TWI583059B - Wireless communication device - Google Patents

Description

Wireless communication device

The present invention relates to a wireless communication device, and more particularly to a wireless communication device including two antennas.

With the rapid development of wireless communication technologies, the operating frequency bands available for wireless communication devices are constantly increasing, thereby enhancing the application of wireless resources. For example, the operating frequency bands used in the fourth generation of mobile communications include 700 MHz, 699 MHz to 960 MHz, 2600 MHz, and 2500 MHz to 2690 MHz. In addition, as the operating frequency band increases, the wireless communication device must also provide multiple antennas correspondingly to support multiple operating frequency bands. However, the hardware space of wireless communication devices is limited. Therefore, how to provide multiple antennas in a limited space of a wireless communication device and to take into consideration the isolation between antennas has become an important issue.

The invention provides a wireless communication device, which uses an adjustment circuit to adjust an operating frequency of a first antenna in a resonant mode or an impedance matching of a first antenna in a resonant mode. Thereby, the isolation between the first antenna and the second antenna can be increased, thereby contributing to an increase in the receiving quality of the wireless communication device.

The wireless communication device of the present invention comprises a first antenna, a second antenna and an adjustment circuit. The first antenna receives or emits electromagnetic waves through a resonant mode. The second antenna operates in at least one frequency band, wherein at least one harmonic bit in the resonant mode of the first antenna is in at least one frequency band. The adjustment circuit is electrically connected to the first antenna. When the second antenna operates in the at least one frequency band, the adjusting circuit adjusts an operating frequency of the first antenna in a resonant mode or adjusts impedance matching of the first antenna in a resonant mode.

In an embodiment of the invention, when the wireless communication device disables the second antenna, the adjusting circuit switches the first antenna to the first mode, so that the first antenna transmits through the resonant mode or Emission of electromagnetic waves. In addition, when the wireless communication device enables the second antenna, the adjusting circuit switches the first antenna to the second mode to adjust the operating frequency of the first antenna in the resonant mode, or adjust the first day. The impedance matching of the line in the resonant mode.

Based on the above, the wireless communication device of the present invention adjusts the operating frequency of the first antenna in the resonant mode or adjusts the impedance of the first antenna in the resonant mode when the second antenna is enabled. match. Thereby, the isolation between the first antenna and the second antenna can be increased, thereby contributing to an increase in the receiving quality of the wireless communication device.

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

1 is a schematic diagram of a wireless communication device in accordance with an embodiment of the present invention. As shown in FIG. 1, the wireless communication device 100 includes a first antenna 111, a second antenna 112, and an adjustment circuit 120. The first antenna 111 has a feeding end F11, and the feeding end F11 of the first antenna 111 is electrically connected to the signal source 101 through the adjusting circuit 120. The feeding end F12 of the second antenna 112 is electrically connected to the signal source 102.

In an embodiment, the first antenna 111 is operable in a low frequency band (eg, 699 MHz to 960 MHz). In addition, the second antenna 112 can operate in at least one frequency band. For example, the second antenna 112 can operate in an intermediate frequency band (eg, 1710 MHz to 2170 MHz) and a high frequency band (eg, 2500 MHz to 2690 MHz). Specifically, the first antenna 111 can receive or transmit electromagnetic waves in a low frequency band through a resonant mode. In addition, the second harmonic of the first antenna 111 in the resonant mode will be located in the intermediate frequency band of the second antenna 112, and the third harmonic of the first antenna 111 in the resonant mode It will be located in the high frequency band of the second antenna 112. In other words, the frequency band of the higher harmonics of the first antenna 111 overlaps with the frequency band operated by the second antenna 112.

In order to reduce the mutual influence between the first antenna 111 and the second antenna 112, when the second antenna 112 operates in at least one frequency band, the adjustment circuit 120 can adjust the operating frequency of the first antenna 111 in the resonant mode. Or, the impedance matching of the first antenna 111 in the resonant mode is adjusted. That is, the adjustment circuit 120 can adjust the return loss or the standing wave ratio of the first antenna 111 in the resonant mode. Thereby, the position of the higher harmonics of the first antenna can be adjusted, thereby contributing to reducing the influence of the first antenna 111 on the second antenna 112. For example, as the resonance mode of the first antenna 111 is adjusted, it is possible to prevent the higher harmonics of the first antenna 111 from affecting the signal to be received by the second antenna 112, thereby effectively improving the first day. The isolation between line 111 and second antenna 112.

