A compact circularly polarized antenna applied to N78 frequency band

Abstract

The application discloses a compact circularly polarized antenna applied to an N78 frequency band, which comprises a metal patch, a dielectric substrate, a metal defective floor and a coaxial feeding probe; wherein the metal patch radiation structure is arranged on the upper surface of the dielectric substrate, and the metal defective floor structure is arranged on the lower surface of the dielectric substrate; the metal patch radiation structure comprises a circular patch with a cross-shaped slot in the center and two parasitic patches symmetrically arranged on the edges. The application provides a compact circularly polarized antenna applied to the N78 frequency band, which realizes compact circularly polarized radiation of the antenna structure by reasonably arranging the positions and shapes of the patch structures and processing the ring-shaped defects of the ground plate; the designed antenna structure is simple, has the characteristics of low profile and miniaturization, and can be applied to the new frequency band N78 frequency band of the 5G mobile communication system, and good results can be achieved through verification.

Description

Technical Field

[0001] This invention discloses a compact circularly polarized antenna for the N78 band, relating to the field of circularly polarized antenna technology. Background Technology

[0002] In 5G mobile communication systems, antennas, as components that receive and transmit electromagnetic waves, are already closely related to our lives, such as navigation, television, radar, broadcasting, and satellite wireless communication systems that require electromagnetic waves to transmit information. The performance of an antenna directly affects communication quality. This requires that antennas be designed to take into account complex environments and conditions, and to possess a certain degree of stability and anti-interference capability.

[0003] Circularly polarized antennas have stronger signal reception capabilities and can reduce signal fading caused by multipath and Faraday effects. Therefore, circular polarization technology can be well applied in wireless transmission systems. Similarly, compact antennas offer advantages such as improved space utilization, reduced costs, and solutions to space resource scarcity, aligning with the current development trend of base station antennas and representing a current international research hotspot. The N78 band, as a new frequency band for 5G mobile communication systems, is also attracting considerable attention.

[0004] Therefore, the problem that needs to be solved is how to broaden the impedance bandwidth of the existing circularly polarized antenna and achieve miniaturization to make it suitable for the N78 frequency band.

[0005] Content of this invention

[0006] The purpose of this invention is to provide a compact circularly polarized antenna for the N78 frequency band, thereby solving the problem of the lack of a simple, high-performance circularly polarized antenna suitable for the N78 frequency band in the prior art.

[0007] To achieve the above-mentioned technical objectives and effects, the invention is implemented through the following technical solution:

[0008] A compact circularly polarized antenna for the N78 band includes a metal patch, a dielectric substrate, a metal defect ground plane, and a coaxial feed probe; wherein the metal patch radiating structure is disposed on the upper surface of the dielectric substrate, and the metal defect ground plane structure is disposed on the lower surface of the dielectric substrate; characterized in that: the metal patch radiating structure includes a circular patch with a cross-shaped slit at the center and two parasitic patches symmetrically disposed on the edges.

[0009] Furthermore, the metal patch has a radial structure.

[0010] Furthermore, the cross-shaped slit has an asymmetrical structure, and the parasitic patch comprises two pieces that are centrally symmetrical.

[0011] Furthermore, the coaxial feed probe passes through the dielectric substrate, with its top end connected to a circular patch for power supply and its bottom end connected to a metal defect ground plane.

[0012] Furthermore, the top of the coaxial power supply probe is connected to the circular patch for power supply, and the power supply point is located at the upper right 70° direction of the circular patch, 7.5mm away from the center of the circular patch.

[0013] Furthermore, the long side of the cross-shaped slit has a length of L1 and a width of W1, and is offset from the center position by 30°;

[0014] The shorter side has a length of L2 and a width of W2, and is 22° off from the center.

[0015] Furthermore, the metal defect floor has four annular gaps arranged side by side and nested within each other.

[0016] Furthermore, the four annular gaps are the same size, and the difference between the outer and inner radii is 0.8 mm.

