or indirectly connected through an intermediate medium, or, they can be the connection between two components or the interaction relationship between two components. For those skilled in the art, the concrete meaning of the above-mentioned terms in the present disclosure can be understood under concrete circumstances.

In the present disclosure, unless expressly stipulated and defined otherwise, a first feature being "above" or "below" a second feature may comprise that the first feature directly contacts with the second feature, or may comprise that the first feature does not directly contact with the second feature, rather than contact through another feature therebetween. Moreover, the first feature being "above", "over" and "on" the second feature may comprise that the first feature is directly above and obliquely above the second feature, or simply means that the level of the first feature is higher than that of the second feature. The first feature being "below", "under" and "underneath" the second feature comprises that the first feature is directly below and obliquely below the second feature, or simply means that the level of the first feature is smaller than that of the second feature.

As shown in <FIG>, an antenna assembly according to an embodiment of the present disclosure comprises a dielectric substrate <NUM>, an antenna unit <NUM>, a radio frequency chip <NUM> and a metal resonant cavity <NUM>.

Therein, the dielectric substrate <NUM> is a PCB board of the antenna assembly, the antenna unit <NUM> is a unit that radiates electromagnetic waves, and the antenna unit <NUM> is a metal sheet with a preset shape printed on the surface of the dielectric substrate <NUM>, for example, a copper sheet with various shapes printed on the surface of the dielectric substrate <NUM>. Therein, the antenna unit <NUM> includes a first antenna unit <NUM> and a second antenna unit <NUM>. The first antenna unit <NUM> and the second antenna unit <NUM> can be electrically connected with the radio frequency chip <NUM> via a transmission line, for example, the first antenna unit <NUM> and the second antenna unit <NUM> can be electrically connected with the radio frequency chip <NUM> through a transmission line printed on the dielectric substrate <NUM>.

The metal resonant cavity <NUM> is a cover made of metal materials such as stainless steel, galvanized steel plate, etc. The metal resonant cavity <NUM> is provided with an opening. Specifically, the metal resonant cavity <NUM> is a cover structure. The cover structure includes a bottom surface and a side surface connected with the bottom surface. The bottom surface and the side surfaces form a cover with an opening, preferably, a rectangular metal resonant cavity, which facilitates manufacturing the metal resonant cavity.

As shown in <FIG> and <FIG>, a surface B in <FIG> is a first surface of the dielectric substrate <NUM>. The first surface B is provided with a ground plane <NUM> and a closed clearance region <NUM> located in the ground plane <NUM>. Therein, the clearance region <NUM> is a region in the ground plane <NUM> where ground plane has been partially removed, and the clearance region <NUM> is a closed clearance region. The first antenna unit <NUM> and the second antenna unit <NUM> are spaced apart in the clearance region, which can improve a radiation efficiency of the antenna unit, and can be simplified to reduce an area of the antenna unit occupying the dielectric substrate <NUM>, so that the entire antenna assembly can be made smaller. In addition, the first antenna unit <NUM> and the second antenna unit <NUM> are orthogonal. The first antenna unit <NUM> and the second antenna unit <NUM> being orthogonal means that a phase difference between a phase of the electromagnetic wave radiated by the first antenna unit <NUM> and a phase of the electromagnetic wave radiated by the second antenna unit <NUM> is <NUM>°, so as to improve an isolation between the first antenna unit <NUM> and the second antenna unit <NUM> and improve the radiation performance of the antenna assembly.

A surface A in <FIG> is a second surface A of the dielectric substrate <NUM>, and the second surface A is provided with the metal resonant cavity <NUM>. In a direction perpendicular to the second surface A, at least a part of a projection of the clearance region <NUM> on the metal resonant cavity <NUM> is within an outer contour of the metal resonant cavity <NUM>. It should be noted that the first surface B and the second surface A of the dielectric substrate <NUM> are two surfaces of the dielectric substrate <NUM> used for arranging electrical components, that is, they are two surfaces on different sides of a main body of the dielectric substrate <NUM>.

As shown in <FIG>, in the embodiment of the present disclosure, the first antenna unit <NUM> and the second antenna unit <NUM> can radiate electromagnetic waves in all directions. The entire antenna assembly is finally required that a side (side F in <FIG>), which is provided with the first antenna unit <NUM> and the second antenna unit <NUM>, of the dielectric substrate <NUM> radiates electromagnetic waves (directions of multiple arrow on side F in <FIG> are radiation directions). As shown in <FIG>, the metal resonant cavity <NUM> is arranged on a surface of the dielectric substrate <NUM> facing away from the first antenna unit <NUM> and the second antenna unit <NUM>. Moreover, since at least a part of the projection of the clearance region <NUM> on the metal resonant cavity <NUM> is within the outer contour of the metal resonant cavity <NUM>, at least a part of the electromagnetic waves radiated by the first antenna unit <NUM> and the second antenna unit <NUM> arranged in the clearance region <NUM> toward the metal resonant cavity <NUM> are reflected by an inner wall of the metal resonant cavity <NUM>. The reflected electromagnetic wave is radiated to a side (side F in <FIG>), which is provided with the first antenna unit <NUM> and the second antenna unit <NUM>, of the dielectric substrate <NUM>. On the one hand, the entire antenna assembly radiates electromagnetic waves only at the side F, and a directivity of the electromagnetic waves radiated by the antenna assembly is good. On the other hand, the electromagnetic waves radiated by the first antenna unit <NUM> and the second antenna unit <NUM> toward the metal resonant cavity <NUM> are reflected and then superimposed on electromagnetic waves radiated toward the side F, thereby enhancing the intensity of the electromagnetic wave radiated toward the side F. On the other hand, the metal resonant cavity <NUM> can also prevent the external electromagnetic wave from causing electromagnetic interference to the antenna unit <NUM>, which improves an anti-electromagnetic interference performance of the antenna assembly.

