Antenna unit and array antenna composed of antenna units

Abstract

The embodiment of the invention discloses an antenna unit and an array antenna formed by the antenna unit, relates to the technical field of antennas, and aims to solve the problem that an antenna structure in the prior art is difficult to meet the broadband requirement. The second dielectric substrate and the bent first dielectric substrate form a basic structure conformal with the carrier, the microstrip monopole strip is arranged to increase a current path on the surface of the patch, miniaturization and broadband of the antenna are achieved, the antenna function is achieved through microstrip feeder feeding, on one hand, due to the fact that the parasitic strips are arranged on the two sides of the microstrip feeder, on the other hand, the parasitic strips are arranged on the two sides of the microstrip feeder; on one hand, a form similar to a sleeve antenna can be formed, the high-frequency bandwidth of the antenna is effectively improved, on the other hand, a wave absorbing material layer is arranged on the back face of the dielectric substrate and used for absorbing reflection current, reducing the standing-wave ratio of the antenna, improving the bandwidth of the antenna and meeting the broadband requirement of the antenna.

Description

Technical Field

[0001] This application relates to the field of antenna technology, and particularly to an antenna element and an array antenna composed of such antenna elements. Background Art

[0002] Antennas are widely used in radio systems such as communication, broadcasting, television, radar, and navigation. They play a role in propagating radio waves and are essential devices for effectively radiating and receiving radio waves. An array antenna is a special type of antenna composed of at least two antenna elements arranged regularly or randomly and obtaining a predetermined radiation characteristic through appropriate excitation. However, the current antenna structure is relatively complex, not easy to conform to the carrier, and difficult to meet the broadband requirements in new airborne communication, radar, or countermeasure systems. Summary of the Invention

[0003] The main purpose of this application is to provide an antenna element and an array antenna composed of such antenna elements, aiming to solve the problem that the antenna structure in the prior art is difficult to meet the broadband requirements.

[0004] To achieve the above objective, the technical solutions adopted in the embodiments of this application are as follows:

[0005] In a first aspect, an embodiment of this application provides an antenna element, including:

[0006] A dielectric substrate, which includes a first dielectric substrate and a second dielectric substrate. The first dielectric substrate is bent to form a first section of the substrate and a second section of the substrate;

[0007] A microstrip monopole strip, which is disposed on the first surface of the first dielectric substrate;

[0008] A microstrip feeder, which is disposed on the first surface of the second section of the substrate. One end of the microstrip feeder is connected to the microstrip monopole strip;

[0009] Parasitic strips, which are disposed on the first surface of the second section of the substrate and symmetrically disposed on both sides of the microstrip feeder;

[0010] An absorbing material layer, which is disposed on the second surface of the dielectric substrate.

[0011] In a possible implementation manner of the first aspect, the microstrip monopole strip is octagonal and symmetric about the bending seam of the first dielectric substrate.

[0012] In a possible implementation manner of the first aspect, the microstrip monopole strip is an annular strip.

[0013] In a possible implementation manner of the first aspect, the shape of the parasitic strip is strip-shaped, triangular, or semi-circular.

[0014] In a possible implementation of the first aspect, the microstrip feeder is a stepped feeder.

[0015] In a possible implementation of the first aspect, an antenna feeding patch structure is provided on the first surface of the second dielectric substrate, and the antenna feeding patch structure employs a microstrip-to-slotline balun.

[0016] In a possible implementation of the first aspect, the antenna feeding patch structure is a Vivaldi antenna.

[0017] In a possible implementation of the first aspect, a defective metal floor is provided on the first surface of the second substrate segment.

[0018] In a possible implementation of the first aspect, the defective metal floor is disposed under the microstrip feeder.

[0019] In a second aspect, an embodiment of the present application provides an array antenna, including a plurality of antenna units arranged in an array as provided in any one of the above first aspects.

[0020] Compared with the prior art, the beneficial effects of the present application are as follows:

[0021] An antenna unit proposed in an embodiment of the present application and an array antenna composed of the antenna units form a conformal basic structure with a carrier through a second dielectric substrate and a bent first dielectric substrate, and a microstrip monopole strip is provided to increase the patch surface current path, realizing miniaturization and broadband of the antenna. The antenna function is realized through microstrip feeder feeding. On the one hand, since parasitic strips are provided on both sides of the microstrip feeder, a form similar to a sleeve antenna can be formed, effectively improving the high-frequency bandwidth of the antenna. On the other hand, an absorbing material layer is also provided on the back of the dielectric substrate to absorb the reflected current, reduce the antenna standing wave ratio, improve the bandwidth of the antenna, and meet the broadband requirements of the antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of the antenna unit provided by an embodiment of the present application;

