Broadband dual circularly polarized antenna

Abstract

The invention discloses a broadband dual circularly polarized antenna, which belongs to the technical field of antennas, and comprises a radiation layer, a metal reflection cavity and an L-shaped metal sheet, the radiation layer is a circular metal sheet, and one side of the circular metal sheet is provided with two parallel rectangular grooves to form an E-shaped structure with three metal arms. The top of a vertical branch of the L-shaped metal sheet is connected with the middle metal arm, and a horizontal branch of the L-shaped metal sheet is parallel to the bottom plate of the metal reflection cavity and has a gap; the circular metal sheet is connected with the metal reflection cavity bottom plate through the central metal column; the upper surface of the metal reflection cavity bottom plate is provided with a discontinuous circular trapezoidal metal bulge; two connectors are arranged on the lower surface of the bottom plate of the metal reflection cavity; an outer conductor of the connector is connected with the reflection cavity, and an inner conductor of the connector penetrates through the metal reflection cavity bottom plate and is connected with the corresponding side edge metal arm. According to the invention, a wider frequency range is effectively covered, and surface current distribution is optimized.

Description

Technical Field

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

[0002] With the development and advancement of modern wireless communication technology, especially the rapid growth of mobile satellite communications and the mobile internet since the turn of the century, the volume of wireless data transmission and exchange has continued to increase, and the baud rate of transmitted data has continued to rise. The increasing demand for communication speed and quality has driven the development of antennas towards broadband and multi-polarization. Compared to single-polarization antennas, dual-polarization antennas, while increasing system complexity to a certain extent, also offer significant advantages. First, dual-polarized antennas can carry twice as much information as single-polarized antennas, which is equivalent to adding a communication channel and doubling the frequency band utilization. Second, the polarization agility of dual-polarized antennas is very important. Although the two polarizations of a dual-polarized antenna cannot usually operate simultaneously, certain devices can be used to enable the two polarizations of a dual-polarized antenna to operate alternately. This method is much more efficient than using antennas with two polarizations alone. In addition, dual-polarized antennas can simultaneously transmit and receive two orthogonal signals in the same frequency band. The two polarized electromagnetic waves do not interfere with each other, effectively eliminating the impact of multipath effects and improving the reception quality of communication signals. Finally, dual-polarized antennas can reduce the number of antennas in communication equipment, saving system space, avoiding the potential mutual coupling effect between multiple antennas, and improving the communication quality of the system.

[0003] A dual circularly polarized antenna is one with two ports. When one port is excited, the antenna radiates right-hand circularly polarized waves, while when the other port is excited, the antenna radiates left-hand circularly polarized waves. Dual circularly polarized antennas are typically implemented using dual linearly polarized antennas. This is achieved by orthogonally configuring two linearly polarized elements within the same aperture. The feed ends of the two elements are connected to a circularly polarized bridge, and vector synthesis is achieved through the circularly polarized radiation bridge to produce left-hand and right-hand circularly polarized radiation. A cross dipole antenna is a typical example of this type of dual circularly polarized antenna. Similarly, orthogonal dual linear polarization signals can be achieved by configuring different feeding methods on the same aperture or structure. Alternatively, left-hand and right-hand circularly polarized radiation can be achieved through the use of a circularly polarized bridge. Dual circularly polarized horn antennas and dual circularly polarized microstrip antennas are typical structures for this implementation. Although dual circularly polarized antenna designs can achieve dual circular polarization characteristics due to their multi-layer stacked structure and complex feeding network, they generally have disadvantages such as large size, complex structure, heavy weight, and high cost. Especially when operating in high-frequency bands, the performance of the antenna is easily affected by processing errors and environmental factors, resulting in a decrease in polarization isolation and a deterioration of the axial ratio, limiting its application in broadband communication systems. Summary of the Invention

[0004] The purpose of the present invention is to address the defects and shortcomings of the existing technology and provide a design method for a broadband dual circularly polarized antenna that does not require a circularly polarized bridge. By optimizing the antenna's radiation structure and feeding method, the antenna's broadband dual circularly polarized radiation is achieved.

