TWM493164U - Antenna structure with reduced metal shielding effect - Google Patents

Description

Antenna structure capable of reducing metal shadowing effect

An antenna structure capable of reducing metal shadowing effect can reduce the shadowing effect of the metal shielding on the loop antenna, and achieve the purpose of improving the radiation efficiency of the antenna.

With the advancement of wireless communication technology, wireless communication products have been widely used in daily life, and antenna components are one of the most important parts of wireless communication products. Antenna components usually occupy a large space for wireless communication products. How to reduce the size of antenna products to reduce the size of electronic devices is a very important issue.

In order to reduce the size and weight of the portable electronic device, the built-in multi-frequency antenna is generally designed to be a Planar Inverted F Antenna (PIFA) or a monopole antenna, and the PIFA antenna can be designed. Or the monopole antenna is disposed on the circuit board of the portable electronic device, thereby reducing the set volume of the antenna in the portable electronic device.

However, in practical applications, in order to meet the size requirement of 1/4 λ, the PIFA antenna cannot further reduce the footprint of the antenna on the circuit board, and the PIFA antenna cannot be designed on the circuit board. In this case, the loop antenna is a A fairly superior solution. Because the loop antenna only needs to use a relatively small board area, it can provide superior antenna radiation efficiency. However, when there are metal objects around the loop antenna, the metal object will have a shadowing effect on the antenna's ability to radiate radio signals, which significantly affects the radiation efficiency of the loop antenna. For example: mobile phone In order to meet the aesthetic needs of the shape or appearance, a metal casing or a metal ring is often used, which causes the radiation efficiency of the loop antenna to be greatly reduced by the influence of the metal casing, which is a big problem for the antenna designer.

The present invention mainly provides an antenna structure capable of reducing metal shadowing effect, which can reduce the shadowing effect of the metal shielding object located near the loop antenna on the loop antenna, and achieve the purpose of improving the radiation efficiency of the antenna.

The invention is an antenna structure capable of reducing metal shadowing effect, wherein the loop antenna is disposed in the clearance area of the circuit board, and the clearance area is an area on the circuit board where no grounding electric layer or other electronic components of the device are disposed. The loop antenna is electrically connected to the RF line of the electronic device by using the signal feed line, and is electrically connected to the ground layer and the connection unit through the ground line, and the connection unit is electrically connected to the adjacent metal shield, and the antenna structure can generate at least one resonance. frequency. Through the above antenna structure, the shielding effect of the metal shielding on the loop antenna can be reduced, and the radiation efficiency of the antenna can be improved.

The present invention is an antenna structure capable of reducing metal shadowing effect, wherein the antenna structure is disposed in an electronic device having a metal casing, and the loop antenna is disposed in a clearance area of the circuit board, and electrically connected to the RF of the electronic device through the signal feeding line. line. In addition, the loop antenna is electrically connected to the grounding layer and the connecting unit through a grounding wire, wherein the connecting unit is electrically connected to the metal casing of the electronic device, and the antenna structure can generate at least one resonant frequency. Through the above antenna structure, the shielding effect of the metal casing of the electronic device on the antenna structure can be reduced, thereby achieving the purpose of improving the radiation efficiency of the antenna.

In order to achieve the above object, the present invention provides a metal shadowing effect The antenna device is configured to transmit or receive an RF signal, comprising: at least one loop antenna, comprising: at least one substrate; a plurality of conductive layers disposed on a surface or an interior of the substrate, wherein a capacitance effect is formed between the plurality of conductive layers And generating a resonant frequency of the loop antenna; a circuit board carrying the loop antenna, and comprising: a ground layer; a clearing area for accommodating the loop antenna; and a plurality of grounding lines respectively connected to the respective conductive layers of the loop antenna; a signal feed line connecting at least one conductive layer of the loop antenna; at least one metal shield adjacent to the loop antenna, wherein a first spacing exists between the metal shield and the loop antenna; and a plurality of connecting units electrically connecting the metal shield Object, ground plane and grounding wire.

The present invention provides another antenna device capable of reducing metal shadowing effect, Transmitting or receiving an RF signal, comprising: at least one loop antenna comprising: at least one substrate; at least one first conductive layer disposed on a surface or an interior of the substrate; at least one second conductive layer disposed on a surface of the substrate or Internally, wherein the first conductive layer and the second conductive layer are used to generate a capacitive effect and form a resonant frequency of the loop antenna; a circuit board carrying the loop antenna and including: a ground layer; a clearance area for receiving a loop antenna; a plurality of ground lines respectively connected to the first conductive layer and the second conductive layer of the loop antenna; at least one signal feed line connected to the first conductive layer of the loop antenna; at least one metal shield adjacent to the loop antenna, wherein There is a first spacing between the metal shield and the loop antenna; and a plurality of connecting units electrically connecting the metal shield, the ground layer and the ground line.

The present invention also provides another antenna device capable of reducing metal shadowing effect. Transmitting or receiving radio frequency signals of a plurality of frequency bands, including: at least one loop antenna, comprising: at least one substrate; at least one first conductive layer disposed on a surface or an inner portion of the substrate; at least one second guide An electric layer disposed on a surface or an inner portion of the substrate; at least one third conductive layer disposed on a surface or an inner portion of the substrate, wherein the third conductive layer is disposed at a plane different from a plane formed by the first conductive layer or the second conductive layer, And a portion of the third conductive layer overlaps with a portion of the first conductive layer and a portion of the second conductive layer, wherein a capacitive effect is formed between the first conductive layer and the third conductive layer, and a first resonant frequency of the loop antenna is generated, and the second Forming a capacitance effect between the conductive layer and the third conductive layer, and generating a second resonant frequency of the loop antenna; a circuit board carrying the loop antenna, and comprising: a ground layer; a clearing area for accommodating the loop antenna; a grounding wire, respectively connected to the first conductive layer, the second conductive layer and the third conductive layer of the loop antenna; a signal feeding line connecting the third conductive layer of the loop antenna; at least one metal shielding, adjacent to the loop antenna, wherein the metal There is a first spacing between the shielding and the loop antenna; and a plurality of connecting units electrically connecting the metal shielding, the grounding layer and the grounding wire.

