A circular polarization positioning antenna device and a wearable device

Abstract

A circularly polarized positioning antenna device and a wearable device. The circularly polarized positioning antenna device comprises: a power division circuit, a first antenna and a second antenna arranged orthogonally. The power division circuit simplifies the overall structure of the circularly polarized antenna by feeding the two antennas, making it easier to implement on a wearable product, 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.

Description

Technical Field

[0001] The present application belongs to the field of antenna technology, and in particular relates to a circularly polarized positioning antenna device 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. Summary of the invention

[0003] The purpose of the present application is to provide a circular polarization positioning antenna device and a wearable device, aiming to solve the problem of low antenna positioning accuracy of existing wearable devices.

[0004] A first aspect of an embodiment of the present application provides a circularly polarized positioning antenna device, comprising:

[0005] A power division circuit, having a first output end and a second output end, wherein the first output end and the second output end output a first feed signal, and the second output end outputs a second feed signal, wherein the first feed signal and the second feed signal have equal amplitudes and a phase difference of 90°;

[0006] A first inverted-F antenna, connected to the first output terminal and receiving the first feeding signal;

[0007] A second inverted-F antenna is connected to the second output end and receives the second feed signal. The head end of the second inverted-F antenna is spaced apart at one side of the tail end of the first inverted-F antenna, and the first inverted-F antenna and the second inverted-F antenna form an angle to form two orthogonal mode excitations.

[0008] The above-mentioned circularly polarized positioning antenna device forms two orthogonal mode excitations by setting the positional relationship of two linearly polarized inverted F antennas. The two are matched with a power division circuit to realize equal amplitude and 90° phase difference feeding to form a circularly polarized antenna, and ensure that the axial ratio within the effective bandwidth is within 3dB. The realization of circular polarization ensures that the field shape of the receiver antenna in all directions on the radiation surface is round, and a circularly polarized hemispherical beam with excellent performance is obtained to achieve an ideal satellite search effect; in this way, by controlling the placement position of the two antennas and the control of the power supply phase, the radiation characteristics of the antenna with right-hand circular polarization can be realized. At the same time, the right-hand circularly polarized receiving antenna can reduce the interference of the left-hand circularly polarized signal, which can suppress multipath reflection in engineering, thereby effectively improving the positioning accuracy.

[0009] In one of the embodiments, the first antenna is a first inverted-F antenna, the first antenna having a first long side, a first end and a second end, one end of the first long side connected to the first end serves as the head end of the first inverted-F antenna, the other end of the first long side serves as the tail end of the first inverted-F antenna, one of the first end and the second end is connected to the first output end, and the other is used for grounding.

[0010] In one of the embodiments, the second antenna is a second inverted-F antenna, the second antenna having a second long side, a third end and a fourth end, one end of the second long side connected to the third end serves as the head end of the second inverted-F antenna, the other end of the second long side serves as the tail end of the second inverted-F antenna, one of the third end and the fourth end is connected to the second output end, and the other is used for grounding.

[0011] In one of the embodiments, the lengths of the first long side and the second long side correspond to the operating wavelength of the circular polarization positioning antenna device.

[0012] One of the embodiments further includes a dielectric substrate, and the first antenna and the second antenna are vertically arranged on the same surface of the dielectric substrate.

[0013] In one embodiment, the power dividing circuit is a Wilkinson power divider or a T-type power divider; or

[0014] The power division circuit includes a first input terminal, a second input terminal, the first output terminal and the second output terminal, wherein two first capacitors are connected in series between the first input terminal and the second input terminal, two second capacitors are connected in series between the first output terminal and the second output terminal, a first inductor is connected in series between the first input terminal and the first output terminal, a second inductor is connected in series between the second input terminal and the second output terminal, and a third inductor is connected between the common end of the two first capacitors and the common end of the two second capacitors.

[0015] In one embodiment, the first antenna and the second antenna are respectively symmetrical coupled CHIP antennas; or the first antenna and the second antenna are respectively symmetrical linearly polarized PATCH antennas.

