Compact ultra-wide-angle scanning antenna array based on adjustable unit directional diagram

Abstract

The invention discloses a compact ultra-wide-angle scanning antenna array based on an adjustable unit directional diagram. Based on the superposition principle of dipole and monopole directional diagrams included in the antenna unit, unit directional diagram deflection is realized, and unit gain at an unexpected angle is reduced. Based on unit pattern deflection, array large scanning angle gain is improved, and wide-angle scanning can be realized; due to the fact that the unexpected angle unit gain is low, array low sidelobe scanning can be achieved. According to the invention, the unit structure is compact, the feed structure is simple, and the side lobe level of the array at a large scanning angle is significantly reduced while the wide-angle scanning capability is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of radar antennas, and in particular relates to a compact ultra-wide angle scanning antenna array based on adjustable unit radiation patterns. Background Art

[0002] As airborne radar, vehicle-mounted anti-collision radar and mobile communications gradually increase their demand for wide-area beam coverage, ultra-wide-angle scanning antennas are receiving much attention from academia and industry. However, conventional phased array antennas are difficult to achieve wide-angle scanning due to factors such as unit radiation patterns, mutual coupling and matching between units. The scanning range is usually within ±60°, and the gain attenuation is severe as the scanning angle increases (gain attenuation of 3~4dB when scanning to ±60°). This will lead to problems such as limited radar detection range and narrow coverage of communication base stations.

[0003] The existing wide-angle scanning arrays with adjustable directivity patterns generally have a complex structure and mostly use multi-layer dielectrics, which leads to high array cost and processing complexity. There is also a lack of research on how to improve the gain at large scanning angles and suppress the sidelobe level of the array at large scanning angles. Therefore, how to achieve both gain improvement and sidelobe suppression at large scanning angles based on a single-layer dielectric is a technical problem that needs to be solved urgently. Summary of the invention

[0004] To solve the above technical problems, the present invention provides a compact ultra-wide-angle scanning antenna array based on adjustable unit pattern, which only includes a single layer of medium, and achieves gain enhancement and sidelobe suppression at large scanning angles based on adjustable unit pattern and unit pattern gain control technology.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A compact ultra-wide angle scanning antenna array based on adjustable unit directional pattern includes a dielectric substrate and a plurality of directional pattern adjustable units with the same structure, each directional pattern adjustable unit includes a feed line, a bent dipole, a left monopole, a right monopole, a first DC bias line, a second DC bias line, a first diode loaded by the left monopole, a second diode loaded by the right monopole, a first metallized through hole, a fifth metallized through hole, a second metallized through hole, a third metallized through hole, a fourth metallized through hole, a sixth metallized through hole and a metal ground, wherein: The left monopole and the right monopole are symmetrically distributed on the upper surface of the dielectric substrate, and the metal ground is located on the lower surface of the dielectric substrate; The first DC bias line is connected to the end of the left monopole and is used to control the on-off of the first diode, and the first DC bias line is connected to the metal ground through the first metallized through hole; the second DC bias line is connected to the end of the right monopole and is used to control the on-off of the second diode, and the second DC bias line is connected to the metal ground through the fifth metallized through hole; The first dipole arm and the second dipole arm of the bent dipole are directly connected to the metal ground, the metal microstrip line of the bent dipole is located on the upper surface of the dielectric substrate and is connected to the first dipole arm through the second metallized through hole, and the first dipole arm is connected to the feeder line on the upper surface of the dielectric substrate through the third metallized through hole; The left monopole and the right monopole are connected to the metal ground through a fourth metallized through hole and a sixth metallized through hole respectively.

[0006] The beneficial effects of the present invention are: (1) The present invention proposes a unit pattern reconfigurable unit with controllable regional gain, which can not only realize the deflection of the main lobe of the unit pattern, but also reduce the unit gain in the undesired area, thereby significantly reducing the sidelobe level of the array at a large angle; (2) The present invention only requires a single layer of medium, and utilizes the coupling feeding of a monopole and a bent dipole, and superimposes the radiation fields of the two to achieve unit pattern deflection and gain control. There is no need to design an additional feeding network for the monopole, making the unit structure compact and the feeding structure simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of the two-dimensional structure of a compact ultra-wide angle scanning antenna array with adjustable unit radiation pattern according to the present invention; Figure 2 It is a schematic diagram of the three-dimensional structure of a compact ultra-wide angle scanning antenna array with adjustable unit radiation pattern according to the present invention; Figure 3 The S11 results of the directional pattern adjustable unit in the left-biased mode, the middle mode, and the right-biased mode; Figure 4 The directional pattern results of the directional pattern adjustable unit in the left-biased mode, the middle mode and the right-biased mode; Figure 5 This is the result of 1×16 dimensional array wide angle beam scanning; Figure 6 The comparison results of the directional patterns of the array of the present invention and the traditional dipole array at a scanning angle of -70° are shown; Figure 7 The comparison results of the directional patterns of the array of the present invention and the traditional dipole array at a scanning angle of +70° are shown.

