Dual feed antenna structure

Abstract

This invention provides a dual-feed antenna structure comprising an antenna body, a first feed point, a second feed point, and a grounding element. The antenna body includes a first arm, a second arm, and a connector. The first arm is disposed adjacent to the second arm, and the connector connects the first arm and the second arm. The first feed point is disposed on the first arm. The second feed point is disposed on the second arm. The grounding element is disposed between the first feed point and the second feed point, and the distance between the first feed point and the grounding element is less than the distance between the second feed point and the grounding element.

Description

Technical Field

[0001] This invention relates to an antenna structure, and more specifically, to a dual-feed antenna structure for generating complementary radiation patterns. Prior Technology

[0002] With the development of technology and the improvement of living standards, 3C products are widely used in daily life, and headphones are one of the most common 3C products. People often use headphones in public places to avoid disturbing others. Headphones include wired headphones and wireless headphones. Due to the advantages of wireless headphones, such as high convenience, lightweight practicality, and freedom from the hassle of wires, wired headphones have gradually been replaced by wireless headphones.

[0003] Generally, headphones contain an antenna that radiates a pattern to receive external signals (such as audio from a mobile phone). Common headphones typically have only one antenna, meaning they generate only one radiation pattern. Because the size and design of the antenna vary depending on the internal space of the headphones, the shape and coverage of the generated radiation pattern differ. If the radiation pattern generated by the headphones cannot cover the distance the signal source can transmit over, dead zones will occur, causing signal interruption and affecting the user experience. Therefore, current technology has developed to install two antennas in a single headphone, each generating a different radiation pattern to reduce dead zones. However, installing two antennas in a single headphone not only increases its size and material cost but also reduces portability. Furthermore, with the miniaturization of electronic products, larger headphones are increasingly unsuitable for market demands, and due to the limited internal space of headphones, the antenna layout still cannot fully account for the radiation pattern, thus reducing reception quality. Summary of the Invention

[0004] In view of this, the present invention provides a dual-feed antenna structure to solve the problems of the prior art.

[0005] In one specific embodiment, the dual-feed antenna structure of the present invention includes an antenna body, a first feed point, a second feed point, and a grounding element. The antenna body includes a first arm, a second arm, and a connector. The first arm is disposed adjacent to the second arm, and the connector connects the first arm and the second arm. The first feed point is disposed on the first arm. The second feed point is disposed on the second arm. The grounding element is disposed between the first feed point and the second feed point, and the distance between the first feed point and the grounding element is less than the distance between the second feed point and the grounding element.

[0006] The antenna body receives signals through a first feed point to generate a first current and a first radiation pattern, and receives signals through a second feed point to generate a second current and a second radiation pattern. The first current flows from the first arm to the second arm, and the second current flows from the second arm to the first arm, with the first and second currents alternating.

[0007] The directions of the first current in the region of maximum current density and the direction of the second current in the region of maximum current density are different axial directions.

[0008] Among them, the region with the highest current density of the first current is located on the connector.

[0009] The region with the highest current density for the second current is located on the second arm.

[0010] The first arm is larger than the second arm.

[0011] The first arm and the second arm are arranged in parallel.

[0012] The directions of the first current in the region of maximum current density and the direction of the second current in the region of maximum current density are perpendicular to each other.

[0013] Among them, the envelope correlation coefficient (ECC) between the first radiation pattern and the second radiation pattern is less than 0.3.

[0014] Among them, the first radiation field type and the second radiation field type are complementary radiation field types.

[0015] The first feed point is located at the end of the first arm away from the connector, and the second feed point is located at the end of the second arm away from the connector.

[0016] The first feed point is located at the end of the first arm near the grounding element.

[0017] The antenna body is C-shaped.

[0018] The grounding element does not contact the antenna body.

[0019] In summary, the dual-feed antenna structure of this invention achieves a dual-antenna effect by using a single antenna architecture and employing an asymmetrical structure between the antenna body and the grounding element, combined with excitation at dual feed points. This reduces space design requirements and material costs. Furthermore, the dual-feed antenna structure of this invention generates currents at different angles and two complementary radiation patterns through alternating excitation at the dual feed points, thereby reducing reception dead zones and improving reception quality. Simple Explanation of the Diagram

[0020]

[0021] Figure 1 is a schematic diagram illustrating a dual-feed antenna structure according to a specific embodiment of the present invention.

