Broadband high-integration substrate integrated waveguide horn antenna

Abstract

The invention discloses a broadband high-integration substrate integrated waveguide horn antenna, and relates to the technical field of communication, in particular to the antenna technology, the broadband high-integration substrate integrated waveguide horn antenna comprises a dielectric coating and an antenna layer structure, and the antenna layer structure comprises a substrate integrated waveguide horn and a loading structure which are printed on a dielectric substrate. The loading structure also comprises a bias parallel double-sided structure with an etching gap and a defected ground structure; the substrate integrated waveguide horn is composed of a semi-open resonant cavity expanded by a substrate integrated waveguide H surface, a coaxial feed structure and a three-order ridge structure; the offset parallel double-sided structures etched with the gaps are distributed right in front of the horn mouth of the substrate integrated waveguide horn, and the defected ground structures are distributed on the horn aperture edge of the substrate integrated waveguide horn, specifically two pairs of symmetrical gaps etched on the upper surface of the antenna layer dielectric substrate. The antenna has the excellent characteristics of high integration level, stable end fire and wide frequency band, and is suitable for conformal integration application on small aircrafts.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to a broadband highly integrated substrate integrated waveguide horn antenna. Background Art

[0002] With the rapid development of modern science and technology, society needs wider bandwidth and easier to install or carry antennas to transmit the explosive growth of information. Therefore, the overall performance of the antenna has an important impact on the operation of the entire system. Traditional H-plane horn antennas are widely used in wireless communications due to their wide bandwidth, stable end-fire characteristics and other properties, but their non-planar structure limits their further application in miniaturization and integration. The emerging microwave transmission technology, substrate integrated waveguide technology, can solve this problem well, allowing traditional H-plane horn antennas to achieve planar design. However, due to the mismatch of the dielectric constant between the substrate integrated waveguide substrate and the air, the designed antenna bandwidth is narrow and it is difficult to meet the requirements of broadband communication. Therefore, how to achieve wide bandwidth and small size while maintaining good radiation performance of the horn antenna is of great research value.

[0003] In order to expand the broadband of substrate-integrated waveguide horn antennas, existing technologies include: changing the profile of the traditional H-plane horn to a super-elliptical taper, introducing an extended dielectric plate that can serve as an impedance transformer in front of the horn aperture, and loading air holes with gradient diameter changes or printed transition structures on the extended dielectric plate. However, the above technologies will increase the size of the antenna, which is not conducive to installation and use in limited space.

[0004] In view of the above problems, the present invention provides a substrate integrated waveguide ridge horn antenna with two sets of slots etched in an offset parallel double-sided structure and defect ground. Through the loading of the unique structure, not only the antenna bandwidth is significantly expanded, but also the antenna volume is kept small and the end-fire radiation performance is stable, meeting the needs of broadband wireless communication. Summary of the invention

[0005] The present invention discloses a broadband highly integrated substrate integrated waveguide horn antenna, which effectively broadens the antenna bandwidth and improves the end-fire performance of the antenna, and has the excellent characteristics of high integration.

[0006] The above purpose is achieved through the following technical solutions:

[0007] A broadband highly integrated substrate integrated waveguide horn antenna comprises a dielectric coating and an antenna layer structure, wherein the antenna layer structure comprises a substrate integrated waveguide horn and a loading structure printed on a dielectric substrate, wherein the loading structure further comprises an offset parallel double-sided structure of etched slits and a defective ground structure, wherein the substrate integrated waveguide horn is composed of a semi-open resonant cavity widened by the H-surface of the substrate integrated waveguide, a coaxial feeding structure and a third-order ridge structure; the inner conductor of the coaxial feeding structure is in contact with the upper ridge of the third-order ridge structure, and the outer conductor of the coaxial feeding structure is in contact with the lower bottom surface of the dielectric substrate; the offset parallel double-sided structure of the etched slits is distributed in front of the horn mouth of the substrate integrated waveguide horn, and the defective ground structure is distributed at the horn aperture edge of the substrate integrated waveguide horn, specifically two pairs of symmetrical slits etched on the upper surface of the antenna layer dielectric substrate.

