A planar dual circularly polarized antenna based on orthogonal magnetic dipoles

Abstract

The application discloses a planar dual-circularly polarized antenna based on a quadrature magnetic dipole, and relates to the technical field of dual-circularly polarized antennas. The antenna comprises a first dielectric substrate, a metal ground layer, a second dielectric substrate and a third dielectric substrate which are stacked from top to bottom. The metal ground layer is provided with a first coupling slot and a second coupling slot in the middle. The first dielectric substrate is provided with two first metallized through holes and two second metallized through holes. A first metal strip is connected with the metal ground layer through the two first metallized through holes, and the two first metallized through holes are rotationally symmetrical about the first coupling slot. The position relationship between the second metallized through hole and the second coupling slot is the same as the position relationship between the second metallized through hole and the second coupling slot. The coupling slots and the microstrip feed line are coupled to excite the metallized through holes and the metal strip, and generate right-handed circularly polarized radiation waves or left-handed circularly polarized radiation waves in the direction upwards. The application has the performance advantages of low profile, simple structure and wide axial ratio bandwidth.

Description

Technical Field

[0001] The present invention relates to the technical field of dual circular polarization antennas, and in particular to a planar dual circular polarization antenna based on orthogonal magnetic dipoles. Background Art

[0002] With the rapid development of fifth-generation mobile communication technology, the millimeter wave frequency band is increasingly being utilized to provide high data rates and broad spectrum resources. Compared to linearly polarized antennas, which can only receive waves with the same linear polarization, circularly polarized antennas can receive both linearly and circularly polarized waves, thus avoiding polarization loss caused by polarization mismatch between the transmitting and receiving antennas. Circularly polarized antennas offer excellent performance in addressing polarization mismatch, suppressing rain and fog interference, and eliminating the Faraday effect. Therefore, the research and design of circularly polarized antennas for millimeter wave frequencies is crucial. Compared to conventional circularly polarized antennas, dual circularly polarized antennas can increase the channel capacity of wireless communication links. However, due to the high difficulty of design and implementation, research on planar dual circularly polarized antennas for the millimeter wave band is relatively limited. Currently, the implementation of dual circularly polarized antennas primarily relies on the antenna's feed network to provide phase difference, which results in a complex feed network, increased transmission loss, and increased antenna size. Antennas that rely on the inherent characteristics of the unit antenna to achieve dual circular polarization performance are few and far between. The dual circularly polarized antenna proposed in the present invention does not rely on a complex feeding network, but only relies on the characteristics of the unit antenna itself to achieve dual circularly polarized radiation, which is of great significance. Summary of the Invention

[0003] The object of the present invention is to provide a planar dual circularly polarized antenna based on orthogonal magnetic dipoles, which has the performance advantages of low profile, simple structure and wide axial ratio bandwidth.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A planar dual circularly polarized antenna based on orthogonal magnetic dipoles, comprising: a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a metal layer, a first metal strip, a second metal strip, a first microstrip feed line, and a second microstrip feed line;

[0006] The first dielectric substrate, the metal layer, the second dielectric substrate and the third dielectric substrate are stacked from top to bottom; a first coupling slot and a second coupling slot are provided in the middle of the metal layer, intersecting at an angle of 90 degrees;

[0007] The first metal strip and the second metal strip are located on the upper surface of the first dielectric substrate, and the first metal strip and the second metal strip overlap at the center portion of the first dielectric substrate; the first dielectric substrate is provided with two first metallized through-holes and two second metallized through-holes, the first metal strip is connected to the metal layer via the two first metallized through-holes, and the second metal strip is connected to the metal layer via the two second metallized through-holes; the two first metallized through-holes are closely adjacent to the edges of the first coupling slot, and the two first metallized through-holes are rotationally symmetric about the first coupling slot; the two second metallized through-holes are closely adjacent to the edges of the second coupling slot, and the two second metallized through-holes are rotationally symmetric about the second coupling slot;

[0008] The first microstrip feed line is located on the lower surface of the second dielectric base layer; the second microstrip feed line is located on the lower surface of the third dielectric base layer;

[0009] The first coupling slot is coupled to the first microstrip feed line, and is used to excite the first metallized through hole and the first metal strip, and is capable of generating an upward left-handed circularly polarized radiation wave;

[0010] The second coupling slot is coupled to the second microstrip feed line, and is used to excite the second metallized through hole and the second metal strip, and can generate an upward right-handed circularly polarized radiation wave.