In a preferred embodiment, the projection of the clearance region <NUM> on the metal resonant cavity <NUM> is within the outer contour of the metal resonant cavity <NUM>, so that all electromagnetic waves radiated by sides of the first antenna unit <NUM> and the second antenna unit <NUM> disposed in the clearance region <NUM> toward the metal resonant cavity <NUM> are reflected by an inner wall of the metal resonant cavity <NUM>, which enhances the intensity of electromagnetic waves radiated toward the side F.

<FIG> is a 3D schematic diagram of antenna radiation gain, wherein Fig. a in <FIG> is a 3D schematic diagram of radiation gain of the antenna after the metal resonant cavity <NUM> is added, and Fig. b in <FIG> is a 3D schematic diagram of radiation gain of the antenna before the metal resonant cavity <NUM> is added. It can be seen from Figs. a and b in <FIG> that in Fig. a, the radiation gain of the antenna after the metal resonant cavity <NUM> is added in <FIG> is concentrated in an upper region, the upper region is taken as a forward direction of the interactive white board, which can improve the forward radiation ability of the antenna assembly, and in Fig. b, the radiation gain of the antenna before the metal resonant cavity <NUM> is added is uniformly distributed in the upper and lower regions.

<FIG> is a 2D schematic diagram of antenna radiation gain. Therein, in <FIG>, Fig. a is a 2D schematic diagram of radiation gain of the antenna after the metal resonant cavity <NUM> is added, and Fig. b is a 2D schematic diagram of radiation gain of the antenna before the metal resonant cavity <NUM> is added. It can be seen from Figs. a and b in <FIG> that in Fig. a, the radiation gain of the antenna after the metal resonant cavity <NUM> is added reaches <NUM>. 1735dB, and in Fig. b, the radiation gain of the antenna before the metal resonant cavity <NUM> is added is <NUM>. That is, the radiation gain increases significantly after the metal resonant cavity <NUM> is added.

In the antenna assembly according to this embodiment of the present disclosure, the first surface of the dielectric substrate is provided with the ground plane and the closed clearance region located in the ground plane, the first antenna unit and the second antenna unit are spaced apart on the first surface of the dielectric substrate and located in the clearance region, the radio frequency chip is arranged on the dielectric substrate, and connected with the first antenna unit and the second antenna unit respectively, the metal resonant cavity is arranged on the second surface of the dielectric substrate, and in the direction perpendicular to the second surface, at least a part of the projection of the clearance region on the metal resonant cavity is within an outer contour of the metal resonant cavity. When the antenna assembly is installed on the interactive white board, the antenna assembly can be located in the interactive white board and connected with the frame. The first surface, which is not provided with the metal resonant cavity, of the dielectric substrate in the antenna assembly faces the frame, so that the electromagnetic wave radiated by the antenna unit to the inside of the metal resonant cavity is reflected by the metal resonant cavity, and the reflected electromagnetic wave is radiated toward the direction of the first surface, and thus realizing that the antenna assembly radiates the electromagnetic wave to the side, which is provided with the first surface, of the dielectric substrate, and enhancing an intensity of the electromagnetic wave radiated from the side which is provided with the first surface. Moreover, the first antenna unit and the second antenna unit are arranged orthogonally, and the isolation between the first antenna unit and the second antenna unit is high and the first antenna unit and the second antenna unit do not interfere with each other, thereby improving the radiation performance of the entire antenna assembly. In addition, the antenna unit is arranged in a closed clearance region, and thus wiring of the antenna unit can be simplified to reduce an area of the dielectric substrate, so that the antenna assembly can be made smaller.

In an optional embodiment of the present disclosure, the radio frequency chip <NUM> is arranged on a second surface A of the dielectric substrate <NUM>, and the first antenna unit <NUM> and the second antenna unit <NUM> is arranged on the first surface B of the dielectric substrate <NUM>. Since the radio frequency chip <NUM> and the antenna unit <NUM> are located on two different surfaces of the dielectric substrate <NUM>, the radio frequency chip <NUM> may connect with the first antenna unit <NUM> and the second antenna unit <NUM> through metal vias and transmission lines, so that the radio frequency chip <NUM>, the first antenna unit <NUM> and the second antenna unit <NUM> can be arranged by making full use of the space on both sides of the dielectric substrate <NUM>, thereby reducing the area of the dielectric substrate <NUM>. Therefore, the embodiment can be applied to the scene where the radio frequency chip <NUM>, the first antenna unit <NUM> and the second antenna unit <NUM> cannot be arranged on the same surface of the dielectric substrate <NUM> due to the limited overall space of the interactive white board. In addition, the radio frequency chip <NUM> and the metal resonant cavity <NUM> are both arranged on the second surface A. During production and manufacture, the radio frequency chip <NUM> and the metal resonant cavity <NUM> can be simultaneously arranged on the second surface A of the dielectric substrate <NUM> through the SMT process, which eliminates the need for additional processes and reduces the manufacturing cost.

