A low profile ultra-wideband tightly coupled antenna array with super large frequency multiplication ratio

Abstract

The application discloses a low-profile ultra-wideband tightly coupled antenna array with a super large frequency multiplication ratio, which comprises an array unit, the array unit comprises a first dielectric substrate, a second dielectric substrate, a wide-angle matching layer metal sheet, a dipole radiation unit, a capacitive coupling metal sheet, an intermediate dielectric substrate, a gable gap resistance sheet, a metal floor and a three-layer tapered balun; the wide-angle matching layer metal sheet is printed on the top intermediate layer of the first dielectric substrate and the second dielectric substrate; the dipole radiation unit is printed directly below the wide-angle matching layer metal sheet; the capacitive coupling metal sheet is printed on the front and back sides of the dipole radiation unit and the outer sides of the first dielectric substrate and the second dielectric substrate; the intermediate dielectric substrate is printed on the middle of the outer side of the first dielectric substrate; the gable gap resistance sheet is printed on the outer surface of the dielectric substrate; the metal floor is located at the bottom of the antenna unit; and the three-layer tapered balun is arranged between the metal floor and the dipole antenna radiation unit. The application has the advantages of super wide bandwidth, low profile and simple structure and is beneficial to processing and production.

Description

Technical Field

[0001] This invention belongs to the field of ultra-wideband antenna technology, specifically relating to a low-profile ultra-wideband tightly coupled antenna array with an ultra-high octave ratio. Background Technology

[0002] In recent years, with the continuous development of wireless communication technology, the application scenarios of wireless communication systems have become increasingly diverse. As part of the wireless communication system, the antenna, as a terminal component for both transmission and reception, affects the performance of the entire wireless communication system.

[0003] Low-profile ultra-wideband antennas and arrays are key components of many advanced communications and electronic warfare systems. For these systems, ultra-wideband antenna arrays replace systems composed of several narrowband antennas, resulting in significant savings in power, cost, and space. They also enable higher data rates and more secure spread spectrum communications. In addition to wide bandwidth, these arrays must also possess low profile characteristics and be able to operate over a wide scan range to achieve comprehensive spatial coverage from their designated platform.

[0004] Tightly coupled antennas are a type of ultra-wideband antenna, characterized by high transmission rates, ultra-wideband coverage, strong anti-interference capabilities, low profile, miniaturization for easy integration, and low cost. Originating from Professor Wheeler's Huygens continuous current sheet array theory, tight-coupled antennas differ from traditional microstrip patch antennas where the broadband array elements are spaced relatively far apart. Tightly coupled arrays are densely packed, allowing a continuous current to form on the array surface. Ultra-wideband matching is achieved through the dynamic balance between the coupling capacitance between dipoles and the inductance between the dipole and the reflector throughout the entire frequency band, resulting in a significantly smaller size compared to traditional antenna arrays. Furthermore, tightly coupled antennas are phased array antennas; by introducing a phase difference between their ports, the antenna can radiate in different directions. Therefore, applying tight coupling technology to wireless communication systems has significant practical engineering implications.

[0005] Patent CN 114006165 A discloses an ultra-wideband tightly coupled antenna array using resistive elements to extend bandwidth. However, it only covers the 9th harmonic and cannot cover the UHF band. The resistive elements are difficult to fabricate and require additional support structures for fixation. The conventional Marchand balun used cannot achieve a wider bandwidth. Patent CN115966890A discloses an ultra-wideband tightly coupled array covering the X-Ku band, but it does not use a lossy resistive layer, resulting in a narrow bandwidth of only 2.5 harmonics. Furthermore, it uses coaxial feeding, requiring the entire substrate to be drilled for feeding, making fabrication difficult. Patent CN115911837A discloses an ultra-wideband tightly coupled array using a metal shielding layer, but its bandwidth is 10:1 and its structure is particularly complex. The invention patent with publication number CN112701455B proposes a phased array antenna with a large octave band and ultra-wide scanning angle. However, it is limited by the traditional Vivaldi antenna, which does not incorporate capacitive tight coupling, resulting in a bandwidth of only 9:1. Its structural size is that of a traditional half-wavelength array, which is relatively large and cannot achieve a low profile and small cross-sectional area. The invention with publication number CN208782029U designs an extremely wideband printed monopole antenna that can achieve a bandwidth exceeding 40:1. However, it uses a switch to control the filtering circuit. The two different operating modes require manual control of the switch to switch between different operating frequency bands to achieve ultra-wideband performance. Furthermore, the monopole antenna has a large cross-section, with a length approaching 500mm, making miniaturization impossible.

