TW201401644A - Wideband antenna and wireless communication device - Google Patents

Abstract

A wideband antenna for a mobile device including a metal frame is disclosed. The wideband antenna includes a radiator for radiating a radio-frequency signal, a fix point that the radiator is coupled to a ground via the fix point, a feed-in element electrically connected between the radiator and the ground for feeding the radio-frequency signal to the radiator, and a parasitic radiator electrically connected to the ground and belonging to a part of the metal frame, wherein a distance between the radiator and the parasitic radiator induces a coupling effect to form a coupling antenna to perform radio-frequency signal transmission and reception.

Description

Broadband antenna and wireless communication device

The invention relates to a broadband antenna and a wireless communication device, in particular to a broadband antenna and a wireless communication device which can use the metal frame as a parasitic radiator to increase the operation bandwidth and conform to the product mechanism.

The antenna is used to transmit or receive radio waves to transmit or exchange radio signals. Electronic products with wireless communication functions, such as notebook computers, personal digital assistants, etc., usually access the wireless network through built-in antennas. With the evolution of wireless communication technology, the operating frequencies of different wireless communication systems may be different. Therefore, an ideal antenna should cover the frequency bands required by different wireless communication networks with a single antenna.

Most of today's portable wireless communication devices are designed with aesthetics, durability, etc., often using metal casings or frames, so when the antenna is integrated into a portable wireless communication device, the antenna gain is often reduced or unstable. . In this case, in addition to the challenges faced by the antenna designer, the antenna designer needs to consider the integration with the metal frame. For example, how to design an antenna supporting the Long Term Evolution (LTE) band (704MHz to 960MHz and 1710MHz to 2700MHz) in a metal frame environment is difficult.

Therefore, how to combine the antenna with the metal frame environment, designing a broadband antenna with broadband characteristics, and satisfying the space limitation of the wireless communication device has become one of the goals of the industry.

Accordingly, it is a primary object of the present invention to provide a wideband antenna that has broadband characteristics and that satisfies the space limitations of wireless communication devices.

The invention discloses a broadband antenna for a wireless communication device including a metal frame, comprising a radiator for transmitting and receiving an RF signal; and a fixed point, the radiator is coupled to a ground via the fixed point; a feed element electrically connected between the radiator and the ground portion for feeding the RF signal to the radiator; and a parasitic radiator electrically connected to the ground portion, the parasitic radiator and The radiator is separated by a first distance, the parasitic radiation system is a part of the metal frame; wherein the first distance causes the parasitic radiator to couple with the radiator to form a coupled antenna for transmitting and receiving the RF signal.

The invention further discloses a wireless communication device, comprising a metal frame; and at least one antenna, each antenna comprising: a radiator for transmitting and receiving an RF signal; and a fixed point, the radiator being coupled via the fixed point a signal feeding portion electrically connected between the radiator and the ground portion for feeding the RF signal to the radiator; and a parasitic radiator electrically connected to the ground portion The parasitic radiator is spaced apart from the radiator by a first distance, and the parasitic radiation system is a part of the metal frame And the first distance causes the parasitic radiator to couple with the radiator to form a coupled antenna for transmitting and receiving the RF signal.

Please refer to FIG. 1 , which is a schematic diagram of a wireless communication device MS according to an embodiment of the present invention. The wireless communication device MS is externally covered with a casing 100, and includes a plurality of broadband antennas ANT_1, ANT_2 and ANT_3 for transmitting and receiving wireless signals or for multi-in multi-out (MIMO). Communication technologies are used to increase the throughput of wireless transmissions (Throughput). For convenience of explanation, the wireless communication device MS is a notebook computer, but is not limited thereto. The wireless communication device MS can also be a tablet computer, a mobile phone, a personal digital assistant or any electronic device with wireless communication function. As shown in FIG. 1, the wideband antennas ANT_1 and ANT_2 are disposed above the display of the wireless communication device MS, and the wideband antenna ANT_3 is disposed on the side of the keyboard of the wireless communication device MS.

