Wide-beam stable-gain end-on-fire antenna

Abstract

The invention discloses a wide-beam and stable-gain end-on-fire antenna, and relates to the technical field of antennas. Comprising an upper additional coating and a lower antenna layer. The antenna layer comprises an SIW third-order ridge waveguide horn, a coaxial feed, a slow wave structure, an air via hole and an additional ground structure AGS which are printed on a dielectric substrate; wherein the outer conductor of the coaxial feed is electrically connected with the lower metal layer of the SIW third-order ridge waveguide horn, and the inner conductor of the coaxial feed is connected with the leftmost end of the first-order ridge of the third-order ridges in the SIW third-order ridge waveguide horn; the slow wave structure is arranged around the ridge tail end of the third-order ridge, an air through hole is formed in a dielectric extension part at the tail end of the SIW third-order ridge waveguide horn, and an additional ground structure AGS is loaded at the tail part of a dielectric substrate at the lower layer of the extension part. According to the invention, electromagnetic waves can be regulated and controlled, so that the antenna has stable gain and polarization characteristics while the miniaturization design of the antenna is realized, and meanwhile, the problem of upward deflection of a wave beam in a large metal environment is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to an end-fire antenna with a wide beam and stable gain. Background Art

[0002] With the rapid development of wireless communication technology and the continuous advancement of radar, early warning, detection, guidance and other technologies, antennas as the core components of wireless systems are also constantly developing, playing a vital role in the overall performance of wireless communication systems. During use, the radiation direction of the antenna should be the same as the flight direction of the carrier, so the end-fire antenna structure is adopted. Due to the needs of daily use, the working bandwidth of the antenna must be very wide, so some ordinary antenna structures cannot be used. Although some traditional antennas can achieve ultra-wideband characteristics and stable gain, in order to conform to the carrier system, they must also take into account many issues such as miniaturization, polarization and in-band directional pattern stability, which makes the development of end-fire antennas face challenges. Summary of the invention

[0003] In view of the above-mentioned problems, the present invention proposes an end-fire antenna with a wide beam and stable gain, which realizes the regulation of electromagnetic waves by loading a dielectric coating, a slow-wave structure, an air via, etc., thereby achieving a miniaturized design of the antenna while making the antenna have stable gain and polarization characteristics, and solving the problem of beam upward deviation in a large metal environment.

[0004] The above purpose is achieved through the following technical solutions:

[0005] The invention discloses an end-fire antenna with wide beam and stable gain, comprising an additional covering layer located at an upper layer and an antenna layer located at a lower layer; the antenna layer comprises a SIW third-order ridge waveguide horn printed on a dielectric substrate, a coaxial feed, a slow-wave structure, an air via and an additional ground structure AGS; wherein the outer conductor of the coaxial feed is electrically connected to the lower metal layer of the SIW third-order ridge waveguide horn, and the inner conductor of the coaxial feed is connected to the leftmost end of the first-order ridge of the third-order ridge in the SIW third-order ridge waveguide horn; the slow-wave structure is arranged around the ridge end of the third-order ridge, an air via is provided at a dielectric extension portion at the end of the SIW third-order ridge waveguide horn, and the additional ground structure AGS is loaded at the tail of the dielectric substrate at the lower layer of the extension portion.

[0006] Furthermore, the slow wave structure is realized by sinking grooves on the upper and lower surfaces of the SIW third-order ridge waveguide horn, each sinking groove is equivalent to a series inductor, and adjacent sinking grooves are equivalent to a parallel capacitor, wherein:

[0007] Inductance L is expressed as L = μ r h[ln(h / d)+1 / 2] / π;

[0008] Capacitance C is expressed as C = ε r h2 d / [4πk(h-2d)(pd)];

[0009] Where h is the height of the sink, d is the diameter of the sink, p is the distance between adjacent sinks, μ r is the equivalent magnetic permeability of the medium, ε r is the equivalent dielectric constant of the medium, k = 9.0 × 10 9 N·m 2 / C 2 is the electrostatic force constant;

[0010] Then calculate the propagation constant of electromagnetic waves ω is the angular frequency;

[0011] Therefore, by adjusting the groove depth, groove diameter and spacing between adjacent grooves of the slow-wave structure, the electromagnetic wave propagation constant can be adjusted. The number of grooves in different areas is different, so the equivalent parallel capacitance and series inductance are different. According to the calculation formula of the electromagnetic wave propagation constant, the electromagnetic wave propagation constants in different areas are different. Therefore, the phase of the electromagnetic waves in different areas arriving at the aperture surface can be changed to achieve phase correction at the aperture surface.