The present invention also provides another antenna device capable of reducing metal shadowing effect. Transmitting or receiving a plurality of frequency band RF signals, comprising: at least one loop antenna comprising: at least one substrate; at least one first conductive layer disposed on a surface or an inner portion of the substrate; and at least one second conductive layer disposed on a surface or an inner surface of the substrate; at least one third conductive layer disposed on a surface or an inner portion of the substrate; the third conductive layer is disposed at a plane different from a plane of the first conductive layer or the second conductive layer, and a portion of the third conductive layer The layers overlap with a portion of the first conductive layer and a portion of the second conductive layer, respectively, wherein a capacitive effect is formed between the first conductive layer and the third conductive layer, and a first resonant frequency of the loop antenna is generated, and the second conductive layer and the third conductive layer A capacitive effect is formed between the conductive layers, and a second resonant frequency of the loop antenna is generated; a circuit board carrying the loop antenna includes: a ground layer; a clearing area for accommodating the loop antenna; and a plurality of grounding lines, respectively Connecting the first conductive layer, the second conductive layer and the third conductive layer of the loop antenna; a first signal feed line connecting the first lead of the loop antenna An electrical layer; a second signal feed line connecting the second conductive layer of the loop antenna; at least one metal shield adjacent to the loop antenna, wherein a first spacing exists between the metal shield and the loop antenna; and a plurality of connecting units, Electrically connect the metal shield, ground plane and grounding wire.

In an embodiment of the novel antenna device, the length of the first pitch is greater than 0.3 mm.

In an embodiment of the novel antenna device, there is a second spacing between adjacent connecting units, and the length of the second spacing is greater than or equal to 1/8 of the maximum wavelength of the resonant frequency of the loop antenna.

In an embodiment of the present invention, the first conductive layer and the second conductive layer are respectively disposed on different planes, and a portion of the first conductive layer overlaps with a portion of the second conductive layer to generate a capacitive effect and form a resonance of the loop antenna. frequency.

In an embodiment of the present invention, the first conductive layer and the second conductive layer are disposed on the same or similar planes, and a gap exists between the first conductive layer and the second conductive layer, and the first conductive layer and the first conductive layer The two conductive layers are used to create a capacitive effect and form the resonant frequency of the loop antenna.

In an embodiment of the antenna device of the present invention, a second pitch and a third pitch exist between adjacent connecting units, and the length of the second pitch is greater than or equal to 1/8 of the maximum wavelength of the first resonant frequency of the loop antenna. And the length of the third pitch is greater than or equal to 1/8 of the maximum wavelength of the second resonant frequency of the loop antenna.

In an embodiment of the antenna device of the present invention, at least one grounding wire of the circuit board is directly connected to the metal shield through the connecting unit.

According to the antenna structure constructed by the novel, the metal shielding can be significantly reduced The effect of the radiation efficiency of the antenna is to maximize the effectiveness of the loop antenna. The features, implementations, and effects of the present invention are described in detail below with reference to the drawings.

10‧‧‧Antenna device

11‧‧‧loop antenna

111‧‧‧Substrate

112‧‧‧Overlapping area

1131‧‧‧First conductive layer

1133‧‧‧Second conductive layer

114‧‧‧ gap

13‧‧‧Circuit board

131‧‧‧ clearance area

133‧‧‧ Grounding layer

135‧‧‧ Grounding wire

137‧‧‧ signal feed line

15‧‧‧Metal shelter

17‧‧‧ Connection unit

20‧‧‧Antenna device

21‧‧‧ loop antenna

211‧‧‧Substrate

212‧‧‧Overlapping area

2131‧‧‧First conductive layer

2133‧‧‧Second conductive layer

2135‧‧‧ Third conductive layer

23‧‧‧ Circuit board

231‧‧‧ clearance area

233‧‧‧ Grounding layer

235‧‧‧Grounding wire

2371‧‧‧First signal feed line

2373‧‧‧second signal feed line

27‧‧‧ Connection unit

30‧‧‧Antenna device

31‧‧‧loop antenna

311‧‧‧Substrate

312‧‧ ‧ overlap zone

3131‧‧‧First conductive layer

3133‧‧‧Second conductive layer

3135‧‧‧ Third conductive layer

33‧‧‧Circuit board

331‧‧‧ clearance area

333‧‧‧ Grounding layer

335‧‧‧ Grounding wire

337‧‧‧ signal feed line

37‧‧‧ Connection unit

Fig. 1 is a perspective view showing a first embodiment of an antenna device capable of reducing metal shadowing effect.

Fig. 2 is a plan view showing a first embodiment of the antenna device which can reduce the metal shadowing effect of the present invention.

Fig. 3 is a perspective view showing an embodiment of a loop antenna of an antenna device capable of reducing metal shadowing effect.

Fig. 4 is a perspective view showing still another embodiment of the loop antenna of the antenna device of the present invention which can reduce the metal shadowing effect.

Fig. 5 is a perspective view showing a second embodiment of the antenna device which can reduce the metal shielding effect.

Fig. 6 is a perspective view showing a third embodiment of the antenna device which can reduce the metal shielding effect.

Figure 7 is a plan view of a third embodiment of the antenna device of the present invention which can reduce the metal shadowing effect.

Fig. 8 is a perspective view showing still another embodiment of the loop antenna of the antenna device of the present invention which can reduce the metal shadowing effect.

Fig. 9 is a perspective view showing a fourth embodiment of the antenna device which can reduce the metal shielding effect.

Fig. 10 is a plan view showing a fourth embodiment of the antenna device which can reduce the metal shadowing effect of the present invention.

Fig. 11 is a perspective view showing still another embodiment of the loop antenna of the antenna device which can reduce the metal shielding effect.

1 and 2 are respectively a perspective view and a plan view of an embodiment of an antenna device capable of reducing metal shielding effects. As shown in the figure, the antenna device 10 of the present invention can be used to transmit and receive radio frequency signals, and includes at least one loop antenna 11, a circuit board 13, at least one metal shield 15 and a plurality of connecting units 17, wherein the circuit board 13 is used to carry the loop antenna 11.

The circuit board 13 includes at least one clearance area 131 and a ground layer 133. The ground layer 133 is made of a material having a conductive property, such as metal, and the clearance area 131 is for accommodating the loop antenna 11. In order to facilitate the representation in the drawings, the first drawing of the present invention mainly places the ground layer 133 on the surface of the circuit board 13, but actually the ground layer 133 does not have to be provided on the surface of the circuit board 13. In other embodiments of the present invention, the ground layer 133 may be disposed on the surface or inside of the circuit board 13, for example, the circuit board 13 may be a multi-layer structure, and the ground layer 133 may be disposed in the structure inside the circuit board 13.

