An ultra-wideband tightly coupled antenna array for special shapes

Abstract

The present invention discloses an ultra-wideband tightly coupled antenna array for use in special shapes, wherein the antenna structure comprises: a dielectric substrate, a metal floor and an array unit. The dielectric substrate has a trapezoidal plus square structure, and the antenna radiating unit is placed on the lower surface of the trapezoidal substrate. Each antenna array is composed of 16 array units, and a single array unit comprises two dipoles and an exponentially gradient balun. Adjacent dipoles are connected by an interdigitated structure, and the dipole arms on the left and right sides are appropriately extended to obtain ultra-wideband performance. The feed balun used in this antenna adopts an exponentially gradient structure, which has strong impedance matching capability and a relatively simple structure. The substrate structure of this antenna is relatively special, and the overall structure is a trapezoidal plus square structure, which is suitable for some scenes with relatively special spaces. This tightly coupled antenna array is made of PCB printing, and has the advantages of simple structure, space saving and low cost, and has good application prospects in scenes with certain special shapes.

Description

Technical Field

[0001] The present invention belongs to the field of mobile communication technology and relates to the design of antennas used in special scenarios, and in particular to an ultra-wideband tightly coupled antenna array used in special shapes. Background Art

[0002] In recent years, with the continuous development of wireless communication technology, the application scenarios of wireless communication systems have become more and more numerous. As part of the wireless communication system, the antenna, as the terminal component for transmission and reception, often affects the performance of the entire system.

[0003] With the continuous advancement of wireless communication technology, wireless communication systems are being added to an increasing number of scenarios. However, as application scenarios continue to evolve, integrating communication equipment into these uniquely shaped environments is a key research topic. Some systems require signals to be transmitted and received across a variety of frequency bands. Traditionally, multiple antennas have been deployed to accommodate these signals, increasing the number of devices required and creating interference between antennas. Ultra-wideband antennas offer a wide operating bandwidth, covering multiple frequency bands. Therefore, enabling a single antenna to operate across multiple required frequency bands and designing an ultra-wideband antenna that meets the specific requirements of the system has become a pressing challenge.

[0004] Tightly coupled antennas are ultra-wideband antennas characterized by ultra-wideband, small size, and low profile. They originate from Professor Wheeler's continuous current sheet arrays. When the arrays are closely arranged, a continuous current forms on the array surface. This dynamic balance of coupling capacitance between dipoles and inductance between the dipoles and the reflector achieves ultra-wideband matching across the entire frequency band. Tightly coupled antennas are also phased array antennas, and by introducing phase differences between each port, the antenna can radiate in different directions. Therefore, applying tight coupling technology to wireless communication systems has important practical engineering significance. Summary of the Invention

[0005] The present invention aims to solve the problems existing in the above-mentioned prior art and provides an ultra-wideband tightly coupled antenna array for use in special shapes, which has the advantages of ultra-wideband, good impedance matching, simple structure, and is easy to process and produce.

[0006] The technical solutions adopted by the present invention are as follows: an ultra-wideband tightly coupled antenna array for special shapes, composed of a number of array units arranged in a periodic manner, the array unit including a dielectric substrate, the dielectric substrate being a three-dimensional body with an upper trapezoid and a lower square, the lower surface of the top and the inner surfaces of the left and right sides of the dielectric substrate being printed with radiation units, the outer surfaces of the left and right sides of the dielectric substrate being printed with left and right metal patches respectively, a metal floor being provided below the dielectric substrate, a bottom dielectric substrate being closely attached below the metal floor, a microstrip power divider being printed on the bottom surface of the bottom dielectric substrate, an exponentially tapered balun being provided between the bottom dielectric substrate and the dielectric substrate for feeding, an intermediate dielectric base being provided in the middle vertical area between the metal floor and the top of the dielectric substrate The intermediate dielectric substrate is located in the middle of the entire antenna array, and a resistor is printed on the upper surface of the intermediate dielectric substrate. The radiating element is composed of a metal strip located on the lower surface of the top of the dielectric substrate and metal strips on the inner surfaces of the left and right sides. The left and right sides of the metal strip are respectively a left dipole and a right dipole. The left and right dipoles are connected by an interdigital structure and fed by an exponentially tapered balun. The arm of the left dipole is closely attached to the left inner surface of the dielectric substrate and is bent 77.3 degrees along the negative direction of the Z axis to extend to become the left metal strip. The arm of the right dipole is closely attached to the right inner surface of the dielectric substrate and is bent 90 degrees along the negative direction of the Z axis to extend to become the right metal strip. The left and right metal strips have different downward extension lengths.

