TWI473349B - Stand-alone multi-band antenna - Google Patents

Description

Stand-alone multi-frequency antenna

The present invention relates to an antenna, and more particularly to a stand-alone multi-band antenna.

Traditional built-in antennas are mostly Planar Inverted-F Antenna (PIFA) or monopole antennas. These types of antennas must have corresponding ground planes to excite good impedance. Matching and radiation characteristics. In general, the antenna ground plane is typically the system ground plane within the electronic device that is used to provide routing to circuit components within the electronic device. When the circuit components on the system ground plane are placed at different positions, the size and shape of the system ground plane will be different. In other words, the impedance and radiation characteristics of the antenna will change correspondingly with different system ground planes.

For the antenna designer, in addition to designing the antenna pattern, it is necessary to take into account factors such as the size and shape of the system ground plane, and thus increase the design complexity of the antenna. From the recent antenna development overview, it can be found that the stand-alone antenna is gradually being used in electronic devices for network communication. The advantage of the stand-alone antenna is that it does not require an additional antenna ground plane, which effectively stimulates the required operating bandwidth. However, stand-alone antennas are often susceptible to the surrounding environment, especially when there are metal components around the freestanding antenna, the impedance and radiation characteristics will change significantly.

The Republic of China Publication No. I277243 provides a multi-frequency antenna which is a self-contained antenna. The multi-frequency antenna adopts the structure of a dual-path planar inverted-F antenna to achieve the goal of multi-frequency operation, and the multi-frequency antenna has a simple structure and is easy to manufacture. However, according to the characteristics of the planar inverted-F antenna, there is a characteristic that the current distribution is weak at the end of the resonance path (relatively, the electric field at the end of the resonance path is strong), so there is a marginal field (fringing- Field) effect. When an object (and especially a metal object) is close to the multi-frequency antenna, the marginal field of the multi-frequency antenna is coupled with the adjacent object, thereby affecting the impedance and radiation characteristics of the multi-frequency antenna. Due to the above characteristics, the placement position of the multi-frequency antenna will be limited by the internal environment of the electronic device, thereby reducing the practical application value of the multi-frequency antenna.

The embodiment of the invention provides a stand-alone multi-frequency antenna, which comprises an antenna ground plane, a shielding metal wall, a first radiating element and a signal feeding source. The first radiating element is an antenna structure having a marginal field connected to at least one side of the antenna ground plane and above the antenna ground plane. The first radiating unit is configured to provide a first operating frequency band and a second operating frequency band. The shielding metal wall is connected to a plurality of sides adjacent to the ground plane of the antenna, and the height thereof is greater than or equal to the height of the first radiating unit to limit the marginal field of the first radiating unit to the independent multi-frequency antenna. The signal feeding source has a signal feeding point and a grounding point, wherein the signal feeding point is electrically connected to the first radiating unit, and the grounding point is electrically connected to the shielding metal wall.

The embodiment of the invention provides a stand-alone multi-frequency antenna, which comprises an antenna ground plane, a shielding metal wall, a first radiating element and a signal feeding source. The first radiating element is an antenna structure having a marginal field connected to at least one side of the antenna ground plane and above the antenna ground plane. The first radiating unit is configured to provide a first operating frequency band and a second operating frequency band. The shielding metal wall is connected to a plurality of sides adjacent to the ground plane of the antenna, and the height is related to a specific distance between the first radiating element and the shielding metal wall to limit the marginal field of the first radiating unit to the independent multi-frequency Inside the antenna. The signal feeding source has a signal feeding point and a grounding point, wherein the signal feeding point is electrically connected to the first radiating unit, and the grounding point is electrically connected to the shielding metal wall.

In summary, the independent multi-frequency antenna provided by the embodiment of the present invention has a shielded metal wall, and the shielded metal wall can effectively limit the marginal field of the independent multi-frequency antenna to the body structure of the independent multi-frequency antenna. Reduce the problem of coupling the marginal field to other components close to the stand-alone multi-frequency antenna. Accordingly, the stand-alone multi-frequency antenna of the embodiment of the present invention has the ability to withstand changes in the surrounding environment.

The detailed description of the present invention and the accompanying drawings are to be understood by the claims The scope is subject to any restrictions.

The independent multi-frequency antenna of the embodiment of the invention can be built in electronic devices of various network communication products, and can be designed to provide 2.4 GHz (2400-2484 MHz), 5.2 GHz (5150-5350 MHz) and 5.8. The operating band of GHz (5725 to 5825 MHz) serves as a communication band of the electronic device. In addition, the independent multi-frequency antenna of the embodiment of the present invention may be an antenna integrally formed by bending a single metal piece through a plurality of times. The various independent multi-frequency antennas provided by the embodiments of the present invention will be described in detail below.

