Four-arm helical antenna phased array

Abstract

The invention belongs to the technical field of antennas, and relates to a four-arm helical antenna phased array, which is realized by using a low-temperature co-fired ceramic process, and comprises a plurality of antenna array elements, the plurality of antenna array elements are arranged in a rectangular array mode, and each antenna array element comprises an input coaxial structure, an antenna feed network structure and an antenna radiation structure, the input coaxial structure receives an external coaxial feed signal and transmits the external coaxial feed signal to the antenna feed network structure, the antenna feed network structure divides an input signal into four paths of circularly polarized output with the difference of 90 degrees, and the antenna radiation structure receives the circularly polarized output and generates circularly polarized radiation. Through combination of innovative designs such as a chain type structure, sequential rotation feeding, short circuit terminal optimization and an isolation assembly, the requirements of miniaturization and high integration level are met, the circular polarization characteristic and array expandability are improved, inter-unit coupling and array complexity can be reduced, and the antenna performance is improved. And the stable performance and the manufacturing consistency of the large array under the conditions of broadband and high scanning angle are ensured.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, specifically relating to a four-arm spiral antenna phased array. Background Technology

[0002] With the rapid development of satellite communications, millimeter-wave radar, and next-generation mobile communications (5G / 6G), the Ka band has gradually become a focus of research and application due to its abundant spectrum resources, large bandwidth, and high capacity. Within this band, antenna systems not only need to possess broadband characteristics, good circular polarization performance, and high gain, but also need to be able to easily achieve arraying and beam scanning to meet the demands of high speed, large capacity, and anti-interference.

[0003] Currently, research on Ka-band phased array antennas mainly focuses on microstrip patch antennas, slot antennas, and dielectric resonator antennas. These antennas offer advantages in terms of compact structure, ease of planar fabrication, and arraying, but they generally suffer from limited bandwidth, insufficient circular polarization performance, or high dependence on fabrication precision, thus limiting their application in high-performance satellite communications and broadband millimeter-wave systems. In contrast, quad-helical antennas naturally achieve good circular polarization characteristics and a wider operating bandwidth, and are therefore widely used in mid-to-low frequency bands (such as L, S, C, and X bands).

[0004] However, the application of quad-helical antennas remains relatively limited in the higher Ka-band. This is mainly because traditional structures often employ metal wire or printing processes, separating the radiating element from the feed network. The precision of manufacturing and assembly is difficult to guarantee under high-frequency conditions, easily leading to decreased impedance matching and circular polarization performance. Simultaneously, to achieve ideal radiation characteristics, helical antennas in the Ka-band still need to maintain a certain size, which is detrimental to compact design and integration with phased array systems. Furthermore, the coupling error between the feed network and the radiating element is more pronounced in the millimeter-wave band, and even slight deviations in manufacturing processes can cause performance instability, further restricting their widespread adoption in array applications. Therefore, providing a quad-helical antenna in the Ka-band that is compact, reliably manufactured, stable in performance, and easily mass-producible has become a pressing technical problem to be solved in this field. Summary of the Invention

[0005] In view of this, the present invention provides a four-arm helical antenna phased array to solve the above-mentioned technical problems.

[0006] The technical solution of this invention is: A four-arm spiral antenna phased array, realized using a low-temperature co-fired ceramic process, includes multiple antenna elements arranged in a rectangular array with adjacent elements in contact. Each antenna element includes: Input coaxial structure; The antenna feed network structure includes a feed dielectric layer and a first T-type power divider, a second T-type power divider, and a third T-type power divider disposed in the feed dielectric layer. The input terminal of the first T-type power divider is connected to the output terminal of the input coaxial structure, and the output terminal is connected to the input terminals of the second T-type power divider and the third T-type power divider, respectively. The antenna radiating structure includes a radiating dielectric layer, a short-circuit connection structure, an antenna isolation component, and four spiral structures. The radiating dielectric layer is in contact with the feed dielectric layer and is located on the side away from the input coaxial structure. The four spiral structures are arranged in the radiating dielectric layer and are evenly distributed along the center of the radiating dielectric layer. The input end of each spiral structure is connected to the output end of the second T-type power divider and the output end of the third T-type power divider, respectively. The output ends of two opposite spiral structures are connected by a short-circuit connection structure. The antenna isolation component is arranged around the four spiral structures. The input coaxial structure receives the external coaxial feed signal and transmits it to the antenna feed network structure. The antenna feed network structure divides the input signal into four circularly polarized outputs that are 90 degrees out of phase. The antenna radiation structure receives the circularly polarized outputs and generates circularly polarized radiation.

[0007] Furthermore, the outer contour of each antenna element is square, and its relationship with the period of the antenna element conforms to the following: a=P, Where P is the period of the antenna element and a is the side length of the antenna element.

[0008] Furthermore, the power supply dielectric layer includes a first metal ground layer, a first dielectric plate, a second dielectric plate, a common metal ground layer, a third dielectric plate, a fourth dielectric plate, and a second metal ground layer arranged sequentially from bottom to top and having the same shape.

