Dual-polarization common-aperture tight coupling array antenna based on broadband electromagnetic transparent surface

Abstract

The invention discloses a dual-polarized common-caliber tight coupling array antenna based on a broadband electromagnetic transparent surface. The dual-polarized common-caliber tight coupling array antenna comprises a low-frequency dual-polarized antenna array surface, a low-frequency feed structure, a high-frequency dual-polarized antenna array, a metal floor and a coaxial connector. The two antenna array surfaces work in different frequency bands, and the dual-polarization broadband electromagnetic transparent design is carried out on the low-frequency antenna array surface, so that the antenna arrays of the two frequency bands can work at the same time and are not shielded. The dual-polarization common-caliber tight coupling array can achieve continuous working bandwidth exceeding 10 times of frequency, the average efficiency of the full frequency band is higher than 80%, and the dual-polarization common-caliber tight coupling array has 45-degree E-plane and H-plane scanning capacity. The antenna can be applied to the design of a dual-polarization, ultra-wideband and high-efficiency array antenna, and breaks through the performance limitation of a single-polarization common-caliber tight coupling array.

Description

Technical Field

[0001] This invention belongs to the field of antenna engineering technology and relates to a dual-polarized common-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface, which meets the technical requirements of dual-polarized high-efficiency radiation and ultra-wide operating bandwidth of antenna arrays in engineering. Background Technology

[0002] With the increasing demand for multifunctionality and high integration in communication platforms operating within confined spaces, integrating disparate frequency bands into a single antenna aperture has become a key research direction. Co-aperture phased arrays, which allow multiple arrays to operate within the same physical space, have attracted widespread attention. Currently, various co-aperture techniques have been studied, including aperture multiplexing, radiating element stacking, and staggered layouts. However, phased arrays based on traditional co-aperture architectures often struggle to achieve continuous frequency band coverage, and the bandwidth of a single radiating element is relatively narrow, thus limiting the overall capacity of the communication channel.

[0003] To achieve ultra-wideband frequency coverage, tightly coupled dipole arrays have emerged as a promising solution due to their strong capacitive coupling between elements. While conventional tightly coupled antenna arrays can achieve bandwidths exceeding 10:1, they typically rely on resistive frequency-selective surface layers to suppress ground-to-ground short-circuit effects and common-mode resonances. This resistive loading inevitably leads to a significant decrease in radiation efficiency. Therefore, developing a non-resistive, high-efficiency, and low-profile ultra-wideband array remains a pressing issue.

[0004] In recent years, researchers have explored stacked structures involving multi-layer ultra-wideband arrays. For example, the paper "An Extremely Wideband Tightly Coupled Dipole Array With Shared-Aperture Configuration" proposes stacking two tightly coupled array antennas vertically to achieve ultra-wideband frequency implementation. In these designs, the upper (low-frequency) array must be electromagnetically transparent to the lower (high-frequency) array. The core bottleneck lies in the transparency mechanism of the upper antenna elements: it needs to remain transparent over a wide high-frequency range while still radiating efficiently in the low-frequency range. Furthermore, the limitation of single polarization makes it difficult to demonstrate sufficient value in practical applications. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a dual-polarized co-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface. By designing the low-frequency antenna located on the upper layer with dual-polarization broadband electromagnetic transparency, the co-aperture tightly coupled array in both high and low frequency bands can simultaneously operate in dual polarization, thus solving the problems of relatively singular polarization and insufficient scanning bandwidth of current co-aperture tightly coupled arrays.

[0006] To achieve the above objectives, the present invention employs the following solution:

[0007] As a preferred embodiment, a dual-polarized common-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface is provided. The high-frequency antenna array is located below the low-frequency antenna array. The antenna structure, from top to bottom, includes a low-frequency dual-polarized antenna array, a low-frequency feed structure, a high-frequency dual-polarized antenna array, a metal ground plane, and a coaxial connector. The low-frequency dual-polarized antenna array is located above the high-frequency dual-polarized antenna array and is placed parallel to the metal ground plane. The high-frequency dual-polarized antenna array is placed perpendicular to the metal ground plane. The low-frequency feed structure is electrically connected to the low-frequency dual-polarized antenna array. The coaxial connector is located below the metal ground plane.

