X-band high power horn antenna based on equal-power feeding ridge waveguide

Abstract

This invention discloses a high-power horn array antenna based on equal-power-division ridged waveguide feeding, characterized by high power capacity and high gain. A 4:1 unequal power distribution is achieved in the BJ100 waveguide placed along its short side by loading a cylindrical inductive post offset 5.2 mm from the branch centerline. Based on stepped impedance matching theory, an inductive module offset 5.2 mm from the branch centerline is loaded at the ridged waveguide branch to achieve a 4:1 unequal power distribution in the ridged waveguide placed along its long side. The antenna is entirely filled with sulfur hexafluoride gas to achieve even higher power capacity. A waveguide transition structure is applied to achieve a transmission transition between the standard rectangular waveguide and the ridged waveguide, and a metal plate is added to reduce the back lobe of the antenna pattern and improve the main lobe gain. The antenna feeding structure uses a standard BJ100 waveguide and its ridged waveguide, both with a waveguide wall thickness of 1.27 mm. This invention achieves a power capacity greater than 1MW in the 9.35~9.65 GHz frequency band, and within a 312mm×312mm aperture plane, the center frequency gain is greater than 29.6dBi, and the aperture efficiency across the entire frequency band is greater than 75%.

Description

Technical Field

[0001] This invention belongs to the field of antenna engineering technology, specifically relating to an X-band high-power horn antenna based on equal power splitter ridge waveguide feeding. Background Technology

[0002] In recent years, high-power antennas have seen significant development, particularly in the field of high-power microwave (HPM) technology. HPM technology is widely used to disrupt the electronic equipment of enemy airborne targets to counter various aerial threats. Especially with the rapid development of drones, defending against low-altitude, slow-moving drones has become a major challenge. Laser weapons are easily affected by weather and terrain, making the radiation of high-power-density electromagnetic waves without self-damage the optimal solution. Traditional high-power antennas, such as Vlasov antennas, TEM horn antennas, and lens antennas, all employ single antenna structures, making it impossible to array them for unified feeding. Traditional waveguide power dividers can only achieve equal power distribution, and operations such as adding spacers can only achieve a small 2:1 power unequal distribution and cannot be applied to ridged waveguides. Based on these shortcomings, a new type of high-power antenna has emerged in recent years. Unlike traditional single high-power antennas, this new high-power antenna utilizes a common pyramidal horn antenna for easy arraying, applying cylindrical inductive columns and inductive modules to standard waveguides and ridged waveguides respectively to achieve a large-amplitude power unequal distribution. This type of horn array antenna combines multiple advantages such as high power capacity, high gain, all-metal integrated molding, and array capability.

[0003] In 2022, the paper "Design of high power microwave active phased array antenna unit" proposed a high-power horn antenna using a pyramidal horn antenna as its core component and a coaxial-to-waveguide converter for connecting the antenna to an SMA connector. The design employs a square coaxial block to increase the power capacity of the coaxial probe. The pyramidal horn design achieves a power capacity of 15.88 kW, 70.81% higher than a standard antenna. It also supports wide-angle scanning and maintains a VSWR of less than 1.9 in the 7.5–8.8 GHz frequency range. However, because this design directly feeds a single horn antenna through a coaxial interface, it suffers from limitations such as the inability to feed the entire horn array from a single port, limited power capacity, and a relatively high VSWR.

[0004] In patent CN113193321A, the inventors proposed a 1-to-7 waveguide power divider, achieving equal power distribution within the 22-32GHz frequency range. This design employs cylindrical and frustum-shaped structures to achieve a 2:1 unequal power distribution, thus solving the technical problems of narrow effective operating bandwidth and complex design in existing power dividers, especially odd-path waveguide power dividers. It can achieve full bandwidth transmission within its operating frequency band under various standard waveguide dimensions through reasonable configuration. However, it is difficult to achieve large-amplitude unequal power distribution, and the signal amplitude and phase consistency between the output ports are poor, with the ports not lying on the same plane and excessively large spacing.

[0005] In patent CN116190961B, the inventors designed a power divider and combiner using multi-stage stepped impedance transformation technology to address the poor signal amplitude and phase consistency between output ports. This achieved insertion loss <0.57dB, phase difference <9.7°, and VSWR <1.33 in the 35-40GHz frequency range. The added DGS structure in this scheme effectively suppresses out-of-band harmonics, significantly reducing interference. However, the unequal power division amplitude of this power divider still needs further expansion, making it difficult to meet the needs of large-amplitude unequal power distribution, and the power capacity is not specified.

