CN116315694A - Planar integrated circularly polarized magnetic dipole antenna with toothed openings - Google Patents

Abstract

The invention discloses a tooth-shaped opening plane integrated circularly polarized magnetoelectric dipole antenna based on a printed circuit board process, which belongs to the field of microwave antennas. The circularly polarized magnetoelectric dipole antenna of the present invention includes a first dielectric substrate 1, a metal floor 2, a lower second dielectric substrate 3, and a metallized through hole with the same size and closely attached to each other. The first dielectric substrate Two rotationally symmetrical metal patches 5 with tooth-shaped openings are arranged in the center of the upper surface, and the metal patches are treated with chamfering and tooth-shaped openings 7; the two rows of metallized through holes are arranged in the first medium In the substrate, the metal patch is connected to the metal floor; the upper surface of the second dielectric substrate is a metal bottom plate with a gap 8, and the lower surface of the dielectric substrate is a rectangular microstrip line 9 as a feed structure, which has a simple structure and The electrical size is smaller, and the planar integrated structure is easier to process and form an array.

Description

A Planar Integrated Circularly Polarized Magnetoelectric Dipole Antenna with Teeth Openings

technical field

The invention belongs to the technical field of microwave antennas, in particular to a planar integrated circularly polarized magnetoelectric dipole antenna with tooth-shaped openings.

Background technique

With the continuous development of modern wireless communication systems, it is necessary to achieve more stable communication in complex environments and conditions. Circularly polarized antennas have significant advantages such as strong anti-polarization interference ability, strong anti-multipath fading ability, and strong penetration ability, and are widely used in radar, satellite communication, global positioning system and other fields. In 2006, Professor Kwai-Man Luk proposed the magnetoelectric dipole antenna based on the principle of complementarity, which has the advantages of inherent broadband, stable and symmetrical pattern, low backlobe radiation and low cross polarization, making it a popular choice for many wireless antennas. The best choice for communication system antennas.

Compared with other antennas, the magnetoelectric dipole antenna has the outstanding advantages of high gain, broadband and stable radiation pattern. Therefore, the circularly polarized magnetoelectric dipole antenna came into being, which mainly generates two orthogonal and equal amplitude radiation electric fields with a 90° phase difference by making the magnetic dipole and the electric dipole of the magnetoelectric dipole to form circular polarization.

In recent years, scholars at home and abroad have conducted research on the application of circularly polarized magnetoelectric dipole antennas. In 2019, J.Sun et al published a paper entitled "WidebandLinearly-Polarized and Circularly-Polarized Aperture-Coupled Magneto-ElectricDipole Antennas Fed by Microstrip Line" on IEEE Access (vol.7, pp.43084-91, March.2019) With Electromagnetic Bandgap Surface", circularly polarized radiation is realized by combining two pairs of all-metal wire-polarized magnetoelectric dipoles and adding branches. The bandwidth of the antenna is 58% (3.44-6.27GHZ), and the bandwidth of Axial Ratio less than 3dB is 22.5% (3.75-4.7GHz). Moreover, the author can effectively suppress the backward radiation by adding the EBG structure at the bottom layer of the antenna.

In 2020, YFWang et al published an article entitled "Wideband Circularly Polarized Magneto-Electric Dipole 1×2 Antenna Array for Millimeter-Wave Applications" on IEEE Access (vol.8, pp.27516-27523, February.2020), The author achieves circular polarization by cutting the electric dipole part of the magnetoelectric dipole and adding branches, and the circular polarization bandwidth is only 9.7% (27.4-30.20). In order to expand the axial ratio bandwidth, the author formed a 1×2 antenna array, and designed a 1-to-2 power divider with a 90° phase difference based on the substrate integrated waveguide (SIW) as the feed network. The measurement results show that the axial ratio bandwidth is 24.7%, the highest in-band gain is 10dBic, which is 2.4 times higher than the 3dB AR bandwidth of a single antenna unit. However, the antenna size at this time is 3.5λ ₀ ×3.5λ ₀ ×0.14λ ₀ (λ ₀ is the wavelength corresponding to the center frequency of the antenna array), so the number of antennas that can be placed in a certain space is limited.

In 2021, LQWang et al published a paper entitled "Design of a Ka-Band Low-Profile Wideband Circularly Polarized Magneto-Electric Dipole Antenna With Parasitic Patches and Its Array" This antenna element replaces the rectangular electric dipole of a linearly polarized magnetoelectric dipole antenna with two inverted L metal strips to produce circularly polarized radiation. At the same time, four parasitic patches are added around the electric dipole to optimize the distribution of the orthogonal field in the far zone to achieve a low profile and expand the circular polarization bandwidth. Finally, the antenna profile is greatly reduced from the traditional 0.25λ ₀ to 0.1λ ₀ , and the overlapping bandwidth of impedance bandwidth and circular polarization bandwidth can reach 19.8%. However, the addition of parasitic structures not only complicates the structure of the antenna, but also increases its size to 1λ ₀ ×1λ ₀ ×0.1λ ₀ , which is severely limited for applications with limited space.

