TWI493792B - Multiband antenna - Google Patents

Description

Multi-frequency antenna

The present invention relates to a multi-frequency antenna, and more particularly to a multi-frequency antenna that can cover eight frequency bands of WWAN/LTE (Wireless Wide Area Network, WWAN/Long Term Evolution, LTE).

Due to the rapid development of wireless communication, a variety of communication products are constantly being introduced. In order to pursue faster downloading of data on the Internet, the 3GPP (3GPP) organization has developed a next-generation 4G communication system, the so-called Long Term Evolution (LTE) mobile communication technology. At present, the LTE communication system is gradually commercialized, and with the increase of the communication frequency band, the operating frequency band that the antenna must cover must also be increased. For antennas operating on WWAN/LTE700/2500/2600, the low frequency band must cover 698 MHz to 960 MHz, and the high frequency band must cover 1710 MHz to 2690 MHz. As current mobile devices (eg, mobile phones, tablets) are headed towards thinner and lighter, the antennas must be designed in a limited space and must be able to inspire sufficient operating bandwidth. The above requirements are a big challenge for designers.

The present invention provides a multi-band antenna, including: a substrate having a first surface and a second surface opposite to the first surface; a ground plane disposed on the second surface a feed portion disposed on the first surface and having a feed point; a first radiation branch disposed on the first surface and extending in a first direction and coupled to the connection a second radiation branch disposed on the first surface and extending in a second direction relative to the first direction and coupled to the first radiation branch; and a parasitic radiation member disposed On the first surface, and coupled to the ground plane, wherein the first radiation branch at least partially surrounds the feed portion, and the second radiation branch at least partially surrounds the parasitic radiation member .

The multi-frequency antenna of the present invention can cover eight frequency bands of LTE700/GSM850/900 and GSM1800/1900/UMTS/LTE2300/2500.

Fig. 1A is a perspective view showing a multi-frequency antenna 100 according to an embodiment of the present invention. FIG. 1B is a plan view showing a multi-frequency antenna 100 according to an embodiment of the present invention. As shown in FIG. 1A, the multi-frequency antenna 100 includes a substrate 110, a ground plane 120, a feeding portion 130, radiation branches 140, 150, and a parasitic radiation member 160. The substrate 110 has two different surfaces E1, E2, wherein the surface E1 is opposite to the surface E2. The ground plane 120, the feed portion 130, the radiation branches 140, 150, and the parasitic radiating element 160 are all made of metal, such as copper or silver. The ground plane 120 is disposed on the surface E2. The feeding portion 130 is disposed on the surface E1 and has a feeding point PF. The feed point PF can be electrically coupled to a signal source SS and used to receive the feed signal from the signal source SS. The radiation branch 140 is disposed on the surface E1 and extends in the first direction -X and is electrically coupled to the ground plane 120. The radiation branch 150 is disposed on the surface E1 and extends to the second direction +X with respect to the first direction -X and is electrically coupled to the radiation branch 140. The parasitic radiation member 160 is disposed on the surface E1 and electrically coupled to the ground plane 120. In an embodiment of the present invention, a short-circuit point P1 of the radiating branch 140 is electrically coupled to the ground plane 120 via the metal line VA1, and a short-circuit point P2 of the parasitic radiating element 160 is electrically coupled via the metal line VA2. Go to ground plane 120. In a preferred embodiment of the invention, the radiating branch 140 at least partially surrounds the feed portion 130, and the radiating branch 150 at least partially surrounds the parasitic radiating member 160.

As shown in FIG. 1B, in an embodiment of the invention, the radiation branch 140 can include a U-shaped member 141 and an I-shaped member 142. One end of the I-shaped member 142 is electrically coupled to the U-shaped member 141 and the radiation branch 150, and the other end of the I-shaped member 142 (ie, the short-circuit point P1) is electrically coupled to the ground plane 120. In a preferred embodiment of the invention, the feed portion 130 is generally L-shaped, the radiation branch 150 is generally U-shaped, and the parasitic radiation member 160 is generally L-shaped. Additionally, in order to be able to alternately couple to form a loop antenna, the shortest distance between the feed portion 130 and the radiating branch 140 (i.e., the distance D1) must be less than or equal to 0.5 mm. In an embodiment of the invention, the distance D1 may be equal to 0.4 mm. The substrate 110 may be an FR4 plate having a dielectric constant of about 4.3, and the substrate 110 may have a thickness of 0.8 mm.

