Miniaturized positioning antennas and wearable devices

Abstract

A miniaturized positioning antenna and a wearable device, the miniaturized positioning antenna comprising: a ring radiator, the ring radiator being loaded with an inductor at the position of the maximum current when in operation; a first branch, coupled to the ring radiator, the first branch being used to access a first feeding signal at one end away from the ring radiator. The above-mentioned miniaturized positioning antenna is loaded with an inductor at the position of the maximum current on the ring radiator, so that the resonant frequency is reduced. The greater the loaded inductance value, the lower the frequency, indicating that the effect of miniaturization achieved by loading the inductor is obvious, thereby ensuring that the performance of the antenna will not be reduced while miniaturizing the antenna and improving the positioning accuracy.

Description

Technical Field

[0001] The present application belongs to the field of antenna technology, and in particular relates to a miniaturized positioning antenna and a wearable device. Background Art

[0002] In the field of smart watches or wristbands, positioning accuracy has always been a pain point that people are concerned about. Traditional smart watches or wristbands have linearly polarized positioning antennas, but the signals sent by navigation satellites are right-hand circularly polarized signals after passing through the ionosphere. Therefore, the positioning antennas of smart watches or wristbands cannot receive all the signals from navigation satellites. The signals from navigation satellites are reflected an odd number of times by the ground, tall buildings, trees, etc., and become left-hand circularly polarized signals. The multipath interference generated will seriously affect the positioning effect of the entire device.

[0003] In addition, due to the small size of wearable devices, whether traditional linear polarization antennas or circular polarization antennas are to be integrated into wearable devices, the shape or structure of the antennas have to be changed due to volume limitations, which greatly reduces the performance of the antennas and reduces the positioning accuracy, seriously affecting the positioning effect of the entire device. Summary of the invention

[0004] The purpose of the present application is to provide a miniaturized positioning antenna and a wearable device, aiming to solve the problem that the performance of traditional positioning antennas is reduced and the positioning accuracy is poor due to the limited available space.

[0005] A first aspect of an embodiment of the present application provides a miniaturized positioning antenna, comprising:

[0006] A ring radiator, wherein the ring radiator is loaded with an inductor at a position where the current is maximum during operation;

[0007] The first branch is coupled to the annular radiator, and one end of the first branch away from the annular radiator is used for receiving a first feeding signal.

[0008] The above-mentioned miniaturized positioning antenna is loaded with an inductor at the position of the maximum current on the ring radiator, so that the resonant frequency is reduced. The greater the inductance value, the lower the frequency, which shows that the effect of miniaturization achieved by loading inductors is obvious, so that the antenna can be miniaturized while ensuring that its performance is not reduced and the positioning accuracy is improved.

[0009] In one embodiment, the inductor device is a lumped inductor or a distributed inductor.

[0010] In one embodiment, the annular radiator is a square annular structure, a rounded square annular structure, a rectangular annular structure, a rounded rectangular annular structure, an elliptical annular structure or a circular annular structure, and the equivalent length of the annular radiator corresponds to the working wavelength.

[0011] In one embodiment, a line connecting the first branch and the center of the ring radiator and a line connecting the inductor and the center of the ring radiator are perpendicular to each other.

[0012] In one embodiment, there are two inductors, and the distances between the two inductors and the positions where the first branch and the annular radiator are coupled are equal along the periphery of the annular radiator.

[0013] In one embodiment, the annular radiator is a square annular structure, a rounded square annular structure, a rectangular annular structure or a rounded rectangular annular structure, and the first branch is coupled and connected to the first edge of the annular radiator; there are two inductance devices, which are respectively arranged at the middle position of two edges adjacent to the first edge on the annular radiator.

[0014] In one embodiment, a second branch is further included, which is coupled to the annular radiator and has a preset distance from the first branch. An end of the second branch away from the annular radiator is used for grounding or for connecting a second feed signal. The first feed signal and the second feed signal have a phase difference of 90°.