[0008] Furthermore, the semi-open resonant cavity is formed by a metal through hole with a diameter of 0.4 mm along a semicircular arc with a radius of r1 and four extension segments arranged equidistantly, the lengths of the four extension segments are l1, l2, l3, l4, respectively, w1, w2, w3 are widths at different positions, and the opening angle of the resonant cavity is adjusted by adjusting the lengths of l1, l2, l3, l4, the widths w1, w2, w3 at different positions, and the size of each ridge of the three-order ridge structure, thereby adjusting the antenna impedance and realizing a broadband substrate integrated waveguide horn;

[0009] The opening width of the substrate integrated waveguide horn is derived from the geometric relationship of the horn mouth:

[0010]

[0011] Where δ is the adjustment coefficient and λ is the wavelength of electromagnetic wave propagation in the dielectric substrate:

[0012]

[0013] where μ r and ε r is the relative dielectric constant and relative magnetic permeability of the dielectric substrate FR4, λ0 is the wavelength of the electromagnetic wave in free space;

[0014] The opening angle of the substrate integrated waveguide horn is calculated using the following formula: The calculation formula is as follows:

[0015] Furthermore, the adjustment coefficient is generally set to a value of 0.1-0.4λ.

[0016] Furthermore, the offset parallel double-sided structure of the etched slots is a structure in which four parallel surface structures are arranged on the front and back surfaces of the dielectric substrate distributed in front of the horn mouth of the substrate integrated waveguide horn, and the four parallel surface structures on the front and back surfaces include two pairs of parallel surfaces etched with T-shaped slots and two pairs of parallel surfaces etched with umbrella-shaped slots, and the sizes of each two pairs of parallel surface structures are the same, wherein the T-shaped slot pattern on the front and back surfaces of the dielectric substrate has an offset distance of 0.5 mm on the x-axis; the umbrella-shaped slot pattern on the front and back surfaces of the dielectric substrate has an offset distance of 1 mm on the x-axis.

[0017] Furthermore, the defective structure is specifically two pairs of slits symmetrical along the y-axis etched on the upper surface of the antenna layer dielectric substrate; distributed at the edge of the horn aperture of the substrate integrated waveguide horn, wherein the slit away from the horn aperture edge is 3 mm long and 0.1 mm away from the end of the horn aperture edge, the second slit is approximately 0.5 mm apart from the first slit, and the length is 2 mm.

[0018] Furthermore, the dielectric substrate in the antenna layer structure adopts a 2.6 mm thick F4B board with a dielectric constant of 2.65;

[0019] Furthermore, the dielectric coating is made of a 1.1 mm thick FR4 board with a dielectric constant of 4.4.

[0020] Compared with the prior art, the present invention has the following significant advantages:

[0021] 1) The biased parallel double-sided structure with two sets of slots etched in the load makes the real part of the antenna impedance closer to 50Ω and the imaginary part closer to 0Ω in the X and Ku bands, thus achieving broadband characteristics;

[0022] 2) The defect-loaded ground structure optimizes the end-fire performance of the antenna and reduces the backward radiation;

[0023] 3) It has the characteristics of small size, light weight, easy integration and easy conformality. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a top view of the antenna structure;

[0025] Figure 2 It is a side view of the antenna structure;

[0026] Figure 3 A substrate-integrated waveguide horn structure;

[0027] Figure 4 Schematic diagram of the substrate integrated waveguide horn structure

[0028] Figure 5 Loading and etching of offset parallel double surfaces with gaps;

[0029] Figure 6Schematic diagram of the loading bias parallel double-sided structure;

[0030] Figure 7 Comparison diagram of standing wave ratio and impedance after biasing parallel double-sided structure in the embodiment;

[0031] Figure 8 A comparison diagram of the standing wave ratio after etching the first group of slits in the embodiment;

[0032] Fig. 9 A comparison diagram of surface current distribution after etching the first group of slits in the embodiment;