2A is a perspective view showing a multi-frequency antenna 200 according to another embodiment of the present invention. 2B is a plan view showing a multi-frequency antenna 200 according to another embodiment of the present invention. As shown in FIG. 2A, the multi-frequency antenna 200 includes a substrate 110, a ground plane 120, a feed portion 230, radiation branches 240, 250, and a parasitic radiation member 260. The substrate 110 has two different surfaces E1, E2, wherein the surface E1 is opposite to the surface E2. The ground plane 120, the feed portion 230, the radiation branches 240, 250, and the parasitic radiation member 260 are all made of metal, such as copper or silver. The feeding portion 230 is disposed on the surface E1 and has a feeding point PF. The radiation branch 240 is disposed on the surface E1 and extends in the first direction -X and is electrically coupled to the ground plane 120. The radiation branch 250 is disposed on the surface E1 and extends to the second direction +X with respect to the first direction -X and is electrically coupled to the radiation branch 240. The parasitic radiation member 260 is disposed on the surface E1 and electrically coupled to the ground plane 120. In an embodiment of the present invention, a short-circuit point P1 of the radiating branch 240 is electrically coupled to the ground plane 120 via the metal line VA1, and a short-circuit point P2 of the parasitic radiating element 260 is electrically coupled via the metal line VA2. Go to ground plane 120. In a preferred embodiment of the invention, the radiating branch 240 at least partially surrounds the feed portion 230, and the radiating branch 250 at least partially surrounds the parasitic radiating member 260.

As shown in FIG. 2B, in an embodiment of the invention, the radiation branch 240 can include a U-shaped member 241 and an L-shaped member 242. In order to save design space, the multi-frequency antenna 200 uses an L-shaped member 242 instead of an I-shaped member to increase the length of the radiating branch 240. One end of the L-shaped member 242 is electrically coupled to the U-shaped member 241 and the radiation branch 250, and the other end of the L-shaped member 242 (ie, the short-circuit point P1) is electrically coupled to the ground plane 120. In a preferred embodiment of the invention, the feed portion 230 is generally L-shaped, the radiation branch 250 is generally U-shaped, and the parasitic radiating member 260 is generally L-shaped. Similarly, in order to be able to alternately couple to form a loop antenna, the shortest distance between the feed portion 230 and the radiating branch 240 (i.e., the distance D1) must be less than or equal to 0.5 mm. In an embodiment of the invention, the distance D1 may be equal to 0.4 mm. The substrate 110 may be an FR4 plate having a dielectric constant of about 4.3, and the substrate 110 may have a thickness of 0.8 mm.

In terms of component size, the total length of the feed metal portion is about 27 mm; the total length of the radiation branch 240 is about 80 mm; the total length of the radiation branch 250 is about 68 mm; and the total length of the parasitic radiating member 260 is about 20 mm; The ground plane 120 has a length of approximately 180 mm and a width of approximately 110 mm. The antenna body portion (excluding the ground plane 120 and a portion of the substrate 110 on the ground plane 120) has a length of about 75 mm, a width of about 14 mm, and a height of about 0.8 mm. It is worth noting that the above component sizes are only examples, and the user can freely adjust all component sizes according to the required frequency band.

Figure 3 is a diagram showing the Return Loss of the multi-frequency antenna 100 according to an embodiment of the present invention, wherein the horizontal axis represents the operating frequency (unit: MHz) and the vertical axis represents the foldback loss (unit: dB). . When the feed signal is entered by the feed point PF, the multi-frequency antenna 100 can be excited to generate the frequency bands FB1, FB2. The feed portion 130, the radiation branch 140, and the radiation branch 150 are collectively excited to generate a low frequency band FB1. In addition, the feeding portion 130, the radiation branch 140, and the parasitic radiation member 160 are collectively excited to generate a high frequency band FB2. In a preferred embodiment of the invention, the frequency band FB1 is between about 700 MHz and 960 MHz, and the frequency band FB2 is between about 1710 MHz and 2690 MHz. The fold loss map of the multi-frequency antenna 200 is very similar to that of the multi-frequency antenna 100, and the frequency bands covered are also the same, and the description will not be repeated here. It should be noted that the user can also adjust the operating band of the antenna by changing the component length, the substrate thickness or (and) the dielectric constant, and is not limited to the above-mentioned band range.

