Antenna structure

Abstract

The present invention discloses an antenna structure, which includes a substrate, a plurality of reflector plates, a ground plane, a radiator, and a plurality of vias. The substrate has opposite first and second sides and includes a liquid crystal polymer material. These reflector plates are located on the first side of the substrate and arranged in an array. The ground plane is located on the second side of the substrate and overlaps with these reflector plates in the normal direction of the substrate. The radiator is located on the second side of the substrate and does not overlap with these reflector plates in the normal direction of the substrate. The radiator has a slotted hole defined by a first radiation branch and a second radiation branch, and this slotted hole is used to excite at least two operating modes in different frequency bands. The vias respectively pass through the substrate and are coupled to the reflector plates on the first side and coupled to the first ground plane on the second side. The present invention has the characteristics of multiple frequency bands, can avoid the surface wave effect caused by the potential difference of different grounds, and improve the antenna gain and directivity.

Description

Technical Field

[0001] The present invention relates to an antenna structure, and particularly to an antenna structure with a reflector array. Background Art

[0002] With the booming development of communication technologies, commercial mobile communication systems can already achieve high-speed data transmission, which is conducive to network service providers providing various services, such as multimedia audio and video streaming, real-time traffic reports, vehicle navigation, and real-time network communication, etc., network services that require a large amount of data transmission. In terms of hardware, the design of the antenna affects the transmission and reception efficiency of wireless signals. Therefore, how to design an antenna structure that has a wide frequency band range and at the same time has good radiation efficiency and antenna gain has become one of the goals pursued by related industries. Summary of the Invention

[0003] The present invention is an antenna structure, including a substrate, a plurality of reflectors, a first ground plane, a first radiator, and a plurality of vias. The substrate has opposite first and second sides and includes a liquid crystal polymer material. These reflectors are located on the first side of the substrate and are arranged in an array. The first ground plane is located on the second side of the substrate and overlaps with these reflectors in the normal direction of the substrate. The first radiator is located on the second side of the substrate and does not overlap with these reflectors in the normal direction of the substrate. The first radiator has a slotted hole defined by a first radiation branch and a second radiation branch, which defines at least two operating modes for exciting different frequency bands. The length of the first radiation branch is 0.23λ1 to 0.25λ1, and the length of the second radiation branch is 0.23λ2 to 0.25λ2, where λ1 and λ2 are the wavelengths corresponding to the first resonance frequency and the second resonance frequency of these operating modes respectively. These vias pass through the substrate respectively and couple these reflectors and the first ground plane on the first side and the second side of the substrate respectively.

[0004] According to one or more embodiments of the present invention, the first ground plane defines a notch, and the first radiator has a signal feeding end located in the notch.

[0005] According to one or more embodiments of the present invention, the substrate has a planar portion and a protrusion portion. The planar portion is substantially perpendicular to the protrusion portion, and these reflectors and the first radiator are located on the planar portion and the protrusion portion respectively.

[0006] According to one or more embodiments of the present invention, the slotted hole is an L-shaped slotted hole.

[0007] According to one or more embodiments of the present invention, the first radiator further includes a signal feeding end, a signal feeding branch, and a radiation branch. The signal feeding end is used to couple to an external terminal. The signal feeding branch couples to the signal feeding end. The radiation branch couples to the signal feeding branch and defines the slotted hole.

[0008] According to one or more embodiments of the present invention, the radiation branch is square or rectangular.

[0009] According to one or more embodiments of the present invention, the antenna structure further includes a second ground plane and a second radiator. The second ground plane is located on the first side of the substrate and is electrically connected to the first ground plane. The second radiator is located on the first side of the substrate and is coupled to the second ground plane. The second radiator and the first radiator form a dipole antenna.

[0010] According to one or more embodiments of the present invention, the signal feeding branch of the first radiator and the grounding branch of the second radiator overlap in the normal direction of the substrate.