[0008] Furthermore, the low-frequency dual-polarized antenna array includes a low-frequency dielectric substrate, a dual-polarized electromagnetic transparent antenna, and a low-frequency metal coupling patch. The dual-polarized electromagnetic transparent antenna is arranged in a cross shape. The four dipole arms at the center of the cross shape form a dual-polarized coupling region, and the two adjacent dipole arms at the edge of the cross shape form a single-polarized coupling region. The antenna in each polarization direction is composed of two dipoles. Staggered long slots are etched on each dipole arm. The dual-polarized electromagnetic transparent antenna and the low-frequency metal coupling patch are printed on the front and back sides of the low-frequency dielectric substrate, respectively. The low-frequency metal coupling patch includes a circular patch and a rectangular patch. The circular patch is located below or above the dual-polarized coupling region to form a stacked structure, while the rectangular patch is located below or above the single-polarized coupling region to form a stacked structure.

[0009] Furthermore, the low-frequency power supply structure includes four low-frequency power supply baluns and two 1-to-2 Wilkinson power dividers. The low-frequency power supply baluns are perpendicular to the metal ground plane, and the 1-to-2 Wilkinson power dividers are parallel to and tightly attached to the metal ground plane, and fixed with screws. Their output ports are connected to the input ports of the low-frequency power supply baluns. The low-frequency power supply balun includes a balun dielectric substrate, an exponentially gradient metal patch, and a trapezoidal gradient metal patch. The two types of metal patches are printed on the upper and lower surfaces of the balun dielectric substrate, respectively. The exponentially gradient metal patch has a gradient groove in the middle area.

[0010] Furthermore, the Wilkinson power divider is a microstrip line structure, with the microstrip line and the power divider ground plane printed on the upper and lower surfaces of the power divider dielectric substrate.

[0011] Furthermore, the high-frequency dual-polarized antenna array includes a high-frequency dielectric substrate, an integrated dipole unit, a Marchand balun feed line, a high-frequency metal coupling patch, and a wide-angle matching layer. The high-frequency dual-polarized antenna array is printed on both sides of the high-frequency dielectric substrate. The wide-angle matching layer and the integrated dipole unit are printed on the top or bottom, and the high-frequency metal coupling patch and the Marchand balun feed line are printed on the bottom or top. The high-frequency metal coupling patch is located in front of or behind the ends of the two arms of the adjacent dipole, forming a front-to-back overlapping part. The wide-angle matching layer is located above the integrated dipole unit and the metal coupling patch.

[0012] Furthermore, the coaxial connector housing is connected to a metal ground plane, and the inner core is connected to the microstrip line or Marchand balun feeder of a 1-to-2 Wilkinson power divider.

[0013] Furthermore, the low-frequency dielectric substrate, the balun dielectric substrate, and the high-frequency dielectric substrate are made of Rogersduriod 5880 with a dielectric constant of 2.2; the power divider dielectric substrate is made of Rogersduriod 6002 with a dielectric constant of 2.94.

[0014] Furthermore, all of the dielectric substrates adopt a single-layer structure.

[0015] In summary, the present invention has the following advantages:

[0016] 1. Compared with traditional strongly coupled ultra-wideband array antennas, this invention can achieve an ultra-wide bandwidth covering 0.22-2.6 GHz for more than 10 times the frequency, further expanding the bandwidth of the array antenna.

[0017] 2. Compared with the previous common-aperture strongly coupled array antennas, the antenna polarization mode is extended to a dual-line polarization form, and it has the potential to synthesize circular polarization.

[0018] 3. The overall efficiency of the array can reach over 80%. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the unit structure of Embodiment 1 of the present invention.

[0020] Figure 2 yes Figure 1 The diagram shows the disassembly of the low-frequency dual-polarized antenna array in the antenna structure shown.

[0021] Figure 3 yes Figure 1 The diagram shows the disassembled low-frequency feed balun in the antenna structure shown.

[0022] Figure 4 yes Figure 1 Front view of the Wilkinson power divider in the antenna structure shown.

[0023] Figure 5 yes Figure 1 The front view of the high-frequency dual-polarized antenna array unit in the antenna structure shown.

[0024] Figure 6 yes Figure 5 The diagram shows the disassembly of a single-polarization antenna in the antenna structure shown.

