TWI462392B - Multi-antenna system and an electronic device having the same - Google Patents

Description

Multi-antenna system and electronic device having the same

The present invention relates to an antenna system, and more particularly to a multi-antenna system of high gain and high directivity.

Since current wireless network products are mostly demanding in terms of lightness, shortness and convenience, how to design a small antenna that meets the needs of use has become one of the key technologies for wireless network products to effectively reduce the size; in particular, the design of small antennas is Wireless network products, such as the wireless network bridge (access point, AP) signal reception capability and quality have the most direct relationship, so that how to get the proper antenna performance under the limited space configuration of wireless network products Performance has always been the primary issue for related industries.

However, most of the antennas used in wireless network bridges are three-dimensional (3-D) stereoscopic structures, such as the multi-input and multi-output dual-frequency monopole antenna disclosed in the Republic of China Patent No. M377714. "Device", but such an antenna occupies a large space and needs to be connected to an antenna ground plane, so that the space available in the wireless network bridge is limited. In addition, the antenna design of the traditional 3-D three-dimensional metal structure requires a plurality of bending of the antenna radiating element, which is cumbersome in the process and high in manufacturing cost. In addition, even if a short-circuit monopole antenna or a Planar Inverted-F Antenna (PIFA) is used, the maximum gain of the antenna in the 2.4 GHz and 5 GHz bands is only 3 and 4 dBi, respectively, and the antenna radiation pattern is It is not broadside radiation and cannot meet the needs of high gain and high directivity.

Accordingly, it is an object of the present invention to provide a multi-antenna system that achieves dual frequency operation and has high directivity and high gain.

Another object of the present invention is to provide a built-in dual-frequency multi-antenna system that is small in size, low in cost, low-profile, and can be applied to a small outdoor wireless network bridge to maintain The integrity and aesthetics of the overall appearance of the product.

Thus, the multi-antenna system of the present invention comprises an antenna module and a system module. The antenna module includes an antenna substrate and a plurality of planar dipole antennas. The antenna substrate includes a first surface and a second surface opposite to the first surface. The planar dipole antennas are disposed on the first surface of the antenna substrate. And each of the planar dipole antennas includes a shorting section having a grounding end, a first radiating arm that provides a first operating frequency band, and a second radiating arm that provides a second operating frequency band. a radiating arm is respectively connected to both ends of the short-circuiting section, the second radiating arms respectively have a feeding section connected to the short-circuiting section, and an extending section extending from the end of the feeding section, wherein the second radiating arms are a feed end, the feed end of the planar dipole antenna, the ground end and the geometric center defined by the planar dipole antennas are in the same straight line, and the geometric center of the planar dipole antenna and the plane The distance between the geometric centers defined by the dipole antennas is the same, and the shortest distance between any two adjacent planar dipole antennas is the same, so that the antenna of the symmetrical structure keeps the same Isolation (isolation), and so that each planar dipole antenna having a more symmetrical signal space to cover in the space.

The system module includes at least one ground plane facing the second surface of the antenna substrate, and the system module is spaced apart from the second surface of the antenna substrate by a distance, and the ground plane provides a system ground plane of the RF circuit on the system circuit board. And for reflecting the radiation of the planar dipole antennas, the antenna module has a high directivity, and the antenna gain of the antenna module in a single direction is improved.

Preferably, the two first radiating arms of each of the planar dipole antennas are respectively connected to both ends of the short-circuiting section and extend away from the extending direction (Y-axis direction) of the short-circuiting section, and the two second radiating arms respectively have one a feed section connected to the short-circuit section, and an extension connected to the end of the feed section and extending parallel to the extension direction of the short-circuit section, the feed end being located on one of the feed sections.