Furthermore, the adjustment circuit 120 includes a switching unit 130 and a plurality of resonant elements 141-142. The switching unit 130 has first to fourth terminals P11 to P14. The first end P11 of the switching unit 130 is electrically connected to the feeding end F11 of the first antenna 111. The second end P12 of the switching unit 130 is electrically connected to the signal source 101. The third end P13 of the switching unit 130 is electrically connected to the resonant element 141. The fourth end P14 of the switching unit 130 is electrically connected to the signal source 101 and electrically connected to the ground through the resonant element 142. In addition, the resonant element 141 can be formed by an inductor L1, and the resonant element 142 can be formed by a capacitor C1.

In operation, the wireless communication device 100 can disable or enable the second antenna 112. When the second antenna 112 is in an enabled state, the second antenna 112 will be operable in at least one frequency band. For example, the signal source 102 can provide a feed signal to the feed end F12 of the second antenna 112, thereby causing the second antenna 112 to receive or transmit electromagnetic waves in the at least one frequency band. On the other hand, when the second antenna 112 is in the disabled state, the wireless communication device 100 will stop receiving or transmitting electromagnetic waves using the second antenna 112.

In the case of the first antenna 111, when the wireless communication device 100 disables the second antenna 112, the adjustment circuit 120 switches the first antenna 111 to the first mode. In addition, in the first mode, the first end P11 of the switching unit 130 is electrically connected to the second end P12, so that the adjusting circuit 120 can directly connect the feeding end F11 of the first antenna 111 to the signal source 101. In this way, when the first antenna 111 is in the first mode, the first antenna 111 will receive or emit electromagnetic waves through the resonant mode.

When the wireless communication device 100 enables the second antenna 112, that is, when the second antenna 112 operates in at least one frequency band, the adjustment circuit 120 switches the first antenna 111 to the second mode. In addition, in the second mode, the first end P11 of the switching unit 130 is electrically connected to the third end P13 or the fourth end P14, thereby causing the feeding end F11 of the first antenna 111 to be electrically connected to the multiple One of the resonant elements 141-142. In this way, when the first antenna 111 is in the second mode, the resonant element 141 or 142 in the adjusting circuit 120 can be used to adjust the impedance matching between the first antenna 111 and the signal source 101, thereby reducing the first The frequency band of the higher harmonics of the antenna 111 affects the operating frequency band of the second antenna 112 and helps to improve the isolation between the first antenna 111 and the second antenna 112.

For example, FIG. 2 is a graph of a return loss (S11) of a first antenna according to an embodiment of the present invention, and FIG. 3 is between a first antenna and a second antenna according to an embodiment of the invention. The isolation (S21) curve. The curves 210-230 in FIG. 2 are respectively used to indicate the return loss of the first antenna 111 when the first end P11 of the switching unit 130 is sequentially switched to the second end to the fourth end P12~P14. . In addition, the curves 310-330 in FIG. 3 are respectively used to indicate that when the first end P11 of the switching unit 130 is sequentially switched to the second end to the fourth end P12~P14, the first antenna 111 is enabled. The isolation factor between the second antennas 112.

As shown by the curve 210 in FIG. 2, when the first antenna 111 is maintained in the first mode, the first antenna 111 generates a resonant mode in a low frequency band (for example, 699 MHz to 960 MHz), and thus the first antenna 111 can Receiving or transmitting electromagnetic waves through the resonant mode. As shown by the curves 220 and 230 in FIG. 2, when the first antenna 111 is maintained in the second mode, the impedance matching of the resonant mode of the first antenna 111 is deteriorated, thereby reducing the high order of the first antenna. The effect of harmonics on the operating frequency band of the second antenna 112.

Moreover, as shown by the curve 310 in FIG. 3, if the second antenna 112 is enabled and the first antenna 111 is maintained in the first mode, between the first antenna 111 and the second antenna 112 The isolation will be very poor. As shown by curves 320 and 330 in FIG. 3, isolation between the first antenna 111 and the second antenna 112 is provided if the second antenna 112 is enabled and the first antenna 111 is maintained in the second mode. The degree will be greatly improved, and the radiation efficiency of the second antenna 112 can be greatly improved.