[0016] In one embodiment, the angle ranges from 75° to 105°.

[0017] In one of the embodiments, an inductor is loaded on the first inverted-F antenna and / or the second inverted-F antenna.

[0018] A second aspect of an embodiment of the present application provides a wearable device, comprising a circuit board and the circularly polarized positioning antenna device as described above, wherein the input end of the power division circuit is connected to the radio frequency port of the circuit board, and the power division circuit divides the feed signal provided by the radio frequency port into the first feed signal and the second feed signal.

[0019] The above-mentioned wearable device adopts all the embodiments of the above-mentioned circularly polarized positioning antenna device, 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

[0020] Figure 1 A top view of a circularly polarized positioning antenna device provided in an embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the structure of a circularly polarized positioning antenna device provided in an embodiment of the present invention;

[0022] Figure 3 A circuit diagram of a power division circuit provided by an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of S parameters of a circularly polarized positioning antenna device provided in an embodiment of the present invention;

[0024] Figure 5 A three-dimensional radiation pattern of a circularly polarized positioning antenna device provided in an embodiment of the present invention;

[0025] Figure 6 A two-dimensional four-axis ratio simulation diagram of the phi=0° and 90° sections of the circularly polarized positioning antenna device provided in an embodiment of the present invention;

[0026] Figure 7 The invention provides a two-dimensional radiation pattern of right-hand circular polarization gain at phi=0° and 90° sections of the circular polarization positioning antenna device provided in an embodiment of the invention. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] See also Figure 1 The circularly polarized positioning antenna device that can be used for wearable devices provided in an embodiment of the present application includes a power division circuit 10, a first antenna 11 and a second antenna 12.

[0032] The power division circuit 10 has a first output terminal 3 and a second output terminal 4, the first output terminal 3 outputs a first feed signal, the second output terminal 4 outputs a second feed signal, the first feed signal and the second feed signal have equal amplitude and a phase difference of 90°; the first antenna 11 is connected to the first output terminal 3 of the power division circuit 10 and receives the first feed signal; the second antenna 12 is connected to the second output terminal 4 of the power division circuit 10 and receives the second feed signal, the head end 121A of the second antenna 12 is spaced apart at one side of the tail end 111B of the first antenna, and the first antenna 11 is spaced apart from the second antenna 12. The two antennas 12 are at an angle α, forming two orthogonal mode excitations, which can make the distributed current achieve equal amplitude and a phase difference of 90° at the required working frequency. Specifically, the distributed current phase can be delayed by 90° in a counterclockwise direction on the front side of the dielectric substrate 100, so that the polarization mode of the positioning antenna is right-hand circular polarization, and the axial ratio within the effective bandwidth is guaranteed to be within 3dB. The realization of circular polarization ensures that the field shape of the receiver antenna in all directions on the radiation surface is round, and a circularly polarized hemispherical beam with excellent performance is obtained, achieving an ideal satellite search effect.

[0033] In one embodiment, the angle α between the first antenna 11 and the second antenna 12 on the front surface of the dielectric substrate 100 is in the range of 70° to 110°. Experiments show that it can still radiate good circularly polarized waves. The angle α may preferably be in the range of 75° to 105°.

[0034] In one embodiment, the first antenna 11 is arranged along a first direction x, and the second antenna 12 is arranged along a second direction y perpendicular to the first direction x, that is, the angle α between the first inverted F antenna 11 and the second inverted F antenna 12 is 90°. Figure 1 As shown, when looking down at the front of the dielectric substrate 100, the second antenna 12 needs to be located in the clockwise direction (i.e., on the right) of the first antenna 11 to ensure that when the first antenna 11 and the second antenna 12 resonate near the operating frequency, such as the GPS (Global Positioning System) L1 band 1.575GHz or the L5 band 1.176GHz, the current amplitudes of the first antenna 11 and the second antenna 12 are equal, and the current phase of the first antenna 11 is 90° earlier than the current phase on the second antenna 12, so that right-hand circular polarization radiation can be achieved. In other embodiments, the angle α can be between 75° and 105°.

