Ka-band circularly polarized planar reflective array unit and antenna

Abstract

The application discloses a Ka-band circularly polarized planar reflective array unit and an antenna, and the array unit comprises an upper dielectric substrate, a lower dielectric substrate and a metal ground plate; the upper dielectric substrate is provided with a rectangular radiation patch at a central position; the rectangular radiation patch is provided with a slot at the center; the two sides of the rectangular radiation patch are symmetrically provided with trapezoidal radiation patches and strip-shaped rectangular radiation patches; the trapezoidal radiation patches are located inside the strip-shaped rectangular radiation patches; the lower dielectric substrate is symmetrically provided with trapezoidal radiation patches and strip-shaped rectangular radiation patches on the two sides; the trapezoidal radiation patches are located inside the strip-shaped rectangular radiation patches; the directions of the radiation patches on the two sides of the lower dielectric substrate are orthogonal to the directions of the radiation patches on the two sides of the upper dielectric substrate; and the metal ground plate is tightly attached to the lower dielectric substrate; the antenna comprises N*N Ka-band circularly polarized planar reflective array units and a linearly polarized feed source with good performance. The application solves the problems of low aperture efficiency of the planar reflective array and the problems of the circularly polarized planar reflective array in dealing with electromagnetic interference and multipath effects.

Description

TECHNICAL FIELD

[0001] The application relates to a planar reflective array, in particular to a Ka-band circularly polarized planar reflective array unit and antenna. BACKGROUND

[0002] For long-distance communication, high gain and high aperture efficiency are important reference indexes, which depend on the size of the antenna and the energy loss of the system.

[0003] Traditional high-gain antennas mainly include parabolic antennas and phased array antennas. The parabolic antenna has a large three-dimensional structure, resulting in a high overall profile and a large occupied area, which is difficult to integrate into a wireless system. The traditional phased array antenna has a complex feed network, resulting in complex design and high processing cost. Compared with the traditional parabolic antenna and phased array antenna, the planar reflective array antenna has the advantages of low profile, low cost, simple deployment and easy movement, and has potential application value in satellite / space communication, automobile / airborne radar, low-cost beam scanning and other application scenarios.

[0004] Most existing reflective array antennas are linearly polarized, but for satellite communication systems, electromagnetic interference and multipath effects caused by complex environments can easily lead to polarization misalignment and power transmission loss. Circularly polarized waves have strong robustness to environmental interference, and circularly polarized antennas can effectively avoid this problem.

[0005] Therefore, how to realize low profile, high gain and circular polarization performance is a key and difficult problem in the planar reflective array. Although the traditional high-gain antenna can be used, it is necessary to ensure that the structure is simple, easy to process and low cost, while ensuring high aperture efficiency and realizing circular polarization performance, which puts forward higher requirements for antenna engineers. SUMMARY

[0006] The application aims to provide a Ka-band circularly polarized planar reflective array unit and antenna, which solves the problems of low aperture efficiency of the planar reflective array and the problems of circularly polarized planar reflective array in response to electromagnetic interference and multipath effects.

[0007] The technical scheme for achieving the application is as follows:

[0008] A Ka-band circularly polarized planar reflective array unit, comprising an upper layer dielectric substrate, a lower layer dielectric substrate and a metal floor, the upper layer dielectric substrate has a rectangular radiation patch at the center position, the rectangular radiation patch is centrally slotted, both sides of the upper layer dielectric substrate are symmetrically provided with a trapezoidal radiation patch and a strip-shaped rectangular radiation patch, and the trapezoidal radiation patch is located inside the strip-shaped rectangular radiation patch; both sides of the lower layer dielectric substrate are symmetrically provided with a trapezoidal radiation patch and a strip-shaped rectangular radiation patch, the trapezoidal radiation patch is located inside the strip-shaped rectangular radiation patch, and the radiation patches on both sides of the lower layer dielectric substrate are orthogonal to the radiation patches on both sides of the upper layer dielectric substrate, and the metal floor is closely attached to the lower layer dielectric substrate; the size of the pair of trapezoidal radiation patches and the pair of strip-shaped rectangular radiation patches on the upper layer dielectric substrate is the same, and the size of the pair of trapezoidal radiation patches and the pair of strip-shaped rectangular radiation patches on the lower layer dielectric substrate is the same.