[0011] According to one or more embodiments of the present invention, the first radiator includes a signal feeding end, a signal feeding branch, a grounding branch, and a radiation branch. The signal feeding end is used to couple to an external terminal. The signal feeding branch is coupled to the signal feeding end. The grounding branch is coupled to the first ground plane. The radiation branch is coupled to the signal feeding branch and the grounding branch, and defines a slotted hole.

[0012] According to one or more embodiments of the present invention, each of these reflectors is a rectangular frame or is rectangular, cross-shaped, or circular.

[0013] The beneficial effects of the present invention are at least as follows: The present invention can excite at least two different operating modes of frequency bands, so it has the characteristics of multiple frequency bands and can avoid the surface wave effect caused by the potential difference of different grounds. In addition, the present invention can reflect the electromagnetic waves emitted by the radiator back to the radiator, and at the same time has an effect similar to that of a notch filter, thereby making the overall radiation field pattern face upward above the reflector array, further improving the antenna gain and directivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more fully understand the embodiments and their advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0015] Figure 1A and Figure 1B are respectively the first-side plan view and the second-side plan view of the antenna structure according to an embodiment of the present invention;

[0016] Figure 1C is Figure 1B the enlarged plan view of the radiator shown;

[0017] Figure 2A and Figure 2B are respectively the return loss simulation results of the antenna structures according to an embodiment and a comparative example of the present invention;

[0018] Figure 3A is the second-side plan view of the antenna structure according to another embodiment of the present invention;

[0019] Figure 3B isFigure 3A An enlarged plan view of the radiator shown;

[0020] Figure 4A and Figure 4B Are respectively the first side plan view and the second side plan view of the antenna structure according to another embodiment of the present invention;

[0021] Figure 4C and Figure 4D Are respectively Figure 4A and Figure 4B An enlarged plan view of the radiator shown;

[0022] Figure 5A Is the second side plan view of the antenna structure according to another embodiment of the present invention;

[0023] Figure 5B Is Figure 5A An enlarged plan view of the radiator shown;

[0024] Figure 6 Is the first side plan view of the antenna structure according to another embodiment of the present invention;

[0025] Figure 7 Is the first side plan view of the antenna structure according to another embodiment of the present invention;

[0026] Figure 8 Is the first side plan view of the antenna structure according to another embodiment of the present invention;

[0027] Figure 9A Is the first side plan view of the antenna structure according to another embodiment of the present invention;

[0028] Figure 9B and Figure 9C Are respectively Figure 9A The three-dimensional view and the side view after the antenna structure of is bent. Detailed implementation manners

[0029] The following describes embodiments of the present invention. However, it can be understood that the embodiments provide many applicable concepts, which can be implemented in various specific contexts. The discussed and disclosed embodiments are for illustration only and are not intended to limit the scope of the present invention.

[0030] The terms used herein are only for describing specific embodiments and are not intended to limit the scope of the patent application. Unless otherwise restricted, the singular forms of "a" or "the" can also be used to represent the plural forms.

[0031] The following description and the claims may use the term "coupled" and its derivatives. In a specific embodiment, "coupled" may mean that two or more elements are in direct physical or electrical contact with each other, or do not contact each other directly.

[0032] In the present invention, each radiator is in the form of a monopole antenna, which can operate in a mode of quarter-wavelength resonance. In addition, the radiator has slotted holes, enabling the current to bifurcate into different paths, thereby exciting operation modes of at least two different frequency bands, and thus having the characteristic of multi-band. The reflector array and the ground plane are commonly grounded to avoid surface wave effects caused by potential differences of different grounds. The substrate, the reflectors arranged in an array on the first side of the substrate, and the ground plane on the second side of the substrate form a metamaterial structure with negative refractive index, which exhibits left-handed characteristics different from right-handed characteristics. Therefore, combined with the radiator with right-handed characteristics, the overall antenna structure can exhibit composite left-right characteristics, thereby increasing its operating bandwidth. In addition, parasitic capacitance is generated between two adjacent reflectors, which forms a parallel LC circuit with the reflector having inductive characteristics. At the resonance frequency, the reflectors arranged in an array have infinite impedance, so the electromagnetic waves emitted by the radiator can be reflected back to the radiator, and at the same time have an effect similar to that of a notch filter, thereby making the overall radiation field pattern face upward above the reflector array, further improving the antenna gain and directivity.

