A microstrip antenna with wide bandwidth and wide beam

Abstract

A microstrip antenna with a wide bandwidth and wide beam belongs to the field of wireless communication and antenna technology. The microstrip antenna achieves wide-band characteristics by introducing a parasitic patch to excite the fusion of multiple resonant modes, and adjusts the current flow direction to maintain high-gain wide-beam characteristics within a wide-band range by combining a bending unit and an end structure to form a serpentine bending structure. The microstrip antenna of the present invention can simultaneously achieve wide beam and high gain characteristics, and the maximum gain of the antenna beam can reach 7.9dBi. Within the bandwidth, the beam width of the antenna with a gain of more than 3dBi can reach nearly 120°. The present invention utilizes a multi-unit structure, a tail design, and a parasitic unit to fuse multiple modes to expand the bandwidth of the antenna, which can cover an impedance bandwidth of about 28% of 4.99GHz-6.62GHz, and can be extended to any frequency band. The present invention can solve the problem that broadband, high gain, and wide beam characteristics cannot be integrated in the same antenna in the past, and achieve stable high gain and wide beam coverage within a wide bandwidth.

Description

Technical Field

[0001] The invention belongs to the technical field of wireless communication and antennas, and relates to a microstrip antenna with a wide frequency band and a wide beam. Background Art

[0002] The rapid development of wireless communication systems has put forward higher requirements on antenna characteristics to meet higher data transmission rates and more stable communication connections. In particular, how to use a set of antennas to meet the needs of complex mobile communication scenarios has become a hot topic in current antenna research. Chinese invention patent CN202210985066.5 (CN117638488A) discloses a microstrip antenna that couples with a patch radiator through an impedance matching structure to increase the bandwidth of the microstrip antenna. Its operating frequency band reaches 61.63~63.1GHz, but its 60GHz directional pattern peak gain is about 6.8dBi, the gain decays rapidly, and the beam width greater than 3dbi is small. Chinese invention patent CN202411017061.9 (CN118748320A) discloses a wideband tuned microstrip antenna, and proposes a wideband tuned edge radiating microstrip antenna that can take into account the characteristics of stable directional pattern, fast tuning, small size and low profile, but it has the problems of too narrow working bandwidth and too small beam width. In complex communication scenarios, antennas need to cover multiple frequency bands at the same time with one aperture, which not only reduces the space occupied by the antenna, but also meets the application requirements of multi-band and multi-scenario. In addition, broadband or multi-band antennas need to have both wide beam coverage and high gain characteristics to improve signal coverage and signal reception quality. However, there is a mutual constraint relationship between antenna beam width and gain, so realizing antennas with wide beams and high gain is still a very big challenge.

[0003] Microstrip antennas have attracted widespread attention due to their simple structure, flexible design, and low manufacturing cost. Although traditional microstrip antennas can achieve high gain within a certain radiation range, they have narrow bandwidth and low gain at low elevation angles, making it difficult to meet the requirements of indoor communication applications. Existing microstrip antennas improve the antenna's beam coverage by changing the floor structure, loading a back cavity structure or loading a vertical radiation structure, or mixing other antennas. However, these designs usually have insufficient bandwidth, and the antenna size is usually large or the antenna gain is low. Therefore, research on miniaturized microstrip antennas that have broadband, high gain, and wide beam characteristics will have strong market competitiveness. Summary of the invention

