Dual-polarized tightly coupled dipole ultrawideband antenna with resistive thin film loading

Abstract

This invention discloses a dual-polarized tightly coupled dipole ultrawideband antenna with a resistive thin film. The antenna includes a dielectric matching layer with a loaded metasurface, a dipole antenna, a coupling capacitor patch, a metal via, a curved slot, a resistive thin film, a coaxial feed, a metal ground plane, a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate. This invention enables a tightly coupled antenna with dual polarization, low profile, and wide bandwidth. The invention provides a frequency coverage of 0.8–12 GHz, with active VSWRs below 3 at both ports of the dual-polarization element and isolation less than -15 dB between the two ports. The antenna element height is 33 mm, exhibiting excellent radiation characteristics. This antenna has the advantages of wide operating bandwidth, wide beam scanning range, and low profile height. It is easy to manufacture and can be conformally mounted on curved surfaces, making it significant for practical engineering applications such as electronic reconnaissance and electronic countermeasures.

Description

Technical Field

[0001] This invention belongs to the field of ultra-wideband antenna technology, specifically relating to a dual-polarized tightly coupled dipole ultra-wideband antenna with a loaded resistive thin film. Background Technology

[0002] With the increasing information transmission speed and wider signal coverage in modern society, there is a growing demand for broadband and even multi-band broadband.

[0003] The demand for high-performance antennas is also increasing. Traditional broadband antennas are mostly limited to a single frequency band, and achieving full coverage...

[0004] Multi-band antenna arrays present significant challenges. While traditional ultra-wideband antenna arrays, such as the Vivaldi array, can achieve ultra-wide operating bandwidths, their high profile and heavy weight often hinder the integration and unified design of electronic information systems. Unlike other ultra-wideband arrays, planar ultra-wideband modular arrays (PUMA) are fabricated using planar etched circuits and metal vias, allowing for the creation of simple multi-layer microwave PCB structures without the need for external balun structures. Furthermore, PUMA arrays offer low profile characteristics and modular construction. The capacitive coupling between adjacent elements in tightly coupled arrays can cancel out the inductive coupling between the antenna and the ground plane, giving them a natural technological advantage in ultra-wideband and low-profile applications. However, many key technologies for tightly coupled phased array antennas still need to be overcome. Meanwhile, dipole antennas, with their low profile, good polarization characteristics, wide bandwidth, and ease of arraying, are often used as elements in tightly coupled antenna arrays. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-polarized tightly coupled dipole ultrawideband antenna with a loaded resistive thin film, which can be mass-produced using printed circuit technology and has the advantages of small size, stable performance and low manufacturing cost.

[0006] The technical solution to achieve the purpose of this invention is as follows: a dual-polarized tightly coupled dipole ultrawideband antenna with a resistive thin film, the antenna unit comprising a dielectric matching layer with a loaded metasurface, a dipole antenna, a coupling capacitor patch, a metal via, a curved slit, a resistive thin film, a coaxial feed, a metal ground plane, a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate; the dielectric matching layer with the loaded metasurface is placed on top of the first dielectric substrate; the dipole antenna is symmetrically orthogonally placed and printed on the front and back sides of the first dielectric substrate; the coupling capacitor patch is printed on both sides of the first dielectric substrate; the coaxial feed, as the antenna feed structure, passes through the second and third dielectric substrates with the loaded resistive thin film and is connected to the dipole antenna; the curved slit is opened at the end of the dipole antenna, and the metal via is embedded inside the first dielectric substrate; the metal ground plane is placed parallel to the antenna along with the dielectric matching layer and the resistive thin film.

