Broadband circularly polarized millimeter-wave magnetoelectric dipole antenna

Abstract

The present invention belongs to the field of antenna technology and provides a broadband circularly polarized millimeter-wave magnetoelectric dipole antenna, comprising an excitation port, a microstrip feed line, a 0.127 mm thick dielectric plate, an adhesive layer, a metal floor, a grounding copper column, a 1.575 mm thick dielectric plate, a radiation patch, and a parasitic patch. The millimeter-wave circularly polarized antenna of the present invention effectively superimposes a circular arc patch and a rectangular patch, combining the axial ratio bandwidth of the two antennas to form a new radiation patch, thereby achieving a wide bandwidth. Without affecting the existing radiation performance, the axial ratio of the designed antenna unit is increased from 29.72GHz to 33.19GHz to 27.95GHz to 43.33GHz. The frequency band in which the antenna impedance matching is less than 10dB is 23.8-61.6GHz, and the impedance matching relative bandwidth reaches 88.5%; the frequency band in which the axial ratio is less than 3dB is 27.95-43.33GHz, and the axial ratio relative bandwidth reaches 43.1%; the frequency band in which the 3dB gain is 25.09-42.09GHz, and the 3dB gain relative bandwidth reaches 50.6%. The maximum gain of 9.6dBic is achieved at 34GHz, and the performance is excellent in all aspects, which can meet the requirements of broadband wireless communication systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and in particular relates to a broadband circularly polarized millimeter-wave magnetoelectric dipole antenna. Background Art

[0002] With the development of communication technology, spectrum resources are becoming increasingly scarce, and millimeter-wave frequency bands have therefore been widely used. Circularly polarized antennas have excellent anti-multipath effects and the ability to reduce polarization mismatch, and therefore have great application prospects. However, the current operating bandwidth of general circularly polarized millimeter-wave antennas is relatively narrow, which is difficult to meet the requirements of wireless communication. When the operating bandwidth of the antenna is made wide enough, it will face the problem of excessive cross-section and difficulty in integration. At the same time, the feeding method not only affects the performance of the antenna but also affects the difficulty of processing the actual object.

[0003] Currently, many patents for circularly polarized millimeter-wave antennas have some problems in terms of operating bandwidth, feeding network, gain, size, profile, and other aspects. For example, antennas using SIW (substrate integrated waveguide) substrate integrated waveguide feeding have higher gain, but this feeding method is relatively complex and difficult to process. Patch antennas have advantages such as low profile and easy processing, but their single current excitation mode leads to very limited bandwidth. Antennas with wide axial ratio bandwidth have relatively high requirements for radiating patches, which must generate multiple resonant points while ensuring that the patch structures do not cause gain reduction at certain frequencies due to coupling problems. The following is an introduction to some of the published patents:

[0004] The invention patent application with Chinese patent publication number CN116073120A discloses a broadband millimeter-wave circularly polarized antenna unit, single-mode array, and dual-mode array. This antenna unit achieves circular polarization by placing two magnetic dipoles perpendicular to each other and giving them a 90° phase difference. The antenna's axial ratio bandwidth and gain are expanded by adding parasitic patches. The antenna unit has an S11 of 25.4-40.2 GHz (45.1%), an axial ratio bandwidth covering 29.3-37.0 GHz (23.2%), and a gain bandwidth of approximately 29.1-34.9 GHz (18.1%). This antenna achieves circular polarization in a novel manner, but the unit's axial ratio bandwidth and gain bandwidth are still relatively narrow.

[0005] Chinese patent application CN114156643A discloses an ultra-wideband millimeter-wave planar spiral circularly polarized antenna array. This antenna excites a pair of spiral patches through a slot, causing them to radiate circularly polarized waves. The antenna has an impedance bandwidth of 25-42.26 GHz (51.3%), an axial ratio bandwidth of 22.65-41.2 GHz (58%), and a maximum gain of 7.9 dBic. While this antenna leverages the characteristics of spiral antennas to achieve a wide axial ratio bandwidth, its gain is relatively low.

