Broadband circularly polarized millimeter wave magnetoelectric dipole antenna

Abstract

The invention belongs to the technical field of antennas, and provides a broadband circularly polarized millimeter wave magnetoelectric dipole antenna which comprises an excitation port, a microstrip feeder line, a 0.127 mm thick dielectric plate, a bonding layer, a metal floor, a grounding copper column, a 1.575 mm thick dielectric plate, a radiation patch and a parasitic patch. According to the millimeter wave circularly polarized antenna disclosed by the invention, the circular arc-shaped patch and the rectangular patch are effectively overlapped, and the axial ratio bandwidths of the two antennas are combined, so that a new radiation patch is formed, the broadband is realized, the axial ratio of the designed antenna unit is increased from 29.72 GHz-33.19 GHz to 27.95 GHz-43.33 GHz on the premise that the existing radiation performance is not influenced, and the antenna unit has a wide application prospect. The frequency band range of the antenna impedance matching lower than-10dB is 23.8-61.6 GHz, and the impedance matching relative bandwidth reaches 88.5%; the range of the frequency band with the axial ratio lower than 3dB is 27.95-43.33 GHz, and the relative bandwidth of the axial ratio reaches 43.1%; the frequency band range of the 3dB gain is 25.09-42.09 GHz, the relative bandwidth of the 3dB gain reaches 50.6%, the maximum gain 9.6 dBic is achieved at the 34GHz, the performance is excellent in all aspects, and the requirement of a broadband wireless communication system can be met.

Description

Technical Field

[0001] The 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 bands have therefore been widely used. Circularly polarized antennas have excellent resistance to multipath effects and the ability to reduce polarization mismatch and have great application prospects. However, the current working bandwidth of general circularly polarized millimeter wave antennas is relatively narrow and it is difficult to meet the requirements of wireless communications; when the working bandwidth of the antenna is made wide enough, it will face the problem of too large a cross-section and is not easy to integrate; 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] At present, many of the disclosed circularly polarized millimeter wave antenna patents still have some problems in terms of working bandwidth, feeding network, gain, size, profile, etc. For example, the antenna using SIW (Substrate integrated waveguide) substrate integrated waveguide feeding has a higher gain, but this feeding method is more complicated and more difficult to process; patch antennas have the advantages of low profile and easy processing, but their current excitation mode is single, resulting in very limited bandwidth; antennas with wide axial ratio bandwidth have higher requirements for radiating patches, which must generate multiple resonance points and ensure that the patch structure will not cause a decrease in gain at a certain frequency point due to coupling problems. The following is an introduction to some of the disclosed patents: The invention patent application with Chinese patent publication number CN116073120A discloses a broadband millimeter-wave circularly polarized antenna unit, a single-mode array, and a dual-mode array. The antenna unit realizes circular polarization by placing two magnetic dipoles perpendicular to each other and giving a phase difference of 90°, and then expands the axial ratio bandwidth and gain of the antenna by adding parasitic patches. The S11 of the antenna unit is 25.4-40.2GHz (45.1%), the axial ratio bandwidth covers 29.3-37.0GHz (23.2%), and the gain bandwidth is about 29.1-34.9GHz (18.1%). The antenna realizes circular polarization in a novel way, but the axial ratio bandwidth and gain bandwidth of its unit are still narrow.

[0004] The invention patent application with the Chinese patent publication number CN114156643A discloses an ultra-wideband millimeter-wave planar spiral circularly polarized antenna array. The antenna excites a pair of spiral patches through a slot to radiate circularly polarized waves. The impedance bandwidth of the antenna is 25-42.26GHz (51.3%), the axial ratio bandwidth is 22.65-41.2GHz (58%), and the maximum gain is 7.9dBic. Although the antenna uses the characteristics of the spiral antenna to achieve a wide axial ratio bandwidth, the gain of the antenna is low.

[0005] The invention patent application with the Chinese patent publication number CN117578075A discloses a millimeter wave circularly polarized antenna based on orthogonal electric dipoles. The antenna generates circular polarization by exciting a pair of mutually perpendicular electric dipoles with a butterfly-shaped slot. The electric dipoles are located on the upper and lower sides of the plate to generate a 90° phase difference. The structure is simple and easy to process, but the working bandwidth of the antenna is only 5.1%.