[0007] Compared with the prior art, the present invention has the following significant advantages: (1) It uses dipoles to introduce new reactive components, thereby replacing dielectric loading to achieve ultra-wideband impedance matching and obtain stable gain; (2) The antenna unit is fed directly with coaxial line, which improves the feeding efficiency, reduces the complexity of model design, and avoids the loss of power divider components; (3) The loading capacitor coupling, dielectric matching layer and curved slot improve some resonant frequency points of the antenna in the entire working frequency band, thereby improving the impedance matching of the antenna at low and high frequencies; (4) A resistive thin film is added between the dipole antenna and the metal ground to absorb the reflected waves from the ground in the short-circuit resonant bandwidth of the dual-polarized antenna, thereby widening the working bandwidth of the dual-polarized antenna; (5) It is produced by printed circuit technology, with a simple structure and low profile height, which is about one-quarter of the height of the working antenna in the same frequency band. It is easy to conformally fit on curved carriers and has a wide range of applications. Attached Figure Description

[0008] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0009] Figure 1 This is a schematic diagram of the overall structure of the dual-polarized tightly coupled dipole antenna with a loaded resistive thin film according to the present invention.

[0010] Figure 2 This is a front view of the two polarization units of the dual-polarization tightly coupled dipole antenna with a loaded resistive thin film according to the present invention.

[0011] Figure 3 This is a top view of the resistive thin film of the dual-polarized tightly coupled dipole antenna with resistive thin film loaded according to the present invention.

[0012] Figure 4 It is the active standing wave ratio (VSWR) of the dual-polarized tightly coupled dipole antenna with a resistive thin film loaded in this invention.

[0013] Figure 5 This refers to the two-port isolation of the dual-polarized tightly coupled dipole antenna with a resistive thin film loaded in this invention.

[0014] Figure 6 This is a comparison diagram of the single-polarization gain and dual-polarization gain of the dual-polarization tightly coupled dipole antenna with a resistive thin film loaded according to the present invention.

[0015] Figure 7 The radiation pattern results of the dual-polarized tightly coupled dipole antenna with resistive thin film loaded in this invention when operating at 2GHz, 6GHz, 10GHz, and 12GHz. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] This invention proposes a dual-polarized tightly coupled dipole antenna with a resistive thin film. By loading a resistive thin film under the dipole and the coupling patch, a resonant structure is introduced in the 9GHz~12GHz frequency band, and the operating bandwidth is extended by utilizing multiple resonant frequency points. A 15:1 (0.8-12GHz) operating bandwidth is achieved through direct coaxial feeding.

[0018] Combination Figure 1 The dual-polarized tightly coupled dipole antenna with a resistive film includes an antenna element comprising a dielectric matching layer 1, a dipole antenna 2, a coupling capacitor patch 3, a metal via 4, a curved slot 5, a resistive film 6, a coaxial feed 7, a metal ground plane 8, a first dielectric substrate 9, a second dielectric substrate 10, and a third dielectric substrate 11. The dipole antenna 2 is symmetrically orthogonally placed and printed on the front and back of the first dielectric substrate 9. The coupling capacitor patch 3 is printed on both sides of the first dielectric substrate. The coaxial feed 7, serving as the antenna's feed structure, passes through the second dielectric substrate 10 and the third dielectric substrate 11 with the resistive film 6 and connects to the dipole antenna 2. The curved slot 5 is located at the end of the dipole antenna 2, and the metal via 4 is embedded inside the first dielectric substrate 9. The dielectric matching layer 1 with a metasurface is placed on top of the dipole antenna 2. The metal ground plane 8 is placed parallel to the antenna along with the dielectric matching layer 1 and the resistive film 6. This invention enables a tightly coupled antenna with dual polarization, low profile, and wide bandwidth design.

[0019] Furthermore, the dielectric matching layer 1, the first dielectric substrate 9, the second dielectric substrate 10, and the third dielectric substrate 11 are made of FR4 material.

[0020] Furthermore, the dipole antenna 2 and the coupling capacitor patch 3 are made of copper.

[0021] Furthermore, the dipole antenna 2, coupling capacitor patch 3, and metal via 4 are printed on a Rogers RO4003 microwave substrate.