[0025] Figure 7 yes Figure 1 The overall active VSWR of the antenna structure shown.

[0026] Figure 8 yes Figure 1 The diagram shows the overall radiation efficiency of the antenna structure.

[0027] Figure 9 yes Figure 1 Gain patterns of the antenna structure shown at 0.3 GHz, 1.36 GHz, and 2.5 GHz.

[0028] The components include: 1. Low-frequency dual-polarized antenna array; 2. Low-frequency feeding structure; 3. High-frequency dual-polarized antenna array; 4. Metal ground plane; 5. Coaxial connector. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] Example 1

[0031] like Figure 1 As shown, this invention provides a dual-polarized common-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface, comprising a low-frequency dual-polarized antenna array 1, a low-frequency feeding structure 2, a high-frequency dual-polarized antenna array 3, a metal ground plane 4, and a coaxial connector 5. The high-frequency dual-polarized antenna array is located below the low-frequency dual-polarized antenna array, with the low-frequency dual-polarized antenna array placed parallel to the metal ground plane, and the high-frequency dual-polarized antenna array perpendicular to the metal ground plane. For ease of understanding, only one periodic element of the array is shown in the figure. In actual research and fabrication, the array can be expanded along both the length and width directions as shown in the figure.

[0032] The low-frequency dual-polarized antenna array 1 uses a dual-polarized bowtie-type unit as its main structure. Each polarization direction antenna consists of two dipole units. At the central cross-shaped region, the ends of the four dipole arms are interdigitated. Below this region is a circular metal patch 1.3, and below the single-polarization coupling region is a rectangular metal patch 1.4. Alternating rectangular slots are etched on the two arms of the dipole antenna. After tuning, electromagnetic transparency within the target frequency band is achieved, without obstructing the high-frequency antenna below. The dual-polarized electromagnetically transparent antenna 1.1 and the low-frequency metal coupling patches (1.3 and 1.4) are printed on both sides of a single-layer low-frequency dielectric substrate 1.2 using PCB technology. Figure 2 As shown.

[0033] The low-frequency feed structure 2 includes four low-frequency feed baluns and two Wilkinson power dividers. The low-frequency feed baluns are composed of exponentially graded metal patches 2.1 and trapezoidal graded metal patches 2.3 printed on both sides of the balun dielectric substrate 2.2, as shown below. Figure 3 As shown; the microstrip line 2.4 and the power divider ground plane 2.5 of the 1-to-2 Wilkinson power divider are printed on the top and bottom sides of the power divider dielectric substrate 2.6. The isolation resistor 2.7 is soldered between the two output port paths of the 1-to-2 Wilkinson power divider to enhance the isolation. Figure 4 As shown.

[0034] One periodic element 6 of the high-frequency dual-polarized antenna array includes an integrated dipole element 6.1, a wide-angle matching layer 6.2, a high-frequency dielectric substrate 6.3, a Marchand balun feed line 6.4, and a high-frequency metallic coupling patch 6.5, as shown below. Figure 5 and Figure 6 As shown. The wide-angle matching layer 6.2 consists of four periodically spaced, double-layer rectangular metal patches, providing good impedance matching compensation for the antenna input impedance. The integrated dipole unit 6.1, the Marchand balun feed line 6.4, and the high-frequency metal coupling patch 6.5 are printed on both sides of the single-layer high-frequency dielectric substrate 6.3 using PCB technology.

[0035] Figure 1 In the antenna structure shown, the low-frequency dielectric substrate 1.2, the balun dielectric substrate 2.2, and the high-frequency dielectric substrate 6.3 are made of Rogers Duriod 5880 with a dielectric constant of 2.2; the power divider dielectric substrate 2.6 is made of Rogers Duriod 6002 with a dielectric constant of 2.94; all dielectric substrates adopt a single-layer structure.

[0036] Figure 7 Given Figure 1The active VSWR of the antenna structure shown in the figure is less than 3 in the range of 0.22-2.6GHz, with a bandwidth of 11.8 octaves. The VSWR remains good when the E-plane and H-plane are scanned to 45°.

[0037] Figure 8 Given Figure 1 The diagram shows the total radiation efficiency of the antenna structure. It can be seen from the diagram that the average radiation efficiency is 82.4%.

