Multilayer folding transmission unit and array system

Abstract

The invention relates to a multilayer folding transmission unit and an array system, and belongs to the technical field of antennas. Comprising a folding dielectric plate and metal patches, a polyimide film printed with the metal patches is sequentially folded in a Z shape in the vertical direction to form an integrated structure composed of four planes and three connecting slopes, the height between every two adjacent planes is h, and the metal patches are located on the upper surfaces of the four planes respectively. Each group of metal patches consists of two concentric square rings; the side length of each outer-circle square ring is L1, the side length of each inner-circle square ring is 0.6 times of L1, the widths W of the two square rings are equal, the movement range of the multi-layer folding transmission unit is larger than 360 degrees by adjusting L1, and the transmission amplitude loss is smaller than 2dB. Therefore, the multi-layer folding transmission array achieves a good broadband effect on the premise of low profile and low cost.

Description

Technical Field

[0001] The present invention relates to a multi-layer folded transmission unit and an array system, belonging to the technical field of antennas. Background Art

[0002] In advanced wireless systems, high-gain antennas are an important part of microwave, millimeter-wave, and sub-millimeter-wave communication and sensing systems. Traditional high-gain antennas mainly include array antennas and large-aperture antennas such as reflectarray antennas. The new transmission phase-shift surface array inherits the characteristics of traditional reflectarray antennas and array antennas respectively, and makes complementary advantages, and has great potential in terms of structure, volume, weight, cost, beam control, etc. In future millimeter-wave terahertz communication, spaceborne applications, vehicle conformal applications, etc., the transmission array will play an important role. The transmission array antenna is essentially an artificial electromagnetic material. Under the requirements of both meeting the transmission phase and the transmission amplitude, it is crucial to improve the bandwidth. Adopting a multi-layer thin-film structure is one of the important ways to broaden the bandwidth. Therefore, it is of great significance to deeply study the characteristics of the multi-layer thin-film transmission surface. At present, the multi-layer transmission array is processed layer by layer, with high cost and the bandwidth needs to be further improved. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a multi-layer folded transmission unit and an array system.

[0004] To achieve the above purpose, the technical solution of the present invention is as follows.

[0005] A multi-layer folded transmission unit includes a folded dielectric plate and metal patches. It is an integral structure composed of four planes and three connecting inclined planes formed by folding a polyimide film printed with metal patches in a Z shape along the vertical direction. The height between adjacent two planes is h. The metal patches are respectively located on the upper surfaces of the four planes. Each group of metal patches is composed of two concentric square rings; the side length of the outer square ring is L1, the side length of the inner square ring is 0.6 times L1, and the width W of the two square rings is equal. By adjusting L1, the phase shift range of the multi-layer folded transmission unit is greater than 360 degrees, and the transmission amplitude loss is less than 2 dB.

[0006] Further, the side length of the plane is 8 - 9 mm, h is 3 - 4 mm, L1 is 5.3 - 7.8 mm, and W is 0.3 - 0.4 mm. More specifically, the side length of the plane is 8.325 mm, h is 3.75 mm, and W is 0.315 mm.

[0007] Further, the dielectric constant of the polyimide film is 3.5.

[0008] Further, the thickness of the polyimide film is 0.375 mm.

[0009] Further, the material of the metal patch is copper.

[0010] Further, the metal patch is printed on a polyimide film.

[0011] A multi-layer folded transmissive array system includes a multi-layer folded transmissive array and a feed horn. The multi-layer folded transmissive array is formed by repeatedly folding a polyimide film in the form of multi-layer folded transmissive units, and two adjacent multi-layer folded transmissive units are in an axisymmetric structure; the feed horn is located directly above the multi-layer folded transmissive array and is used to emit a symmetric electromagnetic wave beam to the multi-layer folded transmissive array.