Definitely, the radio frequency chip <NUM> may also be arranged on the first surface B of the dielectric substrate <NUM>, that is, the radio frequency chip <NUM>, the first antenna unit <NUM> and the second antenna unit <NUM> are arranged on the same surface of the dielectric substrate <NUM>, and pins of the radio frequency chip <NUM> can be directly connected with the transmission line without providing metal vias on the dielectric substrate <NUM>, thereby reducing manufacturing cost of the dielectric substrate <NUM>, and meanwhile being applied to the scene where the radio frequency chip <NUM>, the first antenna unit <NUM> and the second antenna unit <NUM> are arranged on the same surface of the dielectric substrate <NUM> due to the limited overall space of the interactive white board. In practical application, those skilled in the art can arrange the radio frequency chip <NUM>, the first antenna unit <NUM> and the second antenna unit <NUM> on the same surface or on different surfaces according to actual needs, and the embodiments of the present disclosure are not limited thereto.

In another embodiment of the present disclosure, the first antenna unit <NUM> and the second antenna unit <NUM> are electrically connected with the radio frequency chip <NUM> through a coplanar waveguide transmission line, and the coplanar waveguide transmission line may further be provided with an impedance matching circuit, for example, a π-shaped matching circuit. By arranging the impedance matching circuit, the frequency of the antenna assembly can be adjusted after a frequency offset of the antenna assembly, and the antenna assembly can be matched with an active device so as to improve the overall radiation performance of the antenna assembly.

In practical applications, the metal resonant cavity <NUM> is provided on the second surface A of the dielectric substrate <NUM> by welding, buckles, locking screws, etc. Optionally, a contact surface between the metal resonant cavity <NUM> and the dielectric substrate <NUM> may also be provided with conductive fabric so as to improve the electromagnetic shielding performance of the metal resonant cavity <NUM>.

In a preferred embodiment, a distance from the bottom of the metal resonant cavity <NUM> to the antenna unit <NUM> is equal to one fourth of a wavelength of the electromagnetic wave radiated by the antenna unit <NUM>. As shown in <FIG>, L=λ/<NUM>, wherein L is the distance from the bottom of the metal resonant cavity <NUM> to the antenna unit <NUM>, and λ is the wavelength of the electromagnetic wave. By setting the distance from the bottom of the metal resonant cavity <NUM> to the antenna unit <NUM> to be equal to one fourth of the wavelength of the electromagnetic wave radiated by the antenna unit <NUM>, when the electromagnetic wave radiated by the antenna unit <NUM> to the bottom of the metal resonant cavity <NUM> reaches the antenna unit <NUM> through reflection, the reflected electromagnetic wave and the electromagnetic wave radiated by the antenna unit <NUM> have a same phase. The superposition of the electromagnetic waves in the same phase can improve the signal intensity of the electromagnetic wave, and the forward radiation performance of the entire antenna assembly.

As shown in <FIG>, in an optional embodiment of the present disclosure, the radio frequency chip <NUM> includes a first radio frequency chip <NUM>, the clearance region <NUM> is provided with grounded stubs for increased isolation <NUM>, the grounded stubs for increased isolation <NUM> divide the clearance region <NUM> into a closed first clearance region <NUM> and a closed second clearance region <NUM>, the first antenna unit <NUM> is arranged in the first clearance region <NUM>, and the second antenna unit <NUM> is arranged in the second clearance region <NUM>. Specifically, the first antenna unit <NUM> and the second antenna unit <NUM> are located on the same side of the first radio frequency chip <NUM>, the first antenna unit <NUM> is located between the second antenna unit <NUM> and the first radio frequency chip <NUM>, the first antenna unit <NUM> is connected with the first radio frequency chip <NUM> through the first coplanar waveguide transmission line <NUM>, and the second antenna unit <NUM> is connected with the first radio frequency chip <NUM> through the second coplanar waveguide transmission line <NUM>.

When the antenna unit <NUM> according to the embodiment of the present disclosure includes the first antenna unit <NUM> and the second antenna unit <NUM>, the clearance region <NUM> is divided into a closed first clearance region <NUM> and a closed second clearance region <NUM> by the grounded stubs for increased isolation <NUM>, so that the first antenna unit <NUM> located in the first clearance region <NUM> and the second antenna unit <NUM> located in the second clearance region <NUM> are isolated, thereby improving the isolation between the first antenna unit <NUM> and the second antenna unit <NUM>. Thus, the interference between the first antenna unit <NUM> and the second antenna unit <NUM> is avoided, the anti-interference ability of the first antenna unit <NUM> and the second antenna unit <NUM> is improved, and the radiation performance of the antenna assembly is improved.