[0022] Figure 2 illustrates the current distribution of a dual-feed antenna structure according to a specific embodiment of the present invention when the first feed point is excited.

[0023] Figure 3 illustrates the current distribution of a dual-feed antenna structure according to a specific embodiment of the present invention when the second feed point is excited.

[0024] Figure 4 is a field pattern distribution diagram of a first radiation field pattern and a second radiation field pattern on a plane according to a specific embodiment of the present invention.

[0025] Figure 5 is a field pattern distribution diagram of the first radiation field pattern and the second radiation field pattern according to a specific embodiment of the present invention on another plane.

[0026] Figure 6 is a field pattern distribution diagram of the first radiation field pattern and the second radiation field pattern according to a specific embodiment of the present invention on another plane.

[0027] Figure 7 is a functional block diagram illustrating the application of a dual-feed antenna structure according to a specific embodiment of the present invention to an antenna control system.

[0028] Figure 8 is a flowchart illustrating the steps of controlling a dual-feed antenna structure according to a specific embodiment of the present invention. Implementation

[0029] To make the advantages, spirit, and features of the present invention more easily and clearly understood, detailed descriptions and discussions will follow with reference to the accompanying drawings. It is important to note that these embodiments are merely representative examples of the present invention, and the specific methods, apparatus, conditions, materials, etc., exemplified are not intended to limit the present invention or the corresponding embodiments.

[0030] Please refer to Figure 1. Figure 1 is a schematic diagram illustrating the structure of a dual-feed antenna structure 1 according to a specific embodiment of the present invention. As shown in Figure 1, in this specific embodiment, the dual-feed antenna structure 1 includes an antenna body 11, two feed points, and a grounding element 13. The two feed points are disposed on the antenna body 11, and the grounding element 13 is disposed between the two feed points. In practice, the dual-feed antenna structure 1 of the present invention can be applied to Bluetooth headphones, but is not limited thereto; the dual-feed antenna structure 1 can also be applied to other wireless signal transceivers.

[0031] In this specific embodiment, the antenna body 11 includes a first arm 111A, a second arm 111B, and a connector 112. The second arm 111B is disposed adjacent to the first arm 111A, and the connector 112 connects the first arm 111A and the second arm 111B. As shown in FIG1, the antenna body 11 can be roughly C-shaped and can be disposed on a circuit board. The first arm 111A and the second arm 111B are roughly elongated and each includes two ends, and the connector 112 is connected to the ends of the first arm 111A and the second arm 111B on the same side. The first arm 111A and the second arm 111B are arranged in parallel, and the connector 112 is perpendicularly connected to the first arm 111A and the second arm 111B respectively. The size (width) of the first arm 111A is larger than the size (width) of the second arm 111B. In practice, the width of the first arm 111A and the width of the second arm 111B can also be the same. It is worth noting that in this specific embodiment, the first arm 111A is L-shaped and the second arm 111B is T-shaped, but in practice, it is not limited to this, and the shapes of the first arm 111A and the second arm 111B can also be determined according to the design. In addition, the first arm 111A, the second arm 111B and the connector 112 can also be integrally formed.

[0032] In this specific embodiment, the dual-feed antenna structure 1 includes a first feed point 12A and a second feed point 12B. The first feed point 12A is disposed on the first arm 111A, and the second feed point 12B is disposed on the second arm 111B. Further, the first feed point 12A is disposed at the end of the first arm 111A away from the connector 112, and the second feed point 12B is disposed at the end of the second arm 111B away from the connector 112. The antenna body 11 can receive signals through the first feed point 12A and the second feed point 12B, and these signals are either excitation signals or guided signals.