[0015] In this embodiment, one branch is coupled and fed, and the other branch is also coupled and fed or grounded, thereby exciting two radiation modes of the annular radiator. The two radiation modes have the same amplitude and a phase difference of 90 degrees, that is, the annular radiator generates right-handed circularly polarized radiation, so that the positioning antenna can better receive navigation satellite signals. At the same time, the right-handed circularly polarized radiation generated by the annular radiator can also filter the left-handed circularly polarized navigation satellite signals reflected by high-rise buildings or the ground to reduce multipath interference, thereby effectively improving the positioning accuracy of the positioning antenna of the wearable device.

[0016] In one embodiment, the preset distance is the distance between the first branch and the second branch along the periphery of the annular radiator, which is 0.125 to 0.375 times the working wavelength of the annular radiator;

[0017] When the annular radiator is a square structure, a rounded square structure, a rectangular structure or a rounded rectangular structure, the first branch node and the second branch node are respectively adjacent to two of the annular radiators and are opposite to each other with coupling gaps.

[0018] In one embodiment, there are four inductance devices, and the inductance devices are evenly spaced along the circumference of the annular radiator, and the first branch node and the second branch node are respectively opposite to two adjacent inductance devices.

[0019] In one embodiment, the first branch node and the second branch node are T-shaped or inverted L-shaped.

[0020] A second aspect of an embodiment of the present application provides a wearable device, comprising a circuit board and the miniaturized positioning antenna as described above, wherein an end of a first branch of the miniaturized positioning antenna away from the annular radiator is connected to a radio frequency port of the circuit board.

[0021] The above-mentioned wearable device adopts all the embodiments of the above-mentioned miniaturized positioning antenna, and thus has at least all the beneficial effects of the above-mentioned embodiments, which will not be described one by one here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of a miniaturized positioning antenna provided in Embodiment 1 of the present invention;

[0023] Figure 2 A schematic diagram of current simulation of a miniaturized positioning antenna provided in Embodiment 1 of the present invention;

[0024] Figure 3 for Figure 1 The S-parameter schematic diagram of the miniaturized positioning antenna shown;

[0025] Figure 4 A schematic diagram of the structure of a miniaturized positioning antenna provided in Embodiment 2 of the present invention;

[0026] Figure 5 A schematic diagram of S parameters of a miniaturized positioning antenna provided in the second embodiment of the present invention;

[0027] Figure 6 for Figure 5 A two-dimensional top axis ratio simulation diagram of the miniaturized positioning antenna shown;

[0028] Figure 7 for Figure 5 A schematic diagram of the two-dimensional top right-hand circular polarization gain of the miniaturized positioning antenna shown;

[0029] Figure 8 for Figure 5 The two-dimensional axial ratio simulation diagram of the phi=0° and 90° sections of the miniaturized positioning antenna shown;

[0030] Fig. 9 for Figure 5 Schematic diagram of the right-hand circular polarization gain of the miniaturized positioning antenna shown in FIG. 1 at phi=0° and 90°. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0033] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] See also Figure 1 An embodiment of the present application provides a miniaturized positioning antenna that can be used for a wearable device, including a ring radiator 10 and a first branch 20 .

[0036] The annular radiator 10 operates in a first frequency band, such as 1.575 GHz or 1.176 GHz. Optionally, the main body of the annular radiator 10 is a centrosymmetric structure or an axisymmetric structure, such as a square annular structure, a rounded square annular structure, a rectangular annular structure, a rounded rectangular annular structure, an elliptical annular structure or a circular annular structure, etc. The annular radiator 20 is loaded with an inductor 30 at a position of maximum current when working; the first branch 20 is coupled to the annular radiator 10, and an end of the first branch 20 away from the annular radiator 10 is used to access the first feeding signal.

[0037] The above-mentioned miniaturized positioning antenna is loaded with an inductor device 20 at the position of the maximum current on the ring radiator 10, which is used to extend the effective length of the ring radiator 10 to reduce the size of the positioning antenna and effectively miniaturize the antenna. After the radiator of the same size is loaded with inductance, the resonant frequency is reduced, and the greater the loaded inductance value, the lower the frequency, which shows that the effect of miniaturization achieved by loading inductance is obvious, so that while the antenna can be miniaturized, its performance is not reduced and the positioning accuracy is improved.

