Multiband antenna

Abstract

A multiband antenna includes a coaxial cable and a printed circuit board. The printed circuit board comprises a first side surface and a second side surface. The first side surface comprises a feed-in point, a first radiator and a second radiator. The first radiator includes a plurality of first dipoles. The second radiator includes a plurality of second dipoles. The second side surface comprises a feed-in part, a third radiating body and a fourth radiating body. The third radiator comprises a plurality of third dipoles. The fourth radiator comprises a plurality of fourth dipoles. The plurality of first dipoles are respectively paired with the plurality of third dipoles to form a plurality of first multi-frequency dipole antennas, and the plurality of second dipoles are respectively paired with the plurality of fourth dipoles to form a plurality of second multi-frequency dipole antennas. The plurality of first multi-frequency dipole antennas and the plurality of second multi-frequency dipole antennas jointly excite a plurality of multi-band radio frequency signals. The utility model provides a multiband antenna technology which can provide a high-gain antenna structure and improve the radiation pattern of an antenna.

Description

Technical Field

[0001] This case involves an antenna structure. Specifically, it involves a novel multi-band dipole antenna structure. Background Art

[0002] As mobile communication technology matures, mobile network transmission speeds are increasing. However, this presents a challenge: the frequency bands that wireless communication devices must support are also increasing. Existing dipole antennas have drawbacks. At low frequencies, the wavelength required by the dipole makes the antenna structure complex and too large to be suitable for existing devices. Furthermore, existing dipole antennas offer poor signal transmission in specific directions. Therefore, how to utilize a single antenna to support a wide range of frequency bands and omnidirectional signals is a critical challenge in this field.

[0003] Therefore, the above technology still has many defects, and practitioners in this field are waiting to develop other suitable multi-band antennas. Utility Model Content

[0004] One aspect of the present invention relates to a multi-band antenna. The multi-band antenna includes a coaxial cable and a printed circuit board. The printed circuit board includes a first end, a second end, a first side, a second side, a first side, and a second side, wherein the first side is opposite to the second side. The first end and the second end are perpendicular to the first side and the second side, respectively. The first side includes a feeding point, a first radiator, and a second radiator. The feeding point is connected to the coaxial cable. The first radiator extends from the feeding point to the first side, and bends and extends toward the second end. The extended end of the first radiator bends toward the second side and extends to form a plurality of first dipoles. The second radiator extends from the feeding point to the second side opposite to the first side, and bends and extends toward the first end. The extended end of the second radiator bends toward the first side and extends to form a plurality of second dipoles. The second side includes a feeding portion, a third radiator, and a fourth radiator. The third radiator extends from the feeding portion to the first side, and bends and extends toward the second end. The extended end of the third radiator bends toward the second side and extends to form a plurality of third dipoles. The fourth radiator extends from the feed portion to the second side and bends and extends toward the first end. The extended end of the second radiator bends and extends toward the first side to form a plurality of fourth dipoles. The plurality of first dipoles are mirror-symmetrical with the plurality of third dipoles, and are paired to form a plurality of first multi-band dipole antennas. The plurality of second dipoles are mirror-symmetrical with the plurality of fourth dipoles, and are paired to form a plurality of second multi-band dipole antennas. The plurality of first multi-band dipole antennas and the plurality of second multi-band dipole antennas jointly excite multiple radio frequency signals in multiple frequency bands.

[0005] In some embodiments, the first radiator includes a first transmission line, a first impedance matching section, and a first impedance conversion section. The first transmission line is connected to a feed point. The first impedance matching section is connected to the first transmission line. The first impedance conversion section is connected to the first impedance matching section and the plurality of first dipoles.

[0006] In some embodiments, the second radiator includes a second transmission line, a second impedance matching section, and a second impedance conversion section. The second transmission line is connected to the feed point. The second impedance matching section is connected to the second transmission line. The second impedance conversion section is connected to the second impedance matching section and the plurality of second dipoles.

[0007] In some embodiments, the third radiator includes a third transmission line and a third impedance conversion portion, wherein the third transmission line is connected to the feeding portion, and the third impedance conversion portion is connected to the third transmission line and the plurality of third dipoles.

[0008] In some embodiments, the fourth radiator includes a fourth transmission line and a fourth impedance conversion portion, wherein the fourth transmission line is connected to the feeding portion, and the fourth impedance conversion portion is connected to the fourth transmission line and the plurality of fourth dipoles.