[0009] Furthermore, the first T-type power divider includes a first stripline and a first stripline transmission isolation structure for improving the transmission quality of the first stripline. The first stripline is disposed between the first dielectric substrate and the second dielectric substrate. The input end of the first stripline is connected to the input coaxial structure, and the output end is connected to the input ends of the second T-type power divider and the third T-type power divider, respectively. The first stripline transmission isolation structure includes a plurality of spaced first metal cylinders. The plurality of first metal cylinders are arranged around the periphery of the first stripline. The first metal cylinders are respectively inserted through the first dielectric substrate and the second dielectric substrate, and their two ends are respectively connected to the first metal ground layer and the common metal ground layer.

[0010] Furthermore, the second T-type power divider includes a second stripline and a second stripline transmission isolation structure for improving the transmission quality of the second stripline. The second stripline is disposed between the third dielectric substrate and the fourth dielectric substrate. The input end of the second stripline is connected to the output end of the first stripline, and the output end is connected to the input end of the antenna radiation structure. The second stripline transmission isolation structure includes a plurality of spaced second metal cylinders. The plurality of second metal cylinders are arranged around the periphery of the second stripline. The second metal cylinders are respectively inserted through the third dielectric substrate and the fourth dielectric substrate, and their two ends are respectively connected to the second metal ground layer and the common metal ground layer.

[0011] Furthermore, the third T-type power divider includes a third stripline and a third stripline transmission isolation structure for improving the transmission quality of the third stripline. The third stripline is disposed between the third dielectric substrate and the fourth dielectric substrate. The input end of the third stripline is connected to the output end of the first stripline, and the output end is connected to the input end of the antenna radiation structure. The third stripline transmission isolation structure includes multiple spaced third metal cylinders. The multiple third metal cylinders are arranged around the periphery of the third stripline. The third metal cylinders are respectively inserted through the third dielectric substrate and the fourth dielectric substrate, and their two ends are respectively connected to the second metal ground layer and the common metal ground layer.

[0012] Furthermore, the second and third stripes have the same structure and are symmetrical about the center of the common metallic strata.

[0013] Furthermore, the dielectric layer of the antenna radiation structure includes multiple fifth dielectric plates arranged sequentially from bottom to top with the same shape. The spiral structure includes multiple arc-shaped transition units and a cylinder disposed between two adjacent arc-shaped transition units. The multiple arc-shaped transition units are respectively disposed on the surface of the fifth dielectric plate away from the second metal ground layer. The cylinder passes through the fifth dielectric plate between two arc-shaped transition units. The arc-shaped transition unit includes a connecting structure and two metal patches disposed at both ends of the connecting structure. The two ends of the cylinder are fixedly connected to the metal patches respectively. The metal patches are circular with the center of the second metal ground layer as the center. There is a preset fixed rotation angle between the multiple arc-shaped transition units and between the multiple cylinders.

[0014] Furthermore, the link structure is a metal fan ring.

[0015] Furthermore, the antenna isolation assembly includes a plurality of third metal isolation pillars evenly spaced around the edge of the second metal ground layer, the third metal isolation pillars passing through a plurality of fifth dielectric plates and having their ends connected to the second metal ground layer.

[0016] Compared with existing technologies, the four-arm helical antenna phased array provided by this invention utilizes a low-temperature co-fired ceramic process combined with innovative designs such as a chain structure, sequential rotating feed, short-circuit termination optimization, and isolated component structure. While meeting the requirements of miniaturization and high integration, it effectively improves circular polarization characteristics and array scalability, making it suitable for scenarios such as Ka-band communication where high polarization purity and directional controllability are required. It has the following significant advantages: (1) Superior circular polarization performance: Chen Yuan adopted a four-feed point feeding method with a four-arm spiral antenna to achieve a feeding method with equal amplitude and 90° phase difference in a low-temperature co-fired ceramic multilayer structure. The array layout adopts a sequential rotating feeding method to output a right-hand circularly polarized beam, which can effectively reduce the axial ratio during array scanning.

[0017] (2) Compact structure and easy integration: The antenna body, feed network and isolation structure are integrated by using low temperature co-fired ceramic process, which reduces the welding and joint errors of the spiral arm in traditional spiral antennas and improves the consistency and reliability of processing.

[0018] (3) Low coupling and strong array scalability: By isolating the component structure, the mutual coupling effect is reduced while maintaining the isolation between units, which is conducive to the efficient construction and performance balance of large-scale arrays.

[0019] (4) Stable and well-matched power supply network: The multi-level stripline power supply structure combined with the coaxial transmission path reduces insertion loss and achieves precise phase control, ensuring the transmission consistency of the power supply network in the high-frequency band.

[0020] (5) Applicable to high-frequency, large-angle scanning array applications: The combination of short-circuit terminal and rotating feed improves polarization purity, and can still maintain a low axial ratio when scanning at large angles such as θ=60°, which meets the requirements of satellite communication and other systems. It is highly practical and worth promoting. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0022] Figure 2 This is a top view of the antenna array element 1 of the present invention.

[0023] Figure 3 This is a side view of the antenna array element 1 of the present invention.