[Embodiment of Independent Multi-Frequency Antenna]

Please refer to FIG. 1. FIG. 1 is a perspective view of a stand-alone multi-frequency antenna according to an embodiment of the present invention. The stand-alone multi-frequency antenna 1 includes an antenna ground plane 2, a shield metal wall 3, a first radiating element 4, a second radiating element 5, a signal feeding point 61, and a grounding point 62. The independent multi-frequency antenna 1 is an independently operable multi-frequency antenna, and may be an antenna structure integrally formed by a plurality of bendings of a single metal piece having a thickness of 0.3 mm, but the thickness of the single metal piece is not limit. The first radiating element 4 is substantially a structure of a planar inverted-F antenna, and the second radiating element 5 may be a parasitic plate.

According to the characteristics of the planar inverted-F antenna, it is known that there is a weak current distribution at the end of the resonant path (relatively, the electric field at the end of the resonant path is strong), so that a marginal field is generated. If a metal object is close, the edge field of the antenna will couple with the nearby metal object, which will cause the antenna characteristics to be significantly affected.

The first radiating element 4 of the independent multi-frequency antenna 1 has a marginal field at the end of the resonant path. Therefore, the shielding metal wall 3 is disposed on the side of the antenna ground plane 2 near the end of the first radiating element 4, so that The marginal field is limited to the independent multi-frequency antenna 1. Thus, when there is a metal object close to the stand-alone multi-frequency antenna 1, the stand-alone multi-frequency antenna 1 can reduce coupling with the metal object.

In short, the vertical shielded metal wall 3 in the independent multi-frequency antenna 1 can effectively limit the marginal field of the planar inverted-F antenna to the body structure of the independent multi-frequency antenna 1 to reduce the marginal field and the proximity independent. Other components of the multi-frequency antenna 1 can cause coupling problems. Accordingly, the stand-alone multi-frequency antenna 1 has the ability to withstand changes in the surrounding environment, so the stand-alone multi-frequency antenna 1 is more flexible in practical applications.

The detailed structure of the stand-alone multi-frequency antenna 1 of Fig. 1 will be described below. However, the configuration of the stand-alone multi-frequency antenna of the present invention is not limited thereto. 1 is only one embodiment of the present invention. Other independent multi-frequency antennas having a shielded metal wall and which can limit the marginal field to the body are also other embodiments of the present invention.

In the embodiment of FIG. 1, the antenna ground plane 2 has a first long side 21, a first short side 22, a second long side 23 and a second short side 24, wherein the first long side 21 and the second long side 23 are both Adjacent to the first short side 22 and the second short side 24, the first long side 21 is opposite to the second long side 23, and the first short side 22 is opposite to the second short side 24. The shield metal wall 3 is formed by a metal piece extending partially from the antenna ground plane 2, and the shield metal wall 3 and the antenna ground plane 2 are perpendicular to each other. More specifically, the shield metal wall 3 is formed of an L-shaped metal wall extending from the second long side 23 and the second short side 24. The shielding metal wall 3 has a first shielding portion 31 and a second shielding portion 32, wherein the first shielding portion 31 and the second shielding portion 32 are adjacent to each other. The first shielding portion 31 is connected to the second long side 23, the second shielding portion 32 is connected to the second short side 24, and the first shielding portion 31 and the second shielding portion 32 are perpendicular to the antenna ground plane 2. In addition, it should be noted that in other embodiments, it is also possible that the first shielding portion 31 and the second shielding portion 32 are adjacent to each other and are not actually connected.

The first radiating element 4 is located above the antenna ground plane 2, one end of the first radiating element 4 is connected to the first short side 22, and the first radiating element 4 extends in the direction of the first long side 21. The first radiating unit 4 is configured to provide a first operating frequency band and a second operating frequency band. The first radiating element 4 includes a first metal portion 41, a base metal portion 42 and a second metal portion 43, wherein the base metal portion 42 is connected between the first metal portion 41 and the second metal portion 43, and the first metal One end of the portion 41 is connected to the first short side 22.

The first metal portion 41 has at least one bend so that one end of the first metal portion 41 is connected to the first short side 22, and a portion of the first metal portion 41 is extended along the first long side 21 (ie, The direction of the second short side 24 extends). In short, the first metal portion 41 is bent into an L-shaped metal sheet body. The base metal portion 42 has a plurality of base metal segments which have at least three bends. One end of the base metal portion 42 is connected to the side of the first metal portion 41, and the other end of the base metal portion 42 is connected to the other side of the second metal portion 43. The second metal portion 43 is located in the extending direction of the first metal portion 41.