The loop antenna 11 is disposed in the clearance area 131 of the circuit board 13. The clearance area 131 is an area in which the ground layer 133 is not provided. For example, in the configuration of FIG. 1, the ground layer 133 is not provided on a specific area of the circuit board 13 to form the clearance area 131. In an embodiment of the present invention, the ground plane 133 is not disposed in the vertical extension position of the clearance area 131 of the circuit board 13. For example, the ground layer 133 or the circuit is not disposed below or above the clearance area 131.

The loop antenna 11 of the present invention can generate a capacitive effect, wherein the loop antenna 11 includes at least one substrate 111 and a plurality of conductive layers 1131/1333, and the substrate 111 is made of a material having no conductive property. A plurality of conductive layers 1131/1333 are disposed on the surface or inside of the substrate 111, wherein a capacitance effect and/or a coupling effect are formed between the plurality of conductive layers 1131/1333, and a resonant frequency of the loop antenna 11 is generated. For example, the loop antenna 11 includes a first conductive layer 1131 and a second conductive layer 1133 disposed on the surface or inside of the substrate 111, wherein a capacitive effect is generated between the first conductive layer 1131 and the second conductive layer 1133, and a loop antenna is formed. The resonant frequency of 11.

In an embodiment of the present invention, please refer to FIG. 3 for the present invention. A schematic diagram of an embodiment of the loop antenna 11 includes a substrate 111, a first conductive layer 1131 and a second conductive layer 1133. The first conductive layer 1131 and the second conductive layer 1133 are respectively disposed in different A plane or a height, for example, the first conductive layer 1131 is disposed on the upper surface of the substrate 111, and the second conductive layer 1133 is disposed on the lower surface of the substrate 111. A portion of the first conductive layer 1131 overlaps with a portion of the second conductive layer 1133 and forms an overlap region 112, so that a capacitive effect and/or a coupling effect may be generated between the first conductive layer 1131 and the second conductive layer 1133, and formed. The resonant frequency of the loop antenna 11.

For the convenience of explanation, in the embodiment described in FIG. 3 of the present invention, The first conductive layer 1131 and the second conductive layer 1133 are respectively disposed on the upper surface and the lower surface of the substrate 111. However, the positions of the first conductive layer 1131 and the second conductive layer 1133 are not limited to the substrate. The upper surface and the lower surface of the 111, the first conductive layer 1131 and the second conductive layer 1133 may be respectively disposed on the left and right surfaces of the substrate 111, or may be respectively disposed on the front surface and the rear surface of the substrate 111. Of course, in different embodiments, the first conductive layer 1131 and the second conductive layer 1133 may also be disposed inside the substrate 111. The main feature of the loop antenna 11 described in FIG. 3 is that the set height or the set plane of the first conductive layer 1131 and the second conductive layer 1133 are not Similarly, a portion of the first conductive layer 1131 overlaps a portion of the second conductive layer 1133.

In still another embodiment of the present invention, please refer to FIG. 4, which is a new A schematic diagram of a further embodiment of the loop antenna 11 includes a substrate 111, a first conductive layer 1131 and a second conductive layer 1133, wherein the first conductive layer 1131 and the second conductive layer 1133 are disposed on the base The same or similar plane or height of the material 111, for example, the first conductive layer 1131 and the second conductive layer 1133 are all disposed on the upper surface of the substrate 111. The first conductive layer 1131 and the second conductive layer 1133 do not contact each other on the substrate 111, and a gap 114 exists between the first conductive layer 1131 and the second conductive layer 1133, so the first conductive layer 1131 and the second conductive layer A capacitive effect and/or a coupling effect can be generated between the layers 1133 and form the resonant frequency of the loop antenna 11.

For the convenience of explanation, in the embodiment described in FIG. 4 of the present invention, The configuration in which the first conductive layer 1131 and the second conductive layer 1133 are disposed on the upper surface of the substrate 111 is described. However, the positions at which the first conductive layer 1131 and the second conductive layer 1133 are disposed are not limited to the upper surface of the substrate 111. The first conductive layer 1131 and the second conductive layer 1133 are respectively disposed on the left surface, the right surface, the front surface, or the rear surface of the substrate 111. Of course, in different embodiments, the first conductive layer 1131 and the second conductive layer 1133 may also be disposed inside the substrate 111. The main feature of the loop antenna 11 described in FIG. 4 is that the first conductive layer 1131 and the second conductive layer 1133 are disposed on the same or similar plane or height of the substrate 111, and are disposed on the first conductive layer 1131 and the second conductive layer. There is a gap 114 between the layers 1133.

The circuit board 13 further includes a plurality of ground lines 135 and at least one signal feed line 137, wherein the grounding wires 135 are respectively connected to the respective conductive layers 1131/1133 of the loop antenna 11, and the signal feeding wires 137 are connected to the at least one conductive layer 1131/1133 of the loop antenna 11. Figure 3 For example, the loop antenna 11 described in FIG. 4 is connected to the first conductive layer 1131 and the second conductive layer 1133 of the loop antenna 11, and the signal feed line 137 is connected to the first conductive layer 1131 of the loop antenna 11. .

In the novel embodiment, the antenna structure 10 further includes at least one metal shield. 15. The distance between the metal shield 15 and the circuit board 13 is similar, and there is a first spacing d1 between the metal shield 15 and the circuit board 13, for example, the first spacing d1 is greater than 0.3 mm. Of course, the first spacing d1 does not have to be greater than 0.3 mm. The present invention can also be applied to a configuration in which the first spacing d1 is less than or equal to 0.3 mm. Since the metal shield 15 is adjacent to the circuit board 13, it may have a shielding effect on the loop antenna 11, thereby affecting the efficiency of the loop antenna 11 transmitting or receiving the RF signal.

In an embodiment of the present invention, the metal shield 15 may be an antenna structure. The outer casing of the electronic device 10, such as the antenna structure 10 and/or the loop antenna 11, is disposed in a mobile phone or a smart phone, and the metal shield 15 is a metal case of a mobile phone and/or a smart phone, and the loop antenna 11 is The metal casing of the mobile phone and/or the smart phone is shielded and causes the loop antenna 11 to receive or transmit radio frequency signals with reduced efficiency.

Of course, mobile phones and smart phones are only illustrative examples, not the present invention. The antenna structure 10 of the present invention can be applied to any electronic device that needs to receive and/or transmit an RF signal through an antenna. In addition, the metal cover 15 is not limited to the metal casing of the mobile phone and/or the smart phone. The metal cover 15 can also be a component of a mobile phone, a smart phone and/or other electronic devices, in other words, a metal shield. The position set in the electronic device 15 is not a limitation of the present invention.

