Antenna structure

Abstract

Provided is an antenna structure. The antenna structure comprises a first frequency band antenna and a second frequency band antenna; the first frequency band antenna is operated in a first frequency band; the second frequency band antenna is operated in a second frequency band and comprises a feed-in part, a balun and at least one antenna unit; the balun is connected with the feed-in part; the antenna unit is connected with the balun; the first frequency band is different from the second frequency band. Therefore, according to the antenna structure, the isolation degree between the first frequency band antenna and the second frequency band antenna is increased through the balun.

Description

Technical Field

[0001] The present invention relates to an antenna structure, and in particular to a multi-band antenna structure. Background Art

[0002] When dual-band electronic devices operate in both bands simultaneously, the requirements for adjacent channel rejection (ACR) are extremely high. In addition, in high-power, outdoor or external antenna conditions, the interference between the dual bands is more serious. Therefore, electronic devices with external high-gain antennas have increasing requirements for isolation.

[0003] Existing electronic devices can reduce the interference received by adjacent antennas by increasing the distance between adjacent frequency band antennas to extend the electrical length / path (Electrical Length) of electromagnetic waves radiated in the air. However, this method of increasing isolation will increase the overall size of the antenna. In addition, isolators are installed between dual-band antennas to reduce the interference energy of adjacent antennas, but this requires adjustment of the parameters of the antenna itself.

[0004] In view of this, developing an antenna structure that can increase antenna isolation has become a worthy research and development goal for relevant industries. Summary of the invention

[0005] Therefore, an object of the present invention is to provide an antenna structure, which connects a balun between a feeding portion and an antenna unit to isolate antennas of different frequency bands.

[0006] According to an embodiment of the structural aspect of the present invention, an antenna structure is provided, comprising a first frequency band antenna and a second frequency band antenna. The first frequency band antenna operates in a first frequency band. The second frequency band antenna operates in a second frequency band and comprises a feed portion, a balun and at least one antenna unit. The balun is connected to the feed portion. The antenna unit is connected to the balun. The first frequency band is different from the second frequency band.

[0007] According to another embodiment of the structural aspect of the present invention, an antenna structure is provided, comprising a first antenna array and a second antenna array. The first antenna array operates in a first frequency band. The second antenna array operates in a second frequency band and comprises a feed portion, a power divider, a plurality of antenna units and a balun. The power divider is connected to the feed portion. These antenna units are connected to the power divider. The balun is connected between the power divider and one of these antenna units. The first frequency band is different from the second frequency band.

[0008] The antenna structure of the present invention has the following advantages: first, the isolation between the first frequency band antenna and the second frequency band antenna can be increased by a balanced-unbalanced converter; second, a choke element is added at the front end to prevent the radio frequency signal from flowing into the ground; third, a balanced-unbalanced converter is arranged between at least one antenna unit and a power divider to enhance the current distribution characteristics and maintain a good antenna impedance, thereby achieving a decoupling effect; fourth, without affecting the overall performance of the second antenna array, the important parameters of the antenna are maintained, and the isolation between different frequency bands in the antenna structure is improved; fifth, a through-hole array connected to the first surface and the second surface is arranged at the bottom of the substrate as an equivalent metal wall to prevent electromagnetic wave leakage, so that the antenna structure can still effectively exert the best performance under the premise of improving the antenna isolation. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A schematic diagram showing an antenna structure according to a first embodiment of the present invention is shown;

[0010] Figure 2 A schematic diagram showing an antenna structure according to a second embodiment of the present invention is shown;

[0011] Figure 3 A schematic diagram illustrating the antenna structure of the first embodiment of the third embodiment of the present invention;

[0012] Figure 4 Draw according to Figure 3 A schematic diagram comparing the isolation of the antenna structure of the first embodiment of the third implementation mode;

[0013] Figure 5 Draw according to Figure 3 Another comparative schematic diagram of the isolation of the antenna structure of the first embodiment of the third implementation mode;

[0014] Figure 6 Draw according to Figure 3 A schematic diagram of comparison of the voltage standing wave ratio of the second antenna array of the antenna structure of the first embodiment of the third implementation mode;

