Antenna structure

Abstract

The present invention discloses an antenna structure, comprising: a first radiating portion, a second radiating portion, a third radiating portion, a fourth radiating portion, a fifth radiating portion, and a dielectric substrate. The first radiating portion has a positive feeding point. The second radiating portion is coupled to the first radiating portion. The third radiating portion has a negative feeding point. The fourth radiating portion is coupled to the third radiating portion. The fifth radiating portion is in a floating state. The dielectric substrate has a first surface and a second surface opposite to each other. The first radiating portion and the third radiating portion are both arranged on the first surface of the dielectric substrate. The second radiating portion, the fourth radiating portion, and the fifth radiating portion are all arranged on the second surface of the dielectric substrate.

Description

Technical Field

[0001] The invention relates to an antenna structure, in particular to a small-size, wide-band antenna structure. Background Art

[0002] With the development of mobile communication technology, mobile devices have become increasingly popular in recent years, such as portable computers, mobile phones, multimedia players and other hybrid portable electronic devices. In order to meet people's needs, mobile devices usually have wireless communication functions. Some cover long-distance wireless communication ranges, such as mobile phones using 2G, 3G, LTE (Long Term Evolution) systems and the 700MHz, 850MHz, 900MHz, 1800MHz, 1900MHz, 2100MHz, 2300MHz and 2500MHz frequency bands used for communication, while some cover short-distance wireless communication ranges, such as Wi-Fi, Bluetooth systems use 2.4GHz, 5.2GHz and 5.8GHz frequency bands for communication.

[0003] Antennas are indispensable components in the field of wireless communications. If the bandwidth of an antenna used to receive or transmit signals is insufficient, the communication quality of a mobile device can be easily degraded. Therefore, how to design a small-sized, wide-bandwidth antenna element is an important issue for antenna designers. Summary of the invention

[0004] In a preferred embodiment, the present invention proposes an antenna structure, comprising: a first radiating portion having a positive feeding point; a second radiating portion coupled to the first radiating portion; a third radiating portion having a negative feeding point; a fourth radiating portion coupled to the third radiating portion; a fifth radiating portion, wherein the fifth radiating portion is in a floating state; and a dielectric substrate having a first surface and a second surface opposite to each other; wherein the first radiating portion and the third radiating portion are both arranged on the first surface of the dielectric substrate; wherein the second radiating portion, the fourth radiating portion, and the fifth radiating portion are all arranged on the second surface of the dielectric substrate.

[0005] In some embodiments, the antenna structure also includes: a first conductive through-element penetrating the dielectric substrate, wherein the second radiating portion is coupled to the first radiating portion via the first conductive through-element; and a second conductive through-element penetrating the dielectric substrate, wherein the fourth radiating portion is coupled to the third radiating portion via the second conductive through-element.

[0006] In some embodiments, the first radiation portion is in a straight strip shape, and the second radiation portion is in a longer L shape.

[0007] In some embodiments, the third radiating portion is in a U-shape, and the fourth radiating portion is in a shorter L-shape.

[0008] In some embodiments, the fifth radiating portion is in a T-shape and includes a wider portion and a narrower portion.

[0009] In some embodiments, vertical projections of the positive feeding point and the negative feeding point on the second surface of the dielectric substrate are both located within the wider portion of the fifth radiating portion.

[0010] In some embodiments, the antenna structure covers a first frequency band and a second frequency band, the first frequency band is between 2400 MHz and 2500 MHz, and the second frequency band is between 5150 MHz and 5850 MHz.

[0011] In some embodiments, a total length of the first radiating portion and the second radiating portion is less than or equal to 0.25 times the wavelength of the first frequency band.

[0012] In some embodiments, a total length of the third radiation portion and the fourth radiation portion is less than or equal to 0.25 times the wavelength of the first frequency band.