It should be noted that when the first radio frequency chip <NUM>, the first antenna unit <NUM> and the second antenna unit <NUM> are arranged on the same surface of the dielectric substrate <NUM>, the first radio frequency chip <NUM> can be directly connected with the first antenna unit <NUM> and the second antenna unit <NUM> through the coplanar waveguide transmission lines (<NUM>, <NUM>). When the first radio frequency chip <NUM>, the first antenna unit <NUM> and the second antenna unit <NUM> are arranged on different surfaces of the dielectric substrate <NUM>, after the coplanar waveguide transmission lines (<NUM>, <NUM>) are connected with the first antenna unit <NUM> and the second antenna unit <NUM>, the coplanar waveguide transmission lines (<NUM>, <NUM>) are connected to the first radio frequency chip <NUM> on the other side through metal vias. Therein, the layout of the coplanar waveguide transmission lines (<NUM>, <NUM>) on the dielectric substrate <NUM> can be determined according to the actual situation, and the embodiments of the present disclosure do not limit the wiring of the coplanar waveguide transmission lines (<NUM>, <NUM>).

In an optional embodiment, when the grounded stubs for increased isolation <NUM> divide the clearance region <NUM> into a closed first clearance region <NUM> and a closed second clearance region <NUM>, the first antenna unit <NUM> is arranged in the first clearance region <NUM>, and the second antenna unit <NUM> is arranged in the second clearance region <NUM>, the projection of the first clearance region <NUM> or the second clearance region <NUM> on the metal resonant cavity <NUM> is within the outer contour of the metal resonant cavity <NUM>, so that the electromagnetic wave radiated from the first antenna unit <NUM> or the second antenna unit <NUM> toward the metal resonant cavity <NUM> is reflected by the inner wall of the metal resonant cavity <NUM>, thereby enhancing the intensity of the electromagnetic wave radiated toward the side F.

In order to enable those skilled in the art to understand the antenna assembly of the embodiment of the present disclosure more clearly, the antenna assembly of the embodiment of the present disclosure will be described hereinafter with reference to <FIG>.

As shown in <FIG>, the first clearance region <NUM> in the ground plane <NUM> is a square clearance region, the first antenna unit <NUM> includes a first feeder stub <NUM> and a first ground stub <NUM>, the first feeder stub <NUM> extends from a first boundary <NUM> of the first clearance region <NUM> to the inside of the first clearance region <NUM>, and an end of the first feeder stub <NUM> close to the first boundary <NUM> is connected with the first radio frequency chip <NUM> through the first coplanar waveguide transmission line <NUM>. The first ground stub <NUM> extends from a second boundary <NUM> of the first clearance region <NUM> to the inside of the first clearance region <NUM>. The first boundary <NUM> and the second boundary <NUM> are two adjacent boundaries of the first clearance region <NUM>. The first feeder stub <NUM> and the first ground stub <NUM> are arranged orthogonally and have no public endpoint. The first feeder stub <NUM> is perpendicular to the first boundary <NUM>. Therein, the orthogonal arrangement may mean that the first feeder stub <NUM> is perpendicular to the first ground stub <NUM>.

The second clearance region <NUM> is a square clearance region, and the second antenna unit <NUM> includes a second feeder stub <NUM> and a second ground stub <NUM>. The second feeder stub <NUM> extends from a third boundary <NUM> of the second clearance region <NUM> to the inside of the second clearance region <NUM>. One end of the second feeder stub <NUM> close to the third boundary <NUM> is connected with the first radio frequency chip <NUM> through the second coplanar waveguide transmission line <NUM>. The second ground stub <NUM> extends from a fourth boundary <NUM> of the second clearance region <NUM> to the inside of the second clearance region <NUM>. The third boundary <NUM> and the fourth boundary <NUM> are two adjacent boundaries of the second clearance region <NUM>. The second feeder stub <NUM> and the second ground stub <NUM> are arranged orthogonally and have no public endpoint. The second feeder stub <NUM> is perpendicular to the third boundary <NUM>.

It should be noted that the first boundary <NUM> and the third boundary <NUM> are orthogonal or parallel. The first boundary <NUM> and the third boundary <NUM> are orthogonal, so that the radiation directions of the first antenna unit <NUM> and the second antenna unit <NUM> are orthogonal, the first antenna unit <NUM> and the second antenna unit <NUM> do not interfere with each other, and the degree of isolation is high.

Of the two antenna units shown in <FIG>, the first antenna unit <NUM> and the second antenna unit <NUM> respectively composes a feeder stub for feeder and a ground stub for ground, and the two stubs are placed orthogonally. The feeder stub is in the form of a monopole antenna. According to the antenna radiation principle, when a length of the feeder stub is about one fourth of the wavelength of the radiation frequency, the electric field intensity at the top of the feeder stub is the strongest. In the embodiment of the present disclosure, after the ground stub is introduced at an orthogonal side of the feeder stub, the ground stub can be coupled with the feeder stub to change the radiation frequency, so that by adjusting the position and length of the ground stub, a current path length of the feeder stub can be effectively shortened by using the coupling effect, thereby reducing the size of the feeder stub. The size of the feeder stub shown in <FIG> is about one eighth of the wavelength of the radiation frequency, the size of the antenna unit is greatly reduced, so that the required clearance area of the antenna unit can be smaller, and the size of the antenna assembly can be made smaller. Moreover, the antenna unit includes two stubs, and the structure is simple.