[0009] In some embodiments, the plurality of frequency bands include a first frequency band, a second frequency band, and a third frequency band, wherein the first frequency band is smaller than the second frequency band, and the second frequency band is smaller than the third frequency band.

[0010] In some embodiments, each of the plurality of first dipoles, the plurality of second dipoles, the plurality of third dipoles, and the plurality of fourth dipoles includes a first radiating arm, a second radiating arm, and a third radiating arm. The first radiating arm is configured to excite a plurality of radio frequency signals in the third frequency band. The second radiating arm is connected to the first radiating arm and is configured to excite a plurality of radio frequency signals in the first frequency band. The third radiating arm is connected to the first radiating arm and is configured to excite a plurality of radio frequency signals in the second frequency band.

[0011] In some embodiments, the first length of the first radiating arm is less than the second length of the third radiating arm, and the second length of the third radiating arm is less than the third length of the second radiating arm.

[0012] In some embodiments, a coaxial cable includes a center conductor layer and an outer conductor layer. The feed portion includes a via, a first connecting portion, and a second connecting portion. The first connecting portion connects to the via and the center conductor layer of the coaxial cable. The second connecting portion connects to the outer conductor layer of the coaxial cable.

[0013] In some embodiments, the second side surface is connected to the feeding point of the first side surface through a via.

[0014] In view of the aforementioned shortcomings and deficiencies of the prior art, the present invention provides a multi-band antenna technology that can provide a high-gain antenna structure and improve the antenna's radiation pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The content of this case can be better understood by referring to the embodiments in the following paragraphs and the following drawings:

[0016] Figure 1 Schematic diagram of the antenna structure of a multi-band antenna according to some embodiments of the present invention;

[0017] Figure 2 Schematic diagrams of top and bottom views of the antenna structure of a multi-band antenna according to some embodiments of the present invention;

[0018] Figure 3 is an enlarged schematic diagram of a portion of the antenna structure of a multi-band antenna according to some embodiments of the present invention;

[0019] Figure 4A is a graph showing antenna radiation efficiency of a multi-band antenna according to some embodiments of the present invention;

[0020] Figure 4B is a graph showing antenna radiation gain curves of a multi-band antenna according to some embodiments of the present invention;

[0021] Figure 5A FIG1 is a diagram showing the radiation pattern of a dipole antenna in the XY plane according to the prior art;

[0022] Figure 5B FIG1 is a diagram showing the antenna radiation pattern of a multi-band antenna in the XY plane according to some embodiments of the present invention;

[0023] Figure 6A FIG1 is a diagram showing the radiation pattern of a dipole antenna in the XY plane according to the prior art;

[0024] Figure 6B FIG1 is a diagram showing the antenna radiation pattern of a multi-band antenna in the XY plane according to some embodiments of the present invention;

[0025] Figure 7A FIG1 is a diagram showing the radiation pattern of a dipole antenna in the XY plane according to the prior art;

[0026] Figure 7B FIG2 is an antenna radiation pattern diagram of a multi-band antenna in the XY plane according to some embodiments of the present invention.

[0027] Reference numerals:

[0028] 100: Multi-band antenna

[0029] B: Printed Circuit Board

[0030] S1: First side

[0031] S2: Second side

[0032] FB 1, FB 2, FB 3, FB 4: Dipole

[0033] BB 1, BB 2, BB 3, BB 4: Dipole

[0034] FL 1, FL 2, FL 3, FL 4: Transmission lines

[0035] BL 1, BL 2, BL 3, BL 4: Transmission lines

[0036] C: Coaxial cable

[0037] M1, M2: Impedance matching section

[0038] FT 1, FT 2, BT 1, BT 2: Impedance conversion unit

[0039] P 1: Feeding point

[0040] FA 1, FA 2, FA 3: radiating arms

[0041] BA 1, BA 2, BA 3: radiating arms

[0042] F 1: Feeding section

[0043] Z: Enlarged view

[0044] H: Via hole

[0045] CP 1: First connection

[0046] CP 2: Second connection

[0047] 200: Antenna radiation efficiency curve

[0048] 300: Antenna radiation gain curve

[0049] 400, 500, 600, 700, 800, 900: Antenna pattern DETAILED DESCRIPTION

[0050] The following drawings and detailed descriptions clearly illustrate the spirit of the present invention. After understanding the embodiments of the present invention, anyone skilled in the art can make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0051] The terms used herein are for describing specific embodiments only and are not intended to be limiting of the present invention. Singular forms such as "a," "the," "this," "this," and "the" as used herein also include plural forms.