[0023] Figure 2 is a front view structural diagram of the antenna unit provided by an embodiment of the present application;

[0024] Figure 3 is a side view structural diagram of the antenna unit provided by an embodiment of the present application;

[0025] Figure 4 is a schematic structural diagram of the antenna unit provided by an embodiment of the present application employing a semi-circular parasitic strip;

[0026] Figure 5 is a schematic structural diagram of the antenna unit provided by an embodiment of the present application employing a triangular parasitic strip;

[0027] Figure 6 Schematic diagram of the structure of the array antenna provided by the embodiment of the present application;

[0028] Figure 7 Comparison chart of the standing wave ratios of the array antenna provided by the embodiment of the present application before and after the parasitic strip is set;

[0029] Figure 8 Schematic diagram of the active standing wave results of each unit of the 1*8 linear array of the array antenna provided by the embodiment of the present application when scanning at 0 degrees of vertical polarization;

[0030] Figure 9 Schematic diagram of the active standing wave results of each unit of the 1*8 linear array of the array antenna provided by the embodiment of the present application when scanning at 0 degrees of horizontal polarization;

[0031] Figure 10 Comparison chart of the monostatic RCS of the array antenna provided by the embodiment of the present application before and after being hollowed out;

[0032] Figure 11 Patterns of the 1*8 linear array of the array antenna provided by the embodiment of the present application at different scanning angles when f0GHz;

[0033] Description of the reference numerals in the drawings:

[0034] 1 - dielectric substrate, 2 - microstrip monopole strip, 3 - defective metal floor, 4 - parasitic strip, 5 - absorbing material layer, 6 - antenna feeding patch structure, 7 - microstrip feeder, 8 - microstrip line to slot line balun. Detailed implementation manners

[0035] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0036] It should be noted that all the directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0037] In this application, unless otherwise clearly defined and limited, terms such as "connection" and "fixation" shall be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of this application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0039] Antennas are widely used in radio systems such as communication, broadcasting, television, radar, and navigation, playing the role of propagating radio waves and being an essential device for effectively radiating and receiving radio waves. An array antenna is a special type of antenna composed of at least two antenna elements arranged regularly or randomly and obtaining a predetermined radiation characteristic through appropriate excitation. However, the current antenna structure is relatively complex, not easy to conform to the carrier, and difficult to meet the requirements for broadband in new airborne communication, radar, or countermeasure systems.

[0040] For example, in the patent application with the application number 202211651591.X and the name of a small dual-polarized ultra-wideband array antenna device based on an aircraft carrier, a four-ridge horn antenna with an open metal structure is used and deformed, having good bandwidth, polarization isolation, and symmetry of radiation characteristics. However, its structure is relatively complex and not easy to conform to the carrier, and the proportion of metal materials is too large, the profile is relatively high, and the scattering performance is poor.

[0041] Another example is the patent application with the application number 202310857432.3 and the name of an anti-heel Vivaldi antenna loaded with a parasitic structure, which also has certain low-scattering characteristics. However, this antenna (array) is a single-polarized antenna and cannot achieve two orthogonal polarizations simultaneously.

[0042] Based on the problems of the existing technology, in order to further expand the bandwidth of the array antenna, realize the miniaturization and low scattering of the antenna, and meet the requirements of broadband, high gain, beam scanning, and low scattering in new airborne communication, radar, or countermeasure systems, the embodiment of the present application provides an antenna element, as shown in the attached Figure 1 - attached Figure 5 figure, which includes: a dielectric substrate 1, a microstrip monopole strip 2, a microstrip feeder 7, parasitic strips 4, and an absorbing material layer 5, where: the dielectric substrate 1 includes a first dielectric substrate and a second dielectric substrate, and the first dielectric substrate is bent to form a first section of the substrate and a second section of the substrate; the microstrip monopole strip 2 is disposed on the first surface of the first dielectric substrate; the microstrip feeder 7 is disposed on the first surface of the second section of the substrate, and one end of the microstrip feeder 7 is connected to the microstrip monopole strip 2; the parasitic strips 4 are disposed on the first surface of the second section of the substrate and are symmetrically disposed on both sides of the microstrip feeder 7; the absorbing material layer 5 is disposed on the second surface of the dielectric substrate 1.