[0006] In summary, although some ultra-wideband antenna arrays designed using tight coupling techniques have emerged, these antennas cannot simultaneously achieve both high bandwidth and low profile / small size, nor can they achieve ultra-high octave ratios. Furthermore, the increased bandwidth leads to more complex structures and more difficult fabrication. Therefore, designing an ultra-wideband antenna with ultra-high bandwidth and coverage of multiple frequency bands has become an urgent problem to be solved. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a low-profile ultrawideband tightly coupled antenna array with an ultra-high octave ratio. This low-profile ultrawideband tightly coupled antenna array covers the UHF to C bands and has the advantages of ultra-wideband, low profile, simple structure, and is easy to manufacture.

[0008] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0009] A low-profile ultrawideband tightly coupled antenna array with an ultra-high frequency doubling ratio includes nine array elements arranged periodically in a row.

[0010] A single array unit includes a first dielectric substrate, a second dielectric substrate, a wide-angle matching layer metal sheet, a dipole radiating unit, a capacitively coupled metal sheet, an intermediate dielectric substrate, a mountain-shaped slot resistor sheet, a metal ground plane, and a three-layer conical balun.

[0011] The first dielectric substrate and the second dielectric substrate are the same size;

[0012] A wide-angle matching layer metal sheet is printed in the top intermediate layer of the first dielectric substrate and the second dielectric substrate;

[0013] The dipole radiating unit is printed between the first dielectric substrate and the second dielectric substrate, directly below the wide-angle matching layer metal sheet.

[0014] Capacitively coupled metal sheets are printed on the front and rear sides of the dipole radiating unit, and on the outer sides of the first and second dielectric substrates.

[0015] The intermediate dielectric substrate is printed on the outer middle part of the first dielectric substrate;

[0016] A mountain-shaped gap resistor is printed on the outer surface of the dielectric substrate.

[0017] The metal ground plane is located at the bottom of the antenna unit;

[0018] A three-layer conical balun is placed between the metal floor and the dipole antenna radiating element to feed the dipole.

[0019] To optimize the above technical solution, the specific measures also include:

[0020] The first and second dielectric substrates mentioned above are rectangular structures, all made of Rogers RO3003 material with a dielectric constant of 3, a thickness of 0.25 mm, a width of 16.1 mm, and an overall height of 240 mm.

[0021] The aforementioned intermediate dielectric substrate has a rectangular structure, is made of FR-4 material, has a dielectric constant of 4.4, a thickness of 0.4 mm, a length of 26.5 mm, a width of 16.1 mm, and a height of 192 mm from the metal ground.

[0022] The aforementioned wide-angle matching layer metal sheet consists of four identical metal sheets: a first metal sheet, a second metal sheet, a third metal sheet, and a fourth metal sheet. Each metal sheet is 5 mm long and 3.8 mm wide, with a spacing of 0.3 mm between adjacent metal sheets.

[0023] The aforementioned capacitively coupled metal sheets are closely attached to the outer surfaces of both sides of the first and second dielectric substrates, and are positioned at the same height as the dipole antenna radiating element. They are divided into four metal sheets, one on the left and one on the right, and one in the front and one in the back. The four metal sheets are the same size, with each sheet having a height of 10 mm and a width of 7.55 mm.