Preferably, the antenna substrate further includes a through hole at a geometric center defined by the planar dipole antennas for passing through a plurality of signal transmission lines, and matching the feeding end and the ground end of each planar dipole antenna with The connecting lines of the geometric centers defined by the planar dipole antennas are perpendicular to the extending direction of the shorting sections, so that when the signal transmission lines are electrically connected to the planar dipole antenna through the perforations, the extending direction of the signal transmission lines and the planar dipole antennas The extension direction of the short-circuited sections is perpendicular to each other (orthogonal) to avoid the problem that the signal transmission line is pressed to the planar dipole antenna and the antenna signal interferes with the system circuit.

Preferably, the area of the antenna substrate is less than or equal to the area of the system module to ensure that the system module can completely reflect the radiation of each planar dipole antenna.

The invention provides an electronic device with a multi-antenna system, comprising a casing, an antenna module and a system module. The antenna module is assembled in the casing and comprises an antenna substrate and a plurality of planar dipole antennas. The antenna substrate includes a first surface and a second surface opposite to the first surface; the planar dipole antennas are disposed on the first surface of the antenna substrate, and each of the planar dipole antennas includes a short circuit segment having a ground end And providing a first radiating arm of a first operating frequency band, and a second radiating arm for providing a second operating frequency band, wherein the first radiating arms are respectively connected to two ends of the short-circuiting section, and the second radiating beams The arms respectively have a feeding section connected to the short-circuiting section, and an extending section extending from the end of the feeding section, one of the second radiating arms has a feeding end, and the feeding of each of the planar dipole antennas The geometric center defined by the end and the ground and the planar dipole antennas are in the same straight line, and the geometric center of each of the planar dipole antennas is the same as the geometric center defined by the planar dipole antennas, and The shortest distance between adjacent planar dipole antennas is the same; the system module is assembled in the housing, and includes at least one ground plane facing the second surface of the antenna substrate, and the second surface of the system module and the antenna substrate The parallel phases are separated by a distance for reflecting the radiation of the planar dipole antennas.

One of the effects of the present invention is that a plurality of planar dipole antennas are disposed on the antenna substrate to receive or transmit signals of different frequency bands, and the radiation of the planar dipole antenna is reflected through at least one ground plane on the system module. The radiation pattern of the antenna module can be characterized by high directivity and high antenna gain, which can improve communication coverage and transmission distance.

The second effect of the present invention is that the geometric center of each planar dipole antenna in the multi-antenna system has the same distance from the geometric center defined by the planar dipole antennas, and the shortest distance of any two adjacent planar dipole antennas is the same. , so that each planar dipole antenna has the same isolation and the same radiation field and signal coverage.

The third effect of the present invention is that the planar dipole antenna is fabricated using a printed circuit board, is simple to manufacture and low in cost, and has a low-profile appearance and a planar structure, which is very suitable for application. On a small outdoor wireless network bridge.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to FIG. 1, a preferred embodiment of a multi-antenna system 100 of the present invention is a 2-dimensional planar (2-D planer) pair operable in a dual-band wireless local area network WLAN (2400-2484/5150-5350 MHz). A dual-band multi-antenna system 100, and the 2-dimensional planar dual-frequency dipole antenna can be fabricated on a printed circuit board, and the dual-frequency dipole antenna design is printed on the same side of the printed circuit board. In this way, the design can greatly reduce the cost. In the present embodiment, the multi-antenna system 100 includes an antenna module 10 and a system module 20 disposed in parallel with the antenna module 10.

The antenna module 10 includes an antenna substrate 1 and a plurality of planar dipole antennas 2. The antenna substrate 1 (or dielectric substrate) may be circular or arbitrary polygonal shape and made of an insulating material (for example, glass fiber, FR4). The antenna substrate 1 has a first surface 11 , a second surface 12 opposite to the first surface 11 , and a through hole 13 through which a plurality of signal transmission lines 6 pass.