[0012] Furthermore, the aperture gradient of the air vias is specifically that the aperture of the air vias in the middle of the horn of the SIW third-order ridge waveguide horn is the smallest, and the aperture gradually increases toward both sides, and the aperture variation range is 1.8mm-2.4mm. The array of the air vias with the aperture gradient variation is equivalent to a dielectric plate with a gradually decreasing dielectric constant. According to the phase calculation formula Among them, ψ is the phase of the electromagnetic wave propagating through the air via, ω is the angular frequency, μ r is the equivalent magnetic permeability of the medium, ε r is the equivalent dielectric constant of the medium, c is the speed of light in a vacuum, and the air via can provide a specific phase for the electromagnetic wave passing through it to compensate for the phase difference between the edge and center of the horn antenna aperture, thereby improving the radiation pattern.

[0013] Furthermore, the additional structure AGS is composed of four mutually separated metal sheets, which are loaded on the right side of the lower surface metal plate, wherein the lower surface metal plate extends 2 mm relative to the upper surface metal plate, the first-order metal sheet is spaced 0.08 mm from the lower surface metal plate, and the interval between adjacent mutually separated metal sheets is also 0.08 mm.

[0014] Furthermore, the additional coating includes an FR4 substrate layer made of a dielectric constant of 4.4, the lower surface of the substrate layer is provided with three spindle-shaped metal parasitic patches and one rectangular metal parasitic patch, and the upper surface of the substrate layer is provided with a metal fence composed of metal patches and metallized vias arranged in a one-dimensional uniform periodic arrangement perpendicular to the aperture direction, and a metal grid arranged in a two-dimensional uniform periodic arrangement along the aperture direction and perpendicular to the aperture direction.

[0015] Furthermore, the diameter of the metallized via in the metal fence is 0.4mm, the width of the metal patch is 1.2mm, and they are arranged at intervals of 1.3mm; the diameter of the metallized via in the metal grid is 0.4mm, and along the aperture direction, the length of the metallized patch is 1.4mm, with an interval of 1.5mm, and the width of the metallized patch along the direction perpendicular to the aperture is 1.2mm, with an interval of 1.3mm.

[0016] Furthermore, the additional covering layer is connected to the antenna layer by a multi-layer board lamination technology.

[0017] Furthermore, the dielectric substrate of the antenna layer adopts F4B with a dielectric constant of 2.2.

[0018] Compared with the prior art, the present invention has the following significant advantages:

[0019] 1. The present invention realizes a miniaturized design by loading a dielectric coating, and improves the pattern degradation problem caused by the miniaturized design by loading a parasitic patch, a slow-wave structure, and an electromagnetic metamaterial, thereby having a smaller size.

[0020] 2. The present invention proposes an additional structure to improve the problem of beam upward deviation in the presence of an extended floor, and has a more stable beam in the target airspace compared to the traditional SIW antenna.

[0021] 3. The present invention has a wider beam width compared with the traditional SIW (substrate integrated waveguide) antenna by improving the beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the overall structure of the SIW horn antenna proposed in the present invention;

[0023] Figure 2 This is a schematic diagram of the antenna layer proposed in the present invention. Figure 2 In the figure, (a) is a top view, and (b) is a cross-sectional view;

[0024] Figure 3 This is a schematic diagram of the additional coating proposed by the present invention. Figure 3 In the figure, (a) is a top view, and (b) is a cross-sectional view;

[0025] Figure 4 The current distribution before and after loading the slow-wave structure, (a) before loading (b) after loading;

[0026] Figure 5 is the azimuth radiation pattern before and after loading the slow-wave structure (7.5GHz);

