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

Abstract

The present invention discloses a compact, ultra-wide-angle scanning antenna array based on adjustable unit patterns. Based on the principle of superposition of the dipole and monopole patterns contained in the antenna units, unit pattern deflection is achieved and unit gain at undesired angles is reduced. Unit pattern deflection improves the array's gain at large scanning angles, enabling wide-angle scanning. Due to the low unit gain at undesired angles, low-sidelobe scanning of the array is possible. The present invention features a compact unit structure and a simple feeding structure. While maintaining wide-angle scanning capabilities, it also significantly reduces the array's sidelobe levels at large scanning angles.

Description

Technical Field

[0001] The present 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] With the increasing demand for wide-area beam coverage in airborne radar, automotive collision avoidance radar, and mobile communications, ultra-wide-angle scanning antennas are attracting significant attention from both academia and industry. However, conventional phased array antennas struggle to achieve wide-angle scanning due to factors such as element patterns, inter-element coupling, and matching. Their scanning range is typically limited to ±60°, and their gain attenuates significantly with increasing scanning angle (a 3-4 dB gain reduction at ±60°). This results in limited radar detection range and narrow coverage areas for communication base stations.

[0003] Existing wide-angle scanning arrays with adjustable directivity patterns generally have complex structures, often using multiple layers of dielectrics. This results in high array cost and manufacturing complexity. Furthermore, research on improving gain at large scanning angles and suppressing array sidelobe levels at large scanning angles is relatively lacking. Therefore, how to simultaneously achieve gain enhancement and sidelobe suppression at large scanning angles using a single dielectric layer remains an urgent technical challenge. 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. Based on the adjustable unit pattern and unit pattern gain control technology, it achieves gain improvement and sidelobe suppression at large scanning angles.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A compact ultra-wide angle scanning antenna array based on adjustable unit pattern includes a dielectric substrate and a plurality of adjustable pattern units with the same structure. Each adjustable pattern 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.

[0007] 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;

[0008] 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. The first DC bias line is connected to the metal ground through a 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. The second DC bias line is connected to the metal ground through a fifth metallized through-hole.

[0009] 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 a second metallized through-hole. The first dipole arm is connected to the feeder line on the upper surface of the dielectric substrate through a third metallized through-hole.

[0010] 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.

[0011] The beneficial effects of the present invention are:

[0012] (1) The present invention proposes a reconfigurable unit pattern with controllable regional gain. While achieving the deflection of the main lobe of the unit pattern, it can also reduce the unit gain in the undesired area, thereby significantly reducing the sidelobe level of the array at large angles.

[0013] (2) The present invention only requires a single layer of dielectric material, and utilizes the coupling feeding of a monopole and a bent dipole, superimposing 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

[0014] Figure 1 Schematic diagram of the two-dimensional structure of a compact ultra-wide angle scanning antenna array with adjustable unit pattern according to the present invention;

[0015] Figure 2 Schematic diagram of the three-dimensional structure of a compact ultra-wide angle scanning antenna array with adjustable unit pattern according to the present invention;

[0016] Figure 3 The S11 results of the directional pattern adjustable unit in the left-bias mode, the middle mode, and the right-bias mode;

[0017] Figure 4 The directional pattern results of the directional pattern adjustable unit in the left mode, the middle mode and the right mode;

[0018] Figure 5 This is the result of 1×16 array wide-angle beam scanning;

[0019] 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;

[0020] 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.

[0021] Reference numerals:

[0022] 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

[0023] The present invention will be further described below with reference to the accompanying drawings and examples.

[0024] 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 of the same structure, preferably 16 adjustable pattern units of the present invention, each adjustable pattern unit comprising 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,

[0025] The dielectric substrate 1 is a Rogers 4003 dielectric with a thickness of 0.813 mm.

[0026] 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 .

[0027] A bent dipole 3 is configured to generate a radiation pattern. The bent dipole 3 has a first dipole arm 3-1 and a second dipole arm 3-2 connected to a metal ground 13. The bent dipole 3 is located on the lower layer of the dielectric substrate 1. The first and second dipole arms 3-1, 3-2 are in the form of concave microstrip lines, with one vertical side of the concave shape connected to the metal ground 13. The first dipole arm 3-1 has an L-shaped slot on one of the vertical sides of the concave shape. A metal microstrip line 3-3 is L-shaped and embedded in the L-shaped slot. The metal microstrip line 3-3 is smaller than the L-shaped slot. One end of the metal microstrip line 3-3 is connected to the feeder 2 via a third metalized through-hole 11, and the other end is connected to the first dipole arm 3-1.

[0028] The left monopole 4 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 left-biased mode radiation field;

[0029] 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;

[0030] 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 horizontal side portions of the first dipole arm 3-1 and the second dipole arm 3-2. Preferably, the overlapping intersection is the midpoint of the concave horizontal side portion.

