Dual-band end-on-fire antenna based on discone structure

Abstract

The utility model discloses a dual-band end-on-fire antenna based on a discone structure. The dual-band end-on-fire antenna mainly solves the problems that an airborne platform antenna is large in aperture number, large in end-on-fire direction and low in angular domain gain. The antenna comprises a radome (1), an antenna body (2) and a duplexer (3), and the radome (1) is located on the uppermost layer, has a broadband wave-transparent characteristic and is used for protecting a radiation structure in the antenna body; the antenna body (2) is located in the middle layer, comprises a discone, a radiation oscillator, an insulator and a matching body, and is used for transmitting and receiving electromagnetic waves; the disc cone comprises a cone body with an adjustable angular domain range, a mounting flange used for being connected with an antenna housing and an adjusting cavity capable of transmitting dual-band signals, the duplexer (3) is located on the lowest layer and used for transmitting two signals with different frequencies at the same time and isolating the two signals, and it is guaranteed that the antenna can normally work at the same time in the two frequency bands. According to the utility model, the aperture number of the antenna can be reduced, the large angular domain gain in the end-fire direction of the antenna can be improved, the structure is simple, the processing is convenient, and the antenna can be used on an airborne platform.

Description

Technical Field

[0001] This utility model belongs to the field of radar equipment antennas, specifically relating to a dual-band end-fire antenna that can be used on airborne platforms. Background Technology

[0002] With the development of wireless communication technology and the expansion of aircraft functional requirements, more and more radar equipment is being installed on aircraft, resulting in an increasingly high density of airborne radar equipment. Antennas, as the sensor front end of radar equipment, are mounted on the aircraft surface. To accommodate the installation of more radar equipment within limited space, antenna miniaturization and integration are necessary.

[0003] Patent application number 202010747676.2 discloses a microstrip array disk-cone composite conformal antenna. This antenna consists of a disk-cone antenna formed by a metal cone and a metal disk embedded and fixed to the bottom of a reflective cavity. A 2×2 rectangular radiating patch unit is mounted on a dielectric substrate fixed to the metal disk. The rectangular radiating patch unit is fed in parallel through a 1-to-4 microstrip power divider. The disk-cone antenna and the microstrip array antenna form a composite antenna capable of radiating both omnidirectional vertically polarized signals and directional horizontally polarized signals towards the zenith. While this antenna can achieve dual-band composite capability, the maximum gain of the microstrip array antenna points towards the normal direction, resulting in low gain over a large angular range in the end-fire direction. This creates a spatial dead zone during use, failing to meet the communication requirements in the end-fire direction. Furthermore, because this antenna consists of a large number of components, including microstrip array radiating patches, a dielectric substrate, a metal disk, a metal pillar, a metal cone, patch probes, frustum probes, and a reflective cavity, the manufacturing process is relatively complex. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by proposing a dual-band end-fire antenna based on a disc-cone structure, which simplifies the antenna structure and allows a single antenna to simultaneously meet the large-angle range communication requirements of the end-fire direction in two operating frequency bands.

[0005] The technical solution to achieve the purpose of this utility model is as follows:

[0006] A dual-band end-fire antenna based on a disc-cone structure includes an antenna radome 1, an antenna body 2, and a duplexer 3, characterized in that:

[0007] The antenna body 2 includes a disc cone 21, a radiating element 22, an insulator 23, and a matching element 24;

[0008] The disc cone 21 includes a cone 211, a mounting flange 212, and an adjustment cavity 213, with the cone 211 located at the top layer, the mounting flange 212 located in the middle layer, and the adjustment cavity 213 located at the bottom layer.

[0009] The radiating oscillator 22 is located inside the insulator 23, and the two are coaxial;

[0010] The insulator 23 is located directly above the matching body 24, and the two are closely fitted and both are located inside the disc cone 21.

[0011] Furthermore, the cone 211 has a top diameter of φ1, a bottom diameter of φ2, and a height of h1. The distance between the top of the cone and the top of the insulator 23 is h3. By adjusting these parameters, the radiation direction of the antenna can be adjusted so that the angular range of the antenna's end-fire direction meets the design requirements.