[0017] Another objective of this invention is to disclose an antenna having the aforementioned compact circularly polarized antenna applied to the N78 band, with an overall antenna size of 39.4mm × 39.4mm × 2mm.

[0018] Beneficial effects:

[0019] This invention provides a compact circularly polarized antenna for the N78 band. By rationally arranging the position and shape of the patch structure and treating the annular defect of the ground plane, the antenna structure achieves compact circularly polarized radiation. The designed antenna structure is simple, has low profile and miniaturization characteristics, and can be applied to the new N78 band of 5G mobile communication system. It has been verified to achieve good results.

[0020] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0021] Figure 1 This is a top view of the compact circularly polarized antenna used in the N78 band of this invention.

[0022] Figure 2 This is a side view of the compact circularly polarized antenna used in the N78 band of this invention.

[0023] Figure 3 This is a top view of the antenna structure of the metal patch radiating structure 1 in the example of the present invention.

[0024] Figure 4 This is a top view of the antenna structure of the metal defect ground plane 3 in an example of the present invention.

[0025] Figure 5 This is a surface current distribution diagram of the antenna of the metal patch radiating structure 1 in this embodiment of the invention when the antenna is operating at 3.5 GHz.

[0026] Figure 6 The diagram shows the antenna return loss and axial ratio bandwidth of the compact circularly polarized antenna in this embodiment of the invention.

[0027] Figure 7 The image shows the antenna gain diagram of the compact circularly polarized antenna in the embodiment.

[0028] In the attached image:

[0029] 1-Metal patch, 2-Dielectric substrate, 3-Metal defect ground plane, 4-Coaxial feed probe, 1-1-Circular patch, 1-2 Parasitic patch. Detailed Implementation

[0030] The fundamental principle of circularly polarized radiation by an antenna is that it generates two orthogonal modes with equal amplitude and a 90° phase difference. Based on this principle, this invention influences two electric field components (E) by loading two parasitic patches. θ and By changing the size of the parasitic patch, E can be altered. θ and The amplitudes are made approximately equal to achieve circular polarization characteristics. Simultaneously, by adding cross-shaped slots to the circular patch, the surface current path of the antenna is increased, widening the antenna's impedance bandwidth and enabling miniaturization.

[0031] To more clearly illustrate the technical solution of the present invention, the present invention will be described in detail below with reference to embodiments.

[0032] This embodiment provides a compact circularly polarized antenna for the N78 band, the structure of which is as follows: Figure 1 , Figure 2 As shown, it includes: a metal patch 1 radiating structure 1, a dielectric substrate 2, a metal defect ground 3, and a coaxial feed probe 4; wherein, the metal patch 1 radiating structure 1 is disposed on the upper surface of the dielectric substrate 2, and the metal defect ground 3 is disposed on the lower surface of the dielectric substrate 2.

[0033] Furthermore, the metal patch 1 radiation structure 1 consists of a circular patch 1-1 with a cross-shaped slot and two parasitic patches 1-2; the circular patch 1-1 is located at the center and has an asymmetrical cross-shaped slot loaded at its center, and the two parasitic patches 1-2 are arranged around the central circular patch 1-1. The two parasitic patches 1-2 are the same size, centrally symmetrical, and the edges of the parasitic patches 1-2 are flush with the edges of the dielectric substrate 2.

[0034] Furthermore, the coaxial power supply probe 4 is connected to the circular patch 1-1 at its top end for power supply. The power supply point is located at the upper right 70° direction of the circular patch 1-1, 7.5 mm away from the center of the circular patch 1-1.

[0035] The asymmetrical cross-shaped slits are located at the center of the metal radiating surface 1. The cross-shaped slits are centrally symmetrical, with a length of l1 and a width of w1, and are offset from the center position by 30°. The cross-shaped slits are also centrally symmetrical, with a length of l2 and a width of w2, and are offset from the center position by 22°.

[0036] The coaxial power supply probe 4 passes through the dielectric substrate 2, with its top end connected to the circular patch 1-1 for power supply and its bottom end connected to the metal ground plate 3.