[0006] Chinese patent application CN117578075A discloses a millimeter-wave circularly polarized antenna based on orthogonal electric dipoles. This antenna generates circular polarization by exciting a pair of mutually perpendicular electric dipoles through a butterfly-shaped slot. The dipoles are located on the upper and lower sides of the plate, creating a 90° phase difference. While its structure is simple and easy to manufacture, the antenna's operating bandwidth is limited to 5.1%.

[0007] Chinese patent application CN116742329A discloses a circularly polarized millimeter-wave antenna. This antenna uses a microstrip line through an I-shaped slot to excite a trapezoidal patch. The varying side lengths of the patch cause current perturbations, thus achieving circular polarization. However, the antenna lacks proper impedance matching, resulting in an impedance bandwidth of only approximately 8%, reducing its performance.

[0008] Chinese patent application CN117996429A discloses a broadband millimeter-wave end-fire circularly polarized magnetoelectric dipole antenna based on a SIW. Based on a substrate-integrated waveguide feed structure, this antenna incorporates U-shaped metal slots on the upper and lower surfaces to balance the magnetic and electric dipoles. The antenna also incorporates a "butterfly-shaped radiating patch" to increase the resonance points and broaden the axial ratio. The antenna has a simple structure and is easy to optimize. Its S11 (<-10dB) bandwidth is 65.4%, its AR (<3dB) bandwidth is 36.1%, its overlap bandwidth is 36.1%, and its profile height is 0.26λg (λg is the center frequency of 33GHz). However, its gain flatness is insufficient. Summary of the Invention

[0009] In response to the problems in the background technology, the present invention develops a broadband circularly polarized millimeter-wave magnetoelectric dipole antenna, which expands the working bandwidth of the antenna by introducing two new currents and parasitic patches while keeping the antenna structure and feeding method simple enough.

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] A broadband circularly polarized millimeter-wave magnetoelectric dipole antenna comprises an excitation port, a microstrip feeder, a 0.127 mm thick dielectric plate, an adhesive layer, a metal floor, a grounding copper column, a 1.575 mm thick dielectric plate, a radiation patch, and a parasitic patch. The excitation port is connected to the microstrip feeder, which is arranged on the lower surface of the 0.127 mm thick dielectric plate. The metal floor is arranged on the lower surface of the 1.575 mm thick dielectric plate. A rectangular slot is provided in the center of the metal floor. The radiation patch and the parasitic patch are arranged on the 1.57 The upper surface of the 5mm thick dielectric plate, the grounding copper column passes through the 1.575mm thick dielectric plate, and the two ends are respectively connected to the radiation patch and the metal floor, and the adhesive layer is used to bond the 0.127mm thick dielectric plate and the 1.575mm thick dielectric plate; the radiation patch includes two arc-shaped patches and one rectangular patch, and the arc-shaped patches are respectively located on the upper and lower sides of the rectangular slot. The two arc-shaped patches are connected by a rectangular patch to form a radiation patch. There are two parasitic patches, which are symmetrical around the center point of the antenna.

[0012] Preferably, the radius of the arc-shaped patch is 2.5 mm, and the shape is a quarter of a circle.

[0013] Preferably, the 3-dB axial ratio bandwidth of the rectangular patch is 29.7-33.72 GHz, and the relative bandwidth is 12.45%. The 3-dB axial ratio bandwidth of the arc-shaped patch is 30.5-37.9 GHz, and the relative bandwidth is 21.5%. The 3-dB axial ratio bandwidth of the radiating patch is 29.63–41.68 GHz, and the relative bandwidth is 33%.

[0014] Preferably, the microstrip feed line includes a first section microstrip line, a cut corner, and a second section microstrip line connected in sequence, and the first section microstrip line is perpendicular to the first section microstrip line.