[0033] Fig.10 This is a comparison diagram of the standing wave ratio and impedance after etching the second group of slits in the embodiment;

[0034] Fig.11 This is a schematic diagram of the structure after the defective ground is loaded in the embodiment;

[0035] Fig.12 The defective structure of the embodiment changes the aperture edge current direction diagram;

[0036] Fig.13 A comparison diagram of antenna gain and backward radiation after a defective ground structure is loaded in the embodiment;

[0037] Fig.14 is a result diagram of the antenna shown in the embodiment;

[0038] Description of the component numbers in the figure:

[0039] 1. Antenna layer structure; 2. Dielectric cladding; 1-1. Dielectric substrate; 1-2. Substrate integrated waveguide horn; 1-3. Loading structure; 1-3-1. Biased parallel double-sided structure; 1-3-2. Defective ground structure; 1-2-1. Semi-open resonant cavity; 1-2-2. Coaxial feeding structure; 1-2-3. Third-order ridge structure. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0041] This embodiment provides a broadband, highly integrated substrate integrated waveguide horn antenna. Figure 1 and Figure 2 As shown, the size of the antenna is about 1.4λ0×0.8λ0×0.16λ0, Figure 1 The l and w above correspond to the length and width of the antenna, respectively, l = 1.4λ0, w = 0.8λ0, where λ0 is the wavelength of the electromagnetic wave in free space, which is the ratio of the speed of light c to the frequency f:

[0042] λ0=c / f

[0043] The broadband highly integrated substrate integrated waveguide horn antenna of this embodiment is composed of a dielectric coating 2 and an antenna layer structure 1, wherein the dielectric coating adopts a 1.1 mm thick FR4 board with a dielectric constant of 4.4; wherein the antenna layer structure 1 includes a substrate integrated waveguide horn 1-2 and a loading structure 1-3 printed on a dielectric substrate 1-1, and in this embodiment, the dielectric substrate adopts a 2.6 mm thick F4B board with a dielectric constant of 2.65; the loading structure further includes an offset parallel double-sided structure 1-3-1 with etched gaps and a defective ground structure 1-3-2.

[0044] The substrate integrated waveguide horn 1-2 is composed of a semi-open resonant cavity 1-2-1 widened by the H-surface of the substrate integrated waveguide, a coaxial feeding structure 1-2-2 and a third-order ridge structure 1-2-3. Figure 3 As shown; the inner conductor of the coaxial feeding structure 1-2-2 is in contact with the upper ridge of the third-order ridge structure 1-2-3, and the outer conductor of the coaxial feeding structure 1-2-2 is connected to the lower bottom surface of the dielectric substrate 1-1; the semi-open resonant cavity 1-2-1 is formed by a metal through hole with a diameter of 0.4 mm along a semicircular arc with a radius of r1 and four extension sections arranged equidistantly, Figure 4 The l1, l2, l3, l4 shown are the lengths of each extension segment, and w1, w2, w3 are the widths at different positions. The opening angle of the resonant cavity is adjusted by adjusting the lengths l1, l2, l3, l4 of each extension segment, the widths w1, w2, w3 at different positions, and the size of each ridge of the three-order ridge structure to adjust the antenna impedance and realize a wide-band substrate integrated waveguide horn.

[0045] The opening width of the substrate integrated waveguide horn 1-2 can be derived from the geometric relationship of the horn mouth as follows:

[0046]

[0047] The value of δ is generally 0.1-0.4 electrical lengths, and δ = 0.22λ. Considering that the antenna should be as small as possible, l1,

[0048] The sum of l2, l3, and l4 is 1.2λ, where λ is the wavelength of electromagnetic wave propagation in the dielectric substrate:

[0049]

[0050] where μ r and ε r is the relative dielectric constant and relative magnetic permeability of the dielectric substrate FR4; further, it can be deduced that w3 is about 17mm, and the opening angle can be calculated using the following formula It is about 30°, and the calculation formula is as follows:

[0051]

[0052] The three-order ridge structure with gradually decreasing height is adjusted directly through optimization simulation. In this embodiment, the sizes of the three ridge sections along the radiation direction are 6.2mm*4.1mm*1.6mm, 5.3mm*3.8mm*1.2mm, and 1.8mm*3.2mm*0.6mm respectively.