[0052] Regarding the terms "include", "include", "have",

[0053] "Contain" and the like are open-ended terms, meaning including but not limited to.

[0054] Unless otherwise noted, the terms used herein generally have their ordinary meanings in the art, in the context of this application, and in the specific context. Certain terms used to describe this application are discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art regarding the description of this application.

[0055] To make the antenna structure of the multi-band antenna 100 of the present invention easier to understand, please refer to Figure 1 and Figure 2 , Figure 1 FIG. 1 is a schematic diagram of the antenna structure of a multi-band antenna 100 according to some embodiments of the present invention. Figure 2 According to some embodiments of the present invention Figure 1 The multi-band antenna 100 includes a top view and a bottom view of the antenna structure. The multi-band antenna 100 includes a printed circuit board B and a coaxial cable C. The printed circuit board B includes a first side surface S1 and a second side surface S2. Figure 1 , the first side S1 includes Figure 1 The second side surface S2 includes Figure 1 The detailed solid and dotted lines will be matched with Figure 2 and subsequent paragraphs for explanation.

[0056] In some embodiments, the coaxial cable C comprises a center conductor layer, a plastic insulation layer, an outer conductor layer, and a protective layer (not shown). The center conductor layer is typically a conductive copper wire. The plastic insulation layer serves as an insulator or dielectric. The outer conductor layer is typically a mesh conductor (e.g., copper or an alloy). The protective layer is typically a material that insulates the cable from the outside world.

[0057] It should be noted that the dotted line structure is used to represent the approximate symmetry with the solid line structure of the multi-band antenna 100 of this embodiment. In fact, the position of the dotted line structure is offset, and part of the dotted line structure is Figure 1 Some are omitted. For detailed dotted line structure, please refer to Figure 2 FIG. 1 is a bottom view of the antenna structure of the multi-band antenna 100 .

[0058] See also Figure 2The upper figure shows the first side S1 of the printed circuit board B. The first side S1 is a top view of the front of the printed circuit board B. The upper figure shows the second side S2 of the printed circuit board B. The second side S2 is a bottom view of the back of the printed circuit board B. The first side S1 is opposite to the second side S2. The first side S1 and the second side S2 together include a first end (i.e., the right side of the figure), a second end (i.e., the left side of the figure), a first side edge (i.e., the top of the figure), and a second side edge (i.e., the bottom of the figure).

[0059] In some embodiments, see Figure 2 In the upper figure, the first side S1 of the printed circuit board B includes a feed point P1, a first radiator, and a second radiator. The first radiator includes transmission lines FL1 and FL3, an impedance matching section M1, an impedance transformation section FT1 (i.e., the dotted portion in the figure), and a plurality of first dipoles (e.g., dipoles FB1 and FB2). The second radiator includes transmission lines FL2 and FL4, an impedance matching section M1, an impedance transformation section FT2 (i.e., the dotted portion in the figure), and a plurality of second dipoles (e.g., dipoles FB3 and FB4).

[0060] The first radiator extends from feed point P1 to the first side of the printed circuit board B (i.e., the top in the figure), then bends and extends toward the second end (i.e., the left in the figure). The first radiator then extends to form an impedance matching portion M1, which continues to extend toward the second end. Furthermore, the first radiator extends to form the first segment (i.e., the top segment) of the impedance transformation portion FT1. The extended end of the first radiator bends and extends toward the second side (i.e., the bottom in the figure) to form a transmission line FL3. Transmission line FL3 branches out through the second segment (i.e., the left segment) and the third segment (i.e., the right segment) of the impedance transformation portion FT1 to form a plurality of first dipoles (e.g., dipole FB1 and dipole FB2). In other words, the second segment of the impedance transformation portion FT1 is connected to dipole FB1. The third segment of the impedance transformation portion FT1 is connected to dipole FB2.