[0013] In some embodiments, the antenna structure also includes: a coaxial cable, including a center conductor and a conductor shell, wherein the center conductor is coupled to the positive feed point, and the conductor shell is coupled to the negative feed point; wherein the length of the coaxial cable is less than or equal to 50 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A front view of an antenna structure according to an embodiment of the present invention;

[0015] Figure 2 A back view of an antenna structure according to an embodiment of the present invention;

[0016] Figure 3 A schematic diagram of a coaxial cable according to an embodiment of the present invention;

[0017] Figure 4 A voltage standing wave ratio diagram of an antenna structure according to an embodiment of the present invention;

[0018] Figure 5 FIG. 1 is a voltage standing wave ratio diagram of the antenna structure according to an embodiment of the present invention when the antenna structure is held in the hand of a user.

[0019] Explanation of symbols

[0020] 100: Mobile device

[0021] 110: First radiation part

[0022] 111: first end of the first radiation portion

[0023] 112: second end of the first radiation portion

[0024] 120: Second radiation part

[0025] 121: first end of the second radiation portion

[0026] 122: second end of the second radiation portion

[0027] 130: The third radiation

[0028] 131: first end of the third radiation portion

[0029] 132: second end of the third radiation portion

[0030] 140: The fourth radiation

[0031] 141: first end of the fourth radiation portion

[0032] 142: second end of the fourth radiation portion

[0033] 150: Fifth Radiation Department

[0034] 151: first end of the fifth radiation portion

[0035] 152: second end of the fifth radiation portion

[0036] 153: The third end of the fifth radiation portion

[0037] 154: The wider part of the fifth radiation portion

[0038] 155: Narrower part of the fifth radiation

[0039] 161: first conductive through element

[0040] 162: second conductive through element

[0041] 170: Dielectric substrate

[0042] 180: Coaxial cable

[0043] 181: Center conductor

[0044] 182: Conductor shell

[0045] 190:Signal source

[0046] D1: Spacing

[0047] E1: The first surface of the dielectric substrate

[0048] E2: Second surface of dielectric substrate

[0049] FB1: First frequency band

[0050] FB2: Second frequency band

[0051] FP: Positive Feed Point

[0052] FN: Negative Feed Point

[0053] L1,L2,L51,L52,LC,LT:Length

[0054] P1: First vertical projection

[0055] P2: Second vertical projection

[0056] W1,W2,W3,W4,W51,W52,WT: Width DETAILED DESCRIPTION

[0057] In order to make the purpose, features and advantages of the present invention more clearly understood, specific embodiments of the present invention are given below with reference to the accompanying drawings for detailed description as follows.

[0058] Certain words are used in the specification and claims to refer to specific components. It should be understood by those skilled in the art that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. The words "include" and "comprise" mentioned throughout the specification and claims are open-ended terms and should be interpreted as "include but not limited to". The word "substantially" means that within an acceptable error range, those skilled in the art can solve the technical problem and achieve the basic technical effect within a certain error range. In addition, the word "coupled" in this specification includes any direct and indirect electrical connection means. Therefore, if the text describes a first device coupled to a second device, it means that the first device can be directly electrically connected to the second device, or indirectly electrically connected to the second device via other devices or connection means.

[0059] Figure 1 FIG. 1 is a front view of an antenna structure 100 according to an embodiment of the present invention. Figure 2 1 is a back view of the antenna structure 100 according to an embodiment of the present invention (compared to the front view, the antenna structure 100 is flipped 180 degrees). The antenna structure 100 can be applied to a mobile device, such as a joystick, a smart phone, a tablet computer, or a notebook computer. Figure 1 In the embodiment of the present invention, the antenna structure 100 at least includes: a first radiation element 110, a second radiation element 120, a third radiation element 130, a fourth radiation element 140, a fifth radiation element 150, and a dielectric substrate 170, wherein the first radiation element 110, the second radiation element 120, the third radiation element 130, the fourth radiation element 140, and the fifth radiation element 150 can be made of metal materials, such as copper, silver, aluminum, iron, or alloys thereof.