One end of the second radiating element 5 is connected to the first shield portion 31 of the shield metal wall 3, and the second radiating element 5 may be an L-shaped metal sheet body. One end of the second projecting unit 5 extends toward the first short side 22, and the body of the second radiating element 5 extends along the second long side 23 (i.e., extends in the direction of the second short side 24). The second radiating element 5 can be used to provide a third operating band.

In the embodiment of FIG. 1, the signal feed point 61 is disposed on the first metal portion 41, the ground point 62 is on the second radiating unit 5, and the signal feed point 61 and the ground point 62 are both disposed on the first metal. The portion 41 and the second radiating element 5 are on the side adjacent to each other. The grounding point 62 is electrically connected to the shielding metal wall 3 through the second radiating element 5. The signal feed point 61 and the ground point 62 constitute a signal feed source of the independent multi-frequency antenna 1. The electronic device can be connected to the independent multi-frequency antenna 1 through a signal feed transmission line, which can be, for example, a mini-coaxial line. The signal feed point 61 of the signal feed source (ie, the RF signal output end) is connected to the first radiating element 4, and the ground point 62 of the signal feed source is connected to the second radiating element 5.

Next, dimensions such as length, width, and pitch of the elements of the free-standing multi-frequency antenna 1 of FIG. 1 will be further described. However, it should be noted that the dimensions, widths, and pitches of the components of the stand-alone multi-frequency antenna 1 of FIG. 1 are not intended to limit the present invention. FIG. 1 is only one embodiment of the present invention.

In the embodiment of FIG. 1, the lengths of the first long side 21 and the second long side 23 are both 35 mm, and the lengths of the first short side 22 and the second short side 24 are both 12 mm. The length and width of the first shield portion 31 are 35 mm and 5 mm, respectively, and the length and width of the second shield portion 32 are 12 mm and 5 mm, respectively.

The side length of the first metal portion 41 connected to one end of the first short side 22 is 5.5 mm, and the length of the portion of the first metal portion 41 extending along the first long side 21 is L. The length L _MP of the base metal portion 42 extending along the first long side 21 and the length L _EP of the second metal portion 43 extending along the first long side 21 are 8.5 mm. In addition, the line width of the base metal segment is 0.5 mm (refer to Fig. 2), and the distance between the base metal segments is also 0.5 mm (refer to Fig. 2).

The distance between the second radiating element 5 and the first radiating element 4 is 2 mm, and the side length of the connecting side of the second radiating element 5 connected to the first shield portion 31 is 6 mm. The length of the main body of the second radiating element 5 is 17.5 (11.5+6) mm, the distance between the main body of the second radiating element 5 and the first shielding portion 31 is 1.5 mm, and the width of the main body of the second radiating element 5 is 3 (4.5-1.5) mm. The projections of the signal feed point 61 and the ground point 62 on the antenna ground plane 2 are both 3.5 mm from the first short side 21.

Please refer to FIG. 2. FIG. 2 is a plan view showing the unfolded multi-frequency antenna according to an embodiment of the present invention. The stand-alone multi-frequency antenna 1 of FIG. 1 may be formed by bending a metal sheet structure as described in FIG. 2, wherein the first shield portion 31 and the second shield portion 32 have a second long side 23 and a second portion, respectively. The short side 24 is formed by bending the shaft through 90 degrees to form the vertical shield metal wall 3 shown in FIG.

The first shielding portion 31 is further connected to the second radiating unit 5, and after the first shielding portion 31 and the second shielding portion 32 are bent, the second radiating unit 5 is connected to the second radiating unit 5 by the first shielding portion 31. The connecting side is such that the shaft is bent at 90 degrees to form the vertical second radiating element 5 shown in FIG. The first metal portion 41 is bent by 90 degrees with the first short side 22 as an axis, and then the first metal portion 41 and the first short side 22 are bent by a distance of 5 mm (the first metal portion 41 in FIG. 2). The upper dashed line 4 is the first radiation unit 4 shown in FIG. 1 after the shaft is bent by 90 degrees.

Please continue back to FIG. 1. Although the shielded metal wall 3 in the embodiment of FIG. 1 is perpendicular to the antenna ground plane 2, the shielded metal wall 3 only has 0 to 180 degrees from the antenna ground plane 2 (excluding 0 and 180). The angle of the degree can reduce the problem that the marginal field and the other components close to the independent multi-frequency antenna 1 will be coupled. On the whole, however, the shielding metal wall 3 is designed to have a better shielding effect perpendicular to the antenna ground plane 2, and the required width is also small.