[0037] Specifically, in this embodiment: the dielectric substrate 2 is an FR4-epoxy board with a dielectric constant of 4.4, a thickness of h = 2 mm, a diameter of d1 = 39.4 mm, a diameter of d2 = 1.3 mm for the coaxial feed probe 4, a radius of r1 = 17.4 mm for the circular patch, a distance of d3 = 5 mm between the circular patch and the parasitic patch, a long slit of the cross-shaped slit with a length of L1 = 7 mm and a width of W1 = 1.85 mm, a short slit of the cross-shaped slit with a length of L2 = 5 mm and a width of W2 = 2 mm, an inner radius of r2 = 3 mm and an outer radius of r3 = 2.8 mm for the annular slit, a distance of d4 = √5 mm between the centers of the two annular slits, and an inner radius of r4 = 15 mm and an outer radius of r5 = 19.7 mm for the fan-shaped slit.

[0038] Through simulation testing of the antenna provided in the embodiments of the present invention, it is found that the antenna performance can achieve the expected technical effect, which will be described in detail below.

[0039] like Figure 5 The diagram shows the surface current distribution of the metal radiating patch on the substrate operating at 3.5 GHz. It can be seen that with a 0° feed phase, the surface current is mainly concentrated in the lower right; with a 90° feed phase, it is mainly concentrated in the lower left; with a 180° feed phase, it is mainly concentrated in the upper left; and with a 270° feed phase, it is mainly concentrated in the upper right. The surface current of the antenna in the 0° and 90° feed phases is equal in magnitude but opposite in direction to that in the 180° and 270° feed phases. Therefore, this antenna can achieve right-hand circularly polarized radiation at 3.5 GHz.

[0040] Simulation tests were performed on the antenna provided in the embodiments of the present invention regarding antenna standing wave ratio (S11) and antenna axial ratio (AR). The simulation results are as follows: Figure 6As shown, the reflection coefficient of the antenna of the present invention is less than -10 in the frequency range of 3.52 to 3.85 GHz, and the -10 dB impedance bandwidth is 8.95%; the axial ratio coefficient of the antenna of the present invention is less than 3 in the frequency range of 3.70 to 3.75 GHz, and the 3 dB axial ratio bandwidth is 1.34%.

[0041] like Figure 7 The antenna of this invention has a maximum gain of 4.16 dBi within its operating frequency band.

[0042] In summary, the compact circularly polarized antenna for the N78 band provided by this invention is small in size, simple in structure, and has good circularly polarized radiation characteristics.

[0043] The above are merely some of the embodiments of this application and are not intended to limit the application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments shall still fall within the scope of protection of the technical solution of this application.

Claims

1. A compact circularly polarized antenna for use in the N78 band, comprising a metal patch, a dielectric substrate, a metal defect ground plane, and a coaxial feed probe; The metal patch radiation structure is disposed on the upper surface of the dielectric substrate, and the metal defect ground structure is disposed on the lower surface of the dielectric substrate; characterized in that: The metal patch radiation structure includes a circular patch with a cross-shaped slit in the center and two parasitic patches symmetrically arranged on the edge. The metal patch has a radial structure; The cross-shaped slit has an asymmetrical structure, and the parasitic patch comprises two pieces that are centrally symmetrical. The coaxial feed probe passes through the dielectric substrate, with its top end connected to a circular patch for power supply and its bottom end connected to a metal defect ground plane. The top of the coaxial feed probe is connected to the circular patch for power supply. The feed point is located at the upper right 70° direction of the circular patch and 7.5 mm away from the center of the circular patch. The long side of the cross-shaped slit has a length of L1 and a width of W1, and it is offset from the center position by 30°. The shorter side has a length of L2 and a width of W2, and is 22° off from the center. The metal defect floor has four annular gaps that are nested together and arranged side by side; The four annular gaps are the same size, and the difference between the outer and inner radii is 0.8 mm.

2. A compact circularly polarized antenna for the N78 band according to claim 1, characterized in that: The overall dimensions of the antenna are 39.4mm × 39.4mm × 2mm.

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