[0024] Figure 4 This is a schematic diagram of the spiral structure of the antenna array element 1 of the present invention after the dielectric layer plate of the antenna radiation structure and the surrounding isolation components are hidden.

[0025] Figure 5 This is a schematic diagram of the radiation structure of the antenna array element 1 of the present invention after the dielectric layer plate that hides the antenna radiation structure.

[0026] Figure 6 This is a schematic diagram of the lower-layer feed network structure of antenna element 1 of the present invention.

[0027] Figure 7 This is a schematic diagram of the upper-layer feed network structure of antenna element 1 of the present invention.

[0028] Figure 8 This is a top view of the 2*2 four-arm helical antenna phased array of the present invention.

[0029] Figure 9 This is a bottom-view schematic diagram of the 2*2 four-arm spiral antenna phased array of the present invention.

[0030] Figure 10 This is a schematic diagram of the axial structure of the antenna array element 1 of the present invention.

[0031] Figure 11 This is a diagram showing the S-parameters and normal axis ratio of the 2*2 quad-arm spiral antenna phased array of the present invention from 26GHz to 35GHz.

[0032] Figure 12 The image shows the axial aspect ratio of the 8*8 quad-arm helical antenna phased array of the present invention when the theta angle is scanned to 0°, 45° and 60° at phi=0° from 26GHz to 35GHz.

[0033] Figure 13 The axial aspect ratio diagrams of the 8*8 quad-arm spiral antenna phased array of the present invention at 26GHz to 35GHz with phi=90°, when the theta angle is scanned to 0°, 45° and 60° respectively.

[0034] Figure 14 The radiation patterns of the 8*8 quad-arm helical antenna phased array of the present invention are scanned to 0°, 45° and 60° respectively when phi=0° at 26GHz to 35GHz.

[0035] Figure 15 The radiation patterns of the 8*8 quad-arm spiral antenna phased array of the present invention are scanned to 0°, 45° and 60° at phi=90° from 26GHz to 35GHz. Detailed Implementation

[0036] This invention provides a four-arm helical antenna phased array to solve the above-mentioned problems. In order to enable those skilled in the art to better understand the technical solution of this invention and to implement it, the technical solution of this invention will be clearly and thoroughly described below with reference to the accompanying drawings.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] Furthermore, it should be further explained that in the description of the embodiments of the present invention, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present invention, "multiple" means two or more.

[0039] The terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first," "second," "third," or "fourth" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0042] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this invention are for illustrative purposes only and do not represent the only possible implementation.

[0043] Example 1 like Figure 1 As shown, a four-arm spiral antenna phased array, realized using a low-temperature co-fired ceramic process, includes multiple antenna array elements 1 arranged in a rectangular array with adjacent antenna array elements 1 in side contact. The outer contour of each antenna array element 1 is square, and its relationship with the period of the antenna array element 1 conforms to the following: a=P, Where P is the period of antenna element 1, and a is the side length of antenna element 1.

[0044] Specifically, such as Figures 2 to 7 As shown, the structure of each antenna element 1 includes an input coaxial structure 1015, an antenna feed network structure 1014, and an antenna radiation structure. The input coaxial structure 1015 is connected to the input end of the antenna feed network structure 1014, and the output end of the antenna feed network structure 1014 is connected to the input end of the antenna radiation structure. The input coaxial structure 1015 is used to connect to the signal input end, receive the external coaxial feed signal, and transmit the external coaxial feed signal to the antenna feed network structure 1014, ensuring good impedance matching and structural stability. The antenna feed network structure 1014 is used to divide the input signal into four circularly polarized outputs with a 90-degree phase difference. The antenna radiation structure is used to generate circularly polarized radiation.

[0045] Specifically, such as Figure 3 and Figure 6 As shown, the antenna feed network structure 1014 includes a two-stage T-type power divider assembly, which is used to distribute the input signal into four output signals with equal amplitude and phases differing by ninety degrees, thereby achieving the right-hand circular polarization feed requirement.

[0046] Specifically, the antenna feed network structure 1014 includes a feed dielectric layer and a first-stage power divider and a second-stage power divider disposed in the feed dielectric layer and connected in sequence.

[0047] like Figure 6The diagram shown is a schematic of the first-stage power divider. For ease of observation, only the bottom metal ground layer is shown. The feed dielectric layer includes, from bottom to top, a first metal ground layer, a first dielectric plate, a second dielectric plate, a common metal ground layer, a third dielectric plate, a fourth dielectric plate, and a second metal ground layer, all with the same shape.

[0048] The first-stage power divider includes a first T-type power divider, used to split the input signal into two output signals 180 degrees out of phase. The first T-type power divider includes a first stripline and a first stripline transmission isolation structure 1019 for improving the transmission quality of the first stripline. The first stripline is disposed between a first dielectric substrate and a second dielectric substrate. The input end of the first stripline is connected to an input coaxial structure 1015, and its output end is connected to the input ends of the second T-type power divider and the third T-type power divider, respectively. The first stripline transmission isolation structure 1016 includes multiple spaced-apart first metal cylinders arranged around the periphery of the first stripline. The first metal cylinders pass through the first dielectric substrate and the second dielectric substrate, with their ends connected to a first metal ground layer and a common metal ground layer, respectively. By setting the first stripline transmission isolation structure 1016, the transmission quality of the first stripline can be improved, and transmission loss and crosstalk can be reduced.