[0060] The dielectric substrate 170 may be a FR4 (Flame Retardant 4) substrate, a printed circuit board (PCB), or a flexible circuit board (FCB). The dielectric substrate 170 has a first surface E1 and a second surface E2 opposite to each other, wherein the first radiating portion 110 and the third radiating portion 130 may be disposed on the first surface E1 of the dielectric substrate 170, and the second radiating portion 120, the fourth radiating portion 140, and the fifth radiating portion 150 may be disposed on the second surface E2 of the dielectric substrate 170.

[0061] The first radiating portion 110 may be substantially in the shape of a straight strip. Specifically, the first radiating portion 110 has a first end 111 and a second end 112, wherein a positive feeding point FP is located at the first end 111 of the first radiating portion 110. The positive feeding point FP may also be coupled to a positive electrode of a signal source 190. For example, the signal source 190 may be a radio frequency (RF) module, which may be used to excite the antenna structure 100.

[0062] The second radiating portion 120 may be substantially in a long L-shape, which may be partially perpendicular and partially parallel to the first radiating portion 110. In detail, the second radiating portion 120 has a first end 121 and a second end 122, wherein the first end 121 of the second radiating portion 120 is coupled to the second end 112 of the first radiating portion 110, and the second end 122 of the second radiating portion 120 is an open end. The first end 111 of the first radiating portion 110 and the second end 122 of the second radiating portion 120 may extend substantially in the same direction.

[0063] In some embodiments, the antenna structure 100 further includes a first conductive via element 161. For example, the first conductive via element 161 may be adjacent to a corner of the dielectric substrate 170. The first conductive via element 161 may penetrate the dielectric substrate 170 and may be coupled between the second end 112 of the first radiating portion 110 and the first end 121 of the second radiating portion 120. It should be noted that the term "adjacent" or "adjacent" in this specification may refer to a distance between two corresponding elements being less than a predetermined distance (e.g., 5 mm or shorter), and may also include a situation where two corresponding elements are in direct contact with each other (i.e., the aforementioned distance is shortened to 0).

[0064] The third radiating portion 130 may be substantially U-shaped. Specifically, the third radiating portion 130 has a first end 131 and a second end 132, wherein a negative feeding point FN is located at the first end 131 of the third radiating portion 130. The negative feeding point FN is separated from and opposite to the positive feeding point FP, and may also be coupled to the negative electrode of the signal source 190. The first end 131 and the second end 132 of the third radiating portion 130 may extend substantially in the same direction.

[0065] The fourth radiating portion 140 may be substantially in a shorter L-shape (which is shorter than the second radiating portion 120). Specifically, the fourth radiating portion 140 has a first end 141 and a second end 142, wherein the first end 141 of the fourth radiating portion 140 is coupled to the second end 132 of the third radiating portion 130, and the second end 142 of the fourth radiating portion 140 is an open end. In some embodiments, the fourth radiating portion 140 has a vertical projection on the first surface E1 of the dielectric substrate 170, and the vertical projection at least partially overlaps with the third radiating portion 130.

[0066] In some embodiments, the antenna structure 100 further includes a second conductive through-element 162. For example, the second conductive through-element 162 may be adjacent to a lower edge of the dielectric substrate 170. The second conductive through-element 162 may penetrate the dielectric substrate 170 and may be coupled between the second end 132 of the third radiating portion 130 and the first end 141 of the fourth radiating portion 140.

[0067] The fifth radiating portion 150 may be substantially T-shaped. Specifically, the fifth radiating portion 150 has a first end 151, a second end 152, and a third end 153, which are three open ends. The first end 151 and the second end 152 of the fifth radiating portion 150 may extend in opposite directions away from each other. It should be noted that the fifth radiating portion 150 is in a floating state, and it is not in direct contact with any other radiating portion. The fifth radiating portion 150 includes a wider portion 154 and a narrower portion 155. In some embodiments, the positive feed point FP has a first vertical projection P1 on the second surface E2 of the dielectric substrate 170, and the negative feed point FN has a second vertical projection P2 on the second surface E2 of the dielectric substrate 170. The first vertical projection P1 and the second vertical projection P2 are both located inside the wider portion 154 of the fifth radiating portion 150 , wherein the first vertical projection P1 is adjacent to the first end 151 of the fifth radiating portion 150 , and the second vertical projection P2 is adjacent to the second end 152 of the fifth radiating portion 150 .