In detail, please refer to FIG. 2, and FIG. 2 is a schematic structural view of the broadband antennas ANT_1 and ANT_2 of FIG. The broadband antenna ANT_1 includes a fixed point P, a grounding portion 200, a radiator 20, a signal feeding end 210, and a parasitic radiator 212. The grounding portion 200 is used to provide grounding. The signal feeding end 210 is electrically connected between the radiator 20 and the grounding portion 200 for feeding the RF signal RF_1 to the radiator 20. The radiator 20 is electrically connected to the signal feeding end 210 and coupled to the grounding portion 200 by a fixed point P for transmitting and receiving an RF signal RF_1. The parasitic radiator 212 is electrically connected to the ground portion 200, and the parasitic radiator 212 is spaced apart from the radiator 20 by a distance D1, so that the parasitic antenna The emitter 212 and the radiator 20 are coupled. Therefore, the broadband antenna ANT_1 forms a coupled antenna structure, which can be used to transmit and receive the RF signal RF_1 to achieve wireless communication.

Specifically, when the RF signal RF_1 is fed into the radiator 20, a current path is generated on the radiator 20, and a coupling between the parasitic radiator 212 and the radiator 20 forms a coupling on the parasitic radiator 212. The current path is returned to the ground portion 200. The length of the coupled current path extending from the parasitic radiator 212 to the ground portion 200 is long, so that a resonant mode of the low frequency band can be excited for transmitting and receiving the RF signal RF_1 in the low frequency band. Moreover, by adjusting the size of the distance D1, the equivalent inductance or equivalent capacitance between the radiator 20 and the parasitic radiator 212 can be changed, and the radiation band and bandwidth of the broadband antenna ANT_1 can be adjusted to design a desired match. With resonance mode.

It should be noted that the broadband antenna ANT_1 is designed in accordance with the appearance of the wireless communication device MS. The housing 100 of the wireless communication device MS includes a metal frame 23, and the parasitic radiator 212 is part of the metal frame 23, The wideband antenna ANT_1 can be subtly integrated into the appearance of the wireless communication device. In other words, the broadband antenna ANT_1 in the form of a coupling not only simply designs the radiator 20 but covers an antenna form of the structure of the integral ground portion 200, the structure of the ground portion 200, the parasitic radiator 212, and the metal frame 23 Design is a factor that affects antenna characteristics.

As shown in FIG. 2, the metal frame 23 includes a gap 231 whose position depends on the length L1 of the parasitic radiator 212, wherein the length L1 is The length of the pitch 231 is extended by the parasitic radiator 212 corresponding to the fixed point P. Preferably, the length L is substantially equal to a quarter wavelength of the RF signal RF_1 in the low frequency band, so that the broadband antenna ANT_1 has a better match in the low frequency band.

Please note that the present invention mainly utilizes the metal frame 23 as the parasitic radiator 212 of the broadband antenna ANT_1, and then transmits the coupling between the radiator 20 and the parasitic radiator 212 to excite different resonant modes, so that the broadband antenna ANT_1 It is operable in different frequency bands F1, F2, F3 and therefore has a good bandwidth. In addition, the broadband antenna ANT_1 is designed in accordance with the appearance of the wireless communication device MS, and a part of the metal frame 23, that is, the parasitic radiator 212, is one of the radiators of the broadband antenna ANT_1, so the broadband antenna ANT_1 can be ingeniously Integrate the appearance of the wireless communication device.

On the other hand, the wireless communication device MS includes a broadband antenna ANT_2 for transmitting and receiving the RF signal RF_2. In this architecture, the metal frame 23 correspondingly includes the spacing 232. The broadband antennas ANT_1 and ANT_2 are different in that the relative positions of the two are different from the spacings 231 and 232, that is, the spacing 231 is located in the broadband antenna ANT_1 to -X. The position of the direction, and the spacing 232 is located in the +X direction of the broadband antenna ANT_2. In this way, the designer can adjust the relative positions of the broadband antennas ANT_1, ANT_2 and the spacings 231, 232 according to actual needs, so as to increase the design flexibility of the broadband antenna.