[0009] Further, the rectangular radiation patch has a degree of 0.8a and a width of 0.8b, and the slot has a length of 0.2a and a width of 0.2b, wherein a and b are adjustable parameters, the phase difference corresponding to the initial values of a and b is 90°, the change range of the adjustable parameter a is 1-2.2mm, and the change range of the parameter b is 1-2.2mm.

[0010] Further, the trapezoidal radiation patch of the upper layer dielectric substrate has a short bottom edge length of 0.8a, a long bottom edge length of 1.6a and a height of 0.1a, and the strip-shaped rectangular radiation patch has a length of 2a and a width of 0.1mm; the long bottom edge of the trapezoidal radiation patch is 0.3mm away from the strip-shaped rectangular radiation patch.

[0011] Further, the trapezoidal radiation patch of the lower layer dielectric substrate has a short bottom edge length of 0.8b, a long bottom edge length of 1.6b and a height of 0.1b, and the strip-shaped rectangular radiation patch has a length of 2b and a width of 0.1mm; the long bottom edge of the trapezoidal radiation patch is 0.3mm away from the strip-shaped rectangular radiation patch.

[0012] Further, the upper layer dielectric substrate and the lower layer dielectric substrate are square.

[0013] Further, the side length of the upper layer dielectric substrate and the lower layer dielectric substrate is 5mm, the thickness of the upper layer dielectric substrate is 0.254mm, and the thickness of the lower layer dielectric substrate is 0.12mm.

[0014] A Ka-band circularly polarized planar reflective array antenna, comprising N*N Ka-band circularly polarized planar reflective array units and a linearly polarized feed source with good performance, the radiation patch size of each array unit is different, the corresponding size of the unit is selected according to the compensation phase of the array unit at different positions, and the reflective array unit is gradually arranged periodically.

[0015] Furthermore, the phase compensation φ of the i-th array element i =2nπ+k0(R) i +r i r0), n=0,1,2...,R i r represents the position vector from the feed phase center to the i-th array element on the array surface. i r0 represents the position vector from the center of the array to the i-th array element, r0 represents the unit vector along the main beam direction, and k0 represents the number of wavelengths in free space.

[0016] Furthermore, N=9, the upper dielectric substrate of the antenna has a side length of 45mm and a thickness of 0.254mm, the lower dielectric substrate has a total side length of 45mm and a thickness of 1.2mm, and the metal ground plane has a side length of 45mm.

[0017] Furthermore, a high-performance horn antenna is used as the feed source, with specific dimensions of 152mm in length, 119mm in width, and 254mm in height. The waveguide structure has a length of 86mm, a width of 43mm, and a height of 83mm. The antenna is made of PEC material, which has good return loss. The horn antenna is located directly above the center of the reflector array, with its aperture surface 51mm away from the reflector array surface, and is placed diagonally on the reflector array.

[0018] Compared with the prior art, the significant advantages of this invention are as follows: This invention uses a high-performance horn antenna as the feed source and is made of PEC material, which has good return loss; This invention designs and implements a circularly polarized planar reflector array with high aperture efficiency, which has a simple structure, is easy to process, and has the characteristics of high aperture efficiency and circular polarization performance, and has potential application value in satellite communication systems. Attached Figure Description

[0019] Figure 1 This is a top view of the Ka-band circularly polarized planar reflector array antenna unit structure.

[0020] Figure 2 This is an axonometric view of the Ka-band circularly polarized planar reflector array antenna unit structure.

[0021] Figure 3 This is a phase shift range diagram for a Ka-band circularly polarized planar reflective array antenna element.

