CN110911824B

CN110911824B - Antenna structure

Info

Publication number: CN110911824B
Application number: CN201811087114.9A
Authority: CN
Inventors: 黄钧麟; 黄健庭
Original assignee: Wistron Neweb Corp
Current assignee: Wistron Neweb Corp
Priority date: 2018-09-18
Filing date: 2018-09-18
Publication date: 2021-08-17
Anticipated expiration: 2038-09-18
Also published as: CN110911824A

Abstract

An antenna structure. The antenna structure comprises a ground plane, a dielectric substrate, a first radiation part, a second radiation part, a third radiation part and a fourth radiation part; the dielectric substrate is provided with a first surface and a second surface, and the second surface of the dielectric substrate is adjacent to the ground plane; the first radiation part is coupled to a signal source; the third radiation part and the fourth radiation part are both coupled between the first radiation part and the second radiation part; the third radiation part is provided with a first gap and a second gap; the fourth radiation part is provided with a third gap and a fourth gap; the first radiation part, the second radiation part, the third radiation part and the fourth radiation part form a ring structure; a fifth gap is formed between the first radiation part and the third radiation part; a sixth gap is formed between the first radiation part and the fourth radiation part; a seventh gap is formed between the second radiation part and the third radiation part, and an eighth gap is formed between the second radiation part and the fourth radiation part. The invention has the advantages of high gain, low loss, light and thin structure, low manufacturing cost and the like.

Description

Antenna structure

Technical Field

The present invention relates to an Antenna Structure (Antenna Structure), and more particularly, to a High Gain (High Gain) Antenna Structure (Antenna Structure).

Background

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 portable electronic devices with mixed functionality. To meet the demand of people, mobile devices generally have a function of wireless communication. Some cover long-range wireless communication ranges, such as: the mobile phone uses 2G, 3G, LTE (Long Term Evolution) system and its used frequency bands of 700MHz, 850MHz, 900MHz, 1800MHz, 1900MHz, 2100MHz, 2300MHz and 2500MHz for communication, while some cover short-distance wireless communication ranges, for example: Wi-Fi and Bluetooth systems use frequency bands of 2.4GHz, 5.2GHz, and 5.8GHz for communication.

An Antenna (Antenna) is an indispensable element in the field of wireless communication. If the Gain (Gain) of the antenna for receiving or transmitting signals is insufficient, it is easy to cause degradation of the communication quality of the device. Therefore, how to design an antenna element with high gain is an important issue for an antenna designer.

Therefore, it is desirable to provide an antenna structure to solve the above problems.

Disclosure of Invention

In a preferred embodiment, the present invention provides an antenna structure, comprising: a ground plane; a dielectric substrate having a first surface and a second surface, wherein the second surface of the dielectric substrate is adjacent to the ground plane; a first radiation part, which is coupled to a signal source; a second radiation part; a third radiation part coupled between the first radiation part and the second radiation part, wherein the third radiation part has a first gap and a second gap; and a fourth radiation part coupled between the first radiation part and the second radiation part, wherein the fourth radiation part has a third gap and a fourth gap; wherein the first radiation part, the second radiation part, the third radiation part and the fourth radiation part are all arranged on the first surface of the dielectric substrate; wherein the first radiation part, the second radiation part, the third radiation part and the fourth radiation part form a ring structure together; wherein a fifth gap is formed between the first radiation part and the third radiation part, a sixth gap is formed between the first radiation part and the fourth radiation part, a seventh gap is formed between the second radiation part and the third radiation part, and an eighth gap is formed between the second radiation part and the fourth radiation part.

In some embodiments, the first radiating portion and the second radiating portion each substantially exhibit a square shape.

In some embodiments, the third radiating portion and the fourth radiating portion each substantially exhibit a rectangular shape.

In some embodiments, the first notch, the second notch, the third notch, the fourth notch, the fifth notch, the sixth notch, the seventh notch, and the eighth notch each substantially have a straight bar shape.

In some embodiments, each of the first radiating portion, the second radiating portion, the third radiating portion, and the fourth radiating portion has a first edge and a third edge opposite to each other, and a second edge and a fourth edge opposite to each other.

In some embodiments, the antenna structure further comprises: a first matching branch, wherein the signal source is coupled to a first connection point on the first edge of the first radiation portion via the first matching branch; and a second matching branch coupled to a second connection point on the first edge of the first radiating portion; wherein the second connection point is different from the first connection point.