[0004] In view of the shortcomings and deficiencies in the prior art, the present invention proposes a microstrip antenna with a wide bandwidth and wide beam. By designing six bending units and the end into a bending structure, the currents of each unit are superimposed, thereby compressing the H-plane beam and widening the beam on the E-plane. Parasitic patches are introduced between the bending units, and the main radiating unit generates a coupling current on the surface of the parasitic unit through electromagnetic coupling, thereby exciting a new resonance point. By adjusting the size of the parasitic unit or the distance between the parasitic unit and the main radiating unit, the new resonance point is merged with the original resonance point, thereby improving the bandwidth of the antenna. The antenna adopts a CPW feeding method. The impedance bandwidth of the microstrip antenna can cover 4.99GHz-6.62GHz, maintain a stable high-gain radiation characteristic within the working frequency band, and the average gain can reach 7.7dBi. The range of the antenna beam gain greater than 3dbi within the bandwidth can reach nearly 120°. The microstrip antenna with a wide bandwidth, high gain and wide beam scanning characteristics proposed by the present invention has broad market prospects and application range.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A wide-bandwidth microstrip antenna, wherein the microstrip antenna achieves wide-bandwidth characteristics by introducing a parasitic unit (parasitic patch) to stimulate the fusion of multiple resonant modes, and adjusts the current flow direction to maintain high-gain wide-beam characteristics within a wide-band range by combining a bending unit and an end design to form a bending structure. The microstrip antenna comprises: a metal patch 1, a dielectric substrate 2, a metal floor 3, and a metal microstrip line 4. The metal patch 1 and the metal floor 3 are respectively located on the front and back sides of the dielectric substrate 2, and the metal floor 3 introduces a metal microstrip line 4. Specifically:

[0007] The metal patch 1 has multiple radiating elements, wherein the main radiator is a serpentine bending structure, including 6 bending units and their end structures, and coupled with multiple parasitic patches, which together constitute the top antenna radiation structure. The 6 bending units and the end structure are placed on the dielectric substrate 2 in an integrated design, and the integrated design can solve the manufacturing and assembly problems during actual processing. There are three parasitic patches, which are divided into regular patches and irregular patches. They are inserted into the unit gaps of the serpentine bending structure close to the feeding point to generate coupling currents, thereby introducing new resonance points to expand the bandwidth. There are two end structures, which are arranged inward at the outermost ends of the 6 bending units. The bent microstrip structure formed by the 6 bending units and the end can excite currents in the same direction to compress the H plane and widen the E plane.

[0008] The front side of the dielectric substrate 2 is provided with a metal patch 1, and the back side thereof is provided with a metal floor 3. Meanwhile, a metal microstrip line 4 is embedded inside the metal floor 3 to form a feeding network, which is a microstrip antenna having broadband, high gain, and wide beam scanning characteristics.

[0009] Furthermore, the bending unit and the end of the metal patch 1 are interconnected to ensure that the length of each bending unit and the end is an integer multiple of λ / 2 (where λ represents the wavelength corresponding to the center frequency of the working bandwidth), so that only the current in the same direction is effective, thereby realizing a compact antenna design and achieving wide beam coverage characteristics.

[0010] Furthermore, in the metal patch 1, multiple parasitic patches are introduced into the unit gap of the serpentine bending structure, and attention is paid to the gap between the introduced parasitic patch and the bending unit, the gap ensures that the coupled parasitic patch can excite the current to generate a higher-order mode, so that the new resonance point merges with the original resonance point, thereby widening the antenna bandwidth. Furthermore, in the parasitic patch, there is one irregular patch and two regular patches, and the irregular patch is located between the regular patches.

[0011] Furthermore, the dielectric substrate 2 has a low dielectric constant, which is not greater than 10.

[0012] Furthermore, a coplanar waveguide (CPW) feeding network structure is formed between the metal microstrip line 4 and the metal floor 3, and metal vias 5 are provided at corresponding positions of the metal microstrip line 4 and the metal floor 3, passing through the dielectric substrate 2 and connecting the center of the bending unit of the metal patch 1 to form a target current and form an E-plane wide beam. Using CPW as a feeding network to excite the antenna can obtain smaller radiation loss.

[0013] Furthermore, the metal floor 3 needs to use an ideal conductor to reach the metal via 5 of the metal patch 1 through the dielectric substrate 2, specifically a conductive metal material, including conductive metals such as copper, aluminum, silver, or their alloys.