Referring to FIG. 2, in the embodiment, the planar dipole antenna 2 is a half-wavelength dual-frequency dipole antenna, and the number thereof is three, but the number and type of antennas are not limited thereto. The planar dipole antennas 2 are disposed on the first surface 11 of the antenna substrate 1, and each of the planar dipole antennas 2 includes a shorting section 3 and a first radiating arm 4 that provides a first operating frequency band. And a second radiating arm 5 for providing a second operating frequency band. Wherein, the length of the first radiating arm 4 is longer than that of the second radiating arm 5. In the embodiment, the first operating band of the first radiating arm 4 is a low frequency of 2.4 GHz, and the second operating band of the second radiating arm 5 is High frequency 5 GHz.

The short-circuiting section 3 has a ground point 31; the two first radiating arms 4 are respectively connected to opposite ends of the short-circuiting section 3 and extend in a direction parallel to the extending direction of the short-circuiting section 3 (ie, the Y-axis direction); The second radiating arm 5 has a feeding section 51 connected to the short-circuiting section 3, and an extending section 52 connected to the end of the feeding section 51 and extending parallel to the extending direction of the short-circuiting section 3 (ie, the Y-axis direction), A feeding arm 51 and a second radiating arm 5 share the feeding section 51. A first feed gap 32 is spaced between the two feed segments 51. There is a feed point 53 on one of the two feed sections 51, the feed end 53 is opposite to the ground end 31 and spaced apart by a second feed gap 33, and the first feed gap 32 is The second feed gap 33 is in communication.

By arranging a plurality of planar dipole antennas 2 on the antenna substrate 1 to receive or transmit signals of a plurality of different frequency bands, and adjusting the second feeding gap 33 and the short-circuiting section 3 of the planar dipole antenna 2, the reactance is improved. Value, which balances both capacitive and inductive reactance to achieve good impedance bandwidth of the antenna, and excellent impedance matching in the 2.4/5 GHz wireless local area network band (10-dB return loss definition) Or 2:1-VSWR).

In this embodiment, the width of the extension 52 of the second radiating arm 5 away from the end of the feeding feed section 51 is greater than the width of the end adjacent to the feeding section 51, so that the extension 52 is approximately trapezoidal in exchange for a larger The operating frequency band, but the shape of the extending portion 52 is not limited to the embodiment, and may be a rectangle, a trapezoid as shown in FIG. 3, or an isosceles triangle (bow tie) or a teardrop shape as shown in FIG. . In addition, referring to FIG. 5, the feeding end 53 may also be located on the other feeding section 51 as long as the second feeding gap 33 and the grounding end 31 are translated relative to the feeding end 53, so that the feeding end 53 and the grounding end 31 are provided. The geometric centers defined by the three planar dipole antennas 2 can be located on the same line (please refer to FIG. 6 at the same time).

It is worth mentioning that the short-circuit section 3 of the planar dipole antenna 2 in FIG. 2 protrudes from the first radiation arm 4 in the X-axis direction, and the one side of the short-circuit section 3 in FIG. 3 to FIG. The one side of the first radiating arm 4 is on the same straight line, and the difference between the two embodiments is only that the two first radiating arms 4 in FIGS. 3 to 5 are elongated in length (up to the resonance wavelength 1/2 λ). However, both good impedance bandwidth and excellent impedance matching in the 2.4/5 GHz wireless local area network band can be achieved, and are not limited to this embodiment.

Referring to FIG. 6, the number of planar dipole antennas 2 of the present embodiment is three, and the planar dipole antennas 2 are symmetrically distributed along the circumference of the circular antenna substrate 1, so that the geometric center of each planar dipole antenna 2 is The geometric center (ie, point A) defined by the three planar dipole antennas 2 has the same distance, that is, La=Lb=Lc, and the shortest distance between any two adjacent planar dipole antennas 2 is the same, that is, L1=L2=L3, the geometrical center of any two adjacent planar dipole antennas 2 is also the same as the angle between the geometric center defined by the three planar dipole antennas 2 (ie, point A) That is, α = β = γ, that is, the angle of 120 is clamped. Such a symmetrical structure antenna can prevent mutual coupling between the planar dipole antennas 2, so that they maintain the same isolation, and each planar dipole antenna 2 is in space. Has a more symmetrical and equal signal coverage.

