CN107369892B - A multi-frequency terminal antenna for all-metal casing - Google Patents

Abstract

The present invention provides a kind of multifrequency terminal antenna for full metal jacket, belongs to antenna technical field.Inventive antenna includes the metal shell for being installed in circuit system back, is arranged in the positive feeding network of system circuit board and gap；The metal shell is located at circuit system back and offers dual-end type gap and single-ended open-type gap respectively thereon, and the feed branch to match in feeding network with feed port across above-mentioned two gap, motivates gap to form multiple frequency point resonance respectively.The present invention further loads on the improvement in dual-end type gap by U-shaped folded metal piece, forms the three-dimensional structure for being different from existing two-dimensional aperture antenna to cover more multiband；The present invention is realizing multiband and wide band while also solving the problems, such as that the metal shell of antenna and large area coexists causes antenna performance impaired, improves the intensity, texture and aesthetic feeling of terminal device.

Description

A multi-frequency terminal antenna for all-metal casing

technical field

The invention belongs to the technical field of antennas, and in particular relates to a multi-frequency terminal antenna used in an all-metal casing.

Background technique

With the advent of the information age, mobile communication has achieved unprecedented development. As an important part of wireless communication, the antenna determines the electrical performance of the terminal equipment to communicate with the outside world. Generally speaking, a good antenna should significantly improve the overall performance of the terminal equipment while effectively reducing the space occupied by the antenna. The signal strength and rate of data communication obtained by the end device. Facing the development of mobile communication networks, 4G communication networks that support high-speed data transmission are being fully popularized, and research on 5G communication networks, which are an upgraded version of 4G communication networks, is also in full swing. Therefore, 4G, 5G and WLAN are integrated. The integrated 4G/5G/WLAN communication network is the development trend of wireless communication in the future, which requires terminal devices to meet all frequency bands of WLAN, 4G and 5G communication networks, and at the same time to be as backward compatible as possible The frequency band of the 3G communication network. And such a wide frequency band coverage is a big problem for the design of the terminal equipment antenna. In addition, with the development of technology, metal casings are gradually appearing in communication terminal products. To a large extent, the metal casing can enhance the structural strength of the communication terminal device and meet the needs of consumers for aesthetic and tactile sensations. However, the antennas of the communication terminal equipment have changed from the initial external antenna to the built-in antenna to the full metal shell antenna. The appearance of the product is more and more beautiful, but the area left for the antenna to radiate is getting smaller and smaller. Therefore, the metal shell often seriously affects the radiation performance of the terminal antenna. As an important part of the communication system, the performance of the antenna directly affects the performance of the terminal equipment. Therefore, how to solve the problem of the coexistence of the antenna and the large-area metal casing has always been a difficulty that needs to be overcome in the art.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a terminal antenna covering the frequency bands of 5G, 4G and WLAN communication networks, and simultaneously solve the problem of coexistence of the antenna and a large-area metal casing.

In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions:

technical solution one;

A multi-frequency antenna for an all-metal casing, comprising a metal casing installed on the back of a system circuit board, a slot opened on the metal casing, and a feeding network disposed on the front of the system circuit board; it is characterized in that:

A metal frame extending from the back of the system circuit board to the side is arranged on the surrounding edges of the metal shell; a first slot and a second slot are opened on the metal shell, and the first slot is a double-ended opening type slot, The second slit is a single-ended open slit; the first slit and the second slit divide the metal frame into three independent sections;

The feeding network includes: a feeding branch, a matching circuit and a feeding port; a matching circuit is connected between the feeding port and the corresponding feeding branch, and the feeding branch straddles the first gap and the first gap on the back of the system circuit board respectively. Two gaps.

technical solution two;

A multi-frequency intelligent terminal antenna used for an all-metal casing, comprising a metal casing installed on the back of a system circuit board, a slot opened on the metal casing, and a feeding network disposed on the front of the system circuit board; it is characterized in that:

A metal frame extending from the back of the system circuit board to the side is arranged on the surrounding edges of the metal shell; a first slot and a second slot are opened on the metal shell, and the first slot is a double-ended opening type slot , the second slot is a single-ended open slot, and the first slot and the second slot divide the metal frame into three independent sections;

The feeding network includes: a feeding branch, a matching circuit, a feeding port and a gating circuit; a gating circuit is connected between the feeding port and the feeding branch, and a gating circuit is connected between each feeding branch and the gating circuit. The matching circuit, and the feeding branches respectively span the first slot and the second slot on the back of the system circuit board.