<FIG> is a schematic diagram of the return loss of the antenna assembly in <FIG>. It can be seen from <FIG> that the return loss of the two antenna elements in <FIG> meets <NUM>-<NUM> at an impedance bandwidth with less than -<NUM> dB.

It should be noted that although the structures of the first antenna unit <NUM> and the second antenna unit <NUM> have been exemplified with reference to <FIG>, in practical applications, those skilled in the art can also arrange the first antenna unit <NUM> and the second antenna unit <NUM> with any structure. Hereinafter, the other two antenna units of the present disclosure will be described with reference to <FIG> and <FIG>.

As shown in <FIG>, in an optional embodiment, the first clearance region <NUM> is a square clearance region, and the first antenna unit <NUM> includes a first feeder stub <NUM>, a first ground stub <NUM>, and a third ground stub <NUM> arranged in parallel. The first feeder stub <NUM>, the first ground stub <NUM>, and the third ground stub <NUM> all extend from the first boundary <NUM> of the first clearance region <NUM> to the inside of the first clearance region <NUM>. One end of the first feeder stub <NUM> close to the first boundary <NUM> is connected with the first clearance region chip <NUM> through the first coplanar waveguide transmission line <NUM>. The first ground stub <NUM> and the third ground stub <NUM> are located on both sides of the first feeder stub <NUM>, and the first feeder stub <NUM> is perpendicular to the first boundary <NUM>.

As shown in <FIG>, the second clearance region <NUM> is a square clearance region, and the second antenna unit <NUM> includes a second feeder stub <NUM>, a second ground stub <NUM> and a fourth ground stub <NUM> arranged in parallel. The second feeder stub <NUM>, the second ground stub <NUM> and the fourth ground stub <NUM> all extend from the third boundary <NUM> of the second clearance region <NUM> to the inside of the second headroom area <NUM>. One end of the second feeder stub <NUM> close to the third boundary <NUM> is connected with the first radio frequency chip <NUM> through the second coplanar waveguide transmission line <NUM>. The second ground stub <NUM> and the fourth ground stub <NUM> are located on both sides of the second feeder stub <NUM>. The second feeder stub <NUM> is perpendicular to the third boundary <NUM>. It should be noted that the first boundary <NUM> and the third boundary <NUM> are orthogonal or parallel.

As shown in <FIG>, the first clearance region <NUM> is a square clearance region, and the first antenna unit <NUM> includes a first feeder stub <NUM> and a first ground stub <NUM>. The first feeder stub <NUM> extends from the first boundary <NUM> of the first clearance region <NUM> to the inside of the first clearance region <NUM>. One end of the first feeder stub <NUM> close to the first boundary <NUM> is connected with the first radio frequency chip <NUM> through the first coplanar waveguide transmission line <NUM>.

The first ground stub <NUM> includes a first ground sub-stub <NUM>, a second ground sub-stub <NUM>, a third ground sub-stub <NUM>, and a fourth ground sub-stub <NUM>. The first ground sub-stub <NUM> is parallel to the first feeder stub <NUM> and extends from the first boundary <NUM> of the first clearance region <NUM> to the inside of the first clearance region <NUM>. The second ground sub-stub <NUM>, the third ground sub-stub <NUM>, and the fourth ground sub-stub <NUM> are connected end-to-end in sequence, and two adjacent ground sub-stubs are perpendicular to each other. One end, which is not connected with the third ground sub-stub <NUM>, of the second ground sub-stub <NUM> is connected to one end, which is away from the first boundary <NUM>, of the first ground sub-stub <NUM>, and the second ground sub-stub <NUM> is perpendicular to the first ground sub-stub <NUM>. One end, which is not connected with the third ground sub-stub <NUM>, of the fourth ground sub-stub <NUM> is connected with the first feeder stub <NUM>, and the first ground sub-stub <NUM> and the third ground sub-stub <NUM> are respectively located on both sides of the first feeder stub <NUM>.

As shown in <FIG>, the second clearance region <NUM> is a square clearance region, and the second antenna unit <NUM> includes a second feeder stub <NUM> and a second ground stub <NUM>. The second feeder stub <NUM> extends from the third boundary <NUM> of the second clearance region <NUM> to the inside of the second clearance region <NUM>. One end of the second feeder stub <NUM> close to the third boundary <NUM> is connected with the first radio frequency chip <NUM> through the second coplanar waveguide transmission line <NUM>.

