Cross-band dual-frequency co-boresight composite planar reflector antenna

Abstract

The application provides a cross-band dual-frequency common-aperture composite planar reflector antenna, which comprises a grounding layer, a structure layer and an intermediate layer, the structure layer is provided with alternately arranged first annular units and second annular units, the diameter of the first annular units is larger than that of the second annular units, and the number of the second annular units is more than that of the first annular units; and the intermediate layer is arranged between the grounding layer and the structure layer. The cross-band dual-frequency common-aperture composite planar reflector antenna can realize large frequency division ratio cross-band radiation and phase control by arranging the first annular units and the second annular units on the structure layer to detect signals of different frequencies, and the alternately coplanar arrangement of the dual-frequency array elements is conducive to realizing high-efficiency dual-frequency response of the antenna, while maintaining a single-layer planar structure, and the cross-band dual-frequency common-aperture composite planar reflector antenna has the advantages of compact structure, low weight and low cost; and the effective aperture of the array element can be fully utilized, which is conducive to realizing low-frequency and high-frequency high-gain high-efficiency radiation performance.

Description

Technical Field

[0001] This invention relates to a radar reflector antenna, and more particularly to a cross-band dual-frequency common-aperture composite planar reflector antenna. Background Technology

[0002] In recent years, with the rapid development of reflector antennas in satellite communications, radar, imaging systems, and other applications, the need for cross-frequency band, same-aperture composite antennas has emerged, replacing traditional multiple antennas with a single antenna. Planar reflector array antennas, with their planar shape, offer advantages such as low thickness, light weight, and ease of installation, making them particularly suitable for small and medium-sized satellite communication applications. However, planar reflector arrays, due to their use of discrete elements for phase compensation, suffer from narrow bandwidth and large element discrete errors, making it difficult to achieve cross-frequency band dual-band or multi-band common-aperture composite antennas.

[0003] On the one hand, existing planar reflector arrays mostly use microstrip array elements with a single resonant mode to form a two-dimensional planar array. The single resonant microstrip array will generate harmonics in the octave band, which will affect the radiation performance in the octave band. Therefore, it is necessary to explore two new radiation elements that have both broadband resonant reflection characteristics and can avoid the interference of octave band harmonics of low-frequency elements on high frequencies.

[0004] On the other hand, for dual-frequency composite arrays spanning multiple frequency bands and with a large frequency division ratio, the different sizes of the low-frequency and high-frequency elements mean that using a consistent element ratio will result in a significant difference in aperture efficiency between the high-frequency and low-frequency arrays, as well as a significant reduction in the gain of the high-frequency array. Therefore, how to rationally design the ratio of high-frequency and low-frequency elements and the arrangement of low-frequency and high-frequency arrays to achieve high-gain and high-efficiency radiation from both low-frequency and high-frequency arrays is a crucial issue for improving the overall gain and efficiency of reflector array antenna design. Summary of the Invention

[0005] The purpose of this invention is to provide a cross-band dual-frequency common-aperture composite planar reflector antenna, which has the advantages of wide operating bandwidth, compact size, small thickness and low cost.

[0006] To achieve the above objectives, the present invention provides a cross-band dual-frequency common-aperture composite planar reflector antenna, comprising:

[0007] A cross-band dual-frequency common-aperture composite planar reflector antenna, the reflector antenna comprising:

[0008] Grounding layer;

[0009] A structural layer is provided with alternating first annular units and second annular units, wherein the diameter of the first annular unit is larger than the diameter of the second annular unit, and the number of second annular units is greater than the number of first annular units.

[0010] An intermediate layer is disposed between the ground layer and the structural layer.

[0011] In this scheme, by setting up arrays of first and second annular units with different diameters on the structural layer, the two annular units with different diameters constitute a dual-frequency response, which has the characteristics of wide operating bandwidth, compact size, small thickness and low cost.

[0012] Preferably, the first annular unit and the second annular unit are respectively provided with openings.