[0014] Furthermore, the current of the bent patch in the metal patch 1 is introduced to the center of the bent patch through the metal via 5 on the dielectric substrate 2, and a metal microstrip line is embedded in the metal floor to form a CPW feeding network. The CPW feeding connection metal via 5 adopts a rectangular structure design, but is not limited to a rectangular structure, and can be expanded into other shapes such as a circle and a square to achieve signal transmission. The CPW feeding method can also be: coaxial line feeding, probe feeding, etc.:

[0015] When the coaxial line feeding method is used, the inner core of the coaxial line can be connected to the center of the bent structure patch, and the outer skin of the coaxial line can be connected to the metal floor.

[0016] When the probe feeding method is used, the feeding network can be designed by adding a metal microstrip line for excitation, so that the current on the bent structure only retains the same direction current, so as to achieve the effect of high gain and wide beam.

[0017] Furthermore, the number of bent patches in the microstrip antenna metal patch 1 is not limited to 6 units, and can be increased or decreased according to specific dimensions, and the size of the units is not limited to the same size and form, and can be adjusted to units of different sizes to adjust the beam coverage range.

[0018] Furthermore, the design of the terminal structure in the microstrip antenna metal patch 1 is not limited to this shape, and can be adjusted according to actual requirements to achieve the target effect.

[0019] Furthermore, a parasitic unit is introduced into the unit gap of the serpentine bending structure, and a broadband design is achieved by exciting and merging multiple modes of the antenna. The parasitic unit is not limited to the same size, and can have different forms to excite higher-order modes to widen the frequency band. The position of the introduced parasitic unit is not limited to the exact center position, and the position can be adjusted up and down or left and right to also excite the higher-order modes of the antenna to achieve a broadband design.

[0020] The innovative points of the present invention are analyzed as follows:

[0021] (1) The present invention provides a microstrip antenna design that has broadband, high gain, and wide beam characteristics. (2) The bending structure is designed based on the half-wavelength current conversion principle to ensure that only the current in the same direction is effective, so that the E plane forms a high-gain wide beam. (3) By adding a coupled parasitic patch design to excite high-order modes, the multi-mode antenna bandwidth is expanded to achieve ultra-wideband design.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The microstrip antenna of the present invention can simultaneously achieve the characteristics of wide beam and high gain. The maximum gain of the antenna beam can reach 7.9 dBi. Within the bandwidth, the beam width of the antenna with a gain above 3 dBi can reach nearly 120°.

[0024] (2) The present invention utilizes a multi-unit structure, tail design and parasitic units to fuse multiple modes to expand the bandwidth of the antenna, which can cover an impedance bandwidth of about 28% from 4.99 GHz to 6.62 GHz; but it is not limited to this frequency band, and the present invention can be extended to any frequency band.

[0025] (3) The present invention can solve the problem that broadband, high gain and wide beam characteristics cannot be integrated into the same antenna in the past, and achieve stable high gain and wide beam coverage within a broadband range. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the broadband wideband beam microstrip antenna proposed by the present invention;

[0027] Figure 2 It is a cross-sectional schematic diagram of the overall structure of the broadband wideband beam microstrip antenna proposed by the present invention;

[0028] Figure 3 It is a schematic diagram of the front and back structures of the broadband wideband beam microstrip antenna proposed by the present invention; Figure 3 (a) is the front side, where L1=60mm, L2=30mm; Figure 3 (b) in the figure is the reverse side;

[0029] Figure 4 is a reflection coefficient curve diagram of the present invention simulation;

[0030] Figure 5 is the gain pattern simulated by the present invention;

[0031] Figure 6 is a directional graph; Figure 6 (a) is the xoz radiation pattern at 5.25GHz. Figure 6 (b) in the figure is the xoz plane radiation pattern at 5.8GHz.

[0032] In the figure: 1 metal patch; 2 dielectric substrate; 3 metal floor; 4 metal microstrip line; 5 metal via; 6 groove between the metal floor and the CPW microstrip line. DETAILED DESCRIPTION

[0033] The specific implementation scheme of the present invention is described in detail below in conjunction with the accompanying drawings and technical solutions of the specification.