According to the embodiment of the present invention, the gating circuit in the present invention includes: a gating switch, a comparison control circuit and a detection circuit.

The second technical solution is to integrate the function of antenna frequency reconstruction on the basis of the first technical solution, so as to realize intelligent judgment and select different working frequency bands of the antenna.

Further, in the above two technical solutions, the metal frame includes two long sides and two short sides arranged oppositely, and the two second short sides are oppositely arranged and connected between the two long sides; The first slit and the second slit are arranged close to the short side of the metal frame.

Further, in the above two technical solutions, the system circuit board is a dielectric substrate or a single-sided copper-clad dielectric substrate.

Further, the width of the slit on the metal shell is between 0.5 mm and 5 mm.

Further, in the above two technical solutions, the distance between the gap on the metal shell and the short side thereof is adjustable.

Further, in the above two technical solutions, the opening width of the slot is the same as or different from the width of the slot, and the opening width of the slot is between 0.5 mm and 5 mm.

Further, in the above two technical solutions, a U-shaped folded metal sheet 300 which is loaded on the first slit to separate it into a single-ended open slit is also included.

Further, the U-shaped folded metal sheet and the system circuit board are arranged in isolation from each other.

According to the embodiment of the present invention, in the present invention, the U-shaped folded metal sheet is partially suspended above the front of the system circuit board, and the two ends of the U-shaped folded metal sheet penetrate downward into the system circuit board and are connected to the metal shell on the back thereof, so that the U-shaped folded metal sheet is The folded metal sheet separates the first slit to form a single-ended open slit.

Wherein: the length and width of the single-ended open-type slit formed by the first slit and the U-shaped folded metal sheet loaded thereon can be adjusted.

As a specific embodiment of the present invention, a non-metallic material may also be filled between the part of the suspended U-shaped folded metal sheet and the system circuit board below it.

Further, in the above two technical solutions, the metal casing is used as the system ground.

Compared with the prior art, the beneficial effects of the present invention are:

1. In the present invention, by loading a double-ended open slot on the metal shell, the mechanism of the double-ended open slot to form resonance is similar to that of the existing single-ended open slot. There are single-ended open-type slits, which can form a near-short-circuit working state near the feeding position, which is equivalent to two single-ended open-type slits excited by the same feeding point; and different virtual short-circuit positions correspond to different frequencies, making double-ended open-ended slits The type slot forms multiple frequency resonances, thereby realizing multi-band operation. According to the results of the embodiments of the present invention, some 4G frequency bands and 5G frequency bands can be covered by adjusting parameters reasonably.

2. The present invention adopts the metal casing as the system ground, and the slot on the metal casing serves as the radiation unit. The present invention adopts a three-dimensional structure design, which is different from the traditional planar antenna structure. The coexistence of the metal casings leads to the problem that the performance of the antenna is impaired.

3. The antenna of the present invention is suitable for terminal equipment with an all-metal casing. Except for the two slits on the metal back cover and the two opening slits on the metal frame of the terminal equipment using the antenna of the present invention, the back and sides of the terminal equipment are made of metal. , which improves the strength, texture and aesthetics of terminal equipment to meet market demand.

Description of drawings

1 is a three-dimensional schematic diagram of a multi-frequency terminal antenna for an all-metal casing provided by an embodiment of the present invention;

2 is a schematic side view of a multi-frequency terminal antenna for an all-metal casing provided by an embodiment of the present invention;

3 is a schematic top view of a multi-frequency terminal antenna for an all-metal casing provided by an embodiment of the present invention;

4 is a schematic structural diagram of a metal back cover in a multi-frequency terminal antenna provided by an embodiment of the present invention;

5 is a schematic structural diagram of a feeding network located on the front of a system circuit board in a multi-frequency terminal antenna provided by an embodiment of the present invention;

6 is a schematic diagram of a U-shaped folded metal sheet and a system circuit board loaded on a first slot in a multi-frequency terminal antenna provided by an embodiment of the present invention;

7 is a schematic diagram of a matching circuit in a multi-frequency terminal antenna provided by an embodiment of the present invention;

8 is a schematic diagram of a gating circuit in a multi-frequency terminal antenna provided by an embodiment of the present invention;

9 is a working block diagram of a gating circuit in a multi-frequency terminal antenna provided by an embodiment of the present invention;

10 is a reflection coefficient curve of a multi-frequency terminal antenna provided in an embodiment of the present invention under two working states;

FIG. 11 is an efficiency curve of a multi-frequency terminal antenna provided in an embodiment of the present invention in two working states.