[0024] The aforementioned conical balun includes an intermediate layer power supply section and a grounding section, with a total height of 216.4 mm;

[0025] The width of the intermediate layer feed portion is 0.15 mm, and it is located between the first dielectric substrate and the second dielectric substrate;

[0026] The grounding section is divided into a front ground connection and a rear ground connection;

[0027] The rear side that touches the ground includes the short side, the long side, and the lower half.

[0028] The width of the short side is 0.15mm, and the width of the long side is 2.5mm;

[0029] The lower half has the same structural dimensions as the front ground plane. The lower half is connected to the front ground plane by two rows of metal through holes passing through the first dielectric substrate and the second dielectric substrate.

[0030] The two rows of metal through holes 88 have a through hole radius of 0.15mm, and each row consists of twenty-two through holes;

[0031] The front side of the ground has a short side width of 2.5mm and a length of 44mm, and a long side width of 16.1mm and a length of 18mm.

[0032] The aforementioned dipole radiating unit is located at a height of 232.4 mm, and includes a left dipole, a right dipole, and a first rectangular feed line, a second rectangular feed line, and a third rectangular feed line between them;

[0033] The left dipole is the same size as the right dipole, with a height of 9 mm and a width of 4.86 mm. It is fed by a conical balun and connected to the top of the conical balun by a first rectangular feed line, a second rectangular feed line, and a third rectangular feed line. The second rectangular feed line is 0.5 mm long and 3 mm wide, and is led out from the middle of the dipole.

[0034] The first rectangular feed line is 1.64mm long and 4mm wide, connecting the second and third rectangular feed lines;

[0035] The third rectangular feed line is 13.5mm long and 0.9mm wide, connecting the first rectangular feed line and the tapered balun;

[0036] The bottom of the right dipole is connected to the conical balun by a metal cylindrical through-hole passing through the second dielectric substrate.

[0037] The aforementioned intermediate dielectric substrate is located in the upper middle part of the entire antenna array, and a mountain-shaped slot resistor is printed on the outer surface of the intermediate dielectric substrate.

[0038] The width of the mountain-shaped slot resistor is 16.1mm, the length is 26.5mm, and the height is 192mm. The width of the mountain-shaped slot on the mountain-shaped slot resistor is 1mm, the length of the long side of the mountain-shaped slot is 20mm, the length of the short side of the mountain-shaped slot is 10mm, and the length of the middle slot of the mountain-shaped slot is 7mm.

[0039] The aforementioned metal floor is made of PEC material.

[0040] The present invention has the following beneficial effects:

[0041] This invention discloses an ultra-wideband, tightly coupled antenna array with a low profile and small cross-section, covering the UHF to C-band (0.13-6.3 GHz) frequency range. Each antenna array consists of nine array elements arranged periodically in a row. The structure of a single antenna array element includes: a double-layer dielectric substrate, a wide-angle matching layer frequency selective surface, a dipole antenna element, a novel conical balun with a double-layer ground plane, a special lossy resistive layer structure with a mountain-shaped slot, and a metal ground plane. The wide-angle matching layer consists of four square metal patches, forming a frequency selective structure and improving the impedance matching performance between the antenna array and free space. The novel dipole antenna radiating element consists of three layers of rectangular metal sheets. Adjacent dipoles are capacitively coupled through metal plates placed on the front and back sides of the substrate to achieve ultra-wideband characteristics. The special lossy resistive layer with a mountain-shaped slot covers the front side of the dielectric substrate, which can suppress common-mode resonance and improve ultra-wideband impedance matching.

[0042] This invention employs a special method for placing the lossy resistive layer, resulting in better performance and easier fabrication compared to traditional lossy resistive layers. The antenna design of this invention features a three-layered feeding structure for the conical balun, with two ground planes positioned on the inner and outer sides. This allows for better ultra-wideband impedance matching and a simpler structure. The tightly coupled antenna array of this invention is fabricated on a PCB board, achieving an extremely wide bandwidth (48:1) with a simple structure. Its height is only 0.1 times the low-frequency wavelength, and its cross-sectional dimensions are only 16.1 mm, offering advantages in space and cost savings and demonstrating promising application prospects.

