A Dual-Polarization / Circular-Polarization Split Ring Antenna Based on Common Mode and Differential Mode

Abstract

A dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode, comprising a dielectric substrate, on which a split radiation ring, a common-mode feeding structure and a differential-mode feeding structure are printed; the split radiation ring is the antenna radiation structure, including a pair of split narrow slits and a split wide slit; the differential-mode feeding structure has a first port, and the common-mode feeding structure has a second port; the differential-mode of the split radiation ring is excited by the differential-mode feeding structure, and the common-mode of the split radiation ring is excited by the common-mode feeding structure, so that the common-mode and the differential-mode work simultaneously in the split radiation ring; when different signals are input to the first port and the second port, dual-polarization radiation is realized; when the same signals are input to the first port and the second port, circular-polarization radiation is realized. The present invention can solve the problem that the traditional dual-polarization antenna needs to introduce a 90° phase shift to realize circular-polarization radiation, simplifies the feeding structure of the traditional dual-fed antenna to realize circular-polarization radiation, and has good application prospects in the field of wireless communication.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communication, relates to an antenna structure, and particularly relates to a dual-polarization / circular-polarization slot ring antenna based on common mode and differential mode. Background Art

[0002] With the rapid development of wireless communication technology, traditional single linear polarization antennas are no longer suitable for transmitting and receiving signals of different polarizations. Dual-polarization antennas and circular-polarization antennas have received more and more research and exploration due to their excellent characteristics, such as reducing the multipath effect between the transmitting antenna and the receiving antenna. Therefore, dual-polarization antennas and circular-polarization antennas are widely used in various wireless systems. Traditional dual-polarization antennas need to be fed with equal amplitude and 90° phase difference at two ports to achieve circular polarization radiation. Therefore, an additional phase shift structure or device needs to be introduced to achieve a 90° phase shift, which increases the occupied space of the antenna feeding structure and the design complexity. For example, the above architecture is adopted in patent CN108470979A, etc. Summary of the Invention

[0003] In order to overcome the above disadvantages of the prior art, the purpose of the present invention is to provide a dual-polarization / circular-polarization slot ring antenna based on common mode and differential mode, which can achieve circular polarization radiation by feeding the dual-polarization antenna with equal amplitude and in-phase. It can solve the problem that traditional dual-polarization antennas need to introduce a 90° phase shift to achieve circular polarization radiation, simplifies the feeding structure of traditional dual-feed antennas to achieve circular polarization radiation, and has good application prospects in the field of wireless communication.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0005] A dual-polarization / circular-polarization slot ring antenna based on common mode and differential mode, comprising a dielectric substrate, on which an open radiation ring, a common mode feeding structure, and a differential mode feeding structure are printed; the open radiation ring is an antenna radiation structure, comprising a pair of open narrow slits and an open wide slit; the differential mode feeding structure has a first port, and the common mode feeding structure has a second port;

[0006] The differential mode of the open radiation ring is excited by the differential mode feeding structure, and the common mode of the open radiation ring is excited by the common mode feeding structure, so that the common mode and the differential mode work simultaneously on the open radiation ring;

[0007] When different signals are input to the first port and the second port, dual-polarization radiation is achieved;

[0008] When the same signals are input to the first port and the second port, circular polarization radiation is achieved.

[0009] In one embodiment, the open radiation ring is an open loop, printed on the upper surface of the dielectric substrate, and symmetric about the Y axis.

[0010] In one embodiment, the differential-mode feeding structure is a bent stub printed on the lower surface of the dielectric substrate.

[0011] In one embodiment, the common-mode feeding structure is composed of a straight open-circuit stub and an open small loop. The straight open-circuit stub is printed on the lower surface of the dielectric substrate, and the open small loop is printed on the upper surface of the dielectric substrate.

[0012] In one embodiment, the first port is located on the side surface of the dielectric substrate. Differential-mode feeding is achieved by connecting the differential-mode feeding structure and the open radiation loop to the inner core and outer conductor of the coaxial cable respectively; the second port is located on the side surface of the dielectric substrate. Common-mode feeding is achieved by connecting the straight open-circuit stub and the open radiation loop to the inner core and outer conductor of the coaxial cable respectively.