[0038] Figure 9 Given Figure 1 The gain patterns of the main polarization and cross-polarization of the antenna structure shown are from left to right: 0.3 GHz, 1.36 GHz and 2.5 GHz. It can be seen that the main polarization pattern is complete and the cross-polarization isolation is good.

[0039] The above description and embodiments are merely some preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Various modifications and variations can be made to this application by those skilled in the art, but modifications and alterations based on the inventive concept are still within the protection scope of the claims of the present invention.

Claims

1. A dual-polarized common-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface, comprising a low-frequency dual-polarized antenna array, a low-frequency feeding structure, a high-frequency dual-polarized antenna array, a metal ground plane, and a coaxial connector, characterized in that: The low-frequency dual-polarized antenna array is located above the high-frequency dual-polarized antenna array. The low-frequency dual-polarized antenna array is placed parallel to the metal ground plane, while the high-frequency dual-polarized antenna array is placed perpendicular to the metal ground plane. The low-frequency feeding structure is electrically connected to the low-frequency dual-polarized antenna array. The coaxial connector is located below the metal ground plane.

2. The dual-polarized common-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface according to claim 1, characterized in that: The low-frequency dual-polarized antenna array includes a low-frequency dielectric substrate, a dual-polarized electromagnetic transparent antenna, and a low-frequency metal coupling patch. The dual-polarized electromagnetic transparent antenna is arranged in a cross shape. The four dipole arms at the center of the cross shape form a dual-polarized coupling region, and the two adjacent dipole arms at the edge of the cross shape form a single-polarized coupling region. The antenna in each polarization direction consists of two dipoles. Staggered long slots are etched on each dipole arm. The dual-polarized electromagnetic transparent antenna and the low-frequency metal coupling patch are printed on the front and back sides of the low-frequency dielectric substrate, respectively. The low-frequency metal coupling patch includes a circular patch and a rectangular patch. The circular patch is located below or above the dual-polarized coupling region to form a stacked structure, while the rectangular patch is located below or above the single-polarized coupling region to form a stacked structure.

3. The dual-polarization common-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface according to claim 1, characterized in that: The low-frequency power supply structure includes four low-frequency power supply baluns and two 1-to-2 Wilkinson power dividers. The low-frequency power supply baluns are perpendicular to the metal ground plane, and the 1-to-2 Wilkinson power dividers are parallel to and tightly attached to the metal ground plane, fixed with screws. Their output ports are connected to the input ports of the low-frequency power supply baluns. The low-frequency power supply balun includes a balun dielectric substrate, an exponentially graded metal patch, and a trapezoidal graded metal patch. The two types of metal patches are printed on the upper and lower surfaces of the balun dielectric substrate, respectively. The exponentially graded metal patch has a graded groove in the middle area. The 1-to-2 Wilkinson power divider is a microstrip line structure, and the microstrip line and the power divider ground plane are printed on the upper and lower surfaces of the power divider dielectric substrate.

4. The dual-polarization common-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface according to claim 1, characterized in that: The high-frequency dual-polarized antenna array includes a high-frequency dielectric substrate, an integrated dipole element, a Marchand balun feed line, a high-frequency metal coupling patch, and a wide-angle matching layer. The high-frequency dual-polarized antenna array is printed on both sides of the high-frequency dielectric substrate. The wide-angle matching layer and the integrated dipole element are printed on the top or bottom, and the high-frequency metal coupling patch and the Marchand balun feed line are printed on the bottom or top. The high-frequency metal coupling patch is located in front of or behind the ends of the two arms of adjacent dipoles, forming a front-to-back overlapping part. The wide-angle matching layer is located above the integrated dipole element and the metal coupling patch.

5. A dual-polarization common-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface according to claim 1, characterized in that: The coaxial connector housing is connected to the metal ground plane, and the inner core is connected to the microstrip line or Marchand balun feeder of the 1-to-2 Wilkinson power divider.

6. A dual-polarization common-aperture tightly coupled array antenna based on a broadband electromagnetically transparent surface according to claim 1, characterized in that: The low-frequency dielectric substrate, balun dielectric substrate, and high-frequency dielectric substrate are made of Rogers duriod 5880 with a dielectric constant of 2.2; the power divider dielectric substrate is made of Rogers duriod 6002 with a dielectric constant of 2.94; all dielectric substrates adopt a single-layer structure.

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