[0068] In some embodiments, the antenna structure 100 further includes a coaxial cable 180 . Figure 3 FIG. 1 is a schematic diagram showing a coaxial cable 180 according to an embodiment of the present invention. Figure 3 In the embodiment, the coaxial cable 180 includes a central conductive line 181 and a conductive housing 182, wherein the positive pole of the signal source 190 can be coupled to the positive feeding point FP via the central conductive line 181, and the negative pole of the signal source 190 can be coupled to the negative feeding point FN via the conductive housing 182.

[0069] Figure 4 2 is a graph showing the voltage standing wave ratio (VSWR) of the antenna structure 100 according to an embodiment of the present invention, wherein the horizontal axis represents the operating frequency (MHz) and the vertical axis represents the voltage standing wave ratio. Figure 4 According to the measurement results, when excited by the signal source 190, the antenna structure 100 will cover a first frequency band FB1 and a second frequency band FB2. For example, the first frequency band FB1 may be between 2400MHz and 2500MHz, and the second frequency band FB2 may be between 5150MHz and 5850MHz. Therefore, the antenna structure 100 will at least support WLAN (Wireless Wide Area Network) 2.4GHz / 5GHz broadband operation.

[0070] In terms of antenna principle, the first radiating portion 110, the second radiating portion 120, the third radiating portion 130, and the fourth radiating portion 140 can excite a fundamental resonant mode to form the aforementioned first frequency band FB1. The first radiating portion 110, the second radiating portion 120, the third radiating portion 130, and the fourth radiating portion 140 can also excite a higher-order resonant mode (double frequency effect) to form the aforementioned second frequency band FB2. In addition, the addition of the fifth radiating portion 150 can increase the coupling amount between the first radiating portion 110 and the third radiating portion 130. According to actual measurement results, this design can be used to fine-tune the impedance matching of the antenna structure 100. Since there is no need to design a larger system ground plane, the antenna structure 100 can not only reduce its overall size, but also support its required broadband operation.

[0071] In some embodiments, the element dimensions of the antenna structure 100 may be as follows. The total length L1 of the first radiating portion 110 and the second radiating portion 120 may be less than or equal to 0.25 times the wavelength (λ / 4) of the first frequency band FB1 of the antenna structure 100. The width W1 of the first radiating portion 110 may be between 1 mm and 2 mm. The width W2 of the second radiating portion 120 may be between 1 mm and 2 mm. The total length L2 of the third radiating portion 130 and the fourth radiating portion 140 may be less than or equal to 0.25 times the wavelength (λ / 4) of the first frequency band FB1 of the antenna structure 100. The width W3 of the third radiating portion 130 may be between 1 mm and 2 mm. The width W4 of the fourth radiating portion 140 may be between 1 mm and 2 mm. In the fifth radiating portion 150, the ratio (W51 / W52) of the width W51 of the wider portion 154 and the width W52 of the narrower portion 155 may be approximately equal to 3, and the ratio (L51 / L52) of the length L51 of the wider portion 154 and the length L52 of the narrower portion 155 may be approximately equal to 0.25. The distance D1 between the second end 122 of the second radiating portion 120 and the first end 141 of the fourth radiating portion 140 may be between 2 mm and 3 mm. The thickness of the dielectric substrate 170 (i.e., the distance between the first surface E1 and the second surface E2) may be approximately 0.4 mm. The total length LT of the antenna structure 100 may be approximately 20 mm, and the total width WT of the antenna structure 100 may be approximately 6 mm. In order to reduce transmission loss, the length LC of the coaxial cable 180 must be less than or equal to 50 mm. The above range of component sizes is obtained based on multiple experimental results, which helps to optimize the operating bandwidth and impedance matching of the antenna structure 100.