[0033] Figure 1A and Figure 1B are respectively the first-side plan view and the second-side plan view of the antenna structure 100 according to an embodiment of the present invention. The antenna structure 100 includes a substrate 110, a plurality of reflectors 120, a ground plane 130, a radiator 140, and a plurality of vias 150. The reflectors 120 are located on the first side of the substrate 110, the ground plane 130 and the radiator 140 are located on the second side of the substrate 110, and the vias 150 pass through the substrate 110 to respectively couple to the reflectors 120 and commonly couple to the ground plane 130.

[0034] The substrate 110 includes a liquid crystal polymer material, and its thickness is approximately 100 μm to 400 μm. The reflector 120 is a square patch and is arranged in an array of multiple rows and multiple columns on the first side of the substrate 110. Each reflector 120 has a length L 120 , and there is a gap G between adjacent reflectors 120 120 . In other embodiments, each reflector 120 can be a rectangular patch with different lengths and widths. Figure 1A and Figure 1B take the 3×3 reflectors 120 as an example, that is, the reflectors 120 are arranged in an array of three rows and three columns. In other variant embodiments, the antenna structure 100 can have different numbers and different arrangements of reflectors 120. The ground plane 130 is a rectangular patch and overlaps with the reflectors 120 in the normal direction of the substrate 110. Each reflector 120 can be electrically connected to the ground plane 130 through the via 150 passing through the substrate 110. The materials of the reflectors 120 and the ground plane 130 can be, for example, copper, silver, gold, platinum, nickel, tin metal, alloys of the above metals, and / or other suitable materials.

[0035] The radiator 140 is physically separated from the ground plane 130 and does not overlap with the reflector 120 in the normal direction of the substrate 110. Similar to the reflector 120 and the ground plane 130, the material of the radiator 140 can also be, for example, copper, silver, gold, platinum, nickel, tin metal, alloys of the above metals, and / or other suitable materials. The vias 150 are respectively located at the center of the reflector 120. However, the positions of the vias 150 can be correspondingly changed according to the number of the reflectors 120 and / or the size and pattern of the radiator 140, rather than being limited to the positions shown by Figure 1A and Figure 1B the positions shown

[0036] Figure 1C For Figure 1B the enlarged plan view of the radiator 140 shown. As Figure 1C shown, the radiator 140 is a monopole antenna, which has two radiation branches 141, 142, a signal feeding end 143 and a slotted hole 144, wherein the signal feeding end 143 is used to couple to an external terminal, and the slotted hole 144 is defined by the radiation branches 141 and 142, so that the radiator 140 can be used to excite at least two operating modes in different frequency bands. The ground plane 130 further has a notch 131, and the signal feeding end 143 is located in the notch 131, and there is a gap G between it and the ground plane 130 140 .

[0037] The radiation branch 141 has a straight section and a rectangular block section, wherein the length and width of the straight section are L1 141 and W1 141 , and the length and width of the rectangular block section are L2 141 and W2 141 . The radiation branch 142 has a single straight section, and its length and width are L 142 and W 142 . The signal feeding end 143 is square, and its length is L 143 . The slotted hole 144 is L-shaped and has a first section and a second section, wherein the length and width of the first section are L1 144 and W 144 , and the length and width of the second section are L2 144 and W 144 .

[0038] Figure 2A and Figure 2B respectively show the return loss simulation results of the antenna structure 100 of the embodiment of the present invention and the antenna structure of the comparative example. In the embodiment of the present invention, the length L 120 of the reflector 120 is 2.5 mm to 3.5 mm, and the length L1 of each section of the radiation branch 141 141, L2 141 and width W1 141 , W2 141 are 0.5 mm to 3.0 mm, 0.25 mm to 2.75 mm, 0.05 mm to 0.15 mm, 0.15 mm to 0.25 mm respectively, the length L 142 and width W 142 of the radiation branch 142 are 0.40 mm to 2.90 mm, 0.05 mm to 0.15 mm respectively. The length L1 141 of the radiation branch 141 142 and the length L Figure 1A and Figure 1B of the radiation branch 142 are approximately 0.23λ1 to 0.25λ1 and 0.23λ2 to 0.25λ2 respectively, where λ1 and λ2 are the wavelengths corresponding to the resonance frequencies of the first operating mode and the second operating mode respectively. The comparative example is Figure 2A and Figure 2B the antenna structure after removing all the reflectors 120 from the antenna structure 100. By comparing