[0008] Reference numerals: 1. dielectric substrate, 2. feed line, 3. bent dipole, 4. left monopole, 5. right monopole, 6-1. first DC bias line, 6-2. second DC bias line, 7. first diode, 8. second diode, 9-1. first metallized through hole, 9-2. fifth metallized through hole, 10. second metallized through hole, 11. third metallized through hole, 12-1. fourth metallized through hole, 12-2. sixth metallized through hole, 13. metal ground, 3-1. first dipole arm, 3-2. second dipole arm, 3-3. metal microstrip line. DETAILED DESCRIPTION

[0009] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0010] like Figure 1 and 2 As shown, the compact ultra-wide angle scanning antenna array based on adjustable unit pattern of the present invention comprises: a dielectric substrate 1, a plurality of adjustable pattern units with the same structure, and the present invention is preferably set to 16 adjustable pattern units, each adjustable pattern unit comprises a feed line 2, a bent dipole 3, a left monopole 4, a right monopole 5, a first DC bias line 6-1, a second DC bias line 6-2, a first diode 7 loaded by the left monopole, a second diode 8 loaded by the right monopole, a first metallized through hole 9-1, a fifth metallized through hole 9-2, a second metallized through hole 10, a third metallized through hole 11, a fourth metallized through hole 12-1, a sixth metallized through hole 12-2 and a metal ground 13. Among them, The dielectric substrate 1 is selected from Rogers 4003 dielectric with a thickness of 0.813 mm; The feed line 2 is a feeding structure of the unit with adjustable directivity pattern, and is used to stimulate the unit to radiate; the feed line 2 is in the form of a microstrip transmission line, and is located on the upper layer of the dielectric substrate 1 .

[0011] The bent dipole 3 is used to generate a radiation pattern; the first dipole arm 3-1 and the second dipole arm 3-2 of the bent dipole 3 are connected to the metal ground 13, and are located in the lower layer of the dielectric substrate 1. The first dipole arm 3-1 and the second dipole arm 3-2 are in the form of a concave microstrip line, and one of the vertical sides of the concave is connected to the metal ground 13. Among them, the first dipole arm 3-1 has an L-shaped gap at one of the vertical sides of the concave, and the metal microstrip line 3-3 is L-shaped and embedded in the L-shaped gap. The size of the metal microstrip line 3-3 is smaller than the L-shaped gap. One end of the metal microstrip line 3-3 is connected to the feeder 2 through the third metallized through hole 11, and the other end is connected to the first dipole arm 3-1.

[0012] The left monopole 4 is used for coupling the radiation field of the bent dipole 3 to form a monopole radiation field, and superimposes the radiation field of the bent dipole 3 to generate a radiation field of a left-biased mode; The right monopole 5 is used to couple the radiation field of the bent dipole 3 to form a monopole radiation field, and superimpose the radiation field of the bent dipole 3 to generate a radiation field in a right-biased mode; The left monopole 4 and the right monopole 5 are located on the upper layer of the dielectric substrate, wherein the left monopole 4 and the right monopole 5 are projected onto the metal ground 13, and their respective projections overlap with the concave lateral sides of the first dipole arm 3-1 and the second dipole arm 3-2, and preferably, the overlapping intersection is the midpoint of the concave lateral side.

[0013] The first DC bias line 6-1, the second DC bias line 6-2, the first diode 7 loaded by the left monopole, and the second diode 8 loaded by the right monopole are used to control whether the left monopole 4 and the right monopole 5 form radiation; wherein the first diode 7 and the second diode 8 are respectively located at the lower ends of the left monopole 4 and the right monopole 5, and the ends of the left monopole 4 and the right monopole 5 are connected to the first DC bias line 6-1 and the second DC bias line 6-2, wherein the first DC bias line 6-1 and the second DC bias line 6-2 also include fan-shaped microstrip lines connected to their ends, which are used to achieve broadband isolation of the RF signal in the monopole.

[0014] The first metallized through hole 9-1 is used to weld the DuPont wire to control the conduction and disconnection of the first diode 7. A similar structure is also applied to the second diode 8 of the right monopole 5, that is, the fifth metallized through hole 9-2, which is used to weld the DuPont wire to control the conduction and disconnection of the second diode 8. That is, Figure 1 As shown, the structures of the left monopole 4 and the right monopole 5 on the front side of the dielectric substrate are symmetrically distributed.