[0072] Figure 5 1 is a graph showing the voltage standing wave ratio of the antenna structure 100 according to an embodiment of the present invention when it is held in the hand of a user, wherein the horizontal axis represents the operating frequency (MHz) and the vertical axis represents the voltage standing wave ratio. Figure 5 According to the measurement results, even if the antenna structure 100 is very close to the human body, the operating frequency will not be significantly shifted, so the antenna structure 100 will be able to provide sufficient reliability.

[0073] The present invention proposes a novel antenna structure. Compared with the traditional design, the present invention has at least the advantages of small size, wide bandwidth, low manufacturing cost, and high reliability, so it is very suitable for application in various mobile communication devices.

[0074] It is worth noting that the above-mentioned element size, element shape, and frequency range are not limiting conditions of the present invention. Antenna designers can adjust these settings according to different needs. The antenna structure of the present invention is not limited to Figure 1 to Figure 5 The present invention may only include Figure 1 to Figure 5 In other words, not all the features shown in the figures need to be implemented in the antenna structure of the present invention at the same time.

[0075] In the present specification and claims, ordinal numbers, such as "first", "second", "third", etc., have no sequential relationship with each other, and are only used to distinguish two different components with the same name.

[0076] Although the present invention is disclosed in conjunction with the above preferred embodiments, it is not intended to limit the scope of the present invention. Anyone familiar with this technology may make slight changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the definition of the attached claims.

Claims

1. An antenna structure, characterized in that: include: A first radiating portion having a positive feeding point; A second radiation portion, coupled to the first radiation portion; A third radiating portion having a negative feed point; a fourth radiation portion, coupled to the third radiation portion; A fifth radiating portion, wherein the fifth radiating portion is in a floating state; as well as A dielectric substrate having a first surface and a second surface opposite to each other; The first radiation portion and the third radiation portion are both disposed on the first surface of the dielectric substrate; The second radiation portion, the fourth radiation portion and the fifth radiation portion are all disposed on the second surface of the dielectric substrate. The fifth radiating portion is T-shaped and includes a wider portion and a narrower portion. The vertical projections of the positive feeding point and the negative feeding point on the second surface of the dielectric substrate are both located within the wider portion of the fifth radiating portion.

2. The antenna structure according to claim 1, further comprising: A first conductive through-element penetrates the dielectric substrate, wherein the second radiating portion is coupled to the first radiating portion via the first conductive through-element; as well as The second conductive through-element penetrates the dielectric substrate, wherein the fourth radiation portion is coupled to the third radiation portion via the second conductive through-element. 3 . The antenna structure as claimed in claim 1 , wherein the first radiating portion is in a straight strip shape, and the second radiating portion is in a longer L shape. 4 . The antenna structure as claimed in claim 1 , wherein the third radiating portion is in a U-shape, and the fourth radiating portion is in a shorter L-shape. 5 . The antenna structure as claimed in claim 1 , wherein the antenna structure covers a first frequency band and a second frequency band, the first frequency band is between 2400 MHz and 2500 MHz, and the second frequency band is between 5150 MHz and 5850 MHz. 6 . The antenna structure as claimed in claim 5 , wherein a total length of the first radiating portion and the second radiating portion is less than or equal to 0.25 times the wavelength of the first frequency band. 7 . The antenna structure as claimed in claim 5 , wherein a total length of the third radiating portion and the fourth radiating portion is less than or equal to 0.25 times the wavelength of the first frequency band.

8. The antenna structure according to claim 1, further comprising: A coaxial cable, comprising a center conductor and a conductor housing, wherein the center conductor is coupled to the positive feed point, and the conductor housing is coupled to the negative feed point; The length of the coaxial cable is less than or equal to 50 mm.

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