[0007] Furthermore, the vertical direction perpendicular to the top surface of the dielectric substrate is the Z axis, the wide side direction of the top surface of the dielectric substrate is the X axis, the long side direction of the top surface of the dielectric substrate is the Y axis, the thickness of the dielectric substrate is 1.016 mm, the length of the top surface of the dielectric substrate is 70.504 mm, the length of the bottom surface of the dielectric substrate is 77.504 mm, the width of the top surface of the dielectric substrate is equal to the width of the bottom surface and is 67.4 mm, the overall height is 85.1 mm, the left side is bent downward by 77.3 degrees along the negative direction of the Z axis, the height of the bent portion is 31.084 mm, and then it is bent vertically downward by 90 degrees along the negative direction of the Z axis. The right side is bent vertically downward by 90 degrees along the negative direction of the Z axis.

[0008] Furthermore, the bottom dielectric substrate has the same physical dimensions as the metal floor, with a thickness of 1.016 mm, a length of 78.52 mm, and a width of 67.4 mm. The middle dielectric substrate has a thickness of 1.016 mm, a length of 75.472 mm, a width of 42.4 mm, and a height of 50 mm from the metal floor.

[0009] Furthermore, the dielectric substrate and the bottom dielectric substrate are made of Taconic TLY, with a dielectric constant of 2.2; the middle dielectric substrate is made of FR-4, with a dielectric constant of 4.4.

[0010] Furthermore, the left metal patch and the right metal patch are tightly attached to the left and right outer surfaces of the dielectric substrate. The left metal patch consists of two parts, the first part is the left vertical patch layer, and the second part is the bent patch layer. The right metal patch is the right vertical patch layer.

[0011] Furthermore, the height of the left vertical patch layer of the left metal patch is 53 mm, the length of the bent patch layer is 31.86 mm, the height of the right metal patch is 78 mm, and the widths of the left metal patch and the right metal patch are both 67.4 mm.

[0012] Furthermore, the length of the short side of the feeding part in the exponential gradient balun is 0.31 mm, the length of the long side of the feeding part is 0.92 mm, the length of the short side of the grounding part is 0.81 mm, the length of the long side of the grounding part is 6.9 mm, and the height of the exponential gradient balun is 87.132 mm.

[0013] Furthermore, the resistor sheet adopts a ring structure, with an outer ring width of 42.4 mm, an outer ring length of 75.472 mm, an inner ring distance of 26.516 mm from the left side of the outer ring, an inner ring width of 9 mm, and an inner ring length of 33.4 mm.

[0014] Furthermore, the metal floor is located between the dielectric substrate and the bottom dielectric substrate, and the metal floor is a whole piece of PEC material.

[0015] The present invention has the following beneficial effects:

[0016] (1) In the present invention, the left dipole and the right dipole are connected by an interdigital structure and extended downward to form an overlapping structure with the left metal patch and the right metal patch. These two structures can introduce strong coupling capacitance at low frequencies, which is beneficial to impedance matching at low frequencies and increases bandwidth.

[0017] (2) In the present invention, due to the special shape, simple structure and ultra-wideband characteristics of the antenna, the antenna can be applied to some relatively special shape scenarios.

[0018] (3) Compared with some other antennas with special shapes, the left metal patch and the right metal patch of the present invention act as reflectors, so that the radiation energy of the antenna is more concentrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the unit structure of an embodiment of the present invention.

[0020] Figure 2 Schematic diagram of a radiation unit according to an embodiment of the present invention.

[0021] Figure 3 Schematic diagram of the dimensions of the exponential gradient balun according to an embodiment of the present invention.

[0022] Figure 4 Schematic diagram of the top view and dimensions of the dielectric substrate and resistor sheet according to an embodiment of the present invention.

[0023] Figure 5 Schematic diagram of the left and right outer metal patches of an embodiment of the present invention.

[0024] Figure 6 This is a voltage standing wave ratio diagram of the antenna unit of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] The present invention is applied to ultra-wideband tightly coupled antenna arrays in special shapes. Each antenna array consists of 16 array units arranged in a periodic manner. Each antenna array has a periodic structure and is arranged in one dimension. For ease of understanding, only one unit is drawn in the figure. In actual use, the unit needs to be extended forward and backward.