[0043] In this embodiment, a conformal basic structure with the carrier is formed by the second dielectric substrate and the bent first dielectric substrate. The microstrip monopole strip 2 is provided to increase the surface current path of the patch, realizing the miniaturization and broadband of the antenna. The antenna function is realized by feeding through the microstrip feeder 7. On the one hand, since parasitic strips 4 are provided on both sides of the microstrip feeder 7, a form similar to a sleeve antenna can be formed, effectively improving the high-frequency bandwidth of the antenna. On the other hand, an absorbing material layer 5 is also provided on the back surface of the dielectric substrate 1 to absorb the reflected current, reduce the antenna standing wave ratio, improve the bandwidth of the antenna, and meet the broadband requirements of the antenna.

[0044] It should be noted that the first surface and the second surface described in the embodiment of the present application can be respectively understood as the working surface and the back surface, that is, the surface facing upward in the attached figure is the first surface, and the surface facing downward is the second surface. Overall, the antenna element is in three sections, and the bent section of the dielectric substrate 1 is parallel to the independent second dielectric substrate, making the antenna laterally present a Z-shaped structure similar to that shown in the attached Figure 3 figure. By designing the folded antenna element, it can be applied under conditions where space is limited and is suitable for airborne applications.

[0045] By attaching an absorbing material to the back of the dielectric substrate 1 to form the absorbing material layer 5, common absorbing materials such as carbon-based absorbing materials, ferrite absorbing materials, alloy absorbing materials, and carbon fiber absorbing materials, etc. When the antenna is working, especially in the high-frequency band, due to the mismatch between the antenna and the feeder system, reflected currents may be generated. These reflected currents will not only reduce the radiation efficiency of the antenna but may also cause electromagnetic interference to surrounding electronic devices. The absorbing material can effectively absorb these reflected currents and convert them into heat energy or other forms of energy to dissipate, thereby reducing the impact on the antenna performance.

[0046] The Voltage Standing Wave Ratio (VSWR) is an important parameter for measuring the matching degree between an antenna and a feeder system. A high VSWR means a large reflected power and a decline in antenna performance. By reasonably arranging absorbing materials in the antenna system, the matching between the antenna and the feeder can be optimized, the reflected power can be reduced, and thus the VSWR can be decreased, which helps to improve the radiation efficiency and bandwidth of the antenna. Another important role of absorbing materials in antenna design is to increase the bandwidth of the antenna. By adjusting the characteristic parameters of the absorbing materials (such as thickness, conductivity, permeability, etc.), the absorption and regulation of electromagnetic waves in different frequency bands can be achieved. In this way, the antenna can maintain good performance in different frequency bands, thereby broadening its operating bandwidth.

[0047] As shown in the Figure 1 attachment, strip-shaped metal parasitic patches, namely parasitic strips 4, are loaded equidistantly on both sides of the microstrip feeder 7 provided on the dielectric substrate 1. The purpose is to enhance the coupling with the feeder. After introducing two coupling capacitors, the operating frequency band of the antenna can be expanded to complete the miniaturization design of the antenna. The shape of the parasitic strip 4 is not limited to the strip shape shown in the Figure 1 attachment, and can also be a semicircular shape as shown in the Figure 4 attachment, or a triangular shape as shown in the Figure 5 attachment, as long as energy coupling can be generated with the microstrip feeder 7.

[0048] In one embodiment, as shown in the Figure 1 attachment, the microstrip monopole strip 2 is octagonal and the microstrip monopole strip 2 is symmetric about the bending slit of the first dielectric substrate. In the above implementation, with the bending slit of the first dielectric substrate as the axis of symmetry, the microstrip monopole strip 2 is symmetrically printed on the dielectric substrate 1, and the four corners of the conventional metal strip are trimmed so that its outer contour is octagonal, which can effectively increase the patch surface current path under the same size and achieve the miniaturization and broadband of the antenna. In order to further reduce the RCS of the antenna, the part with weak current of the microstrip monopole strip 2 is hollowed out and designed as an annular strip, which can reduce the metal area with less impact on the electrical performance.

[0049] In one embodiment, as shown in the Figure 2 attachment, the microstrip feeder 7 is designed as a stepped feeder. In this embodiment of the application, it is a three-stage one. It can be seen from the attached drawing that the width of the microstrip feeder 7 has a stepped contraction from top to bottom and is divided into three sections. The purpose is to increase the current path while realizing the impedance transition from the feeding port to the radiation patch, which can effectively improve the bandwidth.