[0013] In this scheme, by setting openings on the first and second annular units respectively, the size of the first and second annular units can be reduced while keeping their inherent frequencies unchanged. This allows for the inclusion of more first and second annular units while keeping the size of the intermediate layer unchanged, thereby improving space utilization and signal gain.

[0014] Preferably, the first annular unit and the second annular unit each have two openings that are opposite each other in the circumferential direction.

[0015] In this scheme, by setting two symmetrical opening structures, the size of the first and second annular units can be further reduced while keeping their inherent frequencies unchanged. This allows for the inclusion of more first and second annular units while keeping the size of the intermediate layer unchanged, thereby improving space utilization and signal gain.

[0016] Preferably, the second annular unit includes two arc rings, and a connecting portion is provided between the two arc rings.

[0017] In this scheme, by setting a connecting part between the two rings of the second ring unit, the structure of the second ring unit is significantly different from that of the first ring unit, thereby reducing the coupling effect between the first and second ring units and improving the gain of the second ring unit. In addition, the connecting part also allows the size of the second ring unit to be further reduced while maintaining its inherent frequency, making the layout of the second and first ring units more compact, improving space utilization, and increasing signal gain.

[0018] Preferably, the ratio of the number of the second annular unit to the number of the first annular unit is 2:1.

[0019] In this scheme, the second ring unit is used to detect high-frequency signals, and the first ring unit is used to detect low-frequency signals. Setting the number of the second ring unit to twice the number of the first ring unit is beneficial to improving the high-frequency gain and reducing the interference of the octave harmonics of the low-frequency unit on the high frequency.

[0020] Preferably, the structural layer is provided with m*n unit groups, each unit group including one first annular unit and two second annular units, the two second annular units being an inner unit and an outer unit respectively, the inner unit being disposed inside the first annular unit and the outer unit being disposed outside the first annular unit.

[0021] In this scheme, the external units are inserted between the array gaps of the first ring unit, occupying the edge area of ​​the first ring unit, while the internal units are set inside the first ring unit. This reduces the overall size and improves space utilization while ensuring signal gain.

[0022] Preferably, the cell phase shift of the first annular cell within the (i, j)th cell group for:

[0023]

[0024]

[0025] x1(i,j)=-D x / 2+(i-1)×a+a / 2

[0026] y1(i,j)=-Dy / 2+(j-1)×a+a / 2

[0027] λ1=c / f1

[0028] i = [1:m]

[0029] j = [1:n]

[0030] Where m and n are the number of elements in the first annular unit along the x and y coordinate directions, a is the element spacing, h is the focal length of the reflection array, Dx and Dy are the dimensions of the entire array surface composed of m*n element groups in the x and y directions, respectively, and λ1 为 The resonant wavelength corresponding to the low-frequency frequency f1, where c is the speed of light in a vacuum.

[0031] Preferably, the cell phase shift of the internal cell within the (i, j)th cell group for:

[0032]

[0033]

[0034] x2(i,j)=-D x / 2+(i-1)×a+a / 2

[0035] y2(i,j)=-Dy / 2+(j-1)×a+a / 2

[0036] λ2=c / f2

[0037] i = [1:m]

[0038] j = [1:n]

[0039] Where m and n are the number of internal units in the x and y coordinate directions, respectively, a is the unit spacing, h is the focal length of the reflection array, Dx and Dy are the dimensions of the entire array surface composed of m*n unit groups in the x and y directions, respectively, λ2 is the resonant wavelength corresponding to the frequency f2, and c is the speed of light in vacuum.

[0040] Preferably, the cell phase shift of the external cell within the (i, j)th cell group for:

[0041]

[0042]

[0043] x3(i,j)=-D x / 2+(i-1)×a+a

[0044] y3(i,j)=-Dy / 2+(j-1)×a+a

[0045] λ2=c / f2

[0046] i = [1:m]

[0047] j = [1:n]

[0048] Where m and n are the number of external elements in the x and y coordinate directions, respectively; a is the element spacing; h is the focal length of the reflection array; Dx and Dy are the dimensions of the entire array surface composed of m*n element groups in the x and y directions, respectively; λ2 is the resonant wavelength corresponding to the low frequency f2; and c is the speed of light in vacuum.