[0015] Figure 7 Draw according to Figure 3 A schematic diagram comparing the efficiencies of the second antenna array of the antenna structure of the first embodiment of the third implementation mode;

[0016] Figure 8 Draw according to Figure 3 A schematic diagram of a first antenna subarray of a second antenna array of an antenna structure of a second example of a third implementation manner;

[0017] Fig. 9 Draw according to Figure 3 A schematic diagram of a first antenna subarray of a second antenna array of an antenna structure of a third example of a third implementation manner;

[0018] Fig.10 Draw according to Figure 3 A schematic diagram of a second antenna array of a fourth embodiment of the third implementation mode;

[0019] Fig.11 Draw according to Fig.10 A side view of a second antenna array of a fourth example of the third embodiment; and

[0020] Fig.12 Draw according to Fig.10 A schematic diagram of an antenna unit of a second antenna array of a fourth example of the third implementation manner.

[0021] Main component symbols:

[0022] 100, 100a, 200 antenna structure

[0023] 110 First Band Antenna

[0024] 120, 120a Second frequency band antenna

[0025] 121, 221 Feeding Department

[0026] 122, 222 Balun

[0027] 123, 223 antenna units

[0028] 124 Choke element

[0029] 210 First antenna array

[0030] 220, 220a second antenna array

[0031] 2231 base plate

[0032] 2232 First Radiant

[0033] 2233 Second radiator

[0034] 2234 Through-hole array

[0035] 2235 Spacing

[0036] 225 Panels

[0037] 2251 Opening

[0038] 230 Third Antenna Array

[0039] A1, A3, A4 first antenna subarray

[0040] A2 Second antenna subarray

[0041] C1 Connection

[0042] G1, G2 grounding part

[0043] H1 Through hole

[0044] L Length

[0045] M1 First matching section

[0046] M2 Second matching section

[0047] P1 First antenna port

[0048] P2 Second antenna port

[0049] P3 Third antenna port

[0050] P4 Fourth antenna port

[0051] R1 First radiating part

[0052] R2 Second radiating part

[0053] S1 Side 1

[0054] S2 Side 2

[0055] T1 Power Splitter DETAILED DESCRIPTION

[0056] The following will describe multiple embodiments of the present invention with reference to the accompanying drawings. For the purpose of clarity, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are not necessary. In addition, in order to simplify the drawings, some well-known and commonly used structures and elements will be depicted in a simple schematic manner in the drawings; and repeated elements may be represented by the same number.

[0057] In addition, in this article, when a certain element (or unit or module, etc.) is "connected" to another element, it may refer to that the element is directly connected to another element, or it may refer to that a certain element is indirectly connected to another element, that is, there are other elements between the element and the other element. When it is explicitly stated that a certain element is "directly connected" to another element, it means that there are no other elements between the element and the other element. The terms first, second, third, etc. are only used to describe different elements, and there is no restriction on the elements themselves. Therefore, the first element can also be renamed as the second element. Moreover, the combination of elements / units / circuits in this article is not a generally known, conventional or well-known combination in this field. Whether the elements / units / circuits themselves are well-known cannot be used to determine whether their combination relationship is easy to be easily completed by ordinary technicians in the technical field.

[0058] See also Figure 1 , Figure 1 A schematic diagram of an antenna structure 100 according to a first embodiment of the present invention is shown. The antenna structure 100 includes a first frequency band antenna 110 and a second frequency band antenna 120. The first frequency band antenna 110 operates in a first frequency band. The second frequency band antenna 120 operates in a second frequency band and includes a feeding portion 121, a balun 122 and at least one antenna unit 123. The feeding portion 121 is connected between the ground portion G1 and the antenna unit 123, and the feeding portion 121 can be a feeding signal line. The balun 122 is connected between the feeding portion 121 and the ground portion G2. The antenna unit 123 is connected to the balun 122. The first frequency band is different from the second frequency band. Thus, the antenna structure 100 of the present invention can increase the isolation between the first frequency band antenna 110 and the second frequency band antenna 120 through the balun 122.