[0061] The second radiator extends from feed point P1 to the second side of the printed circuit board B opposite the first side (i.e., the bottom side in the figure), then bends toward the first end (i.e., the right side in the figure) and extends. The second radiator then extends to form an impedance matching portion M2, which continues to extend toward the first end. Furthermore, the second radiator extends to form a first segment (i.e., the bottom segment) of an impedance transformation portion FT2. The extended end of the second radiator bends toward the first side (i.e., the top side in the figure) and extends to form a transmission line FL4. Transmission line FL4 branches into a plurality of second dipoles (e.g., dipole FB3 and dipole FB4). The second segment (i.e., the left segment) of the impedance transformation portion FT2 is connected to dipole FB3. The third segment (i.e., the right segment) of the impedance transformation portion FT2 is connected to dipole FB4.

[0062] See also Figure 2 In the bottom view below, the first side S2 of the printed circuit board B includes a feed portion F1, a third radiator, and a fourth radiator. The third radiator includes transmission lines BL1 and BL3, an impedance transformation portion BT1 (i.e., the dotted portion in the diagonal lines in the figure), and a plurality of third dipoles (e.g., dipoles BB1 and BB2). The fourth radiator includes transmission lines BL2 and BL4, an impedance transformation portion BT2 (i.e., the dotted portion in the diagonal lines in the figure), and a plurality of fourth dipoles (e.g., dipoles BB3 and BB4).

[0063] The third radiator extends from the feed portion F1 to the first side of the printed circuit board B (the lower side in the figure, as this is a bottom view), then bends and extends toward the second end (i.e., the left side in the figure). The third radiator then extends to form the first segment (i.e., the lower segment) of the impedance transformation portion BT1. The third radiator's extended end bends and extends toward the second side (i.e., the upper side in the figure, as this is a bottom view) to form a transmission line BL3. Transmission line BL3 branches into a plurality of third dipoles (e.g., dipole BB1 ​​and dipole BB2). The second segment (i.e., the left segment) of the impedance transformation portion BT1 is connected to dipole BB1. The third segment (i.e., the right segment) of the impedance transformation portion FT2 is connected to dipole BB2.

[0064] The fourth radiator extends from the feed portion F1 to the second side of the printed circuit board B (the upper side in the figure, as this is a bottom view), then bends and extends toward the first end (i.e., the right side in the figure). The third radiator then extends to form the first segment (i.e., the upper segment) of the impedance transformation portion BT2. The third radiator's extended end bends and extends toward the first side (i.e., the lower side in the figure, as this is a bottom view) to form a transmission line BL4. Transmission line BL4 branches into a plurality of fourth dipoles (e.g., dipoles BB3 and BB4). The second segment (i.e., the left segment) of the impedance transformation portion BT2 is connected to dipole BB3. The third segment (i.e., the right segment) of the impedance transformation portion FT2 is connected to dipole BB4.

[0065] Multiple first dipoles are paired with multiple third dipoles to form multiple first multi-band dipole antennas. For example, dipole FB 1 and dipole BB 1 are mirror-image symmetrical and paired to form a first multi-band dipole antenna. Dipole FB 2 and dipole BB 2 are mirror-image symmetrical and paired to form a first multi-band dipole antenna.

[0066] Next, the plurality of second dipoles are paired with the plurality of fourth dipoles to form a plurality of second multi-band dipole antennas. For example, dipole FB 3 and dipole BB 3 are mirror-imaged to form a second multi-band dipole antenna. Dipole FB 4 and dipole BB 4 are mirror-imaged to form a second multi-band dipole antenna.

[0067] Furthermore, multiple first multi-frequency dipole antennas and multiple second multi-frequency dipole antennas jointly excite multiple radio frequency signals in multiple frequency bands and determine the field pattern formed by the multiple radio frequency signals. The mirror structure designed in this case makes it easy to adjust the matching impedance of the antenna, reducing the difficulty of designing the antenna structure, and the field patterns of the first multi-frequency dipole antenna and the second multi-frequency dipole antenna complement each other so that the field pattern is close to a circle. In some embodiments, the multiple frequency bands include a first frequency band, a second frequency band, and a third frequency band. The first frequency band is smaller than the second frequency band. The second frequency band is smaller than the third frequency band. For example, the first frequency band can be implemented as 2 gigahertz (GHz). The second frequency band can be implemented as 5 gigahertz (GHz). The third frequency band can be implemented as 6 gigahertz (GHz). It should be noted that the frequency band can be designed according to actual needs and is not limited to the embodiments of this case.