In addition, although the antenna ground plane 2 in the embodiment of FIG. 1 is rectangular, it may actually be a polygonal antenna ground plane. At this time, the shield metal wall 3 is designed to limit the marginal field of the first radiating element 4 to the independent multi-frequency antenna. Therefore, the shield metal wall 3 is connected to a plurality of sides of the polygon antenna ground plane, and the antenna The ground plane has an angle other than zero. In addition, the first radiating element 4 may be an antenna structure having a marginal field extending from at least one side of the antenna ground plane 2.

In the embodiment of Fig. 1, the end of the first radiating element 4 has a certain distance from the shield metal wall 3. When the specific distance is small, the marginal field effect has a great influence on the metal object close to the independent multi-frequency antenna 1. Therefore, the height of the shielding metal wall 3 at this time (ie, the vertical distance between the shielding metal wall 3 and the antenna ground plane 2) ) is greater than or equal to the height of the first radiating element 4 (ie, the vertical distance between the shield metal wall 3 and the antenna ground plane 2). When the specific distance is large, the marginal field effect has less influence on the metal object close to the independent multi-frequency antenna 1, and therefore, the height of the shield metal wall 3 may be even smaller than the height of the first radiating element 4. In other words, the height of the shielding metal wall 3 is related to a specific distance between the end of the first radiating element 4 and the shielding metal wall 3, and when the specific distance is greater than a certain value, the height of the shielding metal wall 3 may be smaller than the first radiation. The height of unit 4.

In addition, the shielding metal wall 3 can be disposed at a side edge of the first radiating element 4 (the side edge can be, for example, an end, a side or another open end), and the side edge of the first radiating element 4 has a marginal field, but The marginal field at the end of the first radiating element 4 is the strongest. Therefore, the embodiment of Fig. 1 places the shielded metal wall 3 on the second short side 24.

In addition to this, as previously described, the shield metal wall 3 does not necessarily have to be perpendicular to the antenna ground plane 2. However, the height of the first radiating element 4 is also related to a specific distance between the end of the first radiating element 4 and the shield metal wall 3. In other words, if the specific distance between the end of the first radiating element 4 and the shield metal wall 3 is small, the height of the shield metal wall 3 must be greater than or equal to the height of the first radiating element 4. If the specific distance between the end of the first radiating element 4 and the shield metal wall 3 is large, the equivalent height of the shield metal wall 3 may also be smaller than the height of the first radiating element 4.

In the resonant path of the first radiating element 4, the plurality of bent base metal portions 42 can effectively control the first radiating element 4 by appropriately adjusting the bending times of the base metal segments and the length of the resonant path. The ratio of the first operating frequency band of the excitation to the operating frequency of the second operating frequency. Further, the length of the second radiating element 5 is about a quarter of a wavelength of the center frequency of the third operating band.

For example, if the first operating band and the second operating band are respectively 2.4 GHz (center frequency is 2442 MHz) and 5.8 GHz (center frequency is 5775 MHz) operating band, then only the adjustment of the base metal segment is adjusted. The number of bends of 42 and the length of the resonant path are such that the ratio of the center frequency of the first operating band to the second operating band is about 1:2. In addition, the length of the second radiating element 5 can be adjusted so that the third operating band is a communication band of 5.2 GHz (center frequency is 5250 MHz). In this way, the third operating band and the second operating band can be combined into a wider operating band, so that the independent multi-frequency antenna 1 can perform multi-frequency operation (operating in an operating band near 2.4 GHz and 5.2 GHz to 5.8 GHz). Operating band).

Next, please refer to FIG. 3. FIG. 3 is a graph of return loss of the independent multi-frequency antenna according to the embodiment of the present invention. The return loss in Figure 3 is measured under the definition of a voltage standing wave ratio (VSWR) of 2.5:1. As can be seen from Figure 3, the stand-alone multi-frequency antenna 1 of Figure 1 can be operated. Operating band around 2.4 GHz and operating band between 5.2 GHz and 5.8 GHz. In addition, the independent multi-frequency antenna 1 has an impedance bandwidth that meets the return loss requirement of 7.3 dB.