[0033] In this specific embodiment, the grounding element 13 is disposed between the first arm 111A and the second arm 111B and between the first feed point 12A and the second feed point 12B. As shown in FIG1, the grounding element 13 is located at the end of the first arm 111A and the second arm 111B away from the connector 112, that is, the grounding element 13, the first feed point 12A, and the second feed point 12B are located on the same side of the antenna body 11. Further, in this specific embodiment, the first feed point 12A is disposed at the end of the first arm 111A near the grounding element 13, the distance between the first feed point 12A and the grounding element 13 is less than the distance between the second feed point 12B and the grounding element 13, and the grounding element 13 does not contact the antenna body 11.

[0034] The dual-feed antenna structure 1 of the present invention is a monopole antenna structure. When the antenna body 11 receives a signal through the first feed point 12A, the second feed point 12B is in an open-circuit state. At this time, the antenna body 11 can be regarded as a first antenna and generates a first current, and the dual-feed antenna structure 1 can generate a first radiation pattern according to the first current. When the antenna body 11 receives a signal through the second feed point 12B, the first feed point 12A is in an open-circuit state. At this time, the antenna body 11 can be regarded as a second antenna and generates a second current, and the dual-feed antenna structure 1 can generate a second radiation pattern according to the second current. The radiation range covered by the first and second radiation patterns can be used to receive external signals.

[0035] Please refer to Figures 1 and 2 together. Figure 2 is a current distribution diagram illustrating the dual-feed antenna structure 1 according to a specific embodiment of the present invention when the first feed point 12A is excited. The triangular arrows on the antenna body 11 and the grounding element 13 in the figure indicate the direction of current flow. As shown in Figures 1 and 2, when the first feed point 12A is excited, the current generated by the antenna body 11 flows from the first arm 111A through the connector 112, and then to the second arm 111B. It is worth noting that the distance between the grounding element 13 and the first feed point 12A is small, that is, the grounding element 13 is closer to the first arm 111A. Therefore, when the antenna body 11 generates the first current, the grounding element 13 and the first arm 111A are greatly affected by the coupling effect, causing the current of the first arm 111A to move towards the connector 112 (moving upward in Figure 2), while the current of the grounding element 13 moves away from the connector 112 (moving downward in Figure 2). That is, the current directions of the grounding element 13 and the first arm 111A are opposite, resulting in electromagnetic coupling between the first arm 111A and the grounding element 13, which in turn causes the region with the maximum current density of the first current to be located on the connector 112 (as shown by the arrow in the figure).

[0036] Please refer to Figures 1 and 3 together. Figure 3 is a current distribution diagram of the dual-feed antenna structure 1 according to a specific embodiment of the present invention when the second feed point 12B is excited. The triangular arrows on the antenna body 11 and the grounding element 13 in the figure indicate the direction of current flow. As shown in Figures 1 and 3, when the second feed point 12B is excited, the current generated by the antenna body 11 flows from the second arm 111B through the connector 112, and then flows to the first arm 111A. Since the distance between the grounding element 13 and the second feed point 12B is greater than the distance between the grounding element 13 and the first feed point 12A, and the distance between the grounding element 13 and the second arm 111B is greater than the distance between the grounding element 13 and the first arm 111A. When the antenna body 11 generates a second current, the grounding element 13 and the second arm 111B are less affected by the coupling effect, resulting in a smaller electromagnetic cancellation between the second arm 111B and the grounding element 13. That is, the current on the second arm 111B is less affected by the grounding element 13. Therefore, the region with the maximum current density of the second current is located on the second arm 111B (as shown by the arrow in the figure).

[0037] As shown in Figure 1, in this specific embodiment, the first arm 111A and the second arm 111B are arranged in parallel, and the connector 112 is perpendicularly connected to the second arm 111B. Therefore, the current direction of the first current in the region of maximum current density and the current direction of the second current in the region of maximum current density are perpendicular to each other. Furthermore, since the current directions of the first current and the second current in the region of maximum current density are different, the shapes and coverage areas of the first radiation pattern and the second radiation pattern generated by the dual-feed antenna structure 1 are also different.