[0022] Figure 4 The axial ratio diagram is shown for a Ka-band circularly polarized planar reflective array antenna element.

[0023] Figure 5 This is a top view of the Ka-band circularly polarized planar reflector array antenna structure.

[0024] Figure 6A side view of a Ka-band circularly polarized planar reflective array antenna structure.

[0025] Figure 7 A gain pattern of a Ka-band circularly polarized planar reflective array antenna.

[0026] Figure 8 A gain bandwidth pattern of a Ka-band circularly polarized planar reflective array antenna.

[0027] Figure 9 An axial ratio bandwidth pattern of a Ka-band circularly polarized planar reflective array antenna.

[0028] Label explanation: 1-first rectangular radiation patch, 2-first trapezoidal radiation patch, 3-first strip-shaped rectangular radiation patch, 4-second trapezoidal radiation patch, 5-second strip-shaped rectangular radiation patch, 6-upper layer dielectric substrate, 7-lower layer dielectric substrate, 8-horn antenna, 9-planar reflective array antenna. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0030] Embodiment 1

[0031] This embodiment is a Ka-band circularly polarized planar reflective array antenna unit structure, which combines Figure 1 and Figure 2The unit structure is composed of two square dielectric substrates, three different shapes of radiation patches and a metal ground plate. The radiation patches are fixed on the two dielectric substrates respectively, and the position distribution is as follows: the upper dielectric substrate 6 has a side length of 5 mm and a thickness of 0.254 mm. There is a first rectangular radiation patch 1 with a central slot in the center position of the dielectric plate, and the length of the slot is Lx5=0.2a, the width is Ly5=0.2b, the length of the first rectangular radiation patch 1 with a slot is Lx4=0.8a, and the width is Ly4=0.8b; there is a pair of first trapezoidal radiation patches 2 of the same size in the same layer, the length of the short bottom edge is Lx3=0.8a, the length of the long bottom edge is Lx2=1.6a, and the height is wx1=0.1a; there is a pair of first strip-shaped rectangular radiation patches 3 of the same size outside the trapezoidal radiation patch, the length is Lx1=2a, and the width is wx0=0.1 mm. The long bottom edge of the first trapezoidal radiation patch 2 is 0.3 mm away from the first strip-shaped rectangular radiation patch 3 G01. The lower dielectric substrate 7 has a side length of 5 mm and a thickness of 1.2 mm, and there is a pair of second trapezoidal radiation patches 4 and a pair of second strip-shaped rectangular radiation patches 5 on the lower dielectric substrate. The second trapezoidal radiation patch 4 has a short bottom edge of Ly3=0.8b, a long bottom edge length of Ly2=1.6b, and a height of wy1=0.1b; the second strip-shaped rectangular radiation patch 5 has a length of Ly1=2b and a width of wy0=0.1 mm. The long bottom edge of the second trapezoidal radiation patch 4 is 0.3 mm away from the second strip-shaped rectangular radiation patch 5 G01. The parameter a ranges from 1 to 2.2 mm, and the parameter b ranges from 1 to 2.2 mm. By changing the parameter a, the phase shift range of the unit is adjusted, and during the adjustment, b=a, Figure 3 For different frequencies, the unit has a phase shift range of 500° as the parameter a changes, and the metal ground plate is closely attached to the lower dielectric substrate.

[0032] The basic principle of realizing circular polarization of the unit is that the unit structure has two mutually perpendicular (phase difference of 90°) and equal electric fields or magnetic fields in the orthogonal direction, so as to form circularly polarized radiation. On the phase shift curve of the unit, first determine a value a1 of the parameter a, and select a value a2 of the parameter a corresponding to a phase difference of 90°. Let the unit a=a1, b=a2, then the unit has a phase difference of 90° in the orthogonal direction, which satisfies the circular polarization condition, that is, a circularly polarized reflection unit is formed. Figure 4 For the axial ratio characteristic analysis of a reflection unit with a parameter a=1.2 mm and a parameter b=1.46 mm size, it is shown that the unit structure has good circular polarization characteristics.