The second ground stub <NUM> includes a fifth ground sub-stub <NUM>, a sixth ground sub-stub <NUM>, a seventh ground sub-stub <NUM>, and an eighth ground sub-stub <NUM>. The fifth ground sub-stub <NUM> is parallel to the second feeder stub <NUM> and extends from the third boundary <NUM> of the second clearance region <NUM> to the inside of the second clearance region <NUM>. The sixth ground sub-stub <NUM>, the seventh ground sub-stub <NUM>, and the eighth ground sub-stub <NUM> are connected end-to-end in sequence, and two adjacent ground sub-stubs are perpendicular to each other. One end, which is not connected with the seventh ground sub-stub <NUM>, of the sixth ground sub-stub <NUM> is connected to one end, which is away from the third boundary <NUM>, of the fifth ground sub-stub <NUM>, and the sixth ground sub-stub <NUM> is perpendicular to the fifth ground sub-stub <NUM>. One end, which is not connected with the seventh ground sub-stub <NUM>, of the eighth ground sub-stub <NUM> is connected with the second feeder stub <NUM>. The fifth ground sub-stub <NUM> and the seventh ground sub-stub <NUM> are respectively located on both sides of the second feeder stub <NUM>. It should be noted that the first boundary <NUM> and the third boundary <NUM> are orthogonal or parallel.

Although the structure of the antenna unit <NUM>, the structure and wiring of the transmission line have been described above by taking the example that the antenna unit <NUM> includes two antenna units and the transmission line is a coplanar waveguide transmission line, in practical applications, those skilled in the art can arrange the number of antenna units <NUM>, design antenna units with different structures and transmission lines with different layouts according to actual needs, and the embodiments of the present disclosure do not limit the number and structure of antenna units, the structure and wiring mode of the transmission line are not limited.

<FIG> is a schematic diagram of another antenna assembly in the example of the present disclosure. In addition to the first antenna unit <NUM>, the second antenna unit <NUM> and the first radio frequency chip <NUM> shown in <FIG>, <FIG> or <FIG>, the antenna assembly in the embodiment of the present disclosure further includes a third antenna unit <NUM> and a fourth antenna unit <NUM>, the radio frequency chip <NUM> further includes a second radio frequency chip <NUM>, and the coplanar waveguide transmission line further includes a third coplanar waveguide transmission line <NUM> and a fourth coplanar waveguide transmission line <NUM>. Therein, the second radio frequency chip <NUM> is located on a side of the first radio frequency chip <NUM> away from the first antenna unit <NUM>, the third antenna unit <NUM> and the fourth antenna unit <NUM> are located on a side of the second radio frequency chip <NUM> away from the first radio frequency chip <NUM>, the third antenna unit <NUM> is located between the second radio frequency chip <NUM> and the fourth antenna unit <NUM>, the third antenna unit <NUM> and the first antenna unit <NUM> are mirror images of each other, the fourth antenna unit <NUM> and the second antenna unit <NUM> are mirror images of each other, the third antenna unit <NUM> is connected with the second radio frequency chip <NUM> through the third coplanar waveguide transmission line <NUM>, and the fourth antenna unit <NUM> is connected with the second radio frequency chip <NUM> through the fourth coplanar waveguide transmission line <NUM>. Therein, being the mirror image of each other may mean that the third antenna unit <NUM> and the first antenna unit <NUM> are mirror images of each other in structure, the fourth antenna unit <NUM> and the second antenna unit <NUM> are mirror images of each other in structure. Definitely, the structures of the third antenna unit <NUM> and the fourth antenna unit <NUM> may also be other structures, and the embodiments of the present disclosure are not limited thereto.

The antenna assembly according to the embodiment of the present disclosure includes a first antenna unit <NUM>, a second antenna unit <NUM>, a third antenna unit <NUM>, a fourth antenna unit <NUM>, a first radio frequency chip <NUM>, and a second radio frequency chip <NUM>. The second radio frequency chip <NUM> is located on a side of the first radio frequency chip <NUM> away from the first antenna unit <NUM>, the third antenna unit <NUM> and the fourth antenna unit <NUM> are located on a side of the second radio frequency chip <NUM> away from the first radio frequency chip <NUM>, and the third antenna unit <NUM> is located between the second radio frequency chip <NUM> and the fourth antenna unit <NUM>. On the one hand, the antenna assembly includes a first group of antennas units (the first antenna unit <NUM> and the second antenna unit <NUM>) and a second group of antenna units (the third antenna unit <NUM> and the fourth antenna unit <NUM>), and can realize different communication functions through the two groups of antennas. For example, the antenna assembly can realize the WiFi communication functions through the first group of antennas units, and realize the wireless AP (Access Point) function through the second group of antenna units. On the other hand, there are two radio frequency chips (first radio frequency chip <NUM> and second radio frequency chip <NUM>) between the first group of antennas units (the first antenna unit <NUM> and the second antenna unit <NUM>) and the second group of antenna units (the third antenna unit <NUM> and the fourth antenna unit <NUM>). The distance between the two groups of antennas is large, the isolation of the two groups of antennas is high, and the area of the entire antenna assembly is small.