[0031] The first DC bias line 6-1, the second DC bias line 6-2, the first diode 7 loaded on the left monopole, and the second diode 8 loaded on 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 a fan-shaped microstrip line connected to their ends, which is used to achieve broadband isolation of the RF signal in the monopole.

[0032] The first metallized through hole 9-1 is used to solder a 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 is used to solder a DuPont wire to control the conduction and disconnection of the second diode 8. Figure 1 As shown, the left monopole 4 and the right monopole 5 are arranged symmetrically on the front surface of the dielectric substrate.

[0033] The second metallized through-hole 10 is used to connect the short "I"-shaped microstrip line on the front of the bent dipole 3 and the first dipole arm 3-1 on the back; 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 these two parts to the short "I"-shaped microstrip line on the front of the dielectric substrate.

[0034] A third metallized through hole 11 is used to connect the feed line 2 and the metal microstrip line 3-3 on the back side;

[0035] 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 ;

[0036] The metal 13 is used as a metal floor for the antenna.

[0037] The array is fed with different phase excitations through each unit feed line to achieve beam scanning. Figure 4 The unit has three working modes, namely left bias mode, middle mode and right bias 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 Figure 4 As shown, at 9 GHz, the main lobes of the left-biased, center-biased and right-biased mode 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.

[0038] Based on the above-mentioned reconfigurable pattern elements, a 1×16 one-dimensional linear array is formed at equal intervals. The upper half of the scanning space is divided into three regions: -70° to -50°, -50° to +50°, and +50° to +70°.

[0039] like Figure 5As shown, in the -70° to -50° scanning range, the first diode 7 attached to the left monopole 4 of each reconfigurable pattern element is turned on, while the second diode 8 attached to the right monopole 5 is turned off. At this point, the element pattern beam tilts toward the left scanning range, significantly reducing the gain in the undesired right scanning range. By varying the excitation phase of each reconfigurable pattern element, the array gain in the -70° to -50° scanning range can be increased, while the sidelobe level in the -30° to +70° range can be significantly reduced.

[0040] 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 pattern reconfigurable unit are both disconnected. At this time, the pattern beam of the pattern reconfigurable unit points to the zenith direction.

[0041] In the +50° to +70° scanning range, the first diode 7 attached to the left monopole 4 of each reconfigurable pattern unit is disconnected, while the second diode 8 attached to the right monopole 5 is turned on. At this point, the pattern beam of the reconfigurable pattern unit tilts toward the right scanning range, significantly reducing the gain in the undesired left scanning range. By varying the excitation phase of each reconfigurable pattern unit, the array gain in the +50° to +70° scanning range can be increased, while the sidelobe level in the -70° to +30° range can be significantly reduced.

[0042] 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, which is beneficial to improving radiation performance.

[0043] 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.

[0044] 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 produce 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° patterns is lower than -11dB; when it is necessary to scan to +50°~+70°, each unit is controlled to be in the right-deflection mode, and the array can produce the following Figure 5 The sidelobe levels of the 50°, 60° and 70° patterns are lower than -11dB;

[0045] like Figure 6 As shown, the array of the present invention significantly reduces the maximum sidelobe level when scanning to -70° compared to a traditional dipole array, and also achieves sidelobe suppression in the -30° to 90° region. While achieving sidelobe reduction, the array of the present invention also significantly improves the mainlobe gain at -70°.

[0046] like Figure 7 As shown, the array of the present invention significantly reduces the maximum sidelobe level when scanning to +70° compared to a traditional dipole array, and also achieves sidelobe suppression in the -90° to +30° region. While achieving sidelobe reduction, the array of the present invention also significantly improves the mainlobe gain at +70°.

[0047] 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 are only specific embodiments of the present invention and are 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 with adjustable unit pattern, characterized in that: The invention comprises a dielectric substrate and a plurality of directional pattern adjustable units with the same structure, each directional pattern adjustable unit comprising 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. The first DC bias line is connected to the metal ground through a 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. The second DC bias line is connected to the metal ground through a 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 a second metallized through-hole. The first dipole arm is connected to the feeder line on the upper surface of the dielectric substrate through a 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. The compact ultra-wide angle scanning antenna array with adjustable unit 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 feed line 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 with adjustable unit 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 with adjustable unit 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 with adjustable unit 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 horizontal sides of the first dipole arm and the second dipole arm.

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

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

8. The compact ultra-wide angle scanning antenna array with adjustable unit 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 with adjustable unit pattern according to claim 1, characterized in that: The second metallized through hole (10) comprises 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 with adjustable unit 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 surface of the dielectric substrate.

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