Ultra-wideband array antenna unit and finite array antenna

Abstract

The present invention discloses an ultra-wideband array antenna unit and a finite array antenna, belonging to the field of multifunctional broadband integration technology such as communications, radar, and electronic countermeasures. The antenna includes a frequency-selective matching layer, a lumped element matching network, and a floor; the frequency-selective matching layer includes a first dielectric plate; one surface of the first dielectric plate is provided with square metal sheets arranged in a rectangular array; a second dielectric plate and a third dielectric plate are provided directly below the frequency-selective matching layer, and the first dielectric plate, the second dielectric plate, and the third dielectric plate are all parallel to each other; the inner surface of the second dielectric plate and the inner surface of the third dielectric plate are adjacent, and a stripline and a fan-shaped metal sheet group are provided between the two. The present invention can meet the low-cost requirements of ultra-wideband phased arrays and improve the aperture utilization efficiency of ultra-wideband array antennas.

Description

Technical Field

[0001] The present invention relates to the field of multifunctional broadband integration technology such as communications, radar, and electronic countermeasures, and in particular to an ultra-wideband array antenna unit and a limited array antenna. Background Art

[0002] With frequency resources becoming increasingly scarce and demands for functional services constantly increasing, the integration of multiple systems with different frequency bands and functions is an inevitable trend in the development of ultra-wideband equipment. Ultra-wideband array antenna systems meet the frequency expansion requirements of multi-functional integrated equipment.

[0003] Ultra-wideband array systems possess typical functional characteristics, and various designs of ultra-wideband array antennas have emerged. These have developed rapidly in recent years. Initially, ultra-wideband antenna arrays employed a connected array of Vivaldi antennas, as demonstrated in the 2010 IEEE Transactions on Antennas and Propagation article, "UltraWideband All-Metal Flared Notch Array Radiator." These arrays exhibited drawbacks such as a high profile and progressively worsening cross-polarization with increasing scanning angle.

[0004] Later, low-profile tightly coupled dipole antennas emerged. In the 2013 IEEE Transactions on Antennas and Propagation article, "A Wideband, Wide Scanning Tightly Coupled Dipole Array With Integrated Balun (TCDA-IB)," to achieve ultra-wideband, the element spacing is 0.23 wavelengths. To achieve a compromise between element spacing and bandwidth, a two-in-one antenna element design can be used. However, the losses caused by the two-in-one splitting and combining also affect the radiation efficiency of the antenna array.

[0005] Low-profile, tightly coupled dipoles are typically implemented using a Machand balun, as exemplified by the 2019 IEEE Transactions on Antennas and Propagation article, "Dual-Linear Polarized Phased Array With 9:1 Bandwidth and 60° Scanning Off Broadside." This balun design requires a laminated multilayer printed circuit board structure and often uses low-loss materials with a low dielectric constant, such as Er=2.2. This results in high cost and complexity. At the lower end of ultrashort wave frequencies, the increased material costs exacerbate the problem due to the larger array size.

[0006] In patent CN114744409A "A ten-fold frequency-band dual-polarization strongly coupled phased array antenna loaded with resistive material", a resistive frequency selective surface is used, which affects the radiation efficiency.

[0007] For ultra-wideband array antennas, the effect of edge current truncation is inevitable. In the project, the edge port is loaded with a 50-ohm load for virtual element (dummy element) design, and the aperture utilization rate is not high. In patent CN112216980A "A full-aperture strongly coupled ultra-wideband symmetrical dipole phased array antenna", the edge is designed with an extended dipole arm, which has a better effect in the normal direction, but poor effect in the scanning situation. Patent CN114709616A "Ultra-wideband strongly coupled antenna array edge effect suppression method based on amplitude and phase control" provides a method for improving active standing waves in the full scanning state by optimizing the amplitude and phase excitation of the array unit port. Of course, in order to address the performance issues within the instantaneous full bandwidth range, the edge design of the dual-polarization finite array needs to be improved to enhance the instantaneous full-bandwidth reception and radiation capabilities.