Next, please refer to FIG. 4. FIG. 4 is a field diagram of the independent multi-frequency antenna operating in the 2.4 GHz band at a center frequency of 2442 MHz according to an embodiment of the present invention. In the graph of E _θ and E _φ in Fig. 4, the stronger one is the main polarization curve, and the weaker one is the cross polarization curve. It can be seen from the field diagrams of the xz plane, the yz plane and the xy plane in FIG. 4 that when the independent multi-frequency antenna 1 of FIG. 1 operates at a center frequency of 2442 MHz, the independent multi-frequency antenna 1 is an approximate omnidirectional radiation antenna.

Next, please refer to FIG. 5. FIG. 5 is a field diagram of the independent multi-frequency antenna operating in the 5.2 GHz band at a center frequency of 5250 MHz according to an embodiment of the present invention. In the graph of E _θ and E _φ in Fig. 5, the stronger one is the main polarization curve, and the weaker one is the cross polarization curve. From the field diagrams of the xz plane, the yz plane and the xy plane in FIG. 5, the independent multi-frequency antenna 1 of FIG. 1 operates at a center frequency of 5250 MHz, and the independent multi-frequency antenna 1 is an approximate omnidirectional radiation antenna.

Next, please refer to FIG. 6. FIG. 6 is a field diagram of the independent multi-frequency antenna operating in the 5.8 GHz band at a center frequency of 5775 MHz according to an embodiment of the present invention. In Fig. 6, the strongest of the curves of E _θ and E _{φ is} the main polarization curve, and the weaker one is the cross polarization curve. From the field diagrams of the xz plane, the yz plane and the xy plane in FIG. 6, it can be seen that when the independent multi-frequency antenna 1 of FIG. 1 operates at a center frequency of 5775 MHz, the independent multi-frequency antenna 1 is an approximately omnidirectional radiation antenna.

Please refer to FIG. 1 and FIG. 7. FIG. 7 is a graph of return loss of the independent multi-frequency antenna according to the embodiment of the present invention. The length L _MP of the base metal portion 42 extending along the first long side 21 and the length L _EP of the second metal portion 43 extending along the first long side 21 are 8.5 mm, but the length L _MP and the L _EP can be adjusted. To adjust the return loss of the free-standing multi-frequency antenna 1. In FIG. 7, it can be found that when the length L _{MP of the base} metal portion 42 extending along the first long side 21 becomes larger, the return loss of the third operating band becomes larger and the center frequency thereof slightly rises. The return loss of the second operating band does not change much but its center frequency drops significantly. It can be seen from Fig. 7 that if the bandwidth of the second and third operating bands can cover both the 5.8 GHz and 5.2 GHz communication bands, the lengths L _MP and L _EP can be designed to be 5.5 mm and 3 mm, respectively.

Please refer to FIG. 1 and FIG. 8. FIG. 8 is a graph showing the return loss of the independent multi-frequency antenna according to the embodiment of the present invention. The length L of the portion of the first metal portion 41 that extends along the first long side 21 can be adjusted to adjust the center frequencies of the first to third operating bands. As can be seen from Fig. 8, the larger the length L, the lower the center frequency of the first and second operating bands is, and the center frequency of the third operating band is slightly increased. It can be seen from Fig. 7 that if the bandwidth of the first to third operating bands can cover the communication bands of 2.4 GHz, 5.8 GHz and 5.2 GHz, the length L can be designed to be 15.5 mm.

Please refer to FIG. 9. FIG. 9 is a graph showing antenna gain and radiation efficiency of a stand-alone multi-frequency antenna according to an embodiment of the present invention. 9 is an antenna gain and radiation efficiency measured using the free-standing multi-frequency antenna 1 of FIG. 1. In FIG. 9, it can be seen that the radiation efficiency and antenna gain in the operating bands of 2.4 GHz, 5.2 GHz, and 5.8 GHz are both It can reach at least 60% and 1 dB (dBi) or more.

[Another embodiment of a stand-alone multi-frequency antenna]

Please refer to FIG. 10. FIG. 10 is a perspective view of a stand-alone multi-frequency antenna according to another embodiment of the present invention. The difference between the stand-alone multi-band antenna 7 of FIG. 10 and the stand-alone multi-band antenna 1 of FIG. 1 is that the meandering direction of the base metal segments in the base metal portion 42' of the first radiating element 4' in FIG. The meandering of the base metal segments in the base metal portion 42 of the first radiating element 4 in FIG. It can be seen from the embodiment of Fig. 10 that the meandering direction of the base metal segments is not intended to limit the invention.