In order to avoid the shadowing effect of the metal shield 15 on the loop antenna 11, this The antenna structure 10 of the present invention further includes a plurality of connecting units 17 and is electrically connected to the grounding wire 135, the metal shield 15 and the grounding layer 133 through the connecting unit 17. The connecting unit 17 can be made of a material having conductive properties, such as metal, such that the metal shield 15 is electrically connected to the ground layer 133 and the ground line 135.

Taking the first and second figures as an example, the first conductive layer 1131 of the loop antenna 11 The grounding layer 133 is connected to the grounding layer 133. The grounding layer 133 is connected to the metal shield 15 through the connecting unit 17, and the second conductive layer 1133 of the loop antenna 11 is connected to the metal shield 15 through the grounding wire 135 and the connecting unit 17.

Taking FIG. 5 as an example, the first conductive layer 1131 of the loop antenna 11 is grounded. The line 135 is connected to the ground layer 133. The ground layer 133 is connected to the metal shield 15 through a plurality of connecting units 17, and the second conductive layer 1133 of the loop antenna 11 is connected to the metal shield 15 through the grounding line 135 and the connecting unit 17, for example, The ground layer 133 can be connected to the metal shield 15 through the two connecting units 17. The number of the connecting units 17 of the grounding layer 133 and the metal shielding 15 is not limited to two, and may be two or more.

The main feature of the present invention is that the respective conductive layers of the loop antenna 11 are made 1131/1133, the grounding layer 133, the metal shielding 15 and/or the connecting unit 17 are electrically connected to each other to reduce the shielding effect caused by the metal shielding 15 on the loop antenna 11. As for the respective conductive layers 1131/1133, The electrical connection sequence between the formation 133, the metal shield 15 and/or the connection unit 17 is not the focus of the present invention and is not a limitation of the present invention.

In an embodiment of the present invention, the loop antenna 11 includes a first conductive layer 1131. And the second conductive layer 1133, and the first conductive layer 1131 and the second conductive layer 1133 are respectively connected to the ground layer 133 and/or the metal shield 15 through different connection units 17. Two connection units 17 There is a second spacing d2, wherein the length of the second spacing d2 is greater than or equal to 1/8 of the wavelength of the RF signal transmitted or received by the loop antenna 11, for example greater than or equal to 1/8 of the maximum wavelength of the resonant frequency of the loop antenna 11. According to the antenna structure 10 constructed in this embodiment, the influence of the metal shield 15 on the radiation efficiency of the loop antenna 11 can be significantly reduced, so that the loop antenna 11 can exert the maximum effect. Of course, the length of the second spacing d2 is not necessarily greater than or equal to 1/8 of the wavelength of the RF signal transmitted or received by the loop antenna 11. If the second spacing d2 is less than 1/8 of the wavelength of the RF signal, the metal shielding can also be reduced. 15 pairs of loop antennas 11 have a shadowing effect, but the effect may be less good.

The antenna device 10 of the present invention further includes a feature of the circuit board 13 At least one grounding wire 135 is directly connected to the metal shield 15 through the connecting unit 17, and is not directly connected to the grounding layer 133. Taking the first and fifth figures as an example, the ground line 135 on the left side of the figure is directly connected to the ground layer 133, and the metal shield 15 is connected through the ground layer 133 and the connection unit 17. The grounding wire 135 located on the right side of the figure is not directly connected to the grounding layer 133, and is directly connected to the metal shield 15 through the connecting unit 17, whereby the metal shielding object 15 can effectively reduce the radiation efficiency of the loop antenna 11.

Figure 6 and Figure 7 are the antennas that can reduce the metal shadowing effect. A perspective view and a plan view of still another embodiment of the device. As shown in the figure, the antenna device 20 of the present invention can be used to transmit and receive two or more different frequency RF signals, including a loop antenna 21, a circuit board 23, at least one metal shield 15 and a plurality of A connecting unit 27, wherein the circuit board 23 is used to carry the loop antenna 21.

The circuit board 23 includes at least one clearance area 231 and a ground layer 233, wherein The empty area 231 is an area where the ground layer 233 is not provided. The ground layer 233 is made of a material having conductive properties. Made of, for example, metal. In order to facilitate the representation in the drawings, the sixth drawing of the present invention mainly places the ground layer 233 on the surface of the circuit board 23, but actually the ground layer 233 does not have to be provided on the surface of the circuit board 23. In other embodiments of the present invention, the ground layer 233 may be disposed on the surface or inside of the circuit board 23, for example, the circuit board 23 may be a multi-layered structure, and the ground layer 233 may be disposed within the structure inside the circuit board 23.

The loop antenna 21 is disposed in the clearance area 231 of the circuit board 23, wherein the clearance is The area 231 is an area where the ground layer 233 is not provided.

The loop antenna 21 of the present invention has a capacitive effect, wherein the loop antenna 21 includes at least one substrate 211 and a plurality of conductive layers 2131/2133/2135, and the substrate 211 is made of a material having no conductive property. A plurality of conductive layers 2131/2133/2135 are disposed on a surface or an inner portion of the substrate 211, wherein a capacitance effect and/or a coupling effect are generated between the plurality of conductive layers 2131/2133/2135, and a resonant frequency of the loop antenna 21 is formed. .

In an embodiment of the present invention, please refer to FIG. 8 for the present invention. A schematic diagram of an embodiment of the loop antenna 21 includes a substrate 211, a first conductive layer 2131, a second conductive layer 2133, and a third conductive layer 2135, wherein the first conductive layer 2131 and the second conductive layer The layer 2133 is disposed on the surface or inside of the substrate 211. For example, the first conductive layer 2131 and the second conductive layer 2133 may be disposed on the upper surface of the substrate 211. The third conductive layer 2135 is disposed on the surface or inside of the substrate 211, and for example, the third conductive layer 2135 may be disposed on the lower surface of the substrate 211. The plane of the third conductive layer 2135 is different from the plane or height of the first conductive layer 2131 and the second conductive layer 2133, and a portion of the third conductive layer 2135 is respectively connected with a portion of the first conductive layer 2131 and a portion of the second conductive layer. The layers 2133 overlap and form two overlapping regions 212 such that electricity can be generated between the first conductive layer 2131, the second conductive layer 2133, and the third conductive layer 2135. The capacitive effect and/or the coupling effect and form the resonant frequency of the loop antenna 21.

In the new embodiment, the third conductive layer 2135 and the first conductive layer 2131 A partial region overlaps and forms a capacitive effect to generate a first resonant frequency of the loop antenna 21, and a partial region between the third conductive layer 2135 and the second conductive layer 2133 overlaps and forms a capacitive effect to generate the loop antenna 21 The second resonant frequency. Therefore, the loop antenna 21 of the present invention can generate two or more resonant frequencies and can receive or transmit RF signals of a plurality of frequency bands.