[0049] Specifically, the first stripline includes a first connecting segment, a second connecting segment, and a third connecting segment. The second connecting segment and the third connecting segment are on the same straight line and intersect the first connecting segment perpendicularly. The first connecting segment is located on one side of the second connecting segment and the third connecting segment, and the second connecting segment and the third connecting segment have different lengths. One end of the first connecting segment is connected to the input coaxial structure 1015, and the second connecting segment and the third connecting segment are respectively connected to the input end of the second-stage power divider.

[0050] In addition, it should be noted that the distance between the first metal cylinder and the first strip line is appropriate, and the spacing between the first metal cylinders is also appropriate; the first metal cylinders can be appropriately spaced. Figure 6 The distance between the first metal cylinder and the first strip line shown is 0.3 mm, and the distance between the first metal cylinders is 0.25 mm.

[0051] Specifically, such as Figure 3As shown, the input coaxial structure 1015 can be a 50Ω coaxial line. The center of the coaxial line is 0.93mm horizontally and 1.25mm vertically from the horizontal center of the layer. It is connected to the first stripline through a coaxial-like structure, which corresponds to an impedance of 50Ω. The first metal cylinder surrounding the coaxial line serves the same function as the metal shell of the coaxial line. The distance between the center of the coaxial line and the center of the first metal cylinder is the outer radius of the coaxial line when the medium inside the 50Ω coaxial line is the stripline medium, which is 0.9mm. The line width of the first connection segment at the input end of the first stripline is 0.11mm and the line length is 0.39mm. The line width of the first connection segment corresponds to the 50Ω impedance of the stripline. The impedance matching line width is 0.37mm and the line length is 0.79mm. The line width corresponds to the 30Ω impedance of the stripline, and the length corresponds to the optimized one-quarter equivalent wavelength length. This ensures that the output impedance of the first-stage power divider is kept at a reasonable impedance, and the line width can also be manufactured.

[0052] The output line width of the second connection section is 0.16mm, the line length is 0.95mm, and the line width corresponds to a 45Ω impedance of the stripline.

[0053] The output line width of the third connector is the same as that of the second connector, but the line length is increased by 1.86mm, which makes the output phase of the third connector 180° different from that of the second connector.

[0054] The two outputs of the first T-type power divider are input to the second-stage power divider via a coaxial-like structure with an outer radius of 0.3 mm. The inputs of the second-stage power divider are two equal-amplitude ports 180° apart, and the port positions are symmetrical about the center of the common metallic ground layer. For transmission characteristics, the edge of the first stripline is chamfered. The size of the chamfer is not significant, as long as it is appropriate and preferably does not exceed half the linewidth at its location.

[0055] Figure 7 The schematic diagram of the second-stage power divider shown in the image has some parts of the structure hidden for easier observation.

[0056] Specifically, the second T-type power divider includes a second stripline and a second stripline transmission isolation structure for improving the transmission quality of the second stripline. The second stripline is disposed between the third and fourth dielectric substrates. The input end of the second stripline is connected to the output end of the first stripline, and the output end is connected to the input end of the antenna radiation structure. The second stripline transmission isolation structure includes multiple spaced second metal cylinders. The multiple second metal cylinders are arranged around the periphery of the second stripline. The second metal cylinders pass through the third and fourth dielectric substrates respectively, and their two ends are connected to the second metal ground layer and the common metal ground layer respectively.

[0057] Specifically, the third T-type power divider includes a third stripline and a third stripline transmission isolation structure for improving the transmission quality of the third stripline. The third stripline is disposed between the third dielectric substrate and the fourth dielectric substrate. The second and third striplines have the same structure and are symmetrical about the center of the common metal ground layer. The input end of the third stripline is connected to the output end of the first stripline, and the output ends are respectively connected to the input ends of the antenna radiation structure. The third stripline transmission isolation structure includes multiple spaced third metal cylinders. The multiple third metal cylinders are arranged around the periphery of the third stripline. The third metal cylinders are respectively inserted through the third dielectric substrate and the fourth dielectric substrate, and their two ends are respectively connected to the second metal ground layer and the common metal ground layer.

[0058] The second and third stripline transmission isolation structures have the same structure and are used to improve the transmission quality of the second and third striplines, respectively, and reduce transmission loss and crosstalk.

[0059] It should be noted that the first stripline transmission isolation structure 1016, the second stripline transmission isolation structure and the third stripline transmission isolation structure are also used to optimize the transmission of the feed network and improve the overall matching performance of the antenna. In the actual design, the spacing between the multiple second metal cylinders is the same as the spacing between the multiple first metal cylinders.