[0038] The inductor device 30 is a lumped inductor, i.e., an inductor, or a distributed inductor, i.e., the frame of the ring radiator 10 is arranged with a serpentine curved line to realize the distributed inductor. The range of inductance values ​​can be flexibly selected according to the specific operating frequency band and the limited size of the ring radiator 10. The larger the inductance, the smaller the volume of the ring radiator 10 can be. In some cases where high miniaturization is required, most or all of the sides of the ring radiator 10 can be composed of distributed inductors, i.e., most or all of the sides are serpentine curved lines, or multiple inductors are loaded.

[0039] In one embodiment, the equivalent length of the ring radiator 10 corresponds to the working wavelength. For example, the equivalent length of the ring radiator 10 is substantially equal to the working wavelength, or the equivalent length of the ring radiator 10 is substantially equal to 1 / 4 of the working wavelength, so as to ensure that the antenna resonates at a desired frequency. The equivalent length of the ring radiator 10 can be understood as the circumference of the ring radiator 10 plus the equivalent length of the loaded inductor.

[0040] See also Figure 2 , the larger the arrow-shaped figure on the ring radiator 10, the darker the color, the larger the current value. When the ring radiator 10 is a centrally symmetrical figure, taking a square structure as an example, after the current is coupled from the first branch 20 to the first side of the ring radiator, it is divided into two paths and reaches the maximum after flowing through 1 / 4 of the circumference. There are two locations where the current is the largest, which are the two sides adjacent to the first side. Therefore, the inductor 30 is arranged at these two locations, so that the line between the first branch 20 and the center of the ring radiator 10 and the line between the inductor 30 and the center of the ring radiator 10 are perpendicular to each other.

[0041] From another perspective, it can be understood that when there are two inductors 30, the distances between the two inductors 30 and the positions where the first branch 20 and the annular radiator 10 are coupled are equal along the periphery of the annular radiator 10. For example, the annular radiator 10 is a square annular structure, a rounded square annular structure, a rectangular annular structure, or a rounded rectangular annular structure, and the first branch 20 is coupled to the first side of the annular radiator 10; there are two inductors 30, which are respectively arranged at the middle positions of the two sides adjacent to the first side of the annular radiator 10.

[0042] See also Figure 3 Therefore, it is not difficult to see that when the inductor is loaded at the position of the maximum current, the resonant frequency is reduced, where LL is the equivalent inductance value of the loaded inductor device 30, and there are four S parameter simulation parameter curves of LL=3nH, 5nH, 7nH and no loading. It can be seen that the larger the loaded inductance value, the lower the frequency, which shows that the effect of miniaturization achieved by loading the inductor is obvious, and the specific effect can be well controlled.

[0043] See also Figure 4In one embodiment, the miniaturized positioning antenna further includes a second branch 40, which is coupled to the annular radiator 10 and has a preset distance from the first branch 20. The end of the second branch 40 away from the annular radiator 10 is used for grounding or for accessing a second feed signal, and the first feed signal and the second feed signal differ in phase by 90°. In this embodiment, one branch is used for coupling and feeding, and the other branch is also coupled and fed or grounded, thereby stimulating two radiation modes of the annular radiator 10. The two radiation modes have the same amplitude and a phase difference of 90 degrees, that is, the annular radiator 10 generates right-handed circularly polarized radiation, so that the positioning antenna can better receive navigation satellite signals. At the same time, the right-handed circularly polarized radiation generated by the annular radiator 10 can also filter the left-handed circularly polarized navigation satellite signals reflected by high-rise buildings or the ground to reduce multipath interference, thereby effectively improving the positioning accuracy of the positioning antenna of the wearable device.

[0044] One end of the second branch 40 away from the annular radiator 10 is used for grounding 100 and one end of the second branch 40 away from the annular radiator 10 is used for receiving the second feeding signal. These two implementations have similar performances and can be selected as needed in application.