[0006] To address the aforementioned problems, this invention discloses an X-band high-power horn antenna based on equal power divider and ridge waveguide feeding, aiming to achieve breakthroughs in increasing power capacity, increasing unequal power divider amplitude, reducing element spacing, and realizing antenna arraying. Summary of the Invention

[0007] The purpose of this invention is to address the challenges of traditional high-power antennas, such as difficulties in arraying, limited power capacity (kW level), and the inability to achieve MW-level power capacity. Traditional unequal power dividers also suffer from poor signal amplitude and phase consistency between output ports, as well as excessive distances. This invention achieves a 4:1 unequal power distribution and excellent impedance matching within a standard rectangular waveguide power divider by loading cylindrical inductive pillars. To prevent grating lobes, a ridged waveguide structure is used to compress the array spacing of the horn elements. Based on stepped impedance matching theory, inductive modules are added at the branches of the ridged waveguide to control the power ratio between the two branches and improve impedance matching. The antenna is entirely filled with sulfur hexafluoride gas to achieve even higher power capacity. A total power capacity greater than 1MW is achieved in the 9.35~9.65 GHz frequency band, with a center frequency gain greater than 29.6dBi and an overall aperture efficiency greater than 75% within a 312mm×312mm aperture plane.

[0008] To achieve the aforementioned objectives, the present invention employs the following technical solution: a high-power horn array antenna based on equal-power divided ridge waveguide feeding. This antenna array comprises a pyramidal horn antenna 100, a ridge waveguide transition structure 101 with a gradient line, a metal ground plane 102 mounted below the antenna, a 1-to-10 power divider 200 using a ridge waveguide, a cuboid inductive module 201 mounted in a single-ridge waveguide and connected to the ridge, a 1-to-10 power divider 300 using a BJ100 waveguide, and a cylindrical inductive column 301 mounted in a standard waveguide and connected to the upper and lower walls of the waveguide.

[0009] First, an all-metal horn antenna was designed. Since the total antenna aperture was required to be less than 312mm × 312mm, to facilitate the subsequent design of the equal power divider, it was initially considered to arrange 2 power-law antenna elements in each row. Initially, the horn aperture was set to 39mm × 39mm, with 8 elements placed on each side. Since this horn aperture is 1.2 times the wavelength corresponding to the center frequency of 9.5GHz, it can be seen from the grating lobe calculation formula (1) that the array will generate grating lobes when side-firing. Therefore, the horn aperture was adjusted to 31.2mm × 31.2mm, forming a 10 × 10 horn antenna array.

[0010] (1)

[0011] Furthermore, the first-stage 1-to-10 power divider unit structure is constructed using a standard BJ100 waveguide (22.86mm × 10.16mm) with the short side placed, and a wall thickness of 1.27mm. At the second power distribution point, a cylinder connecting the inner walls of the upper and lower waveguides is added. By controlling its position relative to the branch centerline, when the cylindrical induction column shifts towards one port, the energy fed from the input port becomes unequally distributed, with the port closer to the induction column outputting less energy. This achieves stepless adjustment of the power ratio between the two branches. When the cylindrical induction column is 5.2mm from the branch centerline, a large 4:1 unequal power distribution is achieved. At other power distribution points, the cylindrical induction columns are placed at the branch centerline, achieving a 1:1 equal power distribution and improving impedance matching.

[0012] Furthermore, since 100 speakers need to be uniformly fed through a single waveguide port, 10 power dividers using standard BJ100 waveguides must be connected. However, another dimension requires placement along the long side of the BJ100 waveguide, which is not feasible due to the size limitations of the speaker units. Therefore, a ridge-adding method is used to reduce the waveguide size. To simplify the optimization and manufacturing process, a single ridge is used. However, after adding a single ridge to the waveguide, it is no longer possible to achieve power distribution and improve impedance matching through cylindrical inductive columns. Therefore, according to the stepped impedance matching theory, an inductive module is added to the power distribution point of the ridged waveguide. By controlling its position relative to the branch centerline, when the metal inductive module is offset towards one side of the port, the energy fed from the input port is unevenly distributed. The port closer to the inductive module outputs less energy, thereby achieving stepless adjustment of the power ratio between the two branches. When the metal inductive module is 5.2mm away from the branch centerline, a large 4:1 unequal power distribution is achieved. The cuboid inductive modules at other power distribution points are all placed at the branch centerline to achieve a 1:1 equal power distribution and improve impedance matching.