[0060] Specifically, the second and third striplines have the same structure, so we will take the second stripline as an example to illustrate its structure. The second stripline includes a fourth connecting segment, a fifth connecting segment, a sixth connecting segment, a seventh connecting segment, an eighth connecting segment, a ninth connecting segment, and a tenth connecting segment. The fifth, sixth, and seventh connecting segments are connected end-to-end vertically and fixedly, as are the eighth, ninth, and tenth connecting segments. The seventh and eighth connecting segments are on the same straight line, as are the fifth and tenth connecting segments. The fifth and tenth connecting segments are each connected to one end of the fourth connecting segment. The other end of the fourth connecting segment serves as an input terminal and is connected to the output terminal of the first-stage power divider through a coaxial structure. The adjacent ends of the seventh and eighth connecting segments serve as output terminals and are connected to the input terminal of the antenna radiation structure through a coaxial structure.

[0061] It should be noted that the first-stage power divider and the second-stage power divider are connected by a coaxial structure, which includes a hole drilled in a common metal stratum and a connecting metal column inserted in the hole. In this embodiment, the hole radius is 0.3 mm.

[0062] In the second-stage power divider, the second T-type power divider and the third T-type power divider are symmetrical about the center of the common metallic stratum. The input terminal of the second T-type power divider corresponds to the 180° phase port output by the first T-type power divider, and the input terminal of the third T-type power divider is the 0° phase port output by the first T-type power divider.

[0063] Taking the second T-type power divider as an example, the fourth connection segment serves as the input terminal, with a matching stripline of quarter impedance matching. The stripline length is 0.82mm, corresponding to the optimized quarter equivalent wavelength, and the width is 0.34mm, corresponding to a stripline impedance of 31Ω. The fifth, sixth, seventh, eighth, ninth, and tenth connection segments serve as impedance outputs, with a width of 0.11mm, corresponding to 50Ω. These segments are divided into the first output and the second output. The fifth, sixth, and seventh connection segments constitute the first output. The lengths of the first output stripline from the matching stripline to the output terminal are 0.98mm, 0.55mm, and 0.41mm, respectively. The second output stripline length is further extended by 0.64mm after optimization, forming a port with a 90° phase difference. In this counter-clockwise direction, the four ports have equal amplitude and a 90° phase difference between each pair. The four ports are actually distributed on a square at the center of the dielectric substrate, with each port 0.8 mm from the center. Each port is connected to the input end of the antenna radiation structure via a coaxial-like structure, causing the four helical arms to rotate 90 degrees about the antenna center, forming right-hand circular polarization. The coaxial-like structure here includes a hole drilled in the common metal ground layer and a connecting metal post inserted through the hole. In this embodiment, the radius of the hole is set to 0.4 mm.

[0064] It should be noted that the first dielectric substrate, the second dielectric substrate, the third dielectric substrate, and the fourth dielectric substrate are used to support the antenna structure. The high dielectric constant allows the antenna to be miniaturized. Its dielectric constant is 7.8, the loss tangent is 0.014, and the size is 4.7mm×4.7mm×0.276mm. The thickness of the first metal ground layer, the common metal ground layer, and the second metal ground layer is 0.01mm.

[0065] The input terminal of the antenna feed network structure 1014 is connected to the input coaxial structure 1015, and the output terminal is connected to the antenna radiating structure. The antenna feed network structure 1014 includes a first-stage power divider and a second-stage power divider connected in sequence. The first-stage power divider uses a 1-to-2T power divider to output two signals with equal amplitude and 180° phase difference to the port. The port is connected to the second-stage power divider using a coaxial-like structure. The second-stage power divider uses two more 1-to-2T power dividers to output four signals with equal amplitude and 90° phase difference to the port. The port is connected to the antenna radiating structure using a coaxial-like structure, realizing right-hand circular polarization feeding of four signals with equal amplitude and clockwise phase difference of 90°.

[0066] Antenna radiating structure such as Figure 5 As shown, for ease of demonstration, the dielectric layer of the antenna radiating structure is hidden. The antenna radiating structure is a four-armed spiral radiating structure, including a radiating dielectric layer and four spiral structures disposed within the radiating dielectric layer. The radiating dielectric layer is in contact with the feed dielectric layer and is located on the side away from the input coaxial structure 1015. The four spiral structures are identical in structure and are evenly distributed along the center of the radiating dielectric layer. The input end of each spiral structure is connected to the output end of the second T-type power divider and the output end of the third T-type power divider, respectively. The output ends of two oppositely positioned spiral structures are connected by a short-circuit connection structure 1012. Antenna isolation components 1011 are disposed around the four spiral structures to prevent signal interference.

[0067] Specifically, the dielectric layer of the antenna radiation structure includes five fifth dielectric plates arranged sequentially from bottom to top with the same shape. The fifth dielectric plate has the same shape as the first, second, third and fourth dielectric plates. The dielectric constant of the fifth dielectric plate is 7.8, the loss tangent is 0.014, and the size of each plate is 4.7mm×4.7mm×0.184mm.