[0011] Preferably, the first microstrip feed line is provided with a first feeding port, and when the first feeding port is feeding, the first microstrip feed line is coupled with the first coupling slot; the second microstrip feed line is provided with a second feeding port; when the second feeding port is feeding, the second microstrip feed line is coupled with the second coupling slot.

[0012] Optionally, the antenna is a three-layer PCB structure.

[0013] Optionally, a height of the first metallized through hole is the same as a thickness of the first dielectric substrate; a height of the second metallized through hole is the same as a thickness of the first dielectric substrate.

[0014] Optionally, the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all Rogers 5880 dielectric substrates.

[0015] Preferably, the first metal strip is an I-shaped structure as a whole, the "vertical" part in the middle of the "I" shape is parallel to the first coupling gap and is located in the middle position of the first dielectric substrate; the second metal strip is an I-shaped structure as a whole, the "vertical" part in the middle of the "I" shape is parallel to the second coupling gap and is located in the middle position of the first dielectric substrate.

[0016] Optionally, the dielectric constants of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all 2.2, and the loss angles are all tanδ=0.0009.

[0017] Optionally, the lengths of the first metal strip and the second metal strip are both half the wavelength corresponding to the circular polarization center frequency.

[0018] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0019] A first coupling slot and a second coupling slot are provided in the middle of the metal stratum; two first metallized through holes and two second metallized through holes are provided in the first dielectric substrate; a first metal strip is connected to the metal stratum via the two first metallized through holes, and the two first metallized through holes are rotationally symmetrical about the first coupling slot; the positional relationship between the second metallized through hole and the second coupling slot is the same as the positional relationship between the second metallized through hole and the second coupling slot; the coupling slot and the microstrip feeder couple the excitation metallized through hole and the metal strip, and generate an upward right-handed circularly polarized radiation wave or a left-handed circularly polarized radiation wave; the present invention has the performance advantages of low profile, simple structure and wide axial ratio bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0022] Figure 2 Schematic diagram of the overall structure of the first dielectric substrate of the present invention;

[0023] Figure 3 Schematic diagram of structural parameters of the first metal strip and the second metal strip of the present invention;

[0024] Figure 4 Schematic diagram of structural parameters of the first microstrip feeder of the present invention;

[0025] Figure 5 is a top view of the first microstrip feeder and the second microstrip feeder of the present invention;

[0026] Figure 6 is a cross-sectional view of the present invention;

[0027] Figure 7Schematic diagram of S parameters of the present invention;

[0028] Figure 8 Schematic diagram of S21 parameters of the present invention;

[0029] Figure 9 1 is a parameter diagram of the antenna axial ratio when feeding at the first feeding port of the present invention;

[0030] Figure 10 The radiation pattern of the antenna in the xoz plane at 32 GHz when the first feeding port is fed according to the present invention;

[0031] Figure 11 The radiation pattern of the antenna in the yoz plane at 32 GHz when the first feeding port is fed;

[0032] Figure 12 1 is a parameter diagram of the antenna axial ratio when feeding at the second feeding port of the present invention;

[0033] Figure 13 The radiation pattern of the antenna in the xoz plane at a frequency of 32 GHz when the second feeding port is fed;

[0034] Figure 14 This is the radiation pattern of the antenna in the yoz plane at a frequency of 32 GHz when the second feeding port is fed.

[0035] Explanation of symbols:

[0036] First dielectric substrate-1, second dielectric substrate-2, third dielectric substrate-3, first metal strip-4, first metallized through-hole-5, second metallized through-hole-6, second metal strip-7, metal ground layer-8, first coupling slot-9, second coupling slot-10, first feeding port-11, second feeding port-12, first microstrip feed line-13, second microstrip feed line-14. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0038] The object of the present invention is to provide a planar dual circularly polarized antenna based on orthogonal magnetic dipoles, which has the performance characteristics of low profile, simple structure and wide axial ratio bandwidth.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] like Figure 1 As shown, a spatial rectangular coordinate system o-xyz is assumed to include: an origin o, an x-axis, a y-axis, and a z-axis. The present invention provides a planar dual circularly polarized antenna based on orthogonal magnetic dipoles, comprising: a first dielectric substrate 1, a second dielectric substrate 2, a third dielectric substrate 3, a metal layer 8, a first metal strip 4, a second metal strip 7, a first microstrip feed line 13, and a second microstrip feed line 14.