Therefore, since the antenna was proposed, it has received extensive attention from scholars at home and abroad, and on the basis of this antenna, researchers have proposed different frequency bands and various styles of antenna design schemes, which have very large applications in many fields. Potential, has a certain research value.

Contents of the invention

The object of the present invention is to provide a planar integrated circularly polarized magnetoelectric dipole antenna with tooth-shaped openings by using the basic principle of the magnetoelectric dipole. The antenna of the present invention realizes circular polarization mainly through the novel tooth-shaped opening structure, and the overall size of the antenna is small, and the planar integrated structure is also convenient for the application of the array.

The technical problem proposed by the present invention is solved like this:

A planar integrated circularly polarized magnetoelectric dipole antenna with tooth-shaped openings, comprising a first dielectric plate, a metal floor and a second dielectric substrate with the same size and closely fitted from top to bottom;

The center of the upper surface of the first dielectric substrate is provided with a pair of rotationally symmetrical metal patches with tooth-shaped openings, and a certain distance is reserved between them, and the metal patches are processed by adding branches and cutting corners; the first dielectric substrate A total of 10 metallized through holes are provided in two rows, the two rows of metal through holes are rotationally symmetrical, and the center of symmetry is the exact center of the dielectric substrate. Metallized vias run through the tooth-shaped opening metal patch and the metal floor, and connect the two. In order to make the metal vias well connect the tooth-shaped opening metal patches and the metal floor, the distance between two rows of metal vias is slightly larger than the distance between two metal patches. A rectangular gap is etched in the center of the metal floor, and two metal patches are located directly above the gap. The edges of the two metal patches cover the gap, so that the width of the gap is greater than the distance between the two metal patches, so as to enhance the coupling between the electromagnetic wave energy passing through the gap and the two metal patches.

By making tooth-shaped openings and chamfering on a pair of metal patches with tooth-shaped openings on the upper surface of the first dielectric plate, the phase and direction of current flow on them can be effectively changed, and the circularly polarized radiation performance of the antenna can be optimized.

There is a gap etched in the center of the metal floor, which is parallel to the long side of the tooth-shaped opening metal patch, and its center point coincides with the rotation center of the two tooth-shaped opening metal patches. The coupling between the pieces, the width of the gap is greater than the spacing between the two tooth-shaped opening metal patches 6.

The lower surface of the second dielectric substrate is provided with a microstrip feed structure. The microstrip feed structure is a microstrip line with an impedance of 50 ohms, located in the center of the dielectric substrate, and extending from the edge of the dielectric substrate to the gap of the metal floor. Directly below, and slightly beyond the gap, a part continues to extend.

A rectangular slit is etched in the metal floor, through which the energy of the microstrip line can be coupled to the metal via hole in the first dielectric plate and the tooth-shaped opening metal patch on the upper layer to excite circularly polarized radiation waves.

The antenna ports all adopt the microstrip feeding mode, and the input impedance of the ports is 50 ohms.

The beneficial effects of the present invention are:

(1) The present invention is based on the basic principle of the magnetoelectric dipole, utilizes two rows of metal through-holes to simulate the hammer metal wall of the all-metal magnetoelectric dipole in the first dielectric plate 1, so that the equivalent magnetic current can be in the two rows energized through metal vias. By modifying the shape of the metal patch 5 with two teeth-shaped openings, the current distribution on it is optimized, so that the current and the equivalent magnetic current can work together to generate two equal-amplitude orthogonal electric fields with a phase difference of 90° to realize circularly polarized radiation.

(2) A pair of metal patches with tooth-shaped openings on the upper surface of the first dielectric plate 1 of the present invention are treated with tooth-shaped openings, which can effectively change the phase of current flow on them and optimize the circular polarization radiation performance of the antenna. Adding stubs to a pair of metal patches with tooth-shaped openings on the upper surface of the first dielectric board 1 can adjust the first resonant frequency point of the antenna and optimize the matching of the antenna. Moreover, by adjusting the branch length of the tooth-shaped opening metal patch 5 , the flow direction of the current on it can be adjusted, so that the overall flow direction of the current is parallel to the long side of the tooth-shaped opening metal patch.

(3) The present invention changes the feeding structure of the magnetoelectric dipole 'I type to microstrip line coupling feeding, and this feeding method is convenient for the processing, integration and formation of the antenna.

(4) The circularly polarized magnetoelectric dipole with tooth-shaped openings in the present invention has a wider bandwidth, a smaller size, and a planar integrated structure, which is convenient for forming a circularly polarized antenna array.