In some embodiments, the second edge of the second radiating portion is coupled to the second edge of the first radiating portion via the third radiating portion, and the fourth edge of the second radiating portion is coupled to the fourth edge of the first radiating portion via the fourth radiating portion.

In some embodiments, the first notch is located at the second edge of the third radiating portion, the second notch is located at the fourth edge of the third radiating portion, the third notch is located at the second edge of the fourth radiating portion, and the fourth notch is located at the fourth edge of the fourth radiating portion.

In some embodiments, the fifth notch is located between the second edge of the first radiating portion and the fourth edge of the third radiating portion, the sixth notch is located between the fourth edge of the first radiating portion and the second edge of the fourth radiating portion, the seventh notch is located between the second edge of the second radiating portion and the fourth edge of the third radiating portion, and the eighth notch is located between the fourth edge of the second radiating portion and the second edge of the fourth radiating portion.

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

In some embodiments, the first frequency band is generated by excitation of the first radiation portion, the second radiation portion, the third radiation portion, and the fourth radiation portion, and the second frequency band is generated by excitation of the first radiation portion and the second radiation portion.

In some embodiments, a first distance is between the first edge of the first radiating portion and the third edge of the second radiating portion, or between the second edge of the third radiating portion and the fourth edge of the fourth radiating portion, and the first distance is calculated according to the following equation:

wherein "D₁"represents the first distance," c "represents the speed of light," f₁"represents the center frequency of the first frequency band,". epsilon._e"represents an equivalent dielectric constant between about 1 and 1.3," k "represents a first compensation constant between about 0.1 and 0.5, and" h "represents a spacing between the first surface and the ground plane.

In some embodiments, a second distance is between the first edge and the third edge of the first radiating portion, or between the first edge and the third edge of the second radiating portion, and the second distance is calculated according to the following equation:

wherein "D₂"represents the second distance," c "represents the speed of light," f₂"represents the center frequency of the second frequency band,". epsilon._e"represents an equivalent dielectric constant between about 1 and 1.3," k "represents a first compensation constant between about 0.1 and 0.5, and" h "represents a spacing between the first surface and the ground plane.

In some embodiments, the length of the first matching branch is calculated according to the following equation:

wherein "M₁"represents the length of the first matching branch," c "represents the speed of light," f₁"represents the center frequency of the first frequency band,". epsilon._e"represents an equivalent dielectric constant of between about 1 and 1.3, and" m "represents a second compensation constant of between about 1 and 1.5.

In some embodiments, the length of the second matching branch is calculated according to the following equation:

wherein "M₂"represents the length of the second matching branch," c "represents the speed of light," f₂"represents the center frequency of the second frequency band,". epsilon._e"represents an equivalent dielectric constant of between about 1 and 1.3, and" m "represents a second compensation constant of between about 1 and 1.5.

In some embodiments, a third distance is between the first edge and the third edge of the third radiating portion, or between the first edge and the third edge of the fourth radiating portion, and the third distance is calculated according to the following equation:

wherein "D₃"represents the third distance," c "represents the speed of light," f₂"represents the center frequency of the second frequency band,". epsilon._e"represents an equivalent dielectric constant of between about 1 and 1.3, and" m "represents a second compensation constant of between about 1 and 1.5.

In some embodiments, a fourth distance is between the second notch and the first edge of the first radiating portion, or between the third notch and the first edge of the first radiating portion, and the fourth distance is calculated according to the following equation:

wherein "D₄"represents the fourth distance," c "represents the speed of light," f₁"represents the center frequency of the first frequency band,". epsilon._e"represents an equivalent dielectric constant between about 1 and 1.3," k "represents a first compensation constant between about 0.1 and 0.5, and" h "represents a spacing between the first surface and the ground plane.

In some embodiments, a fifth distance is between the first edge of the first radiating portion and the first edge of the second radiating portion, and the fifth distance is substantially equal to the third distance.

In some embodiments, a gap length of each of the first gap, the second gap, the third gap, the fourth gap, the fifth gap, the sixth gap, the seventh gap, and the eighth gap is calculated according to the following equation:

wherein "S_L"represents the gap length," c "represents the speed of light," f₂"represents the center frequency of the second frequency band, and" ε_e"represents an equivalent dielectric constant of between about 1 and 1.3.