[0034] refer to Figure 1 The overall structure diagram of the broadband wide-band beam microstrip antenna is shown in Figure 1. The broadband wide-band beam microstrip antenna comprises, from top to bottom, a metal patch 1, a dielectric substrate 2, and a metal floor 3. In addition, a groove is added at the bottom of the metal floor 3 to place a CPW microstrip line to form a feeding network.

[0035] refer to Figure 2Structural cross-sectional view of broadband wideband beam microstrip antenna. Metal patch 1 is made of conductor material (copper), and consists of a bent patch and three parasitic units. The bent patch is formed by the joint end design of six bent units, and the length of each bent unit and the end is 0.5λ0 (where λ0 represents the wavelength corresponding to the center frequency of the working bandwidth 5GHz), and the line width is 2.53mm. The parasitic unit above the bent patch is composed of a pair of symmetrical rectangular patches (rectangular patches are 2mm long and 1.8mm wide) distributed on both sides from top to bottom, and the middle part is composed of a rectangular patch (11.75mm long and 2.1mm wide), a rectangular patch (2mm long and 6.9mm wide) and a rectangular patch (1.1mm long and 2.4mm wide); the parasitic unit below the bent patch is a pair of symmetrical rectangular patches (3.7mm long and 10.4mm wide).

[0036] The bending unit adopts a Z-shaped structure with two horizontal patches and one vertical patch. The terminal design also adopts two horizontal patches and one vertical patch, but forms an N-shaped structure. The bending unit and the terminal are connected end to end to form an integrated structure, so that the current on the bending patch is regular, that is, there is only current in the vertical direction, and the current in the horizontal direction is completely offset, thereby forming a high-gain wide beam. The parasitic patch is divided into a regular part and an irregular part, as shown in the reference Figure 2 As shown, the irregular parasitic patch is placed above the bent patch, close to the feeding point; the regular patch is placed below the bent patch, in a centrally symmetrical manner.

[0037] The rectangular low dielectric constant dielectric substrate 2 is made of FR4 material ( , ), the dielectric substrate is 2mm thick, 60mm long and 40mm wide. The size of the metal floor 3 is consistent with the dielectric substrate, 60mm long and 40mm wide, with a groove at the bottom to place the metal microstrip line. The metal microstrip line is divided into two rectangles. The upper rectangle is 4mm long and 2.9mm wide, with a metal via 5 with a radius of 0.5mm and a height of 2mm placed in its center; the lower rectangle is 3.72mm long and 12.75mm wide. At the same time, the width of the gap between the metal microstrip line 4 and the metal floor 3 is ensured to be 0.435mm at each location.

[0038] refer to Figure 3 (a) is a top view of a dielectric substrate 2, on which a metal patch is placed, which is composed of a bent patch and a parasitic unit. A metal via 5 extending from the bottom metal microstrip line is placed at the center of the bent patch, so that current is excited to the patch radiator to achieve a wide beam and high gain radiation characteristic.

[0039] refer to Figure 3(b) is a bottom view of the dielectric substrate 2. Copper is clad on the dielectric substrate 2 as a metal floor 3, and a groove is formed at the bottom of the metal floor 3 and a metal microstrip line 4 is placed at the bottom to form a CPW feeding network.

[0040] refer to Figure 4 The reflection coefficient diagram of the simulated broadband wide-beam microstrip antenna is given by Figure 4 It can be seen that the impedance bandwidth of the antenna is 4.99 GHz-6.62 GHz.

[0041] refer to Figure 5 is the gain diagram of the broadband wide-beam microstrip antenna, given by Figure 5 It can be seen that the maximum gain that the antenna can achieve within the working bandwidth is 7.91dBi, and the gain within the impedance bandwidth is greater than 4.23dBi.

[0042] refer to Figure 6 (a) and Figure 6 (b) in the figure shows the normalized radiation pattern of the E-plane of the broadband wide-beam microstrip antenna at 5.25 GHz and 5.8 GHz respectively. Figure 6 (a) and Figure 6 As can be seen from (b) in the figure, the beam width of the E-plane radiation pattern of the antenna at both frequencies can reach about 120°.