[0049] In this scheme, by arranging the above rules, the planar reflection array can be converted into a spherical wave, while also improving the signal gain of the planar reflection array.

[0050] Preferably, the rotation angle θ(i,j) of the first annular unit, the inner unit, or the outer unit within the (i,j)th unit group is:

[0051]

[0052] x∈[1, 2, 3]

[0053] in, It is the cell phase shift required for the position of the (i, j)th first annular cell, the inner cell, or the outer cell.

[0054] In this scheme, by setting different rotation angles for each unit according to its position, phase compensation is achieved after the angle rotation, thereby improving the signal reception effect.

[0055] In summary, compared with the prior art, the cross-band dual-frequency common-aperture composite planar reflector antenna provided by the present invention has the following beneficial effects:

[0056] The cross-band dual-frequency co-aperture composite planar reflector antenna of this application achieves high frequency division ratio cross-band radiation and phase modulation by setting a first ring element and a second ring element on the structural layer for detecting signals of different frequencies respectively. The alternating coplanar arrangement of the dual-frequency elements is conducive to achieving high-efficiency dual-frequency response of the antenna, while maintaining a single-layer planar structure, which has the advantages of compact structure, low weight and low cost. The parallel design of the first ring element and the second ring element makes full use of the effective aperture of the array surface, which is conducive to achieving high gain and high efficiency radiation performance at both low and high frequencies. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the cross-band dual-frequency common-aperture composite planar reflector antenna structure of this application.

[0058] Figure 2 This is a top view of structural layer 1 of this application.

[0059] Figure 3 This is an exploded view of the first and second annular elements on the structural layer of the reflective antenna of this application.

[0060] Figure 4 This is a schematic diagram of the structure of the first annular unit of this application.

[0061] Figure 5 This is a schematic diagram of the structure of the second annular unit of this application.

[0062] Figure 6 This is the radiation pattern of the antenna as a whole at frequency f1 in the E-plane of this application.

[0063] Figure 7 This is the radiation pattern of the antenna as a whole in the H-plane at frequency f2.

[0064] Explanation of reference numerals in the attached figures:

[0065] Structural layer 1

[0066] First annular unit 11

[0067] Second ring unit 12

[0068] Intermediate layer 2

[0069] Grounding layer 3 Detailed Implementation

[0070] The following will be combined with the appendix in the embodiments of the present invention. Figure 1 ~Attached Figure 7 The technical solutions, structural features, objectives and effects achieved in the embodiments of the present invention will be described in detail.

[0071] It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions. They are only used to facilitate and clarify the purpose of illustrating the embodiments of the present invention, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationship, or adjustments to the size should still fall within the scope of the technical content disclosed in the present invention, provided that they do not affect the effects and objectives that the present invention can produce.

[0072] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only the expressly listed elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0073] like Figure 1 As shown, the present invention provides a cross-band dual-frequency common-aperture composite planar reflector antenna, including a ground layer 3, a structural layer 1 and an intermediate layer 2.

[0074] Grounding layer 3 is made of metal and is used for back grounding of the reflective antenna.

[0075] like Figures 1-3As shown, structural layer 1 has alternating first annular units 11 and second annular units 12. The diameter of the first annular unit 11 is larger than the diameter of the second annular unit 12. The larger diameter of the first annular unit 11 results in a lower inherent frequency, used to receive relatively low-frequency signals. The smaller diameter of the second annular unit 12 results in a higher inherent frequency, used to receive relatively high-frequency signals. The number of second annular units 12 is greater than the number of first annular units 11. Since the gain of high-frequency signals is significantly lower than that of low-frequency signals, a larger number of second annular units 12 is used to enhance high-frequency gain. In this embodiment, the ratio of the number of second annular units 12 to the number of first annular units 11 is 2:1, achieving high gain for both low and high frequencies simultaneously. In other embodiments, the ratio of the number of second annular units 12 or first annular units 11 can be set to other ratios, such as 1.5:1 or 1.8:1. In this embodiment, the design of a 2:1 ratio between the number of the second annular unit 12 and the first annular unit 11 can make full use of the effective aperture of the array, which is beneficial to achieving high gain and high efficiency radiation performance at both low and high frequencies.