[0068] Specifically, the antenna isolation assembly 1011 includes multiple third metal isolation pillars evenly spaced around the edge of the second metal ground layer. These third metal isolation pillars pass through five fifth dielectric substrates and are connected at their ends to the second metal ground layer. They are spaced a predetermined distance from the four helical structures, thus isolating the array elements. This facilitates axial ratio optimization for large-scale array scanning and reduces the sidelobe level of the array antenna, improving array efficiency and axial ratio. Furthermore, the presence of the antenna isolation assembly 1011 effectively reduces the coupling effect between antenna elements 1 when forming an array. This allows for the optimization and determination of the large-scale array effect by observing the radiation effect of the small array when forming a larger phased array. The radius of the third metal isolation pillar is 0.1 mm, the height is 0.97 mm, and the spacing between adjacent third metal isolation pillars is 0.45 mm.

[0069] Specifically, Figure 4 A spiral structure is shown. For ease of demonstration, the dielectric layer of the antenna radiation structure and the surrounding antenna isolation components 1011 are hidden. Each spiral structure includes five arc-shaped transition units and a cylinder disposed between two adjacent arc-shaped transition units. Specifically, the five arc-shaped transition units are respectively disposed on the surface of the fifth dielectric plate away from the second metal ground layer. The cylinder passes through the fifth dielectric plate between two arc-shaped transition units. The arc-shaped transition unit includes a connecting structure 1013 and two metal patches disposed at both ends of the connecting structure 1013. The two ends of the cylinder are fixedly connected to the metal patches respectively.

[0070] Specifically, the link structure 1013 can be a metal fan ring.

[0071] Specifically, the metal patch is circular, with the center of the second metal layer as the center, and there are preset fixed rotation angles between the five arc plate transition units and between the four cylinders.

[0072] Specifically, five arc-shaped transition units and four cylinders form a spiral structure. This spiral structure is a spiral-shaped ascending structure that rotates around the center of the second metal ground layer. This structure is used to realize the radiation structure of the spiral antenna. The rotation angle and connection dimensions of each layer control the antenna's operating frequency and circular polarization performance. The final dimensions of the spiral structure are: the radius of the metal patch is 0.21 mm, the preset fixed rotation angle is 25.5°, the linewidth of the fan ring is 0.32 mm, the radius of the cylinder is 0.11 mm, and the height is 0.184 mm. The radius of the cylinder and the fixed rotation angle can be adjusted to adjust the axial ratio and matching parameters of the antenna array elements.

[0073] Specifically, such as Figure 2 As shown, the short-circuit connection structure 1012 can be a rectangular metal patch connected to the output ends of two opposing spiral structures. The opposing spiral structures are connected by the rectangular patch to form a vertical cross shape. Compared with the open-circuit model of a four-walled spiral antenna, this effectively reduces the number of layers. Furthermore, the axial ratio can be adjusted by controlling the width of the rectangular patch, allowing for adjustment of the axial ratio during large-angle scanning in phased arrays. In this embodiment, the rectangular patch has dimensions of 1.6mm × 0.31mm × 0.01mm. Both ends of the rectangular patch are connected to the centers of the metal patches of the two spiral structures, forming a vertical cross structure.

[0074] Specifically, the rectangular and metal patches are made of copper, which is easily conductive.

[0075] For antenna element 1, it is fed through input coaxial structure 1015, receiving signals in a quasi-coaxial manner. After passing through the first-stage power divider, it outputs two signals with equal amplitude and a 180° phase difference, which then pass through the quasi-coaxial structure to the second-stage power divider. The second-stage power divider, through the second T-type power divider and the third T-type power divider, finally outputs four signals with equal amplitude and a 90° phase difference, thus forming a right-hand circularly polarized feeding configuration. This can greatly reduce the axial ratio of the antenna and improve performance. The output terminals of the second T-type power divider and the third T-type power divider are connected to the input terminals of the antenna radiating structure. Isolation structures, such as the first stripline transmission isolation structure 1016, the second stripline transmission isolation structure, and the third stripline transmission isolation structure, are set around the antenna feeding network structure 1014 to optimize the overall effect of the antenna feeding network structure 1014.

[0076] When antenna array elements 1 are used to form an array, the antenna array elements 1 are arranged in a sequential rotational feeding manner to form a 2*2 minimum sequential rotation unit, such as... Figure 8 As shown, a 2*2 quad-arm spiral antenna phased array is displayed. This is the smallest sequentially rotating quad-arm spiral antenna phased array. By rotating one element antenna by 90°, 180°, and 270° and then arranging it in a clockwise order, the feed phase in the normal direction is also 90° apart in a clockwise direction, forming a right-hand circularly polarized array. When scanning angle, phase superposition is used. The element spacing is the same as the size of the dielectric substrate of antenna element 1, which is 4.7mm. Sequential rotation feeding can significantly optimize the axial ratio. Figure 9 The diagram shows a bottom-view layout of a 2x2 quad-arm spiral antenna phased array. Specifically, in the bottom view, you can see that a fixed element is rotated 90°, 180°, and 270° counterclockwise, and then translated clockwise. Figure 10 A schematic diagram of the axial structure of one of the antenna array elements 1 is shown. Figure 11 The diagram shows the S-parameters and normal axis ratio of the 2*2 quad-arm helical antenna phased array of the present invention from 26GHz to 35GHz. The S-parameters of the four ports are all less than -10dB from 26GHz to 34GHz, indicating good matching, and the normal axis ratio is less than 1.5dB.