[0045] In one embodiment, the preset distance is the distance between the first branch 20 and the second branch 40 along the periphery of the annular radiator 10, which is 0.125 to 0.375 times the working wavelength of the annular radiator 10; and when the annular radiator 10 is a square structure, a rounded square structure, a rectangular structure or a rounded rectangular structure, the first branch 20 and the second branch 40 are respectively opposite to the two adjacent sides of the annular radiator 10 with a coupling gap. In the solution provided in the third embodiment, the first branch 20 and the second branch 40 are respectively arranged at the midpoint of the two adjacent sides of the square-shaped annular radiator 1010, and the antenna is better at this time, with a good circular polarization effect.

[0046] In one embodiment, there are four inductors 30, and the annular radiator 10 is a centrally symmetrical figure. Taking a square structure as an example, after the current is coupled from the first branch 20 to the first side of the annular radiator 10, it is divided into two paths and reaches a maximum after flowing through 1 / 4 of the circumference. There are two positions where the current is maximum, which are located on two sides adjacent to the first side, so the inductors 30 are set at these two positions. Similarly, it can be obtained from the second branch 40 coupled to the annular radiator 10 that the other two inductors are set on the first side and the side opposite thereto. The inductors 30 are evenly arranged along the circumferential direction of the annular radiator 10, and the first branch 20 and the second branch 40 are respectively opposite to the two adjacent inductors 30.

[0047] In addition, the branch and the radiator are fed by slot coupling, which makes matching and tuning easier. Specifically, the first branch 20 and / or the second branch 40 include a first coupling section and a second coupling section, the long side of the first coupling section is directly opposite to the edge of the annular radiator 10 and a coupling slot is provided between the two, the first end of the second coupling section is connected to the first coupling section, and the second end extends in a direction away from the first coupling section and serves as an end away from the annular radiator 10. Thus, the main body of the branch constitutes a T-shaped structure or an inverted L-shaped structure, and by adjusting the size of the branch and the spacing of the coupling slots, the coupling degree can be adjusted to achieve matching tuning of the antenna.

[0048] In some embodiments, the plane where the first branch 20 and the plane where the second branch 40 are located are perpendicular to the plane where the annular radiator 10 is located; in other embodiments, the projections of the first branch 20 and the second branch 40 in the direction perpendicular to the plane where the annular radiator 10 is located fall outside the range of the plane, and the angle formed by the plane where the first branch 20 and the plane where the second branch 40 are located and the plane where the annular radiator 10 is located is between ±90°.

[0049] In other embodiments, the branch and the radiator are directly fed, and the first branch 20 and / or the second branch 40 both include a capacitor and a third coupling segment, one end of the capacitor is connected to the ring radiator 10, and the other end is connected to the first end of the third coupling segment, and the second end of the third coupling segment is the end away from the ring radiator 10. In this way, another implementation method of branches and coupling is provided, and capacitors with different capacitances can be selected to adjust the coupling degree to achieve matching tuning of the antenna. It can be understood that the first branch 20 and the second branch 40 can select the same coupling mode or different coupling modes in the above two coupling modes.

[0050] See also Figure 5 It can be seen that compared with the radiator of the same size, the resonant frequency drops significantly after loading the inductor. Moreover, the resonant frequency is readjusted to 1.575GHz by reducing the overall size of the antenna. Check the circular polarization effect. The above miniaturized positioning antenna resonates at 1.575GHz, and the impedance bandwidth (S11<-6dB) can completely cover the GPS-L1 frequency band (1575±2MHz), indicating that the above positioning antenna has good reception of navigation satellite signals.

[0051] from Figure 6 and Figure 8It can be seen that when the above-mentioned positioning antenna operates at the GPS L1 frequency band of 1.575 GHz, the axial ratio of the top of the positioning antenna (phi=0°, theta=0°) is below 2.3 dB. When the above-mentioned positioning antenna operates at the GPS-L1 frequency band of 1.575 GHz and the section is phi=0°, 90°, in the range of θ=-70 to 70°, the axial ratio of the positioning antenna is less than 10 dB, indicating that the axial ratio characteristics of the above-mentioned positioning antenna are good and meet the performance requirements of the positioning antenna.