[0039] Figure 3A This is the second side plan view of the antenna structure 300 of the embodiment of the present invention Figure 3A The shown antenna structure 300 includes a substrate 310, a plurality of reflectors 320, a ground plane 330, a radiator 340 and via holes 350. The reflectors 320 are located on the first side of the substrate 310. The ground plane 330 and the radiator 340 are located on the second side of the substrate 310 and are physically separated from each other. The via holes 350 pass through the substrate 310 to respectively couple the reflectors 320 and are commonly coupled to the ground plane 330 Figure 3A The antenna structure 300 of Figure 1A and Figure 1BThe difference in the antenna structure 100 is that, as Figure 3B Further shown, the radiator 340 has a straight signal feeding branch 341, a square radiation branch 342, a signal feeding end 343, and an L-shaped slotted hole 344. The two ends of the signal feeding branch 341 are respectively coupled to the radiation branch 342 and the signal feeding end 343. The signal feeding end 343 is located in the notch 331 of the ground plane 330 and is used to couple to an external terminal. The slotted hole 344 is defined by the radiation branch 342, such that the radiator 340 can be used to excite two operating modes. In other embodiments, the radiation branch 342 can be a rectangle with different length and width. The substrate 310, the reflector 320, the ground plane 330, and the via hole 350 are respectively similar to the substrate 110, the reflector 120, the ground plane 130, and the via hole 150 of the antenna structure 100, so the relevant descriptions can refer to the description of the aforementioned antenna structure 100.

[0040] Figure 4A and Figure 4B are respectively the first side plan view and the second side plan view of the antenna structure 400 according to an embodiment of the present invention. Figure 4A and Figure 4B The shown antenna structure 400 includes a substrate 410, a plurality of reflectors 420, ground planes 430A, 430B, radiators 440A, 440B, and via holes 450. The reflector 420, the ground plane 430A, and the radiator 440A are located on the first side of the substrate 410 and are electrically connected to each other. The ground plane 430B and the radiator 440B are located on the second side of the substrate 410 and are physically separated from each other. The ground planes 430A and 430B overlap in the normal direction of the substrate 410, and the via holes 450 pass through the substrate 410 to respectively couple to the reflector 420 and commonly couple to the ground plane 430B. Figure 4A and Figure 4B The difference between the antenna structure 400 and Figure 1A and Figure 1B the antenna structure 100 is that the radiators 440A, 440B form a dipole antenna, and as Figure 4C and Figure 4DAs further shown, radiator 440A has a straight grounding branch 441A, two radiating branches 442A, 443A, and an L-shaped slotted hole 444A, and radiator 440B has a straight signal feeding branch 441B, a signal feeding end 442B, two radiating branches 443B, 444B, and an L-shaped slotted hole 445B. In radiator 440A, two ends of the grounding branch 441A are respectively coupled to the ground plane 430A and the two radiating branches 442A, 443A. In radiator 440B, two ends of the signal feeding branch 441B are respectively coupled to the signal feeding end 442B and the two radiating branches 443B, 444B, and the signal feeding end 442B is located in the notch 431B of the ground plane 430B and is used to couple to an external terminal. The slotted hole 444A is defined by the radiating branches 442A, 443A, and the slotted hole 445B is defined by the radiating branches 443B, 444B, such that the radiators 440A, 440B can be used to jointly excite two operating modes. In addition, the grounding branch 441A and the signal feeding branch 441B can overlap in the normal direction of the substrate 410, and the ground planes 430A, 430B can be electrically connected to each other by additional vias (not shown in the figure) passing through the substrate 410. The substrate 410, the reflector 420, the ground plane 430B, and the via 450 are respectively similar to the substrate 110, the reflector 120, the ground plane 130, and the via 150 of the antenna structure 100, so the related descriptions can refer to the description of the aforementioned antenna structure 100.