[0041] The first dielectric substrate 1, the metal layer 8, the second dielectric substrate 2 and the third dielectric substrate 3 are stacked from top to bottom; a first coupling slot 9 and a second coupling slot 10 are provided in the middle of the metal layer 8 with an intersecting angle of 90 degrees.

[0042] The first metal strip 4 and the second metal strip 7 are located on the upper surface of the first dielectric substrate 1, and the first metal strip 4 and the second metal strip 7 overlap in the central portion of the first dielectric substrate 1; the first dielectric substrate 1 is provided with two first metallized through-holes 5 and two second metallized through-holes 6, the first metal strip 4 is connected to the metal layer 8 via the two first metallized through-holes 5, and the second metal strip 7 is connected to the metal layer 8 via the two second metallized through-holes 6; the two first metallized through-holes 5 are closely adjacent to the edge of the first coupling slot 9, and the two first metallized through-holes 5 are rotationally symmetric about the first coupling slot 9; the two second metallized through-holes 6 are closely adjacent to the edge of the second coupling slot 10, and the two second metallized through-holes 6 are rotationally symmetric about the second coupling slot 10.

[0043] The first microstrip feed line 13 is located on the lower surface of the second dielectric base layer; the second microstrip feed line 14 is located on the lower surface of the third dielectric base layer.

[0044] The first coupling slot 9 is coupled to the first microstrip feed line 13 to excite the first metallized through hole 5 and the first metal strip 4 and can generate an upward left-handed circularly polarized radiation wave.

[0045] The second coupling slot 10 is coupled to the second microstrip feed line 14 to excite the second metallized through-hole 6 and the second metal strip 7 and generate a right-handed circularly polarized radiation wave directed upward.

[0046] The first coupling slot 9 generates an electric field vector perpendicular to itself; the first plated via 5 and the first metal strip 4 as a whole generate an electric field vector parallel to itself. Similarly, the second coupling slot 10 generates an electric field vector perpendicular to itself; the second plated via 6 and the second metal strip 7 as a whole generate an electric field vector parallel to itself.

[0047] The present invention utilizes its inherent characteristics to achieve dual circular polarization, eliminating the need for additional phase difference in the feed network and resulting in a simple feed network structure. Dual circular polarization is achieved by forming the first coupling slot 9 and the first metallized vias 5 as a whole, which are equivalent to two mutually perpendicular magnetic dipoles; and by forming the second coupling slot 10 and the second metallized vias 6 as a whole, which are equivalent to two mutually perpendicular magnetic dipoles.

[0048] The first dielectric substrate 1 , the second dielectric substrate 2 , and the third dielectric substrate 3 are all parallel to the xoy plane of the spatial rectangular coordinate system o-xyz.

[0049] like Figure 4 As shown, the parameters of the first microstrip feed line 13 are K=5.59mm, Kg=1.2mm, Kd=2.18mm, d1=0.4mm, d2=0.11mm, d3=0.11mm, d4=1.21mm. The structural parameters of the first microstrip feed line 13 and the second microstrip feed line 14 are exactly the same. Figure 5 As shown, the relative positions of the first microstrip feed line 13 and the second microstrip feed line 14 are clearly shown.

[0050] Optionally, the first microstrip feed line 13 is provided with a first feeding port 11, and when the first feeding port 11 is feeding, the first microstrip feed line 13 is coupled with the first coupling slot 9; the second microstrip feed line 14 is provided with a second feeding port 12; when the second feeding port 12 is feeding, the second microstrip feed line 14 is coupled with the second coupling slot 10.