[0076] Intermediate layer 2 is disposed between ground layer 3 and structural layer 1. Intermediate layer 2 is made of high-frequency microwave board.

[0077] In this embodiment, as Figure 4 and Figure 5 As shown, the first annular unit 11 and the second annular unit 12 each have two openings, and the two openings are arranged opposite each other. By setting openings on the first annular unit 11 and the second annular unit 12, the size of the first annular unit 11 and the second annular unit 12 can be reduced without changing their natural frequencies. This allows more first annular units 11 and second annular units 12 to be set on the same area of ​​structural layer 1, improving the area utilization of structural layer 1 and increasing the gain of the received signal on structural layer 1 of the same area. The first annular unit 11 and the second annular unit 12 have different ring-like structure sizes and correspondingly different natural frequencies, and both the first annular unit 11 and the second annular unit 12 form a two-dimensional structure array surrounding the center of the array surface. Utilizing the multi-resonance characteristics of the ring-like structure metamaterial unit is beneficial to improving the bandwidth of the overall reflective array antenna. The dual-band use of two different forms of ring-like structures can achieve high frequency division ratio cross-band radiation and phase modulation. The use of alternating coplanar arrangement of dual-frequency arrays is beneficial to achieving efficient dual-frequency response of the antenna, while maintaining a single-layer planar structure, which has the advantages of compact structure, low weight and low cost.

[0078] In other embodiments, only one opening may be provided on the first annular unit 11 and the second annular unit 12.

[0079] In this embodiment, as Figure 4 As shown, the first annular unit 11 includes two arc-shaped rings, with a gap between the ends of each ring to form two openings. Figure 5 As shown, the second annular unit 12 includes two arc rings, each with a gap to form two openings. Furthermore, a connecting portion is provided between the two arc rings. The connecting portion is a straight rod. The two arc rings of the second annular unit 12 are connected via the connecting portion. Since the first annular unit 11 lacks a connecting portion, the structures of the second annular unit 12 and the first annular unit 11 are different, leading to an increased inherent frequency difference between the first annular unit 11 and the second annular unit 12, thus reducing the coupling effect between high-frequency and low-frequency signals.

[0080] In other embodiments, the connecting portion may not be provided on the second annular unit 12, or a connecting portion of other structural form may be provided, such as a curved or diagonal connecting portion.

[0081] In this embodiment, as Figure 3 As shown, the structural layer 1 has m*n unit groups. Each unit group includes a first ring unit 11 and two second ring units 12. The two second ring units 12 are an inner unit and an outer unit, respectively. The inner unit is located inside the first ring unit 11, and the outer unit is located outside the first ring unit 11.

[0082] In other embodiments, the two second annular units 12 may also be completely disposed outside the first annular unit 11, that is, the two second annular units 12 are disposed in the gap between adjacent first annular units 11.

[0083] In other embodiments, the two second annular units 12 may also be completely disposed inside the first annular unit 11, that is, both second annular units 12 are disposed within adjacent first annular units 11.

[0084] Taking an embodiment where the two second annular units 12 are respectively the inner unit and the outer unit, the unit phase shift of the first annular unit 11 in the (i, j)th unit group is as follows: for:

[0085]

[0086]

[0087] x1(i,j)=-D x / 2+(i-1)×a+a / 2

[0088] y1(i,j)=-Dy / 2+(j-1)×a+a / 2

[0089] λ1=c / f1

[0090] i = [1:m]

[0091] j = [1:n]

[0092] Where m and n are the number of units in the first annular unit 11 in the x and y coordinate directions, respectively, a is the unit spacing, h is the focal length of the reflection array, Dx and Dy are the dimensions of the entire array surface composed of m*n unit groups in the x and y directions, respectively, λ1 is the resonant wavelength corresponding to the low frequency f1, and c is the speed of light in vacuum.