In some embodiments, a notch width of each of the first notch, the second notch, the third notch, the fourth notch, the fifth notch, the sixth notch, the seventh notch, and the eighth notch is less than or equal to 1 mm.

Compared with the conventional design, the antenna structure of the present invention has at least the advantages of high gain, low loss, light and thin structure, low manufacturing cost, etc., so that the antenna structure is suitable for various communication devices.

Drawings

Fig. 1A is a top view of an antenna structure according to an embodiment of the invention.

Fig. 1B is a perspective view of an antenna structure according to an embodiment of the invention.

Fig. 2A is a diagram illustrating a radiation pattern of the antenna structure in a first frequency band according to an embodiment of the invention.

Fig. 2B is a diagram illustrating a radiation pattern of the antenna structure in a second frequency band according to an embodiment of the invention.

Fig. 3 is a top view of an antenna structure according to another embodiment of the invention.

Description of the main element symbols:

100. 300 antenna structure

105 ground plane

110 dielectric substrate

120 first radiation part

121 first edge of first radiating portion

122 second edge of the first radiating portion

123 third edge of the first radiating portion

124 fourth edge of the first radiating portion

130 second radiation part

131 first edge of the second radiating portion

132 second edge of the second radiating portion

133 third edge of the second radiation part

134 fourth edge of the second radiating portion

140 third radiation part

141 first edge of third radiating portion

142 second edge of the third radiating portion

143 third edge of the third radiating portion

144 fourth edge of the third radiating portion

150 fourth radiation part

151 first edge of fourth radiating part

152 second edge of the fourth radiating portion

153 third edge of fourth radiating portion

154 fourth edge of the fourth radiating portion

161 first notch

162 second notch

163 third gap

164 fourth gap

165 fifth gap

166 sixth notch

167 the seventh gap

168 eighth notch

170 first matching branch

171 first end of a first matching branch

172 second end of first matching branch

180 second matching branch

181 first end of second matching branch

182 second end of the second matching branch

191 a first corner notch area

192 second corner notch area

193 third corner gap area

194 fourth corner notch area

195 hollow part of ring structure

199 Signal Source

CP1 first connection point

CP2 second connection point

D₁First distance

D₂Second distance

D₃Third distance

D₄A fourth distance

D₅A fifth distance

DG separation distance

First surface of E1 dielectric substrate

Second surface of E2 dielectric substrate

M₁Length of the first matching branch

M₂Length of the second matching branch

S_LLength of gap

S_WWidth of gap

X X axle

Y Y axle

Z Z axle

Detailed Description

In order to make the objects, features and advantages of the present invention comprehensible, specific embodiments accompanied with figures are described in detail below.

Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. The present specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The term "substantially" means within an acceptable error range, within which a person skilled in the art can solve the technical problem to achieve the basic technical result. In addition, the term "coupled" is used herein to encompass any direct or indirect electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.

Fig. 1A shows a top view of an Antenna Structure (Antenna Structure)100 according to an embodiment of the invention. Fig. 1B is a perspective view of the antenna structure 100 according to an embodiment of the invention. Please refer to fig. 1A and fig. 1B together. The antenna structure 100 can be applied to a Communication Device (Communication Device), for example: a Wireless Access Point (Wireless Access Point). As shown in fig. 1A and 1B, the antenna structure 100 includes: a Ground Plane (105), a Dielectric Substrate (Dielectric Substrate)110, a first radiating portion (radiating Element)120, a second radiating portion 130, a third radiating portion 140, a fourth radiating portion 150, a first Matching Branch (Matching Branch)170, and a second Matching Branch 180, wherein the Ground Plane 105, the first radiating portion 120, the second radiating portion 130, the third radiating portion 140, the fourth radiating portion 150, the first Matching Branch 170, and the second Matching Branch 180 are made of metal materials, for example: copper, silver, aluminum, iron, or alloys thereof.