[0015] The second metallized through hole 10 is used to connect the short "I"-shaped microstrip line on the front side of the bent dipole 3 and the first dipole arm 3-1 on the back side; wherein the second metallized through hole 10 includes two metal through holes, the L-shaped gap of the first dipole arm 3-1 divides the first dipole arm 3-1 into two parts, and the two second metallized through holes 10 connect the two parts to the short "I"-shaped microstrip line on the front side of the dielectric substrate.

[0016] A third metallized through hole 11, used to connect the feed line 2 and the metal microstrip line 3-3 on the back side; The fourth metallized through hole 12 - 1 is used to connect the left monopole 4 and the metal ground 13 ; the sixth metallized through hole 12 - 2 is used to connect the right monopole 5 and the metal ground 13 ; The metal 13 is used as a metal floor for the antenna.

[0017] Different phase excitations are fed to the array through each unit feed line to achieve beam scanning. Figure 4 The unit has three working modes, namely left-biased mode, middle mode and right-biased mode. The S parameters of the three modes are as follows Figure 3 As shown, S11 is less than -10dB in the frequency range of 8.5-9.5GHz. When the first diode 7 loaded on the left monopole 4 is turned on and the second diode 8 loaded on the right monopole 5 is turned off, the left monopole 4 radiates by coupling with the bent dipole 3. The radiation field of the left monopole 4 is superimposed on the radiation electric field of the bent dipole 3, causing the main lobe of the radiation pattern to deflect to the left; similarly, when the first diode 7 loaded on the left monopole 4 is turned off and the second diode 8 loaded on the right monopole 5 is turned on, the right monopole 5 radiates by coupling with the bent dipole 3. The radiation field of the right monopole 5 is superimposed on the radiation electric field of the bent dipole 3, causing the main lobe of the radiation pattern to deflect to the right; when the first diode 7 and the second diode 8 are turned off at the same time, only the bent dipole 3 radiates, and the pattern is not deflected at this time. As shown in FIG. Figure 4 As shown, at 9 GHz, the main lobes of the left-biased, middle-biased and right-biased mode radiation patterns point to -42°, 3° and 40° respectively, and the gains of the three modes are 5.1 dB, 3.7 dB and 4.9 dB respectively.

[0018] Based on the above-mentioned reconfigurable units, a 1×16 one-dimensional linear array is formed at equal intervals. The upper half scanning space is divided into three areas: -70°~-50°, -50°~+50°, and +50°~+70°.

[0019] like Figure 5 As shown, in the -70°~-50° scanning area, the first diode 7 loaded on the left monopole 4 of each directional pattern reconfigurable unit is turned on, and the second diode 8 loaded on the right monopole 5 is turned off. At this time, the unit pattern beam is tilted toward the left scanning area, and the gain of the undesired scanning area on the right will be significantly reduced. By changing the excitation phase of each directional pattern reconfigurable unit, the gain of the array in the -70°~-50° scanning area can be improved, and the sidelobe level of the array in the -30°~+70° area can be significantly reduced.

[0020] In the scanning area of ​​-50° to +50°, the first diode 7 and the second diode 8 loaded on the left monopole 4 and the right monopole 5 of each directional pattern reconfigurable unit are both disconnected. At this time, the directional pattern beam of the directional pattern reconfigurable unit points to the zenith direction.

[0021] In the +50°~+70° scanning area, the first diode 7 loaded on the left monopole 4 of each directional pattern reconfigurable unit is disconnected, and the second diode 8 loaded on the right monopole 5 is turned on. At this time, the directional pattern beam of the directional pattern reconfigurable unit is tilted toward the right scanning area, and the gain of the undesired scanning area on the left will be significantly reduced. By changing the excitation phase of each directional pattern reconfigurable unit, the gain of the array in the +50°~+70° scanning area can be improved, and the sidelobe level of the array in the -70°~+30° area can be significantly reduced.

[0022] As a preferred solution, the first diode 7 and the second diode 8 are of the MACOM-MA4AGP907 model, which has small reverse junction capacitance and low on-resistance characteristics, and is conducive to improving radiation performance.

[0023] As a preferred solution, the spacing between multiple directional pattern adjustable units is [0.48 , 0.5 ], in represents the free-space wavelength at 9 GHz.