[0093] The element phase shift of the internal elements within the (i, j)th element group for:

[0094]

[0095]

[0096] x2(i,j)=-D x / 2+(i-1)×a+a / 2

[0097] y2(i,j)=-Dy / 2+(j-1)×a+a / 2

[0098] λ2=c / f2

[0099] i = [1:m]

[0100] j = [1:n]

[0101] Where m and n are the number of internal units in the x and y coordinate directions, respectively, a is the unit spacing, h is the focal length of the reflection array, Dx and Dy are the dimensions of the entire array surface composed of m*n unit groups in the x and y directions, respectively, λ2 is the resonant wavelength corresponding to the frequency f2, and c is the speed of light in vacuum.

[0102] The element phase shift of the outer element within the (i, j)th element group for:

[0103]

[0104]

[0105] x3(i,j)=-D x / 2+(i-1)×a+a

[0106] y3(i,j)=-Dy / 2+(j-1)×a+a

[0107] λ2=c / f2

[0108] i = [1:m]

[0109] j = [1:n]

[0110] Where m and n are the number of external elements in the x and y coordinate directions, respectively; a is the element spacing; h is the focal length of the reflection array; Dx and Dy are the dimensions of the entire array surface composed of m*n element groups in the x and y directions, respectively; λ2 is the resonant wavelength corresponding to the low frequency f2; and c is the speed of light in vacuum.

[0111] In other embodiments, when only internal units or only external units are provided in the unit group, the unit phase shift of the internal unit or the external unit can be calculated according to the above formula, where only the specific location of the internal unit or the external unit needs to be considered.

[0112] The outer units are positioned between the column gaps of adjacent first annular units 11, occupying the edge region of the first annular unit 11. The center positions of the outer units and the corresponding first annular units 11 differ by a / 2. The centers of the inner units and the corresponding first annular units 11 are concentrically positioned. By staggering the positions of the outer units and the first annular units 11, outer units are positioned in the gaps of the first annular units 11 without increasing the area of ​​the structural layer 1. The outer and inner units are used to receive high-frequency signals. The number of units used to receive high-frequency signals is twice the number of first annular units 11 used to receive low-frequency signals, thereby enhancing the high-frequency signal gain and solving the problem of excessively low high-frequency signal gain.

[0113] The rotation angle θ(i,j) of the first annular unit 11, or the inner or outer unit within the (i,j)th unit group is:

[0114]

[0115] x∈[1, 2, 3]

[0116] in, It is the cell phase shift required to position the (i, j)th first annular cell 11, or an inner cell or an outer cell. Since the positions of each first annular cell 11, each inner cell, and each outer cell are different, there is a phase difference. Phase compensation is achieved by rotating the first annular cell 11, the inner cell, and the outer cell in each cell group around the physical center.

[0117] This embodiment employs a single unit group comprising a first annular unit 11, an inner unit, and an outer unit. By calculating the unit compensation phases of the first annular unit 11, the inner unit, and the outer unit, and then determining the low-frequency and high-frequency unit arrangements based on the corresponding angular rotation relationships, the array's low-frequency and high-frequency position arrangements can be obtained. In this embodiment, the reflective antenna array has 27*27 units with a unit spacing of 5mm, resulting in an overall array size of 150mm*150mm and a reflective array focal length of 150mm.

[0118] This application utilizes the multi-resonance characteristics of the ring-like metamaterial units 11 and 12 to improve the operating bandwidth of the reflector array. The antenna in this embodiment is designed to operate across the K and Ka bands, spanning a second harmonic. The E-plane radiation direction of the antenna is as follows... Figure 6 As shown, the radiation direction of the antenna's H-plane is as follows: Figure 7 As shown, the antenna has a gain of 28.7 dB at low frequency f1, an E-plane beamwidth of 5.6 degrees, and a sidelobe level of less than -18.1 dB. At high frequency f2, the antenna has a gain of 31.4 dB, an E-plane beamwidth of 2.7 degrees, and a sidelobe level of less than -18.1 dB.