[0027] The array unit comprises a dielectric substrate 1, which is a three-dimensional structure with a trapezoidal top and a square bottom. Radiating elements 2 are printed on the top lower surface and the left and right inner surfaces of the dielectric substrate 1. Left and right metal patches 3 and 10 are printed on the left and right outer surfaces of the dielectric substrate 1, respectively. A metal floor 4 is located beneath the dielectric substrate 1, and a bottom dielectric substrate 5 is closely attached to the metal floor 4. A microstrip power divider 7 is printed on the bottom surface of the bottom dielectric substrate 5. An exponentially tapered balun 6 provides power feed between the bottom dielectric substrate 5 and the dielectric substrate 1. An intermediate dielectric substrate 9 is located in the center of the entire antenna array, and a resistor 8 is printed on its top surface.

[0028] The dielectric substrate 1 has a structure of an upper trapezoid and a lower square. The special shape enables the antenna to be used in some occasions with special shapes.

[0029] The dielectric substrate 1 has a thickness of 1.016 mm, a short side length of 70.504 mm, a long side length of 77.504 mm, a width of 67.4 mm, and an overall height of 85.1 mm. The left side bends downward at 77.3 degrees along the negative Z-axis, with a height of 31.084 mm. It then bends vertically downward at 90 degrees along the negative Z-axis. The right side also bends vertically downward at 90 degrees along the negative Z-axis. The bottom dielectric substrate 5 and the metal floor 4 have the same physical dimensions: a thickness of 1.016 mm, a length of 78.52 mm, and a width of 67.4 mm. The middle dielectric substrate 9 has a thickness of 1.016 mm, a length of 75.472 mm, a width of 42.4 mm, and a height of 50 mm from the metal floor 4. Both the dielectric substrate 1 and the bottom dielectric substrate 5 are made of Taconic TLY, with a dielectric constant of 2.2. The middle dielectric substrate 9 is made of FR-4, with a dielectric constant of 4.4. The intermediate dielectric substrate 9 is located in the middle vertical area between the metal floor 4 and the top of the dielectric substrate (1), and the specific position is as follows: Figure 1 shown.

[0030] The radiating element 2 consists of a metal strip 21 located on the top lower surface of the dielectric substrate 1, and metal strips 22 on the left and right inner surfaces. The left and right sides of the metal strip 21 are connected by a left dipole 211 and a right dipole 213, respectively. The left and right dipoles 211 and 213 are connected by an interdigital structure 212 and fed by an exponentially tapered balun 6. The arm of the left dipole 211, attached to the left inner surface of the dielectric substrate 1, bends 77.3 degrees along the negative Z-axis to form the left metal strip 221. The arm of the right dipole 213, attached to the right inner surface of the dielectric substrate 1, bends 90 degrees along the negative Z-axis to form the right metal strip 222. As they extend downward, they also extend to the left and right sides. Due to the asymmetry between the left and right sides, the downward extension lengths of the left and right metal strips 221 and 222 are different.

[0031] The interdigital structure 212 generates coupling capacitance, partially offsetting the ground inductance. The left and right dipoles 211 and 213 conform to the upper trapezoidal shape of the dielectric substrate 1, extending along the negative Z-axis and extending to the left and right to form two extended arms, the left metal strip 221 and the right metal strip 222, further enhancing ultra-wideband performance. Due to the asymmetric structure, the downward extension length is also inconsistent, effectively preventing deviation in the antenna pattern.

[0032] The metal strip 21 (bottom surface of the top) and the interdigitated structure 212 of the radiation unit 2 are arranged symmetrically about the central horizontal axis, while the lengths of the left metal strip 221 and the right metal strip 222 (left and right inner surfaces) extending downward are inconsistent to compensate for the phase difference caused by the asymmetric bending of the dielectric substrate 1. To simplify the diagram, only half of the structure is marked. The length of the first left vertical side 2211 is 30.4mm, the length of the first left oblique side 2212 is 32.76mm, the length of the second left vertical side 2111 is 15.2mm, and the midpoints of the first left vertical side 2211 and the second left vertical side 2111 are on the same horizontal line. The length of the first left horizontal side 2112 is 13.484mm, the length of the second left oblique side 2113 is 9.5mm, the length of the third vertical side 2114 is 1.016mm, and the distance between the two arms of the left dipole 211 and the right dipole 213 is 1.016m. m, the length of the second left horizontal edge 2115 is 6 mm, the length of the interdigital structure 212 is 18.23 mm, the length of the finger length 2122 is 3.64 mm, the distance 2123 between the upper and lower fingers is 1.23 mm, and the distance 2124 between the left and right fingers is 0.064 mm. The left and right dipole arms of the interdigital structure 212 are symmetrical with each other and have the same size, so they are no longer marked. The length of the first right horizontal edge 2131 is 9.524 mm, and the length of the first right oblique edge 2221 is 46.7 mm. The unmarked structures have the same size as the previous similar structures.