[0012] Further, the phase compensation of the multi-layer folded transmissive units in the multi-layer folded transmissive array is:

[0013] where represents the position of the th multi-layer folded transmissive unit in the Cartesian coordinate system, and represent the beam direction of the transmitted wave generated by the multi-layer folded transmissive array, represents the distance between the th multi-layer folded transmissive unit and the phase center of the horn, represents the wave number of the electromagnetic wave propagation.

[0014] Further, the center frequency of the feed horn is 16 GHz, the waveguide aperture size is 16 mm × 14.29 mm, the waveguide length is 15.88 mm, the horn aperture size is 28.58 mm × 22.23 mm, and the horn length is 47.63 mm.

[0015] Advantageous Effects The present invention provides a multi-layer folded transmissive unit, which uses a polyimide film printed with metal and is folded to form a four-layer transmissive array; by adjusting the size of the metal patch, the phase shift range and transmission amplitude of the multi-layer folded transmissive unit are adjusted, and a multi-layer folded transmissive unit with a phase shift range greater than 360 degrees and a transmission amplitude loss less than 2 dB is obtained, so that the multi-layer folded transmissive array achieves a good broadband effect on the premise of low profile and low cost.

[0016] The present invention provides a multi-layer folded transmissive array system, which uses a flexible polyimide material and uses a four-layer structure formed by folding. The layers are supported by the inclined plane of the polyimide film folded out between the layers. A single polyimide film can be used to realize a multi-layer array, which simplifies the processing and manufacturing method. The polyimide film array is easy to process, has a low cost, and is light in weight. Description of the Drawings

[0017] Figure 1 This is the top view of the multi-layer folded transmission unit of the present invention.

[0018] Figure 2 This is the structural diagram of the multi-layer folded transmission unit of the present invention.

[0019] Figure 3 This is the overall structural diagram of the multi-layer folded transmission array system of the present invention.

[0020] Figure 4 This is the folding schematic diagram of the multi-layer folded transmission array of the present invention.

[0021] Figure 5 This is the structural diagram of the feed horn of the present invention.

[0022] Figure 6 This is the amplitude-phase distribution diagram of the multi-layer folded transmission unit in Embodiment 1.

[0023] Figure 7 This is the reflection coefficient diagram of the feed horn in Embodiment 1.

[0024] Figure 8 This is the radiation pattern of the feed horn in Embodiment 1.

[0025] Figure 9 This is the phase distribution diagram of the multi-layer folded transmission array in Embodiment 1.

[0026] Figure 10 This is the far-field gain diagram of the multi-layer folded transmission array system in Embodiment 1.

[0027] Figure 11 This is the 1dB far-field gain diagram of the multi-layer folded transmission array system in Embodiment 1. Detailed implementation manners

[0028] The present invention will be further described in detail below in conjunction with specific embodiments.

[0029] As Figure 1-2 shown, a multi-layer folded transmission unit includes a folded dielectric plate and metal patches. It is an integrated structure composed of four planes and three connecting inclined planes formed by folding a polyimide film printed with metal patches in a Z shape along the vertical direction. The height between adjacent two planes is h. The metal patches are respectively located on the upper surfaces of the four planes. Each group of metal patches is composed of two concentric square rings. The side length of the outer square ring is L1, the side length of the inner square ring is 0.6 times L1, and the width W of the two square rings is equal. By adjusting L1, the phase shift range of the multi-layer folded transmission unit is greater than 360 degrees, and the transmission amplitude loss is less than 2 dB.

[0030] In some embodiments, the side length of the plane is 8 - 9 mm, h is 3 - 4 mm, L1 is 5.3 - 7.8 mm, and W is 0.3 - 0.4 mm.

[0031] As Figure 3-5 shown, a multi - layer folded transmission array system includes a multi - layer folded transmission array and a feed horn. The multi - layer folded transmission array is repeatedly folded from a polyimide film in the form of multi - layer folded transmission units, and two adjacent multi - layer folded transmission units are axisymmetric structures; the feed horn is located directly above the multi - layer folded transmission array and is used to emit symmetric electromagnetic beams to the multi - layer folded transmission array.