[0008] Therefore, low-cost, high-efficiency ultra-wideband array antennas are an urgent need for engineering applications and are of great significance in ultra-wideband phased arrays. Summary of the Invention

[0009] In view of this, the purpose of the present invention is to propose an ultra-wideband array antenna unit and a finite array antenna, which can meet the low-cost requirements of the ultra-wideband phased array and improve the aperture utilization efficiency of the ultra-wideband array antenna.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is:

[0011] An ultra-wideband array antenna unit comprises a frequency selective matching layer, a lumped element matching network and a floor;

[0012] The frequency selective matching layer includes a first dielectric plate; one surface of the first dielectric plate is provided with square metal sheets arranged in a rectangular array;

[0013] A second dielectric plate and a third dielectric plate are provided directly below the frequency selective matching layer, and the first dielectric plate, the second dielectric plate and the third dielectric plate are parallel to each other;

[0014] The inner surface of the second dielectric plate is adjacent to the inner surface of the third dielectric plate, and a strip line and a fan-shaped metal sheet group are provided between the two;

[0015] The outer surfaces of the second dielectric plate and the outer surfaces of the third dielectric plate are both provided with a gradient gap balun; the gradient gap balun comprises a metal plate, with a gradient gap provided in the middle of the metal plate, the gradient gap gradually narrowing from the top to the bottom half of the metal plate; the narrowest end of the gradient gap is further connected to a circular notch for completing the resonant cavity function of the stripline to the gradient gap; triangular notches are further provided on both sides of the gradient gap for achieving ultra-wideband matching in conjunction with the shape of the gradient gap; the fan-shaped metal sheet group comprises a first fan-shaped metal sheet and a second fan-shaped metal sheet; the first fan-shaped metal sheet is located between the projection of the gradient gap and the projection of the triangular notch, and the second fan-shaped metal sheet is located between the projection of the circular notch and the projection of the triangular notch;

[0016] The tip of the first sector-shaped metal sheet and the tip of the second sector-shaped metal sheet are both connected to the feeding port of the strip line;

[0017] The floor is located below the second dielectric plate and the third dielectric plate, and the floor is perpendicular to the second dielectric plate and the third dielectric plate; the other end of the strip line is connected to the lumped element matching network through a microstrip line;

[0018] A fourth dielectric plate is provided between the first and second dielectric plates; the fourth dielectric plate is parallel to the floor; both sides of the metal plate forming the widest position of the gradient gap are provided with corresponding dipole coupling layers; the dipole coupling layers include a top coupling layer and a plane dipole; the top coupling layer is located on the upper surface of the fourth dielectric plate, and the plane dipole is located on the lower surface of the fourth dielectric plate.

[0019] Furthermore, the first sector-shaped metal sheet and the second sector-shaped metal sheet have the same radius and are arranged concentrically.

[0020] Furthermore, the first sector-shaped metal sheet and the second sector-shaped metal sheet are located on the same side of the projection of the gradual gap.

[0021] Furthermore, the feeding port of the stripline is opposite to the narrowest end of the tapered slot, and the stripline extends toward the other side of the tapered slot projection.

[0022] Furthermore, the lumped element matching network includes two inductors and one capacitor, an inductor N and a capacitor O are connected in parallel, and then connected in series with another inductor M to the ground.

[0023] An ultra-wideband finite array antenna comprises a plurality of ultra-wideband array antenna units as described above; every four adjacent antenna units share the same dipole coupling layer; and the angle between the four adjacent antenna units is 90°.

[0024] The beneficial effects of the above technical solution of the present invention are:

[0025] A) This invention provides a tapered slot dipole unit with an element spacing of 0.51 wavelengths at the high-end frequency. Conventional ultra-wideband array antennas use a spacing of 0.2-0.4 wavelengths at the high-end frequency to extend bandwidth. This invention utilizes a large spacing array design. Compared to the tight coupling or two-in-one losses of conventional ultra-wideband array antennas, this reduces the number of channels, improves radiation efficiency, and reduces costs.

[0026] B) All components of the present invention, such as the frequency-selective matching layer, top coupling layer, dual-polarization planar dipole, tapered slot balun, and lumped parameter matching network, are made of common FR4 sheet material. This effectively reduces the cost of the ultra-short wave frequency band array antenna compared to the expensive low-dielectric constant materials used in conventional ultra-wideband array antennas.

[0027] C) The present invention adopts a combined design of a gradient slot balun and a lumped parameter matching network. Compared with the traditional array antenna loaded with resistive materials, it improves the radiation efficiency of the entire frequency band and achieves effective matching of ultra-wideband.