[0038] Please refer to Figures 1, 4, 5, and 6 together. Figure 4 illustrates the field pattern distribution of the first radiation pattern P1 and the second radiation pattern P2 in the XY plane according to a specific embodiment of the present invention. Figure 5 illustrates the field pattern distribution of the first radiation pattern P1 and the second radiation pattern P2 in the YZ plane according to a specific embodiment of the present invention. Figure 6 illustrates the field pattern distribution of the first radiation pattern P1 and the second radiation pattern P2 in the XZ plane according to a specific embodiment of the present invention. The field pattern distribution diagrams in Figures 4 to 6 include the first radiation pattern P1, the second radiation pattern P2, and the total radiation pattern P3 combining the first radiation pattern P1 and the second radiation pattern P2. In this specific embodiment, the first radiation pattern P1 and the second radiation pattern P2 are complementary radiation patterns, and the envelope correlation coefficient (ECC) between the first radiation pattern and the second radiation pattern is less than 0.5, for example, 0.3. As shown in Figure 4, when the dual-feed antenna structure 1 excites the first feed point 12A to generate the first radiation pattern P1, the first radiation pattern P1 includes a first reception dead zone S1 and a second reception dead zone S2. When the dual-feed antenna structure 1 excites the second feed point 12B to generate the second radiation pattern P2, the radiation range of the second radiation pattern P2 can cover the first reception dead zone S1 and the second reception dead zone S2 of the first radiation pattern P1. As shown in Figure 5, when the dual-feed antenna structure 1 excites the second feed point 12B to generate the second radiation pattern P2, the second radiation pattern P2 includes a third reception dead zone S3. When the dual-feed antenna structure 1 excites the first feed point 12A to generate the first radiation pattern P1, the radiation range of the first radiation pattern P1 can cover the third reception dead zone S3 of the second radiation pattern P2. In other words, the first radiation pattern P1 and the second radiation pattern P2 can compensate for each other's reception dead zones to form complementary radiation patterns. Therefore, the dual-feed antenna structure of the present invention achieves the dual-antenna effect with a single antenna architecture and through the excitation of dual feed points, generating two complementary radiation patterns to reduce reception dead zones, thereby improving reception quality and reducing space requirements and costs.

[0039] The dual-feed antenna structure of the present invention can be in other forms besides the aforementioned specific embodiments. In one specific embodiment, the first arm and the second arm of the antenna body can be arranged adjacent to each other at an angle (i.e., not parallel), and the second arm is not parallel to the connector. When the dual-feed antenna structure excites the first feed point and the second feed point respectively, the current direction of the first current in the region of maximum current density and the current direction of the second current in the region of maximum current density are different axial directions (also different angular directions), thereby generating a first radiation field pattern and a second radiation field pattern with different shapes, different radiation coverage, and are complementary.

[0040] Since the dual-feed antenna structure generates two currents in different directions by using the asymmetrical structure between the antenna body and the grounding element and the excitation of two feed points, the dual-feed antenna structure of the present invention can generate complementary first and second radiation patterns in any signal frequency band, and the first and second radiation patterns can be used to receive external signals in any frequency band.

[0041] Please refer to Figures 1 and 7 together. Figure 7 is a functional block diagram illustrating the application of a dual-feed antenna structure 1 to an antenna control system S according to a specific embodiment of the present invention. As shown in Figure 7, the antenna control system S includes the dual-feed antenna structure 1, a control module 2, and a switching switch 3. The control module 2 is electrically connected to the switching switch 3, and the switching switch 3 is electrically connected to the dual-feed antenna structure 1. The control module 2 is used to emit an excitation signal or a conduction signal. The switching switch 3 is used to selectively activate the first feed point 12A and the second feed point 12B.