[0059] Specifically, a length of the balun 122 is L, and a wavelength of the second frequency band antenna 120 operating in the second frequency band is λ, which satisfies the following formula (1):

[0060]

[0061] Specifically, the shape of the balun 122 can be adjusted according to the space limitation of the second frequency band antenna 120. However, the overall length L of the balun 122 must meet the above formula (1). The length L can be as follows: Figure 1 The center line segment of the balun 122 is marked. In the first embodiment, the antenna unit 123 can be a dipole antenna, but the invention is not limited thereto.

[0062] For example, when the antenna structure 100 has both WiFi 6E and WiFi 7 dual bands (i.e., the first band and the second band), when the coupling amount between the frequencies of 5725MHz and 5925MHz is relatively strong, the wavelength λ of 3 / 4 times the middle value of the aforementioned frequency range (i.e., 5800MHz) can be used in formula (1) to calculate the length L of the balun 122. In addition, when the width of the balun 122 is smaller, it can form a high impedance, and it is not easy to transmit the RF signal to the ground plane.

[0063] See also Figure 1 and Figure 2 , Figure 2A schematic diagram of an antenna structure 100a according to a second embodiment of the present invention is shown. The antenna structure 100a includes a first frequency band antenna 110 and a second frequency band antenna 120a. In the second embodiment, the structure of the first frequency band antenna 110 may be the same as that of the first frequency band antenna 110 of the first embodiment, or may be other antennas with different frequency band structures from the second frequency band antenna 120a, but the present invention is not limited thereto. The antenna structure 100a may further include a choke element 124. The choke element 124 is connected between the feed portion 121 and the balanced-to-unbalanced transformer 122 of the second frequency band antenna 120a. Thus, the antenna structure 100a of the present invention adds a choke element 124 to the front end of the second frequency band antenna 120a to prevent the radio frequency signal from flowing into the ground.

[0064] See also Figure 3 , Figure 3 A schematic diagram of an antenna structure 200 of a first embodiment of a third embodiment of the present invention is shown. The antenna structure 200 includes a first antenna array 210, a second antenna array 220, and a third antenna array 230. The first antenna array 210 operates in a first frequency band. The second antenna array 220 operates in a second frequency band and includes a feed portion 221, a power divider T1, a plurality of antenna units 223, and a balun 222. The power divider T1 is connected to the feed portion 221. These antenna units 223 are connected to the power divider T1. The balun 222 is connected between the power divider T1 and one of these antenna units 223. The third antenna array 230 operates in a third frequency band. The first frequency band, the second frequency band, and the third frequency band are different.

[0065] In detail, the antenna structure 200 includes antenna arrays corresponding to three frequency bands, and the first antenna array 210 is a patch antenna array operating at 5 GHz. The second antenna array 220 is a dipole antenna array operating at 6 GHz. The third antenna array 230 is a patch antenna array operating at 2 GHz. The second antenna array 220 includes a first antenna subarray A1 and a second antenna subarray A2. The first antenna subarray A1 includes a first antenna port P1, a feeding portion 221, a power divider T1, a balun 222, and a plurality of antenna units 223. The second antenna subarray A2 includes a second antenna port P2, a feeding portion 221, a power divider T1, a balun 222, and a plurality of antenna units 223. The first antenna port P1 and the second antenna port P2 distribute the signal evenly to all antenna units 223 through the power divider T1 via the feeding portion 221. The first antenna array 210 may include a third antenna port P3 and a fourth antenna port P4. Figure 3In the embodiment, the power divider T1 is a 1 to 3 T-Junction Power Divider / Combiner. The number of branches of the power divider T1 can be adjusted according to the number of antenna units 223, but the present invention is not limited thereto.

[0066] exist Figure 3 In the embodiment of the present invention, the balun 222 is disposed in the first antenna subarray A1 to increase the isolation between the antenna arrays of the three frequency bands. In other embodiments of the present invention, the balun 222 may also be disposed between at least one antenna unit 223 in the first antenna subarray A1 or the second antenna subarray A2 in the second antenna array 220 and the power divider T1 to improve the isolation between the first antenna array 210 and the second antenna array 220, but the present invention is not limited thereto. Thus, the antenna structure 200 of the present invention is provided with the balun 222 between at least one antenna unit 223 and the power divider T1 to enhance the current distribution characteristics and maintain good antenna impedance, thereby achieving a decoupling effect.