[0012] Furthermore, the radiating element 22 has a diameter of φ5 and a height of h4; the insulator 23 has a diameter of φ4 and a height of h5, and h5 is not less than the distance h3 between the top of the cone 211 and the top of the insulator 23, and not greater than the height h4 of the radiating element 22; the parameters of the radiating element 22 and the insulator 23 are adjusted simultaneously to enable the antenna to work in two frequency bands simultaneously.

[0013] Furthermore, the matching body 24 is made of metal and can be any of the following structural forms: stepped, arc-shaped, or conical. It is used to adjust the impedance matching between the disc cone 21, the radiating element 22, and the insulator 23 so that the standing wave coefficient of the antenna meets the design requirements.

[0014] The adjustment cavity 213 has an inner cavity length of L1, a width of W1, a height of h2, and a chamfer radius of R1. The height h2 is not less than the height of the matching body 24. The inner cavity length L1 and width W1 are determined by the transmission characteristics of the rectangular waveguide so that the adjustment cavity 213 can transmit electromagnetic waves of two working frequency bands of the antenna.

[0015] Furthermore, the radome 1 adopts a wideband multi-layer structure and is tightly fixed to the upper surface of the mounting flange 212, so that the upper surface of the mounting flange and the lower surface of the radome are closely fitted. The material is a wave-transparent material to ensure good wave transmission performance in the two working frequency bands of the antenna and reduce the energy loss radiated outward by the antenna.

[0016] Furthermore, the duplexer 3 includes three ports 31, 32, and 33. The first port 31 has the same size as the inner cavity of the adjustment cavity 213 and is tightly connected, so that the upper surface of the duplexer 3 is in close contact with the lower surface of the antenna body 2. The second port 32 and the third port 33 both adopt a rectangular structure, and their size is determined according to the transmission characteristics of the rectangular waveguide so that its transmission frequency meets the requirements of the dual-band operation of the antenna.

[0017] This utility model has the following advantages:

[0018] 1. The antenna body of this utility model adopts a disc-cone structure with wide bandwidth characteristics. Through the combination of the cone, insulator and radiating element, it can not only adjust the angular range of the antenna, but also enable the antenna to work in two frequency bands at the same time, which can fully improve the aperture utilization rate of the airborne platform and reduce the number of antenna apertures.

[0019] 2. Because the present invention introduces a matching element to achieve good impedance matching of the antenna, both operating frequency bands have high gain in the end-fire direction, which meets the end-fire direction communication requirements of radar equipment.

[0020] 3. This utility model has a simple structure, is easy to model and process, and has great practical value. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the antenna body in this utility model;

[0023] Figure 3 This is a schematic diagram of the duplexer structure in this utility model;

[0024] Figure 4 This is a simulation result diagram of the K-band standing wave coefficient of this utility model embodiment;

[0025] Figure 5 This is a simulation result of the K-band radiation pattern of an embodiment of this utility model;

[0026] Figure 6 This is a simulation result diagram of the Ka-band standing wave coefficient of an embodiment of this utility model;

[0027] Figure 7 This is a simulation result of the Ka-band radiation pattern of an embodiment of this utility model. Detailed Implementation

[0028] The embodiments and effects of this utility model will be described in detail below with reference to the accompanying drawings.

[0029] Reference Figure 1 In this embodiment, the antenna includes an radome 1, an antenna body 2, and a duplexer 3. The radome 1 is located on the top layer and has wideband wave transmission characteristics. It is used to protect the internal radiation structure of the antenna and radiate energy outward. The antenna body 2 is located on the middle layer and is used to transmit and receive electromagnetic waves. The duplexer 3 is located on the bottom layer and is used to transmit two signals of different frequency bands simultaneously and to isolate the two signals from each other, ensuring that the antenna can transmit or receive signals of two frequency bands simultaneously.

[0030] In this embodiment, the first operating frequency band is set to, but is not limited to, 24.5GHz to 24.9GHz; the second operating frequency band is set to, but is not limited to, 32.4GHz to 32.8GHz; and the end-radius range of the first and second frequency bands is set to, but is not limited to, -90° to -37° and 37° to 90°.