[0043] The antenna array of this invention is based on tight coupling technology and features a series of unique structures, including a resistive sheet with a surface-mounted groove and longitudinally placed along the z-axis, a dipole radiating element composed of three layers of metal sheets, and a novel conical balun with a double-layer ground plane. This achieves an extremely wide bandwidth covering the 48.5th harmonic of the UHF-C band, while maintaining a height of only 0.1 times the low-frequency wavelength and a cross-sectional size of only 16.1 mm, resulting in a low profile and small cross-section. By placing the resistive sheet vertically along the z-axis and creating a groove on it, this invention makes the overall antenna structure more stable and easier to manufacture, effectively suppressing common-mode resonance within the passband and achieving an extremely wide impedance bandwidth of 0.13 GHz to 6.3 GHz (VSWR < 3).

[0044] This invention features an antenna with a height of only 0.1 times the low-frequency wavelength and a length and width of only 16.1 mm, exhibiting a low profile and wide scanning angle, making the antenna array more suitable for various communication systems. This invention uses a frequency selective surface composed of four metal sheets instead of the traditional wide-angle matching layer, saving space, facilitating fabrication, and enabling better impedance matching between the antenna array and free space. This invention employs an improved novel three-layer conical balun structure, where the double-layer ground plane design allows for ultra-wideband impedance matching between the high impedance at the dipole and the port impedance. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the unit structure of an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of a radiation unit according to an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the dimensions of the three-layer conical balun according to an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the resistor dimensions according to an embodiment of the present invention;

[0049] Figure 5 This is a voltage standing wave ratio (VSWR) diagram of the antenna element of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0051] Although the steps in this invention are arranged by reference numerals, this is not intended to limit the order of the steps. Unless the order of the steps is explicitly stated or the execution of a step requires other steps as a basis, the relative order of the steps can be adjusted. It is understood that the term "and / or" as used herein refers to and covers any and all possible combinations of one or more of the associated listed items.

[0052] This invention relates to an ultra-wideband tightly coupled antenna array covering the UHF to C-band frequencies. Each antenna array consists of nine array elements arranged periodically. Each antenna array has a periodic structure, and the array elements are arranged in a one-dimensional manner. For ease of understanding, Figure 1 Only one unit is drawn in the diagram; in actual use, the unit needs to be extended to the left and right.

[0053] A single array unit includes two identical first dielectric substrates 1 and second dielectric substrates 2, a wide-angle matching layer metal sheet 3 printed on the top middle layer of the first dielectric substrates 1 and second dielectric substrates 2, a dipole radiating unit 5 printed in the middle of the first dielectric substrate (1) and second dielectric substrate (2) and directly below the wide-angle matching layer metal sheet 3, capacitive coupling metal sheets 4 printed on the front and rear sides of the dipole radiating unit 5 and on the outer sides (outer surfaces of the first dielectric substrates 1 and second dielectric substrates 2), an intermediate dielectric substrate 6 printed in the middle of the outer side of the first dielectric substrate 1, a mountain-shaped slot resistor sheet 7 printed on the outer surface of the outer side of the dielectric substrate 6, a metal ground plane 9 located at the bottom of the antenna unit, and a three-layer conical balun 8 feeding between the bottom metal ground plane 9 and the dipole antenna radiating unit 5.

[0054] The first dielectric substrate 1 and the second dielectric substrate 2 are rectangular structures, and all materials are Rogers RO3003 with a dielectric constant of 3, a thickness of 0.25 mm, a width of 16.1 mm, and an overall height of 240 mm.

[0055] In this invention, the dielectric substrate consists of two layers of the same size. The thickness of each layer is 0.25 mm, the width is 16.1 mm, and the height is 240 mm. The material used is Rogers RO3003 with a dielectric constant of 3.