[0119] The parallel design of the cross-band dual-frequency composite subarray in this application is general and can be extended to other millimeter-wave frequency bands. It is applicable to dual-frequency composite planar reflector arrays of any size, and is also applicable to single-frequency planar reflector array antennas.

[0120] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A dual-band co-boresight composite planar reflector antenna across frequency ranges, characterized in that, The reflector antenna comprises: a ground layer; a structure layer, the structure layer being provided with first annular units and second annular units arranged alternately, the first annular units having a diameter greater than that of the second annular units, and the number of the second annular units being greater than that of the first annular units; the ratio of the number of the second annular units to that of the first annular units being 2:1, the structure layer being provided with m*n unit groups, each of the unit groups comprising one first annular unit and two second annular units, the two second annular units being an inner unit and an outer unit respectively, the inner unit being arranged on the inner side of the first annular unit, and the outer unit being arranged on the outer side of the first annular unit; an intermediate layer, the intermediate layer being arranged between the ground layer and the structure layer.

2. The dual-band, co-axial, planar composite reflector antenna across frequency range according to claim 1, wherein, The first annular units and the second annular units are respectively provided with openings.

3. The dual-band, co-axial, planar composite reflector antenna across frequency range according to claim 2, wherein, The first annular units and the second annular units are respectively provided with two openings opposite in the circumferential direction.

4. The dual-band, co-axial, planar composite reflector antenna across frequency range according to claim 3, wherein, The second annular units comprise two arc rings, and the two arc rings are provided with a connecting portion.

5. The cross-frequency dual-frequency co-baffled compound planar reflector antenna of claim 1, wherein, an amount of cell phase shift of the first ring-shaped cell within the (i, j)th cell group is: x1(i,j) = -D x / 2+(i-1)×a+a / 2 y1(i,j) = -Dy / 2 + (j-1) × a + a / 2 λ1 = c / f1 i = [1:m] j = [1:n] where m and n are the number of unit cells in the x and y coordinate directions, respectively, a is the unit cell spacing, h is the focal length of the reflective array, D x and D y are the dimensions of the entire array in the x and y directions, respectively, composed of m*n unit cells, λ1is the resonant wavelength corresponding to the frequency f1, and c is the speed of light in vacuum.

6. The cross-frequency dual-frequency co-baffled compound planar reflector antenna of Claim 1 wherein, the cell phase shift amount of the inner cell within the (i, j)th cell group is: x2(i,j) = -D x / 2+(i-1)×a+a / 2 y2(i,j) = -Dy / 2 + (j-1) × a + a / 2 λ2 = c / f2 i = [1:m] j = [1:n] where m and n are the number of unit cells in the x and y coordinate directions, respectively, a is the unit cell spacing, h is the focal length of the reflective array, D x and D y are the dimensions of the entire array in the x and y directions, respectively, composed of m*n unit cells, and λ2is the resonant wavelength corresponding to the frequency f2, and c is the speed of light in vacuum.

7. The cross-frequency dual-frequency co-baffled compound planar reflector antenna of claim 1, wherein, a cell phase shift amount of the outer cell within the (i, j)th cell group is: x3(i,j) = -D x / 2 + (i-1) x a + a y3(i,j) = -Dy / 2 + (j-1) × a + a λ2 = c / f2 i = [1:m] j = [1:n] where m and n are the number of cells in x and y coordinate directions, a is the cell pitch, h is the focal length of the reflective array, D x and D y are the size of the entire array in x and y directions, respectively, composed of m*n cells, and λ2is the resonant wavelength corresponding to the frequency f2, and c is the speed of light in vacuum.

8. The cross-frequency dual-frequency co-baffled compound planar reflector antenna of any of claims 5-7, wherein, The rotation angle θ(i,j) of the first annular unit, the inner unit or the outer unit in the (i,j)th unit group is: x∈[1,2,3] wherein is the amount of cell phase shift required for the (i,j)th said first annular cell or said inner cell or said outer cell location.

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