The dielectric substrate 110 may be an FR4 (film resistor 4) substrate, a Printed Circuit Board (PCB), or a Flexible Circuit Board (FCB). The dielectric substrate 110 has a first surface E1 and a second surface E2 opposite to each other, wherein the first radiation portion 120, the second radiation portion 130, the third radiation portion 140, the fourth radiation portion 150, the first matching branch 170, and the second matching branch 180 are all disposed on the first surface E1 of the dielectric substrate 110, and the second surface E2 of the dielectric substrate 110 faces and is adjacent to the ground plane 105. 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., 10mm or less), and may also include a case where two corresponding elements are in direct contact with each other (i.e., the distance is shortened to 0 mm). In some embodiments, the dielectric substrate 110 and the ground plane 105 are completely separated and substantially mutually isolatedParallel to the second surface E2 of the dielectric substrate 110 and the ground plane 105 with a spacing distance D therebetween_G。

The first radiating portion 120 is coupled to a Signal Source (Signal Source) 199. For example, the signal source 199 may be a Radio Frequency (RF) module capable of generating a transmission signal or processing a reception signal to excite the antenna structure 100. The first radiation portion 120 may substantially present a square shape. In detail, the first radiation portion 120 has a first edge 121, a second edge 122, a third edge 123, and a fourth edge 124, wherein the first edge 121 and the third edge 123 are opposite to each other, and the second edge 122 and the fourth edge 124 are opposite to each other. The first edge 121, the second edge 122, the third edge 123, and the fourth edge 124 may have substantially the same length.

The second radiation portion 130 may substantially present a square shape. In detail, the second radiation portion 130 has a first edge 131, a second edge 132, a third edge 133, and a fourth edge 134, wherein the first edge 131 and the third edge 133 are opposite to each other, and the second edge 132 and the fourth edge 134 are opposite to each other. The first edge 131, the second edge 132, the third edge 133, and the fourth edge 134 may have substantially the same length.

The third radiation part 140 is coupled between the first radiation part 120 and the second radiation part 130. The third radiating portion 140 may substantially exhibit a rectangular shape. In detail, the third radiating portion 140 has a first edge 141, a second edge 142, a third edge 143, and a fourth edge 144, wherein the first edge 141 and the third edge 143 are opposite to each other, and the second edge 142 and the fourth edge 144 are opposite to each other. The lengths of the second and

fourth edges

142 and 144 may be greater than the lengths of the first and

third edges

141 and 143. The fourth edge 144 of the third radiation part 140 may also extend in the direction of the first radiation part 120 and the second radiation part 130 to connect the first radiation part 120 and the second radiation part 130. The third radiation portion 140 has a first Notch (Notch)161 and a second Notch 162, wherein the first Notch 161 is located at the second edge 142 of the third radiation portion 140, and the second Notch 162 is located at the fourth edge 144 of the third radiation portion 140.

The fourth radiation part 150 is coupled between the first radiation part 120 and the second radiation part 130. The fourth radiation portion 150 may substantially present a rectangle shape. In detail, the fourth radiation portion 150 has a first edge 151, a second edge 152, a third edge 153, and a fourth edge 154, wherein the first edge 151 and the third edge 153 are opposite to each other, and the second edge 152 and the fourth edge 154 are opposite to each other. The lengths of the second and

fourth edges

152 and 154 may be greater than the lengths of the first and

third edges

151 and 153. The second edge 152 of the fourth radiation portion 150 may also extend toward the first radiation portion 120 and the second radiation portion 130 to connect the first radiation portion 120 and the second radiation portion 130. The fourth radiation portion 150 has a third gap 163 and a fourth gap 164, wherein the third gap 163 is located at the second edge 152 of the fourth radiation portion 150, and the fourth gap 164 is located at the fourth edge 154 of the fourth radiation portion 150.

In addition, a fifth gap 165 is formed between the first radiation portion 120 and the third radiation portion 140, a sixth gap 166 is formed between the first radiation portion 120 and the fourth radiation portion 150, a seventh gap 167 is formed between the second radiation portion 130 and the third radiation portion 140, and an eighth gap 168 is formed between the second radiation portion 130 and the fourth radiation portion 150. In detail, the fifth notch 165 is located between the second edge 122 of the first radiation part 120 and the fourth edge 144 of the third radiation part 140, the sixth notch 166 is located between the fourth edge 124 of the first radiation part 120 and the second edge 152 of the fourth radiation part 150, the seventh notch 167 is located between the second edge 132 of the second radiation part 130 and the fourth edge 144 of the third radiation part 140, and the eighth notch 168 is located between the fourth edge 134 of the second radiation part 130 and the second edge 152 of the fourth radiation part 150. In some embodiments, the first notch 161, the second notch 162, the third notch 163, the fourth notch 164, the fifth notch 165, the sixth notch 166, the seventh notch 167, and the eighth notch 168 each have a substantially straight bar shape, wherein each notch can be regarded as a single-pole Slot (Monopole Slot) and has an open end and a closed end. The addition of the aforementioned eight notches can fine-tune the current distribution on the antenna structure 100, thereby improving the directivity of the antenna structure 100.