[0050] In one embodiment, as shown in the Figure 1As shown, an antenna feed patch structure 6 is provided on the first surface of the second dielectric substrate. The antenna feed patch structure 6 adopts a microstrip-to-slotline balun. The λ / 4 microstrip fan-shaped stub design at the end of the microstrip line and the λ / 4 slotline circular stub extend the bandwidth to a certain extent, where λ is the signal wavelength. The main function of the microstrip-to-slotline balun is to achieve the conversion between the microstrip line transmission mode and the slotline transmission mode. This conversion is crucial for ensuring the effective transmission of signals between two different transmission lines. Since the characteristic impedances of the microstrip line and the slotline are different, direct connection will cause signal reflection and loss. The microstrip-to-slotline balun realizes impedance matching between the two transmission lines through a specific structural design, thereby improving the signal transmission efficiency.

[0051] In one embodiment, as shown in the appendix Figure 1 As shown, the antenna feed patch structure 6 is a Vivaldi antenna. The working principle of the Vivaldi antenna is based on the movement of the feed point and the involute arrangement of the metal sheets. When current flows through the metal sheets, the interaction between the electric field and the magnetic field will be generated between the metal sheets. This interaction causes electromagnetic waves to radiate in front of the antenna, realizing signal transmission and reception. The involute arrangement of the metal sheets enables the electrical signal to propagate in the antenna in multiple frequency bands, thereby endowing the Vivaldi antenna with broadband characteristics. The interaction between the electric field and the magnetic field forms a radiation field. When current passes through the metal sheets, electromagnetic waves radiate outward to realize signal transmission. At the same time, the antenna can also receive electromagnetic wave signals from the outside.

[0052] In one embodiment, as shown in the appendix Figure 1 As shown, a defected metal floor 3, that is, a defected ground structure (DGS), is provided on the first surface of the second substrate. It refers to a circuit structure that etches "defects" on the metal ground plane at the bottom of the microwave circuit to change the current distribution on the ground plane, so that the entire microwave circuit exhibits band-stop characteristics at a specific frequency band, thereby changing the electromagnetic characteristics of the circuit. This structure can be used to achieve functions such as filtering, coupling, and impedance matching. The defected metal floor 3 can be directly disposed under the microstrip feeder or coplanar waveguide. By designing the geometric shape of the defect, appropriate perturbation can be generated on the ground plane for the current distribution to achieve the desired electromagnetic effect. While achieving better impedance characteristics of the antenna, the defected ground structure reduces the metal area compared with the traditional complete ground structure, which is beneficial to the realization of low-scattering characteristics.

[0053] As shown in the appendix Figure 6As shown in the figure, based on the same inventive concept as the foregoing embodiments, an embodiment of the present application further provides an array antenna, which includes a plurality of antenna units provided in the embodiments of the present application arranged in an array. The array scale of the antenna units is continuously expanded along the array direction to continuously improve the gain of the array antenna, and the maximum radiation direction can be changed by the feeding phase between the units to achieve beam scanning ability. The antenna has a small size, which is conducive to forming an array to achieve beam scanning; it has a low profile, which is beneficial to conformal with the surface of the installation platform, and can be applied to broadband radar and communication fields to meet the requirements of new airborne communication, radar or countermeasure systems for broadband, high gain, beam scanning, and low scattering.

[0054] The array antenna of the embodiment of the present application is composed of antenna units with parasitic strips 4 added, which expands the bandwidth to 0.520f0 - 2.193f0 GHz. It has a small size, and the element width is only 31.25% of the maximum wavelength λ of the working frequency band. L It has a low profile, and the element height is only 28.1% of the maximum wavelength λ of the working frequency band. L The metal area of the vertically polarized unit is small, only 19.25% of the area of the dielectric substrate, which is convenient for forming an array and applying it to the low-scattering field. As shown in the appendix Figure 7 As shown in the figure, it is a comparison diagram of the standing wave ratio before and after loading the parasitic strip 4. The folded microstrip monopole unit with the parasitic strip 4 loaded is compared with the folded microstrip monopole unit. Taking the standing wave ratio less than 3 as the standard, the working bandwidth of the folded microstrip monopole unit with the parasitic strip 4 loaded is 0.320f0 - 3.493f0 GHz, and the working bandwidth of the folded microstrip monopole unit is 0.333f0 - 2.320f0 GHz.