Please refer to FIG. 3A and FIG. 3B. FIG. 3A and FIG. 3B are respectively a schematic diagram of a voltage standing wave ratio (VSWR) and a radiation gain of the broadband antenna ANT_1. As shown in Figure 3A, the broadband antenna ANT_1 is at low frequency. The voltage standing wave ratio with F1 (704MHz~960MHz) is less than 3.5, and the voltage standing wave ratio in the high frequency band F2 (1710MHz~2170MHz) is less than 2, and the voltage standing wave ratio in the high frequency band F3 (2300MHz~2700MHz) It is roughly less than 2. As shown in FIG. 3B, the radiation gain of the broadband antenna ANT_1 in the low frequency band F1 is greater than -4 dB, the radiation gain in the high frequency band F2 is substantially greater than -4 dB, and the radiation gain in the high frequency band F3 is substantially greater than -4.5 dB.

It can be seen that the wideband antenna ANT_1 can operate in different frequency bands F1, F2, and F3, and therefore has a good bandwidth to be applied to communication bands required by different communication technologies, such as Long Term Evolution (LTE), Operating Bands such as Wireless Wide Area Network (WWAN), Wireless Local Area Network (WLAN), and Worldwide Interoperability for Microwave Access (WIMAX).

Furthermore, the wideband antenna ANT_1 has a good antenna performance and a considerable degree of tolerance for environmental changes. In the first figure, the broadband antenna ANT_3 and the broadband antenna ANT_1 have the same antenna pattern, the difference between the two is that the position of the transmission is different, that is, the broadband antenna ANT_1 is disposed above the display of the wireless communication device MS, and the broadband antenna The ANT_3 is disposed on the side of the keyboard of the wireless communication device MS. Please refer to FIG. 4A and FIG. 4B. FIG. 4A and FIG. 4B are schematic diagrams showing the voltage standing wave ratio and the radiation gain of the broadband antenna ANT_3, respectively. As shown in Fig. 4A, the voltage standing wave ratio of the wideband antenna ANT_3 in the low frequency band F1 (704 MHz to 960 MHz) is less than 4, and the voltage standing wave ratio in the high frequency band F2 (1710 MHz to 2170 MHz) Below 4.5, the voltage standing wave ratio in the high frequency band F3 (2300 MHz to 2700 MHz) is substantially less than 4. As shown in FIG. 4B, the broadband antenna ANT_3 has a radiation gain of about -4 dB at 824 MHz to 960 MHz, and a radiation gain of about -4 dB at 1850 MHz to 1990 MHz. Therefore, the wideband antenna ANT_3 can have a considerable degree of antenna performance even if the placement position is different.

In addition, please refer to FIG. 5A to FIG. 5C, and FIG. 5A to FIG. 5C respectively illustrate a top view, an isometric view and a bottom view of the wireless communication device MS applied to the broadband antenna ANT_5. FIG. 5A illustrates an embodiment of the detailed structure of the broadband antenna ANT_5. The radiator 50 of the broadband antenna ANT_5 includes radiating portions 51 and 52. The radiator 50 is electrically connected to the fixed point P through the radiating portion 52, thereby electrically It is connected to the grounding portion 500, wherein the connecting portion can electrically connect the radiating portion 52 and the grounding portion 500 by using a fixing member such as a screw or a conductive foam. The radiation portion 51 is spaced apart from the radiation portion 52 by a distance D2 which causes the radiation portion 51 to couple with the radiation portion 52. The radiation portion 52 is spaced apart from the parasitic radiator 512 by a distance D1 which causes the radiation portion 52 to couple with the parasitic radiator 512. When the RF signal RF_1 is fed into the radiator 50, a current path is generated on the radiation portion 51, and a coupling current path is formed on the radiation portion 52 to return to the ground portion by the coupling between the radiation portion 51 and the radiation portion 52. 500, and a coupling current path is also generated on the parasitic radiator 512 to return to the ground portion 500. The radiating portion 52 has a length L2 in which the length L2 extends from the radiating portion 52 to the end of the radiating portion 52 corresponding to the fixed point P. Preferably, the length L2 is substantially equal to a quarter wavelength of the RF signal RF_1 in the frequency band F1, so the radiation portion 52 can also be used to receive the RF signal RF_1 of the frequency band F1.