[0024] In order to reduce the sidelobe level of the array at a large scanning angle, when it is necessary to scan to -70°~-50°, each unit is controlled to be in the left-bias mode, and the array can generate the following Figure 5 The sidelobe level of the -70°, -60° and -50° patterns is lower than -11dB; when scanning to -50°~+50° is required, each unit is controlled to be in the middle mode, and the array can produce Figure 5 The sidelobe level of the -40°, -30°, -20°, -10°, 0°, 10°, 20°, 30° and 40° directional patterns is lower than -11dB; when it is necessary to scan to +50°~+70°, each unit is controlled in the right-bias mode, and the array can produce the following Figure 5 The sidelobe level of the 50°, 60° and 70° patterns is lower than -11dB; like Figure 6 As shown in the figure, when the array of the present invention is scanned to -70°, the maximum sidelobe level is significantly reduced compared with the traditional dipole array, and the sidelobe level is also suppressed in the -30°~90° region. While achieving the sidelobe reduction, the array of the present invention also significantly improves the main lobe gain at -70°.

[0025] like Figure 7 As shown in the figure, when the array of the present invention is scanned to +70°, the maximum sidelobe level is significantly reduced compared with the traditional dipole array, and the sidelobe level is also suppressed in the -90°~+30° region. While achieving the sidelobe reduction, the array of the present invention also significantly improves the main lobe gain at +70°.

[0026] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern, characterized in that: It includes a dielectric substrate and a plurality of directional pattern adjustable units with the same structure, each directional pattern adjustable unit includes a feed line, a bent dipole, a left monopole, a right monopole, a first DC bias line, a second DC bias line, a first diode loaded by the left monopole, a second diode loaded by the right monopole, a first metallized through hole, a fifth metallized through hole, a second metallized through hole, a third metallized through hole, a fourth metallized through hole, a sixth metallized through hole and a metal ground, wherein: The left monopole and the right monopole are symmetrically distributed on the upper surface of the dielectric substrate, and the metal ground is located on the lower surface of the dielectric substrate; The first DC bias line is connected to the end of the left monopole and is used to control the on-off of the first diode, and the first DC bias line is connected to the metal ground through the first metallized through hole; the second DC bias line is connected to the end of the right monopole and is used to control the on-off of the second diode, and the second DC bias line is connected to the metal ground through the fifth metallized through hole; The first dipole arm and the second dipole arm of the bent dipole are directly connected to the metal ground, the metal microstrip line of the bent dipole is located on the upper surface of the dielectric substrate and is connected to the first dipole arm through the second metallized through hole, and the first dipole arm is connected to the feeder line on the upper surface of the dielectric substrate through the third metallized through hole; The left monopole and the right monopole are connected to the metal ground through a fourth metallized through hole and a sixth metallized through hole respectively.

2. A compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern according to claim 1, characterized in that: The first dipole arm and the second dipole arm are in the form of a concave microstrip line, one of the vertical sides of the concave shape is connected to the metal ground, wherein the first dipole arm has an L-shaped gap at one of the vertical sides of the concave shape, the metal microstrip line is embedded in the L-shaped gap, one end is connected to the feeder through a third metallized through hole, and the other end is connected to the first dipole arm.

3. The compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern according to claim 1, characterized in that: The left monopole is used to couple the radiation field of the bent dipole to form a monopole radiation field, and is superimposed with the radiation field of the bent dipole to generate a radiation field in a left-biased mode.

4. The compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern according to claim 1, characterized in that: The right monopole is used to couple the radiation field of the bent dipole to form a monopole radiation field, and is superimposed with the radiation field of the bent dipole to generate a radiation field in a right-biased mode.

5. The compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern according to claim 1, characterized in that: The left monopole and the right monopole are projected onto the metal ground, and their respective projections overlap with the concave lateral sides of the first dipole arm and the second dipole arm.

6. The compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern according to claim 1, characterized in that: The first DC bias line and the second DC bias line also include fan-shaped microstrip lines connected to their ends.

7. The compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern according to claim 1, characterized in that: The first metallized through hole is used to weld the DuPont wire to control the conduction and disconnection of the first diode, and the fifth metallized through hole is used to weld the DuPont wire to control the conduction and disconnection of the second diode.

8. The compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern according to claim 1, characterized in that: The metal microstrip line of the bent dipole is a short "I"-shaped microstrip line.

9. The compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern according to claim 1, characterized in that: The second metallized through hole 10 includes two metal through holes; the L-shaped gap of the first dipole arm divides the first dipole arm into two parts.

10. The compact ultra-wide angle scanning antenna array based on adjustable unit radiation pattern according to claim 9, characterized in that: The two second metallized through holes connect the two parts of the first dipole arm to the short "I"-shaped microstrip line on the front side of the dielectric substrate.

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