[0068] Please note that, please refer to Figure 1 and Figure 2The distances between dipoles FB1 and FB2, between dipoles FB3 and FB4, between dipoles BB1 and BB2, and between dipoles BB3 and BB4 must all be at least the distance of one dipole. In other words, the extended length of transmission line FL1 and impedance transformer FT1 must be at least greater than the distance of one multi-band dipole antenna (equivalent to the length of dipole FB2 plus the length of dipole BB2).

[0069] In some embodiments, see Figure 2 The dipole FB1 on the left side of the upper figure includes a first radiating arm FA1, a second radiating arm FA2, and a third radiating arm FA3. The first radiating arm FA1 is connected to the impedance transformation portion FT1. The second radiating arm FA2 is connected to the first radiating arm FA1. The third radiating arm FA3 is connected to the second radiating arm FA2. The length of the first radiating arm FA1 is shorter than the length of the third radiating arm FA3. The length of the third radiating arm FA3 is shorter than the length of the second radiating arm FA2.

[0070] Please refer to Figure 2 The dipole BB1 ​​on the left side of the bottom view below includes a first radiating arm BA1, a second radiating arm BA2, and a third radiating arm BA3. The first radiating arm BA1 is connected to the impedance transformer BT1. The second radiating arm BA2 is connected to the first radiating arm BA1. The third radiating arm BA3 is connected to the second radiating arm BA2. The length of the first radiating arm BA1 is shorter than the length of the third radiating arm BA3. The length of the third radiating arm BA3 is shorter than the length of the second radiating arm BA2.

[0071] To make the frequency modulation mechanism of the multi-band antenna 100 easier to understand, please refer to Figures 1 to 3The electrical signal is transmitted via the coaxial cable C to the feeding point P1 on the first side S1 and the feeding portion F1 on the second side S2. The electrical signal is then converted by the impedance matching portion (e.g., impedance matching portion M1 and impedance matching portion M2) and the impedance transformation portion (e.g., impedance transformation portion FT1 and impedance transformation portion FT2 on the first side S1, and impedance transformation portion BT1 and impedance transformation portion BT2 on the second side S2) on the first side S1. Finally, the first radiating arm FA1 of dipole FB1 and the first radiating arm BA1 of dipole BB1 ​​jointly excite an RF signal in the aforementioned third frequency band (e.g., 6 GHz). Simultaneously, the second radiating arm FA2 of dipole FB1 and the second radiating arm BA2 of dipole BB1 ​​jointly excite an RF signal in the aforementioned first frequency band (e.g., 2 GHz). At the same time, the third radiating arm FA 3 of the dipole FB 1 and the third radiating arm BA 3 of the dipole BB 1 jointly excite the radio frequency signal in the second frequency band (eg, 5 GHz).

[0072] The structures of dipoles FB 2, FB 3, and FB 4 are similar to those of dipole FB 1 and are not described in detail here. The structures of dipoles BB 2, BB 3, and BB 4 are similar to those of dipole BB 1 and are not described in detail here.

[0073] Also, see Figure 2 In the upper figure, the portion from feed point P1 to transmission lines FL1 and FL2 is a one-to-two power divider. The branches of transmission lines FL3 and FL4 are also two-to-one power dividers. Therefore, the antenna structure of the multi-band antenna 100 includes three one-to-two power dividers.

[0074] Figure 3 According to some embodiments of the present invention Figure 1 and Figure 2 FIG. 2 is a schematic diagram of an enlarged view Z of a portion of the antenna structure of the multi-band antenna 100 . Figure 3 The enlarged image Z corresponds to Figure 2 The enlarged view Z of the second side surface S2 of the multi-band antenna 100 is shown. Figure 1 、 Figure 2 and Figure 3 Feeding portion F1 includes a via H, a first connection portion CP1, and a second connection portion CP2. The via H on the second side S2 connects to the feeding point P1 on the first side S1. The first connection portion CP1 connects to the via H and the center conductor layer of the coaxial cable C. The second connection portion CP2 connects to the outer conductor layer of the coaxial cable C.