[0031] In this embodiment, the installation environment is the surface of an airborne platform. The radome 1 is located on the top layer of the antenna and is exposed to the outside of the platform. It needs to meet complex environmental requirements, such as salt spray, mold, and sand dust. The material of the radome is selected to meet the environmental requirements. The radome is preferably a multi-layered structure with a wide bandwidth. Its transmittance T is calculated using the following formula:

[0032]

[0033] in, A i =D i =cosh(jγ) i d i ), B i =Z 0i sinh(jγ i d i ), C i =sinh(jγ) i d i ) / Z 0i ; λ represents the operating frequency, and di represents the thickness of the i-th layer. Let θ represent the complex relative permittivity of the i-th layer. i denoted by , where 'n' represents the number of material layers and 'T' represents the transmission coefficient.

[0034] The radome adopts a three-layer hemispherical curved surface structure, and its material arrangement from the outside to the inside is as follows:

[0035] The first layer material is selected, but is not limited to, cyanate quartz fiber cloth with a dielectric constant of 3.1, a loss tangent of 0.008, and a thickness of 0.3 mm;

[0036] The second layer material may be, but is not limited to, paper honeycomb with a dielectric constant of 1.06, a loss tangent of 0.0035, and a thickness of 2.0 mm.

[0037] The third layer material is selected, but is not limited to, cyanate quartz fiber cloth with a dielectric constant of 3.1, a loss tangent of 0.008, and a thickness of 0.3 mm.

[0038] Substituting the performance parameters of the three materials into the above formula for calculating transmittance, we can see that the transmittance of the radome is greater than 95% in both operating frequency bands, indicating good transmittance performance and low loss of energy radiated outward by the antenna, thus meeting the design requirements.

[0039] refer to Figure 2 The antenna body 2 includes a disc cone 21, a radiating element 22, an insulator 23, and a matching body 24. The disc cone 21 is located on the outermost layer, the radiating element 22 is located inside the insulator 23 and the two are coaxial. The insulator 23 is located directly above the matching body 24, and the two are closely fitted together and both are located inside the disc cone 21. Figure 2 As shown in (a).

[0040] The cone 21 is made of metal and includes a cone 211, a mounting flange 212, and an adjustment cavity 213. The cone 211 is narrower at the top and wider at the bottom, and is located at the top layer. The mounting flange 212 is located in the middle layer, and its upper surface is tightly fitted and fixed to the lower surface of the radome 1. The adjustment cavity 213 is located at the bottom layer and adopts an air cavity structure. The inner cavity has a length of L1, a width of W1, a chamfer radius of R1, and a height of h2, which is not less than the height of the matching body 24. Figure 2 As shown in (b).

[0041] The radiating oscillator 22 is a metal column structure used to radiate electromagnetic waves outward.

[0042] The insulator 23 has a cylindrical structure and is used to isolate the disc cone 21 and the radiating oscillator 22 to make them electrically isolated, avoid current interference between them, and ensure the stability of the radiated signal.

[0043] The matching body 24 is made of metal and can be a stepped structure, an arc-shaped gradient structure, a conical structure, etc. It is used to achieve impedance matching between the disc cone 21, the radiating element 22, and the insulator 23 so that the standing wave coefficient of the antenna meets the design requirements.

[0044] The cone 211 has a top diameter of φ1, a bottom diameter of φ2, a height of h1, and a distance of h3 between the top of the cone and the top of the insulator 23. The radiating element 22 has a diameter of φ5 and a height of h4, and the insulator 23 has a diameter of φ4 and a height of h5. The height h5 is not less than the distance h3 between the top of the cone and the top of the insulator 23, and not greater than the height h4 of the radiating element. By adjusting these parameters through simulation, the dual-band operation requirements and angular range requirements of the antenna can be met, and the antenna's radiation characteristics can be optimized.

[0045] refer to Figure 3 The duplexer 3 is a three-port waveguide device, with its three ports being the first port 31, the second port 32, and the third port 33.

[0046] The cavity size of the first port 31 is the same as the inner cavity size of the adjustment cavity 213, and the two are tightly connected, so that the upper surface of the duplexer 3 is in close contact with the lower surface of the antenna body 2.