Description of drawings

FIG. 1 is a schematic structural view of a circularly polarized magnetoelectric dipole antenna with toothed openings according to an embodiment of the present invention;

Fig. 2 is a side view of the antenna in Fig. 1;

Fig. 3 is a top view of the upper surface metal layer and metallized through holes of the upper first dielectric substrate in Fig. 2;

Fig. 4 is a top view of the middle metal layer in Fig. 2;

5 is a top view of the metal layer on the lower surface of the lower second dielectric substrate in FIG. 2;

Fig. 6 is a schematic diagram of S parameters and gain of the antenna described in the embodiment;

Fig. 7 is a schematic diagram of the axial ratio of the antenna described in the embodiment;

Fig. 8 is a distribution diagram of metal surface current and slot electric field when the antenna described in the embodiment works at 6.74 GHz;

Fig. 9 is a far-field radiation pattern when the antenna described in the embodiment works at 6.74 GHz.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

This embodiment provides a planar integrated circularly polarized magnetoelectric dipole antenna with a tooth-shaped opening. Combined first dielectric substrate 1, metal floor 2 and second dielectric substrate 3. The first dielectric substrate 1 is provided with two rows of metallized through-holes 4, a total of 10, the two rows of metallized through-holes are rotationally symmetrical, and the center of symmetry is the exact center of the dielectric substrate, and the metallized through-holes pass through the tooth-shaped opening metal patches 5 and Metal floor 2, and connect the two. In order to make the metal vias well connect the toothed opening metal patch 5 and the metal floor 2 , the distance between two rows of metal vias is slightly larger than the distance 6 between the metal patches. The top view of the metal layer and the metal through hole on the upper surface of the first dielectric substrate 1 is shown in Figure 3. A pair of rotationally symmetrical metal patches 5 with tooth-shaped openings are arranged at the center of the upper surface as the radiation structure of the antenna; the two metal patches There is a certain distance 6 between them, and the metal patch is treated with tooth-shaped openings, increased branches and corner cutting 7. The top view of the metal floor 2 is shown in Figure 4, a rectangular slit 8 is etched in its center, parallel to the long side 10 of the tooth-shaped opening metal patch, and its center point coincides with the rotation center of the two tooth-shaped opening metal patches . The long sides 10 of the two metal patches cover the gap 8, so that the width of the gap 8 is greater than the distance 6 between the two metal patches, so as to enhance the coupling between the electromagnetic wave energy passing through the gap and the two metal patches. The top view of the metal layer on the lower surface of the second dielectric substrate 3 is shown in Figure 5, the lower surface is provided with a microstrip feed structure, the microstrip feed structure is a microstrip line 9 with an impedance of 50 ohms, located in the center of the dielectric substrate , extends from the edge of the dielectric substrate to directly below the gap 8 of the metal floor 2, and continues to extend a part beyond the gap.

The material of the first dielectric substrate 1 is Rogers RO3203, the relative permittivity is 3.03, the loss tangent angle is 0.0016, and the thickness is 5.5mm; the material of the second dielectric substrate 2 is Rogers RT5880, the relative permittivity is 2.2, the loss tangent angle is 0.0009, and the thickness is The size of the dielectric substrate is 0.5mm; the size of the dielectric substrate is the same, both are 36mm×36mm; the size of 5 of the rectangular metal patch is 12.5mm×5.55mm, and there are 4 tooth-shaped openings in total, the depth is 1.2mm, and the width is 1mm; The pitch of the patch is 2mm. There are 10 metal through holes in the first dielectric substrate 1 in total, the radius of the through holes is 0.5 mm, and the distance between adjacent through holes is 0.425 mm. The rectangular gap on the metal floor 2 has a length of 10 mm and a width of 2.9 mm. In the microstrip feeding structure, the terminal open circuit is a microstrip line with a width of 2.4mm and a length of 22mm.

The size of the antenna described in this embodiment is 0.78λ ₀ ×0.78λ ₀ ×0.13λ ₀ (λ ₀ is the wavelength corresponding to the center frequency of the antenna operating frequency band), and its S parameter simulation results and gain diagram are shown in Figure 6, with Two resonant frequency points f _l and f _h have an operating frequency band of 5.65-7.38 GHz (relative bandwidth of 26.6%), and the average in-band gain of the antenna is 7.12 dBi. The frequency range where the axial ratio is less than 3dB is 6.53-7.22GHz (10%), and the schematic diagram of the axial ratio of the antenna is shown in FIG. 7 .