[0028] D) The finite array in the present invention adopts a U-shaped closed design. Compared with conventional array antennas with open edges, it weakens the mutation of edge effects, maintains the symmetry of edge effects, and achieves good performance of instantaneous full bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the structure of the ultra-wideband array antenna unit of the present invention;

[0030] Figure 2 It is a schematic diagram of the connection structure of adjacent antenna units of the present invention;

[0031] Figure 3 yes Figure 2 A top view of

[0032] Figure 4 yes Figure 2 Schematic diagram of the three-dimensional structure;

[0033] Figure 5 It is the active standing wave and efficiency diagram of the ultra-wideband array antenna unit of the present invention;

[0034] Figure 6 It is a stereogram of the ultra-wideband finite array of the present invention.

[0035] Figure 7 It is a top view of the ultra-wideband finite array of the present invention.

[0036] Among them, 1. Square metal sheet, 2. Gradient gap, 3. Triangular hole, 4. Lumped element matching network connection, 5. Microstrip line, 6. Floor, 7. Circular hole, 8. Second fan-shaped metal sheet, 9. Strip line, 10. First fan-shaped metal sheet, 11. Metal plate. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Reference Figure 1 , an ultra-wideband array antenna unit, comprising a frequency-selective matching layer, a lumped element matching network, and a floor;

[0040] The frequency selective matching layer includes a first dielectric plate; one surface of the first dielectric plate is provided with square metal sheets arranged in a rectangular array;

[0041] A second dielectric plate and a third dielectric plate are provided directly below the frequency selective matching layer, and the first dielectric plate, the second dielectric plate and the third dielectric plate are parallel to each other;

[0042] The inner surface of the second dielectric plate is adjacent to the inner surface of the third dielectric plate, and a strip line and a fan-shaped metal sheet group are provided between the two;

[0043] The outer surfaces of the second dielectric plate and the outer surfaces of the third dielectric plate are both provided with a gradient gap balun; the gradient gap balun comprises a metal plate, with a gradient gap provided in the middle of the metal plate, the gradient gap gradually narrowing from the top to the bottom half of the metal plate; the narrowest end of the gradient gap is further connected to a circular notch for completing the resonant cavity function of the stripline to the gradient gap; triangular notches are further provided on both sides of the gradient gap for achieving ultra-wideband matching in conjunction with the shape of the gradient gap; the fan-shaped metal sheet group comprises a first fan-shaped metal sheet and a second fan-shaped metal sheet; the first fan-shaped metal sheet is located between the projection of the gradient gap and the projection of the triangular notch, and the second fan-shaped metal sheet is located between the projection of the circular notch and the projection of the triangular notch;

[0044] The tip of the first sector-shaped metal sheet and the tip of the second sector-shaped metal sheet are both connected to the feeding port of the strip line;

[0045] The floor is located below the second dielectric plate and the third dielectric plate, and the floor is perpendicular to the second dielectric plate and the third dielectric plate; the other end of the strip line is connected to the lumped element matching network through a microstrip line;

[0046] A fourth dielectric plate is provided between the first and second dielectric plates; the fourth dielectric plate is parallel to the floor; both sides of the metal plate forming the widest position of the gradient gap are provided with corresponding dipole coupling layers; the dipole coupling layers include a top coupling layer and a plane dipole; the top coupling layer is located on the upper surface of the fourth dielectric plate, and the plane dipole is located on the lower surface of the fourth dielectric plate.

[0047] Furthermore, the first sector-shaped metal sheet and the second sector-shaped metal sheet have the same radius and are arranged concentrically.

[0048] Furthermore, the first sector-shaped metal sheet and the second sector-shaped metal sheet are located on the same side of the projection of the gradual gap.

[0049] Furthermore, the feeding port of the stripline is opposite to the narrowest end of the tapered slot, and the stripline extends toward the other side of the tapered slot projection.

[0050] Furthermore, the lumped element matching network includes two inductors and one capacitor, an inductor N and a capacitor O are connected in parallel, and then connected in series with another inductor M to the ground.

[0051] Reference Figures 2 to 4 and Figure 6 、 Figure 7 An ultra-wideband finite array antenna comprises a plurality of ultra-wideband array antenna units as described above; every four adjacent antenna units share the same dipole coupling layer; and the angle between two adjacent antenna units is 90°.

[0052] The following is a more detailed embodiment:

[0053] In this embodiment, the frequency selective matching layer, top coupling layer, dual-polarization planar dipole, gradient slot balun, and lumped parameter matching network are all made of common board material FR4, achieving low-cost application in the ultra-short wave frequency band.