[0047] Both the second port 32 and the third port 33 adopt a rectangular structure, and the internal cavity size is determined according to the above-mentioned formula for the transmission characteristics of rectangular waveguides. Their operating frequencies meet the requirements of the first and second frequency bands of the antenna, respectively.

[0048] When the antenna of this invention is working, it can transmit and receive simultaneously on two frequency bands, or transmit on one frequency band and receive on the other. When the antenna is in the transmitting state, the signal transmitted by the back-end radar equipment selects a suitable port from the second port 32 and the third port 33 according to its operating frequency band and enters the duplexer. Then, it enters the adjustment cavity 213 of the antenna body through the first port 31 of the duplexer 3, and reaches the radiating dipole 22 through the matching body 24, where it is converted into electromagnetic waves. Finally, it is radiated outward through the radome 1. When the antenna is in the receiving state, the incoming electromagnetic waves pass through the radome 1 and are received by the radiating dipole 22 of the antenna body 2. Then, they enter the adjustment cavity 213, reach the first port 31 of the duplexer 3 through the matching body 24, and finally reach the back-end radar equipment through the second port 32 or the third port 33 of the duplexer 3.

[0049] As an example, the parameter settings for each component of the antenna of this utility model are as follows:

[0050] The cone 211 has a top diameter φ1 of 22 mm, a bottom diameter φ2 of 38.8 mm, a cone height h1 of 11 mm, and a distance h3 between the top of the cone and the insulator 23 of 8.15 mm.

[0051] Mounting flange 212, its diameter φ3 is 59mm;

[0052] The adjustment cavity 213 has an inner length L1 of 8.636 mm, a width W1 of 4.318 mm, a chamfer radius R1 of 1 mm, and a height h2 of 11 mm.

[0053] The radiating oscillator 22 has a diameter φ5 of 1 mm and a height h4 of 10.95 mm.

[0054] Insulator 23 is made of, but is not limited to, polytetrafluoroethylene with a dielectric constant of 2.08 and a loss tangent of 0.021, with a diameter φ4 of 3 mm and a height h5 of 9.95 mm.

[0055] Matching body 24 adopts a 3-step structure, with the first step measuring 3.2mm×3mm, the second step measuring 2.4mm×3mm, and the third step measuring 1.3mm×3mm;

[0056] The duplexer 3 has a first port 31 with the same internal cavity size as the adjustment cavity 213, namely, a length of 8.636 mm, a width of 4.318 mm, and a chamfer radius of 1 mm; the second port 32 operates at a frequency of 24.5 GHz to 24.9 GHz, and the internal cavity length is calculated to be, but not limited to, 8.636 mm and the width is, but not limited to, 4.318 mm, based on the transmission characteristics of the rectangular waveguide.

[0057] The third port 33 operates at a frequency of 32.4GHz to 32.8GHz, and its internal cavity length is, but is not limited to, 7.112mm and its width is, but is not limited to, 3.556mm.

[0058] The inner cavity length L1 and width W1 of the adjustment cavity 213 are calculated according to the following formula for the transmission characteristics of a rectangular waveguide:

[0059]

[0060] In the formula It is the cutoff wavelength of transverse electric waves with guided mode indices m and n. It is the cutoff wavelength of a transverse magnetic wave with guided mode indices m and n, where m and n are two arbitrary positive integers representing the guided mode indices.

[0061] Since the condition for a guided mode to transmit in a waveguide is that the cutoff wavelength is greater than the operating wavelength, and since this invention includes two operating frequency bands, the aforementioned cutoff wavelength should be greater than both operating wavelengths simultaneously.

[0062] In this example, the dominant mode for rectangular waveguide transmission is TE. 10 That is, m=1, n=0. Based on the working wavelength of the given working frequency band, the minimum cutoff wavelength can be obtained as 12.25mm. Substituting into the above formula, we can obtain the inequality: L1>6.125mm;

[0063] Based on the other structural dimensions of this example, select appropriate values ​​as the initial value of L1, and set the width W1 to be half of the length L1, that is, in this example, L1 is 8.636mm and the width W1 is 4.318mm.