[0043] The above-described embodiments merely express the implementation methods of the present invention, but they should not be understood as limiting the scope of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A microstrip antenna with a wide bandwidth and wide beam, characterized in that: The microstrip antenna achieves broadband characteristics by introducing a parasitic patch to excite the fusion of multiple resonant modes, and adjusts the current flow direction to maintain high-gain wide-beam characteristics within a broadband range by combining a bending unit and an end structure to form a serpentine bending structure; the microstrip antenna comprises: a metal patch (1), a dielectric substrate (2), a metal floor (3), and a metal microstrip line (4); the metal patch (1) and the metal floor (3) are respectively located on the front and back sides of the dielectric substrate (2); the metal floor (3) has a metal microstrip line (4) embedded inside to form a feeding network; The metal patch (1) has a plurality of radiating elements, wherein the main radiating element is a serpentine bending structure, including six bending units and their end structures, and is coupled with a plurality of parasitic patches to form a top-layer antenna radiating structure; the six bending units and the end structure are integrated and located on the dielectric substrate (2); The plurality of parasitic patches are inserted into the gap of the bending unit of the serpentine bending structure close to the feeding point to generate coupling current, and the excitation current generates a high-order mode, thereby introducing a new resonance point to expand the bandwidth; There are two terminal structures, which are arranged at the outermost ends of the six bending units and face inward; the bending microstrip structure formed by the six bending units and the terminal structures can excite current in the same direction to compress the H plane and widen the E plane; In the serpentine bending structure of the metal patch (1), the length of each bending unit and the end structure is an integer multiple of λ / 2, wherein λ represents the wavelength corresponding to the center frequency of the working bandwidth.

2. A broadband, wide-beam microstrip antenna according to claim 1, characterized in that: The dielectric substrate (2) adopts a low dielectric constant.

3. The broadband wideband microstrip antenna according to claim 1, characterized in that: Metal vias (5) are provided at corresponding positions of the metal microstrip line (4) and the metal floor (3); the current of the bent patch in the metal patch (1) is introduced to the center of the bent patch through the metal vias (5) on the dielectric substrate (2), and a coplanar waveguide CPW feeding network is formed between the metal floor (3) and the embedded metal microstrip line (4).

4. A broadband, wide-beam microstrip antenna according to claim 3, characterized in that: The metal via (5) is made of a conductive metal material; the metal via (5) includes a rectangular, circular, square or other shape to achieve signal transmission.

5. The broadband wideband microstrip antenna according to claim 3, characterized in that: The feeding method formed between the metal floor (3) and the embedded metal microstrip line (4) includes not only a coplanar waveguide CPW feeding network, but also coaxial line feeding and probe feeding: When the coaxial line feeding method is adopted, the inner core of the coaxial line is connected to the center of the bent structure patch, and the outer skin of the coaxial line is connected to the metal floor (3); When the probe feeding method is used, a feeding network is designed by adding a metal microstrip line for excitation, so that the current on the bent structure only retains the same direction current, achieving a high gain wide beam effect.

6. The broadband wideband microstrip antenna according to claim 1, characterized in that: The number of bent patches in the microstrip antenna metal patch (1) is not limited to six units, and can be increased or decreased according to specific dimensions. The size of the units is not limited to the same size and form, and can be adjusted to units of different sizes to adjust the beam coverage range.

7. The broadband wideband microstrip antenna according to claim 1, characterized in that: The design of the terminal structure in the microstrip antenna metal patch (1) is not limited to this shape, and can be adjusted according to actual requirements to achieve the target effect.

8. The broadband wideband microstrip antenna according to claim 1, characterized in that: A parasitic unit is introduced into the unit gap of the serpentine bending structure, and a broadband design is achieved by exciting and merging multiple modes of the antenna. The parasitic unit is not limited to the same size, and can have different forms to excite high-order modes to widen the frequency band. The position of the introduced parasitic unit is not limited to the exact center, and the position can be adjusted up and down or left and right to also excite high-order modes of the antenna to achieve a broadband design.

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