[0005] The present invention is achieved through the following technical solutions:

[0006] A broadband dual circularly polarized antenna comprises a radiating layer, a metal reflective cavity, and an L-shaped metal sheet; the radiating layer is a circular metal sheet, one side of which is provided with two parallel rectangular grooves, forming an E-shaped structure with three metal arms;

[0007] The top of the vertical branch of the L-shaped metal sheet is connected to the middle metal arm, and the horizontal branch is parallel to the bottom plate of the metal reflector cavity with a gap; the circular metal sheet is connected to the bottom plate of the metal reflector cavity through the central metal column;

[0008] The upper surface of the metal reflective cavity bottom plate is provided with a discontinuous circular trapezoidal metal protrusion;

[0009] Two connectors are provided on the lower surface of the metal reflection cavity bottom plate; the outer conductor of the connector is connected to the reflection cavity, and the inner conductor passes through the metal reflection cavity bottom plate and is connected to the corresponding side metal arm.

[0010] Furthermore, the metal reflection cavity includes a base plate and a metal flange; the base plate is circular, the metal flange array is at the edge of the base plate and is perpendicular to the base plate; the metal flange is an arc-shaped plate, and the bottom edge of the arc-shaped plate is in close contact with the edge of the base plate.

[0011] Furthermore, the discontinuous circular trapezoidal metal protrusions are a plurality of arc-shaped protrusions arranged in an array along a circumference, and the cross-section of the arc-shaped protrusions is trapezoidal.

[0012] Furthermore, the array center of the metal flanges coincides with the array center of the arc-shaped protrusions, and the distribution of the metal flanges and the arc-shaped protrusions is a complementary distribution centered on the center of the metal reflective cavity.

[0013] Furthermore, the L-shaped metal sheet and the circular metal sheet are an integrated structure; the circular metal sheet and the metal reflection cavity bottom plate are parallel to each other.

[0014] Furthermore, one end of the central metal column is connected to the radiation layer, and the other end is connected to the metal reflection cavity bottom plate.

[0015] Furthermore, it also includes two side metal pillars; the two side metal pillars are respectively installed at the bottom of the corresponding side metal arms, the side metal pillars have no contact with the metal reflection cavity bottom plate, and the bottom of the side metal pillars is connected to the inner conductor of the corresponding connector.

[0016] Furthermore, the circular metal sheet of the radiation layer is replaced by a rectangular or elliptical metal sheet; and the bottom plate of the metal reflection cavity is set to a rectangular metal bottom plate that matches the radiation layer.

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

[0018] 1. The present invention provides a broadband dual circularly polarized antenna comprising a radiating layer, a metal reflective cavity, and an L-shaped metal sheet. By optimizing the size of the metal arms and the position of the feed points, and thus the current distribution on the radiating layer surface, the antenna can achieve dual circularly polarized signal radiation without the need for a circularly polarized bridge. Simultaneously, the three metal arms of the E-shaped structure can excite multimode resonance, resulting in the antenna having excellent broadband characteristics and ultimately achieving a relative impedance bandwidth greater than 35%. Compared with traditional dual circularly polarized antennas, no additional bridge is required, resulting in a simple and compact antenna structure and excellent broadband dual circularly polarized radiation characteristics.

[0019] 2. The antenna structure of the present invention adopts an integrated design and a compact metal reflection cavity, avoiding the complexity of the traditional multi-layer stacked structure, and has the advantages of easy processing, simple assembly, and easy installation; at the same time, it can realize an all-metal structure, greatly improving the reliability of the antenna, and can be used in various application scenarios such as air, sky, land, and sea.

[0020] 3. The present invention is based on the improvement and optimization of the air microstrip antenna structure. The antenna cross-section height is less than 0.12λ, which has the advantages of low cross-section and high radiation efficiency.

[0021] In summary, the broadband dual circularly polarized antenna of the present invention has significant advantages in bandwidth, polarization performance, compact structure, low profile, low cost, etc., can meet the needs of modern wireless communication systems for high-performance antennas, and has broad application prospects and market potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an overall structural diagram of an embodiment of the present invention;

[0023] Figure 2 yes Figure 1 Schematic diagram of the structure of the middle radiation layer;

[0024] Figure 3 yes Figure 1 Schematic diagram of the structure of the metal reflection cavity;

[0025] In the figure: 1. Metal reflective cavity; 2. Radiation layer; 3. Discontinuous circular trapezoidal metal protrusion; 4. Connector; 2-1. Circular metal sheet; 2-2. Center metal column; 2-3. Side metal column; 1-1. Bottom plate; 1-2. Metal flange. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] A broadband dual circularly polarized antenna comprises a radiating layer, a metal reflective cavity, and an L-shaped metal sheet; the radiating layer is a circular metal sheet, one side of which is provided with two parallel rectangular grooves, forming an E-shaped structure with three metal arms;