[Another embodiment of a stand-alone multi-frequency antenna]

Please refer to FIG. 11. FIG. 11 is a perspective view of a stand-alone multi-frequency antenna according to another embodiment of the present invention. The difference between the stand-alone multi-frequency antenna 8 of FIG. 11 and the stand-alone multi-band antenna 1 of FIG. 1 is that the second radiating element 5' of the second radiating element in FIG. 11 is not a parasitic metal piece of a shielded metal wall, and the second radiation The unit 5' has at least one bend, one end of which is connected to the first short side of the antenna ground plane, and the part of the second radiating element 5' extends along the first long side of the antenna ground plane (ie, toward the antenna The second short side of the ground extends). It can be seen from the embodiment of Fig. 11 that the position and size of the second radiating element are not intended to limit the invention.

[Another embodiment of a stand-alone multi-frequency antenna]

Please refer to FIG. 12. FIG. 12 is a perspective view of a stand-alone multi-frequency antenna according to another embodiment of the present invention. The difference between the stand-alone multi-frequency antenna 9 of FIG. 12 and the stand-alone multi-band antenna 1 of FIG. 1 is that the second radiating element is absent in FIG. 12, and because the second radiating element is absent, the grounding point 62' will be located in the shielding metal. The first shield of the wall. The grounding point 62' of the signal feed source is connected to the shield metal wall, and the signal feed point 61' of the signal feed source is connected to the first radiating element. It can be seen from the embodiment of Fig. 12 that the presence or absence of the second radiating element is not intended to limit the invention. Additionally, in other types of embodiments, the stand-alone multi-frequency antenna may include not only a second radiating element, but may further include a third radiating element.

[Another embodiment of a stand-alone multi-frequency antenna]

Please refer to FIG. 13. FIG. 13 is a perspective view of a stand-alone multi-frequency antenna according to another embodiment of the present invention. The difference between the stand-alone multi-frequency antenna 10 of FIG. 13 and the stand-alone multi-band antenna 1 of FIG. 1 is that the shielded metal wall 3' of the stand-alone multi-frequency antenna 10 is not perpendicular to the antenna ground plane 2' but to the antenna ground plane. There is an angle of 30 degrees between 2'. However, in this embodiment, the height of the shield metal wall 3' (i.e., the vertical distance from the antenna ground plane 2') is still greater than or equal to the height of the first radiating element.

[Embodiment of a stand-alone multi-frequency antenna applied to an electronic device]

The independent multi-frequency antenna of the embodiment of the invention can be applied to various electronic devices, because the independent multi-frequency antenna has a shielding metal wall perpendicular to the ground plane of the antenna, which can generate a marginal field generated by the end of the first radiating element. Partially limited to the structure of the independent multi-frequency antenna, thereby reducing the influence of other components inside the electronic device on the independent multi-frequency antenna. Please refer to FIG. 14. FIG. 14 is a schematic diagram of a stand-alone multi-frequency antenna applied to a notebook computer according to an embodiment of the present invention. The notebook computer 99 has an electronic component 91, a support ground plane 92 for supporting the liquid crystal display device, a main ground plane 93, and a stand-alone multi-band antenna 1'. The free-standing multi-frequency antenna 1' is disposed beside the electronic component 91, and the electronic component 91 is disposed on the center line CL of the support ground plane 92. The electronic component 91 and the free-standing multi-frequency antenna 1' are both disposed on the top side of the support ground plane 92, and the electronic component 91 is only 1 mm away from the free-standing multi-frequency antenna 1'.

In this embodiment, the independent multi-frequency antenna 1' impedance bandwidth can meet the return loss requirement of 7.3 decibels (dB) (assuming a voltage standing wave ratio of 2.5:1), and the independent multi-frequency antenna 1' Still can have good radiation characteristics. Further, it should be noted that the stand-alone multi-frequency antenna 1' may be a stand-alone multi-frequency antenna in each of the above embodiments. In addition, the notebook computer 99 may further include more than one stand-alone multi-frequency antenna 1' to form a notebook computer 99 having a multiple input multiple output antenna system.

[Possible efficacy of the embodiment]

In summary, the independent multi-frequency antenna of the embodiment of the invention has a shielding metal wall connected to the grounding surface of the antenna, and the shielding metal wall can effectively limit the marginal field of the independent multi-frequency antenna to the independent multi-frequency antenna. In the body structure, the problem of coupling the marginal field to other components close to the independent multi-frequency antenna is reduced. Accordingly, the stand-alone multi-frequency antenna of the embodiment of the present invention has the ability to withstand changes in the surrounding environment. At the same time, according to the foregoing measurement results, the independent multi-frequency antenna of the embodiment of the invention has good radiation efficiency and antenna gain.

