TWI528630B - Handheld device - Google Patents

Description

Handheld device

The present invention relates to a hand-held device, and more particularly to a hand-held device having dual antennas.

Most of today's handheld devices use a multi-antenna system to accommodate the range of reception under different communication standards. For example, in the GSM900/DCS1800/UMTS band, the mobile phone must have two separate antennas to modulate two different RF signals, such as GSM and W-CDMA signals in the UMTS band. In addition, in the case of a complex antenna system, in order to avoid mutual interference between the antennas and the resonance between the antenna and the system ground plane, the isolation between the antennas is very important.

Most existing handheld devices increase the isolation of the antenna by increasing the distance between the antennas. For example, in U.S. Patent No. 6,045,955, the horizontal spacing between two antennas must be defined to be set at an odd multiple of 1/4 of the RF wavelength to thereby reduce interference and radiation effects between the two antennas. However, this practice often consumes a large amount of hardware space, which in turn limits the development of handheld devices in miniaturization.

Therefore, how to set up two independent antennas in a limited space, and at the same time taking into account the receiving quality of the two antennas, has been a problem to be solved in the design of the handheld device.

The present invention provides a hand-held device that improves the isolation between antennas by adjusting the feed points and ground points of the two antennas. Thereby, the two antennas in the handheld device can be placed in a limited antenna area and maintain good reception quality.

The invention provides a handheld device comprising a first antenna and a second antenna. The first antenna has a first ground point and a first feed point, and operates in the first frequency band, wherein the first ground point and the first feed point are sequentially disposed along the horizontal direction. The second antenna has a second ground point and a second feed point, and operates in the second frequency band, wherein the second ground point and the second feed point are sequentially disposed along the horizontal direction. Furthermore, the central operating frequency of the first frequency band is lower than the central operating frequency of the second frequency band, and the horizontal spacing between the first grounding point and the second grounding point, and between the first feeding point and the second feeding point The horizontal spacing depends on the central operating frequency of the first frequency band.

In an embodiment of the invention, the handheld device further includes a substrate. The substrate has an antenna region, and the first antenna and the second antenna are disposed in the antenna region. In addition, the handheld device further includes a ground plane. The ground layer is disposed on the substrate and surrounds the antenna region.

In an embodiment of the invention, the horizontal spacing between the first ground point and the second ground point is equal to the horizontal spacing between the first feed point and the second feed point.

Based on the above, the present invention improves the isolation between the antennas by adjusting the horizontal spacing of the feed points of the two antennas and the horizontal spacing of the ground points. As a result, as the isolation of the antenna increases, unnecessary power loss of the antenna can be reduced, thereby increasing the total radiation efficiency of the antenna. In other words, the two antennas of the present invention can be placed in a limited antenna area and maintain good reception quality.

The above described features and advantages of the present invention will be more apparent from the following description.

1 is a schematic illustration of a handheld device in accordance with an embodiment of the present invention. Referring to FIG. 1, the handheld device 100 includes a substrate 110 and a camera module 120, a speaker 130, and a battery 140 disposed on the substrate 110. A ground layer 111 and an antenna region 112 are further disposed on the substrate 110 , and the ground layer 111 surrounds the antenna region 112 . In addition, two independent antennas are disposed in the antenna area 112, and the handheld device 100 improves the isolation between the antennas by adjusting the feeding points and grounding points of the two antennas. Thereby, two separate antennas can be placed in the limited antenna area 112 and maintain good reception quality.

In order to make the present invention more familiar to those skilled in the art, FIG. 2 is a partial enlarged view of a handheld device according to an embodiment of the present invention, and the following will further improve the two independent antennas in the handheld device 100. Description.

Referring to FIG. 2, the handheld device 100 further includes a first antenna 210 and a second antenna 220. The first antenna 210 and the second antenna 220 are both disposed in the antenna region 112. In addition, the first antenna 210 and the second antenna 220 may be, for example, Planar Inverted F Antenna (PIFA). Operationally, the first antenna 210 is operating in a first frequency band, the second antenna 220 is operating in a second frequency band, and the central operating frequency of the first frequency band is lower than a central operating frequency of the second frequency band. For example, the first frequency band can be, for example, a frequency band under the GSM850/EGSM specification, and the second frequency band is, for example, a frequency band under the DCS/PCS/UMTS specification. In other words, for the handheld device 100, the first antenna 210 can be considered as a low frequency antenna of the system, and the second antenna 220 can be regarded as a high frequency antenna of the system.

In configuration, the first antenna 210 has a first ground point G1 and a first feed point F1, and the second antenna 220 has a second ground point G2 and a second feed point F2. The first grounding point G1 and the first feeding point F1 of the first antenna 210 are sequentially disposed along a horizontal direction DT2, that is, the first grounding point G1 and the first feeding point F1 are left to right. The ground is sequentially disposed on the first antenna 210. On the other hand, the second grounding point G2 and the second feeding point F2 of the second antenna 220 are also sequentially arranged along the horizontal direction DT2, that is, the second grounding point G2 and the second feeding point F2 are also left to the left. The right side is sequentially disposed on the second antenna 220.