[0056] The intermediate dielectric substrate 6 has a rectangular structure, is made of FR-4 material, has a dielectric constant of 4.4, a thickness of 0.4 mm, a length of 26.5 mm, a width of 16.1 mm, and a height of 192 mm from the metal ground plate 9.

[0057] like Figure 2 As shown, the wide-angle matching layer metal sheet 3 is composed of four identical first metal sheet 31, second metal sheet 32, third metal sheet 33 and fourth metal sheet 34, with a length of 5mm, a width of 3.8mm and a spacing of 0.3mm between adjacent metal sheets.

[0058] The dipole radiating unit 5 is located between the first dielectric substrate 1 and the second dielectric substrate 2, below the wide-angle matching layer metal sheet 3, at a height of 232.4 mm.

[0059] like Figure 2 As shown, the dipole radiation unit 5 includes a left dipole 51, a right dipole 52, and a first rectangular feed line 511, a second rectangular feed line 512, and a third rectangular feed line 513 between them.

[0060] The left dipole 51 and the right dipole 52 have the same dimensions, with a height of 9 mm and a width of 4.86 mm.

[0061] The dipole radiating unit 5 is fed by a conical balun 8 and is connected to the top of the conical balun 8 by a first rectangular feed line 511, a second rectangular feed line 512, and a third rectangular feed line 513. The second rectangular feed line 512 is 0.5 mm long and 3 mm wide, and is led out from the middle of the dipole.

[0062] The first rectangular feed line 511 is 1.64 mm long and 4 mm wide, connecting the second rectangular feed line 512 and the third rectangular feed line 513;

[0063] The third rectangular feed line 513 is 13.5 mm long and 0.9 mm wide, connecting the first rectangular feed line 511 and the tapered balun 8.

[0064] The bottom of the right dipole 52 is connected to the ground 85 on the rear side of the conical balun 8 by a metal cylindrical through-hole 81 passing through the second dielectric substrate 2.

[0065] The left dipole 51 is directly connected to the intermediate layer feed section 86 of the conical balun 5 via a metal strip.

[0066] The capacitive coupling metal sheet 4 is closely attached to the outer surfaces of both sides of the first dielectric substrate 1 and the second dielectric substrate 2, at the same height as the dipole antenna radiating element 5. It consists of four metal sheets, one on each side and one in front and one behind, all identical in size: 10mm high and 7.55mm wide. Capacitive coupling is achieved through a double-layer capacitive coupling sheet. This capacitive coupling can cancel out ground inductance. Compared to directly using the antenna radiating element for capacitive coupling, the double-layer capacitive coupling is more stable and easier to adjust the capacitance.

[0067] like Figure 3 As shown, the conical balun 8 has a three-layer structure, including the middle layer power supply section 86 and the grounding section;

[0068] The intermediate layer power supply portion 86 is located between the first dielectric substrate 1 and the second dielectric substrate 2, and its width is 0.15 mm;

[0069] The grounding section is divided into a front grounding point 87 and a rear grounding point 85.

[0070] The rear side ground contact 85 includes a short side 82, a long side 84, and a lower half 83;

[0071] The width of the short side 82 is 0.15mm, and the width of the long side 84 is 2.5mm;

[0072] The lower half 83 has the same structural dimensions as the front ground plane 87. The lower half 83 is connected to the front ground plane 87 by two rows of metal through holes 88 passing through the first dielectric substrate 1 and the second dielectric substrate 2.

[0073] The two rows of metal through holes 88 have a through hole radius of 0.15mm, and each row consists of twenty-two through holes;

[0074] The front side of the ground has a short side width of 2.5mm and a length of 44mm, and a long side width of 16.1mm and a length of 18mm.

[0075] The total height of the three-layer conical balun 8 is 216.4 mm.

[0076] The improved coplanar waveguide-based three-layer conical balun feed structure achieves a wider impedance bandwidth compared to the Marchand balun, thus further enhancing the antenna's bandwidth.