[0067] See also Figure 3 and Figure 4 ,in Figure 4 Draw according to Figure 3 A third embodiment is a schematic diagram showing the comparison of the isolation of the antenna structure 200 of the first embodiment. In the third embodiment, the third antenna port P3 of the first antenna array 210 has the same polarization as the second antenna array 220. Specifically, Figure 4 It can be seen that it shows a comparison diagram of the isolation between the third antenna port P3 of the first antenna array 210 and the first antenna port P1 of the second antenna array 220 in the prior art without a balun and with a balun 222. When no balun 222 is provided between all antenna units 223 and the power divider T1, the isolation between the third antenna port P3 of the first antenna array 210 and the first antenna port P1 of the second antenna array 220 can reach up to -37 dB, and when a balun 222 is provided between one antenna unit 223 and the power divider T1, the isolation between the third antenna port P3 of the first antenna array 210 and the first antenna port P1 of the second antenna array 220 can reach up to -42.1 dB.

[0068] See also Figure 3 and Figure 5 ,in Figure 5 Draw according to Figure 3 Another comparative schematic diagram of the isolation of the antenna structure 200 of the first embodiment of the third implementation mode. In the third embodiment, the fourth antenna port P4 of the first antenna array 210 is orthogonally polarized with the second antenna array 220. Figure 5 It can be seen that it shows a comparison diagram of the isolation between the first antenna port P1 of the second antenna array 220 and the fourth antenna port P4 of the first antenna array 210 in the prior art without a balun and with a balun 222. When no balun 222 is provided between all antenna units 223 and the power divider T1, the isolation between the first antenna port P1 of the second antenna array 220 and the fourth antenna port P4 of the first antenna array 210 can reach up to -39.1 dB, and when a balun 222 is provided between one antenna unit 223 and the power divider T1, the isolation between the first antenna port P1 of the second antenna array 220 and the fourth antenna port P4 of the first antenna array 210 can reach up to -41.8 dB.

[0069] See also Figure 3 , Figure 6 as well as Figure 7 ,in Figure 6 Draw according to Figure 3 A schematic diagram comparing the voltage standing wave ratio of the second antenna array 220 of the antenna structure 200 of the first embodiment of the third implementation mode, Figure 7 Draw according to Figure 3 A schematic diagram comparing the efficiencies of the second antenna array 220 of the antenna structure 200 of the first embodiment of the third implementation mode. Figure 6 and Figure 7 It can be seen that the voltage standing wave ratio and efficiency of the second antenna array 220 without the balun 222 and with the balun 222 in the second frequency band are very different. Thus, the antenna structure 200 of the present invention maintains important antenna parameters without affecting the overall performance of the second antenna array 220, thereby improving the isolation between different frequency bands in the antenna structure 200.

[0070] See also Figure 3 , Figure 8 as well as Fig. 9 ,in Figure 8 Draw according to Figure 3 A schematic diagram of a first antenna subarray A3 of a second antenna array 220 of an antenna structure 200 of a second embodiment of a third implementation mode, Fig. 9 Draw according to Figure 3 A schematic diagram of a first antenna subarray A4 of a second antenna array 220 of an antenna structure 200 of a third embodiment of a third implementation mode. Figure 8 and Fig. 9 It can be seen that the difference between the second and third embodiments of the third implementation mode and the first embodiment lies in the location of the balun 222, and other structures and features are the same or similar to those of the first embodiment, which will not be described in detail. Figure 8In the embodiment, the balun 222 is disposed between the second antenna unit 223 from top to bottom and the power divider T1. Fig. 9 In the embodiment, the balun 222 is disposed between the third antenna unit 223 from top to bottom and the power divider T1. In other embodiments of the present invention, the balun 222 may also be disposed between any antenna unit 223 of the second antenna subarray A2 and the power divider T1, but the present invention is not limited thereto.

