Low-profile single-layer dual-polarization structure composite array antenna for C / K wave band

Abstract

The invention belongs to the technical field of antennas, and particularly relates to a low-profile single-layer dual-polarization structure composite array antenna for a C / K wave band. Comprising a dielectric substrate, the lower surface of the dielectric substrate is a metal floor, and m * m composite array elements are integrated on the upper surface; each composite array element comprises a square ring structure and a Jerusalem cross structure arranged in the square ring structure, and the Jerusalem cross structure and the square ring structure are not in contact and coincide in center; all the square ring structures form a C-band array antenna, super units are divided according to n * n, and each super unit is fed through an SMA coaxial line; all the Jerusalem cross structures form a k-band reflective array antenna, super units are divided according to z * z, and each super unit is connected with a horn antenna through a waveguide for coupling radiation; wherein: nlt; zlt, zlt; m, z and n are positive numbers. According to the invention, multiplexing of a C / K wave band antenna structure is realized by using the single-layer dielectric substrate, the height is reduced, the process is simplified, the cost is reduced, the antenna is suitable for a multi-frequency satellite communication system, and large-scale array arrangement can provide high-gain radiation.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a low-profile single-layer dual-polarization structure composite array antenna for C / K bands. Background Art

[0002] With the development of spectrum resources and the progress of communication technologies, an increasing number of frequency bands are being put into use in satellite communication systems, and each frequency band plays a different role with its unique advantages. Taking C-band communication as an example, the characteristic of its long wavelength gives it stronger rain attenuation resistance, so it has been widely applied and studied in fields such as full-time satellite TV networks and original satellite feeds. However, due to the relatively low communication frequency of the C-band, its transmission rate is usually limited. Increasing the communication carrier frequency is the main way to improve the transmission rate. The K-band satellite communication frequency band is a typical representative and is widely used in inter-satellite communication, such as data transmission between the International Space Station and the Space Shuttle. To achieve the flexibility of satellite communication systems, communication systems often need to support dual-frequency communication in both the C-band and the K-band. The traditional method uses two sets of antennas with different frequencies, but this will greatly increase the system complexity and cost. For this reason, scholars have proposed a solution of a structure composite array antenna. This kind of antenna integrates antennas of two or more frequency bands into the same structure. By reasonable design and suppression of the mutual coupling between antennas, it not only helps to reduce the size of the antenna, but also simplifies the multi-frequency communication system and reduces costs.

[0003] For example, a dual-frequency dual-circular polarization antenna disclosed in the Chinese patent application with the publication number CN118336375A uses the structure of a Fabry-Perot resonator to achieve high gain of the array antenna, which can meet the frequency division duplex communication requirements of satellite communication and has the characteristics of low cost and simple processing. Another example is a dual-frequency dual-circular polarization millimeter-wave array antenna disclosed in the Chinese patent application with the publication number CN117810686A. This antenna uses a multi-layer PCB structure to achieve a high degree of integration of the radiation structure and has the advantages of low loss, ultra-wideband, and low side lobes. These two dual-frequency common-aperture antenna arrays effectively reduce the overall size of the antenna through careful adjustment of the antenna structure. However, both of these antennas use multi-layer substrates. The increase in the number of substrate layers has caused a sharp rise in processing costs, and the relatively high profile height has increased the overall weight of the antenna. Therefore, there is still a large room for improvement. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-profile single-layer dual-polarization structure composite array antenna for C / K bands to solve the problems of complex processing technology and rising costs caused by the high profile height and multi-layer substrate structure existing in the above-mentioned existing dual-frequency common-aperture antenna arrays.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A low-profile single-layer dual-polarized composite array antenna for C / K band, comprising a dielectric substrate. The lower surface of the dielectric substrate is a metal floor, and m×m composite array elements are integrated on the upper surface; each composite array element includes a square loop structure and a Jerusalem cross structure placed inside it. The Jerusalem cross structure and the square loop structure do not contact each other and their centers coincide; all the square loop structures form a C-band array antenna, which is divided into supercells by n×n. Each supercell is fed by two SMA coaxial cables in orthogonal directions; all the Jerusalem cross structures form a k-band reflectarray antenna, which is divided into supercells by z×z. Each supercell is coupled and radiated through a waveguide connected to a horn antenna; where: n < z < m, and both z and n are positive numbers.

[0007] Furthermore, the Jerusalem cross structure is composed of main arms in a cross structure. Four ends of the main arms are vertically connected to sub-arms, and the length of the main arms is much greater than the length of the sub-arms, and the width of the main arms is equal to the width of the sub-arms. By introducing the sub-arms and setting the length of the main arms much greater than the length of the sub-arms, the size area of the Jerusalem cross structure as a reflectarray unit is effectively reduced, so that the unit obtains more reflection phase shifts.

[0008] Furthermore, the SMA coaxial cable is located below the dielectric substrate. The inner conductor of its inner conductor passes through the substrate and is connected to the C-band supercell, and the outer conductor is connected to the metal layer on the dielectric substrate to achieve grounding.