[0015] Preferably, the parasitic patch is cut with four corners, namely, corner one, corner two, corner three and corner four, and the depth of the corners is arranged from large to small as follows: corner one = corner three = corner four > corner two. Corner two, corner three and corner four are mainly used to allow the current to generate perturbations to expand the axial ratio bandwidth, and corner one is mainly used to adjust the impedance bandwidth.

[0016] Preferably, the microstrip feed line is located in the center of a rectangular slot in the metal floor.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The millimeter-wave circularly polarized antenna of the present invention effectively superimposes a rectangular patch (antenna 1) and an arc-shaped patch (antenna 2), combining the axial ratio bandwidths of the two antennas to form a new radiating patch, achieving a wideband. Without affecting the existing radiation performance, the axial ratio of the designed antenna unit is increased from 29.72 GHz to 33.19 GHz to 27.95 GHz to 43.33 GHz, greatly improving the antenna performance without affecting the antenna cross-section.

[0019] 2. The circularly polarized patch array antenna of the present invention has an impedance matching frequency range of less than -10dB of 23.8-61.6GHz, and an impedance matching relative bandwidth of 88.5%; an axial ratio of less than 3dB of 27.95-43.33GHz, and an axial ratio relative bandwidth of 43.1%; a 3dB gain frequency range of 25.09-42.09GHz, and a 3dB gain relative bandwidth of 50.6%, reaching a maximum gain of 9.6dBic at 34GHz. It has excellent performance in all aspects and can meet the requirements of broadband wireless communication systems.

[0020] 3. The antenna units of the present invention have a unified structure and can be arranged into a 2×2 or larger array through reasonable layout, achieving higher gain and extended bandwidth. In addition, the antenna type is a patch, suitable for multi-layer printed circuit board (PCB) processing and very easy to mass-produce. Therefore, it has good application prospects in broadband wireless communication systems.

[0021] 4. The millimeter-wave circularly polarized antenna unit of the present invention is based on microstrip line feeding, and the feeding method is simple and conducive to integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0023] Figure 2 It is a schematic diagram of the planar structure of the present invention.

[0024] Figure 3 It is a side structural schematic diagram of the present invention.

[0025] Figure 4 This is the antenna design step of the present invention.

[0026] Figure 5 This is a comparison diagram of the axial ratio of the antenna of the present invention.

[0027] Figure 6 This is the impedance matching diagram of the antenna simulation of the present invention.

[0028] Figure 7 This is the simulated gain diagram of the antenna of the present invention.

[0029] Figure 8: This is the radiation pattern of the XOZ plane of the antenna of the present invention at 30 GHz.

[0030] Figure 9 : This is the radiation pattern of the antenna of the present invention on the YOZ plane at 34 GHz.

[0031] Figure 10 : This is the radiation pattern of the XOZ plane of the antenna of the present invention at 38 GHz. DETAILED DESCRIPTION

[0032] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0033] like Figure 1 As shown, a broadband circularly polarized millimeter-wave magnetoelectric dipole antenna according to the present invention includes an excitation port 100, a microstrip feed line 101, a 0.127 mm thick dielectric plate 200, an adhesive layer 300, a metal floor 400, a rectangular slot 401 in the center of the floor, a grounding copper post 402, a 1.575 mm thick dielectric plate 500, a radiating patch 601, and a parasitic patch 602. Parasitic patch 602 has four corners cut off: corner 603, corner 604, and two corners 605. The microstrip feed line 101 is printed on the lower surface of the dielectric plate 200, the excitation port 100 is connected to the microstrip feed line 101, the adhesive layer 300 is used to bond the dielectric plate 200 and the dielectric plate 500, the metal floor 400 is set on the lower surface of the dielectric plate 500 by printing, and a rectangular slot 401 is etched in the center of the metal floor 400. The radiation patch 601 and the parasitic patch 602 are printed on the upper surface of the dielectric plate 500. The grounding copper column 402 passes through the dielectric plate 500, and its two ends are respectively connected to the radiation patch 601 and the metal floor 400, and a via 501 is provided under the dielectric plate 500.