In addition, the independent multi-band antenna of the embodiment of the present invention does not require an additional antenna ground plane, which can effectively excite various operating frequency bands, compared to the conventional planar inverted-F antenna. In addition, the independent multi-frequency antenna of the embodiment of the invention has the characteristics of simple fabrication and small size, and thus can be widely applied to electronic devices of different network communication products (for example, a notebook computer and a wireless liquid crystal display). In a device or other multimedia playback device with wireless communication capabilities, etc.).

Incidentally, in view of the increasing number of electronic devices in the market that use multi-input multi-output (MIMO) communication products, the independent multi-frequency antenna of the embodiment of the present invention It can be extended to use in electronic devices using multiple inputs and multiple outputs. In other words, a plurality of independent multi-frequency antennas of the embodiments of the present invention can be built in the same electronic device. Accordingly, the stand-alone multi-frequency antenna of the embodiment of the present invention has considerable flexibility and extensibility in practical applications.

The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.

1. . . Stand-alone multi-frequency antenna

2. . . Antenna ground plane

twenty one. . . First long side

twenty two. . . First short side

twenty three. . . Second long side

twenty four. . . Second short side

3. . . Shielded metal wall

31. . . First shield

32. . . Second shield

4. . . First radiation unit

41. . . First metal part

42. . . Metal parts

43. . . Second metal part

5. . . Second radiating element

61. . . Signal feed point

62. . . Grounding point

7. . . Stand-alone multi-frequency antenna

4’. . . First radiation unit

42’. . . Metal parts

8. . . Stand-alone multi-frequency antenna

5’. . . Second radiating element

9. . . Stand-alone multi-frequency antenna

61’. . . Signal feed point

62’. . . Grounding point

99. . . Notebook computer

1'. . . Stand-alone multi-frequency antenna

91. . . Electronic component

92. . . Support ground plane

93. . . Main ground plane

1 is a perspective view of a stand-alone multi-frequency antenna according to an embodiment of the present invention.

2 is a plan view of the independent multi-frequency antenna according to an embodiment of the present invention after deployment.

3 is a graph showing the return loss of a stand-alone multi-frequency antenna according to an embodiment of the present invention.

4 is a field diagram of a stand-alone multi-band antenna operating at a center frequency of 2442 MHz in the 2.4 GHz band according to an embodiment of the present invention.

5 is a field diagram of a stand-alone multi-band antenna operating at a center frequency of 5250 MHz in the 5.2 GHz band according to an embodiment of the present invention.

6 is a field diagram of a stand-alone multi-band antenna operating at a center frequency of 5775 MHz in the 5.8 GHz band according to an embodiment of the present invention.

Figure 7 is a graph showing the return loss of a stand-alone multi-frequency antenna according to an embodiment of the present invention.

Figure 8 is a graph showing the return loss of a stand-alone multi-frequency antenna according to an embodiment of the present invention.

9 is a graph showing antenna gain and radiation efficiency of a stand-alone multi-frequency antenna according to an embodiment of the present invention.

FIG. 10 is a perspective view of a stand-alone multi-frequency antenna according to another embodiment of the present invention.

11 is a perspective view of a stand-alone multi-frequency antenna according to another embodiment of the present invention.

FIG. 12 is a perspective view of a stand-alone multi-frequency antenna according to another embodiment of the present invention.

FIG. 13 is a perspective view of a stand-alone multi-frequency antenna according to another embodiment of the present invention.

14 is a schematic diagram of a stand-alone multi-frequency antenna applied to a notebook computer according to an embodiment of the present invention.

1. . . Stand-alone multi-frequency antenna

2. . . System ground plane

twenty one. . . First long side

twenty two. . . First short side

twenty three. . . Second long side

twenty four. . . Second short side

3. . . Shielded metal wall

31. . . First shield

32. . . Second shield

4. . . First radiation unit

41. . . First metal part

42. . . Metal parts

43. . . Second metal part

5. . . Second radiating element

61. . . Signal feed point

62. . . Grounding point

Claims (18)