[0032] Furthermore, the phase compensation of the multi - layer folded transmission units in the multi - layer folded transmission array is:

[0033] where represents the position of the th multi - layer folded transmission unit in the Cartesian coordinate system, and represent the beam direction of the transmitted wave generated by the multi - layer folded transmission array, represents the distance between the th multi - layer folded transmission unit and the phase center of the horn, represents the wave number of the electromagnetic wave propagation.

[0034] Embodiment 1 In this embodiment, the side length of the square plane is 8.325 mm, h is 3.75 mm, the length of the inclined plane is 8.93 mm, the angle between the inclined plane and the square plane is 24.6 degrees, W is 0.315 mm, and L1 is 5.3 - 7.8 mm. The dielectric constant of the polyimide film is 3.5 and the thickness is 0.375 mm. The material of the metal patch is copper. The metal patch is printed on the polyimide film.

[0035] In this embodiment, the scale of the multi - layer folded transmission array is 10×10 multi - layer folded transmission units. The center frequency of the feed horn is 16 GHz. The waveguide aperture size is 16 mm×14.29 mm, the waveguide length is 15.88 mm, the horn aperture size is 28.58 mm×22.23 mm, and the horn length is 47.63 mm. The feed horn is fed with normal incidence, ensuring the symmetry of the incident wave.

[0036] Figure 6 This is the amplitude - phase distribution diagram of the multi - layer folded transmission unit in this embodiment. The transmission amplitude loss of the multi - layer folded transmission unit is less than 2 dB, and the phase shift range of the multi - layer folded transmission unit reaches 596 degrees, meeting the phase requirement of more than 360 degrees.

[0037] Figure 7 This is the reflection coefficient diagram of the feed horn in this embodiment. The reflection coefficient of the feed horn is always maintained below -15dB. This result confirms that the horn antenna has excellent matching performance and high radiation efficiency.

[0038] Figure 8 This is the feed horn pattern for this embodiment. The feed horn achieves a peak gain of 12dB, and its -10dB beamwidth is approximately 80 degrees. Within an observation angle of -45 to 45 degrees, the antenna's E- and H-plane radiation patterns are highly consistent, demonstrating excellent rotational symmetry. Based on these characteristics, this feed horn meets the design requirements for transmission array antenna sources. Its E- and H-plane radiation patterns are highly stable, with low spillover loss and high aperture efficiency.

[0039] As an indirect space-fed array system, the multi-layer folded transmission array is also suitable for performance analysis based on traditional array antenna theory. The spacing between the multi-layer folded transmission units plays a crucial role in the performance of the entire multi-layer folded transmission array. If the spacing is too small, the coupling between the multi-layer folded transmission units will be enhanced, which may interfere with the impedance matching of each multi-layer folded transmission unit, thereby reducing the overall efficiency of the multi-layer folded transmission array. On the contrary, if the spacing is too large, it may cause a grating lobe effect, reduce the energy concentration of the main radiation, and thus lead to a reduction in radiation gain. Therefore, when designing the size of the multi-layer folded transmission array, the spacing between the multi-layer folded transmission units must be carefully considered to minimize the coupling effect and the generation of grating lobes between the multi-layer folded transmission units. To avoid the generation of grating lobes, the spacing d between the multi-layer folded transmission units is designed using the following formula: ; is defined as the larger of the incident wave angle and the tilt angle of the antenna beam, is the wavelength.

[0040] The spacing between the multi-layer folded transmission units is designed to be 8.325mm×8.325mm, which is approximately 0.44 times the wavelength.

[0041] When designing a multi-layer folded transmission array, first calculate the distance between the units at different positions on the multi-layer folded transmission array and the phase center of the feed source, and obtain the compensation phase value that each unit should provide. Then, convert the compensation phase of each unit to the corresponding L1 length of the unit. The spherical wave emitted from the feed source is phase-modulated by each unit on the transmission array surface to complete the secondary emission, and converge into a high-gain pencil beam in the far field to achieve high-gain transmission. There are the following relationships:

[0042] Among them, represents the position of the th multi-layer folded transmission unit in the Cartesian coordinate system, and represent the beam direction of the transmitted wave generated by the multi-layer folded transmission array, represents the th distance between the multi-layer folded transmission unit and the horn phase center, represents the wave number of the electromagnetic wave propagation.