[0055] As shown in the appendix Figure 8 As shown in the figure, it is a schematic diagram of the active standing wave results of each unit of a 1*8 linear array scanning 0-degree vertical polarization. The working bandwidth of the antenna is 0.327f0 - 2.193f0 GHz and 2.973f0 - 3.327f0 GHz, and the active standing wave ratio is less than 3. As shown in the appendix Figure 9 As shown in the figure, it is a schematic diagram of the active standing wave results of each unit of a 1*8 linear array scanning 0-degree horizontal polarization. The working bandwidth of the antenna is 0.520f0 - 3.487f0 GHz, and the active standing wave ratio is less than 3.

[0056] As shown in the appendix Figure 10 As shown in the figure, it is a comparison diagram of the monostatic RCS before and after the array antenna is hollowed out. After the hollowed-out design, that is, designed as a circular strip shape, the unit RCS is reduced by about 10 dB at the peak, effectively reducing the scattering. As shown in the appendix Figure 11 As shown in the figure, it is the radiation pattern of a 1*8 linear array at different scanning angles at f0 GHz. The maximum gain of the antenna at 0° scanning is 7.57 dBi, and the maximum gain at 48° scanning is 6.05 dBi.

[0057] It should be noted that in this article, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article or system comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or elements inherent to such process, method, article or system. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, article or system comprising such element.

[0058] The serial numbers of the embodiments of the present application above are only for description and do not represent the superiority or inferiority of the embodiments.

[0059] In summary, an antenna unit and an array antenna composed of the antenna unit proposed in the embodiments of the present application. The antenna unit includes: a dielectric substrate, a microstrip monopole strip, a microstrip feeder, a parasitic strip and an absorbing material layer, wherein: the dielectric substrate includes a first dielectric substrate and a second dielectric substrate, and the first dielectric substrate is bent to form a first section of the substrate and a second section of the substrate; the microstrip monopole strip is disposed on the first surface of the first dielectric substrate; the microstrip feeder is disposed on the first surface of the second section of the substrate, and one end of the microstrip feeder is connected to the microstrip monopole strip; the parasitic strip is disposed on the first surface of the second section of the substrate and is symmetrically disposed on both sides of the microstrip feeder; the absorbing material layer is disposed on the second surface of the dielectric substrate. The present application forms a conformal basic structure with the carrier through the second dielectric substrate and the bent first dielectric substrate, sets the microstrip monopole strip to increase the surface current path of the patch, realizes the miniaturization and broadband of the antenna, and realizes the antenna function through the microstrip feeder for feeding. On the one hand, since parasitic strips are disposed on both sides of the microstrip feeder, a form similar to a sleeve antenna can be formed, effectively improving the high-frequency bandwidth of the antenna. On the other hand, an absorbing material layer is also disposed on the back surface of the dielectric substrate to absorb the reflected current, reduce the antenna standing wave ratio, improve the bandwidth of the antenna, and meet the broadband requirements of the antenna.

[0060] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An antenna unit, characterized in that: include: A dielectric substrate, the dielectric substrate comprising a first dielectric substrate and a second dielectric substrate, the first dielectric substrate being bent to form a first section substrate and a second section substrate; A microstrip monopole strip, wherein the microstrip monopole strip is arranged on the first surface of the first dielectric substrate; A microstrip feed line, the microstrip feed line being arranged on the first surface of the second section substrate, one end of the microstrip feed line being connected to the microstrip monopole strip; A parasitic strip, the parasitic strip being arranged on the first surface of the second section substrate and symmetrically arranged on both sides of the microstrip feed line; The wave absorbing material layer is arranged on the second surface of the dielectric substrate.

2. The antenna unit according to claim 1, characterized in that The microstrip monopole strip is octagonal and symmetrical about the bending seam of the first dielectric substrate.

3. The antenna unit according to claim 1, characterized in that The microstrip monopole strip is a ring-shaped strip.

4. The antenna unit according to claim 1, characterized in that The parasitic strip is in the shape of a strip, a triangle or a semicircle.

5. The antenna unit according to claim 1, characterized in that The microstrip feed line is a stepped feed line.

6. The antenna unit according to claim 1, characterized in that An antenna feeding patch structure is arranged on the first surface of the second dielectric substrate, and the antenna feeding patch structure adopts a microstrip line-to-slot line balun.

7. The antenna unit according to claim 6, characterized in that The antenna feed patch structure is a Vivaldi antenna.

8. The antenna unit according to claim 1, characterized in that A defective metal floor is arranged on the first surface of the second section substrate.

9. The antenna unit according to claim 8, characterized in that The defective metal floor is arranged at the lower layer of the microstrip feeder.

10. An array antenna, characterized in that: The invention comprises a plurality of antenna units according to any one of claims 1 to 9 arranged in an array.

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