For the convenience of explanation, in the embodiment described in FIG. 8 of the present invention, The first conductive layer 2131 and the second conductive layer 2133 are disposed on the upper surface of the substrate 211, and the third conductive layer 2135 is disposed on the lower surface of the substrate 211, but the first conductive layer 2131, the second The positions of the conductive layer 2133 and the third conductive layer 2135 are not limited to the upper surface and the lower surface of the substrate 211, and the first conductive layer 2131, the second conductive layer 2133, and the third conductive layer 2135 may be respectively disposed on the substrate. The left and right surfaces of the 211 are provided on the front and rear surfaces of the substrate 211, respectively. Of course, in different embodiments, the first conductive layer 2131, the second conductive layer 2133, and the third conductive layer 2135 may also be disposed inside the substrate 211. The loop antenna 21 of the present invention is mainly characterized in that the first conductive layer 2131 and the second conductive layer 2133 are disposed in a plane or height, and the third conductive layer 2135 is disposed in a plane or height with the first conductive layer 2131 and The second conductive layer 2133 is disposed at a different plane or height, and a portion of the third conductive layer 2135 overlaps with a portion of the first conductive layer 2131 and a portion of the second conductive layer 2133, respectively.

The circuit board 23 further includes a plurality of grounding lines 235 and a plurality of signal feeding lines. 2371/2373, wherein the grounding wire 235 is connected to each conductive layer of the loop antenna 21 2131/2133/2135. Taking the loop antenna 21 described in FIG. 8 as an example, the grounding wire 235 is respectively connected to the first conductive layer 2131, the second conductive layer 2133 and the third conductive layer 2135 of the loop antenna 21, and the signal feeding line includes the first signal feeding line. 2371 and the second signal feeding line 2373, wherein the first signal feeding line 2371 is connected to the first conductive layer 2131, and the second signal feeding line 2373 is connected to the second conductive layer 2133.

In the novel embodiment, the antenna structure 20 further includes at least one metal shield. 15. The distance between the metal shield 15 and the circuit board 23 is similar, and there is a first spacing d1 between the metal shield 15 and the circuit board 23, for example, the first spacing d1 is greater than 0.3 mm. Of course, the first spacing d1 does not have to be greater than 0.3 mm. The present invention can also be applied to a configuration in which the first spacing d1 is less than or equal to 0.3 mm. The metal shield 15 is adjacent to the circuit board 23 and may have a Shielding effect on the loop antenna 21, thereby affecting the efficiency of the loop antenna 21 to transmit or receive RF signals.

In an embodiment of the present invention, the metal shield 15 may be an antenna structure. The outer casing of the electronic device 20, such as the metal shield 15, may be a metal casing of a mobile phone and/or a smart phone, and the antenna structure 20 and/or the loop antenna 21 disposed in the mobile phone or the smart phone may be used by the mobile phone and/or Or the metal casing of the smart phone is shielded, and the efficiency of the loop antenna 21 receiving or transmitting the radio frequency signal is reduced. Of course, the mobile phone and the smart phone are only the illustrated embodiments, and are not limited by the antenna structure 20 of the present invention. The content described in the present invention can be applied to any electronic device that needs to receive and/or transmit radio frequency signals through the antenna. In addition, the metal cover 15 is not limited to the metal casing of the mobile phone and/or the smart phone. The metal cover 15 can also be a component of a mobile phone, a smart phone and/or other electronic devices, in other words, a metal shield. The position set in the electronic device 15 is not a limitation of the present invention.

In order to prevent the metal shield 15 from shielding the loop antenna 21, the antenna structure 20 of the present invention further includes a plurality of connecting units 27, and is electrically connected to the metal shield 15, the grounding line 235, and the grounding layer 233 through the connecting unit 27. . The connecting unit 27 can be made of a material having conductive properties, such as metal, such that the metal shield 15 is electrically connected to the ground layer 233 and the ground line 235.

In the present embodiment, the first conductive layer 2131 of the loop antenna 21 is connected to the ground layer 233 through the grounding line 235, and the ground layer 233 is connected to the metal shield 15 through the connecting unit 27. The second conductive layer 2133 of the loop antenna 21 is connected to the ground layer 233 through the ground line 235, and the ground layer 233 is connected to the metal shield 15 through the connection unit 27. The third conductive layer 2135 of the loop antenna 21 is connected to the metal shield 15 through the ground line 235 and the connection unit 27.

In an embodiment of the present invention, the loop antenna 21 includes a first conductive layer 2131, a second conductive layer 2133, and a third conductive layer 2135, and the first conductive layer 2131, the second conductive layer 2133, and the third conductive layer 2135 are respectively transmitted through Different connection units 27 connect the metal shield 15 and/or the ground layer 233. The number of the connecting units 27 may be three, wherein a second spacing d2 and a third spacing d3 exist between the adjacent or adjacent connecting units 27, and the length of the second spacing d2 is greater than or equal to the number of the loop antennas 21. The length of the third wavelength d3 is greater than or equal to 1/8 of the maximum wavelength of the second resonant frequency of the loop antenna 21. According to the antenna structure 20 constructed in this embodiment, the influence of the metal shield 15 on the radiation efficiency of the loop antenna 21 can be significantly reduced, so that the loop antenna 21 exerts the maximum effect. Of course, the length of the second spacing d2 does not have to be greater than or equal to 1/8 of the maximum wavelength of the first resonant frequency of the loop antenna 21; and the length of the third spacing d3 does not have to be greater than or equal to the second of the loop antenna 21. 1/8 of the maximum wavelength of the resonant frequency. If the second spacing d2 is smaller than the maximum of the first resonant frequency When 1/8 of the wavelength, or the third pitch d3 is less than 1/8 of the maximum wavelength of the second resonance frequency, the shadowing effect of the metal shield 15 on the loop antenna 21 can also be reduced, but the effect may be less favorable.

The present invention is characterized in that the respective conductive layers of the loop antenna 21 are made 2131/2133/2135, the ground layer 233, the metal shield 15 and/or the connecting unit 27 are electrically connected to each other to reduce the shadowing effect of the metal shield 15 on the loop antenna 21, as for the respective conductive layers 2131/2133 The electrical connection sequence between /2135, ground plane 233, metal shield 15 and/or connection unit 27 is not the focus of the present invention and is not a limitation of the present invention.