In summary, the second edge 132 of the second radiation portion 130 is coupled to the second edge 122 of the first radiation portion 120 through the third radiation portion 140, and the fourth edge 134 of the second radiation portion 130 is coupled to the fourth edge 124 of the first radiation portion 120 through the fourth radiation portion 150, so that the first radiation portion 120, the second radiation portion 130, the third radiation portion 140, and the fourth radiation portion 150 together form a Loop Structure (Loop Structure), wherein a hollow portion 195 of the Loop Structure may substantially assume a rectangular shape and is completely surrounded by the third edge 123 of the first radiation portion 120, the first edge 131 of the second radiation portion 130, the fourth edge 144 of the third radiation portion 140, and the second edge 152 of the fourth radiation portion 150.

In some embodiments, a first corner cut-out region 191 is formed adjacent to the second edge 122 of the first radiator 120 and the first edge 141 of the third radiator 140, a second corner cut-out region 192 is formed adjacent to the fourth edge 124 of the first radiator 120 and the first edge 151 of the fourth radiator 150, a third corner cut-out region 193 is formed adjacent to the fourth edge 134 of the second radiator 130 and the third edge 153 of the fourth radiator 150, and a fourth corner notch region 194 is formed adjacent to the second edge 132 of the second radiation part 130 and the third edge 143 of the third radiation part 140, wherein the first corner cut-off region 191, the second corner cut-off region 192, the third corner cut-off region 193, and the fourth corner cut-off region 194 each substantially represent a rectangle, and the areas of the first and second corner notched

regions

191 and 192 may be greater than the areas of the third and fourth corner notched

regions

193 and 194.

The first matching leg 170 may generally take the form of a relatively long straight bar. The signal source 199 may be coupled to a first Connection Point (Connection Point) CP1 on the first edge 121 of the first radiation portion 120 via the first matching branch 170. The first matching branch 170 may have a first end 171 and a second end 172, wherein the first end 171 of the first matching branch 170 is coupled to the first connection point CP1, and the second end 172 of the first matching branch 170 is coupled to the signal source 199. The second matching leg 180 may be substantially in the shape of a relatively short straight bar. The second matching branch 180 may have a first end 181 and a second end 182, wherein the first end 181 of the second matching branch 180 is coupled to a second connection point CP2 on the first edge 121 of the first radiating portion 120, and the second end 182 of the second matching branch 180 is an open end. It should be noted that the first matching leg 170 and the second matching leg 180 are substantially parallel to each other, and the second connection point CP2 is different from the first connection point CP 1.

According to practical measurement results, the antenna structure 100 may cover a first frequency band and a second frequency band, wherein the first frequency band may be between about 2400MHz and 2500MHz, and the second frequency band may be between about 5150MHz and 5850 MHz. Thus, the antenna structure 100 can support at least 2.4GHz/5GHz broadband operation for Bluetooth and WLAN (Wireless Local Area network). It should be noted that the above frequency ranges can also be adjusted according to different requirements. In other embodiments, the antenna structure 100 may cover a gps (global Positioning system) frequency band or an lte (long Term evolution) frequency band, but is not limited thereto.

In terms of antenna principle, the first frequency band is generated by the first radiation portion 120, the second radiation portion 130, the third radiation portion 140, and the fourth radiation portion 150, and the second frequency band is generated by the first radiation portion 120 and the second radiation portion 130. In detail, when the antenna structure 100 operates in the aforementioned first frequency band, the Surface currents (Surface currents) on the first radiation portion 120, the second radiation portion 130, the third radiation portion 140, and the fourth radiation portion 150 can all flow to a first direction (for example, the + Y-axis direction); when the antenna structure 100 operates in the second frequency band, the surface currents on the first radiation portion 120 and the second radiation portion 130 can flow in a second direction (e.g., -Y-axis direction) opposite to the first direction. Therefore, the design of the antenna structure 100 helps to concentrate the surface current thereon, so that the directivity of the Radiation Pattern (Radiation Pattern) thereof can be improved.