[0064] The parameters of the radiating element 22 and the insulator 23 were determined through simulation optimization. First, an antenna model was built in the simulation software. Then, the parameters of the radiating element 22 and the insulator 23 were set as variables. By changing these variables, the simulation results of the antenna radiation patterns in the two frequency bands were compared. Finally, one set of parameters that met the design requirements of the simulation results was selected.

[0065] The parameters of the matching body 24 are determined by simulation optimization. First, an antenna model is established in the simulation software. Then, the dimensions of the three steps of the matching body 24 are set as variables. By changing these variables, the simulation results of the antenna standing wave coefficient are compared. One of the variables that meets the design requirements is taken as the final parameter value.

[0066] The effectiveness of this invention can be further illustrated by the following simulation results.

[0067] I. Simulation Conditions

[0068] The electromagnetic simulation model of this embodiment of the invention was established using HFSS electromagnetic simulation software and the above-mentioned example parameters. Its operating frequency bands are K-band and Ka-band.

[0069] II. Simulation Content

[0070] Simulation 1: The K-band standing wave coefficient of the electromagnetic simulation model of this embodiment is simulated, and the results are as follows. Figure 4 .

[0071] from Figure 4 It can be seen that the standing wave ratio of the antenna is 1.2127 at the center frequency of 24.7GHz, and the maximum standing wave ratio in the 24.5GHz to 24.9GHz frequency band is 1.2283, corresponding to the frequency of 24.9GHz. This indicates that the standing wave ratio of the K-band of the antenna of this utility model is less than 1.23 in the range of 24.5GHz to 24.9GHz.

[0072] Simulation 2: The K-band radiation pattern of the antenna electromagnetic simulation model of this embodiment is simulated, and the results are as follows. Figure 5 .

[0073] from Figure 5 As can be seen, the minimum gain of the antenna in the -90° to -37° angular range is 1.4247dB, corresponding to an angle of -90°; the minimum gain of the antenna in the 37° to 90° angular range is 1.6040dB, corresponding to an angle of 90°. This indicates that the gain of the antenna of this invention is greater than 1.4dB in both the -90° to -37° angular range and the 37° to 90° angular range in the K-band end-fire direction.

[0074] Simulation 3: The Ka-band standing wave coefficient of the antenna electromagnetic simulation model of this embodiment is simulated, and the results are as follows: Figure 6 .

[0075] from Figure 6It can be seen that the standing wave ratio (SWR) of the antenna is 1.1539 at a center frequency of 32.6 GHz, and the maximum SWR in the 32.4 GHz to 32.8 GHz band is 1.1969, corresponding to a frequency of 32.4 GHz. This indicates that the Ka-band SWR of the antenna of this invention is less than 1.20 in the 32.4 GHz to 32.8 GHz range.

[0076] Simulation 4: The Ka-band radiation pattern of the antenna electromagnetic simulation model of this embodiment is simulated, and the results are as follows. Figure 7 .

[0077] from Figure 7 As can be seen, the minimum gain of the antenna in the -90° to -37° angular range is 1.3732dB, corresponding to an angle of -90°; the minimum gain of the antenna in the 37° to 90° angular range is 1.2431dB, corresponding to an angle of 90°. This indicates that the antenna of this invention has a gain greater than 1.2dB in the Ka-band end-fire direction in the -90° to -37° angular range and the 37° to 90° angular range.

[0078] The simulation results above verify that the dual-band end-fire antenna based on the disk-cone structure of this invention has the advantages of low standing wave ratio, simultaneous operation in two frequency bands, and high gain in the large angular domain of the end-fire direction, and has broad application prospects on airborne equipment platforms.

[0079] The above description is merely a specific example of this utility model and does not constitute any limitation on this utility model. Obviously, those skilled in the art, after understanding the content and principle of this utility model, may make various modifications and changes in form and details without departing from the principle and structure of this utility model. For example, in addition to the stepped structure used in this embodiment, the structure of the matching body can also adopt an arc-shaped gradient structure or a conical structure. The radome adopts a multi-layer structure, the number of layers is not limited to three, and the structural shape is not limited to a hemispherical curved surface. These modifications and changes based on the concept of this utility model are still within the scope of protection of the claims of this utility model.