[0041] Figure 5A This is a second side plan view of the antenna structure 500 according to an embodiment of the present invention. Figure 5A The shown antenna structure 500 includes a substrate 510, a plurality of reflectors 520, a ground plane 530, a radiator 540, and a via 550, wherein the reflector 520 is located on the first side of the substrate 510, the ground plane 530 and the radiator 540 are located on the second side of the substrate 510, and the via 550 passes through the substrate 510 to respectively couple to the reflector 520 and jointly couple to the ground plane 530. Figure 5A The antenna structure 500 of Figure 1A 、 Figure 1B The difference between the antenna structure 100 of Figure 5BFurther shown, the radiator 540 has a signal feeding branch 541, a signal feeding terminal 542, a grounding branch 543, a radiation branch 544, and an L-shaped slotted hole 545. One ends of the signal feeding branch 541 and the grounding branch 543 are coupled to the radiation branch 544. The other end of the signal feeding branch 541 is coupled to the signal feeding terminal 542. The other end of the grounding branch 543 is coupled to the ground plane 530. The signal feeding terminal 542 is located in the notch 531 of the ground plane 530 and is used to couple to an external terminal. The radiation end of the radiation branch 544 is composed of two radiation branches 546 and 547, and the slotted hole 545 is defined by the radiation branches 546 and 547, such that the radiator 540 can be used to excite two operating modes. The substrate 510, the reflector 520, the ground plane 530, and the via hole 550 are respectively similar to the substrate 110, the reflector 120, the ground plane 130, and the via hole 150 of the antenna structure 100. Therefore, the relevant descriptions can refer to the description of the aforementioned antenna structure 100.

[0042] Figure 6 It is the first side plan view of the antenna structure 600 according to an embodiment of the present invention. Figure 6 The shown antenna structure 600 includes a substrate 610, a plurality of reflectors 620, a ground plane 630, a radiator 640, and via holes 650. The reflectors 620 are located on the first side of the substrate 610. The ground plane 630 and the radiator 640 are located on the second side of the substrate 610 and are physically separated from each other. The via holes 650 pass through the substrate 610 to respectively couple to the reflectors 620 and commonly couple to the ground plane 630. Figure 6 The antenna structure 600 of Figure 1A and Figure 1B The difference between the antenna structure 100 of Figure 6 shown is that, as

[0043] Figure 7 It is the first side plan view of the antenna structure 700 according to an embodiment of the present invention. Figure 7 The shown antenna structure 700 includes a substrate 710, a plurality of reflectors 720, a ground plane 730, a radiator 740, and via holes 750. The reflectors 720 are located on the first side of the substrate 710. The ground plane 730 and the radiator 740 are located on the second side of the substrate 710 and are physically separated from each other. The via holes 750 pass through the substrate 710 to respectively couple to the reflectors 720 and commonly couple to the ground plane 730. Figure 7 The antenna structure 700 of Figure 1A and Figure 1B The difference between the antenna structure 100 ofFigure 7 As shown, each reflector 720 is a circular plate. The substrate 710, the ground plane 730, the radiator 740, and the via hole 750 are respectively similar to the substrate 110, the ground plane 130, the radiator 140, and the via hole 150 of the antenna structure 100. Therefore, the relevant descriptions can refer to the description of the aforementioned antenna structure 100.