Referring to FIG. 1, FIG. 2 and FIG. 6, in particular, the perforations 13 of the antenna substrate 1 are located at geometric centers defined by the three planar dipole antennas 2, and the feeding in each of the planar dipole antennas 2 The geometric center defined by the terminal 53 and the grounding terminal 31 and the three planar dipole antennas 2 are on the same straight line (as shown in FIG. 6), and the straight line is perpendicular to the extending direction of the short-circuited section. Thus, when the signal transmission line 6 is electrically connected to the feeding end 53 of the planar dipole antenna 2 and the grounding end 31, the antenna signals received by the planar dipole antennas 2 are transmitted to the wireless broadband router or hub through the through holes 13. When the circuit board (not shown) in the (hub), the extending direction of the signal transmission line 6 is perpendicular to the extending direction of the short-circuiting section 3 of the planar dipole antenna 2 (ie, the Y-axis direction) (to be orthogonal) to avoid The problem that the signal transmission line 6 is pressed to the first radiating arm 4 and the second radiating arm 5 of the planar dipole antenna 2 causes interference between the antenna signal and the system circuit.

The system module 20 is a system circuit board that can be circular or of any polygonal shape. The system module 20 has at least one ground plane 201 (for example, a metal surface) facing the second surface 12 of the antenna substrate 1. The ground plane 201 can be regarded as a system ground plane as a system ground plane on the system board. A reflector for reflecting the radiation of the planar dipole antenna 2, thereby not only providing the antenna module 10 with high directivity, but also lifting the antenna module 10 in a single direction (ie, the antenna substrate 1) Antenna gain of the first surface 11 of the normal direction). The system module 20 can be a multi-layer structure, the uppermost layer is a thin metal layer, the lower layer is a dielectric substrate, or can be a circuit layer containing more layers. Moreover, a gap exists between the ground plane (which can be used as a reflective surface) 201 and the second surface 12, and is used as an effective space for electronic components (not shown) on the system module 20. In addition, the area of the antenna substrate 1 of the present embodiment is less than or equal to the area of the system module 20 to ensure that the system module 20 can completely reflect the radiation of each planar dipole antenna 2.

In addition, referring to FIG. 7, the multi-antenna system 100 of the present embodiment is installed in a housing 210 of an electronic device 200 such as an outdoor wireless access point (AP), and is connected by a small coaxial line ( As a signal transmission line 6, the mini-coaxial cable feeds the signal to the feeding end 53 of the planar dipole antenna 2, so that the multi-antenna system 100 can be matched with the system module 20 (ie, the system board) of different applications to improve the multi-antenna system. 100 uses the elasticity. Of course, the type of the signal transmission line 6 is not limited by this embodiment.

8 to FIG. 10 are schematic diagrams showing actual dimensions of the multi-antenna system 100 of the present embodiment, wherein FIG. 8 is a plan view of the multi-antenna system 100; FIG. 9 is a planar development view of the single-plane dipole antenna 2; The side view between the module 10 and the system module 20, the unit of the number in each figure is mm (mm), can refer to the data in the figure to know the actual size of the embodiment, but not the implementation The example is limited.

Referring to FIG. 8 and FIG. 10, the total area of the planar dipole antenna 2 of the present embodiment is 13.5×36.5 mm ² , and the first radiator 4 and the second radiator 5 can respectively resonate with the frequency bands of 2.4 GHz and 5 GHz. In addition, the distance between the antenna substrate 1 and the system module 20 is between 5 and 10 mm, so that the multi-antenna system 100 has a low-profile stacked form, and can provide more kinds of electronic components to be placed in the system mode. On the group 20, the internal space configuration of the entire electronic device 200 (Fig. 7) can be effectively utilized, and a distance of 10 mm (mm) between the embodiments will obtain a better antenna gain, and the extension 52 and the first radiation arm The distance between 4 is preferably between 0.5 and 1.5 mm. In particular, the thickness of the planar dipole antenna 2 and the thickness of the metal on the system module 20 (about 0.035 mm) are much smaller than the thickness of the antenna substrate 1 and the system module 20, and therefore are not shown in FIG.