[0022] Furthermore, the material of the resistive thin film 6 is a high-resistivity carbon paste.

[0023] Furthermore, the metal through-hole 4 and the metal floor 8 are made of copper.

[0024] Furthermore, the antenna provides a frequency coverage of 0.8~12GHz, the active VSWR of both ports of the dual polarization unit is below 3, the isolation between the two ports is less than -15dB, and it has good radiation characteristics.

[0025] The dielectric substrate is 0.508mm thick Rogers RO4003. The first dielectric substrate has two dipole antennas 2 and two coupling capacitor patches 3 on both sides, with a row of metal vias drilled at the ends of the dipoles. The metal vias and coupling capacitor patches are introduced here to enhance capacitive coupling. The voltage standing wave ratio (VSWR) of this antenna element deteriorates in the low-frequency band, especially with severe impedance mismatch at 2 GHz. By drilling metal vias in the dipole radiating arms, part of the dipole radiating arms are introduced to the back side of the dielectric substrate, and metal patches are loaded on the back side of the dielectric substrate. The metal patches on the front side of the dielectric substrate and the metal patches on the back side of the dielectric substrate form capacitive coupling, effectively extending the length of the dipole radiating arms, thereby improving the VSWR in the low-frequency band. A 2mm thick FR4 is loaded above the antenna. The substrate, acting as a dielectric matching layer, is placed on the aperture surface of the array antenna and parallel to the dielectric cladding. It plays a role in impedance transformation, improving impedance matching between the input impedance and free-space wave impedance of the array antenna and reducing the active reflection coefficient of the elements. However, the voltage standing wave ratio (VSWR) remains high at certain frequencies. Therefore, curved slots are introduced on the antenna's radiating arms to improve some resonant frequencies across the entire operating frequency band. To address the severe mismatch issue of dual-polarized antenna elements at high frequencies (9GHz~12GHz), a layer of FR4 material is added between the dipole antenna and the metal ground plane. The dielectric substrate measures 12.5mm × 12.5mm × 0.44mm. Square and circular high-resistivity carbon paste with a width of 0.825mm is printed on the dielectric substrate to absorb reflected waves from the ground within the antenna's short-circuit resonant bandwidth, thereby widening the antenna's operating bandwidth. Example

[0026] Combination Figures 1-3 An ultra-wideband, low-profile dual-polarized antenna for the 0.8 GHz to 12 GHz frequency range is described, comprising a dielectric matching layer 1, a dipole antenna 2, a coupling capacitor patch 3, a metal via 4, a curved slot 5, a resistive thin film 6, a coaxial feed 7, a metal ground plane 8, a first dielectric substrate 9, a second dielectric substrate 10, and a third dielectric substrate 11. The antenna element size is 12.5 mm × 12.5 mm. The antenna profile height is 33mm (0.088). , (This corresponds to the air wavelength of 0.8 GHz). The FR4 dielectric substrate of the resistive thin film has dimensions of 12.5 mm × 12.5 mm and a thickness of 0.44 mm. A square ring of high-resistivity carbon paste with a side length of 12.5 mm and a width of 0.825 mm is printed on the top of the dielectric substrate.

[0027] like Figure 4 , Figure 5 As shown, the active VSWR of this antenna element is less than 3 in the 0.8~12GHz frequency band, and the isolation between the two ports of this element is less than -15dB in the 0.8~12GHz frequency band.

[0028] like Figure 6 The figure shown is a comparison of the single-line polarization gain and dual-polarization gain of a dual-polarized tightly coupled dipole antenna with a loaded half-resistive frequency selective surface.

[0029] like Figure 7 The images shown are the active radiation patterns of the antenna element at 2GHz, 6GHz, 10GHz, and 12GHz, respectively.