[0035] See also Figure 2 In some embodiments, the first antenna 11 and the second antenna 12 are vertically arranged on the same surface (front side) of the dielectric substrate 100. For example, the first antenna 11 and the second antenna 12 are perpendicular to the dielectric substrate 100, and the dielectric substrate 100 is a ground plane for grounding the circularly polarized positioning antenna device.

[0036] In one embodiment, the first antenna 11 is a (first) inverted F antenna, and the first antenna 11 has a first long side 111, a first end 112 and a second end 113. The end of the first long side 111 connected to the first end 112 serves as the head end 111A of the first antenna 11, and the other end of the first long side 111 serves as the tail end 111B of the first antenna 11. One of the first end 112 and the second end 113 is connected to the first output end 3 of the power divider circuit 10 for receiving the first feeding signal, and the other is used for grounding. That is, the two ends 112 and 113 connected to the side of the first long side 111 in the first antenna 11 in this embodiment can be used as a grounding end for grounding, and the other can be used as a feeding end for feeding according to the current distribution, size or excellent performance. The two implementations have similar performances and can be selected according to needs when applied, and are not limited here.

[0037] Similarly, the second antenna 12 is a (second) inverted F antenna, and the second antenna 12 has a second long side 121, a third end 122 and a fourth end 123. One end of the second long side 121 connected to the third end 122 serves as the head end 121A of the second antenna 12, and the other end of the second long side 121 serves as the tail end 121B of the second antenna 12. One of the third end 122 and the fourth end 123 is connected to the second output end 4 of the power division circuit 10 for receiving the second feeding signal, and the other is used for grounding. That is, the two ends 122 and 123 connected to the side of the second long side 121 in the second inverted F antenna 12 in this embodiment can be used as a grounding end for grounding, and the other can be used as a feeding end for feeding according to current distribution, size or excellent performance. The two implementations have similar performances and can be selected as needed when applied, and are not limited here.

[0038] exist Figure 1 In the example, the first end 112 is connected to the head end 111A of the first antenna 11, the second end 113 is closer to the head end 111A of the first antenna 11 than the tail end 111B thereof, the third end 122 is connected to the head end 121A of the second antenna 12, and the fourth end 123 is closer to the head end 121A of the second antenna 12 than the tail end 121B thereof. It can be understood that this scheme is only an example of one implementation scheme. In other implementation schemes, the positions where the first end 112 and the second end 113 are connected to the first long side 111, and the positions where the third end 122 and the fourth end 123 are connected to the second long side 121 can be adjusted according to the requirements of their radiation performance and equipment space. Figure 1 The examples are not intended to limit the technical solutions of this application.

[0039] In the present application, a coupling slot is formed between the end 111B of the first inverted F antenna 11 and the head end 121A of the second antenna 12, and the coupling slot is adjusted to adjust the coupling degree between the first antenna 11 and the second inverted F antenna 12. Moreover, it is easier to match and tune by using slot coupling feeding, and by adjusting the spacing of the coupling slots, the coupling degree can be adjusted to achieve matching and tuning of the antenna.

[0040] The lengths of the first long side 111 and the second long side 121 correspond to the working wavelength of the circular polarization positioning antenna device. For example, the equivalent lengths of the first long side 111 and the second long side 121 are substantially equal to the working wavelength of the circular polarization positioning antenna device, or the equivalent lengths of the first long side 111 and the second long side 121 are substantially equal to 1 / 4 wavelength of the working wavelength of the circular polarization positioning antenna device, to ensure that the antenna resonates at the required frequency. It should be noted that although the equivalent lengths of the first long side 111 and the second long side 121 are substantially equal to 1 or 1 / 4 working wavelength, in order to ensure the realization of degenerate mode separation, the first long side 111 and the second long side 121 are of unequal lengths.