[0033] A Ka-band circularly polarized planar reflective array antenna, comprising N*N of the Ka-band circularly polarized planar reflective array units and a linearly polarized feed source, the radiation patch size of each array unit is different, and the corresponding size of the unit is selected according to the compensation phase of the array unit at different positions, and the gradual periodic arrangement of the reflective array unit is carried out.

[0034] Embodiment 2

[0035] This embodiment provides a Ka-band circularly polarized planar reflective array antenna structure, as shown in Figure 5 and Figure 6 The structure of the planar reflective array antenna 9 is composed of two square dielectric substrates, a metal floor and 9*9 unit radiation patches of different sizes. The upper dielectric substrate has a side length of 45mm and a thickness of 0.254mm, the lower dielectric substrate has a side length of 45mm and a thickness of 1.2mm, and the metal floor has a side length of 45mm. Different sizes of unit radiation patches are distributed on the upper and lower dielectric substrates. In order to achieve good antenna planarization, the planar reflective unit needs to have a phase shift range of at least 360° or more. Because the transmission path distances from the phase center of the feed source to each reflective unit of the array surface are different, the phases of the incident waves reaching each reflective unit are different. In order to achieve an equal phase surface in a specific direction, the phase of each reflective unit must be compensated according to the phase curve of the reflective unit. After the height of the feed source and the aperture of the reflective array are determined, the phase that needs to be adjusted for the i th reflective unit in the array is calculated according to the formula φ i =2nπ+k0(R i +r i r0),n=0,1,2... When n=0 and the main beam of the planar reflective array antenna is directed to the normal of the array surface, the required phase compensation of each unit is φ=k·Δd. Wherein, R i represents the position vector from the phase center of the feed source to the i th reflective unit of the array surface, r i represents the position vector from the center of the array surface to the i th reflective unit of the array surface, r0 represents the unit vector along the main beam direction, and k0 represents the wavelength number in free space. Δd is the optical path difference between the phase center and the center of the planar reflective array surface. After calculating the required compensation phase of the reflective unit at different positions, the gradual periodic arrangement of the reflective array unit is carried out according to Figure 3The phase shift range diagram of the unit is used to select appropriately sized units for a gradually changing periodic arrangement of the reflective array units. First, the 'a' parameter of the unit is determined when the compensated phase value is 0. The phase value corresponding to this point is set as the initial phase value. The phase values ​​of the remaining units are the sum of the initial phase value and the compensated phase value at that position. The 'a' parameter is determined based on the phase values. Further, the value corresponding to a phase difference of 90° from the 'a' parameter is selected as the 'b' value. After determining the 'a' and 'b' parameters of the unit, the size of the radiating patch for that unit can be determined. Only the radiating patch portion of the unit is arranged in a gradually changing periodic pattern. The upper and lower radiating patches are placed on the upper and lower dielectric substrates, respectively, with the outermost strip-shaped rectangular radiating patches of each unit connected together.

[0036] This invention uses a high-performance horn antenna 8 as the feed source. Specific dimensions are: horn aperture length 152mm, width 119mm, and height 254mm. The waveguide structure has a length of 86mm, a width of 43mm, and a height of 83mm. The horn antenna is made of PEC material, exhibiting good return loss. When calculating the phase value to be compensated by the calculation unit, the optimal focal length ratio of 0.8 and an aperture of 45mm × 45mm are initially selected, determining the feed source height to be 52mm. The horn antenna position is then determined to be directly above the center of the reflector array, with its aperture surface 52mm from the reflector surface, positioned diagonally on the reflector surface. During optimization, a feed source height of 51mm was ultimately determined to provide the best antenna performance.