[0033] The left and right metal patches 3 and 10 are attached to the left and right outer surfaces of the dielectric substrate 1. The left metal patch 3 is located on the left and consists of two parts: a left vertical patch layer 31 and a slightly curved bent patch layer 32. The right metal patch 10 is a vertical right vertical patch layer. The left vertical patch layer 31 of the left metal patch 3 is 53 mm high, and the bent patch layer 32 is 31.86 mm long. They adhere closely to the outer hypotenuse of the dielectric substrate 1. The right metal patch 10 is 78 mm high. Both the left and right metal patches 3 and 10 are 67.4 mm wide.

[0034] The left and right metal patches 3 and 10, combined with the left and right metal strips 221 and 222, respectively, form a flat plate capacitor, offsetting the ground inductance. At the same time, the left and right metal patches 3 and 10 are raised, wrapping around the left and right metal strips 221 and 222, acting as reflective plates. This concentrates the antenna's energy and prevents significant deviations in the antenna pattern due to the asymmetric structure.

[0035] The exponentially tapered balun 6 is designed to match the impedance from the microstrip power divider 7 to the left dipole 211 and the right dipole 213. It is designed to match a 100Ω input impedance. The short side 621 of the feed section is 0.31mm long, the long side 622 of the feed section is 0.92mm long, the short side 611 of the ground section is 0.81mm long, and the long side 613 of the ground section is 6.9mm long. The entire balun is exponentially tapered, with a height 612 of 87.132mm.

[0036] In order to avoid contact between the intermediate dielectric substrate 9 and the resistor sheet 8 and the exponential gradient balun 6, a ring structure is adopted. The outer ring width 81 is 42.4 mm, the outer ring length 82 is 75.472 mm, the distance 85 between the inner ring and the left side of the outer ring is 26.516 mm, the inner ring width 83 is 9 mm, and the inner ring length 84 is 33.4 mm.

[0037] The radiating element of each antenna array consists of a left dipole 211 and a right dipole 213. The two dipoles are connected to the microstrip power divider 7 on the bottom surface of the bottom dielectric substrate 5 through the same index gradient balun 6, and are finally fed through the feed head.

[0038] The intermediate dielectric substrate 9 is located in the middle of the entire antenna array. A resistor sheet 8 is printed on the upper surface of the intermediate dielectric substrate 9 to absorb radiation waves.

[0039] The metal floor 4 is located between the dielectric substrate 1 and the bottom dielectric substrate 5 and serves as the grounding portion of the entire antenna. The metal floor 4 is made of a whole piece of PEC material.

[0040] Figure 5 is the voltage standing wave ratio (VSWR) of the ultra-wideband tightly coupled antenna array, which reflects the overall impedance matching of the antenna. Within the 0.3 GHz to 3.34 GHz frequency range, the VSWR is less than 3, indicating excellent matching and demonstrating that this embodiment achieves ultra-wideband performance.

[0041] The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be regarded as the scope of protection of the present invention.

Claims

1. An ultra-wideband tightly coupled antenna array for use in special shapes, comprising a plurality of periodically arranged array elements, characterized in that: The array unit comprises a dielectric substrate (1), the dielectric substrate (1) is a three-dimensional structure with an upper trapezoid and a lower square, a radiation unit (2) is printed on the lower surface of the top and the inner surfaces on the left and right sides of the dielectric substrate (1), a left metal patch (3) and a right metal patch (10) are printed on the outer surfaces on the left and right sides of the dielectric substrate (1), a metal floor (4) is provided below the dielectric substrate (1), a bottom dielectric substrate (5) is closely attached below the metal floor (4), a microstrip power divider (7) is printed on the bottom surface of the bottom dielectric substrate (5), an exponential gradient balun (6) is provided between the bottom dielectric substrate (5) and the dielectric substrate (1) for feeding, an intermediate dielectric substrate (9) is provided in the middle vertical area between the metal floor (4) and the top of the dielectric substrate (1), the intermediate dielectric substrate (9) is located in the middle of the entire antenna array, and the upper surface of the intermediate dielectric substrate (9) is printed with a microstrip power divider (7). A resistor sheet (8) is brushed, and the radiation unit (2) is composed of a metal strip (21) located on the lower surface of the top of the dielectric substrate (1) and metal strips (22) on the inner surfaces of the left and right sides. The left and right sides of the metal strip (21) are respectively a left dipole (211) and a right dipole (213). The left dipole (211) and the right dipole (213) are connected by an interdigital structure (212) and fed by an exponential gradient balun (6). The arm of the left dipole (211) is closely attached to the inner surface of the left side of the dielectric substrate (1) and is bent 77.3 degrees along the negative direction of the Z axis to extend to become a left metal strip (221). The arm of the right dipole (213) is closely attached to the inner surface of the right side of the dielectric substrate (1) and is bent 90 degrees along the negative direction of the Z axis to extend to become a right metal strip (222). The lengths of the left metal strip (221) and the right metal strip (222) extending downward are inconsistent.

