TWI531120B - Multi-antenna structure - Google Patents

Description

Multi-antenna structure

The invention relates to an antenna, in particular to a multi-antenna structure with multi-input multi-output (MIMO).

In the continuous advancement of technology, in order to improve communication quality and speed, the use of two LTE (Long Term Evolution)/WWAN MIMO antennas is a technology trend, but the isolation and correlation of dual antennas at low frequencies are usually Less desirable, because the radiation pattern in the low frequency band tends to be close to omnidirectional, resulting in a significant increase in transmission rate.

At present, the main reason for the poor isolation of the dual antenna at low frequencies is that the dual antenna structure (as shown in the first figure) includes a substrate 10, a first antenna 20 and a second antenna 30. The substrate 10 has a grounded metal surface 101 on the surface thereof. The grounded metal surface 101 has two short sides 102 and two long sides 103. The first antenna 20 is disposed on the short side 102 of the first antenna 20, and the second antenna 30 is disposed on the other short side 102. When the dual antenna structure is in use, since the current path of the two short sides 102 of the grounded metal surface 101 is shorter than the two long sides 103, the longitudinal current in the low frequency band is stronger than the lateral current, causing the first antenna 20 and the The current of the second antenna 30 is more likely to cause interference, so that the isolation of the low frequency is poor.

Moreover, the first curve 40 and the second curve 50 are disclosed in the isolation analysis graph (shown in the second figure) from the first antenna 20 and the second antenna 30. The second curve 50 has a high frequency band isolation 501 and a low frequency band isolation 502. Since the current path of the two short sides 102 of the grounded metal surface 101 is shorter than the two long sides 103, the longitudinal current in the low frequency band is stronger than the lateral current, and the curve of the low frequency band isolation 502 of the second curve 50 at this time is -6db. Therefore, the low frequency band isolation of the dual antenna is poor, and the currents of the first antenna 20 and the second antenna 30 are more likely to cause interference, which may interfere with each other, and the transmission rate cannot be greatly improved.

Therefore, the main object of the present invention is to solve the problem of the existence of the conventional double antenna structure. The present invention adds two metal wires to the two short sides of the grounded metal surface of the substrate, so that the current paths of the two short sides of the grounded metal surface are The two long sides are the same, so that the longitudinal current and the transverse current intensity are consistent, so that the isolation of the two antennas is good, the two currents do not interfere with each other, and the transmission rate is greatly improved.

In order to achieve the above object, the present invention provides a multi-antenna structure, comprising: a substrate having a grounded metal surface having two short sides and two long sides; and a first antenna disposed on the substrate a second antenna is disposed on the substrate and located on the other short side of the grounded metal surface; a first metal line is connected to the short side of the grounded metal surface; a short side of the grounded metal surface is electrically connected; and a second metal line is electrically connected to the other short side of the grounded metal surface; wherein the first metal line and the second metal line Increasing the current path of the short side of the grounded metal surface, so that the longitudinal current of the low frequency is close to the lateral current intensity, so as to reduce the current interference between the first antenna and the second antenna, so that the first antenna and the second antenna The line has good isolation.

The substrate is a printed circuit board having a first signal feed line and a second signal feed line. The two short sides of the substrate are an upper short side and a lower short side, and the two long sides of the substrate are One right long side and one left long side.

The first antenna has a first bracket, the first bracket has a first radiating body composed of a plurality of metal segments, and the first radiating body is electrically coupled to the first signal feeding line, the first signal The feed line is electrically connected to the copper shaft cable.

Wherein the second antenna has a second bracket, the second bracket has a second radiator formed by a plurality of metal segments, and the second radiator is electrically coupled to the second signal feeding body line. The two signal feed lines are electrically connected to the copper shaft cable.

The first metal wire is electrically connected to the upper short side of the grounded metal surface, and is wound around the first bracket of the first antenna or attached to the casing of the mounted electronic device.

Wherein, the sum of the length of the first metal line and the upper short side of the grounded metal surface is between one-half and one-eighth of the wavelength of the center frequency of the low frequency band.

Wherein, the sum of the length of the first metal line and the upper short side of the grounded metal surface is preferably a quarter wavelength of the center frequency of the low frequency band.

The second metal wire is electrically connected to the lower short side of the grounded metal surface, and is wound around the second bracket of the second antenna or attached to the casing of the mounted electronic device.

Wherein, the sum of the length of the second metal line and the lower short side of the grounded metal surface is between one-half and one-eighth of the wavelength of the center frequency of the low frequency band.

Wherein, the sum of the length of the second metal line and the lower short side of the grounded metal surface is preferably a quarter wavelength of the center frequency of the low frequency band.