Referring to FIG. 11, the reflection coefficient of each planar dipole antenna 2 is measured. For convenience of description, referring to FIG. 6, the three planar dipole antennas 2 are respectively defined as a first planar dipole. The antenna 21, a second planar dipole antenna 22 and a third planar dipole antenna 23 are provided. While in FIG. _11, S 11, S ₂₂ and S ₃₃ are a first planar dipole antenna 21, a second planar dipole antenna 22 and the third plane 23 of the dipole antenna reflection coefficient. It can be known from experiments that the center frequency of the first operating band provided by the first radiator 4 is 2.4 GHz, and the center frequency of the second operating band provided by the second radiator 5 is 5 GHz, and the two are respectively at 2.4 GHz and 5 GHz. The reflection coefficient is less than minus 10-dB, which conforms to the specifications of the 2.4 GHz and 5 GHz wireless local area network bands, so this embodiment is indeed applicable to the wireless local area network.

See FIG. 12 for isolation between two respective planar dipole antenna (Isolation) FIG measured data, where S is the ₂₁ isolation between the dipole antenna 21 and the second plane 22 a first planar dipole antenna; S ₃₁ is the isolation between the first planar dipole antenna 21 and the third planar dipole antenna 23; S ₃₂ is the isolation between the second planar dipole antenna 22 and the third planar dipole antenna 23. It can be known from experiments that the isolation between the planar dipole antennas 2 is lower than minus 20-dB and minus 30-dB in the 2.4 GHz and 5 GHz bands, respectively, and has good isolation.

Referring to FIG. 13 and FIG. 14, FIG. 13 is a 3-D radiation pattern diagram of the multi-antenna system 100 operating at frequencies of 2400 MHz, 2442 MHz, and 2484 MHz; and FIG. 14 is a multi-antenna system 100 operating at frequencies of 5150 MHz, 5490 MHz, and 5825 MHz. -D radiation field pattern. As can be seen from FIG. 13 and FIG. 14 , the multi-antenna system 100 has a high antenna gain in the positive Z-axis direction by the mutual cooperation of the antenna module 10 and the system module 20, that is, a high directivity, which is applicable to wireless. Network Bridge (AP).

15 is a radiation efficiency/antenna gain-frequency graph of the multi-antenna system 100 of the present embodiment. As can be seen from the figure, the maximum gain of the antenna in the 2.4 GHz and 5 GHz bands is above 6 dBi, which has the characteristics of high antenna gain. The radiation efficiency of the antenna is also above 60%, which is a good printed antenna efficiency.

Referring to FIG. 1, in particular, the multi-antenna system 100 of the present embodiment reflects the radiation of the planar dipole antenna 2 by the system module 20, without the need for an additional 3-D stereo structure metal piece antenna design. By connecting an antenna ground plane, the antenna radiation field type has high directivity, and the multi-antenna system 100 operates in the 2.4G and 5GHz frequency bands, and the half-power bandwidth (HPBW) can be as high as 99. ° and 106°, and with a good front-to-back ratio of polarization components, up to 20 dB in the band to achieve high gain antenna design.

In summary, the power of the multi-antenna system 100 of the present invention is as follows:

1. By arranging a plurality of planar dipole antennas 2 on the antenna substrate 1, to receive or transmit signals of a plurality of different frequency bands, and to adjust the second feeding gap 33 and the short-circuiting section 3 of the planar dipole antenna 2, The reactance value can be improved, and the capacitive and inductive properties of the planar dipole antenna 2 can be balanced to achieve a good impedance bandwidth of the antenna, and excellent impedance matching is obtained in the 2.4/5 GHz wireless local area network band.