For example, FIG. 4 is a graph showing radiation efficiency of a second antenna according to an embodiment of the present invention. The curves 410 and 420 are respectively used to indicate the radiation efficiency of the second antenna 112 that is enabled when the first antenna 111 is switched to the first mode and the second mode, respectively. Looking at the curves 410 and 420, it can be seen that when the second antenna 112 is enabled, switching to the first antenna 111 of the second mode will greatly increase the radiation efficiency of the second antenna 112.

It is worth mentioning that the general knowledge in the field can be designed according to the Planar Inverted F Antenna (PIFA), monopole antenna, dipole antenna or A loop antenna is used to implement the first antenna 111. For example, FIG. 5 is a schematic diagram for explaining a first antenna and an adjustment circuit according to an embodiment of the invention. As shown in FIG. 5, the first antenna 111 in FIG. 1 is a planar inverted-F antenna, and the planar inverted-F antenna includes a radiating portion 501, a feeding portion 502, and a short-circuit portion 503. In addition, the feeding portion 502 can be configured to form the feeding end F11 of the first antenna 111, and the feeding portion 502 is electrically connected to the signal source 101 through the adjusting circuit 120.

It should be noted that although the embodiment of FIGS. 1 and 5 cites the arrangement position of the adjustment circuit, it is not intended to limit the present invention. For example, in another embodiment, the adjustment circuit 120 can also be disposed at the shorted end of the first antenna 111. Thereby, when the second antenna 112 operates in at least one frequency band, the adjustment circuit 120 can adjust the operating frequency of the first antenna 111 in the resonant mode. In this way, the frequency band of the higher harmonics of the first antenna 111 and the operating frequency band of the second antenna 112 may not overlap each other, so that the relationship between the first antenna 111 and the second antenna 112 can be effectively improved. Isolation.

For example, FIG. 6 is a schematic diagram for explaining a first antenna and an adjustment circuit according to another embodiment of the present invention. As shown in FIG. 6, the first antenna 611 is a planar inverted-F antenna, and the planar inverted-F antenna includes a radiating portion 601, a feeding portion 602, and a short-circuit portion 603. Further, the feeding portion 602 can be used to constitute the feeding end of the first antenna 611, and the short-circuit portion 603 can be used to constitute the short-circuiting end of the first antenna 611. Furthermore, the feeding portion 602 (ie, the feeding end) of the first antenna 611 is electrically connected to the signal source 610, and the short-circuit portion 603 (ie, the short-circuiting end) of the first antenna 611 is electrically transmitted through the adjusting circuit 620. Connect to ground.

Looking further, the adjustment circuit 620 includes a switching unit 630 and a plurality of resonant elements 641-642. The switching unit 630 has first to fourth terminals P61 to P64. The first end P61 of the switching unit 630 is electrically connected to the short-circuit portion 603 (ie, the short-circuit end) of the first antenna 611. The second end P62 of the switching unit 630 is electrically connected to the ground. The resonant element 641 is electrically connected between the third end P63 of the switching unit 630 and the ground. The resonant element 642 is electrically connected between the fourth end P64 of the switching unit 630 and the ground. In addition, the resonant element 641 can be formed by an inductor L6, and the resonant element 642 can be formed by a capacitor C6.

In operation, when the wireless communication device 100 disables the second antenna 112, the adjustment circuit 620 switches the first antenna 611 to the first mode. In addition, in the first mode, the first end P61 of the switching unit 630 is electrically connected to the second end P62, so that the adjusting circuit 620 can directly turn on the short-circuiting portion 603 (ie, the short-circuiting end) of the first antenna 611. To the ground. In this way, when the first antenna 611 is in the first mode, the first antenna 611 can receive or transmit electromagnetic waves in a low frequency band (for example, 699 MHz to 960 MHz) through a resonant mode.

When the wireless communication device 100 enables the second antenna 112, that is, when the second antenna 612 operates in at least one frequency band (for example, 1710 MHz to 2170 MHz and 2500 MHz to 2690 MHz), the adjustment circuit 620 will use the first antenna 611. Switch to the second mode. In addition, in the second mode, the first end P61 of the switching unit 630 is electrically connected to the third end P63 or the fourth end P64, thereby causing the short-circuit portion 603 of the first antenna 611 (ie, the short-circuit end) One of the plurality of resonant elements 641-642 is electrically connected to the ground. In this way, when the first antenna 611 is in the second mode, the resonant element 641 or 642 in the adjusting circuit 620 can be used to adjust the operating frequency of the first antenna 611 in the resonant mode, thereby effectively improving the The isolation between an antenna 611 and the second antenna 112.