[0013] Furthermore, to connect the standard waveguide and the ridged waveguide, a transition structure with a gradient line was designed, which has an insertion loss of less than 0.08dB and good impedance matching characteristics. The above-mentioned ridged waveguide 1-to-10 power divider, transition structure and pyramidal horn are connected, and a metal ground plane is added below the horn to improve the main lobe gain. The BJ100 waveguide 1-to-10 power divider, transition structure and ridged waveguide 1-to-10 power divider are connected. The antenna aperture size is 312mm×312mm, the cross-sectional height of the pyramidal horn is 25mm, the cross-sectional height of the standard BJ100 waveguide 1-to-10 power divider is 173.7mm, and the cross-sectional height of the ridged waveguide 1-to-10 power divider is 171.5mm. The power capacity of the horn antenna is calculated, and the calculation formula is shown in Equation (2), where the input power is... Set to 1W, The breakdown field strength of sulfur hexafluoride gas (60 kV / cm) This represents the actual maximum field strength of the model. The maximum field strength of the horn antenna at three typical frequency points is as follows: Figures 16-18 As shown, the calculated power capacity at 9.35 GHz is 0.35 MW, at 9.5 GHz is 0.19 MW, and at 9.65 GHz is 0.134 MW.

[0014] (2)

[0015] The horn antenna, waveguide, inductive module, and sensing post are all made of aluminum. The horn antenna, waveguide transition structure, ridged waveguide, and standard waveguide are connected by welding.

[0016] In summary, this antenna design has the following innovations: (1) It improves the traditional design concept of a single high-power antenna by using a waveguide-based unified feed to form an antenna array, thereby increasing the total power capacity of the system; (2) It uses a relatively simple pyramidal horn antenna as the transmitting unit, simplifying the design and manufacturing process; (3) It loads cylindrical induction columns at the branch of the BJ100 waveguide 1-to-10 power divider to achieve a 4:1 large-amplitude unequal power distribution; (4) It adds inductive modules at the branch of the single-ridge waveguide 1-to-10 power divider to achieve a 4:1 large-amplitude unequal power distribution; (5) It uses chamfered, cylindrical induction columns and inductive modules to improve impedance matching, thereby improving the amplitude and phase consistency of the 1-to-10 power divider and the aperture efficiency of the antenna across the entire frequency band. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a high-power horn array antenna element fed by a ridged waveguide with equal power distribution. The elements include: a pyramidal horn antenna 100; a ridged waveguide transition structure 101 with a tapered line; a metal ground plane 102 below the antenna; a 1-to-10 power divider 200 using a ridged waveguide; a cuboid inductive module 201 loaded in a single-ridged waveguide and connected to the ridge; a 1-to-10 power divider 300 using a BJ100 waveguide; and a cylindrical inductive column 301 loaded in a standard waveguide and connected to the upper and lower walls of the waveguide.

[0018] Figure 2 This is a schematic diagram of a pyramidal horn structure, fed by a standard BJ100 waveguide, with the horn diameter adjusted to 31.2mm × 31.2mm and the cross-sectional height to 25mm.

[0019] Figure 3 The diagram shows the structure of the BJ100 waveguide 1-to-10 equal power divider. First, it performs a 1-to-2 equal power divider, then performs an unequal power divider to achieve a 4:1 unequal power divider. Finally, it performs two more 1-to-2 equal power dividers to achieve a 1-to-10 equal power divider.

[0020] Figure 4 This is a schematic diagram of the transition structure, using a gradient line to achieve the connection between the ridged waveguide and the standard waveguide.

[0021] Figure 5 This diagram shows a ridge waveguide 1-to-10 power divider, transition structure, and horn structure under one-dimensional periodic conditions. A metal ground plane is added below the horn to improve the main lobe gain.

[0022] Figure 6 and Figure 7 The scans are of the E and H planes of a horn with an aperture of 31.2mm × 31.2mm, respectively. Simulation results of standing waves within the range.

[0023] Figure 8The simulation results show the transmission coefficient of a 1-to-10 power divider using the BJ100 waveguide.

[0024] Figure 9 The simulation results show the transmission phase of a 1-to-10 power divider using the BJ100 waveguide.