[0006] The invention patent application with Chinese patent publication number CN116742329A discloses a circularly polarized millimeter wave antenna. The antenna uses a microstrip line to excite a trapezoidal patch through an "I"-shaped slot. The different side lengths of the patch cause the current to generate a perturbation to achieve circular polarization. However, the antenna does not do a good job of impedance matching, so its impedance bandwidth is only about 8%, which reduces the performance of the antenna.

[0007] The invention patent application with the Chinese patent publication number CN117996429A discloses a broadband millimeter-wave end-fire circularly polarized magneto-electric dipole antenna based on SIW. Based on the substrate integrated waveguide feeding structure, the antenna loads "U"-shaped grooves on the upper and lower surfaces of the metal to balance the magnetic dipole and the electric dipole, and increases the resonance point by adding the "butterfly-shaped radiation patch" structure to widen the axial ratio. The antenna has a simple structure and is easy to optimize performance. The S11 (<-10dB) bandwidth is 65.4%, the AR (<3dB) bandwidth is 36.1%, the overlap bandwidth is 36.1%, and the profile height is 0.26λg (λg is the center frequency 33GHz), but the gain flatness is not enough. Summary of the invention

[0008] In view of 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 structure and feeding method of the antenna simple enough.

[0009] To achieve the above object, the present invention adopts the following technical solutions: 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, 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 arranged in the center of the metal floor, and the radiation patch and the parasitic patch are arranged at 1.57 The upper surface of the 5mm thick dielectric plate, the grounding copper column penetrates the 1.575mm thick dielectric plate, and the two ends are respectively connected to the radiation patch and the metal floor, 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 patches and one rectangular patch, the arc patches are respectively located on the upper and lower sides of the rectangular slot, the two arc patches are connected by the rectangular patch to form a radiation patch, and there are two parasitic patches, which are symmetrical around the center point of the antenna.

[0010] Preferably, the radius of the arc-shaped patch is 2.5 mm, and the shape is a quarter of an arc.

[0011] 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 radiation patch is 29.63–41.68 GHz, and the relative bandwidth is 33%. Preferably, the microstrip feed line comprises 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.

[0012] Preferably, the parasitic patch is cut with four corners, namely, corner one, corner two, corner three and corner four, and the corner depths are 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.

[0013] Preferably, the microstrip feed line is located in the center of a rectangular slot of the metal floor.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 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), and combines the axial ratio bandwidths of the two antennas to form a new radiation patch, thereby achieving a wideband. Without affecting the existing radiation performance, the axial ratio of the designed antenna unit is increased from 29.72GHz-33.19GHz to 27.95GHz-43.33GHz, thereby greatly improving the performance of the antenna without affecting the antenna profile.

[0015] 2. The frequency range of the circularly polarized patch array antenna impedance matching below -10dB is 23.8-61.6GHz, and the impedance matching relative bandwidth reaches 88.5%; the frequency range of the axial ratio below 3dB is 27.95-43.33GHz, and the axial ratio relative bandwidth reaches 43.1%; the frequency range of 3dB gain is 25.09-42.09GHz, and the 3dB gain relative bandwidth reaches 50.6%, and the maximum gain of 9.6dBic is achieved at 34GHz. It has excellent performance in all aspects and can meet the requirements of broadband wireless communication systems.

[0016] 3. The antenna unit structure of the present invention is unified, and through reasonable layout, it can form a 2×2 or larger array to achieve higher gain and extended bandwidth. In addition, the antenna type is a patch, which is suitable for multi-layer printed circuit board (PCB) processing and is very easy to mass produce. Therefore, it has a good application prospect in broadband wireless communication systems.

[0017] 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 easy to integrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0019] Figure 2 It is a schematic diagram of the planar structure of the present invention.

[0020] Figure 3 It is a schematic diagram of the side structure of the present invention.

[0021] Figure 4 The following are the steps for designing the antenna of the present invention.

[0022] Figure 5 This is a comparison diagram of the axial ratio of the antenna of the present invention.

[0023] Figure 6 This is the impedance matching diagram of the antenna simulation of the present invention.

[0024] Figure 7 This is the simulated gain diagram of the antenna of the present invention.

[0025] Figure 8: is the radiation pattern of the XOZ plane of the antenna of the present invention at 30 GHz.