[0052] from Figure 7 and Fig. 9 It can be seen that when the above-mentioned positioning antenna operates in the GPS-L1 frequency band of 1.575 GHz, the right-hand circular polarization gain of the top of the positioning antenna (phi=0°, theta=0°) is about 1.5 dB. Under the same gain, the circularly polarized antenna receives satellite signals 3 dB better than the traditional linearly polarized antenna, so the positioning effect of the above-mentioned positioning antenna is better than that of the traditional linearly polarized antenna.

[0053] In addition, the present application also provides a wearable device, including a circuit board and a miniaturized positioning antenna as in any of the above embodiments, wherein an end of a first branch 20 of the miniaturized positioning antenna away from the annular radiator 10 is connected to a first RF port of the circuit board.

[0054] Furthermore, one end of the second branch 40 of the miniaturized positioning antenna away from the annular radiator 10 is connected to the second RF port of the circuit board or the ground port of the circuit board.

[0055] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A miniaturized positioning antenna, characterized in that: include: A ring radiator, wherein the ring radiator is loaded with an inductor at a position where the current is maximum during operation; The first branch is coupled to the annular radiator, and one end of the first branch away from the annular radiator is used for receiving a first feeding signal.

2. The miniaturized positioning antenna according to claim 1, characterized in that: The inductor device is a lumped inductor or a distributed inductor.

3. The miniaturized positioning antenna according to claim 1, characterized in that: The annular radiator is a square annular structure, a rounded square annular structure, a rectangular annular structure, a rounded rectangular annular structure, an elliptical annular structure or a circular annular structure, and the equivalent length of the annular radiator corresponds to the working wavelength.

4. The miniaturized positioning antenna according to claim 1, characterized in that: A line connecting the first branch and the center of the annular radiator and a line connecting the inductor and the center of the annular radiator are perpendicular to each other.

5. The miniaturized positioning antenna according to claim 1, characterized in that: There are two inductors, and the distances between the two inductors and the positions where the first branch and the annular radiator are coupled are equal along the periphery of the annular radiator.

6. The miniaturized positioning antenna according to claim 1, 4 or 5, characterized in that: The annular radiator is a square annular structure, a rounded square annular structure, a rectangular annular structure or a rounded rectangular annular structure, and the first branch is coupled and connected to the first side of the annular radiator; there are two inductance devices, which are respectively arranged at the middle position of two sides adjacent to the first side on the annular radiator.

7. The miniaturized positioning antenna according to any one of claims 1 to 4, characterized in that: It also includes a second branch, which is coupled to the annular radiator and has a preset distance from the first branch. The end of the second branch away from the annular radiator is used for grounding or for connecting a second feed signal. The first feed signal and the second feed signal have a phase difference of 90°.

8. The miniaturized positioning antenna according to claim 7, characterized in that: The preset distance is the distance between the first branch and the second branch along the periphery of the annular radiator, which is 0.125 to 0.375 times the working wavelength of the annular radiator; When the annular radiator is a square structure, a rounded square structure, a rectangular structure or a rounded rectangular structure, the first branch node and the second branch node are respectively adjacent to two of the annular radiators and are opposite to each other with coupling gaps.

9. The miniaturized positioning antenna according to claim 7, characterized in that: There are four inductance devices, and the inductance devices are evenly spaced along the circumference of the annular radiator, and the first branch node and the second branch node are respectively opposite to two adjacent inductance devices.

10. The miniaturized positioning antenna according to claim 7, characterized in that: The first branch node and the second branch node are T-shaped or inverted L-shaped.

11. A wearable device, characterized in that: It comprises a circuit board and the miniaturized positioning antenna as claimed in any one of claims 1 to 10, wherein one end of a first branch of the miniaturized positioning antenna away from the annular radiator is connected to a radio frequency port of the circuit board.

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