[0077] In an 8*8 phased array, the 2*2 minimum sequential rotating units are horizontally and vertically translated, that is, four 2*2 minimum sequential rotating units form an 8*8 sequential rotating power supply array. Figure 1 The image shows the overall structure of a four-arm spiral antenna phased array, which adopts a clockwise rotating element arrangement. Figure 12 The image shows the axial aspect ratio of the 8*8 quad-arm helical antenna phased array of the present invention at 26GHz to 35GHz, with phi=0° and theta angles scanned to 0°, 45°, and 60° respectively. Figure 13 The axial ratio diagrams of the 8*8 quad-arm helical antenna phased array of the present invention are shown when scanning angles of 0°, 45° and 60° at 26GHz to 35GHz, with phi=90°. In the frequency band of 26GHz to 34GHz, whether in the xoz plane or the yoz plane, the array axial ratio is basically less than 3dB and the normal axial ratio is basically less than 1.5dB when performing large-angle scanning, thus realizing the good scanning characteristics of the phased array. Figure 14 The radiation patterns of the 8*8 quad-arm helical antenna phased array of the present invention are shown when scanning to 0°, 45° and 60° at phi=0° and theta angles, respectively, in the range of 26GHz to 35GHz. Figure 15 The radiation patterns of the 8*8 quad-arm spiral antenna phased array of the present invention are scanned to 0°, 45° and 60° at phi=90° from 26GHz to 35GHz. At this time, the normal gain is about 21dBi, and the gain changes slowly when scanning at large angles.

[0078] To verify the effectiveness, the performance of the four-arm helical antenna phased array was compared with that of other circularly polarized millimeter-wave phased arrays. The comparison results are shown in the table below. Table 1. Performance Comparison of Quad-Arm Spiral Antenna Phased Array with Other Circularly Polarized Millimeter-Wave Phased Arrays The planar microstrip antennas used for comparison in Table 1 employ a multi-layer structure using a low-temperature co-fired ceramic process. The radiating element is a traditional planar patch, typically excited by microstrip line feeding. Due to the structural characteristics of patch antennas, their bandwidth and polarization purity are limited. At a relatively large scan angle of approximately ±45°, the sidelobe level is approximately −10dB, which is high and difficult to meet the high-performance requirements of wide bandwidth and large scan angle.

[0079] The magnetoelectric dipole antenna used in Table 1 combines a magnetic dipole and an electric dipole radiation structure. It achieves broadband dual polarization through a slot-coupled feeding method. Within a wide coverage frequency range of 22.5 GHz–32.5 GHz, the maximum scanning angle is about ±56°, but the sidelobe level is about −8.5 dB. Its sidelobe suppression capability is limited, and the polarization stability decreases significantly at large scanning angles.

[0080] The stacked microstrip antennas used for comparison in Table 1 employ a multi-layer dielectric stacked structure and are equipped with dual-fed excitation. The frequency range is 22.55GHz-27.5GHz, and the bandwidth and matching performance are improved compared to single-layer patches. However, the frequency range is relatively narrow, the scanning angle is about ±51°, and the sidelobe level is about −12.9dB, which makes it difficult to meet the requirements of higher frequency bands and larger scanning angles.

[0081] This invention provides a four-arm helical phased array antenna. Utilizing the multi-layer integration capabilities of low-temperature co-fired ceramic technology, combined with innovative designs such as a chain structure, sequential rotating feed, short-circuit termination optimization, and isolation components, it effectively improves circular polarization characteristics and array scalability while meeting miniaturization and high integration requirements. It is suitable for scenarios with high requirements for polarization purity and directional controllability, such as Ka-band communication. It achieves wideband coverage of 26GHz-34GHz and maintains a low sidelobe level of −13.9dB at a large scan angle of ±60°, significantly improving beam quality and anti-interference capabilities. Furthermore, the invention features a compact design and high feed network integration, facilitating seamless expansion of large-scale arrays. It effectively reduces inter-unit coupling and array complexity, ensuring stable performance and manufacturing consistency of large arrays under wideband and high scan angle conditions. With strong practicality, it is worthy of widespread adoption.