<FIG> is a schematic diagram of another antenna assembly according to an embodiment of the present disclosure. In addition to the first antenna unit <NUM>, the second antenna unit <NUM> and the first radio frequency chip <NUM> shown in <FIG>, <FIG> or <FIG>, the antenna assembly of this embodiment in the present disclosure further includes the third antenna unit <NUM> and the fourth antenna unit <NUM>, the radio frequency chip <NUM> further includes the second radio frequency chip <NUM>, and the coplanar waveguide transmission line further includes the third coplanar waveguide transmission line <NUM> and the fourth coplanar waveguide transmission line <NUM>. Therein, the second radio frequency chip <NUM> is located on a side of the first radio frequency chip <NUM> away from the first antenna unit <NUM>, the third antenna unit <NUM> and the fourth antenna unit <NUM> are located between the second radio frequency chip <NUM> and the first radio frequency chip <NUM>, the third antenna unit <NUM> has the same structure as the first antenna unit <NUM>, the fourth antenna unit <NUM> has the same structure as the second antenna unit <NUM>, the third antenna unit <NUM> is located between the second radio frequency chip <NUM> and the fourth antenna unit <NUM>, the third antenna unit <NUM> is connected with the second radio frequency chip <NUM> through the third coplanar waveguide transmission line <NUM>, and the fourth antenna unit <NUM> is connected with the second radio frequency chip <NUM> through the fourth coplanar waveguide transmission line <NUM>. Definitely, the structures of the third antenna unit <NUM> and the fourth antenna unit <NUM> may also be other structures, and the embodiments of the present disclosure are not limited thereto.

The antenna assembly according to the embodiment of the present disclosure includes a first antenna unit <NUM>, a second antenna unit <NUM>, a third antenna unit <NUM>, a fourth antenna unit <NUM>, a first radio frequency chip <NUM> and a second radio frequency chip <NUM>. The second radio frequency chip <NUM> is located on a side of the first radio frequency chip <NUM> away from the first antenna unit <NUM>. The third antenna unit <NUM> and the fourth antenna unit <NUM> are located between the second radio frequency chip <NUM> and the first radio frequency chip <NUM>. On the one hand, the antenna assembly includes a first group of antennas units (the first antenna unit <NUM> and the second antenna unit <NUM>) and a second group of antenna units (the third antenna unit <NUM> and the fourth antenna unit <NUM>), and can realize different communication functions through the two groups of antennas. For example, the antenna assembly can realize the WiFi communication function through the first group of antennas units, and realize the wireless AP (Access Point) function through the second group of antenna units. On the other hand, the isolation of the two groups of antennas can be improved by increasing the distance between the first group of antennas units (the first antenna unit <NUM> and the second antenna unit <NUM>) and the second group of antenna units (the third antenna unit <NUM> and the fourth antenna unit <NUM>). The increase of the area of the dielectric substrate is suitable for scenes where the installation space of the antenna components is not limited.

As shown in <FIG>, the embodiment of the present disclosure provides an interactive white board <NUM>, and the interactive white board <NUM> includes a display screen <NUM>, a frame <NUM> arranged around the display screen <NUM>, and at least one antenna assembly <NUM> provided in the embodiment of the present disclosure. The antenna assembly <NUM> is located in the interactive white board <NUM> and connected to the frame <NUM>, wherein a surface, which is not provided with a metal resonant cavity, of the dielectric substrate in the antenna assembly <NUM> faces the frame <NUM>. That is, the antenna assembly <NUM> radiates electromagnetic waves to the outside of the interactive white board <NUM>.

Specifically, the display screen <NUM> is one of display screen selected from the group consisting of LCD, LED, OLED, etc. The frame <NUM> is a frame surrounding the display screen <NUM>. The frame <NUM> has a certain thickness in the direction perpendicular to the display screen <NUM>, so that the antenna assembly <NUM> is mounted on the frame <NUM>. In an optional embodiment, the number of antenna assemblies <NUM> is one or more.

In the interactive white board according to the embodiment of the present disclosure, the first surface of the dielectric substrate is provided with a ground plane and a closed clearance area located in the ground plane, the antenna unit is arranged on the first surface of the dielectric substrate and is located in the clearance area, the radio frequency chip is provided on the dielectric substrate and connected with the antenna unit, the metal resonant cavity is provided on the second surface of the dielectric substrate, and the projection of the metal resonant cavity on the first surface covers the antenna unit. When the antenna assembly is installed on the interactive white board, the antenna assembly can be located in the interactive white board and connected with the frame. The first surface, which is not provided with the metal resonant cavity, of the dielectric substrate in the antenna assembly faces the frame, so that the electromagnetic wave radiated by the antenna unit to the inside of the metal resonant cavity is reflected by the metal resonant cavity, and the reflected electromagnetic wave is radiated toward the first surface. Therefore, the antenna assembly radiates electromagnetic waves to the side of the dielectric substrate which is provided with the first surface, and the intensity of electromagnetic waves radiated from the surface of the dielectric substrate which is provided with the first surface is enhanced. In addition, the antenna unit is arranged in a closed clearance area, and wiring of the antenna unit can be simplified so as to reduce the area of the dielectric substrate, and thus the antenna assembly can be made smaller and the frame of the interactive white board can be made narrower.