In detail, the radiating portion 51 includes the arms RAD_1, RAD_2, and the arm RAD_1 extends from the signal feeding end 210 in the +X direction for transmitting and receiving the RF signal RF_1 in the frequency band F2, and the arm RAD_2 is connected to the signal feeding terminal 210. Extending in the -X direction, it is used to transmit and receive the RF signal RF_1 in the frequency band F3. In this way, the broadband antenna ANT_1 can operate in the different frequency bands F1, F2, and F3, and thus has a good bandwidth. In addition, the lengths of the arms RAD_1 and RAD_2 in the +X direction and the -X direction can be adjusted accordingly according to actual applications to change the operating bands F2 and F3 of the arms RAD_1 and RAD_2.

In addition, the manner of fabricating the radiator 50 of the broadband antenna ANT_5 is not limited, for example, printing the radiation portions 51, 52 on an FR-4 glass fiber substrate, or molding a plastic piece through a mold. Further, the radiation portions 51 and 52 are fixed to the plastic member by a technique such as stamping, and the radiation portions 51 and 52 may be formed on the plastic member by a technique such as Laser Direct Structuring (LDS).

In summary, the present invention mainly utilizes a metal frame as a parasitic radiator of a broadband antenna, and then transmits a coupling between the radiator and the parasitic radiator or a plurality of radiators to excite different resonance modes to make the broadband antenna. It can operate in different frequency bands and therefore has good bandwidth. In addition, the broadband antenna is designed with the appearance of the wireless communication device, and a part of the metal frame is used as one of the radiators of the broadband antenna, so that the broadband antenna can be skillfully integrated into the appearance of the wireless communication device, thereby achieving Broadband effects and compliance with product organizations.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

MS‧‧‧Wireless communication device

100‧‧‧shell

ANT_1, ANT_2, ANT_3, ANT_5‧‧‧ wideband antenna

200, 500‧‧‧ Grounding Department

20, 50‧‧‧ radiator

51, 52‧‧‧ Department of Radiation

210‧‧‧ signal feed end

212, 512‧‧‧ Parasitic radiator

D1, D2‧‧‧ distance

L1, L2‧‧‧ length

23, 53‧‧‧ metal frame

231, 232, 531‧‧ ‧ spacing

RF_1, RF_2‧‧‧ RF signals

RAD_1, RAD_2‧‧‧ arms

+X, -X‧‧ Direction

P‧‧‧ fixed point

F1, F2, F3‧‧‧ bands

FIG. 1 is a schematic diagram of a wireless communication device according to an embodiment of the present invention.

Fig. 2 is a schematic view showing the structure of the wideband antenna of Fig. 1.

3A and 3B are schematic diagrams showing the voltage standing wave ratio and the radiation gain of the wideband antenna of Fig. 1, respectively.

4A and 4B are schematic diagrams showing the voltage standing wave ratio and the radiation gain when the broadband antenna of Fig. 1 is placed at another position.

5A to 5C are respectively a top view, an isometric view, and a bottom view of a wireless communication device applied to a wireless communication device.

ANT_1, ANT_2‧‧‧ wideband antenna

200‧‧‧ Grounding Department

20‧‧‧ radiator

210‧‧‧ signal feed end

212‧‧‧ Parasitic radiator

D1‧‧‧ distance

L1‧‧‧ length

23‧‧‧Metal frame

231, 232‧‧‧ spacing

RF_1, RF_2‧‧‧ RF signals

P‧‧‧ fixed point

+X, -X‧‧ Direction

Claims (24)