[0071] See also Figure 3 , Figures 10 to 12 ,in Fig.10 Draw according to Figure 3 A schematic diagram of a second antenna array 220a of a fourth embodiment of the third implementation mode, Fig.11 Draw according to Fig.10 A side view of the second antenna array 220a of the fourth example of the third implementation mode, Fig.12 Draw according to Fig.10 A schematic diagram of the antenna unit 223 of the second antenna array 220a of the fourth embodiment of the third implementation mode. Figures 10 to 12 It can be seen that the difference between the fourth embodiment of the third implementation mode and the first embodiment lies in the structure of the second antenna array 220 a , and other structures and features are the same or similar to those of the first embodiment, which will not be further described herein.

[0072] Specifically, each antenna unit 223 may include a substrate 2231, a first radiating element 2232, and a second radiating element 2233. The first radiating element 2232 is disposed on a first surface S1 of the substrate 2231, and includes a first matching portion M1, a second matching portion M2, and a first radiating portion R1. The first matching portion M1 is connected to the power divider T1 and the balun 222. The second matching portion M2 is connected to the first matching portion M1. The first radiating portion R1 is connected to the second matching portion M2. The second radiating element 2233 is disposed on a second surface S2 of the substrate 2231, and includes a connecting portion C1 and a second radiating portion R2. The second radiating portion R2 is connected to the connecting portion C1. An end of the first radiating portion R1 away from the second matching portion M2 and an end of the second radiating portion R2 away from the connecting portion C1 do not overlap.

[0073] In other words, the first radiating portion R1 located on the first surface S1 of the substrate 2231 and the second radiating portion R2 located on the second surface S2 of the substrate 2231 form a dipole antenna, and the first matching portion M1 and the second matching portion M2 are used for impedance matching.

[0074] In addition, the second antenna array 220a may further include a plate 225. The plate 225 has an opening 2251 and a grounded metal layer (not shown), wherein the feeding portion 221 and the power divider T1 are disposed on one side of the plate 225, and the grounded metal layer is disposed on the other side of the plate 225. The antenna unit 223 may further include a through hole array 2234. The through hole array 2234 is disposed at one end of the substrate 2231, and the through hole array 2234 passes through the opening 2251, so that the antenna unit 223 is fixed to the plate 225. The through hole array 2234 includes a plurality of through holes H1, and a spacing 2235 between two adjacent through holes H1 is represented by G. The wavelength of the second antenna array 220a operating in the second frequency band is λ, which meets the following formula (2):

[0075]

[0076] Furthermore, in order to achieve automated production, the antenna unit 223 is often connected to the board 225 using a dual in-line package (DIP) plug-in method. However, the DIP plug-in method may cause leakage of electromagnetic waves in the second frequency band and affect the impedance matching. Therefore, a through-hole array 2234 connected to the first surface S1 and the second surface S2 is provided at the bottom of the substrate 2231 as an equivalent metal wall to prevent electromagnetic wave leakage, thereby enabling the antenna structure 200 to effectively perform at its best performance while improving the antenna isolation.

[0077] It can be seen from the above embodiments that the antenna structure of the present invention has the following advantages. First, the isolation between the first frequency band antenna and the second frequency band antenna can be increased by a balanced-unbalanced converter; second, a choke element is added at the front end to prevent the radio frequency signal from flowing into the ground; third, a balanced-unbalanced converter is arranged between at least one antenna unit and the power divider to enhance the current distribution characteristics and maintain a good antenna impedance, thereby achieving a decoupling effect; fourth, without affecting the overall performance of the second antenna array, the important parameters of the antenna are maintained, and the isolation between different frequency bands in the antenna structure is improved; fifth, an array of through holes connected to the first surface and the second surface is arranged at the bottom of the substrate as an equivalent metal wall to prevent electromagnetic wave leakage, so that the antenna structure can still effectively exert its best performance under the premise of improving the antenna isolation.

[0078] Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Any person skilled in the art should be able to make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the attached claims.