[0027] Figure 6 Radiation patterns before and after loading metamaterials (17GHz), (a) elevation plane (b) azimuth plane;

[0028] Figure 7 is the radiation pattern before loading AGS;

[0029] Figure 8 Radiation pattern after loading AGS;

[0030] Fig. 9 Radiation pattern after loading AGS, (a) 7.5GHz (b) 9.5GHz (c) 17GHz;

[0031] Fig.10 Radiation pattern of the elevation plane, (a) 6-12GHz (b) 12-18GHz;

[0032] Fig.11 Radiation pattern in azimuth plane, (a) 6-12GHz (b) 12-18GHz;

[0033] Explanation of the reference numerals: 1. antenna layer; 2. additional covering layer; 1-1. SIW third-order ridge waveguide horn; 1-2. coaxial feeding; 1-3. slow-wave structure; 1-4. air via; 1-5. additional ground structure AGS. DETAILED DESCRIPTION

[0034] In the following, in conjunction with the accompanying drawings, an ultra-wideband planar helical antenna with adjustable notch based on an open resonant ring proposed by the present invention is described in detail with reference to a specific embodiment.

[0035] Figure 1 This is a schematic diagram of the overall structure of a wide-beam gain-stable end-fire antenna proposed in the present invention, which mainly consists of two parts, the upper layer is an additional covering layer 2, and the lower layer is an antenna layer 1, and the two layers are connected by multi-layer board lamination technology.

[0036] Figure 2For the antenna layer 1 in the present invention, the dielectric substrate adopts F4B with a dielectric constant of 2.2. It is mainly composed of five parts printed on the dielectric substrate, namely SIW third-order ridge waveguide horn 1-1, coaxial feed 1-2, slow wave structure 1-3, air via 1-4 and additional ground structure AGS1-5. The outer conductor of the coaxial feed 1-2 is electrically connected to the lower metal layer of the SIW third-order ridge waveguide horn 1-1, and the inner conductor of the coaxial feed 1-2 is connected to the leftmost end of the first-order ridge of the SIW third-order ridge waveguide horn 1-1. The slow wave structure 1-3 is arranged around the end of the ridge, and the air via 1-4 is set in the dielectric extension part at the end of the SIW third-order ridge waveguide horn 1-1, and the additional ground structure AGS1-5 is loaded at the tail of the lower floor of the extension part. The slow wave structure is realized by sinking grooves on the upper and lower surfaces of SIW. The adjacent metallized sinking groove structures can be equivalent to an inductor and a capacitor, where the inductor can be expressed as L = μ0h [ln (h / d) + 1 / 2] / π, and the capacitor can be expressed as C = ε0h 2 d / [4πk(h-2d)(pd)], where h is the height of the metallization sink, d is the diameter of the metallization sink, p is the distance between adjacent metallization sinks, μ r is the equivalent magnetic permeability of the medium, ε r is the equivalent dielectric constant of the medium, k = 9.0 × 10 9 N·m 2 / C 2 is the electrostatic force constant; the propagation constant of electromagnetic waves can be calculated ω is the angular frequency. Therefore, by adjusting the groove depth, groove diameter and spacing between adjacent grooves of the slow-wave structure, the electromagnetic wave propagation constant can be adjusted. The number of grooves in different areas is different, so the equivalent parallel capacitance and series inductance are different. According to the calculation formula of the electromagnetic wave propagation constant, the electromagnetic wave propagation constants in different areas are different. Therefore, the phase of the electromagnetic waves in different areas arriving at the aperture surface can be changed to achieve phase correction at the aperture surface. At the same time, the slow-wave structure proposed in the present invention will also have a field concentration effect. As the depth of the metal groove increases, the capacitance effect between the two adjacent metal blocks above and below will increase, so that the electric field is distributed to the two sides of the metal block, so that the purpose of adjusting the electric field intensity distribution on the aperture surface can be achieved. Figure 4 Combining the above two functions, the structure proposed in the present invention can achieve an increase in gain, such as Figure 5As shown. Air vias with a gradient aperture are also loaded at the SIW ridge waveguide horn aperture. The gradient aperture of the air vias is specifically that the air vias in the middle of the SIW third-order ridge waveguide horn have the smallest aperture, and the apertures gradually increase toward both sides. The diameters of the air vias in this embodiment are 1.8mm, 2.2mm, and 2.4mm, respectively, showing a gradient variation. The array arrangement can be equivalent to a dielectric plate with a gradually decreasing dielectric constant, allowing electromagnetic waves to propagate from a high dielectric constant dielectric substrate to a low dielectric constant dielectric substrate, and finally reach free space. It can be equivalent to a metamaterial with a phase shifting function, changing the equivalent dielectric constant of the medium. According to the phase calculation formula Among them, ψ is the phase of the electromagnetic wave propagating through the air via, ω is the angular frequency, μ r is the equivalent magnetic permeability of the medium, ε r is the equivalent dielectric constant of the medium, c is the speed of light in a vacuum, and the air via can provide a specific phase for the electromagnetic wave passing through it to compensate for the phase difference between the edge and center of the horn antenna aperture, thereby improving the radiation pattern, such as Figure 6 As shown, it can be seen that loading the metamaterial effectively improves the antenna gain value and expands the antenna beam width.