A stand-alone multi-frequency antenna comprising: an antenna ground plane having a rectangular shape and having a first long side, a first short side, a second long side and a second short side; a first radiation The unit is an antenna structure having a side field, located above the ground plane of the antenna, for providing a first operating frequency band and a second operating frequency band, comprising: a first metal portion having at least one bend, One end is electrically connected to the first short side of the ground plane of the antenna, and the other end extends toward the second short side of the antenna ground plane; a second metal portion is located in an extending direction of the first metal portion; a base metal portion between the first and second metal portions, having a plurality of base metal segments; a shield metal wall connected to the second long side and the second short side adjacent to the ground plane of the antenna, The height of the shielding metal wall is greater than or equal to the height of the first radiating element to limit the marginal field of the first radiating element to the independent multi-frequency antenna; and a signal feeding source having a signal feed Point with a ground point, where No feeding point electrically connected to the first radiating element and the ground point electrically connected to the shielding metal wall. The independent multi-frequency antenna of claim 1, wherein the shielding metal wall is perpendicular to the antenna ground plane. The independent multi-frequency antenna according to claim 2, wherein the shielding metal wall has a first and second shielding portions adjacent to each other, and the first and second shielding portions are respectively connected to the grounding surface of the antenna The second long side of the neighbor and the first Two short sides. The independent multi-frequency antenna according to claim 1, wherein one end of the base metal portion is connected to one side of the first metal portion, and the other end of the base metal portion is connected to the second metal portion. The other side. The independent multi-frequency antenna of claim 1, further comprising: a second radiating unit, one end of which is electrically connected to the shielding metal wall, and the other end of which extends toward the second short side, a portion of the second radiating element extending toward the second short side also extends along the direction of the first long side, the second radiating unit is configured to provide a third operating frequency band; wherein the grounding point is connected to the second radiation unit. The independent multi-frequency antenna according to claim 5, wherein the shielding metal wall is an L-shaped metal wall, and the second radiating element is an L-shaped metal piece. The independent multi-frequency antenna according to claim 1, wherein the length of the second metal portion and the base metal portion extending along the first longitudinal direction is 8.5 mm. The independent multi-band antenna of claim 5, wherein the first to the third operating bands are operating bands close to 2.4 GHz, 5.8 GHz, and 5.2 GHz, respectively. The independent multi-frequency antenna according to claim 5, wherein the free-standing multi-frequency antenna is integrally formed by bending a metal piece through a plurality of times, and the metal piece has a thickness of 0.3 mm. The independent multi-frequency antenna of claim 1, wherein the base metal segments are bent at least 3 times, and the base metal segments have a line width of 0.5 mm. The independent multi-frequency antenna of claim 7, wherein the second metal portion and the base metal portion extend along the first longitudinal direction by a length of 3 mm and 5.5 mm, respectively. The length of the metal portion extending along the first longitudinal direction is 15.5 mm, and the first and second radiating elements are spaced apart by 2 mm. The independent multi-frequency antenna according to claim 5, wherein the second radiating element is a parasitic metal piece of the shielding metal wall, and the shielding metal wall is connected along the direction of the first long side. The extension length is 17.5 mm. The independent multi-frequency antenna according to claim 5, wherein the second radiating unit has at least one bend, one end of the second radiating unit is connected to the first short side, and the second radiating unit is further One end extends toward the second short side. The independent multi-band antenna of claim 5, wherein the signal feed point and the projection of the ground point on the ground plane of the antenna are both 3.5 mm apart from the first short side. A stand-alone multi-frequency antenna comprising: an antenna ground plane having a rectangular shape and having a first long side, a first short side, a second long side and a second short side; a first radiation The unit is an antenna structure having a side field, located above the ground plane of the antenna, for providing a first operating frequency band and a second operating frequency band, comprising: a first metal portion having at least one bend, One end of the antenna is electrically connected to the first short side of the ground plane of the antenna, and the other end of the antenna is connected to the second short side of the ground plane of the antenna; a second metal portion is located at an extending direction of the first metal portion; And a metal portion between the first and second metal portions, having a plurality of base metal segments; a shield metal wall connected to the second long side adjacent to the antenna ground plane and the second a short side, the height of the shielding metal wall is related to a specific distance between the first radiating element and the shielding metal wall to limit the marginal field of the first radiating unit to the independent multi-frequency antenna; A signal feeding source has a signal feeding point and a grounding point, wherein the signal feeding point is electrically connected to the first radiating unit, and the grounding point is electrically connected to the shielding metal wall. The independent multi-frequency antenna according to claim 15, wherein when the specific distance is greater than a specific value, the height of the shielding metal wall is smaller than the height of the first radiation unit; when the fixed distance is less than the specific value, The height of the shielding metal wall is greater than or equal to the height of the first radiating element. The independent multi-frequency antenna according to claim 16, wherein the shielding metal wall is perpendicular to the antenna grounding surface, and the shielding metal wall has a first and second shielding portions adjacent to each other, the first and the second The second shielding portion is respectively connected to the second long side and the second short side adjacent to the antenna ground plane. The independent multi-frequency antenna according to claim 17, wherein one end of the base metal portion is connected to one side of the first metal portion, and the other end of the base metal portion is connected to the second metal portion. The other side.