[0077] The intermediate dielectric substrate 6 is located in the upper middle part of the entire antenna array, and a mountain-shaped slot resistor 7 is printed on the outer surface of the intermediate dielectric substrate 6.

[0078] The width of the mountain-shaped slit resistor 7 is 16.1 mm, the length is 26.5 mm, and the height is 192 mm. The width of the mountain-shaped slit 71 on the mountain-shaped slit resistor 7 is 1 mm, the length of the long side 72 of the mountain-shaped slit is 20 mm, the length of the short side 73 of the mountain-shaped slit is 10 mm, and the length of the middle slit 74 of the mountain-shaped slit is 7 mm.

[0079] This structure absorbs radiated waves and can effectively suppress common-mode resonance within the operating frequency band. Compared with the traditional ring resistor perpendicular to the z-axis, the square resistor structure parallel to the z-axis is simpler, more stable, and easier to manufacture, and its suppression of common-mode resonance is enhanced. The mountain-shaped slots etched on the surface of the resistor are beneficial for the impedance matching of the antenna, enabling the resistor to better suppress common-mode resonance at certain frequencies.

[0080] The metal ground plane 9 is located at the bottom of the entire antenna structure and serves as the grounding part of the entire antenna. The metal ground plane 9 is made of a single piece of PEC material.

[0081] In this invention, the dipole antenna, the capacitively coupled metal sheet, the wide-angle matching metal sheet, and the conical balun metal layer are all copper layers with a thickness of 0.017 mm.

[0082] Figure 5 The voltage standing wave ratio (VSWR) of the ultra-wideband tightly coupled antenna array reflects the overall impedance matching of the antenna. Within the 0.13 GHz–6.3 GHz frequency range, the VSWR is less than 3, indicating good matching and demonstrating that the embodiment of this invention achieves ultra-wideband performance.

[0083] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0084] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A low-profile ultrawideband tightly coupled antenna array with an ultra-high frequency doubling ratio, characterized in that, It includes nine array units arranged in a periodic row; each array unit includes a first dielectric substrate (1), a second dielectric substrate (2), a wide-angle matching layer metal sheet (3), a dipole radiating unit (5), a capacitively coupled metal sheet (4), an intermediate dielectric substrate (6), a mountain-shaped gap resistor sheet (7), a metal ground plate (9), and a three-layer conical balun (8). The first dielectric substrate (1) and the second dielectric substrate (2) are the same size; the wide-angle matching layer metal sheet (3) is printed on the top middle layer of the first dielectric substrate (1) and the second dielectric substrate (2); the dipole radiating unit (5) is printed in the middle of the first dielectric substrate (1) and the second dielectric substrate (2), directly below the wide-angle matching layer metal sheet (3); the capacitive coupling metal sheet (4) is printed on the front and back sides of the dipole radiating unit (5), and on the outside of the first dielectric substrate (1) and the second dielectric substrate (2); the intermediate dielectric substrate (6) is printed in the middle of the outside of the first dielectric substrate (1); the mountain-shaped gap resistor sheet (7) is printed on the outer surface of the intermediate dielectric substrate (6). The metal floor (9) is located at the bottom of the antenna unit; the three-layer conical balun (8) is placed between the metal floor (9) and the dipole antenna radiating unit (5) to feed the dipole; The conical balun (8) includes a middle layer power supply section (86) and a grounding section, with a total height of 216.4 mm. The middle layer power supply section (86) has a width of 0.15 mm and is located between the first dielectric substrate (1) and the second dielectric substrate (2). The grounding section is divided into a front ground plane (87) and a rear ground plane (85). The rear ground plane (85) includes a short side (82), a long side (84), and a lower half (83). The short side (82) has a width of 0.15 mm, and the long side (84) has a width of 0.15 mm. The width is 2.5mm; the lower half (83) has the same structural dimensions as the front ground plane (87). The lower half (83) is connected to the front ground plane (87) by two rows of metal through holes (88) passing through the first dielectric substrate (1) and the second dielectric substrate (2); the through hole radius of the two rows of metal through holes (88) is 0.15mm, and each row consists of twenty-two through holes; the short side width of the front ground plane (87) is 2.5mm, the length is 44mm, the long side width is 16.1mm, and the length is 18mm.