[0037] The aperture edge is loaded with an additional ground structure AGS. The proposed AGS consists of four mutually separated metal sheets loaded on the right side of the lower surface metal plate, where the lower surface metal plate extends 2 mm relative to the upper surface metal plate, the first-order metal sheet is spaced 0.08 mm from the lower surface metal plate, and the adjacent mutually separated metal sheets are also spaced 0.08 mm apart, effectively destroying the continuity of the floor. The additional ground structure can be used to achieve beam correction, such as Figure 7 , Figure 8 , Fig. 9 As shown, it can be seen that after loading AGS, the problem of upward deviation of the directional pattern beam is effectively solved.

[0038] Figure 3It is an additional coating in the present invention, and its material is FR4 with a dielectric constant of 4.4. It is mainly composed of two parts, namely three spindle-shaped metal parasitic patches and one rectangular metal parasitic patch located on the lower surface, and a metal fence composed of metal patches and metallized vias arranged in a one-dimensional uniform periodic arrangement perpendicular to the aperture direction and a metal grid arranged in a two-dimensional uniform periodic arrangement along the aperture direction and perpendicular to the aperture direction. The diameter of the metallized via in the metal fence is 0.4mm, the width of the metal patch is 1.2mm, and the arrangement is 1.3mm apart. The diameter of the metallized via in the metal grid is 0.4mm, and along the aperture direction, the length of the metallized patch is 1.4mm, and the interval is 1.5mm. The width of the metallized patch in the direction perpendicular to the aperture is 1.2mm, and the interval is 1.3mm. The parasitic patch is used to adjust the phase at the radiation aperture surface and suppress the generation of high-order modes to improve the radiation performance of the antenna. The metal fence suppresses the surface current at the edge of the SIW upper surface and suppresses the backward radiation caused by the upper surface, thereby improving the front-to-back ratio of the end-fire antenna at low frequencies. The final radiation pattern is shown in the figure below. Fig.10 , 11 As shown, it can be seen that the antenna backward radiation is effectively reduced after adding the additional covering layer.

[0039] The above are only the best embodiments of the present invention, but the present invention is not limited to the above embodiments. The above specific implementation methods are only illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. A wide beam gain stable end-fire antenna, characterized in that: It includes an additional covering layer located on the upper layer and an antenna layer located on the lower layer; the antenna layer includes a SIW third-order ridge waveguide horn printed on a dielectric substrate, a coaxial feed, a slow-wave structure, an air via and an additional ground structure AGS; The outer conductor of the coaxial feed is electrically connected to the lower metal layer of the SIW third-order ridge waveguide horn, and the inner conductor of the coaxial feed is connected to the leftmost end of the first-order ridge of the third-order ridge in the SIW third-order ridge waveguide horn; the slow-wave structure is arranged around the ridge end of the third-order ridge, an air via is provided at the dielectric extension part at the end of the SIW third-order ridge waveguide horn, and an additional ground structure AGS is loaded at the tail of the dielectric substrate under the extension part.