Furthermore, the number of antenna units in the antenna assembly is one or more, the antenna unit and the radio frequency chip is arranged on the same or different surfaces of the dielectric substrate, and the interactive white board may select the antenna assembly according to the installation space, radiation performance and radiation direction of the antenna assembly.

As shown in <FIG>, in an optional embodiment, the frame <NUM> of the interactive white board <NUM> includes a lower frame <NUM>, and the antenna assembly <NUM> is detachably connected with the lower frame <NUM>. One surface, which is provided with the metal resonant cavity <NUM>, of the dielectric substrate <NUM> in the antenna assembly <NUM> faces a bottom surface <NUM> of the lower frame <NUM>, and the bottom surface <NUM> is substantially perpendicular to the display screen <NUM>. For example, as shown in <FIG>, when the interactive white board <NUM> is placed on a horizontal plane, the bottom surface <NUM> of the lower frame <NUM> is a surface substantially parallel to the horizontal plane. Specifically, the material of the lower frame <NUM> is metal, and the bottom surface <NUM> of the lower frame <NUM> is provided with an avoidance hole <NUM> directly facing the antenna assembly <NUM>, so that after the antenna assembly <NUM> is mounted on the lower frame <NUM>, the surface, which is not provided with the metal resonant cavity <NUM>, of the dielectric substrate <NUM> in the antenna assembly <NUM> directly faces the avoidance hole <NUM>, and the antenna unit on the antenna assembly <NUM> can radiate electromagnetic waves to the outside of the interactive white board <NUM> through the avoidance hole <NUM>. The surface, which is not provided with the metal resonant cavity <NUM>, of the dielectric substrate <NUM> in the antenna assembly <NUM> is arranged toward the bottom surface <NUM> of the lower frame <NUM>. A surface of the lower frame <NUM> facing the user does not need to be provided with an avoidance hole, so that the interactive white board has a good appearance.

As shown in <FIG>, in another example, the surface, which is not provided with the metal resonant cavity <NUM>, of the dielectric substrate <NUM> in the antenna assembly <NUM> faces a side surface <NUM> of the lower frame <NUM>, wherein the side surface <NUM> is parallel to the display screen <NUM>. Specifically, when the interactive white board <NUM> is placed on a horizontal plane, the side surface <NUM> of the lower frame <NUM> is a plane substantially perpendicular to the horizontal plane, for example, the side surface <NUM> of the lower frame <NUM> is a surface facing the forward direction of the interactive white board, so that the antenna assembly <NUM> radiates electromagnetic waves directly toward the forward direction of the interactive white board.

Definitely, the antenna assembly <NUM> may also be mounted on other frames of the interactive white board <NUM>. For example, the antenna assembly <NUM> can be mounted on the left frame or the right frame. The surface, which is not provided with the metal resonant cavity <NUM>, of the dielectric substrate <NUM> in the antenna assembly <NUM> can also be in the same direction as the front of the display screen <NUM>. The embodiment of the present disclosure does not limit the mounting position and orientation of the antenna assembly <NUM>.

The antenna assembly according to the embodiment of the present disclosure is located at the lower frame of the interactive white board. The surface, which is not provided with a metal resonant, of the dielectric substrate <NUM> in the antenna assembly faces the bottom surface of the lower frame. On the one hand, the lower frame has sufficient installation space, which can facilitate the installation of the antenna assembly. On the other hand, the lower frame of the interactive white board is closer to the user, and the antenna assembly being located at the lower frame improves a wide radiation area, which improves the wireless network performance of the interactive white board.

Preferably, the interactive white board <NUM> further includes a decorative piece <NUM>, which covers the avoidance hole <NUM> so as to prevent the avoidance hole <NUM> from directly exposing the dielectric substrate <NUM> of the antenna assembly <NUM>, so that the interactive white board <NUM> has a good appearance.

In the explanation of this description, the description with reference to the terms "embodiment", "example", etc. means that the concrete feature, structure, material or characteristic described in conjunction with the embodiment or example is contained in at least one embodiment or example of the present disclosure. In this description, the schematic representation of the above-mentioned terms does not necessarily refer to the same embodiment or example.

Claim 1:
An antenna assembly (<NUM>), comprising:
a dielectric substrate (<NUM>), of which a first surface is provided with a ground plane (<NUM>) and a closed clearance region (<NUM>) located in the ground plane (<NUM>);
a first antenna unit (<NUM>) and a second antenna unit (<NUM>), the first antenna unit (<NUM>) and the second antenna unit (<NUM>) being spaced apart on the first surface of the dielectric substrate (<NUM>) and located in the clearance region (<NUM>), and the first antenna unit (<NUM>) and the second antenna unit (<NUM>) being orthogonally arranged;
a radio frequency chip (<NUM>), arranged on the dielectric substrate (<NUM>) and connected with the first antenna unit (<NUM>) and the second antenna unit (<NUM>) respectively;
characterized in that
a metal resonant cavity (<NUM>), arranged on a second surface of the dielectric substrate (<NUM>), wherein in a direction perpendicular to the second surface, at least a part of a projection of the clearance region (<NUM>) on the metal resonant cavity (<NUM>) is within an outer contour of the metal resonant cavity (<NUM>).