[0053] Figure 5 The schematic diagram of the structure of the biased parallel double-sided structure 1-3-1 is shown. The biased parallel double-sided structure 1-3-1 is distributed in front of the horn mouth of the substrate integrated waveguide horn and is located on both sides of the dielectric substrate, wherein four parallel surface structures are respectively arranged on the front and back sides of the dielectric substrate, and the four parallel surface structures on the front and back sides include two pairs of parallel surfaces etched with T-shaped gaps and two pairs of parallel surfaces etched with umbrella-shaped gaps. The dimensions of every two pairs of parallel surface structures of the dielectric substrate are the same, and the lengths lp1 and lp2 are approximately 5 mm, and the widths wp1 and wp2 are approximately 8 mm. In this embodiment, the horn mouth direction of the parallel substrate integrated waveguide horn on the dielectric substrate is taken as the x-axis, and the y-axis perpendicular to the horn mouth direction of the parallel substrate integrated waveguide horn is established to explain.

[0054] The parallel surface etched with the T-shaped gap is 1.3 mm away from the upper edge of the dielectric substrate g2, and the gap between the substrate integrated waveguide horn is about 0.2 mm. The T-shaped gap pattern on the front and back sides of the dielectric substrate has an offset distance of 0.5 mm on the x-axis; the two pairs of parallel surfaces etched with umbrella-shaped gaps are close to the upper right corner of the dielectric substrate, and the interval g3 along the x-axis is 1.5 mm; the umbrella-shaped gap pattern on the front and back sides of the dielectric substrate has an offset distance of 1 mm on the x-axis.

[0055] The biased parallel double-sided structure adjusts the input impedance of the antenna at low and medium frequencies, and expands the frequency band of the antenna to low frequencies, such as Figure 7 shown.

[0056] The T-shaped gap is divided into two parts s1 and s2, such as Figure 6 As shown; s1 is 2.5mm long, 0.2mm wide, and 1.9mm away from the starting edge g1 of the parallel plane along the y-axis. A 3mm long gap s2 is connected to the end of s1 along the x-axis. A high-frequency resonance point at 17.4GHz is introduced by etching the first group of gaps, and the bandwidth of the antenna is extended to high frequencies, as shown in FIG. Figure 8 The results show that Fig. 9 From the perspective of the current distribution diagram, it is intuitively shown that the antenna has high-frequency resonance at the first group of gaps.

[0057] The umbrella-shaped gap is divided into two parts s3 and s4, such as Figure 6As shown; s3 is about 3mm away from the left side of the parallel plane g4, the gap is 3mm long, s4 is a semicircular gap with a diameter of 3mm, and the center of the circle is located at the top of s3; by introducing the second group of gaps, the input impedance of the antenna at medium and high frequencies is further optimized, so that the overall input impedance of the antenna is closer to 50Ω in the real part and closer to 0Ω in the imaginary part, which optimizes the matching performance of the antenna and thus broadens the antenna bandwidth, as shown in FIG. Fig.10 shown.

[0058] Fig.11 Schematic diagram after loading defective ground structure 1-3-2. Defective ground structure 1-3-2 is distributed at the edge of the speaker aperture, specifically two pairs of slits symmetrical along the y-axis etched on the upper surface of the antenna layer dielectric substrate; the slit away from the speaker is 3mm long and about 0.1mm away from the end of the speaker. The distance between the second slit and the first is about 0.5mm, and the length is 2mm; Fig.12 As shown in the figure, the loading structure changes the current flow direction at the edge of the horn aperture, which significantly reduces the backward radiation without deteriorating the antenna gain and improves the end-fire performance of the antenna. The result is shown in Fig.13 middle.

[0059] The standing wave ratio and gain results of the antenna provided by the present invention are shown in Fig.14 In the figure, it can be seen that broadband is achieved while maintaining good radiation performance.