[0042] In practice, the antenna control system S can be applied to Bluetooth headsets or other signal transceivers. The control module 2 may include a signal generator 21 and a controller 22. The signal generator 21 generates an excitation signal and / or a conduction signal, and the controller 22 controls the signal generator 21 to emit the signal. Furthermore, the controller 22 can also control the switching of the switch 3. When the controller 22 controls the switch 3 to switch to the first feed point 12A, the control module 2 and the first feed point 12A are in a conducting state. At this time, the controller 22 can control and transmit the excitation signal to the first feed point 12A, so that the dual-feed antenna structure 1 generates a first current and a first radiation pattern for transmitting and receiving signals. When the controller 22 controls the switch 3 to switch to the second feed point 12B, the control module 2 and the second feed point 12B are in a conducting state. At this time, the controller 22 can control and transmit the excitation signal to the second feed point 12B, so that the dual-feed antenna structure 1 generates a second current and a second radiation pattern for transmitting and receiving signals. Therefore, the antenna control system S can selectively and alternately generate the first current and the second current by controlling the switching switch, thereby generating a first radiation pattern and a second radiation pattern with different signal coverage and complementarity.

[0043] Please refer to Figure 8. Figure 8 is a flowchart illustrating the steps of controlling the dual-feed antenna structure 1 according to a specific embodiment of the present invention. The steps of Figure 8 can be achieved through the antenna control system S of Figure 7. As shown in Figure 8, the process of the antenna control system S controlling the dual-feed antenna structure 1 includes the following steps: Step S1: Control the dual-feed antenna structure 1 to receive external signals using the first antenna; Step S2: Detect and determine whether the signal strength of the first antenna is greater than the signal strength threshold. If the determination result is no, then execute step S3: Switch and control the dual-feed antenna structure 1 to receive external signals using the second antenna; Step S4: Detect and determine whether the signal strength of the second antenna is greater than the signal strength threshold. If the determination result is no, then execute step S5: Switch to the antenna with better signal strength to receive external signals.

[0044] In step S1, the control module 2 of the antenna control system S can first control the switching switch 3 to switch to the first feed point and transmit the excitation signal so that the dual-feed antenna structure 1 generates the first current and the first radiation field pattern to receive external signals.

[0045] In step S2, the control module 2 may include a signal strength measurement unit (not shown) to measure the received signal strength (RSSI) of the antenna. Further, the control module 2 may pre-store a signal strength threshold, which can be determined according to design or requirements. After the first antenna of the dual-feed antenna structure 1 generates the first radiation pattern, the control module 2 measures and determines whether the signal strength of the first antenna is greater than the signal strength threshold.

[0046] When the judgment result of control module 2 is yes, it indicates that the first antenna is receiving signals well. At this time, control module 2 does not control switch 3, and the dual-feed antenna structure 1 continues to receive external signals through the first antenna. When the judgment result of control module 2 is no, it indicates that the first antenna is receiving signals poorly or is in a reception dead zone, and then step S3 is executed.

[0047] In step S3, the control module 2 controls the switching switch 3 to switch to the second feed point and transmits an excitation signal, so that the dual-feed antenna structure 1 switches from the first antenna to the second antenna and generates a second current and a second radiation pattern to receive external signals.

[0048] In step S4, after the second antenna of the dual-feed antenna structure 1 generates the second radiation pattern, the control module 2 measures and determines again whether the signal strength of the second antenna is greater than the signal strength threshold. Similarly, if the determination result of the control module 2 is yes, it indicates that the second antenna is receiving signals well. At this time, the control module 2 does not control the switching switch 3, and the dual-feed antenna structure 1 continues to receive external signals with the second antenna. If the determination result of the control module 2 is no, it indicates that the second antenna is receiving signals poorly, and then step S5 is executed.

[0049] In step S5, control module 2 selects the preferred antenna based on the signal strength of the first and second antennas measured by the signal strength measurement unit. When the signal strength of the first antenna is greater than that of the second antenna, control module 2 controls switch 3 again to switch to the first feed point, so that the dual-feed antenna structure 1 receives external signals using the first antenna. When the signal strength of the second antenna is greater than that of the first antenna, control module 2 does not control switch 3, and the dual-feed antenna structure 1 continues to receive external signals using the second antenna. Furthermore, control module 2 can pre-store a detection time length. After control module 2 selects the preferred antenna, it can execute step S2 again based on the detection time length to detect and determine the signal strength of the currently selected antenna.