The circularly polarized magnetoelectric dipole designed in this embodiment produces circularly polarized radiation through the joint action of magnetic current and electric current. In this structure, the electromagnetic wave energy is coupled to the metal patch 5 above through the gap of the metal floor, and a current is formed on it to radiate electromagnetic waves outward; since two rows of closely arranged metal through holes can be regarded as two metal walls, a part of the electromagnetic energy Instead of acting on it, an equivalent magnetic current is formed in it. Figure 8 shows the current distribution on the patch surface and the electric field distribution at the gap when the designed antenna works at 6.74GHz. It can be seen that when t=T/4 and t=3T/4, the two rows of metallized vias connected to the metal patch are excited, and the electric field intensity at the gap is the largest, which is equivalent to generating Magnetic current in the -y direction. At the two moments of t=0 and t=T/2, the electric dipole is excited, and the surface current of the patch is mainly along the +y and -y directions. It can be known that within a period, the current and the equivalent magnetic current work alternately along the same direction, with a phase difference of 90°, thereby generating circularly polarized radiation waves.

The radiation pattern of the antenna at 6.74GHz is shown in Figure 9. The antenna unit maintains good side-firing characteristics in the entire frequency band, and the cross-polarization discrimination rate (XPD) in the z-axis direction is greater than 20dB, which has good polarization characteristics.

The magnetoelectric dipole antenna described in this embodiment adopts a novel tooth-shaped opening structure to realize circular polarization, and the feeding structure of the existing magnetoelectric dipole antenna 'I type is changed to microstrip line coupling feeding , this feeding method facilitates the processing, integration and formation of the antenna.

Finally, the circularly polarized magnetoelectric dipole has a wide bandwidth, a small size, and a planar integrated structure, which facilitates the formation of a circularly polarized antenna array.

Claims (6)

1. A planar integrated circularly polarized magnetoelectric dipole antenna of a toothed opening, characterized in that it comprises a first dielectric plate (1), a metal floor (2) and The second dielectric substrate (3); The center of the upper surface of the first dielectric substrate (1) is provided with a pair of rotationally symmetrical tooth-shaped opening metal patches (5), and a certain distance (6) is reserved between the two tooth-shaped opening metal patches (5). The opening metal patch (5) has increased branch and corner cutting treatment (7); the first dielectric substrate (1) is provided with two rows of metallization with rotational symmetry and the center of symmetry is the exact center of the first dielectric substrate (1) There are 10 through holes (4) in total, and the metallized through holes (4) run through the tooth-shaped opening metal patch (5) and the metal floor (2), and connect the two; two rows of metallized through holes (4) The distance between them is greater than the distance (6) between the metal patches (5) of the two tooth-shaped openings; the center of the metal floor (2) is etched with a horizontally arranged gap (8), and the gap (8) is located between the two tooth-shaped The opening metal patch (5) is directly below and parallel to the long sides (10) of the two tooth-shaped opening metal patches (5), and the width of the gap (8) is greater than the gap between the two tooth-shaped opening metal patches (5). spacing(6); The lower surface of the second dielectric substrate (3) is provided with a microstrip feed structure, the microstrip feed structure is a microstrip line (9) with an impedance of 50 ohms, and the microstrip line (9) is connected from the second dielectric substrate (3) The edge of the metal floor (2) extends vertically and beyond the gap (8) directly below the metal floor (2). 2 . The planar integrated circularly polarized magnetoelectric dipole antenna with toothed openings according to claim 1 , characterized in that the toothed opening metal patch ( 5 ) has toothed openings. 3 . 3. the planar integrated circularly polarized magnetoelectric dipole antenna of a kind of toothed opening according to claim 1, is characterized in that, can regulate its upper electric current by the stub length on the metal patch (5) of toothed opening The flow direction of the electric current is parallel to the long side (10) of the tooth-shaped opening metal patch (5). 4. The planar integrated circularly polarized magnetoelectric dipole antenna of a kind of toothed opening according to claim 1, is characterized in that, based on the basic principle of magnetoelectric dipole, in the first dielectric plate (1) Two rows of metallized through holes (4) are used to simulate the metal wall of the hammer of the all-metal magnetoelectric dipole, so that the equivalent magnetic current can be excited in the two rows of metallized through holes (4), by modifying the two toothed openings The shape of the metal patch (5) optimizes the current distribution on it, so that the current and the equivalent magnetic current can work together to generate two equal-amplitude orthogonal electric fields with a phase difference of 90° to realize circularly polarized radiation. 5. The planar integrated circularly polarized magnetoelectric dipole antenna of a kind of toothed opening according to claim 1, is characterized in that, the energy of microstrip line (9) is coupled to the first medium by slot (8) The metal vias (4) in the plate (1) and the tooth-shaped opening metal patches (5) on the upper layer excite circularly polarized radiation waves. 6 . The planar integrated circularly polarized magnetoelectric dipole antenna with a tooth-shaped opening according to claim 1 , wherein the antenna port adopts a microstrip feeding mode, and the input impedance of the port is 50 ohms.

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