[0009] Furthermore, in the k-band reflectarray antenna, the size of the main arms of the Jerusalem cross structure is adjusted according to requirements to achieve independent phase control under x- and y-line polarization incidence.

[0010] After adopting the above technical solutions, the present invention has the following advantages:

[0011] 1. As a device for C-band and K-band energy radiation, by sharing the same layer of radiation structure for the C-band array antenna and the K-band reflectarray antenna, the present invention can achieve the structural reuse of the C / K-band antenna with only a single-layer dielectric substrate, greatly reducing the profile height of the antenna, simplifying the processing technology, and reducing the processing cost;

[0012] 2. The composite array element of the present invention is composed of a square loop and a Jerusalem cross structure placed inside it, with a simple structure and easy to process; the size of the Jerusalem cross is adjusted according to the usage requirements during design, which can provide the required phase shift for the reflectarray antenna and has stronger flexibility.

[0013] 3. In the overall structure of the present invention, all the square ring structures form a C-band array antenna, and all the Jerusalem cross structures form a K-band reflectarray antenna. Radiation ports with x and y polarizations are placed in the C-band radiation antenna elements; by controlling the lengths of the two arms of the K-band reflectarray antenna elements, the reflection phase shifts in the x polarization and y polarization can be obtained respectively. Thus, the present invention has the radiation characteristics of dual-band and dual-polarization, and has a stronger communication ability; therefore, it is applicable to multi-frequency satellite communication systems and can provide high-gain radiation for them. Description of the Drawings

[0014] Figure 1 Schematic diagram of the structure of each element in the low-profile single-layer dual-polarization structure composite array antenna of the embodiment;

[0015] Figure 2 Schematic diagram of dividing the supercell of the C-band array antenna of the embodiment;

[0016] Figure 3 Side view of the C-band array antenna element of the embodiment;

[0017] Figure 4 Schematic diagram of the overall structure of the array surface of the low-profile single-layer dual-polarization structure composite array antenna of the embodiment;

[0018] Figure 5 Simulation curve of the amplitude and phase response of the reflectarray antenna supercell of the embodiment;

[0019] Figure 6 Simulation curve of the S-parameters of the C-band array antenna supercell of the embodiment;

[0020] Figure 7 Simulated radiation pattern of the K-band reflectarray antenna in the X polarization of the embodiment;

[0021] Figure 8 Simulated radiation pattern of the K-band reflectarray antenna in the Y polarization of the embodiment;

[0022] Figure 9 Simulated radiation pattern of the C-band array antenna in the X polarization of the embodiment;

[0023] Figure 10 Simulated radiation pattern of the C-band array antenna in the Y polarization of the embodiment;

[0024] Reference Signs:

[0025] 1 is the square ring structure, 2 is the Jerusalem cross structure, 3 is the x-polarization feeding port of the C-band antenna element, 4 is the y-polarization feeding port of the C-band antenna element, 5 is the dielectric substrate, 6 is the SMA coaxial cable, and 7 is the reflectarray antenna. Detailed Description of the Invention

[0026] The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments.

[0027] As Figures 1 - 4 shown, a low-profile single-layer dual-polarized composite array antenna for C / K band provided in this embodiment includes a dielectric substrate 5. The lower surface of the dielectric substrate 5 is a metal floor, and m×m composite array elements are integrated on the upper surface. Each composite array element includes a square loop structure 1 and a Jerusalem cross structure 2 placed inside it. The Jerusalem cross structure 2 and the square loop structure 4 do not contact each other and their centers coincide. All the square loop structures 4 form a C-band array antenna, which is divided into supercells according to n×n. Each supercell is fed by two SMA coaxial lines 6 in orthogonal directions to achieve dual-polarization characteristics. All the Jerusalem cross structures form a k-band reflectarray antenna 7, which is divided into supercells according to z×z. Each supercell is coupled and radiated through a waveguide-connected horn antenna.

[0028] The Jerusalem cross structure is composed of main arms in a cross structure. Four ends of the main arms are vertically connected to the sub-arms, and the length of the main arms is much greater than that of the sub-arms. The width of the main arms is equal to the width of the sub-arms. The SMA coaxial line is located below the dielectric substrate. The inner conductor of its inner conductor passes through the substrate and is connected to the c-band supercell, and the outer conductor is connected to the metal layer on the dielectric substrate to achieve grounding. In the k-band reflectarray antenna, the lengths R x and R y of the two main arms of the Jerusalem cross structure are adjusted according to requirements to achieve independent phase control under x and y linear polarization incidence. And because this structure is cross-symmetric, R x and R y have consistent amplitude-phase responses.