A broadband antenna for a wireless communication device including a metal frame, comprising: a radiator for transmitting and receiving an RF signal; and a fixed point, the radiator coupled to a ground portion via the fixed point; a signal feed end electrically connected between the radiator and the ground portion for feeding the RF signal to the radiator; and a parasitic radiator electrically connected to the ground portion, the parasitic radiator and The radiator is separated by a first distance, the parasitic radiation system is a part of the metal frame; wherein the first distance causes the parasitic radiator to couple with the radiator to form a coupled antenna for transmitting and receiving the RF signal. The broadband antenna of claim 1, wherein the wireless communication device comprises a housing, the metal frame being part of the housing. The wideband antenna of claim 2, wherein the ground portion is part of the housing for providing grounding. The broadband antenna of claim 1, wherein the metal frame comprises a pitch. The broadband antenna of claim 4, wherein the parasitic radiator has a first length, the first length being extended by the parasitic radiator corresponding to the fixed point The length of the spacing. The broadband antenna of claim 5, wherein the parasitic radiator is configured to transmit and receive a radio frequency signal of a first frequency band. The wideband antenna of claim 6, wherein the first length is substantially equal to one quarter of a wavelength of the radio frequency signal of the first frequency band. The wideband antenna of claim 1, wherein the radiator includes a first radiating portion, and the radiating body is electrically connected to the signal feeding end through the first radiating portion. The broadband antenna of claim 8, wherein the radiator includes a second radiating portion, the radiating body is electrically connected to the fixed point through the second radiating portion, thereby being electrically connected to the ground portion, the first The radiation portion is spaced apart from the second radiation portion by a second distance, the second distance causing the first radiation portion to couple with the second radiation portion. The broadband antenna of claim 9, wherein the second radiating portion has a second length, and the second length extends from the second radiating portion to the end of the second radiating portion corresponding to the fixed point. The broadband antenna of claim 10, wherein the second radiating portion is configured to receive a radio frequency signal of a first frequency band, the second length being substantially equal to the radio frequency signal of the first frequency band One of the quarter wavelengths. The broadband antenna of claim 8, wherein the first radiating portion comprises: a first arm extending from the signal feeding end in a first direction for transmitting and receiving a radio frequency signal of a second frequency band; The second arm extends from the signal feeding end in a second direction for transmitting and receiving a third frequency band radio frequency signal; wherein the first direction is opposite to the second direction. A wireless communication device includes: a metal outer frame; and at least one antenna, each antenna includes: a radiator for transmitting and receiving an RF signal; and a fixed point, the radiator is coupled to the fixed point via the fixed point a grounding portion; a signal feeding end electrically connected between the radiator and the ground portion for feeding the RF signal to the radiator; and a parasitic radiator electrically connected to the ground portion, The parasitic radiator is spaced apart from the radiator by a first distance, the parasitic radiation system being part of the metal frame; wherein the first distance causes the parasitic radiator to couple with the radiator to form a coupled antenna, Used to send and receive the RF signal. The wireless communication device of claim 13, further comprising a housing, the metal The outer frame is part of the housing. The wireless communication device of claim 14, wherein the ground portion is part of the housing for providing ground. The wireless communication device of claim 13, wherein the metal frame comprises a pitch. The wireless communication device of claim 16, wherein the parasitic radiator has a first length, the first length being extended by the parasitic radiator to the length of the pitch corresponding to the fixed point. The wireless communication device of claim 17, wherein the parasitic radiator is configured to transmit and receive a radio frequency signal of a first frequency band. The wireless communication device of claim 18, wherein the first length is substantially equal to one quarter of a wavelength of the RF signal of the first frequency band. The wireless communication device of claim 13, wherein the radiator comprises a first radiating portion, and the radiating body is electrically connected to the signal feeding end through the first radiating portion. The wireless communication device of claim 20, wherein the radiator comprises a second radiating portion, and the radiating body is electrically connected to the fixed point through the second radiating portion, And electrically connected to the grounding portion, the first radiating portion is spaced apart from the second radiating portion by a second distance, and the second distance causes the first radiating portion to couple with the second radiating portion. The wireless communication device of claim 21, wherein the second radiating portion has a second length, the second length extending from the second radiating portion to the end of the second radiating portion corresponding to the fixed point. The wireless communication device of claim 22, wherein the second radiating portion is configured to receive a radio frequency signal of a first frequency band, the second length being substantially equal to one quarter wavelength of the radio frequency signal of the first frequency band. The wireless communication device of claim 20, wherein the first radiating portion comprises: a first arm extending from the signal feeding end in a first direction for transmitting and receiving a radio frequency signal of a second frequency band; a second arm extending from the signal feed end in a second direction for transmitting and receiving a third frequency band radio frequency signal; wherein the first direction is opposite to the second direction.