[0054] The top coupling layer adopts a planar design, which can easily meet the electrical continuity requirements when the sub-array is modularized and facilitate the planar operation of sub-array disassembly and assembly.

[0055] The dual-polarization planar dipole and the tapered slot balun adopt a metal connection design to form a new type of tapered slot dipole, which achieves a half-wavelength spacing greater than the high-end frequency, reduces the number of channels, and lowers the cost of the ultra-wideband array system.

[0056] The combined optimization design of the gradient slot balun and the lumped parameter matching network in the present invention achieves good matching of the ultra-wideband 9 octaves without using resistive materials, thereby improving the radiation efficiency of the entire frequency band.

[0057] The finite array uses a combination of 8x9 dual-polarized cells in a U-shaped closed array configuration. This maintains the symmetry of the current at the edges of the finite array and reduces the sudden change in the opening at the edges of the conventional 8x8 dual-polarized cell L-shaped combination. A set of amplitude and phase feed weighting parameters is then applied to all ports to achieve excellent performance across the instantaneous full bandwidth.

[0058] From top to bottom, the UWB array antenna element consists of a frequency-selective matching layer, a top coupling layer, a dual-polarization planar dipole, a tapered slot balun, a lumped parameter matching network, and a floor. The shape of the UWB array antenna element is designed based on a combination of parameters, including the element height (B), the coupling slot depth (E), the widest dimension (D) of the tapered slot, the narrowest dimension (H) of the tapered slot, and the exponential curvature (P) of the tapered slot. The values ​​of these parameters are detailed in Table 1.

[0059] The frequency-selective matching layer consists of multiple square metal blocks arranged on a 0.254mm thick FR4 substrate. The top coupling layer and planar dipoles are composed of two metal layers, distributed on the top and bottom surfaces of a 0.508mm thick FR4 substrate. The top coupling layer is a circular metal sheet, while the dual-polarization planar dipoles are diagonal diamond-shaped and connected to the tapered-slot balun via metal supports. The top coupling metal provides contact between subarrays.

[0060] The tapered-slot balun consists of three metal layers and two layers of 1mm-thick FR4 dielectric. The lumped-parameter matching network consists of capacitors and inductors. The tapered slot gradually narrows, connecting a planar dipole at its widest point and using a stripline coupling feed at its narrowest point. The stripline coupling feed consists of two parallel-connected sets of sector-shaped metal sheets at one end, and the other end is converted from a stripline to a microstrip line, connecting to the lumped-element matching network.

[0061] The lumped element matching network consists of two inductors and one capacitor. An inductor N is connected in parallel with a capacitor O, and then connected in series with another inductor M to ground.

[0062] The finite array includes ultra-wideband array antenna elements that are combined into a closed-mouth 8*9 finite sub-array at a frequency greater than half a wavelength at the high end of the frequency range. This is then fed using a set of instantaneous full-bandwidth amplitude and phase signals, achieving the excellent effect of full-aperture, full-port, and full-bandwidth finite array performance.

[0063] The width A of the array element, the height B of the unit, the height C of the frequency-selective metal sheet, the widest dimension D of the tapered slot, the depth E of the coupling slot, the length F of the stripline coupling fan-shaped piece, the diameter G of the circular cavity for coupling feed, the narrowest dimension H of the tapered slot, the coupling width I of the stripline, the width J of the microstrip line, the diameter K of the top coupling patch, the length L of the planar dipole, the lumped element capacitance O, the inductance M and N, and the exponential curvature P of the tapered slot.

[0064] The frequency-selective matching layer is realized by a 0.254mm thick FR4 printed circuit board, and multiple groups of metal blocks are periodically etched on the surface to improve the matching of spatial impedance.

[0065] The top coupling layer and the dual-polarization planar dipole are realized by a 0.508mm thick FR4 printed circuit board. The top coupling layer is a metal circle, which couples the dual-polarization horizontal dipole and expands the working bandwidth.

[0066] The dual-polarization planar dipoles and the tapered-slot balun are electrically connected via metal support screws. The subarrays are connected via top-coupled metal discs for contact-type interconnection, facilitating the engineering of modular subarrays.