[0034] like Figure 2 As shown, the antenna is fed through the excitation port 100, and the energy is transmitted to the first section of the microstrip line 1011. The impedance bandwidth of the antenna is adjusted by adjusting the cut angle 1012 of the microstrip feed line 101 and the width of the second section of the microstrip line 1013 so that the rectangular slot 401 can be smoothly excited. A portion of the energy on the rectangular slot 401 is conducted to the radiation patch 601 through the grounding copper column 402. The arc structure 600 on the radiation patch 601 provides an additional current path to improve the axial ratio bandwidth of the antenna. The parasitic patch 602 is excited in a coupled manner to further improve the performance of the antenna.

[0035] There are two parasitic patches 602, symmetrically arranged around the antenna's center point. The depth of the chamfers on each parasitic patch is arranged in descending order: chamfer 603 = chamfer 605 > chamfer 604. Chamfers 604 and 605 are primarily used to perturb the current and expand the axial ratio bandwidth, while chamfer 603 is primarily used to adjust the impedance bandwidth.

[0036] like Figure 3 As shown, the microstrip feed line 101 on the lower surface of the dielectric plate 200 excites the rectangular slot 401 printed in the metal floor 400 on the lower surface of the dielectric plate 500, and the grounding copper column 402 conducts the energy obtained from the metal floor 400 to the radiation patch 601 on the upper surface of the dielectric plate 500. The dielectric plate 500 and the dielectric plate 200 are connected by the adhesive layer 300.

[0037] The design process of the radiation patch 601 of the present invention is as follows Figure 4 As shown, radiating patch 601 is primarily composed of two antennas: Antenna 1 and Antenna 2. Antenna 1 has a 3-dB axial bandwidth of 29.7–33.72 GHz, with a relative bandwidth of 12.45%. Antenna 2 has a 3-dB axial bandwidth of 30.5–37.9 GHz, with a relative bandwidth of 21.5%. Antenna 3 (i.e., radiating patch 4) is obtained by cleverly superimposing and optimizing Antennas 1 and 2. Antenna 3 has a 3-dB axial bandwidth of 29.63–41.68 GHz, with a relative bandwidth of 33%, roughly the sum of the relative bandwidths of the previous two antennas. Finally, a pair of parasitic patches is added to Antenna 3 to further expand the axial bandwidth, resulting in Antenna 4.

[0038] Antenna 3 is a quasi-helical antenna that can radiate circularly polarized waves. It can effectively radiate circularly polarized waves only when the radius Larm of the arc structure 600 is 2.5 mm and the shape is a quarter of a circle. Only in this way can it be effectively superimposed with antenna 1.

[0039] like Figure 5 As shown, it is a comparison curve of the simulation results of the millimeter-wave circularly polarized antenna, which shows that the performance of the antenna is getting better with each improvement. The frequency band in which the axial ratio of the present invention is lower than 3dB is 27.95-43.33GHz, and the relative bandwidth of the axial ratio is 43.1%.

[0040] Unlike patent CN116073120A, the present invention effectively superimposes two antennas, changes the shape of radiating patch 601, and increases the antenna's current path, thereby expanding the axial ratio bandwidth. The advantage is that the frequency band in which the axial ratio of the antenna of the present invention is less than 3dB is 27.95-43.33GHz, with a relative bandwidth of 43.1%. In contrast, the frequency band in which the antenna unit axial ratio is less than 3dB in patent CN116073120A is 29.3-37.0GHz, with a relative bandwidth of 23.2%. The axial ratio bandwidth of the antenna of the present invention is much wider. Furthermore, the present antenna uses a pressing process, eliminating the need for additional nylon posts to secure dielectric plates 200 and 500, reducing the antenna's size and facilitating integration.