The antenna device 20 of the present invention further includes a feature of the circuit board 23 At least one grounding wire 235 is directly connected to the metal shield 15 through the connecting unit 27, and is not directly connected to the grounding layer 233. Taking the figure 6 as an example, the grounding wire 235 located on the left and right sides of the loop antenna 21 is directly connected to the grounding layer 233, for example, the grounding wire 235 connecting the first conductive layer 2131 and the second conductive layer 2133, and is transmitted through the grounding layer 233 and the connecting unit. 27 connects the metal shield 15. The grounding wire 235 located at the center of the loop antenna 21 is not directly connected to the grounding layer 233, for example, the grounding wire 235 of the third conductive layer 2135 is connected, but the metal shielding 15 is directly connected through the connecting unit 27, thereby effectively reducing metal shielding. The object 15 affects the radiation efficiency of the loop antenna 21.

Figure 9 and Figure 10 are the antennas that can reduce the metal shadowing effect. A perspective view and a plan view of still another embodiment of the device. As shown in the figure, the antenna device 30 of the present invention can be used to transmit and receive two or more different frequency RF signals, including a loop antenna 31, a circuit board 33, at least one metal shield 15 and a plurality of A connecting unit 37, wherein the circuit board 33 is used to carry the loop antenna 31.

The circuit board 33 includes at least one clearance area 331 and a ground layer 333, wherein The empty area 331 is an area where the ground layer 333 is not provided. The ground layer 333 is made of a material having a conductive property, such as a metal. In order to facilitate the representation in the drawings, the ninth diagram of the present invention mainly places the ground layer 333 on the surface of the circuit board 33, but actually the ground layer 333 does not have to be provided on the surface of the circuit board 33. In other embodiments of the present invention, the ground layer 333 may be disposed on the surface or inside of the circuit board 33. For example, the circuit board 33 may be a multi-layer structure, and the ground layer 333 may be disposed in the structure inside the circuit board 33.

The loop antenna 31 is disposed in the clearance area 331 of the circuit board 33, wherein The empty area 331 is an area where the ground layer 333 is not provided.

The loop antenna 31 of the present invention has a capacitive effect, wherein the loop antenna 31 includes at least one substrate 311 and a plurality of conductive layers 3131/3133/3135, and the substrate 311 is made of a material having no conductive property. A plurality of conductive layers 3131/3133/3135 are disposed on the surface or inside of the substrate 311, wherein a plurality of conductive layers 3131/3133/3135 can generate a capacitive effect and/or a coupling effect, and form a resonant frequency of the loop antenna 31. .

In an embodiment of the present invention, please refer to FIG. 11 for the present invention. A schematic diagram of an embodiment of the loop antenna 31 includes a substrate 311, a first conductive layer 3131, a second conductive layer 3133, and a third conductive layer 3135, wherein the first conductive layer 3131 and the second conductive layer The layer 3133 is disposed on the surface or inside of the substrate 311. For example, the first conductive layer 3131 and the second conductive layer 3133 may be disposed on the upper surface of the substrate 311. The third conductive layer 3135 is disposed on the surface or inside of the substrate 311, and for example, the third conductive layer 3135 may be disposed on the lower surface of the substrate 311. The plane of the third conductive layer 3135 is different from the plane or height of the first conductive layer 3131 and the second conductive layer 3133, and a part of the third conductive layer 3135 is respectively connected with a portion of the first conductive layer 3131 and a portion of the second conductive layer. Layers 3133 overlap and form two overlapping regions 312, A capacitive effect and/or a coupling effect may be generated between the first conductive layer 3131, the second conductive layer 3133, and the third conductive layer 3135, and the resonant frequency of the loop antenna 31 is formed.

In the novel embodiment, the third conductive layer 3135 and the first conductive layer 3131 A partial region overlaps and forms a capacitive effect to generate a first resonant frequency of the loop antenna 31, and a partial region between the third conductive layer 3135 and the second conductive layer 3133 overlaps and forms a capacitive effect to generate the loop antenna 31. The second resonant frequency. Therefore, the loop antenna 31 of the present invention can generate two or more resonant frequencies and can receive or transmit RF signals of a plurality of frequency bands.

For the convenience of explanation, in the embodiment described in FIG. 11 of the present invention, A configuration in which the first conductive layer 3131 and the second conductive layer 3133 are disposed on the upper surface of the substrate 311 and the third conductive layer 3135 is disposed on the lower surface of the substrate 311 is described, however, the first conductive layer 3131, the second The positions of the conductive layer 3133 and the third conductive layer 3135 are not limited to the upper surface and the lower surface of the substrate 311, and the first conductive layer 3131, the second conductive layer 3133, and the third conductive layer 3135 may be respectively disposed on the substrate. The left and right surfaces of the 311 are disposed on the front and rear surfaces of the substrate 311, respectively. Of course, in different embodiments, the first conductive layer 3131, the second conductive layer 3133, and the third conductive layer 3135 may also be disposed inside the substrate 311. The loop antenna 31 of the present invention is mainly characterized in that the first conductive layer 3131 and the second conductive layer 3133 are disposed at a similar plane or height, and the third conductive layer 3135 is disposed at a plane or height with the first conductive layer 3131 and The second conductive layer 3133 is disposed at a different plane or height, and a portion of the third conductive layer 3135 overlaps with a portion of the first conductive layer 3131 and a portion of the second conductive layer 3133, respectively.

The circuit board 33 further includes a plurality of ground lines 335 and a signal feed line 337. The grounding wires 335 are respectively connected to the respective conductive layers 3131/3133/3135 of the loop antenna 31. Taking the loop antenna 31 described in FIG. 11 as an example, the grounding wire 335 is respectively connected to the first conductive layer 3131, the second conductive layer 3133 and the third conductive layer 3135 of the loop antenna 31, and the signal feeding line 337 is connected to the third conductive layer. Layer 3135.

In the novel embodiment, the antenna structure 30 further includes at least one metal shield. 15. The distance between the metal shield 15 and the circuit board 33 is similar, and there is a first spacing d1 between the metal shield 15 and the circuit board 33, for example, the first spacing d1 is greater than 0.3 mm. Of course, the first spacing d1 does not have to be greater than 0.3 mm. The present invention can also be applied to a configuration in which the first spacing d1 is less than or equal to 0.3 mm. The metal shield 15 is adjacent to the circuit board 33 and may have a Shielding effect on the loop antenna 31, thereby affecting the efficiency with which the loop antenna 31 transmits or receives RF signals.