In the figure: 100 is the metal shell, 101 is the metal back cover, 102 is the metal frame, 200 is the slit, 201 is the first slit, 202 is the second slit, 300 is the U-shaped folded metal sheet, 400 is the feed port, 500 is the gating circuit, 601 is the feeding branch 1, 602 is the feeding branch 2, 701 is the matching circuit 1, 702 is the matching circuit 2, 800 is the system circuit board, and 900 is the feeding network.

Detailed ways

The gist of the present invention is to provide an antenna form loaded with a double-ended open slot, forming multiple frequency resonances through the slot antenna, thereby realizing multi-frequency band operation, and can be used for mobile terminals in future 5G communication networks; at the same time, the present invention adopts The all-metal shell design eliminates the shielding effect of the traditional metal shell on the antenna, and the antenna has excellent performance, realizing an antenna device suitable for all-metal shell terminal equipment.

The principles and characteristics of the present invention will be described in detail below in conjunction with specific embodiments and the accompanying drawings:

Example:

The terminal device in the present invention includes, but is not limited to, a mobile phone terminal, a smart watch, a portable computer or any similar terminal device.

With reference to the schematic diagrams shown in FIG. 1 to FIG. 6 , a specific embodiment of the present invention provides a multi-frequency smart antenna for an all-metal casing, including a metal casing 100 installed on the back of the system circuit board 800 and opened in the metal casing The slot 200 on the 100 and the feeding network 900 arranged on the front of the system circuit board 800; it is characterized in that:

A metal frame 102 extending from the back of the system circuit board 800 to the side is provided at the peripheral edges of the metal casing 100; the metal casing is provided with a first slit 201 and a second slit 202, and the first slit 201 It is a double-ended opening type slot, the second slot 202 is a single-ended opening type slot, and the first slot 201 and the second slot 202 divide the metal frame into three independent sections;

The feed network 900 includes: a feed branch 601, a feed branch 2 602, a matching circuit 1 701, a matching circuit 2 702, a feed port 400 and a gating circuit; the feed port and the feed branch are connected with a In the gating circuit, a matching circuit is connected between each feeding branch and the gating circuit, and the feeding branch spans the first slot 201 and the second slot 202 on the back of the system circuit board respectively.

As shown in FIG. 4 , the metal casing 100 includes a metal back cover 101 and a metal frame 102 on the peripheral side of the metal back cover. The metal back cover 101 and the metal frame 102 are connected to form the overall casing of the terminal device; It can be seen that a first slot 201 and a second slot 202 that communicate with each other are respectively provided on the metal back cover and the metal frame; A slit of 101, two slit belts are located at the beginning and end of the slit and are respectively connected with the above-mentioned slits to form a double-ended opening type slit, wherein: the width of the slit belt is the same as or different from the width of the slit, and the slit belt and the slit are the same or different. The width of the narrow slit is between 0.5 mm and 5 mm; the second slit 202 includes a slit strip opened on the metal frame 102 and another narrow slit opened on the metal back cover 101, and a slit strip is located at one end of the narrow slit The slits are respectively connected with the slits to form a single-ended open slit, wherein the width of the slit band is the same as or different from the width of the slit, and the widths of the slit band and the slit are between 0.5 mm and 5 mm. The slot 200 separates the metal casing into discontinuous areas, so that the slot radiation is used to avoid the adverse effect of the metal casing 100 on the antenna signal, thereby improving the antenna performance.

Further, the first gap 201 and the second gap 202 may be filled with non-metallic materials to ensure the strength of the metal casing.

Further, the size of the first slit 201 and the second slit 202 can be set according to specific conditions, which is not limited here. In this embodiment, the width of the two narrow slits 201 and 202 is preferably 3 mm.