2. The ultra-wideband tightly coupled antenna array for special shapes according to claim 1, wherein: The vertical direction perpendicular to the top surface of the dielectric substrate (1) is the Z axis, the wide side direction of the top surface of the dielectric substrate (1) is the X axis, the long side direction of the top surface of the dielectric substrate (1) is the Y axis, the thickness of the dielectric substrate (1) is 1.016 mm, the length of the top surface of the dielectric substrate (1) is 70.504 mm, the length of the bottom surface of the dielectric substrate (1) is 77.504 mm, the width of the top surface of the dielectric substrate (1) is equal to the width of the bottom surface and is 67.4 mm, the overall height is 85.1 mm, the left side is bent 77.3 degrees downward along the negative direction of the Z axis, the height of the bent portion is 31.084 mm, and then it is bent 90 degrees vertically downward along the negative direction of the Z axis, and the right side is bent 90 degrees vertically downward along the negative direction of the Z axis.

3. The ultra-wideband tightly coupled antenna array for special shapes according to claim 2, wherein: The bottom dielectric substrate (5) has the same physical dimensions as the metal floor (4), with a thickness of 1.016 mm, a length of 78.52 mm, and a width of 67.4 mm. The middle dielectric substrate (9) has a thickness of 1.016 mm, a length of 75.472 mm, a width of 42.4 mm, and a height of 50 mm from the metal floor (4).

4. The ultra-wideband tightly coupled antenna array for special shapes according to claim 3, wherein: The dielectric substrate (1) and the bottom dielectric substrate (5) are made of Taconic TLY, with a dielectric constant of 2.2; the intermediate dielectric substrate (9) is made of FR-4, with a dielectric constant of 4.

4.

5. The ultra-wideband tightly coupled antenna array for special shapes according to claim 1, wherein: The left metal patch (3) and the right metal patch (10) are tightly attached to the left and right outer surfaces of the dielectric substrate (1); the left metal patch (3) is composed of two parts, the first part is a left vertical patch layer (31), and the second part is a bent patch layer (32); the right metal patch (10) is a right vertical patch layer.

6. The ultra-wideband tightly coupled antenna array for special shapes according to claim 5, wherein: The left vertical patch layer (31) of the left metal patch (3) has a height of 53 mm, the length of the bent patch layer (32) is 31.86 mm, the height of the right metal patch (10) is 78 mm, and the widths of the left metal patch (3) and the right metal patch (10) are both 67.4 mm.

7. The ultra-wideband tightly coupled antenna array for special shapes according to claim 1, wherein: The length of the short side (621) of the feeding part in the exponential gradient balun (6) is 0.31 mm, the length of the long side (622) of the feeding part is 0.92 mm, the length of the short side (611) of the grounding part is 0.81 mm, the length of the long side (613) of the grounding part is 6.9 mm, and the height (612) of the exponential gradient balun (6) is 87.132 mm.

8. The ultra-wideband tightly coupled antenna array for special shapes according to claim 1, wherein: The resistor sheet (8) has a ring structure, an outer ring width (81) of 42.4 mm, an outer ring length (82) of 75.472 mm, a distance (85) between the inner ring and the left side of the outer ring of 26.516 mm, an inner ring width (83) of 9 mm, and an inner ring length (84) of 33.4 mm.

9. The ultra-wideband tightly coupled antenna array for special shapes according to claim 1, wherein: The metal floor (4) is located between the dielectric substrate (1) and the bottom dielectric substrate (5), and the metal floor (4) is a whole piece of PEC material.

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