[0051] like Figure 7 As shown, the S11 and S22 parameters of the present invention are shown, that is, the input reflection coefficients of the first feeding port 11 and the second feeding port 12 , where S11 represents the input reflection coefficient of the first feeding port 11 and S22 represents the input reflection coefficient of the second feeding port 12 .

[0052] like Figure 8 As shown, the S21 parameter of the present invention, that is, the isolation parameter of the first feeding port 11 and the second feeding port 12, is shown; in the 28-38 GHz frequency band, the isolation of the antenna of the present invention is always better than -14.5 dB.

[0053] like Figure 9 As shown, when the first feeding port 11 is fed, the second feeding port 12 is not fed; similarly, when the second feeding port 12 is fed, the first feeding port 11 is not fed. When the first feeding port 11 is fed, the 3-dB axial ratio bandwidth covers the 27.5-38.0GHz frequency band, and the relative bandwidth is 32.1%. Since the antenna radiates left-handed circularly polarized waves when the first feeding port 11 is fed (port 2 is not fed at this time), the 3-dB axial ratio bandwidth is the circular polarization bandwidth of the antenna when radiating left-handed circularly polarized waves. As shown Figure 10 As shown in the figure, the radiation pattern of the antenna in the xoz plane at 32GHz, it can be seen that in the +z direction, the antenna radiates left-hand circularly polarized waves. Figure 11 As shown in Figure 1, the radiation pattern of the antenna in the yoz plane at a frequency of 32 GHz. It can be seen that in the +z direction, the antenna radiates left-handed circularly polarized waves.

[0054] like Figure 12 As shown in FIG. 1 , when the second feed port 12 is fed, the 3-dB axial ratio bandwidth covers the 28.1-37.4 GHz frequency band, and the relative bandwidth is 28.4%. Since the antenna radiates right-hand circularly polarized waves when the second feed port 12 is fed (the first feed port 11 is not fed at this time), the 3-dB axial ratio bandwidth is the circular polarization bandwidth of the antenna when radiating right-hand circularly polarized waves. Figure 13 As shown in the figure, the radiation pattern of the antenna in the xoz plane at 32GHz, it can be seen that in the +z direction, the antenna radiates right-hand circularly polarized waves. Figure 14 As shown in Figure 1, the radiation pattern of the antenna in the yoz plane at a frequency of 32 GHz. It can be seen that in the +z direction, the antenna radiates right-hand circularly polarized waves.

[0055] Optionally, the height of the first metallized through hole 5 is the same as the thickness of the first dielectric substrate 1 ; the height of the second metallized through hole 6 is the same as the thickness of the first dielectric substrate 1 .

[0056] like Figure 2 As shown, the first dielectric substrate 1 has a length L = 10 mm and a width W = 10 mm; the coupling slots have a length Ls = 7 mm and a width Ws = 0.4 mm. The length and width of the second dielectric substrate 2 and the length and width of the third dielectric substrate 3 are the same as those of the first dielectric substrate 1.

[0057] Optionally, the first dielectric substrate 1 , the second dielectric substrate 2 , and the third dielectric substrate 3 are all Rogers 5880 dielectric substrates.

[0058] Optionally, the dielectric constants of the first dielectric substrate 1 , the second dielectric substrate 2 , and the third dielectric substrate 3 are all 2.2, and the loss angles are all tanδ=0.0009.

[0059] like Figure 6 As shown, the antenna has a three-layer PCB structure. The thickness of the first dielectric substrate 1 is h1 = 1.575mm; the thickness of the second dielectric substrate 2 is h2 = 0.127mm; and the thickness of the third dielectric substrate 3 is h3 = 0.127mm. The PCB structure offers advantages such as a low profile, simple structure, ease of design optimization, and ease of fabrication, manufacturing, and integration.

[0060] Optionally, the first metal strip 4 is an I-shaped structure as a whole, the middle "vertical" part of the "I" shape is parallel to the first coupling gap 9, and is located in the middle position of the first dielectric substrate 1; the second metal strip 7 is an I-shaped structure as a whole, the middle "vertical" part of the "I" shape is parallel to the second coupling gap 10, and is located in the middle position of the first dielectric substrate 1.