2. The geometric center of each planar dipole antenna 2 in the multi-antenna system 100 is the same as the geometric center defined by the planar dipole antennas 2, and the shortest distance of any two adjacent planar dipole antennas 2 is the same, The same planar isolation and the same radiation field and signal coverage are provided between the respective planar dipole antennas 2. The geometrical center defined by the feeding end 53 of each planar dipole antenna 2 and the grounding end 31 and the three planar dipole antennas 2 are on the same straight line, so that the signal transmission line 6 is electrically connected to the planar dipole antenna 2 The extending direction of the signal transmission line 6 is perpendicular to the extending direction of the short-circuiting section 3 of the planar dipole antenna 2 (orthogonal), so that the length of the signal transmission line 6 can be minimized, and the signal transmission line 6 can be prevented from being pressed to the plane coupling. The pole antenna 2 causes the antenna signal to interfere with the system circuit. The antenna module 10 is integrated with the system module 20, and the radiation of the planar dipole antenna 2 is reflected by at least one ground plane on the system module 20, so that the antenna module 10 can have high directivity. The antenna gain of the antenna module 10 in a single direction (positive Z-axis direction) can be improved, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

100. . . Multi-antenna system

200. . . Electronic device

210. . . case

10. . . Antenna module

1. . . Antenna substrate

11. . . First surface

12. . . Second surface

13. . . perforation

2. . . Planar dipole antenna

twenty one. . . First planar dipole antenna

twenty two. . . Second planar dipole antenna

twenty three. . . Third planar dipole antenna

3. . . Short circuit segment

31. . . Ground terminal

32. . . First feed gap

33. . . Second feed gap

4. . . First radiation arm

5. . . Second radiation arm

51. . . Feeding segment

52. . . Extension

53. . . Feed end

6. . . Signal transmission line

20. . . System module

201. . . Ground plane

Figure 1 is a diagram showing a preferred embodiment of the multi-antenna system of the present invention;

Figure 2 is a plan development view showing a single planar dipole antenna in the embodiment;

Figure 3 is a view showing another variation of the single planar dipole antenna in this embodiment;

4 is a view showing another variation of the single planar dipole antenna in the embodiment;

Figure 5 is a view showing another variation of the single planar dipole antenna in this embodiment;

Figure 6 is a plan development view showing the multi-antenna system in the embodiment;

Figure 7 is an illustration of an electronic device of a built-in multi-antenna system;

Figure 8 is a view showing the actual size of the dimensions between the respective planar dipole antennas in this embodiment;

Figure 9 is a view showing the actual size of a single planar dipole antenna in this embodiment;

Figure 10 is a diagram showing the actual size of the antenna module and the system module in the embodiment;

11 is a view showing measurement data of reflection coefficient of each planar dipole antenna in the embodiment;

Figure 12 is a diagram showing the isolation measurement data of each of the planar dipole antennas in the present embodiment;

Figure 13 is a diagram showing the 3-D radiation pattern of the multi-antenna system of the present embodiment at frequencies of 2400 MHz, 2442 MHz, and 2484 MHz, respectively;

14 is a diagram showing a 3-D radiation pattern of the multi-antenna system of the present embodiment at frequencies of 5150 MHz, 5490 MHz, and 5825 MHz, respectively;

Figure 15 is a graph showing the radiation efficiency / antenna gain-frequency of the multi-antenna system of the present embodiment.