Claims

1. A dual-band end-fire antenna based on disc-cone structure, comprising a radome (1), an antenna body (2), and a duplexer (3), characterized in that: the antenna body (2) comprises a disc-cone (21), a radiation oscillator (22), an insulator (23), and a matching body (24); the disc-cone (21) comprises a cone (211), a mounting flange (212), and an adjusting cavity (213), wherein the cone (211) is located at the uppermost layer, the mounting flange (212) is located at the middle layer, and the adjusting cavity (213) is located at the lowermost layer; the radiation oscillator (22) is located inside the insulator (23) and coaxial with the insulator (23); the insulator (23) is located directly above the matching body (24), and the two are tightly attached and located inside the disc-cone (21); the parameters of the radiation oscillator (22) and the insulator (23) are adjusted simultaneously to enable the antenna to work at two frequency bands simultaneously; the parameters of the cone (211) and the distance between the top of the cone (211) and the top of the insulator (23) are adjusted to adjust the radiation direction of the antenna, so that the angular range of the end-fire direction of the antenna meets the design requirements.

2. The antenna according to claim 1, characterized in that, The top diameter of the cone (211) is φ1, the bottom diameter is φ2, the height is h1, the distance between the top of the cone (211) and the top of the insulator (23) is h3, and the radiation direction of the antenna can be adjusted by adjusting these parameters.

3. The antenna of claim 1, characterized in that: the diameter of the radiation oscillator (22) is φ5, and the height is h4; the diameter of the insulator (23) is φ4, and the height is h5, wherein h5 is not less than the distance h3 between the top of the cone (211) and the top of the insulator (23), and not greater than the height h4 of the radiation oscillator (22); adjusting these parameters of the radiation oscillator (22) and the insulator (23) ensures that the antenna can work at two frequency bands simultaneously.

4. The antenna according to claim 1, wherein, The matching body (24) is made of metal and has any one of the following structures: stepped, arc-shaped gradually changing, and cone, which is used to adjust the impedance matching between the disc-cone (21), the radiation oscillator (22), and the insulator (23), so that the standing wave coefficient of the antenna meets the design requirements.

5. The antenna according to claim 1, wherein, The adjusting cavity (213) has an inner cavity length L1, a width W1, a height h2, and a chamfer radius R1, wherein the height h2 is not less than the height of the matching body (24), and the inner cavity length L1 and the width W1 are determined by the transmission characteristics of the rectangular waveguide, so that the adjusting cavity (213) can transmit electromagnetic waves at two working frequency bands of the antenna.

6. The antenna according to claim 1, wherein, The radome (1) has a wide-band multi-layer structure and is tightly fixed to the upper surface of the mounting flange (212), so that the upper surface of the mounting flange and the lower surface of the radome are tightly attached, and the material of the radome is selected from wave-transparent materials, so that the antenna has good wave-transparent performance in the two working frequency bands and reduces the energy loss of the antenna's outward radiation.

7. The antenna according to claim 1, wherein, The duplexer (3) comprises three ports (31, 32, 33), namely a first port (31), a second port (32) and a third port (33); wherein the first port (31) is consistent with the inner cavity size of the adjusting cavity (213) and is fastened and connected, so that the upper surface of the duplexer (3) is closely attached to the lower surface of the antenna body (2); the second port (32) and the third port (33) both adopt a rectangular structure, the size of which is determined according to the transmission characteristics of the rectangular waveguide, so that the transmission frequency meets the working requirements of the antenna dual-frequency band.

8. The antenna according to claim 3, wherein, The adjusting radiator (22) and the insulator (23) are set as variables in the simulation software, the antenna model is established, the parameters of the adjusting radiator (22) and the insulator (23) are set as variables, the simulation results of the antenna two-frequency band patterns are compared by changing the variables, and the parameter adjustment is completed when the simulation results of one set of parameters meet the design requirements.

9. The antenna according to claim 4, wherein, The matching body (24) realizes impedance matching between the adjusting disc cone (21), the adjusting radiator (22) and the insulator (23), the shape and the specific size of the matching body (24) are set as variables in the simulation software, the simulation result change image of the standing wave coefficient of the antenna is compared by changing the variables, and the impedance matching is completed when the simulation results of one set of variables meet the design requirements.

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