[0028] The top of the vertical branch of the L-shaped metal sheet is connected to the middle metal arm, and the horizontal branch is parallel to the bottom plate of the metal reflector cavity with a gap; the circular metal sheet is connected to the bottom plate of the metal reflector cavity through the central metal column;

[0029] The upper surface of the metal reflective cavity bottom plate is provided with a discontinuous circular trapezoidal metal protrusion;

[0030] Two connectors are provided on the lower surface of the metal reflection cavity bottom plate; the outer conductor of the connector is connected to the reflection cavity, and the inner conductor passes through the metal reflection cavity bottom plate and is connected to the corresponding side metal arm.

[0031] Furthermore, the metal reflection cavity includes a base plate and a metal flange; the base plate is circular, the metal flange array is at the edge of the base plate and is perpendicular to the base plate; the metal flange is an arc-shaped plate, and the bottom edge of the arc-shaped plate is in close contact with the edge of the base plate.

[0032] Furthermore, the discontinuous circular trapezoidal metal protrusions are a plurality of arc-shaped protrusions arranged in an array along a circumference, and the cross-section of the arc-shaped protrusions is trapezoidal.

[0033] Furthermore, the array center of the metal flanges coincides with the array center of the arc-shaped protrusions, and the distribution of the metal flanges and the arc-shaped protrusions is a complementary distribution centered on the center of the metal reflective cavity.

[0034] Furthermore, the L-shaped metal sheet and the circular metal sheet are an integrated structure; the circular metal sheet and the metal reflection cavity bottom plate are parallel to each other.

[0035] Furthermore, one end of the central metal column is connected to the radiation layer, and the other end is connected to the metal reflection cavity bottom plate.

[0036] Furthermore, it also includes two side metal pillars; the two side metal pillars are respectively installed at the bottom of the corresponding side metal arms, the side metal pillars have no contact with the metal reflection cavity bottom plate, and the bottom of the side metal pillars is connected to the inner conductor of the corresponding connector.

[0037] Furthermore, the circular metal sheet of the radiation layer is replaced by a rectangular or elliptical metal sheet; and the bottom plate of the metal reflection cavity is set to a rectangular metal bottom plate that matches the radiation layer.

[0038] The following is a more specific embodiment:

[0039] Reference Figures 1 to 3 ,This embodiment mainly consists of a radiation layer, a metal reflection cavity, an L-shaped metal sheet and a connector;

[0040] The radiating layer consists of a circular metal sheet with two slots, each symmetrically oriented about one of the sheet's diameters. The two slots are oriented in the same direction, giving the sheet an E-shaped structure. The E-shaped structure consists of three metal arms: two side arms and a center arm. In this embodiment, the end of the center arm is bent downward.

[0041] The main body of the metal reflective cavity is the bottom plate and the four non-continuous metal flanges on the edge of the bottom plate; the four metal flanges are all arc-shaped plates, and the four arc-shaped plates are located in the same circumference, which coincides with the center of the bottom plate. The bottom edge of the arc-shaped plate and the edge of the bottom plate are matched and connected to form an integrated structure. Four non-continuous circular trapezoidal metal protrusions are set on the upper surface of the bottom plate; the circular trapezoidal metal protrusions are arc-shaped protrusions, and their cross-sections are trapezoidal. The array centers of both the arc-shaped protrusions and the arc-shaped plates coincide with the center of the bottom plate. For specific reference Figure 3 The metal flange and the trapezoidal protrusion are distributed in a complementary manner with the center of the metal reflection cavity as the center.

[0042] The center of the E-shaped structure of the radiation layer is connected to the center of the metal reflector cavity bottom plate through the central metal column. The end of the middle metal arm of the E-shaped structure is bent and connected to the top of the vertical branch of the L-shaped metal sheet. The horizontal branches of the L-shaped metal sheet face the outside of the E-shaped structure and are parallel to the bottom plate with a spacing greater than zero.

[0043] There are two connectors, corresponding to the side metal columns at the bottom of the side metal arms of the E-shaped structure; the top of the side metal column is connected to the corresponding metal arm, and the bottom is suspended in the air without contact with the bottom plate; the outer conductor of the connector is connected to the bottom plate, and the inner conductor is connected to the corresponding side metal column.