2. The wide beam gain stable end-fire antenna according to claim 1, characterized in that: The slow wave structure is realized by sinking grooves on the upper and lower surfaces of the SIW third-order ridge waveguide horn, each sinking groove is equivalent to a series inductor, and adjacent sinking grooves are equivalent to a parallel capacitor, wherein: Inductance L is expressed as L = μ r h[ln(h / d)+1 / 2] / π; Capacitance C is expressed as C = ε r h 2 d / [4πk(h-2d)(pd)]; Where h is the height of the sink, d is the diameter of the sink, p is the distance between adjacent sinks, μ r is the equivalent magnetic permeability of the medium, ε r is the equivalent dielectric constant of the medium, k = 9.0 × 10 9 N·m 2 / C 2 is the electrostatic force constant; Then calculate the propagation constant of electromagnetic waves ω is the angular frequency; Therefore, by adjusting the groove depth, groove diameter and spacing between adjacent grooves of the slow-wave structure, the electromagnetic wave propagation constant can be adjusted. The number of grooves in different areas is different, so the equivalent parallel capacitance and series inductance are different. According to the calculation formula of the electromagnetic wave propagation constant, the electromagnetic wave propagation constants in different areas are different. Therefore, the phase of the electromagnetic waves in different areas arriving at the aperture surface can be changed to achieve phase correction at the aperture surface.

3. The wide beam gain stable end-fire antenna according to claim 1, characterized in that: The aperture gradient of the air vias is specifically that the aperture of the air vias in the middle of the horn of the SIW third-order ridge waveguide horn is the smallest, and the aperture gradually increases toward both sides, and the aperture variation range is 1.8mm-2.4mm. The array of the air vias with the aperture gradient variation is equivalent to a dielectric plate with a gradually decreasing dielectric constant. According to the phase calculation formula Among them, ψ is the phase of the electromagnetic wave propagating through the air via, ω is the angular frequency, μ r is the equivalent magnetic permeability of the medium, ε r is the equivalent dielectric constant of the medium, c is the speed of light in a vacuum, and the air via can provide a specific phase for the electromagnetic wave passing through it to compensate for the phase difference between the edge and center of the horn antenna aperture, thereby improving the radiation pattern.

4. The wide beam gain stable end-fire antenna according to claim 1, characterized in that: The additional ground structure AGS consists of four mutually separated metal sheets, which are loaded on the right side of the lower surface metal plate, wherein the lower surface metal plate extends 2 mm relative to the upper surface metal plate, the first-order metal sheet is spaced 0.08 mm from the lower surface metal plate, and the interval between adjacent mutually separated metal sheets is also 0.08 mm.

5. The wide beam gain stable end-fire antenna according to claim 1, characterized in that: The additional coating includes an FR4 substrate layer made of a dielectric constant of 4.4, the lower surface of the substrate layer is provided with three spindle-shaped metal parasitic patches and one rectangular metal parasitic patch, the upper surface of the substrate layer is provided with a metal fence composed of metal patches and metallized vias arranged in a one-dimensional uniform periodic arrangement perpendicular to the aperture direction, and a metal grid arranged in a two-dimensional uniform periodic arrangement along the aperture direction and perpendicular to the aperture direction.

6. The wide beam gain-stabilized end-fire antenna according to claim 5, characterized in that: The diameter of the metallized via in the metal fence is 0.4mm, the width of the metal patch is 1.2mm, and they are arranged at intervals of 1.3mm; the diameter of the metallized via in the metal grid is 0.4mm, along the caliber direction, the length of the metallized patch is 1.4mm, the interval is 1.5mm, and the width of the metallized patch along the direction perpendicular to the caliber is 1.2mm, the interval is 1.3mm.

7. The wide beam gain stable end-fire antenna according to claim 1, characterized in that: The additional covering layer is connected to the antenna layer by a multi-layer board lamination technology.

8. The wide beam gain stable end-fire antenna according to claim 1, characterized in that: The dielectric substrate of the antenna layer adopts F4B with a dielectric constant of 2.2.

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