In an embodiment of the present invention, the metal shield 15 may be an antenna structure. The outer casing of the electronic device of 30, such as the metal shield 15, may be a metal casing of a mobile phone and/or a smart phone, and may be disposed on the antenna structure 30 of the mobile phone or the smart phone and/or the loop antenna 31, possibly by the mobile phone and / or the metal casing of the smart phone is shielded, and the efficiency of the loop antenna 31 receiving or transmitting the radio frequency signal is reduced. Of course, the mobile phone and the smart phone are only the illustrated embodiments, and are not limited by the antenna structure 30 of the present invention. The content described in the present invention can be applied to any electronic device that needs to receive and/or transmit radio frequency signals through the antenna. In addition, the metal cover 15 is not limited to the metal casing of the mobile phone and/or the smart phone. The metal cover 15 can also be a component of a mobile phone, a smart phone and/or other electronic devices, in other words, a metal shield. The position set in the electronic device 15 is not a limitation of the present invention.

In order to avoid the shadowing effect of the metal shield 15 on the loop antenna 31, The antenna structure 30 further includes a plurality of connecting units 37, and is electrically connected to the metal shield 15, the grounding wire 335, and the grounding layer 333 through the connecting unit 37. The connecting unit 37 can be made of a material having conductive properties, such as metal, such that the metal shield 15 is electrically connected to the ground layer 333 and the ground line 335.

In the new embodiment, the first conductive layer 3131 of the loop antenna 31 is transparent. The ground line 335 is connected to the ground layer 333, and the ground layer 333 is connected to the metal shield 15 through the connection unit 37. The second conductive layer 3133 of the loop antenna 31 is connected to the ground layer 333 through the ground line 335, and the ground layer 333 is connected to the metal shield 15 through the connection unit 37. The third conductive layer 3135 of the loop antenna 31 is connected to the metal shield 15 through the ground line 335 and the connection unit 37.

In an embodiment of the present invention, the loop antenna 31 includes a first conductive layer 3131. The second conductive layer 3133 and the third conductive layer 3135, and the first conductive layer 3131, the second conductive layer 3133, and the third conductive layer 3135 are respectively connected to the metal shield 15 and/or the ground layer 333 through different connection units 37. The number of the connecting units 37 may be three, and a second spacing d2 and a third spacing d3 exist between adjacent or adjacent connecting units 37. The length of the second pitch d2 is greater than or equal to 1/8 of the maximum wavelength of the first resonant frequency of the loop antenna 31, and the length of the third pitch d3 is greater than or equal to 1/ of the maximum wavelength of the second resonant frequency of the loop antenna 31. 8. According to the antenna structure 30 constructed in this embodiment, the influence of the metal shield 15 on the radiation efficiency of the loop antenna 31 can be significantly reduced, so that the loop antenna 31 exerts the maximum effect. Of course, the second spacing d2 does not necessarily have to be greater than or equal to 1/8 of the maximum wavelength of the first resonant frequency of the loop antenna 31; and the third spacing d3 does not necessarily have a length greater than or equal to the second resonance of the loop antenna 31. 1/8 of the maximum wavelength of the frequency. If the second pitch d2 is less than 1/8 of the maximum wavelength of the first resonance frequency or the third pitch d3 is less than 1/8 of the maximum wavelength of the second resonance frequency, the same can be lowered. The shadowing effect of the low metal shield 15 on the loop antenna 31 may only be less effective.

The present invention is characterized in that the respective conductive layers of the loop antenna 31 are made 3131/3133/3135, the grounding layer 333, the metal shield 15 and/or the connecting unit 37 are electrically connected to each other to reduce the shielding effect caused by the metal shielding 15 on the loop antenna 31. As for the respective conductive layers 3131/3133 /3135, the electrical connection sequence between the ground layer 333, the metal shield 15 and/or the connection unit 37 is not the focus of the present invention, nor is it a limitation of the present invention.

For convenience of representation, in the first, fifth, sixth, and ninth The metal shield 15 is disposed below the circuit board 13/23/33 as an embodiment of the present invention, but in practical applications, the metal shield 15 is not disposed below the circuit board 13/23/33. The metal shield 15 may also be disposed above, to the left, to the right, to the front, and/or to the rear of the circuit board 13/23/33 and/or the loop antenna 11/21/31.

In addition, for the convenience of explanation, the present invention mainly uses a metal shield. 15 is an illustrative embodiment, but in actual application, the number of metal shields 15 may also be plural. When disposed, a plurality of metal shields 15 are electrically connected to the ground layer 133 by the connection unit 17/27/37. 233/333 and/or grounding wire 135/235/335 can reduce the shadowing effect of the plurality of metal shields 15 on the loop antenna 11/21/31.

The antenna device 30 of the present invention further includes a feature of the circuit board 33 At least one grounding wire 335 is directly connected to the metal shield 15 through the connecting unit 37, and is not directly connected to the grounding layer 333. Taking the ninth figure as an example, the grounding wire 335 located on the left and right sides of the loop antenna 31 is directly connected to the grounding layer 333, for example, the grounding wire 335 connecting the first conductive layer 3131 and the second conductive layer 3133, and is transmitted through the grounding layer 333 and the connecting unit. 37 connects the metal shield 15. Located in the loop The grounding wire 335 at the central position of the antenna 31 is not directly connected to the grounding layer 333, for example, the grounding wire 335 of the third conductive layer 3135 is connected, but the metal shielding 15 is directly connected through the connecting unit 37, thereby effectively reducing the metal shielding 15 The radiation efficiency of the loop antenna 31 is affected.

Although the embodiments of the present invention are disclosed as described above, it is not intended to limit the present invention, and those skilled in the art can, without departing from the spirit and scope of the present invention, the shapes, structures, and features described in the scope of the present application. And the number of the patents may be changed, and the scope of patent protection of the present invention is subject to the scope of the patent application attached to the specification.

The connecting unit provided in the present invention is a device capable of establishing an electrical connection, and is not limited to its existence, and may be a metal wire, a conductive material, a metal dome or a thimble, and may be fixed to the circuit in structure. The board or metal shield or both can be attached to the outside of the board or embedded inside the board, or combined with the board through hole and the metal member.