[0041] In one embodiment, the first long side 111 and the second long side 121 are straight strips. In other embodiments, due to the limitation of the equipment space, the first long side 111 and / or the second long side 121 may be curved with a certain arc in the actual arrangement, but it does not affect the arrangement along one direction. In addition, the first long side 111 and / or the second long side 121 may also extend other branches outside the main body to help increase the antenna's gain, axial ratio and other performances, for example, branches are arranged perpendicular to the dielectric substrate 100, and branches are arranged parallel to the dielectric substrate 100.

[0042] In one embodiment, the first antenna 11 and / or the second antenna 12 are loaded with an inductor (not shown), and the inductor is a concentrated inductor or a distributed inductor. In this embodiment, the inductor is mainly used to extend the equivalent length of the first antenna to reduce the size of the positioning antenna and effectively miniaturize the antenna. Optionally, the inductor can generally be a concentrated inductor, that is, an inductor, or a serpentine curved trace. The first antenna 11 and the second antenna 12 are three-dimensional antennas, patch ceramic antennas or microstrip antennas. It can be understood that in addition to adopting the branch antenna form of the inverted F antenna that has been presented, the circularly polarized positioning antenna device of the present application may have successfully tested branch antenna forms such as: symmetrical coupled chip (CHIP) antennas, or symmetrical linearly polarized patch (PATCH) antennas, which can be freely selected and adapted according to the available space and feasible environment. Compared with the fixed form of traditional circularly polarized antennas, CHIP antennas generally use ceramic as the base material, and the radiation structure of the antenna will be more diverse, such as a wire (metal strip) or a surface (metal plane); while circular or square PATCH antennas have new structures and diverse forms.

[0043] See also Figure 1 and Figure 3In one embodiment, the power division circuit 10 is a Wilkinson power divider or a T-type power divider; or it is composed of a discrete circuit with a lower price, and the power division circuit of the discrete circuit includes a first input terminal 1, a second input terminal 2, a first output terminal 3 and a second output terminal 4, wherein two first capacitors C1 and C2 are connected in series between the first input terminal 1 and the second input terminal 2, two second capacitors C3 and C4 are connected in series between the first output terminal 1 and the second output terminal 2, a first inductor L1 is connected in series between the first input terminal 1 and the first output terminal 3, a second inductor L2 is connected in series between the second input terminal 2 and the second output terminal 4, and a third inductor L3 is connected between the common terminal of the two first capacitors C1 and C2 and the common terminal of the two second capacitors C3 and C4. The first input terminal 1 of the power division circuit 10 is connected to the RF port of the GPS module of the circuit board, and the power division circuit 10 performs power distribution according to the feed signal provided by the RF port of the GPS module, outputs the first feed signal at the first output terminal 3, and outputs the second feed signal at the second output terminal 4.

[0044] The circularly polarized positioning antenna device as above uses antennas with the same structural form as branches, which is convenient for debugging and practical application. The form of branch antennas can be flexibly selected according to the internal environment of the wearable device, but the forms of the two branch antennas must be the same; the 90° phase difference power supply of the two antennas can be better guaranteed through the power division network.

[0045] from Figure 4 It can be seen that the circularly polarized positioning antenna device resonates at 1.575 GHz in the GPS L1 frequency band, and the impedance bandwidth (S11 <-6 dB) can completely cover the entire GPS-L1 frequency band (1575 ± 2 MHz), indicating that the positioning antenna effectively realizes right-hand circularly polarized radiation and has good reception of navigation satellite signals.

[0046] from Figure 5 It can be seen that when the above-mentioned positioning antenna operates in the L1 frequency band of GPS 1.575GHz, the above-mentioned positioning antenna can achieve the best circular polarization performance (that is, the minimum axial ratio) at a specific spatial angle (phi=0°, theta=0°). In the GPS L1 frequency band, the axial ratio is <5dB, indicating that the axial ratio characteristics of the above-mentioned positioning antenna are very good and meet the performance requirements of the positioning antenna.