[0030] In summary, this invention presents an ultra-wideband, low-profile dual-polarized dipole antenna designed based on the tight coupling principle, innovatively loaded with a resistive thin film. This antenna can provide a frequency coverage of 0.8–12 GHz. Results show that the active VSWR at both ports of the dual-polarized element is below 3, the isolation between the two ports is less than -15 dB, exhibiting excellent radiation characteristics, and the profile height is only 33 mm (0.088). This antenna features a wide operating bandwidth, a broad beam scanning range, and a low profile height. It is easy to manufacture and can be conformally mounted on curved surfaces, making it significant for practical engineering applications such as electronic reconnaissance and electronic countermeasures.

Claims

1. A dual-polarized tightly coupled dipole ultrawideband antenna with a loaded resistive thin film, characterized in that, The antenna unit includes a dielectric matching layer (1) with a metasurface, a dipole antenna (2), a coupling capacitor patch (3), a metal via (4), a curved slot (5), a resistive film (6), a coaxial feed (7), a metal ground plane (8), a first dielectric substrate (9), a second dielectric substrate (10), and a third dielectric substrate (11); the dielectric matching layer (1) with the metasurface is placed on top of the first dielectric substrate (9); the dipole antenna (2) is symmetrically orthogonally placed and printed on the front and back sides of the first dielectric substrate (9); The coupling capacitor patch (3) is printed on both sides of the first dielectric substrate (9); One antenna arm of the dipole antenna (2) with one polarization direction is placed at the bottom of the first dielectric substrate (9), and the other antenna arm is placed at the top of the first dielectric substrate (9); one antenna arm of the dipole antenna (2) with the other polarization direction is placed at the top of the first dielectric substrate (9), and the other antenna arm is placed at the bottom of the first dielectric substrate (9); four coupling capacitor patches (3) are respectively placed above the end of one antenna arm of the dipole antenna (2) with one polarization direction, below the end of the other antenna arm, and below the end of one antenna arm of the dipole antenna (2) with the other polarization direction. Above the end of another antenna arm; the coaxial feed (7) serves as the antenna feed structure and is connected to the dipole antenna (2) through the second dielectric substrate (10) and the third dielectric substrate (11) loaded with the resistive film (6); the curved slit (5) is opened at the end of the dipole antenna (2); the metal through hole (4) is embedded inside the first dielectric substrate (9) and located at the end of the dipole antenna arm; the metal through hole (4) connects the dipole antenna arm and the coupling capacitor patch (3); the metal ground plane (8) is placed parallel to the antenna with the dielectric matching layer (1) and the resistive film (6).

2. The dual-polarized tightly coupled dipole ultrawideband antenna with a loaded resistive thin film according to claim 1, characterized in that, The dielectric matching layer (1), the first dielectric substrate (9), the second dielectric substrate (10) and the third dielectric substrate (11) are made of FR4.

3. The dual-polarized tightly coupled dipole ultrawideband antenna with a loaded resistive thin film according to claim 1, characterized in that, The dipole antenna (2) and the coupling capacitor patch (3) are made of copper.

4. The dual-polarized tightly coupled dipole ultrawideband antenna with a loaded resistive thin film according to claim 1, characterized in that, The dipole antenna (2), coupling capacitor patch (3) and metal via (4) are printed on Rogers RO4003 microwave substrate.

5. The dual-polarized tightly coupled dipole ultrawideband antenna with a loaded resistive thin film according to claim 1, characterized in that, The material of the resistive thin film (6) is high-resistivity carbon paste.

6. The dual-polarized tightly coupled dipole ultrawideband antenna with a loaded resistive thin film according to claim 1, characterized in that, The metal through-hole (4) and the metal floor (8) are made of copper.

7. The dual-polarized tightly coupled dipole ultrawideband antenna with a loaded resistive thin film according to claim 1, characterized in that, The antenna provides a frequency range of 0.8~12GHz, and the active VSWR of both ports of the dual polarization unit is below 3, with an isolation of less than -15dB between the two ports.

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