Fig. 2A shows a radiation pattern of the antenna structure 100 in the first frequency band according to an embodiment of the invention. Fig. 2B shows a radiation pattern of the antenna structure 100 in the second frequency band according to an embodiment of the invention. From the measurement results shown in fig. 2A and 2B, it can be seen that the Main Beam (Main Beam) of the radiation pattern of the antenna structure 100 in the first frequency band or the second frequency band is directed in the same direction (e.g., + Z-axis direction) and has a sufficient gain value (e.g., at least 7dBi), which can satisfy the practical application requirement of the general mobile communication device.

In some embodiments, the antenna structure 100 has a component size as described below, which is measured-Kilogram-second (MKS) System. It should be noted that the following dimensional ranges are calculated from the results of multiple experiments, and are helpful for optimizing the operating Bandwidth (Operation Bandwidth) and Impedance Matching (Impedance Matching) of the antenna structure 100.

First distance D₁May be interposed between the first edge 121 of the first radiation part 120 and the third edge 133 of the second radiation part 130, or the first distance D₁May be interposed between the second edge 142 of the third radiation part 140 and the fourth edge 154 of the fourth radiation part 150, wherein the first distance D₁The calculation can be made according to equation (1):

wherein "D₁"represents a first distance D₁"c" represents the speed of light, "f₁"represents the center frequency of the aforementioned first frequency band" ε_e"represents an equivalent dielectric constant between about 1 and 1.3," k "represents a first compensation constant between about 0.1 and 0.5, and" h "represents the distance between the first surface E1 and the ground plane 105.

Second distance D₂May be interposed between the first edge 121 and the third edge 123 of the first radiation part 120, or the second distance D₂May be interposed between the first edge 131 and the third edge 133 of the second radiation part 130. In addition, the second distance D₂May be interposed between the second edge 122 and the fourth edge 124 of the first radiating portion 120, or the second distance D₂May be interposed between the second edge 132 and the fourth edge 134 of the second radiating part 130, wherein the second distance D₂The calculation can be made according to equation (2):

wherein "D₂"represents a second distance D₂And f is₂"represents the center frequency of the aforementioned second frequency band. For example, the center frequency f of the first frequency band₁May be equal to the average of 2400MHz and 2500MHz (i.e., 2450MHz), while the center frequency f of the aforementioned second frequency band₂May be equal to the average of 5150MHz and 5850MHz (i.e., 5500 MHz).

Length M of first matching branch 170₁And length M of second matching leg 180₂The calculation can be made according to equations (3) and (4):

wherein "M₁"represents the length M of the first matching branch 170₁，“M₂"represents the length M of the second matching leg 180₂And "m" represents a second compensation constant between about 1 and 1.5.

Third distance D₃May be interposed between the first and

third edges

141 and 143 of the third radiation part 140, or the third distance D₃May be interposed between the first edge 151 and the third edge 153 of the fourth radiation part 150, wherein the third distance D₃The calculation can be made according to equation (5):

wherein "D₃"represents a third distance D₃。

A fourth distance D₄May be interposed between the second notch 162 and the first edge of the first radiation portion 120Between the edges 121, or a fourth distance D₄May be interposed between the third gap 163 and the first edge 121 of the first radiation part 120, wherein the fourth distance D₄The calculation can be made according to equation (6):

wherein "D₄"represents a fourth distance D₄。

A fifth distance D₅May be interposed between the first edge 121 of the first radiation part 120 and the first edge 131 of the second radiation part 130, wherein the fifth distance D₅May be substantially equal to the third distance D₃。

A gap length S of each of the first, second, third, fourth, fifth, sixth, seventh, and

eighth gaps

161, 162, 163, 164, 165, 166, 167, 168_L(i.e., the distance from the open end to the closed end of each notch) can be calculated according to equation (7):

wherein "S_L"represents the gap length S_L。

A notch width S of each of the first notch 161, the second notch 162, the third notch 163, the fourth notch 164, the fifth notch 165, the sixth notch 166, the seventh notch 167, and the eighth notch 168_wMay be less than or equal to 1 mm. The second surface E2 of the dielectric substrate 110 is spaced from the ground plane 105 by a distance D_GMay be less than or equal to 6 mm.