[0013] In one embodiment, both the straight open-circuit stub and the open small loop are symmetric about the Y axis. The open small loop is an open loop with a pair of open slits. The width W4 of the pair of open slits in the open small loop and the width W2 of the straight open-circuit stub have the following relationship: W2 / W4 ∈ [1.6, 2].

[0014] In one embodiment, the sum of the horizontal stub length L4 and the vertical stub length L5 at the end of the differential-mode feeding structure has an error of no more than 5% from the length L2 of the straight open-circuit stub. That is: L2 / (L4 + L5) ∈ [0.95, 1.05].

[0015] In one embodiment, the length L0 of the dielectric substrate is 52 mm, and the width W0 is 52 mm; the width L1 of the horizontal side (i.e., the X-direction side) of the open radiation loop is 8.5 mm, and the width W1 of the vertical side (i.e., the Y-direction side) is 5.5 mm; the length L2 of the straight open-circuit stub is 24 mm, and the width W2 is 1.8 mm; the length L3 of the vertical side (i.e., the Y-direction side) of the open small loop is 10 mm, and the length W3 of the horizontal side (i.e., the X-direction side) is 10 mm; the horizontal stub length L4 of the differential-mode feeding structure is 17.2 mm, the vertical stub length L5 at the end of the differential-mode feeding structure is 5.6 mm, the width W4 of the open slit 321 is 1 mm, and the width W5 of the open narrow slit is 0.3 mm.

[0016] In one embodiment, when the open-loop antenna has a center frequency of 2.7 GHz, the relative operating bandwidth of dual polarization and circular polarization is not less than 51.8%. The common bandwidth includes the impedance bandwidth with a reflection coefficient less than -10 dB at both the first port and the second port and the circular polarization bandwidth with an axial ratio less than 3 dB.

[0017] In one embodiment, both the dual polarization and the circular polarization are bidirectional radiation.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] By respectively exciting two orthogonal antenna operating modes with a 90° phase difference through two ports, the present invention realizes dual-polarization radiation and circular-polarization radiation of the antenna. When the first port A is fed, the differential-mode operating mode of this antenna can be excited. When the second port B is fed, the common-mode operating mode of this antenna can be excited. The common-mode operating mode and the differential-mode operating mode of this antenna are polarization orthogonal, and dual-polarization radiation can be realized. At the same time, the common-mode operating mode and the differential-mode operating mode have a 90° phase difference. Therefore, when the antenna is fed with equal amplitude and in-phase at the two ports, the mode intensities of the common-mode operating mode and the differential-mode operating mode are the same, and circular-polarization radiation of the antenna can be realized. This antenna solves the problem that traditional dual-polarization antennas need to introduce a 90° phase shift to realize circular-polarization radiation, and simplifies the feeding structure of traditional dual-fed antennas to realize circular-polarization radiation. Description of the Drawings

[0020] Figure 1 It is a perspective view of the three-dimensional structure of a dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode of the present invention.

[0021] Figure 2 It is a bottom view of a dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode of the present invention.

[0022] Figure 3 It is a reflection coefficient curve graph of the first port and the second port of a dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode of the present invention.

[0023] Figure 4 It is a transmission coefficient curve graph of the first port and the second port of a dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode of the present invention.

[0024] Figure 5 It is a circular polarization axial ratio curve graph of a dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode of the present invention.

[0025] Figure 6 It is a gain curve graph of a dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode of the present invention.

[0026] Figure 7 It is a dual-polarization radiation pattern of a dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode of the present invention.

[0027] Figure 8 It is a circular polarization radiation pattern of a dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode of the present invention.