[0037] Figure 7 The gain pattern of the planar reflector array antenna at a center frequency of 30 GHz is shown. The results show that the antenna has good left-hand circular polarization performance with a gain of 21.2 dBi and an aperture efficiency of 51.8%. Figure 8 and Figure 9 The changes in gain and axial ratio of the planar reflective array antenna within a certain frequency range indicate that when the operating frequency fluctuates between 29.5-30 GHz, the antenna gain is still no less than 20 dBi, the aperture efficiency is no less than 40%, and it has good left-hand circular polarization performance.

[0038] In summary, this invention is a Ka-band circularly polarized planar reflective array antenna with high aperture efficiency and good circular polarization performance, and has potential application value in the field of satellite communication.

Claims

1. A Ka-band circularly polarized planar reflective array unit, characterized in that, The application relates to a Ka-band circularly-polarized planar reflectarray unit and a linearly-polarized feed source. The length of the rectangular radiation patch is 0.8a, the width is 0.8b, the length of the slot is 0.2a, and the width is 0.2b, wherein a and b are adjustable parameters, the phase difference corresponding to the initial values of a and b is 90 DEG, the change range of the adjustable parameter a is 1-2.2mm, and the change range of the parameter b is 1-2.2mm. The length of the rectangular radiation patch is 0.8a, the width is 0.8b, the length of the slot is 0.2a, and the width is 0.2b, wherein a and b are adjustable parameters, the phase difference corresponding to the initial values of a and b is 90 DEG, the change range of the adjustable parameter a is 1-2.2mm, and the change range of the parameter b is 1-2.2mm. The length of the rectangular radiation patch is 0.8a, the width is 0.8b, the length of the slot is 0.2a, and the width is 0.2b, wherein a and b are adjustable parameters, the phase difference corresponding to the initial values of a and b is 90 DEG, the change range of the adjustable parameter a is 1-2.2mm, and the change range of the parameter b is 1-2.2mm.

2. The Ka-band circularly polarized planar reflective array unit of claim 1, wherein, The length of the rectangular radiation patch is 0.8a, the width is 0.8b, the length of the slot is 0.2a, and the width is 0.2b, wherein a and b are adjustable parameters, the phase difference corresponding to the initial values of a and b is 90 DEG, the change range of the adjustable parameter a is 1-2.2mm, and the change range of the parameter b is 1-2.2mm.

3. The Ka-band circularly polarized planar reflective array unit of claim 2, wherein, The upper layer dielectric substrate and the lower layer dielectric substrate are square.

4. A Ka-band circularly polarized planar reflective array antenna, characterized in that, The length of the rectangular radiation patch is 0.8a, the width is 0.8b, the length of the slot is 0.2a, and the width is 0.2b, wherein a and b are adjustable parameters, the phase difference corresponding to the initial values of a and b is 90 DEG, the change range of the adjustable parameter a is 1-2.2mm, and the change range of the parameter b is 1-2.2mm.

5. The Ka-band circularly polarized planar reflective array antenna of claim 4, wherein, The phase compensation phase φ of the i-th array unit i = 2nπ + k0(R i + r i r0), n = 0, 1, 2... i represents the position vector of the phase center of the feed to the i-th array unit of the array surface, r i represents the position vector of the array center to the i-th array unit of the array surface, r0 represents the unit vector along the main beam direction, and k0 represents the wavelength number in free space.

6. The Ka-band circularly polarized planar reflective array antenna of claim 4, wherein, The length of the rectangular radiation patch is 0.8a, the width is 0.8b, the length of the slot is 0.2a, and the width is 0.2b, wherein a and b are adjustable parameters, the phase difference corresponding to the initial values of a and b is 90 DEG, the change range of the adjustable parameter a is 1-2.2mm, and the change range of the parameter b is 1-2.2mm.

7. The Ka-band circularly polarized planar reflective array antenna of claim 6, wherein, The length of the rectangular radiation patch is 0.8a, the width is 0.8b, the length of the slot is 0.2a, and the width is 0.2b, wherein a and b are adjustable parameters, the phase difference corresponding to the initial values of a and b is 90 DEG, the change range of the adjustable parameter a is 1-2.2mm, and the change range of the parameter b is 1-2.2mm.

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