In addition, in the embodiment of FIG. 2, the second grounding point G2, the first grounding point G1, and the first feeding point F1 are located on a horizontal line, and the second feeding point F2 and the second grounding point G2 are not set. At the same level. However, although the embodiment of FIG. 2 cites the preferred arrangement of the grounding points G1 and G2 and the feeding points F1 and F2 with respect to the same horizontal line, it is not intended to limit the present invention, and those skilled in the art may If necessary, arbitrarily change the setting of the grounding points G1, G2 and the feeding points F1 and F2 with respect to the same horizontal line.

Further, the horizontal spacing D21 between the first grounding point G1 and the second grounding point G2, and the horizontal spacing D22 between the first feeding point F1 and the second feeding point F2 are both dependent on the first frequency band. The central operating frequency. That is to say, the lengths of the horizontal spacing D21 and the horizontal spacing D22 are both dependent on the central operating frequency of the low frequency antenna. Further, the horizontal pitch D21 is equal to the horizontal pitch D22, and when the wavelength corresponding to the central operating frequency of the first frequency band is represented as λ, the horizontal pitches D21 and D22 are between λ/40 and λ/20. Here, by adjusting the relative position of the grounding point of the antenna and the feeding point, the coupling effect between the first antenna 210 and the second antenna 220 can be reduced, thereby improving the first antenna 210 and the second antenna. 220 isolation.

For example, in the embodiment of Figure 2, the horizontal spacings D21 and D22 are greater than λ/40. In addition, FIG. 3 is a diagram illustrating a transmission coefficient of the antenna of the embodiment of FIG. 2, wherein the horizontal axis is used to indicate the center operating frequency of the antenna, and the vertical axis is used to indicate the antenna's penetration coefficient S ₂₁ . As shown in FIG. 3, when the horizontal spacings D21 and D22 are greater than λ/40, the isolation of the first antenna 210 operating in the GSM850/EGSM band can be increased to -4~-6dB.

In another aspect, Figure 4 is a partial enlarged view of a handheld device in accordance with another embodiment of the present invention. Please refer to FIG. 2 and FIG. 4 at the same time, the biggest difference between the two is that the horizontal spacings D21 and D22 in the embodiment of FIG. 2 are greater than λ/40, and the horizontal spacings D21' and D22' in the embodiment of FIG. 4 are The phase is equal to λ/40. Therefore, in the embodiment of Fig. 4, the horizontal pitch D21' and the horizontal pitch D22' do not overlap each other. On the contrary, in the embodiment of Fig. 2, the horizontal pitch D21 and the horizontal pitch D22 overlap each other.

However, regardless of whether the horizontal pitch D21 and the horizontal pitch D22 overlap each other, as long as the horizontal pitch D21 and the horizontal pitch D22 fall between λ/40 and λ/20, the isolation between the first antenna 210 and the second antenna 220 Can be relatively increased. For example, FIG. 5 is a diagram illustrating a transmission coefficient of an antenna of the embodiment of FIG. 3, wherein the horizontal axis is used to indicate the operating frequency of the antenna, and the vertical axis is used to indicate the penetration coefficient S _{21 of the} antenna. As shown in FIG. 5, when the horizontal spacings D21 and D22 are equal to λ/40, the isolation of the first antenna 210 operating in the GSM850/EGSM band can be increased to -20~-30dB, and the operation is performed. The isolation of the second antenna 220 in the DCS/PCS/UMTS band will approach -15 dB.

It is worth mentioning that, as shown by equations (1) and (2), the larger the penetration coefficient S ₂₁ , the higher the total radiation efficient of the antenna. It is also known that the gain of the antenna is proportional to the total radiation efficiency of the antenna, so as the total radiation efficiency of the antenna increases, the gain of the antenna will also increase relatively. In other words, as the isolation between the first antenna 210 and the second antenna 220 increases, the average gain of the first antenna 210 and the second antenna 220 can be correspondingly increased, thereby helping to increase the first day. The reception quality of the line 210 and the second antenna 220.

η _tot1 =η _ray1 (1-|S ₁₁ | ² -|S ₂₁ | ² ) Equation (1)

η _tot2 =η _ray2 (1-|S ₂₂ | ² -|S ₁₂ | ² ) Equation (2)

For example, for the first antenna 210 operating in the GSM850/EGSM band, when the horizontal spacings D21 and D22 are greater than and equal to λ/40, the measured average gain is as shown in Table 1. Referring to Table 1, compared to the case where the horizontal spacings D21 and D22 are set larger than λ/40, when the horizontal spacings D21 and D22 are set at λ/40, the average gain of the first antenna 210 will be 1.88 higher. dB.

On the other hand, for the second antenna 220 operating in the DCS/PCS/UMTS band, when the horizontal spacings D21 and D22 are greater than and equal to λ/40, the measured average gain will be as shown in Table 2. . Referring to Table 2, the average gain of the second antenna 220 is higher than 1.1 when the horizontal spacings D21 and D22 are set at λ/40 compared to the case where the horizontal spacings D21 and D22 are set larger than λ/40. dB.