For example, FIG. 7 is a graph of a return loss of a first antenna according to another embodiment of the present invention, and FIG. 8 is a diagram of a first antenna and a second antenna according to another embodiment of the present invention. Isolation curve. The curves 710-730 in FIG. 7 are respectively used to indicate that the first antenna P61 of the switching unit 630 is switched to its second end to the fourth end P62-P64, and the return loss of the first antenna 611 is respectively used. . In addition, the curves 810-830 of FIG. 8 are respectively used to indicate that when the first end P61 of the switching unit 630 is sequentially switched to the second end to the fourth end P62-P64, the first antenna 611 is enabled. An isolation graph between the second antennas 112.

As shown by the curves 710-730 in FIG. 7, when the first antenna 611 is switched from the first mode to the second mode, the operating frequency of the first antenna 611 in the resonant mode will be shifted to the high frequency. Further, the frequency band of the higher harmonics of the first antenna 111 and the frequency band operated by the second antenna 112 do not overlap each other. In addition, as shown by the curve 810 in FIG. 8, if the second antenna 112 is enabled (eg, the second antenna 112 operates at 1710 MHz to 2170 MHz and 2500 MHz to 2690 MHz), and the first antenna 611 is maintained at the first In the mode, the isolation between the first antenna 611 and the second antenna 112 will be very poor. Furthermore, as shown by the curves 820 and 830 in FIG. 8, if the second antenna 112 is enabled and the first antenna 611 is maintained in the second mode, the first antenna 611 and the second antenna 112 are The isolation between the two will be greatly improved, and the radiation efficiency of the second antenna 112 can be greatly improved.

It is worth mentioning that although the above embodiments exemplify the operating frequency bands of the first antenna and the second antenna, they are not intended to limit the present invention. For example, in another embodiment, the first antenna 111 or 611 can receive or transmit through a resonant mode in a low frequency band (eg, 699 MHz to 960 MHz) and an intermediate frequency band (eg, 1710 MHz to 2170 MHz). Electromagnetic waves. That is, the first antenna 111 or 611 can operate in the low frequency band and the intermediate frequency band through the resonant mode. In addition, the second antenna 112 can operate in a high frequency band (eg, 2500 MHz to 2690 MHz). At this time, the second harmonic of the first antenna 111 or 611 in the resonant mode will be located in the high frequency band of the second antenna 112. Further, as shown in FIG. 1, the adjustment circuit 120 may be provided at the feed end F11 of the first antenna 111. Alternatively, as shown in FIG. 6, an adjustment circuit 620 may be disposed at the ground end of the first antenna 611. Thereby, the interaction between the first antenna and the second antenna is reduced by the adjustment circuit, thereby helping to improve the isolation between the two antennas.

In summary, the wireless communication device of the present invention includes a first antenna and a second antenna, and the frequency band of the higher harmonics of the first antenna in a resonant mode and the frequency band operated by the second antenna are mutually overlapping. In addition, when the second antenna operates in at least one frequency band, the adjusting circuit adjusts a return loss of the first antenna in the resonant mode to reduce electromagnetic waves that can be received or emitted by the first antenna. energy. Or, when the second antenna operates in the at least one frequency band, the adjusting circuit adjusts an operating frequency of the first antenna in a resonant mode, so that the frequency band of the first antenna and the second day of the second antenna The frequency bands operated by the lines do not overlap each other. Thereby, the isolation between the first antenna and the second antenna can be increased, thereby contributing to an increase in the receiving quality of the wireless communication device.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100: wireless communication device 111, 611: first antenna 112: second antenna 120, 620: adjustment circuit 130, 630: switching unit P11, P61: first end P12, P62 of the switching unit: second of the switching unit Terminals P13, P63: third terminals P14, P64 of the switching unit: fourth ends 141~142, 641~642 of the switching unit: resonant elements F11, F12: feeding ends 101, 102, 610: signal sources L1, L6: Inductors C1, C6: Capacitors 210~230, 310~330, 410, 420, 710~730, 810~830: Curves 501, 601: Radiations 502, 602: Feeding parts 503, 603: Short circuit

1 is a schematic diagram of a wireless communication device in accordance with an embodiment of the present invention. 2 is a graph showing a return loss curve of a first antenna according to an embodiment of the present invention. 3 is a graph showing the isolation between a first antenna and a second antenna in accordance with an embodiment of the present invention. 4 is a graph showing radiation efficiency of a second antenna in accordance with an embodiment of the present invention. FIG. 5 is a schematic diagram for explaining a first antenna and an adjustment circuit according to an embodiment of the invention. FIG. 6 is a schematic diagram for explaining a first antenna and an adjustment circuit according to another embodiment of the present invention. FIG. 7 is a graph showing a return loss curve of a first antenna according to another embodiment of the present invention. FIG. 8 is a graph showing isolation between a first antenna and a second antenna according to another embodiment of the present invention.