[0082] The above-disclosed embodiments are merely preferred embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A four-arm helical antenna phased array, characterized in that, The process utilizes a low-temperature co-fired ceramic process and includes multiple antenna array elements (1). The multiple antenna array elements (1) are arranged in a rectangular array and adjacent antenna array elements (1) are in contact. Each antenna array element (1) includes: Input coaxial structure (1015); The antenna feed network structure (1014) includes a feed dielectric layer and a first T-type power divider, a second T-type power divider and a third T-type power divider disposed in the feed dielectric layer. The input end of the first T-type power divider is connected to the output end of the input coaxial structure (1015), and the output ends are respectively connected to the input ends of the second T-type power divider and the third T-type power divider. The antenna radiating structure includes a radiating dielectric layer, a short-circuit connection structure (1012), an antenna isolation component (1011), and four spiral structures. The radiating dielectric layer is in contact with the feed dielectric layer and is located on the side away from the input coaxial structure (1015). The four spiral structures are disposed in the radiating dielectric layer and are evenly distributed along the center of the radiating dielectric layer. The input end of each spiral structure is connected to the output end of the second T-type power divider and the output end of the third T-type power divider, respectively. The output ends of two opposite spiral structures are connected through the short-circuit connection structure (1012). The antenna isolation component (1011) is disposed around the four spiral structures. The input coaxial structure (1015) receives the external coaxial feed signal and transmits the external coaxial feed signal to the antenna feed network structure (1014). The antenna feed network structure (1014) divides the input signal into four circularly polarized outputs with a phase difference of 90 degrees. The antenna radiation structure receives the circularly polarized output and generates circularly polarized radiation.

2. The four-arm spiral antenna phased array according to claim 1, characterized in that, The outer contour of each antenna element (1) is square, and its relationship with the period of the antenna element (1) is as follows: a=P, Where P is the period of antenna element (1) and a is the side length of antenna element (1).

3. The four-arm spiral antenna phased array according to claim 1, characterized in that, The power supply dielectric layer includes a first metal ground layer, a first dielectric plate, a second dielectric plate, a common metal ground layer, a third dielectric plate, a fourth dielectric plate, and a second metal ground layer arranged sequentially from bottom to top and having the same shape.

4. The four-arm spiral antenna phased array according to claim 3, characterized in that, The first T-type power divider includes a first stripline and a first stripline transmission isolation structure (1016) for improving the transmission quality of the first stripline. The first stripline is disposed between the first dielectric substrate and the second dielectric substrate. The input end of the first stripline is connected to the input coaxial structure (1015), and the output end is connected to the input ends of the second T-type power divider and the third T-type power divider, respectively. The first stripline transmission isolation structure (1016) includes a plurality of spaced first metal cylinders. The plurality of first metal cylinders are arranged around the periphery of the first stripline. The first metal cylinders are respectively inserted through the first dielectric substrate and the second dielectric substrate, and their two ends are respectively connected to the first metal ground layer and the common metal ground layer.

5. The four-arm spiral antenna phased array according to claim 3, characterized in that, The second T-type power divider includes a second stripline and a second stripline transmission isolation structure for improving the transmission quality of the second stripline. The second stripline is disposed between the third dielectric substrate and the fourth dielectric substrate. The input end of the second stripline is connected to the output end of the first stripline, and the output end is connected to the input end of the antenna radiation structure. The second stripline transmission isolation structure includes a plurality of spaced second metal cylinders arranged around the periphery of the second stripline. The second metal cylinders pass through the third dielectric substrate and the fourth dielectric substrate, and their two ends are respectively connected to the second metal ground layer and the common metal ground layer.

6. The four-arm spiral antenna phased array according to claim 5, characterized in that, The third T-type power divider includes a third stripline and a third stripline transmission isolation structure for improving the transmission quality of the third stripline. The third stripline is disposed between the third dielectric substrate and the fourth dielectric substrate. The input end of the third stripline is connected to the output end of the first stripline, and the output end is connected to the input end of the antenna radiation structure. The third stripline transmission isolation structure includes multiple spaced third metal cylinders. The multiple third metal cylinders are arranged around the periphery of the third stripline. The third metal cylinders are respectively inserted through the third dielectric substrate and the fourth dielectric substrate, and their two ends are respectively connected to the second metal ground layer and the common metal ground layer.

7. The four-arm spiral antenna phased array according to claim 6, characterized in that, The second and third strips have the same structure and are symmetrical about the center of the common metallic strata.

8. The four-arm spiral antenna phased array according to claim 5, characterized in that, The dielectric layer of the antenna radiation structure includes multiple fifth dielectric plates arranged sequentially from bottom to top with the same shape. The spiral structure includes multiple arc-shaped transition units and a cylinder disposed between two adjacent arc-shaped transition units. The multiple arc-shaped transition units are respectively disposed on the surface of the fifth dielectric plate away from the second metal ground layer. The cylinder passes through the fifth dielectric plate between two arc-shaped transition units. The arc-shaped transition unit includes a connecting structure (1013) and two metal patches respectively disposed at both ends of the connecting structure (1013). The two ends of the cylinder are fixedly connected to the metal patches respectively. The metal patches are circular with the center of the second metal ground layer as the center. There is a preset fixed rotation angle between the multiple arc-shaped transition units and between the multiple cylinders.

9. The four-arm spiral antenna phased array according to claim 8, characterized in that, The link structure (1013) is a metal fan ring.

10. The four-arm spiral antenna phased array according to claim 5, characterized in that, The antenna isolation assembly (1011) includes a plurality of third metal isolation pillars evenly spaced around the edge of the second metal ground layer. The third metal isolation pillars pass through a plurality of fifth dielectric plates and are connected at their ends to the second metal ground layer.

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