[0028] In the figure: 1, dielectric substrate; 2, open radiation loop; 21, open narrow slit; 22, open wide slit; 3, common-mode feeding structure; 31, straight open stub; 32, open small loop; 321, open slit; 4, differential-mode feeding structure; A, first port; B, second port. Detailed implementation

[0029] In order to make the objectives, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but it shall not be used as a basis for any limitation to the present invention.

[0030] The present invention is a dual-polarization / circular-polarization open-loop antenna based on common mode and differential mode. Herein, "dual-polarization / circular-polarization" means that under the structure of the present invention, when different signals are input to the two ports, dual-polarization radiation can be achieved, and when the same signals are input to the two ports, circular-polarization radiation can be achieved.

[0031] Specifically, as Figure 1 and Figure 2 shown, the present invention includes a dielectric substrate 1, and an open radiation loop 2, a common-mode feeding structure 3, and a differential-mode feeding structure 4 printed on the dielectric substrate 1. A first port A and a second port B are provided on the dielectric substrate 1. In the present invention, the common-mode feeding structure 3 and the differential-mode feeding structure 4 are the feeding networks of the antenna, and the first port A and the second port B are the feeding ports of the antenna. The open radiation loop 2 is the radiation structure of the antenna, and includes a pair of open narrow slits 21 and an open wide slit 22. Among them, the antenna excites the differential-mode of the open radiation loop 2 through the differential-mode feeding structure 4, and excites the common-mode of the open radiation loop 2 through the common-mode feeding structure 3, so that the common-mode and the differential-mode work simultaneously in the open radiation loop 2.

[0032] In the present invention, the differential mode and the common mode of the antenna excited by the first port A and the second port B are polarization orthogonal. Therefore, when different signals are input to the two ports, dual-polarization radiation can be achieved.

[0033] Furthermore, since the common-mode and the differential-mode have a 90° phase difference, circular-polarization radiation can be achieved when the first port A and the second port B are fed with equal amplitude and in-phase. Equal amplitude and in-phase feeding means that the signals input to the two ports have the same amplitude and phase.

[0034] In some embodiments of the present invention, the material of the dielectric substrate 1 of the antenna is FR4, and the thickness is 1.6 mm.

[0035] In some embodiments of the present invention, the differential-mode feeding structure 4 is a bent stub printed on the lower surface of the dielectric substrate 1.

[0036] In some embodiments of the present invention, the common-mode feeding structure 3 is composed of a straight open stub 31 and an open-loop small ring 32. The straight open stub 31 is printed on the lower surface of the dielectric substrate 1, and the open-loop small ring 32 is printed on the upper surface of the dielectric substrate 1.

[0037] In some embodiments of the present invention, the first port A is located on the side surface of the dielectric substrate 1, and differential-mode feeding is realized by connecting the differential-mode feeding structure 4 and the open-radiating ring 2 through the inner core and outer conductor of the coaxial cable respectively; the second port B is located on the side surface of the dielectric substrate 1, and common-mode feeding is realized by connecting the straight open stub 31 and the open-radiating ring 2 through the inner core and outer conductor of the coaxial cable respectively.

[0038] In some embodiments of the present invention, the open-loop small ring 32 is an open-loop with a pair of open slits 321. The straight open stub 31 and the open-loop small ring 32 are both symmetric about the Y-axis. The open-loop small ring 32 is an open-loop with a pair of open slits 321. The width W4 of the pair of open slits 321 in the open-loop small ring 32 and the width W2 of the straight open stub 31 on the lower surface of the dielectric substrate 1 in the common-mode feeding structure 3 have the following relationship: W2 / W4 ∈ [1.6, 2].

[0039] In some embodiments of the present invention, the sum of the horizontal branch length L4 and the end vertical branch length L5 of the differential-mode feeding structure 4 has an error of no more than 5% from the length L2 of the straight open stub 31. That is: L2 / (L4 + L5) ∈ [0.95, 1.05].

[0040] In some embodiments of the present invention, Table 1 below gives a specific structural dimension.