2. A low-profile ultrawideband tightly coupled antenna array with an ultra-high octave ratio according to claim 1, characterized in that, The first dielectric substrate (1) and the second dielectric substrate (2) are rectangular structures, all made of Rogers RO3003, with a dielectric constant of 3, a thickness of 0.25 mm, a width of 16.1 mm, and an overall height of 240 mm.

3. The low-profile ultrawideband tightly coupled antenna array with an ultra-high octave ratio according to claim 1, characterized in that, The intermediate dielectric substrate (6) has a rectangular structure, is made of FR-4 material, has a dielectric constant of 4.4, a thickness of 0.4 mm, a length of 26.5 mm, a width of 16.1 mm, and a height of 192 mm from the metal floor (9).

4. The low-profile ultrawideband tightly coupled antenna array with an ultra-high octave ratio according to claim 1, characterized in that, The wide-angle matching layer metal sheet (3) consists of four identical first metal sheet (31), second metal sheet (32), third metal sheet (33), and fourth metal sheet (34). Each metal sheet has a length of 5 mm, a width of 3.8 mm, and a spacing of 0.3 mm between adjacent metal sheets.

5. A low-profile ultrawideband tightly coupled antenna array with an ultra-high frequency doubling ratio according to claim 1, characterized in that, The capacitively coupled metal sheet (4) is attached to the outer surfaces of the first dielectric substrate (1) and the second dielectric substrate (2) on both sides. Its height is consistent with that of the dipole antenna radiating element (5). It is divided into four metal sheets on the left and right sides and front and back. The four metal sheets are the same size. The height of each metal sheet is 10mm and the width is 7.55mm.

6. A low-profile ultrawideband tightly coupled antenna array with an ultra-high octave ratio according to claim 1, characterized in that, The dipole radiation unit (5) is located at a height of 232.4 mm and includes a left dipole (51), a right dipole (52) and a first rectangular feed line (511), a second rectangular feed line (512) and a third rectangular feed line (513) between them. The left dipole (51) and the right dipole (52) are the same size, with a height of 9 mm and a width of 4.86 mm. They are fed by a conical balun (8) and connected to the top of the conical balun (8) by a first rectangular feed line (511), a second rectangular feed line (512), and a third rectangular feed line (513). The second rectangular feed line (512) is 0.5 mm long and 3 mm wide, and is led out from the middle of the left dipole (51). The first rectangular feed line (511) is 1.64 mm long and 4 mm wide, connecting the second rectangular feed line (512) and the third rectangular feed line (513). The third rectangular feed line (513) is 13.5 mm long and 0.9 mm wide, connecting the first rectangular feed line (511) and the conical balun (8). The bottom of the right dipole (52) is connected to the conical balun (8) through a metal cylindrical through-hole (81) through the second dielectric substrate (2).

7. A low-profile ultrawideband tightly coupled antenna array with an ultra-high octave ratio according to claim 1, characterized in that, The intermediate dielectric substrate (6) is located in the upper middle part of the entire antenna array, and a mountain-shaped slot resistor sheet (7) is printed on the outer surface of the intermediate dielectric substrate (6). The width of the mountain-shaped slit resistor (7) is 16.1 mm, the length is 26.5 mm, and the height is 192 mm. The width (71) of the mountain-shaped slit on the mountain-shaped slit resistor (7) is 1 mm, the length of the long side (72) of the mountain-shaped slit is 20 mm, the length of the short side (73) of the mountain-shaped slit is 10 mm, and the length of the middle slit (74) of the mountain-shaped slit is 7 mm.

8. A low-profile ultrawideband tightly coupled antenna array with an ultra-high octave ratio according to claim 1, characterized in that, The metal floor (9) is made of PEC material.

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