FIG. 5 shows a schematic top view of the system circuit board 800 and the front feeding network 900 of the all-metal-shell mobile smart terminal antenna; with reference to FIG. 1 , the feeding network 900 on the front of the system circuit board 800 includes: a feeding port 400 , gating circuit 500, feed branch 1 601, feed branch 2 602, matching circuit 1 701 and matching circuit 2 702;

Wherein: the feed branch 1 601 specifically uses the L-shaped microstrip line with an open terminal as the feeding unit, so as to excite the first slot 201, and is connected to the gating circuit 500 provided on the system circuit board 800 through the matching circuit 1 701 The feed branch two 602 also adopts the L-shaped microstrip line with an open terminal as the feed unit, thereby exciting the second slot 202, and is connected with the gating circuit 500 arranged on the system circuit board 800 through the matching circuit two 702; The feeding port 400 is connected to the gating circuit 500 through a section of microstrip line. Therefore, the radio frequency signal is selected from the feeding point 400 to be fed into the feeding branch through the gating circuit 500; In the actual working process, the metal back cover 101 and the metal frame 102 connected to it together serve as the system ground.

In order to cover more 4G frequency bands, as a preferred implementation manner, this embodiment provides a schematic structural diagram of a U-shaped folded metal sheet 300 loaded on the first slot 201 , and FIG. 5 shows a U-shaped folded metal sheet 300 . The positional relationship between the chip 300 and the system circuit board. As shown in FIG. 5 , the horizontal plane of the U-shaped folded metal sheet 300 is isolated from the system circuit board, and non-metallic materials can be filled between the two, and the folded ends of the U-shaped folded metal sheet 300 pass downward. It is inserted into the system circuit board 800 and connected to its back metal shell (ie, the metal back cover 101 ), so that the U-shaped folded metal sheet and the first slot 201 form a single-ended opening. In this way, the U-shaped folded metal sheet 300 is combined with the first slot 201 to form a new resonance path, thereby realizing low-frequency resonance. The position and size of the U-shaped folded metal sheet 300 can be adjusted according to different user frequency bands, thereby realizing multi-band communication. demand.

Specifically, as shown in FIG. 7 , this example provides the form of a matching circuit for adjusting the impedance bandwidth of the antenna. The matching circuit 1 701 is shown in FIG. 7( a ), using C1 as a series capacitor and L1 as a parallel inductance; The second matching circuit 702 is shown in FIG. 7(b), in the form of a parallel capacitor C2 and a series inductor L2;

Specifically, this example also provides a schematic diagram of the gating circuit 500 connecting the feeding port 400 and the matching circuits 701 and 702, as shown in FIG. 8, when the switch selects the left side to be turned on, as shown in FIG. 8 ( As shown in a), the feeding branch 2 602 at the right end is open, and the RF signal feeds the first slot 201 of the U-shaped folded metal sheet 300 through the matching circuit 1 701 and the feeding branch 1 601, and the antenna works in state 1; when When the switch selects the right side to be turned on, as shown in Figure 8(b), the left feeder branch 1 601 is open, and the RF signal feeds the second slot 202 through the matching circuit 2 702 and the feeder branch 2 602, and the antenna works at State 2.

Specifically, as shown in FIG. 9. This embodiment provides a working block diagram of the gating circuit 500 located on the system circuit board 800 and used to connect the feeding port 400 and the matching circuits 701 and 702; the gating circuit 500 Including: gating switch, detection circuit and comparison control circuit; the gating switch pre-connects one of the feed branches, and takes this signal as a reference, the detection circuit monitors the two working signals in real time, and the detection index can be the detection amplitude or the It can be the phase, and then compare the signals on the two feed branches, and the comparison control circuit realizes the function of comparison and control. If the other signal is weaker than the reference signal, the switch will not respond and maintain the original state; The other signal is stronger than the reference signal, then the switch makes a switching response and uses the current state as the next reference signal. Through this technical means, the frequency reconstruction of the antenna is realized, that is, the frequency band is switched in real time according to the actual needs, and the different working frequency bands of the antenna are intelligently selected.