100. . . Multi-antenna system

10. . . Antenna module

1. . . Antenna substrate

11. . . First surface

12. . . Second surface

13. . . perforation

2. . . Planar dipole antenna

6. . . Signal transmission line

20. . . System module

201. . . Ground plane

Claims (10)

A multi-antenna system includes: an antenna module, comprising: an antenna substrate including a first surface and a second surface opposite to the first surface; and a plurality of planar dipole antennas disposed on the antenna substrate Each of the planar dipole antennas includes a shorting section having a grounding end, a first radiating arm that provides a first operating frequency band, and a second radiating arm that provides a second operating frequency band. The first radiating arms are respectively connected to two ends of the short-circuiting section, and the second radiating arms respectively have a feeding section connected to the short-circuiting section, and an extending section extending from an end of the feeding section, One of the second radiating arms has a feeding end, and the feeding end and the grounding end of each of the planar dipole antennas are in the same straight line with the geometric center defined by the planar dipole antennas, and the planar dipoles The geometric center of the antenna is the same as the geometric center defined by the planar dipole antennas, and the shortest distance between any two adjacent planar dipole antennas is the same; and a system module including at least one facing the day The ground plane of the second surface of the substrate, and the system module in parallel with the second surface of the antenna substrate are spaced apart a distance to the plane of these radiation-reflecting dipole antenna. According to the multi-antenna system of claim 1, wherein the two first radiating arms of each of the planar dipole antennas are respectively connected to both ends of the short-circuiting section and extend away from the extending direction of the short-circuiting section. And the second radiating arms respectively have a feeding section connected to the short-circuiting section, and an extending section connected to the end of the feeding section and extending parallel to the extending direction of the short-circuiting section, the feeding end is located at the feeding section Enter one of the segments. The multi-antenna system of claim 2, wherein the feeding end of the planar dipole antenna and the grounding end and the geometric center of the planar dipole antenna are perpendicular to the short-circuited section. The direction of extension. The multi-antenna system according to claim 3, wherein the geometric center of any two adjacent planar dipole antennas is the same as the angle between the geometric centers respectively defined by the plane dipole antennas . The multi-antenna system according to claim 4, wherein the number of the planar dipole antennas is three, and the geometric centers of any two adjacent planar dipole antennas are respectively defined by the planar dipole antennas. The line between the geometric centers is at an angle of 120 degrees. The multi-antenna system of claim 4, wherein the two feed-in sections of the planar dipole antenna are separated by a first feed gap, and the feed end is spaced apart from the ground end by a second Feeding the gap, the first feed gap is in communication with the second feed gap. The multi-antenna system of claim 6, wherein a width of each of the extensions away from an end connecting the feed section is greater than a width of an end adjacent to the feed section. The multi-antenna system of claim 7, wherein the antenna substrate further comprises a perforation at a geometric center defined by the planar dipole antennas for passage of a plurality of signal transmission lines. The multi-antenna system of claim 1, wherein the area of the antenna substrate is less than or equal to the area of the system module. An electronic device having a multi-antenna system includes: a housing; an antenna module mounted in the housing, the antenna module comprising: an antenna substrate, including a first surface and a first surface opposite to the first a second surface of the surface; and a plurality of planar dipole antennas disposed on the first surface of the antenna substrate, each of the planar dipole antennas including a shorting section having a grounding end and two providing a first operating frequency band a first radiating arm, and a second radiating arm for providing a second operating frequency band, wherein the first radiating arms are respectively connected to two ends of the short-circuiting section, and the second radiating arms respectively have a connection to the short-circuiting section a feeding section, and an extension extending from an end of the feeding section, one of the second radiating arms having a feeding end, a feeding end, a grounding end of the planar dipole antenna, and the like The geometric centers defined by the planar dipole antennas are located on the same straight line, and the geometric center of each of the planar dipole antennas is the same as the geometric center defined by the planar dipole antennas, and between two adjacent planar dipole antennas Shortest And the system module is disposed in the housing, the system module includes at least one grounding surface facing the second surface of the antenna substrate, and the system module and the antenna substrate The two surfaces are spaced apart by a distance to reflect the radiation of the planar dipole antennas.