[0075] Figure 4A FIG2 is a graph 200 illustrating the antenna radiation efficiency of the multi-band antenna 100 according to some embodiments of the present invention. Figure 4A The multi-band antenna 100 of the present invention has a radiation efficiency of approximately 60% to 70% in the first frequency band (i.e., 2.4-2.5 GHz). The multi-band antenna 100 of the present invention has a radiation efficiency of approximately 45% to 70% in the second frequency band (i.e., 5.15-5.85 GHz). The multi-band antenna 100 of the present invention has a radiation efficiency of approximately 50% to 75% in the third frequency band (i.e., 5.925-7.125 GHz). The multi-band antenna 100 of the present invention has a best radiation efficiency of 73.77% at a frequency of 5.75 GHz.

[0076] Figure 4B FIG3 is a graph 300 showing the antenna radiation gain curve of the multi-band antenna 100 according to some embodiments of the present invention. Figure 4B The multi-band antenna 100 of the present invention has a radiation gain of approximately 4 dB Bi in the first frequency band (i.e., 2.4-2.5 GHz). The multi-band antenna 100 of the present invention has a radiation gain of approximately 5 dB Bi to 7 dB Bi in the second frequency band (i.e., 5.15-5.85 GHz). The multi-band antenna 100 of the present invention has a radiation gain of approximately 6.5 dB Bi to 8.5 dB Bi in the third frequency band (i.e., 5.925-7.125 GHz). The optimal radiation gain of the multi-band antenna 100 of the present invention is 8.05 dB Bi at a frequency of 7.125 GHz.

[0077] Figure 5A The antenna pattern diagram 400 of the dipole antenna in the XY plane is shown according to the prior art. Figure 5A When transmitting signals within the 2.45GHz frequency band (i.e., the first frequency band), the radiation pattern of the conventional dipole antenna resembles a figure-8 or hourglass shape. In other words, the conventional dipole antenna has poor signal quality in the concave areas of the figure-8 or hourglass radiation pattern (i.e., specific directions). Figure 5B FIG5 is an antenna pattern diagram 500 of the multi-band antenna 100 in the XY plane according to some embodiments of the present invention. Figure 5B When the multi-band antenna 100 of the present invention transmits a signal at a frequency of 2.45 GHz (i.e., the first frequency band), the radiation pattern of the multi-band antenna 100 is approximately in the shape of a figure 8 or an hourglass. Figure 5A The concave portion of the radiation pattern of the multi-band antenna 100 is better than the concave portion of the radiation pattern of the conventional dipole antenna.

[0078] Figure 6AFIG600 is an antenna pattern diagram 600 of a dipole antenna in the XY plane according to the prior art. Figure 6A When the conventional dipole antenna transmits signals within the 5.15 GHz frequency band (i.e., the second frequency band), the radiation pattern of the conventional dipole antenna is approximately irregular. In other words, the conventional dipole antenna has poor signal quality in the concave areas of the irregular radiation pattern. Figure 6B FIG7 is an antenna pattern diagram 700 of the multi-band antenna 100 in the XY plane according to some embodiments of the present invention. Figure 6B When the multi-band antenna 100 of this embodiment transmits a signal at a frequency of 5.15 GHz (i.e., the second frequency band), the radiation pattern of the multi-band antenna 100 is approximately elliptical or circular. Figure 6A The radiation pattern of the multi-band antenna 100 is better than that of the conventional dipole antenna, thereby enhancing the signal strength in a specific direction.

[0079] Figure 7A The antenna pattern diagram 800 of the dipole antenna in the XY plane is shown according to the prior art. Figure 7A When transmitting signals at a frequency of 6.25 GHz (i.e., the third frequency band), the radiation pattern of conventional dipole antennas resembles a figure-eight or hourglass shape. In other words, conventional dipole antennas have poor signal quality in the concave areas of the figure-eight or hourglass radiation pattern (i.e., specific directions).

[0080] Figure 7B FIG. 9 is an antenna pattern diagram 900 of the multi-band antenna 100 in the XY plane according to some embodiments of the present invention. Figure 7B When the multi-band antenna 100 of this embodiment transmits a signal at a frequency of 6.25 GHz (i.e., the third frequency band), the radiation pattern of the multi-band antenna 100 is approximately elliptical or circular. Figure 7A The radiation pattern of the multi-band antenna 100 is better than that of the conventional dipole antenna, thereby enhancing the signal strength in a specific direction.

[0081] According to the aforementioned embodiments, the present invention provides a multi-band antenna structure that can radiate multiple frequency bands simultaneously and has good antenna radiation characteristics. The antenna radiation pattern is close to a circle, thereby enhancing the signal strength in a specific direction.