[0067] The gradient-slot balun is constructed by laminating two layers of 1mm-thick FR4 printed circuit board. It consists of three metal layers, the top and bottom layers of which feature gradient slots and are connected via metalized vias to achieve ultra-wideband impedance matching. The middle layer features a stripline-coupled feed design, with one end of the stripline connected to two sets of sector-shaped metal sheets and the other end to a microstrip transition section. Metalized vias maintain ground current continuity at the transition between the stripline and microstrip lines.

[0068] The lumped parameter matching network is designed on the microstrip line to further improve the matching effect at the low end of the frequency. The lumped parameter matching network consists of an inductor and a capacitor connected in parallel, and then connected in series with an inductor. The active standing wave and efficiency diagram of the antenna unit can be referred to as Figure 5 .

[0069] The finite array is a closed U-shaped array consisting of 8x9 horizontally polarized elements and 9x8 vertically polarized elements. The horizontal and vertical spacings dx and dy are identical, both equal to the element width A, achieving a large spacing greater than half a wavelength at high-end frequencies. Furthermore, a set of amplitude- and phase-weighted excitation feeds is used to improve the reflection coefficient at the edge ports and enhance the radiation efficiency of the entire aperture.

[0070] Table 1 Ultra-wideband array antenna unit parameter values

[0071]

Claims

1. An ultra-wideband array antenna unit, characterized in that: Includes frequency-selective matching layers, lumped element matching networks, and floorboards; The frequency selective matching layer includes a first dielectric plate; one surface of the first dielectric plate is provided with square metal sheets arranged in a rectangular array; A second dielectric plate and a third dielectric plate are provided directly below the frequency selective matching layer, and the first dielectric plate, the second dielectric plate and the third dielectric plate are parallel to each other; The inner surface of the second dielectric plate is adjacent to the inner surface of the third dielectric plate, and a strip line and a fan-shaped metal sheet group are provided between the two; The outer surfaces of the second dielectric plate and the outer surfaces of the third dielectric plate are both provided with a gradient gap balun; the gradient gap balun comprises a metal plate, with a gradient gap provided in the middle of the metal plate, the gradient gap gradually narrowing from the top to the bottom half of the metal plate; the narrowest end of the gradient gap is further connected to a circular notch for completing the resonant cavity function of the stripline to the gradient gap; triangular notches are further provided on both sides of the gradient gap for achieving ultra-wideband matching in conjunction with the shape of the gradient gap; the fan-shaped metal sheet group comprises a first fan-shaped metal sheet and a second fan-shaped metal sheet; the first fan-shaped metal sheet is located between the projection of the gradient gap and the projection of the triangular notch, and the second fan-shaped metal sheet is located between the projection of the circular notch and the projection of the triangular notch; The tip of the first sector-shaped metal sheet and the tip of the second sector-shaped metal sheet are both connected to the feeding port of the strip line; The floor is located below the second dielectric plate and the third dielectric plate, and the floor is perpendicular to the second dielectric plate and the third dielectric plate; the other end of the strip line is connected to the lumped element matching network through a microstrip line; A fourth dielectric plate is provided between the first and second dielectric plates; the fourth dielectric plate is parallel to the floor; both sides of the metal plate forming the widest position of the gradient gap are provided with corresponding dipole coupling layers; the dipole coupling layers include a top coupling layer and a plane dipole; the top coupling layer is located on the upper surface of the fourth dielectric plate, and the plane dipole is located on the lower surface of the fourth dielectric plate.

2. The ultra-wideband array antenna unit according to claim 1, wherein: The first sector-shaped metal sheet and the second sector-shaped metal sheet have the same radius and are arranged concentrically.

3. The ultra-wideband array antenna unit according to claim 1, wherein: The first sector-shaped metal sheet and the second sector-shaped metal sheet are located on the same side of the projection of the gradual gap.

4. The ultra-wideband array antenna unit according to claim 1, wherein: The feeding port of the strip line faces the narrowest end of the tapered slot, and the strip line extends toward the opposite side of the tapered slot projection.

5. The ultra-wideband array antenna unit according to claim 1, characterized in that: The lumped element matching network includes two inductors and one capacitor, wherein an inductor N and a capacitor O are connected in parallel and then connected in series with another inductor M to the ground.

6. An ultra-wideband finite array antenna, characterized in that: The invention comprises a plurality of ultra-wideband array antenna units according to any one of claims 1 to 5; every four adjacent antenna units share the same dipole coupling layer; and the angle between two adjacent antenna units is 90°.

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