[0029] In this embodiment, the material of the dielectric substrate is RF-35, the dielectric constant is 3.5, the loss tangent is 0.0018, and the thickness is 1.524 mm. The working frequency band that the C-band array antenna can achieve is 5.15 to 5.35 GHz. Its supercells are divided according to 3×3, and there are a total of 6×6 supercells. The working frequency band that the k-band reflectarray antenna can achieve is 18.87 to 22.47 GHz. The profile height at 5.25 GHz is 0.027 vacuum wavelengths when divided into supercells according to 20×20. The final antenna array surface is composed of 20×20 minimum units. When working at 5.25 GHz, the radiation gain of x polarization is 13.81 dBi, and the radiation gain of y polarization is 11.54 dBi; when working at 20 GHz, the radiation gain of x polarization is 25.6 dBi, and the radiation gain of y polarization is 25.7 dBi.

[0030] Figure 5 are the simulation curves of the element amplitude and phase responses of the reflectarray antenna supercell in the embodiment; as Figure 5 can be seen, when Rx When it increases from 2.0 mm to 4.5 mm, the phase shift decreases by 301°, and the return loss is within -0.2 dB.

[0031] Figure 6 It is the simulation curve of the S parameters of the supercell of the C-band array antenna in the embodiment; from Figure 6 it can be seen that the frequency range where S11 is less than -10 dB is from 5.08 to 5.32 GHz.

[0032] Figure 7 It is the simulated radiation pattern of the X polarization of the K-band reflectarray antenna in the embodiment; from Figure 7 it can be seen that the normal radiation gains of the co-polarization in the E-plane and the H-plane are 25.63 dBi, and the corresponding aperture efficiency is 44.7%. By comparing the co-polarization radiation patterns and the cross-polarization radiation patterns in the E / H planes, the cross-polarization suppression ratio is greater than 20 dB.

[0033] Figure 8 It is the simulated radiation pattern of the Y polarization of the K-band reflectarray antenna in the embodiment; from Figure 8 it can be seen that the normal radiation gains of the co-polarization in the E-plane and the H-plane are 25.69 dBi, and the corresponding aperture efficiency is 45.33%. By comparing the co-polarization radiation patterns and the cross-polarization radiation patterns in the E / H planes, the cross-polarization suppression ratio is greater than 28 dB.

[0034] Figure 9 It is the simulated radiation pattern of the X polarization of the C-band array antenna in the embodiment; from Figure 9 it can be seen that the normal radiation gains of the co-polarization in the E-plane and the H-plane are 13.81 dBi. By comparing the co-polarization radiation patterns and the cross-polarization radiation patterns in the E / H planes, the cross-polarization suppression ratio exceeds 25 dB.

[0035] Figure 10 It is the simulated radiation pattern of the Y polarization of the C-band array antenna in the embodiment; from Figure 10 it can be seen that the normal radiation gains of the co-polarization in the E-plane and the H-plane are 11.54 dBi. By comparing the co-polarization radiation patterns and the cross-polarization radiation patterns in the E / H planes, the cross-polarization suppression ratio exceeds 13 dB.

[0036] In summary, the antenna involved in this embodiment only requires a single-layer dielectric substrate to realize the multiplexing of the C / K-band antenna structures. This design greatly reduces the profile height of the antenna, simplifies the processing technology, and cuts the processing cost. Its composite element consists of a square ring and a Jerusalem cross structure placed inside the ring, with a simple overall structure and low processing difficulty. It not only has the radiation characteristics of dual-band and dual-polarization, but also has stronger communication capabilities; thus, it is suitable for multi-frequency satellite communication systems and can provide high-gain radiation for them.

[0037] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A low-profile single-layer dual-polarized composite array antenna for C / K band, comprising a dielectric substrate, characterized in that The lower surface of the dielectric substrate is a metal floor, and the upper surface integrates m×m composite array elements; each composite array element includes a square ring structure and a Jerusalem cross structure placed inside it. The Jerusalem cross structure does not contact the square ring structure and their centers coincide; all the square ring structures form a C-band array antenna, which is divided into supercells by n×n. Each supercell is fed by two SMA coaxial cables in orthogonal directions; All the Jerusalem cross structures form a k-band reflectarray antenna, which is divided into supercells by z×z. Each supercell is coupled and radiated through a waveguide connected to a horn antenna; where: n < z < m, and both z and n are positive numbers.

2. The low-profile single-layer dual-polarized composite array antenna for C / K band according to claim 1, wherein The Jerusalem cross structure is composed of main arms in a cross structure. Four ends of the main arms are vertically connected to the sub-arms, and the length of the main arms is much greater than that of the sub-arms, and the width of the main arms is equal to the width of the sub-arms.

3. A low-profile single-layer dual-polarized composite array antenna for C / K band according to claim 1, characterized in that, The SMA coaxial cable is located below the dielectric substrate. The inner conductor of its inner conductor passes through the substrate and is connected to the C-band supercell, and the outer conductor is connected to the metal layer on the dielectric substrate to achieve grounding.

4. A low-profile single-layer dual-polarized composite array antenna for C / K band according to claim 1, characterized in that In the k-band reflectarray antenna, the size of the main arms of the Jerusalem cross structure is adjusted according to requirements to achieve independent phase control under x- and y-line polarization incidence.

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