[0050] It is worth noting that in the specific embodiment of Figure 8, the first antenna of the dual-feed antenna structure is first controlled as the preset antenna to receive external signals. However, in practice, it is not limited to this. The antenna control system can also use the second antenna of the dual-feed antenna structure as the preset antenna, or randomly select one of the antennas as the preset antenna.

[0051] In summary, the dual-feed antenna structure of this invention achieves a dual-antenna effect by using a single antenna architecture and employing an asymmetrical structure between the antenna body and the grounding element, combined with excitation at dual feed points. This reduces space design requirements and material costs. Furthermore, the dual-feed antenna structure of this invention generates currents at different angles and two complementary radiation patterns through alternating excitation at the dual feed points, thereby reducing reception dead zones and improving reception quality.

[0052] The detailed description of the above embodiments is intended to clearly illustrate the features and spirit of the present invention, and is not intended to limit the invention to the preferred embodiments disclosed above. Rather, the aim is to cover various modifications and equivalent arrangements within the scope of the patent claims made by this invention. Therefore, the scope of the patent claims made by this invention should be interpreted in the broadest possible sense based on the foregoing description, so as to cover all possible modifications and equivalent arrangements.

[0053] 1: Dual-feed antenna structure

[0054] 11: Antenna Body

[0055] 111A: First Arm

[0056] 111B: Second Arm

[0057] 112: Connector

[0058] 12A: First feed point

[0059] 12B: Second Feed Point

[0060] 13: Grounding element

[0061] P1: First radiation field type

[0062] P2: Second radiation field type

[0063] P3: Total Radiation Field Pattern

[0064] S1: First reception dead zone

[0065] S2: Second reception dead zone

[0066] S3: Third reception dead zone

[0067] 2: Control Module

[0068] 21: Signal Generator

[0069] 22: Controller

[0070] 3: Switch

[0071] S: Antenna control system

[0072] S1~S5: Steps

Claims

1. A dual-feed antenna structure, comprising: an antenna body, the antenna body being C-shaped, and including a first arm, a second arm, and a connector, the first arm being adjacent to the second arm, and the connector connecting the first arm and the second arm; a first feed point disposed on the first arm; a second feed point disposed on the second arm; and a grounding element disposed between the first feed point and the second feed point and surrounded by the first arm, the second arm, and the connector of the C-shaped antenna body, the grounding element not contacting the antenna body; wherein, The distance between the first feed point and the grounding element is less than the distance between the second feed point and the grounding element; the antenna body receives signals through the first feed point to generate a first radiation pattern and receives signals through the second feed point to generate a second radiation pattern, the first radiation pattern and the second radiation pattern are complementary radiation patterns located in the same frequency band.

2. The dual-feed antenna structure as described in claim 1, wherein the antenna body receives a signal through the first feed point to generate a first current, the antenna body receives a signal through the second feed point to generate a second current, wherein the first current flows from the first arm to the second arm, the second current flows from the second arm to the first arm, and the first current and the second current alternate.

3. The dual-feed antenna structure as described in claim 2, wherein the current direction of the first current in the region of maximum current density and the current direction of the second current in the region of maximum current density are different axial directions.

4. The dual-feed antenna structure as described in claim 3, wherein the region of maximum current density of the first current is located on the connector.

5. The dual-feed antenna structure as described in claim 3, wherein the region of maximum current density of the second current is located on the second arm.

6. The dual-feed antenna structure as described in claim 1, wherein the size of the first arm is larger than the size of the second arm.

7. The dual-access antenna structure as described in claim 1, wherein the first arm and the second arm are arranged in parallel.

8. The dual-feed antenna structure as described in claim 7, wherein the current direction of the first current in the region of maximum current density and the current direction of the second current in the region of maximum current density are perpendicular to each other.

9. The dual-feed antenna structure as described in claim 1, wherein the envelope correlation coefficient (ECC) between the first radiation pattern and the second radiation pattern is less than 0.

5.

10. The dual-feed antenna structure as described in claim 1, wherein the first feed point is located at the end of the first arm away from the connector, and the second feed point is located at the end of the second arm away from the connector.

11. The dual-feed antenna structure as described in claim 10, wherein the first feed point is located at the end of the first arm near the grounding element.

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