In addition, the isolation between the first antenna 210 and the second antenna 220 can also be improved by adjusting the frequency ratio of the first antenna 210 operating in the first frequency band.

For example, FIG. 6 is a partial enlarged view of a handheld device in accordance with still another embodiment of the present invention. Referring to FIG. 4 and FIG. 6 at the same time, the biggest difference between the two is that the embodiment of FIG. 6 changes the shape of the radiating portion of the first antenna 210' to cause the first antenna 210' to operate in the first frequency band. The frequency ratio is greater than 3. As such, the isolation of the first antenna 210' in the embodiment of Fig. 6 will be 5 dB higher than in the first antenna 210 of the embodiment of Fig. 4. In addition, the isolation of the second antenna 210 in the embodiment of FIG. 6 will be 2 to 3 dB higher than that of the second antenna 220 in the embodiment of FIG.

In addition, FIG. 7 is a partial enlarged view of a handheld device in accordance with still another embodiment of the present invention. Referring to FIG. 4 and FIG. 7 at the same time, the biggest difference between the two is that the embodiment of FIG. 7 changes the shape of the radiating portion of the first antenna 210" so that the first antenna 210" operates in the first frequency band. The frequency ratio is less than 3. As such, the isolation of the first antenna 210" in the embodiment of FIG. 7 will be 1 to 3 dB higher than the first antenna 210 in the embodiment of FIG.

In summary, the present invention improves the isolation between the antennas by adjusting the horizontal spacing of the feed points of the two antennas and the horizontal spacing of the ground points. As a result, as the isolation of the antenna increases, unnecessary power loss of the antenna can be reduced, thereby increasing the total radiation efficiency of the antenna. In other words, the two antennas of the present invention can be placed in a limited antenna area and maintain good reception quality.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements 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. . . Handheld device

110. . . Substrate

111. . . Ground plane

112. . . Antenna area

120. . . Camera module

130. . . speaker

140. . . battery

210, 210', 210"... first antenna

220. . . Second antenna

G1. . . First grounding point

F1. . . First feed point

G2. . . Second grounding point

F2. . . Second feed point

DT2. . . horizontal direction

D21, D22, D21', D22'. . . Horizontal spacing

S ₂₁ . . . Penetration coefficient

1 is a schematic illustration of a handheld device in accordance with an embodiment of the present invention.

2 is a partial enlarged view of a handheld device in accordance with an embodiment of the present invention.

FIG. 3 is a view showing a penetration coefficient of the antenna of the embodiment of FIG. 2. FIG.

4 is a partial enlarged view of a handheld device in accordance with another embodiment of the present invention.

Figure 5 is a diagram for explaining the penetration coefficient of the antenna of the embodiment of Figure 3.

Figure 6 is a partial enlarged view of a hand-held device in accordance with still another embodiment of the present invention.

Figure 7 is a partial enlarged view of a handheld device in accordance with still another embodiment of the present invention.

110. . . Substrate

111. . . Ground plane

112. . . Antenna area

210. . . First antenna

220. . . Second antenna

G1. . . First grounding point

F1. . . First feed point

G2. . . Second grounding point

F2. . . Second feed point

DT2. . . horizontal direction

D21, D22. . . Horizontal spacing

Claims (7)

A handheld device includes: a first antenna having a first ground point and a first feed point, and operating in a first frequency band, and the first ground point and the first feed point along a horizontal direction is sequentially disposed; a second antenna has a second ground point and a second feed point, and operates in a second frequency band, and the second ground point and the second feed point are along The horizontal direction is sequentially disposed; a substrate having an antenna region, wherein the first antenna and the second antenna are disposed in the antenna region; and a ground layer disposed on the substrate and surrounding the antenna region The central operating frequency of the first frequency band is lower than a central operating frequency of the second frequency band, and a horizontal spacing between the first grounding point and the second grounding point, and the first feeding point and the first The horizontal spacing between the two feed points depends on the central operating frequency of the first frequency band. The hand-held device of claim 1, wherein a horizontal spacing between the first ground point and the second ground point is equivalent to between the first feed point and the second feed point Horizontal spacing. The hand-held device of claim 1, wherein the wavelength corresponding to the central operating frequency of the first frequency band is represented as λ, and the horizontal spacing between the first grounding point and the second grounding point is λ/ 40 to λ/20. The handheld device of claim 1, wherein a wavelength corresponding to a central operating frequency of the first frequency band is represented as λ, and the first The horizontal distance between the feed point and the second feed point is between λ/40 and λ/20. The hand-held device of claim 1, wherein the second grounding point, the first grounding point, and the first feeding point are on a horizontal line. The hand-held device of claim 5, wherein the second feed point is not disposed on the horizontal line. The hand-held device of claim 1, wherein the first antenna and the second antenna are planar inverted-F antennas.