The multi-frequency terminal antenna provided by the present invention realizes the advantages of multi-frequency and wide frequency, and can cover the frequency band required for communication. Fig. 3, Fig. 5, Fig. 6 and Fig. 7 show the structural parameters of the antenna. In this implementation, l ₁ =43mm, w ₁ =w2 = 3mm, l ₂ =23mm, l ₃ =18mm, h=6mm, p ₁ =28mm, p ₂ =16.5mm, C ₁ =2.2pF, L ₁ =5.1nH, C ₂ =0.75pF, L ₂ =2.7nH; Return loss curve; as shown in Figure 11, this embodiment gives the efficiency curve of the antenna based on the above structural parameters; it can be seen from the above figure that the present invention is based on the double-ended open slot loading U-shaped folded metal sheet to form a three-dimensional The slot antenna structure, while realizing the miniaturization of the antenna, effectively covers the four 4G communication frequency bands of GSM850, GSM900, LTE2300 and LTE2500, the 5.8GHz WLAN frequency band and the two dominant 5G communication frequency bands in the future; further single-ended open type The slot antenna cooperates with the above-mentioned three-dimensional slot antenna structure to cover the three 4G communication frequency bands of DCS, PCS, and UMTS2100. Furthermore, in this embodiment, the frequency reconstruction function is incorporated by improving the feeding network, and by reasonably setting the gating circuit, the antenna can perform frequency band switching in real time according to actual needs during the working process, and intelligently select different working frequency bands of the antenna. In addition, the present invention provides an antenna device capable of realizing a fully metallized casing of the terminal device, except that the first slit 201 and the second slit 202 on the metal casing 100 are covered with metal. In other words, the present invention provides The side and back of the terminal equipment are almost completely covered with metal, which basically realizes the full metal coverage of the terminal equipment, and improves the user's demand for the metal texture and aesthetics of the fuselage.

Claims (8)

1. A multi-frequency terminal antenna for an all-metal casing, comprising a metal casing (100) installed on the back of a system circuit board (800), a slot (200) opened on the metal casing (100), and a slot (200) provided on the system circuit board (800) A feeding network (900) on the front side of a circuit board (800); characterized in that: A metal frame (102) extending from the back of the system circuit board (800) to the side is provided at the peripheral edges of the metal casing (100); the metal casing (100) is provided with a first slit (201) and a first slit (201) and a second slit (201). Two slits (202) and a U-shaped folded metal sheet (300); the U-shaped folded metal sheet (300) is partially suspended above the front surface of the system circuit board (800), and two ends of the U-shaped folded metal sheet (300) It penetrates into the system circuit board (800) and is connected to the metal shell on its back, so that the U-shaped folded metal sheet and the first slit (201) form a single-ended slit; the first slit (201) is double-ended an open slit, the second slit (202) is a single-ended open slit; the first slit (201) and the second slit (202) divide the metal frame (102) into three independent sections; The feeding network (900) includes: a feeding branch, a matching circuit and a feeding port (400); a matching circuit is connected between the feeding port (400) and the corresponding feeding branch, and the feeding branch is located across the system A first slot (201) and a second slot (202) on the back of the circuit board (800). 2. The multi-frequency terminal antenna for an all-metal casing according to claim 1, wherein the metal frame (102) comprises two long sides and two short sides arranged oppositely, and the two The second short sides of the strip are oppositely arranged and connected between the two long sides; the first slit (201) and the second slit (202) are arranged close to the short side of the metal frame (102). 3. A kind of multi-frequency terminal antenna for all-metal casing according to claim 2, characterized in that, the part of U-shaped folded metal sheet (300) that is suspended and the system circuit board (800) below it The space is also filled with non-metallic materials. 4. A kind of multi-frequency terminal antenna for all-metal casing according to claim 1, characterized in that, further comprising a gating circuit, and the gating circuit (500) is connected to the feeding branch and the feeding port ( 400) between. 5 . The multi-frequency terminal antenna for an all-metal casing according to claim 4 , wherein the gate circuit comprises a detection circuit, a comparison control circuit and a gate switch. 6 . 6. The multi-frequency terminal antenna for an all-metal casing according to any one of claims 1 to 5, wherein the width of the slot on the metal casing (100) is between 0.5 mm and 5 mm. 7. The multi-frequency terminal antenna for an all-metal casing according to any one of claims 1 to 5, wherein the opening width of the slot is the same as or different from the width of the slot, and the opening width of the slot is between between 0.5 mm and 5 mm. 8. The multi-frequency terminal antenna for an all-metal casing according to any one of claims 1 to 5, wherein the metal casing (100) serves as a system ground.