[0043] After calculation and normalization, the phase distribution of the units on the transmission array surface is as Figure 9 shown, and the phase distribution is maintained between 0 degrees and 360 degrees.

[0044] After setting the far-field conditions, the multi-layer folded transmission array system is simulated, and the far-field gain pattern as Figure 10 shown is obtained. The maximum gain is about 21 dB. The center frequency at which the multi-layer folded transmission array system operates is 16 GHz, the 3 dB gain operating frequency is from 14 GHz to 17.25 GHz, and the 3 dB relative bandwidth is 20.3%. The 1 dB gain operating frequency of the multi-layer folded transmission array system is 14.9 GHz to 16.8 GHz, and the 1 dB relative bandwidth is 11.87%, as Figure 11 shown.

[0045] In summary, the invention includes but is not limited to the above embodiments. Any equivalent replacement or partial improvement made under the spirit and principle of the present invention will be regarded as within the protection scope of the present invention.

Claims

1. A multi-layer folding transmission unit, characterized in that: It includes a folded dielectric plate and metal patches. It is an integral structure composed of four planes and three connecting inclined planes formed by folding a polyimide film printed with metal patches in a Z shape along the vertical direction. The height between adjacent two planes is h. The metal patches are respectively located on the upper surfaces of the four planes. Each group of metal patches consists of two concentric square rings. The side length of the outer square ring is L1, the side length of the inner square ring is 0.6 times L1, and the width W of the two square rings is equal. By adjusting L1, the shift range of the multi-layer folded transmission unit is greater than 360 degrees, and the transmission amplitude loss is less than 2 dB.

2. The multi-layer folding transmission unit according to claim 1, wherein: The side length of the plane is 8 - 9 mm, h is 3 - 4 mm, L1 is 5.3 - 7.8 mm, and W is 0.3 - 0.4 mm.

3. The multi-layer folding transmission unit according to claim 2, characterized in that The side length of the plane is 8.325 mm, h is 3.75 mm, and W is 0.315 mm.

4. A multi-layer folding transmission unit according to claim 1, characterized in that The dielectric constant of the polyimide film is 3.

5.

5. A multi-layer folding transmission unit according to claim 1 or 4, characterized in that The thickness of the polyimide film is 0.375 mm.

6. The multi-layer folding transmission unit according to claim 1, characterized in that The material of the metal patches is copper.

7. A multi-layer folding transmission unit according to claim 1 or 6, characterized in that The metal patches are printed on the polyimide film.

8. A multi-layer folded transmissive array system, characterized in that: It includes a multi-layer folded transmission array and a feed horn. The multi-layer folded transmission array is formed by repeatedly folding a polyimide film in the form of the multi-layer folded transmission unit described in any one of claims 1 - 7. Adjacent two multi-layer folded transmission units are axisymmetric structures. The feed horn is located directly above the multi-layer folded transmission array and is used to emit a symmetric electromagnetic wave beam to the multi-layer folded transmission array.

9. The multi-layer folded transmission array system according to claim 8, wherein: Phase compensation of the multi-layer folded transmission units in the multi-layer folded transmission array is as follows: Among them, represents the position of the th multi-layer folded transmission unit in the Cartesian coordinate system, and represents the beam direction of the transmitted wave generated by the multi-layer folded transmission array, represents the th distance between the multi-layer folded transmission unit and the horn phase center, represents the wave number of the electromagnetic wave propagation.

10. A multi-layer folded transmission array system as claimed in claim 8, wherein The center frequency of the feed horn is 16 GHz, the waveguide aperture size is 16 mm × 14.29 mm, the waveguide length is 15.88 mm, the horn aperture size is 28.58 mm × 22.23 mm, and the horn length is 47.63 mm.

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