Fig. 3 is a top view of an antenna structure 300 according to another embodiment of the invention. Fig. 3 is similar to fig. 1A. In the embodiment of fig. 3, the antenna structure 300 does not include the first matching branch 170 and the second matching branch 180, wherein the signal source 199 is directly coupled to the first connection point CP 1. With this design, the overall size of the antenna structure 300 can be further reduced. The remaining features of the antenna structure 300 of fig. 3 are similar to those of the antenna structure 100 of fig. 1A and 1B, so that similar operation effects can be achieved in both embodiments.

The invention provides a novel antenna structure, which has the same maximum gain direction of the radiation field pattern no matter the antenna structure operates in high and low frequency bands, thereby effectively enhancing the directivity of the antenna. Compared with the conventional design, the antenna structure of the present invention has at least the advantages of high gain, low loss, light and thin structure, low manufacturing cost, etc., so that the antenna structure is suitable for various communication devices.

It is noted that the sizes, shapes and frequency ranges of the above-mentioned components are not limitations of the present invention. The antenna designer can adjust these settings according to different needs. The antenna structure of the present invention is not limited to the states illustrated in fig. 1 to 3. The present invention may include only any one or more features of any one or more of the embodiments of fig. 1-3. In other words, not all illustrated features may be implemented in the antenna structure of the present invention at the same time.

Ordinal numbers such as "first," "second," "third," etc., in the specification and claims are not to be given a sequential order, but are merely used to identify two different elements having the same name.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. An antenna structure, comprising:

a ground plane;

a dielectric substrate having a first surface and a second surface, wherein the second surface of the dielectric substrate is adjacent to the ground plane;

a first radiation part, which is coupled to a signal source;

a second radiation part;

a third radiation part coupled between the first radiation part and the second radiation part, wherein the third radiation part has a first gap and a second gap; and

a fourth radiation part coupled between the first radiation part and the second radiation part, wherein the fourth radiation part has a third gap and a fourth gap;

wherein the first radiation part, the second radiation part, the third radiation part and the fourth radiation part are all arranged on the first surface of the dielectric substrate;

wherein the first radiation part, the second radiation part, the third radiation part and the fourth radiation part form a ring structure together;

wherein a fifth gap is formed between the first radiation part and the third radiation part, a sixth gap is formed between the first radiation part and the fourth radiation part, a seventh gap is formed between the second radiation part and the third radiation part, and an eighth gap is formed between the second radiation part and the fourth radiation part.

2. The antenna structure of claim 1, wherein the first radiating portion and the second radiating portion each generally exhibit a square shape.

3. The antenna structure of claim 1, wherein the third radiating portion and the fourth radiating portion each substantially exhibit a rectangular shape.

4. The antenna structure of claim 1, wherein the first notch, the second notch, the third notch, the fourth notch, the fifth notch, the sixth notch, the seventh notch, and the eighth notch each substantially present a straight strip shape.

5. The antenna structure of claim 1, wherein each of the first radiating portion, the second radiating portion, the third radiating portion, and the fourth radiating portion has a first edge and a third edge opposite to each other, and a second edge and a fourth edge opposite to each other.

6. The antenna structure of claim 5, further comprising:

a first matching branch, wherein the signal source is coupled to a first connection point on the first edge of the first radiation portion via the first matching branch; and

a second matching branch coupled to a second connection point on the first edge of the first radiating portion;

wherein the second connection point is different from the first connection point.

7. The antenna structure of claim 5, wherein the second edge of the second radiating portion is coupled to the second edge of the first radiating portion via the third radiating portion, and the fourth edge of the second radiating portion is coupled to the fourth edge of the first radiating portion via the fourth radiating portion.

8. The antenna structure of claim 5, wherein the first notch is located at the second edge of the third radiating portion, the second notch is located at the fourth edge of the third radiating portion, the third notch is located at the second edge of the fourth radiating portion, and the fourth notch is located at the fourth edge of the fourth radiating portion.