[0041] Different from the patent CN114156643A, the maximum gain of the unit proposed in the patent CN114156643A is 7.9dBic, while the maximum gain of the present invention is 9.6dBic, and the gain relative to bandwidth of the present invention reaches 50.6%, which is better than the former.

[0042] like Figure 6 and Figure 7 As shown in the figure, the frequency range of the antenna simulation impedance matching below -10dB is 23.8-61.6GHz, and the impedance matching relative bandwidth is 88.5%; the frequency range of 3dB gain is 25.09-42.09GHz, and the gain relative bandwidth reaches 50.6%, and the maximum gain of 9.6dBic is achieved at 34.5GHz.

[0043] like Figure 8 、 Figure 9 and Figure 10 As shown in FIG, are the XOZ plane radiation patterns of the millimeter-wave circularly polarized antenna at 30 GHz, 34 GHz, and 38 GHz, respectively. It can be seen that the antenna has good right-hand polarization characteristics.

[0044] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical contents disclosed above. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. Broadband circularly polarized millimeter-wave magnetoelectric dipole antenna, characterized by: The antenna comprises an excitation port, a microstrip feeder, a 0.127 mm thick dielectric plate, an adhesive layer, a metal floor, a grounding copper column, a 1.575 mm thick dielectric plate, a radiating patch and a parasitic patch; the excitation port is connected to the microstrip feeder, the microstrip feeder is arranged on the lower surface of the 0.127 mm thick dielectric plate, the metal floor is arranged on the lower surface of the 1.575 mm thick dielectric plate, a rectangular slot is provided in the center of the metal floor, the radiating patch and the parasitic patch are arranged on the upper surface of the 1.575 mm thick dielectric plate, the grounding copper column passes through the 1.575 mm thick dielectric plate, and the two ends are respectively connected to the radiating patch and the metal floor, the adhesive layer is used to bond the 0.127 mm thick dielectric plate and the 1.575 mm thick dielectric plate; the radiating patch comprises two arc-shaped patches and one rectangular patch, the arc-shaped patches are respectively located on the upper and lower sides of the rectangular slot, the two arc-shaped patches are connected by a rectangular patch to form a radiating patch, and there are two parasitic patches, which are symmetrical around the center point of the antenna.

2. The broadband circularly polarized millimeter-wave magnetoelectric dipole antenna according to claim 1, wherein: The radius of the arc-shaped patch is 2.5 mm, and the shape is a quarter of a circle.

3. The broadband circularly polarized millimeter-wave magnetoelectric dipole antenna according to claim 2, wherein: The 3-dB axial ratio bandwidth of the rectangular patch is 29.7-33.72 GHz, and the relative bandwidth is 12.45%. The 3-dB axial ratio bandwidth of the arc-shaped patch is 30.5-37.9 GHz, and the relative bandwidth is 21.5%. The 3-dB axial ratio bandwidth of the radiating patch is 29.63–41.68 GHz, and the relative bandwidth is 33%.

4. The broadband circularly polarized millimeter-wave magnetoelectric dipole antenna according to claim 1, wherein: The microstrip feeder includes a first section microstrip line, a cut corner, and a second section microstrip line connected in sequence, and the first section microstrip line is perpendicular to the second section microstrip line.

5. The broadband circularly polarized millimeter-wave magnetoelectric dipole antenna according to claim 1, wherein: The parasitic patch is cut with four corners, namely corner one, corner two, corner three and corner four. The depth of the corners is arranged from large to small as follows: corner one = corner three = corner four > corner two. Corner two, corner three and corner four are mainly used to allow the current to generate perturbations to expand the axial ratio bandwidth, and corner one is mainly used to adjust the impedance bandwidth.

6. The broadband circularly polarized millimeter-wave magnetoelectric dipole antenna according to claim 1 or 4, characterized in that: The microstrip feed line is located in the center of the rectangular slot of the metal floor.

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