[0047] from Figure 6 and Figure 7It can be seen that when the above-mentioned positioning antenna operates in the GPS-L1 frequency band of 1.575GHz, the top of the positioning antenna (phi=0°, theta=0°) achieves a maximum right-hand circular polarization directivity coefficient of 2.71dB. Under the same directivity coefficient, the satellite signal received by the circularly polarized antenna is 3dB higher than that received by the linearly polarized antenna. At the same time, it has a suppression function for interference signals. Therefore, the positioning effect of the above-mentioned positioning antenna is better than that of the traditional linearly polarized antenna.

[0048] The second aspect of the embodiment of the present application provides a wearable device, including a circuit board and a circularly polarized positioning antenna device as described above, wherein the input end of the power division circuit 10 is connected to the radio frequency port of the circuit board, and the power division circuit is divided into a first feeding signal and a second feeding signal according to the feeding signal provided by the radio frequency port.

[0049] The wearable device adopts all the embodiments of the circularly polarized positioning antenna device, and thus has at least all the beneficial effects of the embodiments, which will not be described one by one here. The wearable device positioning antenna can better receive navigation satellite signals, and the right-handed circularly polarized radiation generated 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.

[0050] 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 wearable device, characterized in that: It includes a circuit board and a circular polarization positioning antenna device, and the circular polarization positioning antenna device includes: A power division circuit, having a first output end and a second output end, wherein the first output end and the second output end output a first feed signal, and the second output end outputs a second feed signal, wherein the first feed signal and the second feed signal have equal amplitudes and a phase difference of 90°; A first antenna, coupled to the first output terminal and connected to the first feeding signal, wherein the first antenna is a first inverted-F antenna; a second antenna, coupled to the second output end and connected to the second feed signal, wherein the head end of the second antenna is arranged at a distance from one side of the tail end of the first antenna, and the first antenna and the second antenna form an angle to form two orthogonal mode excitations, and the second antenna is a second inverted F antenna; A dielectric substrate, the first antenna and the second antenna are vertically arranged on the same surface of the dielectric substrate, and the dielectric substrate is a grounding plate for grounding the circular polarization positioning antenna device; The input end of the power division circuit is connected to the RF port of the circuit board. The power division circuit outputs the first feed signal at the first output end and outputs the second feed signal at the second output end according to the feed signal provided by the RF port.

2. The wearable device according to claim 1, wherein: The first antenna has a first long side, a first end and a second end. One end of the first long side connected to the first end serves as the head end of the first inverted-F antenna, and the other end of the first long side serves as the tail end of the first inverted-F antenna. One of the first end and the second end is connected to the first output end, and the other is used for grounding.

3. The wearable device according to claim 2, characterized in that: The second antenna has a second long side, a third end and a fourth end. One end of the second long side connected to the third end serves as the head end of the second inverted-F antenna, and the other end of the second long side serves as the tail end of the second inverted-F antenna. One of the third end and the fourth end is connected to the second output end, and the other is used for grounding.

4. The wearable device according to claim 3, characterized in that: The lengths of the first long side and the second long side correspond to the working wavelength of the circular polarization positioning antenna device.

5. The wearable device according to any one of claims 1 to 4, characterized in that: The power dividing circuit is a Wilkinson power divider or a T-type power divider; or The power division circuit includes a first input terminal, a second input terminal, the first output terminal and the second output terminal, wherein two first capacitors are connected in series between the first input terminal and the second input terminal, two second capacitors are connected in series between the first output terminal and the second output terminal, a first inductor is connected in series between the first input terminal and the first output terminal, a second inductor is connected in series between the second input terminal and the second output terminal, and a third inductor is connected between the common end of the two first capacitors and the common end of the two second capacitors.

6. The wearable device according to claim 1, wherein: The first antenna and the second antenna are respectively symmetrical coupled CHIP antennas; or the first antenna and the second antenna are respectively symmetrical linearly polarized PATCH antennas.

7. The wearable device according to claim 1, wherein: The angle ranges from 75° to 105°.

8. The wearable device according to any one of claims 1 to 4, characterized in that: The first antenna and / or the second antenna is loaded with an inductor.

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