100: wireless communication device 111: first antenna 112: second antenna 120: adjustment circuit 130: switching unit P11: first end P12 of the switching unit: second end P13 of the switching unit: third end P14 of the switching unit : fourth end 141~142 of switching unit: resonant element F11, F12: feeding end 101, 102: signal source L1: inductance C1: capacitance

Claims (9)

A wireless communication device comprising: a first antenna receiving or transmitting an electromagnetic wave through a resonant mode; and a second antenna operating in at least one frequency band, wherein the resonant mode of the first antenna At least one harmonic bit is in the at least one frequency band; and an adjusting circuit electrically connected to the first antenna, wherein the adjusting circuit adjusts the first when the second antenna operates in the at least one frequency band An operating frequency of the antenna in the resonant mode or an impedance matching of the first antenna in the resonant mode, wherein the adjusting circuit is to be the first when the wireless communication device disables the second antenna Switching the antenna to a first mode, such that the first antenna receives or transmits the electromagnetic wave through the resonant mode, and when the wireless communication device enables the second antenna, the adjusting circuit turns the first The antenna is switched to a second mode to adjust an operating frequency of the first antenna in the resonant mode or to adjust impedance matching of the first antenna in the resonant mode. The wireless communication device of claim 1, wherein the first antenna has a feed end, and when the first antenna is in the first mode, the adjusting circuit directly directly connects the first antenna The feed end is electrically connected to a signal source, and when the first antenna is in the second mode, the feed end of the first antenna is electrically connected to one of the plurality of resonant elements in the adjustment circuit. The wireless communication device of claim 2, wherein the resonant components comprise an inductor and a capacitor, and the adjusting circuit further comprises: a switching unit having a first end electrically connected to the feeding end, Electrically connecting a second end of the signal source, a third end electrically connected to the inductor, and a fourth end electrically connected to the capacitor, wherein when the first antenna is in the first mode, the The first end of the switching unit is electrically connected to the second end. When the first antenna is in the second mode, the first end of the switching unit is electrically connected to the third end or the fourth end. The wireless communication device of claim 3, wherein the inductor is electrically connected between the third end of the switching unit and the signal source, and the fourth end of the switching unit is electrically connected to the signal The source is electrically connected to a ground through the capacitor. The wireless communication device of claim 1, wherein the first antenna has a feed end and a short circuit end, and when the first antenna is in the first mode, the adjusting circuit directly The short-circuiting end of an antenna is electrically connected to a grounding end. When the first antenna is in the second mode, the short-circuiting end of the first antenna transmits an electrical property of the plurality of resonant components in the adjusting circuit Connect to this ground. The wireless communication device of claim 5, wherein the resonant components comprise an inductor and a capacitor, and the adjusting circuit further comprises: a switching unit having a first end electrically connected to the shorting end, and Connecting a second end, a third end, and a fourth end of the grounding end, the inductor is electrically connected between the third end of the switching unit and the ground end, and the capacitor is electrically connected to the Between the fourth end of the switching unit and the ground, wherein the first end of the switching unit is electrically connected to the second end when the first antenna is in the first mode, when the first When the antenna is in the second mode, the first end of the switching unit is electrically connected to the third end or the fourth end. The wireless communication device of claim 1, wherein the first antenna operates in a low frequency band through the resonant mode, and the at least one frequency band of the second antenna includes an intermediate frequency band and a high frequency. a frequency band, and the second harmonic and the third harmonic of the at least one harmonic are respectively located in the intermediate frequency band and the high frequency band. The wireless communication device of claim 1, wherein the first antenna is operated in a low frequency band and an intermediate frequency band through the resonant mode, and the at least one frequency band of the second antenna comprises a high frequency a frequency band, and a second harmonic of the at least one harmonic is in the high frequency band. The wireless communication device of claim 1, wherein the first antenna is a planar inverted F antenna, a monopole antenna, a dipole antenna or a loop antenna.