[0026] Fig. 9 : This is the radiation pattern of the YOZ plane of the antenna of the present invention at 34 GHz.

[0027] Fig.10 : is the radiation pattern of the XOZ plane of the antenna of the present invention at 38 GHz. DETAILED DESCRIPTION

[0028] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0029] like Figure 1 As shown, a broadband circularly polarized millimeter-wave magnetoelectric dipole antenna of the present invention comprises 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 column 402, a 1.575 mm thick dielectric plate 500, a radiation patch 601 and a parasitic patch 602. Four corners are cut on the parasitic patch 602, namely a cut corner 603, a cut corner 604 and two cut 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, the 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 the two ends are respectively connected to the radiation patch 601 and the metal floor 400, and the via 501 is under the dielectric plate 500.

[0030] 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 successfully 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.

[0031] There are two parasitic patches 602, symmetrical around the center point of the antenna. The angle depth of each parasitic patch is arranged from large to small as follows: angle 603 = angle 605 > angle 604. Angles 604 and 605 are mainly used to allow current to generate perturbations to expand the axial ratio bandwidth, and angle 603 is mainly used to adjust the impedance bandwidth.

[0032] 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.

[0033] The design process of the radiation patch 601 of the present invention is as follows: Figure 4 As shown, the radiation patch 601 is mainly composed of two antennas, namely antenna 1 and antenna 2. The 3-dB axial ratio bandwidth of antenna 1 is 29.7-33.72 GHz, and the relative bandwidth is 12.45%. The 3-dB axial ratio bandwidth of antenna 2 is 30.5-37.9 GHz, and the relative bandwidth is 21.5%. Antenna 3 (i.e., radiation patch 4) is obtained by cleverly superimposing and optimizing antenna 1 and antenna 2. The 3-dB axial ratio bandwidth of antenna 3 is 29.63–41.68 GHz, and the relative bandwidth is 33%, which is approximately the sum of the relative bandwidths of the first two. Finally, a pair of parasitic patches are added on the basis of antenna 3 to further expand the axial ratio bandwidth to obtain antenna 4.

[0034] 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 an arc, and only in this way can it be effectively superimposed with antenna 1.

[0035] 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 of 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%.

[0036] Unlike patent CN116073120A, the present invention changes the shape of the radiation patch 601 by effectively superimposing two antennas, increases the current path of the antenna, and thus expands the axial ratio bandwidth. The advantage is that the frequency band of the antenna of the present invention with an axial ratio lower than 3dB is 27.95-43.33GHz, and the relative bandwidth is 43.1%, while the frequency band of the antenna unit axial ratio lower than 3dB in patent CN116073120A is 29.3-37.0GHz, and the relative bandwidth is 23.2%. The axial ratio bandwidth of the antenna of the present invention is much wider. In addition, the antenna also uses a pressing process, which does not require the use of additional nylon columns to fix the dielectric plate 200 and the dielectric plate 500, reducing the volume of the antenna for easy integration.

[0037] 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 the bandwidth of the present invention reaches 50.6%, which is better than the former.

[0038] like Figure 6 and Figure 7 As shown, the frequency band of the antenna simulation impedance matching below -10dB is 23.8-61.6GHz, and the impedance matching relative bandwidth is 88.5%; the frequency band 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.

[0039] like Figure 8 , Fig. 9 and Fig.10 As shown, the XOZ plane radiation patterns of the millimeter-wave circularly polarized antenna at 30 GHz, 34 GHz and 38 GHz respectively, and it can be seen that the antenna has good right-hand polarization characteristics.

[0040] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. 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 in that: The invention 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, 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 arranged in the center of the metal floor, the radiation patch and the parasitic patch are arranged on the upper surface of the 1.575 mm thick dielectric plate, the grounding copper column penetrates the 1.575 mm thick dielectric plate, and the two ends are respectively connected to the radiation 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 radiation 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 radiation 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, characterized in that: The radius of the arc-shaped patch is 2.5 mm, and the shape is a quarter of an arc.

3. The broadband circularly polarized millimeter-wave magnetoelectric dipole antenna according to claim 2, characterized in that: 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 patch is 30.5-37.9 GHz, and the relative bandwidth is 21.5%. The 3-dB axial ratio bandwidth of the radiation 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, characterized in that: The microstrip feed line comprises 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, characterized in that: 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.

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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