[0041] Table 1

[0042] Structure <![CDATA[L0]]> <![CDATA[L1]]> <![CDATA[L2]]> <![CDATA[L3]]> <![CDATA[L4]]> <![CDATA[L5]]> Dimensions (mm) 52 8.5 24 10 17.2 5.6 Structure <![CDATA[W0]]> <![CDATA[W1]]> <![CDATA[W2]]> <![CDATA[W3]]> <![CDATA[W4]]> <![CDATA[W5]]> Dimensions (mm) 52 5.5 1.8 10 1 0.3

[0043] Wherein, L0 is the length of the dielectric substrate 1, W0 is the width of the dielectric substrate 1; L1 is the width of the horizontal side, i.e., the X-direction side, of the open-radiating ring, W1 is the width of the vertical side, i.e., the Y-direction side, of the open-radiating ring; L2 is the length of the straight open stub 31, W2 is the length of the straight open stub 31; L3 is the length of the vertical side, i.e., the Y-direction side, of the open-loop small ring 32, W3 is the length of the horizontal side, i.e., the X-direction side; L4 is the horizontal branch length of the differential-mode feeding structure 4, L5 is the end vertical branch length of the differential-mode feeding structure 4, W4 is the width of the open slit 321, and W5 is the width of the open narrow slit 21.

[0044] When the open - loop antenna of the present invention has a center frequency of 2.7 GHz, the relative operating bandwidth of dual - polarization and circular - polarization is not less than 51.8%. The common bandwidth includes the impedance bandwidth with the reflection coefficient of the first port A and the second port B less than - 10 dB and the circular - polarization bandwidth with the axial ratio less than 3 dB.

[0045] According to the size parameters in Table 1 above, the effect of the present invention can be further illustrated in combination with the simulation results:

[0046] As Figure 3 shown, it is the reflection - coefficient curve graph of the first port and the second port of a dual - polarization / circular - polarization open - loop antenna based on common - mode and differential - mode in this embodiment. The common operating frequency band with the reflection coefficient of the dual - port less than - 10 dB is 2.0 - 3.4 GHz.

[0047] As Figure 4 shown, it is the transmission - coefficient curve graph of the first port and the second port of a dual - polarization / circular - polarization open - loop antenna based on common - mode and differential - mode in this embodiment. The transmission coefficient between the dual - ports is less than - 20 dB within the operating frequency band of 2.0 - 3.4 GHz. Therefore, the dual - polarization operating bandwidth of the antenna is 2.0 - 3.4 GHz.

[0048] As Figure 5 shown, it is the circular - polarization axial - ratio curve graph of a dual - polarization / circular - polarization open - loop antenna based on common - mode and differential - mode in this embodiment. The 3 - dB axial - ratio bandwidth of this antenna is 1.9 - 3.4 GHz. Therefore, the common operating bandwidth of the dual - polarization and circular - polarization of this antenna is 2.0 - 3.4 GHz, the center frequency is 2.7 GHz, and the relative bandwidth is 51.8%.

[0049] As Figure 6 shown, it is the gain curve graph of a dual - polarization / circular - polarization open - loop antenna based on common - mode and differential - mode in this embodiment. The gain within the operating frequency band of this circular - polarization antenna is greater than 3.2 dB.

[0050] As Figure 7 shown, it is the dual - polarization radiation pattern of a dual - polarization / circular - polarization open - loop antenna based on common - mode and differential - mode in this embodiment. This antenna has the ability of bi - directional dual - polarization radiation.

[0051] As Figure 8 shown, it is the circular - polarization radiation pattern of a dual - polarization / circular - polarization open - loop antenna based on common - mode and differential - mode in this embodiment. This antenna has the ability of bi - directional circular - polarization radiation.

[0052] Therefore, this antenna has the advantages of simple structure, wide frequency band, and can realize dual - polarization / circular - polarization radiation, etc. It simplifies the feeding structure for realizing circular - polarization radiation of the traditional dual - polarization antenna and is suitable for use in the future wireless communication field. And in the present invention, both dual - polarization and circular - polarization can be bi - directional radiation.