[0082] Although the present invention is disclosed above with detailed embodiments, other feasible implementations are not excluded. Therefore, the scope of protection of the present invention shall be determined by the scope of the appended patent applications, rather than being limited by the aforementioned embodiments.

[0083] It is obvious to those skilled in the art that various modifications and alterations can be made to the present invention without departing from the spirit and scope of the present invention. Based on the aforementioned embodiments, all modifications and alterations made to the present invention are also included in the scope of protection of the present invention.

Claims

1. A multi-band antenna, characterized in that: Include: coaxial cable; as well as Printed circuit board, including: a first end and a second end; a first side and a second side, wherein the first end and the second end are respectively perpendicular to the first side and the second side; a first side surface and a second side surface, wherein the first side surface is opposite to the second side surface; The first side comprises: a feed point connected to the coaxial cable; A first radiator extends from the feed point to the first side and bends and extends toward the second end, wherein an extended end of the first radiator bends and extends toward the second side to form a plurality of first dipoles; as well as a second radiator extending from the feeding point to the second side opposite to the first side, and bending and extending toward the first end, wherein an extended end section of the second radiator bends and extends toward the first side to form a plurality of second dipoles; The second side comprises: A feeding portion connected to the coaxial cable and connected to the first side surface through the feeding point; a third radiator extending from the feeding portion to the first side and bending and extending toward the second end, wherein an extended end portion of the third radiator bends and extends toward the second side to form a plurality of third dipoles; as well as a fourth radiator extending from the feeding portion to the second side and bending and extending toward the first end; an extended end portion of the second radiator bending and extending toward the first side to form a plurality of fourth dipoles; The plurality of first dipoles are mirror-symmetrical with the plurality of third dipoles to form a plurality of first multi-band dipole antennas when paired, and the plurality of second dipoles are mirror-symmetrical with the plurality of fourth dipoles to form a plurality of second multi-band dipole antennas when paired. The plurality of first multi-band dipole antennas and the plurality of second multi-band dipole antennas jointly excite a plurality of radio frequency signals in multiple frequency bands.

2. The multi-band antenna according to claim 1, wherein: The first radiator comprises: A first transmission line connected to the feed point; a first impedance matching section connected to the first transmission line; and The first impedance conversion part is connected to the first impedance matching part and the plurality of first dipoles.

3. The multi-band antenna according to claim 2, wherein: The second radiator comprises: a second transmission line connected to the feed point; a second impedance matching section connected to the second transmission line; and The second impedance conversion part is connected to the second impedance matching part and the plurality of second dipoles.

4. The multi-band antenna according to claim 3, wherein: The third radiator comprises: A third transmission line connected to the feeding portion; and The third impedance conversion unit is connected to the third transmission line and the plurality of third dipoles.

5. The multi-band antenna according to claim 4, wherein: The fourth radiator comprises: a fourth transmission line connected to the feeding portion; and The fourth impedance conversion unit is connected to the fourth transmission line and the plurality of fourth dipoles.

6. The multi-band antenna according to claim 1, wherein: The multiple frequency bands include a first frequency band, a second frequency band, and a third frequency band, wherein the first frequency band is smaller than the second frequency band, and the second frequency band is smaller than the third frequency band.

7. The multi-band antenna according to claim 6, wherein: Each of the plurality of first dipoles, the plurality of second dipoles, the plurality of third dipoles, and the plurality of fourth dipoles includes: A first radiating arm, configured to excite the plurality of radio frequency signals in the third frequency band; a second radiating arm connected to the first radiating arm and configured to excite the plurality of radio frequency signals in the first frequency band; as well as The third radiation arm is connected to the first radiation arm and is used to excite the plurality of radio frequency signals in the second frequency band.

8. The multi-band antenna according to claim 7, wherein: A first length of the first radiating arm is smaller than a second length of the third radiating arm, wherein the second length of the third radiating arm is smaller than a third length of the second radiating arm.

9. The multi-band antenna according to claim 1, wherein: The coaxial cable includes a central conductor layer and an outer conductor layer, wherein the feeding portion includes: vias; a first connecting portion connected to the via hole and the central conductor layer of the coaxial cable; and The second connecting portion is connected to the outer conductor layer of the coaxial cable.

10. The multi-band antenna according to claim 9, wherein: The second side surface is connected to the feeding point of the first side surface through the conducting hole.

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