[0044] In other embodiments: the circular metal sheet of the radiation layer is replaced by a rectangular or elliptical metal sheet; the bottom plate of the metal reflection cavity is set to a rectangular metal bottom plate matching the radiation layer.

[0045] Brief working principle of the present invention:

[0046] The present invention operates in the following manner: A broadband dual-circularly polarized antenna comprises a radiating layer, a metal reflector cavity, and an L-shaped metal sheet. The radiating layer is an E-shaped structure with three metal arms. The dual-circular polarization feed is located on the two outer metal arms. By optimizing the metal arm dimensions and feed point positions, the current distribution on the radiating layer surface is optimized, forming two orthogonal current modes with equal amplitudes. By varying the feed positions, the two current modes can lead / lag by 90°, thereby achieving dual-circular polarization radiation. The discontinuous surrounding edge of the metal reflector cavity and the complementary distribution of trapezoidal metal protrusions suppress cross-polarization components and improve the isolation of left-handed and right-handed circularly polarized signals. The three metal arms of the E-shaped structure can excite multimode resonance. The downward folding middle metal arm couples with the metal reflector cavity floor, achieving broadband impedance matching for the antenna and thus achieving broadband dual-circular polarization signal radiation. This broadband dual-circularly polarized antenna has a relative bandwidth greater than 35% and a profile height less than 0.12λ, enabling a fully metallized design. It exhibits excellent dual-circular polarization radiation characteristics, as well as the advantages of wide bandwidth and low profile.

[0047] It should be noted that the above description is only an example of a preferred application of the present invention and is not intended to limit the scope of protection of the present invention. Any technical solution that adopts equivalent replacement or equivalent transformation is within the scope of protection of the present invention.

Claims

1. A broadband dual circularly polarized antenna, comprising a radiation layer, a metal reflective cavity, and an L-shaped metal sheet; characterized in that: The radiation layer is a circular metal sheet with two parallel rectangular grooves on one side, forming an E-shaped structure with three metal arms; The top of the vertical branch of the L-shaped metal sheet is connected to the middle metal arm, and the horizontal branch is parallel to the bottom plate of the metal reflector cavity with a gap; the circular metal sheet is connected to the bottom plate of the metal reflector cavity through the central metal column; The upper surface of the metal reflective cavity bottom plate is provided with a discontinuous circular trapezoidal metal protrusion; Two connectors are provided on the lower surface of the metal reflection cavity bottom plate; the outer conductor of the connector is connected to the reflection cavity, and the inner conductor passes through the metal reflection cavity bottom plate and is connected to the corresponding side metal arm.

2. A broadband dual circularly polarized antenna according to claim 1, characterized in that: The metal reflection cavity includes a bottom plate and a metal flange; the bottom plate is circular, the metal flange array is at the edge of the bottom plate and is perpendicular to the bottom plate; the metal flange is an arc-shaped plate, and the bottom edge of the arc-shaped plate is in close contact with the edge of the bottom plate.

3. A broadband dual circularly polarized antenna according to claim 2, characterized in that: The discontinuous circular trapezoidal metal protrusions are a plurality of arc-shaped protrusions arranged in an array along a circumference, and the cross-section of the arc-shaped protrusions is a trapezoid.

4. The broadband dual circularly polarized antenna according to claim 3, characterized in that: The array center of the metal flanges coincides with the array center of the arc-shaped protrusions, and the distribution of the metal flanges and the arc-shaped protrusions is a complementary distribution centered on the center of the metal reflective cavity.

5. The broadband dual circularly polarized antenna according to claim 1, wherein: The L-shaped metal sheet and the circular metal sheet are an integrated structure; the circular metal sheet and the metal reflection cavity bottom plate are parallel to each other.

6. The broadband dual circularly polarized antenna according to claim 1, characterized in that: One end of the central metal column is connected to the radiation layer, and the other end is connected to the metal reflection cavity bottom plate.

7. The broadband dual circularly polarized antenna according to claim 1, characterized in that: It also includes two side metal columns; the two side metal columns are respectively installed at the bottom of the corresponding side metal arms, the side metal columns have no contact with the metal reflection cavity bottom plate, and the bottom of the side metal columns is connected to the inner conductor of the corresponding connector.

8. The broadband dual circularly polarized antenna according to claim 1, characterized in that: The circular metal sheet of the radiation layer is replaced by a rectangular or elliptical metal sheet; the bottom plate of the metal reflection cavity is set to a rectangular metal bottom plate matching the radiation layer.

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