Conventional knowledge

10‧‧‧Substrate

101‧‧‧Grounded metal surface

102‧‧‧Two short sides

103‧‧‧2 long side

20‧‧‧First antenna

30‧‧‧second antenna

40‧‧‧First curve

50‧‧‧second curve

501‧‧‧High frequency isolation

502‧‧‧Low frequency isolation

This creation

1‧‧‧Substrate

11‧‧‧Grounded metal surface

12‧‧‧Two short sides

12a‧‧‧Upper side

12b‧‧‧lower side

13‧‧‧2 long side

13a‧‧‧Right long side

13b‧‧‧Left long side

14‧‧‧First signal feed line

15‧‧‧Second signal feed line

2‧‧‧first antenna

21‧‧‧First bracket

22‧‧‧First radiator

3‧‧‧second antenna

31‧‧‧second bracket

32‧‧‧Second radiator

4‧‧‧First metal wire

5‧‧‧second metal wire

6‧‧‧First curve

7‧‧‧second curve

71‧‧‧High frequency isolation

72‧‧‧Low frequency isolation

8‧‧‧Electronic devices

81‧‧‧Shell

9‧‧‧ Current path

The first figure is a schematic diagram of a conventional dual antenna structure.

The second figure is a schematic diagram of the isolation analysis curve of the first figure.

The third figure is a perspective view of the appearance of the dual antenna of the present invention.

The fourth figure is a schematic diagram of the dual antenna decomposition of the present invention. As shown in the figure: The fifth figure is a schematic diagram of the current path flow direction of the dual antenna of the present invention.

The sixth figure is a schematic diagram of the isolation analysis curve of the dual antenna of the present invention.

Figure 7 is a schematic view of another embodiment of the present invention.

The technical content and detailed description of the present invention will now be described with reference to the following drawings: Please refer to the third and fourth figures, which are perspective and exploded views of the dual antenna of the present invention. As shown in the figure, the multi-antenna structure of the present invention comprises: a substrate 1, a first antenna 2, a second antenna 3, a first metal line 4 and a second metal line 5.

The substrate 1 has a grounded metal surface 11 thereon, and the grounded metal surface 11 has a short side 12 and two long sides 13 around the ground. The two short sides 12 are an upper short side 12a and a lower short side 12b. The two long sides 13 are a right long side 13a and a left long side 13b. The substrate 1 has a first signal feeding line 14 and a second signal feeding line 15. In the illustration, the substrate 1 is a printed circuit board.

The first antenna 2 is disposed on the substrate 1 at a position close to the upper short side 12a of the grounding metal surface 11 and has a first bracket (first carrier) 21 thereon. The first bracket The first radiator 22 is electrically connected to the first signal feeding line 14 of the substrate 1 , and the first signal feeding line 14 and the copper shaft cable (FIG. Not shown in the electrical connection.

The second antenna 3 is disposed on the substrate 1 at a position close to the lower short side 12b of the grounding metal surface 11 and has a second bracket 31 thereon. The second bracket 31 has a plurality of metals thereon. A second radiator 32 is electrically connected to the second signal feeding line 15. The second signal feeding line 15 is electrically connected to a copper shaft cable (not shown).

The first metal wire 4 is electrically connected to the upper short side 12a of the grounded metal surface 11 and wound around the first bracket 21 of the first antenna 2. In the figure, the sum of the length of the first metal line 4 and the upper short side 12a of the grounded metal surface 11 is one-half to one-eighth of the wavelength of the center frequency of the low frequency band, but at a quarter wavelength For the best.

The second metal wire 5 is electrically connected to the lower short side 12b of the grounded metal surface 11 and wound around the second bracket 31 of the second antenna 3. In the figure, the sum of the length of the second metal line 5 and the lower short side 12b of the grounded metal surface 11 is one-half to one-eighth of the wavelength of the center frequency of the low frequency band, but at a quarter wavelength For the best.

The first metal wire 4 and the second metal wire 5 increase the current path of the upper short side 12a and the lower short side 12b of the ground metal surface 11, and the right long side 13a and the left length of the ground metal surface 11 The current path and intensity of the edge 13b are the same to reduce the mutual interference between the two antennas, so that the low frequency of the dual antenna has good isolation.

Please refer to the fifth figure, which is a schematic diagram of current path flow of the dual antenna of the present invention. As shown in the figure, the first metal wire 4 and the second metal wire 5 are electrically connected to the upper short side 12a and the lower short side 12b of the grounding metal surface 11 of the substrate 1 of the dual antenna to increase the ground. The current path 9 of the upper short side 12a and the lower short side 12b of the metal surface 11 is such that the current path 9 of the upper short side 12a and the lower short side 12b of the grounded metal surface 11 and the right long side 13a of the grounded metal surface 11 and The current path of the left long side 13b is as long as the longitudinal current of the low frequency is close to the lateral current intensity to lower the first antenna 2 The current interference between the second antenna 3 and the first antenna 2 and the second antenna 3 have good isolation.