Claims

1. An antenna structure, comprising: a first frequency band antenna, the first frequency band antenna operating in a first frequency band; as well as A second frequency band antenna, the second frequency band antenna operates in a second frequency band and comprises: a feeding part; a balun connected to the feeding portion; and At least one antenna unit, the at least one antenna unit connected to the balun; The first frequency band is different from the second frequency band.

2. The antenna structure according to claim 1, further comprising: A choke element is connected between the feeding portion and the balun. 3 . The antenna structure as claimed in claim 1 , wherein one end of the balun is connected to the feeding portion, and the other end of the balun is connected to a ground portion.

4. The antenna structure as claimed in claim 1, wherein a length of the balun is L, and a wavelength of the second frequency band antenna operating in the second frequency band is λ, which conforms to the following formula: in, N is a positive integer. The antenna structure as claimed in claim 1 , wherein the at least one antenna unit is a dipole antenna.

6. The antenna structure as claimed in claim 1, wherein the at least one antenna unit comprises: a substrate; A first radiation element, which is disposed on a first surface of the substrate and includes: a first matching portion, the first matching portion connecting the feeding portion and the balun; a second matching portion connected to the first matching portion; and a first radiating portion connected to the second matching portion; and A second radiation element, the second radiation element is disposed on a second surface of the substrate and comprises: a connecting portion; and a second radiating portion connected to the connecting portion; Wherein, an end of the first radiating portion away from the second matching portion and an end of the second radiating portion away from the connecting portion do not overlap.

7. The antenna structure according to claim 1, wherein: The second frequency band antenna also includes: a plate having an opening, wherein the feeding portion is disposed on the plate; The at least one antenna unit comprises: a substrate; and A through hole array is arranged at one end of the substrate and passes through the opening so that the at least one antenna unit is fixed to the plate.

8. The antenna structure as claimed in claim 7, wherein the through hole array comprises a plurality of through holes, a spacing between two adjacent through holes is G, and a wavelength of the second frequency band antenna operating in the second frequency band is λ, which satisfies the following formula:

9. An antenna structure, comprising: a first antenna array, the first antenna array operating in a first frequency band; as well as a second antenna array, the second antenna array operating in a second frequency band and comprising: a feeding part; a power distributor connected to the feeding part; A plurality of antenna units, the plurality of antenna units being connected to the power divider; and a balun connected between the power divider and one of the antenna units; The first frequency band is different from the second frequency band.

10. The antenna structure according to claim 9, further comprising: A choke element is connected between the power divider and the balun. 11 . The antenna structure as claimed in claim 9 , wherein one end of the balun is connected to the feeding portion, and the other end of the balun is connected to a ground portion.

12. The antenna structure as claimed in claim 9, wherein a length of the balun is L, and a wavelength of the second antenna array operating in the second frequency band is λ, which conforms to the following formula: in, N is a positive integer.

13. The antenna structure as claimed in claim 9, wherein each of the antenna units is a dipole antenna.

14. The antenna structure as claimed in claim 9, wherein each of the antenna units comprises: a substrate; A first radiation element, which is disposed on a first surface of the substrate and includes: a first matching section, the first matching section connecting the power divider and the balun; a second matching portion connected to the first matching portion; and a first radiating portion connected to the second matching portion; and A second radiation element, the second radiation element is disposed on a second surface of the substrate and comprises: a connecting portion; and a second radiating portion connected to the connecting portion; Wherein, an end of the first radiating portion away from the second matching portion and an end of the second radiating portion away from the connecting portion do not overlap.

15. The antenna structure according to claim 9, wherein: The second antenna array further includes: A plate having an opening, wherein the feeding portion and the power divider are disposed on the plate; Each of the antenna units comprises: a substrate; and A through hole array is arranged at one end of the substrate and passes through the opening so that each antenna unit is fixed to the plate.

16. The antenna structure as claimed in claim 15, wherein the through hole array comprises a plurality of through holes, a spacing between two adjacent through holes is G, and a wavelength of the second antenna array operating in the second frequency band is λ, which satisfies the following formula:

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