9. The antenna structure of claim 5, wherein the fifth notch is located between the second edge of the first radiating portion and the fourth edge of the third radiating portion, the sixth notch is located between the fourth edge of the first radiating portion and the second edge of the fourth radiating portion, the seventh notch is located between the second edge of the second radiating portion and the fourth edge of the third radiating portion, and the eighth notch is located between the fourth edge of the second radiating portion and the second edge of the fourth radiating portion.

10. The antenna structure of claim 6 wherein the antenna structure covers a first frequency band between 2400MHz and 2500MHz and a second frequency band between 5150MHz and 5850 MHz.

11. The antenna structure according to claim 10, wherein the first frequency band is generated by the common excitation of the first radiation portion, the second radiation portion, the third radiation portion, and the fourth radiation portion, and the second frequency band is generated by the common excitation of the first radiation portion and the second radiation portion.

12. The antenna structure of claim 10, wherein a first distance is between the first edge of the first radiating section and the third edge of the second radiating section, or between the second edge of the third radiating section and the fourth edge of the fourth radiating section, and the first distance is calculated according to the following equation:

wherein "D₁"represents the first distance," c "represents the speed of light," f₁"represents the center frequency of the first frequency band,". epsilon._e"represents an equivalent dielectric constant between 1 and 1.3," k "represents a first compensation constant between 0.1 and 0.5, and" h "represents a spacing between the first surface and the ground plane.

13. The antenna structure of claim 10, wherein a second distance is between the first edge and the third edge of the first radiating section or between the first edge and the third edge of the second radiating section, and the second distance is calculated according to the following equation:

wherein "D₂"represents the second distance," c "represents the speed of light," f₂"represents the center frequency of the second frequency band,". epsilon._e"represents an equivalent dielectric constant between 1 and 1.3," k "represents a first compensation constant between 0.1 and 0.5, and" h "represents a spacing between the first surface and the ground plane.

14. The antenna structure of claim 10 wherein the length of the first matching branch is calculated according to the following equation:

wherein "M₁"represents the length of the first matching branch," c "represents the speed of light," f₁"represents the center frequency of the first frequency band,". epsilon._e"represents an equivalent dielectric constant between 1 and 1.3, and" m "represents a second compensation constant between 1 and 1.5.

15. The antenna structure of claim 10 wherein the length of the second matching branch is calculated according to the following equation:

wherein "M₂"represents the length of the second matching branch," c "represents the speed of light," f₂"represents the center frequency of the second frequency band,". epsilon._e"represents an equivalent dielectric constant between 1 and 1.3, and" m "represents a second compensation constant between 1 and 1.5.

16. The antenna structure of claim 10, wherein a third distance is between the first edge and the third edge of the third radiating section, or between the first edge and the third edge of the fourth radiating section, and the third distance is calculated according to the following equation:

wherein "D₃"represents the third distance," c "represents the speed of light," f₂"represents the center frequency of the second frequency band,". epsilon._e"represents an equivalent dielectric constant between 1 and 1.3, and" m "represents a second compensation constant between 1 and 1.5.

17. The antenna structure of claim 10, wherein a fourth distance is between the second notch and the first edge of the first radiating portion, or between the third notch and the first edge of the first radiating portion, and the fourth distance is calculated according to the following equation:

wherein "D₄"represents the fourth distance," c "represents the speed of light," f₁"represents the center frequency of the first frequency band,". epsilon._e"represents an equivalent dielectric constant between 1 and 1.3," k "represents a first compensation constant between 0.1 and 0.5, and" h "represents a spacing between the first surface and the ground plane.

18. The antenna structure of claim 16, wherein a fifth distance is between the first edge of the first radiating portion and the first edge of the second radiating portion, and the fifth distance is substantially equal to the third distance.

19. The antenna structure of claim 10, wherein a gap length of each of the first gap, the second gap, the third gap, the fourth gap, the fifth gap, the sixth gap, the seventh gap, and the eighth gap is calculated according to the following equation:

wherein "S_L"represents the gap length," c "represents the speed of light," f₂"represents the center frequency of the second frequency band, and" ε_e"represents an equivalent dielectric constant of between 1 and 1.3.

20. The antenna structure of claim 1, wherein a notch width of each of the first notch, the second notch, the third notch, the fourth notch, the fifth notch, the sixth notch, the seventh notch, and the eighth notch is less than or equal to 1 mm.