4A and 4B are graphs showing the Radiation Efficiency of the multi-frequency antenna 200 according to an embodiment of the present invention, wherein the horizontal axis represents the operating frequency (unit: MHz) and the vertical axis represents the percentage of the radiation efficiency. As shown in FIG. 4A, the multi-frequency antenna 200 has a radiation efficiency of about 40% to 68% in a low frequency band (ie, three frequency bands such as LTE700/GSM850/900). As shown in FIG. 4B, the multi-frequency antenna 200 has a radiation efficiency of about 40% to 80% in a high frequency band (ie, five frequency bands such as GSM1800/1900/UMTS/LTE2300/2500). The above radiation efficiency can already meet the needs of general mobile devices. The radiation efficiency map of the multi-frequency antenna 100 is similar to that of the multi-frequency antenna 200, and the description thereof will not be repeated here.

The antenna provided by the invention can cover 8 frequency bands of LTE700/GSM850/900 and GSM1800/1900/UMTS/LTE2300/2500, and has a small size and can be applied to mobile devices with communication functions, such as mobile phones and tablet computers. In addition, the antenna of the present invention may be disposed on a Flexible Printed Circuit Board (FPBC) or in a Laser Direct Structuring (LDS) technology.

The present invention has been described above with reference to the preferred embodiments thereof, and is not intended to limit the scope of the present invention, and the invention may be modified and modified without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

100, 200. . . Multi-frequency antenna

110. . . Substrate

120. . . Ground plane

130, 230. . . Feeding department

140, 150, 240, 250. . . Radiation branch

141, 241. . . U-shaped piece

142. . . I-shaped piece

160, 260. . . Parasitic radiation

242. . . L-shaped piece

D1. . . distance

E1, E2. . . surface

P1, P2. . . Short circuit point

PF. . . Feeding point

VA1, VA2. . . metal wires

SS. . . signal source

-X. . . First direction

+X. . . Second direction

1A is a perspective view showing a multi-frequency antenna according to an embodiment of the invention;

1B is a plan view showing a multi-frequency antenna according to an embodiment of the invention;

2A is a perspective view showing a multi-frequency antenna according to another embodiment of the present invention;

2B is a plan view showing a multi-frequency antenna according to another embodiment of the present invention;

3 is a diagram showing a return loss of an antenna according to an embodiment of the invention;

4A is a diagram showing radiation efficiency of a multi-frequency antenna according to an embodiment of the invention;

Figure 4B is a graph showing the radiation efficiency of a multi-frequency antenna according to an embodiment of the present invention.

100. . . Multi-frequency antenna

110. . . Substrate

120. . . Ground plane

130. . . Feeding department

140, 150. . . Radiation branch

160. . . Parasitic radiation

D1. . . distance

E1, E2. . . surface

P1, P2. . . Short circuit point

PF. . . Feeding point

VA1, VA2. . . metal wires

SS. . . signal source

-X. . . First direction

+X. . . Second direction

Claims (9)

A multi-frequency antenna comprising: a substrate having a first surface and a second surface opposite to the first surface; a ground plane disposed on the second surface; a feed portion disposed on the first surface And having a feed point; a first radiation branch disposed on the first surface and extending in a first direction and coupled to the ground plane; a second radiation branch disposed on the first radiation branch a first surface extending in a second direction relative to the first direction and coupled to the first radiation branch; and a parasitic radiation member disposed on the first surface and coupled to the first surface a grounding surface; wherein the first radiation branch at least partially surrounds the feed portion, and the second radiation branch at least partially surrounds the parasitic radiation member; wherein the feed portion is substantially L-shaped, And the feeding portion couples the first radiation branch below it. The multi-frequency antenna of claim 1, wherein the first radiation branch comprises: a U-shaped member; and an I-shaped member coupled to the U-shaped member and coupled to the ground plane. The multi-frequency antenna of claim 1, wherein the first radiation branch comprises: a U-shaped member; and an L-shaped member coupled to the U-shaped member and coupled to the ground plane. The multi-frequency antenna of claim 1, wherein the second radiation branch is substantially U-shaped. The multi-frequency antenna of claim 1, wherein the parasitic radiation member is substantially L-shaped. The multi-frequency antenna of claim 1, wherein the feed portion, the first radiation branch, and the second radiation branch are jointly excited to generate a first frequency band, and the first frequency band is approximately Between 700MHz and 960MHz. The multi-frequency antenna according to claim 1, wherein the feeding portion, the first radiation branch, and the parasitic radiation member are jointly excited to generate a second frequency band, and the second frequency band is about 1710 MHz and Between 2690MHz. The multi-frequency antenna of claim 1, wherein the shortest distance between the feed portion and the first radiation branch is less than or equal to 0.5 mm. The multi-frequency antenna of claim 1, wherein the substrate has a thickness of 0.8 mm.