10‧‧‧Antenna device

11‧‧‧loop antenna

1131‧‧‧First conductive layer

1133‧‧‧Second conductive layer

13‧‧‧Circuit board

131‧‧‧ clearance area

133‧‧‧ Grounding layer

135‧‧‧ Grounding wire

137‧‧‧ signal feed line

15‧‧‧Metal shelter

17‧‧‧ Connection unit

Claims (18)

An antenna device for reducing a metal shadowing effect, for transmitting or receiving an RF signal, comprising: at least one loop antenna, comprising: at least one substrate; a plurality of conductive layers disposed on a surface or an interior of the substrate, wherein the plurality a capacitive effect is formed between the conductive layers, and a resonant frequency of the loop antenna is generated; a circuit board carrying the loop antenna includes: a ground layer; a clearing area for accommodating the loop antenna; and a plurality of grounding lines Connecting each conductive layer of the loop antenna; at least one signal feed line connecting at least one conductive layer of the loop antenna; at least one metal shield adjacent to the loop antenna, wherein the metal shield exists between the metal shield and the loop antenna a first spacing; and a plurality of connecting units electrically connecting the metal shield, the ground layer, and the grounding line. The antenna device of claim 1, wherein the first pitch has a length greater than 0.3 mm. The antenna device of claim 1, wherein a second spacing exists between adjacent connecting units, and the length of the second spacing is greater than or equal to 1/8 of a maximum wavelength of a resonant frequency of the loop antenna. The antenna device of claim 1, wherein at least one grounding wire of the circuit board directly connects the metal shield through the connecting unit. An antenna device for reducing a metal shadowing effect, for transmitting or receiving an RF signal, comprising: at least one loop antenna comprising: at least one substrate; at least one first conductive layer disposed on a surface or an interior of the substrate; a second conductive layer disposed on a surface or an inner portion of the substrate, wherein the first conductive layer The layer and the second conductive layer are used to generate a capacitive effect and form a resonant frequency of the loop antenna; a circuit board carrying the loop antenna and comprising: a ground layer; and a clearance area for accommodating the loop An antenna; a plurality of grounding wires respectively connected to the first conductive layer and the second conductive layer of the loop antenna; at least one signal feeding line connecting the first conductive layer of the loop antenna; at least one metal shield adjacent to the antenna a loop antenna, wherein a first spacing exists between the metal shield and the loop antenna; and a plurality of connecting units electrically connecting the metal shield, the ground layer, and the ground line. The antenna device of claim 5, wherein the first pitch has a length greater than 0.3 mm. The antenna device of claim 5, wherein a second spacing exists between adjacent connecting units, and the length of the second spacing is greater than or equal to 1/8 of a maximum wavelength of a resonant frequency of the loop antenna. The antenna device of claim 5, wherein the first conductive layer and the second conductive layer are respectively disposed on different planes, and a portion of the first conductive layer overlaps with a portion of the second conductive layer to generate a capacitor Effect and form the resonant frequency of the loop antenna. The antenna device of claim 5, wherein the first conductive layer and the second conductive layer are disposed on the same or similar planes, and a first layer between the first conductive layer and the second conductive layer exists The gap, the first conductive layer and the second conductive layer are used to generate a capacitive effect and form a resonant frequency of the loop antenna. The antenna device of claim 5, wherein at least one grounding wire of the circuit board directly connects the metal shield through the connecting unit. An antenna device for reducing a metal shadowing effect, for transmitting or receiving radio frequency signals of a plurality of frequency bands, comprising: at least one loop antenna, comprising: At least one substrate; at least one first conductive layer disposed on a surface or an inner portion of the substrate; at least one second conductive layer disposed on a surface or an inner portion of the substrate; at least one third conductive layer disposed on the base The surface of the material or the interior of the material, the plane of the third conductive layer is different from the plane of the first conductive layer or the second conductive layer, and a portion of the third conductive layer and the portion of the first conductive layer and the portion respectively The two conductive layers overlap, wherein a capacitance effect is formed between the first conductive layer and the third conductive layer, and a first resonant frequency of the loop antenna is generated, and a capacitance is formed between the second conductive layer and the third conductive layer And generating a second resonant frequency of the loop antenna; a circuit board carrying the loop antenna, and comprising: a ground layer; a clearing area for accommodating the loop antenna; and a plurality of grounding lines respectively connected to the loop a first conductive layer, a second conductive layer and a third conductive layer; a first signal feed line connecting the first conductive layer of the loop antenna; a second signal feed line connecting the second conductive layer of the loop antenna At least one metal shield, adjacent to the loop antenna, wherein a first spacing is present between the metal shield and the loop antenna; and a plurality of connection means electrically connected to the metal shield, the ground layer and the ground line. The antenna device of claim 11, wherein the first pitch has a length greater than 0.3 mm. The antenna device of claim 11, wherein the adjacent connecting unit has a second pitch and a third pitch, and the length of the second pitch is greater than or equal to the first resonance of the loop antenna. The length of the third wavelength is greater than or equal to 1/8 of the maximum wavelength of the second resonant frequency of the loop antenna. The antenna device of claim 11, wherein at least one grounding wire of the circuit board directly connects the metal shield through the connecting unit. An antenna device for reducing a metal shadowing effect, for transmitting or receiving a plurality of frequency band RF signals, comprising: at least one loop antenna comprising: at least one substrate; at least one first conductive layer disposed on a surface of the substrate Or at least one second conductive layer disposed on a surface or an inner portion of the substrate; at least one third conductive layer disposed on a surface or an inner portion of the substrate, the third conductive layer disposed on a plane and the first conductive layer The layer or the second conductive layer is disposed in a different plane, and a portion of the third conductive layer overlaps with a portion of the first conductive layer and a portion of the second conductive layer, respectively, wherein between the first conductive layer and the third conductive layer Forming a capacitive effect and generating a first resonant frequency of the loop antenna, and a capacitive effect is formed between the second conductive layer and the third conductive layer, and generating a second resonant frequency of the loop antenna; a circuit board carrying the The loop antenna includes: a grounding layer; a clearing area for accommodating the loop antenna; and a plurality of grounding lines respectively connected to the first conductive layer, the second conductive layer and the third of the loop antenna An electrical layer; a signal feed line connecting the third conductive layer of the loop antenna; at least one metal shield adjacent to the loop antenna, wherein a first spacing exists between the metal shield and the loop antenna; and a plurality of connections The unit electrically connects the metal shield, the ground layer, and the ground line. The antenna device of claim 15, wherein the first pitch has a length greater than 0.3 mm. The antenna device of claim 15, wherein a second spacing and a third spacing exist between the adjacent connecting units, and the length of the second spacing is greater than or equal to the first resonance of the loop antenna. The length of the third wavelength is greater than or equal to 1/8 of the maximum wavelength of the second resonant frequency of the loop antenna. The antenna device of claim 15, wherein at least one grounding wire of the circuit board directly connects the metal shield through the connecting unit.