Please refer to the sixth figure, which is a schematic diagram of the isolation analysis curve of the dual antenna of the present invention. As shown in the figure, a first curve 6 and a second curve 7 appear in the isolation line analysis chart, and the second curve 7 has a high frequency band isolation 71 and a low frequency band isolation 72.

After the first metal wire 4 and the second metal wire 5 of the present invention are electrically connected to the upper short side 12a and the lower short side 12b of the grounded metal surface 11, the upper short side 12a and the lower side of the grounded metal surface 11 are made shorter. The current path of the side 12b is as long as the current path of the right long side 13a and the left long side 13b of the grounded metal surface 11, so that the low frequency longitudinal current is close to the lateral current intensity, and the low frequency isolation of the second curve 7 is 72. The curve is close to -10db or below -10db, which improves the low-frequency isolation of the dual antennas and makes the communication more effective.

Please refer to the seventh figure, which is a schematic view of another embodiment of the present invention. As shown in the figure, after the first metal wire 4 and the second metal wire 5 of the present invention are electrically connected to the upper short side 12a and the lower short side 12b of the grounded metal surface 11 of the substrate 1, the wire can be wound and fixed. In addition to the first bracket 21 of the first antenna 2 and the second bracket 31 of the second antenna 3, the first metal wire 4 and the second metal wire 5 may be attached to the used The housing 81 of the electronic device 8 is on the housing 81.

The above are only the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. That is, the equivalent changes and modifications made by the scope of the patent application of the present invention are covered by the scope of the invention.

1‧‧‧Substrate

11‧‧‧Grounded metal surface

12‧‧‧Two short sides

12a‧‧‧Upper side

12b‧‧‧lower side

13‧‧‧2 long side

13a‧‧‧Right long side

13b‧‧‧Left long side

14‧‧‧First signal feed line

15‧‧‧Second signal feed line

2‧‧‧first antenna

21‧‧‧First bracket

22‧‧‧First radiator

3‧‧‧second antenna

31‧‧‧second bracket

32‧‧‧Second radiator

4‧‧‧First metal wire

5‧‧‧second metal wire

Claims (5)

A multi-antenna structure is electrically connected to a copper shaft cable and mounted in a casing of an electronic device, comprising: a substrate, the substrate is a printed circuit board having a grounded metal surface thereon, the grounded metal surface The substrate has two short sides and two long sides, and the two short sides of the substrate are an upper short side and a lower short side, and the two long sides of the substrate are a right long side and a left long side, and the substrate has a first signal a feed line and a second signal feed line; a first antenna is disposed on the substrate and located on an upper short side of the grounded metal surface, the first antenna has a first bracket, the first bracket a first radiator having a plurality of metal segments, the first radiator being electrically connected to the first signal feed line, the first signal feed line being electrically connected to the copper shaft cable; and a second antenna Is disposed on the substrate and located on a lower short side of the grounded metal surface, the second antenna has a second bracket, and the second bracket has a second radiator composed of a plurality of metal segments, the second The second radiator is electrically connected to the second signal feeding line of the substrate The second signal feeding line is electrically connected to the copper shaft cable; a first metal wire is electrically connected to the upper short side of the grounding metal surface, and is wound on the first bracket of the first antenna Or attached to the housing; and a second metal wire electrically connected to the lower short side of the grounded metal surface, and wound on the second bracket of the second antenna or attached to the shell The first metal wire and the second metal wire increase the current path of the short side of the ground metal surface, so that the low-frequency longitudinal current and the lateral current intensity are close to reduce the first antenna and the second day. The current interference between the lines provides good isolation between the first antenna and the second antenna. The multi-antenna structure of claim 1, wherein the sum of the length of the first metal line and the upper short side of the grounded metal surface is between one-half and one-eighth of the wavelength of the center frequency of the low frequency band. The multi-antenna structure of claim 2, wherein the sum of the length of the first metal line and the upper short side of the grounded metal surface is preferably a quarter wavelength of the center frequency of the low frequency band. The multi-antenna structure of claim 3, wherein the sum of the length of the second metal line and the lower short side of the grounded metal surface is between one-half and one-eighth of the wavelength of the center frequency of the low frequency band. The multi-antenna structure of claim 4, wherein the sum of the length of the second metal line and the lower short side of the grounded metal surface is preferably a quarter wavelength of the center frequency of the low frequency band.