[0044] Figure 8 It is the first side plan view of the antenna structure 800 according to an embodiment of the present invention. Figure 8 The shown antenna structure 800 includes a substrate 810, a plurality of reflectors 820, a ground plane 830, a radiator 840, and via holes 850. Among them, the reflector 820 is located on the first side of the substrate 810. The ground plane 830 and the radiator 840 are located on the second side of the substrate 810 and are physically separated from each other. And the via holes 850 pass through the substrate 810 to respectively couple to the reflector 820 and commonly couple to the ground plane 830. Figure 8 The antenna structure 800 of Figure 1A and Figure 1B The difference between the antenna structure 800 and Figure 8 the antenna structure 100 of

[0045] Figure 9A It is the first side plan view of the antenna structure 900 according to another embodiment of the present invention. The antenna structure 900 includes a substrate 910, a plurality of reflectors 920, a ground plane 930, a radiator 940, and a plurality of via holes 950. Compared with the substrate 110 of the antenna structure 100, the substrate 910 is a flexible substrate that can be bent, and it has a planar portion 910A, a bendable portion 910B, and a protrusion portion 910C. The reflector 920, the ground plane 930, the radiator 940, and the via holes 950 can be respectively similar to the reflector 120, the ground plane 130, the radiator 140, and the via holes 150 of the antenna structure 100.

[0046] Figure 9B and Figure 9C are respectively the three-dimensional view and the side view of the bent antenna structure 900. As Figure 9B and Figure 9C shown, after the substrate 910 is bent, the planar portion 910A is substantially perpendicular to the protrusion portion 910C. The ground plane 930 extends from the planar portion 910A through the bendable portion 910B to the protrusion portion 910C. The reflector 920 and the via holes 950 are located on the planar portion 910A, and the radiator 940 is located on the protrusion portion 910C.

[0047] Although the present invention has been disclosed above by way of examples, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to that defined by the claims.

Claims

1. An antenna structure, characterized in that, Comprising: A substrate having opposite first and second sides, the substrate comprising a liquid crystal polymer material; A plurality of reflectors located on the first side of the substrate, the reflectors arranged in an array; A first ground plane located on the second side of the substrate, the first ground plane overlapping the reflectors in the normal direction of the substrate; A first radiator located on the second side of the substrate, the first radiator not overlapping the reflectors in the normal direction of the substrate, and the first radiator having a slotted hole defined by a first radiation branch and a second radiation branch, the slotted hole being used to excite at least two operating modes of different frequency bands, the length of the first radiation branch being 0.23λ1 to 0.25λ1, and the length of the second radiation branch being 0.23λ2 to 0.25λ2, where λ1 and λ2 are the wavelengths corresponding to the first resonance frequency and the second resonance frequency of the operating modes respectively; and A plurality of vias respectively passing through the substrate, each of the vias coupling the reflectors and the first ground plane on the first and second sides of the substrate respectively; Wherein, the substrate has a planar portion and a protrusion portion, the planar portion is substantially perpendicular to the protrusion portion, and the reflectors and the first radiator are respectively located on the planar portion and the protrusion portion.

2. The antenna structure according to claim 1, characterized in that The first ground plane defines a notch, and the first radiator has a signal feeding end located in the notch.

3. The antenna structure according to claim 1, wherein, The slotted hole is an L-shaped slotted hole.

4. The antenna structure according to claim 1, wherein The first radiator comprises: A signal feeding end for coupling an external terminal; A signal feeding branch coupling the signal feeding end; And A radiation branch coupling the signal feeding branch and defining the slotted hole.

5. The antenna structure according to claim 4, wherein, The radiation branch is square or rectangular.

6. The antenna structure according to claim 1, characterized in that, Further comprising: A second ground plane located on the first side of the substrate and electrically connected to the first ground plane; and A second radiator located on the first side of the substrate and coupled to the second ground plane, the second radiator and the first radiator forming a dipole antenna.

7. The antenna structure according to claim 6, characterized in that, The signal feeding branch of the first radiator and the grounding branch of the second radiator overlap in the normal direction of the substrate.

8. The antenna structure according to claim 1, characterized in that, The first radiator comprises: A signal feeding end for coupling an external terminal; A signal feeding branch coupling the signal feeding end; A grounding branch coupling the first ground plane; And A radiation branch coupling the signal feeding branch and the grounding branch and defining the slotted hole.

9. The antenna structure according to claim 1, wherein Each of the reflectors is a rectangular frame or rectangular, cross-shaped or circular.

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