[0060] 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 broadband, highly integrated substrate-integrated waveguide horn antenna, comprising a dielectric coating and an antenna layer structure, characterized in that: The antenna layer structure includes a substrate integrated waveguide horn and a loading structure printed on a dielectric substrate, the loading structure further includes an offset parallel double-sided structure of etched gaps and a defective ground structure, the substrate integrated waveguide horn is composed of a semi-open resonant cavity widened by the H-plane of the substrate integrated waveguide, a coaxial feeding structure and a third-order ridge structure; the inner conductor of the coaxial feeding structure is in contact with the upper ridge of the third-order ridge structure, and the outer conductor of the coaxial feeding structure is in contact with the lower bottom surface of the dielectric substrate; the offset parallel double-sided structure of the etched gaps is distributed in front of the horn mouth of the substrate integrated waveguide horn, and the defective ground structure is distributed at the edge of the horn aperture of the substrate integrated waveguide horn, specifically two pairs of symmetrical gaps etched on the upper surface of the antenna layer dielectric substrate.

2. A broadband highly integrated substrate integrated waveguide horn antenna according to claim 1, characterized in that: The semi-open resonant cavity is formed by a metal through hole with a diameter of 0.4 mm along a semicircular arc with a radius of r1 and four extension segments arranged equidistantly, the lengths of the four extension segments are l1, l2, l3, l4, w1, w2, w3 are the widths at different positions, and the opening angle of the resonant cavity is adjusted by adjusting the lengths of l1, l2, l3, l4, the widths w1, w2, w3 at different positions, and the size of each ridge of the three-order ridge structure, thereby adjusting the antenna impedance and realizing a broadband substrate integrated waveguide horn; The opening width of the substrate integrated waveguide horn is derived from the geometric relationship of the horn mouth: Where δ is the adjustment coefficient and λ is the wavelength of electromagnetic wave propagation in the dielectric substrate: where μ r and ε r is the relative dielectric constant and relative magnetic permeability of the dielectric substrate FR4, λ0 is the wavelength of the electromagnetic wave in free space; The opening angle of the substrate integrated waveguide horn is calculated using the following formula: The calculation formula is as follows:

3. The broadband highly integrated substrate integrated waveguide horn antenna according to claim 2, characterized in that: The adjustment coefficient is generally 0.1-0.4λ.

4. The broadband highly integrated substrate integrated waveguide horn antenna according to claim 1, characterized in that: The offset parallel double-sided structure of the etched slots is that four parallel surface structures are arranged on the front and back surfaces of the dielectric substrate distributed in front of the horn mouth of the substrate integrated waveguide horn, and the four parallel surface structures on the front and back surfaces include two pairs of parallel surfaces etched with T-shaped slots and two pairs of parallel surfaces etched with umbrella-shaped slots. The sizes of each two pairs of parallel surface structures are the same, wherein the T-shaped slot patterns on the front and back surfaces of the dielectric substrate have an offset distance of 0.5 mm on the x-axis; and the umbrella-shaped slot patterns on the front and back surfaces of the dielectric substrate have an offset distance of 1 mm on the x-axis.

5. The broadband highly integrated substrate integrated waveguide horn antenna according to claim 1, characterized in that: The defective ground structure is specifically two pairs of slits symmetrical along the y-axis etched on the upper surface of the antenna layer dielectric substrate; distributed at the edge of the horn aperture of the substrate integrated waveguide horn, wherein the slit far away from the horn aperture edge is 3 mm long and 0.1 mm away from the end of the horn aperture edge; the second slit is about 0.5 mm apart from the first slit and has a length of 2 mm.

6. The broadband highly integrated substrate integrated waveguide horn antenna according to claim 1, characterized in that: The dielectric substrate in the antenna layer structure adopts a 2.6 mm thick F4B board with a dielectric constant of 2.65; 7. The broadband highly integrated substrate integrated waveguide horn antenna according to claim 1, characterized in that: The dielectric coating is a 1.1 mm thick FR4 board with a dielectric constant of 4.4.

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