[0053] The above has introduced in detail a dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode, and elaborated and implemented the principle and implementation manner of the present invention by applying detailed structural design parameters. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode, characterized in that, It includes a dielectric substrate (1), on which an open radiation loop (2), a common-mode feeding structure (3) and a differential-mode feeding structure (4) are printed; the open radiation loop (2) is an antenna radiation structure, which includes a pair of open narrow slits (21) and an open wide slit (22); the differential-mode feeding structure (4) has a first port (A), and the common-mode feeding structure (3) has a second port (B); The common-mode feeding structure (3) is composed of a straight open-circuit stub (31) and an open small loop (32). The straight open-circuit stub (31) is printed on the lower surface of the dielectric substrate (1), and the open small loop (32) is printed on the upper surface of the dielectric substrate (1); the first port (A) is located on the side surface of the dielectric substrate (1), and differential-mode feeding is realized by connecting the differential-mode feeding structure (4) and the open radiation loop (2) respectively through the inner core and outer conductor of a coaxial cable; the second port (B) is located on the side surface of the dielectric substrate (1), and common-mode feeding is realized by connecting the straight open-circuit stub (31) and the open radiation loop (2) respectively through the inner core and outer conductor of a coaxial cable; The differential-mode feeding structure (4) is used to excite the differential-mode of the open radiation loop (2), and the common-mode feeding structure (3) is used to excite the common-mode of the open radiation loop (2), so that the common-mode and differential-mode work simultaneously in the open radiation loop (2); When different signals are input to the first port (A) and the second port (B), dual-polarization radiation is realized; When the same signals are input to the first port (A) and the second port (B), circular polarization radiation is realized.

2. The dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode according to claim 1, wherein The open radiation loop (2) is an open loop, printed on the upper surface of the dielectric substrate (1), and is symmetric about the Y axis.

3. The dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode according to claim 1, characterized in that The differential-mode feeding structure (4) is a bent stub printed on the lower surface of the dielectric substrate (1).

4. The dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode according to claim 1, wherein Both the straight open-circuit stub (31) and the open small loop (32) are symmetric about the Y axis. The open small loop (32) is an open loop with a pair of open slits (321). The width W4 of the pair of open slits (321) in the open small loop (32) and the width W2 of the straight open-circuit stub (31) have the following relationship: W2 / W4 ∈ [1.6, 2].

5. The dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode according to claim 4, characterized in that The sum of the horizontal stub length L4 and the vertical stub length L5 at the end of the differential-mode feeding structure (4) has an error of no more than 5% from the length L2 of the straight open-circuit stub (31).

6. The dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode according to claim 4, wherein The length L0 of the dielectric substrate (1) is 52 mm, and the width W0 is 52 mm; the width L1 of the horizontal side (i.e., the X-direction side) of the open radiation loop is 8.5 mm, and the width W1 of the vertical side (i.e., the Y-direction side) is 5.5 mm; the length L2 of the straight open-circuit stub (31) is 24 mm, and the width W2 is 1.8 mm; the length L3 of the vertical side (i.e., the Y-direction side) of the open small loop (32) is 10 mm, and the length W3 of the horizontal side (i.e., the X-direction side) is 10 mm; the horizontal stub length L4 of the differential-mode feeding structure (4) is 17.2 mm, the vertical stub length L5 at the end of the differential-mode feeding structure (4) is 5.6 mm, the width W4 of the open slit 321 is 1 mm, and the width W5 of the open narrow slit (21) is 0.3 mm.

7. The dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode according to claim 1, characterized in that When the center frequency of the split-ring antenna is 2.7 GHz, the relative operating bandwidth of dual polarization and circular polarization is not less than 51.8%. The common bandwidth includes the impedance bandwidth with the reflection coefficients of the first port (A) and the second port (B) less than -10 dB and the circular polarization bandwidth with the axial ratio less than 3 dB.

8. The dual-polarization / circular-polarization split-ring antenna based on common mode and differential mode according to claim 1, wherein Both the dual polarization and the circular polarization are bidirectional radiation.

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