[0061] like Figure 3 As shown, the parameters of the first metal strip 4 and the second metal strip 7 are exactly the same, and the length of the metal strip L1 = 4.8 mm; at the same time, L2 = 1.25 mm, L3 = 2.2 mm, Lg = 0.5 mm, Ld = 0.3 mm, R1 = 0.2 mm, and R2 = 0.2 mm.

[0062] Optionally, the lengths of the first metal strip 4 and the second metal strip 7 are both half the wavelength corresponding to the circular polarization center frequency.

[0063] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0064] The principles and implementation methods of the present invention are described herein using specific examples. Furthermore, those skilled in the art will appreciate that variations in the specific implementation methods and scope of application are possible based on the concepts of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A planar dual circularly polarized antenna based on orthogonal magnetic dipoles, characterized in that: The planar dual circular polarization antenna comprises: a first dielectric substrate, a second dielectric substrate, a third dielectric substrate, a metal layer, a first metal strip, a second metal strip, a first microstrip feed line and a second microstrip feed line; The first dielectric substrate, the metal layer, the second dielectric substrate and the third dielectric substrate are stacked from top to bottom; a first coupling slot and a second coupling slot are provided in the middle of the metal layer, intersecting at an angle of 90 degrees; The first metal strip and the second metal strip are located on the upper surface of the first dielectric substrate, and the first metal strip and the second metal strip overlap at the center portion of the first dielectric substrate; the first dielectric substrate is provided with two first metallized through-holes and two second metallized through-holes, the first metal strip is connected to the metal layer via the two first metallized through-holes, and the second metal strip is connected to the metal layer via the two second metallized through-holes; the two first metallized through-holes are closely adjacent to the edges of the first coupling slot, and the two first metallized through-holes are rotationally symmetric about the first coupling slot; the two second metallized through-holes are closely adjacent to the edges of the second coupling slot, and the two second metallized through-holes are rotationally symmetric about the second coupling slot; The first microstrip feed line is located on the lower surface of the second dielectric substrate; the second microstrip feed line is located on the lower surface of the third dielectric substrate; The first coupling slot is coupled to the first microstrip feed line, and is used to excite the first metallized through hole and the first metal strip, and is capable of generating an upward left-handed circularly polarized radiation wave; The second coupling slot is coupled to the second microstrip feed line, and is used to excite the second metallized through hole and the second metal strip, and can generate an upward right-handed circularly polarized radiation wave.

2. The planar dual circularly polarized antenna based on orthogonal magnetic dipoles according to claim 1, characterized in that: The first microstrip feed line is provided with a first feeding port, and when the first feeding port is feeding power, the first microstrip feed line is coupled with the first coupling slot; the second microstrip feed line is provided with a second feeding port; when the second feeding port is feeding power, the second microstrip feed line is coupled with the second coupling slot.

3. The planar dual circularly polarized antenna based on orthogonal magnetic dipoles according to claim 1, characterized in that: The antenna is a three-layer PCB structure.

4. The planar dual circularly polarized antenna based on orthogonal magnetic dipoles according to claim 1, characterized in that: The height of the first metallized through hole is the same as the thickness of the first dielectric substrate; the height of the second metallized through hole is the same as the thickness of the first dielectric substrate.

5. The planar dual circularly polarized antenna based on orthogonal magnetic dipoles according to claim 1, characterized in that: The first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all Rogers 5880 dielectric substrates.

6. The planar dual circularly polarized antenna based on orthogonal magnetic dipoles according to claim 1, characterized in that: The first metal strip has an overall I-shaped structure, with the middle vertical portion of the I-shaped structure being parallel to the first coupling slit and located in the middle of the first dielectric substrate. The second metal strip has an overall I-shaped structure, with the middle vertical portion of the I-shaped structure being parallel to the second coupling slit and located in the middle of the first dielectric substrate.

7. The planar dual circularly polarized antenna based on orthogonal magnetic dipoles according to claim 1, characterized in that: The dielectric constants of the first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are all 2.2, and the loss angles are all tanδ=0.0009.

8. The planar dual circularly polarized antenna based on orthogonal magnetic dipoles according to claim 1, characterized in that: The lengths of the first metal strip and the second metal strip are both half the wavelength corresponding to the circular polarization center frequency.

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