[0025] Figure 10 The simulation results show the transmission coefficients of the transition structure.

[0026] Figure 11 This is the normal gain result obtained after post-processing when an array of a ridged waveguide-based 10-to-10 power divider and a horn antenna is formed under one-dimensional periodic boundary conditions.

[0027] Figure 12 The simulation results show the normal gain of a 10*10 finite-sized loudspeaker array.

[0028] Figures 13-15 The gain patterns of a 10*10 finite array at 9.35GHz, 9.5GHz, and 9.65GHz are shown respectively.

[0029] Figures 16-18 The field strength distributions of a 10*10 finite array at frequencies of 9.35GHz, 9.5GHz, and 9.65GHz, respectively, are given when the input power is 1W. Detailed Implementation

[0030] like Figure 1 As shown, this embodiment is a high-power horn array antenna based on equal power divided ridge waveguide feeding, which consists of a pyramidal horn antenna 100, a ridge waveguide transition structure 101 with a gradient line, a metal ground plane 102 loaded below the antenna, a 1-to-10 power divider 200 using a ridge waveguide, a cuboid inductive module 201 loaded in a single ridge waveguide and connected to the ridge, a 1-to-10 power divider 300 using a BJ100 waveguide, and a cylindrical inductive column 301 loaded in a standard waveguide and connected to the upper and lower walls of the waveguide.

[0031] The horn antenna, metal ground plane, waveguide, inductive module, and sensing column are all made of aluminum. The horn antenna, metal ground plane, waveguide transition structure, ridged waveguide, and standard waveguide are connected by welding, and the wall thickness of each is 1.27mm.

[0032] The BJ100 waveguide employs a 1:1 power distribution structure, but due to horn size limitations, only the short side can be used. Cylindrical induction posts connected to the upper and lower walls of the waveguide are used. When the cylindrical induction post is 5.2mm from the branch centerline, a large 4:1 unequal power distribution is achieved. For other power distribution points, the cylindrical induction posts are placed at the branch centerline to achieve a 1:1 equal power distribution and improve impedance matching.

[0033] To uniformly power 100 speakers through a single waveguide port, 10 of them must be connected to a single waveguide port. Figure 3 The diagram shows a 1-to-10 power divider connected using a BJ100 waveguide. However, another dimension requires placement along the long side of the BJ100 waveguide. Due to the size limitations of the speaker unit, this could not be achieved. Therefore, a single ridge was added to the center of the long side of the rectangular waveguide. The ridge is 6.8mm wide and 3.3mm deep, reducing the waveguide size from 22.86mm × 10.16mm to 12mm × 5.4mm, allowing 10 1-to-10 power dividers using the BJ100 waveguide to be connected. However, adding the ridge reduces the waveguide's power capacity, therefore this power divider can only be used as a second-stage 1-to-10 power divider.

[0034] A ridged waveguide with equal power distribution of 1 to 10 is adopted. Due to the structural limitations of the ridge, a metallic inductive module is added to the branch waveguide. By controlling its position relative to the branch centerline, the port closer to the inductive module outputs less energy, thereby achieving stepless adjustment of the power ratio between the two branches. When the metallic inductive module is 5.2mm away from the branch centerline, a large 4:1 unequal power distribution is achieved. The metallic inductive modules at other power distribution points are placed at the branch centerline to achieve a 1:1 equal power distribution and improve impedance matching.

[0035] The antenna aperture size is 312mm×312mm, the profile height of a single horn is 25mm, the profile height of a 1-to-10 power divider using BJ100 waveguide is 173.7mm, the profile height of a 1-to-10 power divider using ridged waveguide is 171.5mm, and the overall profile height is 370mm.

[0036] Figure 6 and Figure 7 The simulation results of standing wave (SWR) for E-plane and H-plane scanning of a horn with an aperture of 31.2mm × 31.2mm are shown. It can be seen that within the 9.35 ~ 9.65 GHz frequency band, the E-plane and H-plane scanning... The standing wave ratio within the range is less than 1.3, achieving good matching performance.

[0037] Figure 8 The simulation results of the transmission coefficient of the 1 to 10 power divider using the BJ100 waveguide show that the transmission coefficient between the input port and the ten output ports is greater than -10.95dB in the frequency band, the insertion loss is less than 1dB, and the impedance matching characteristics are good.

[0038] Figure 9 The simulation results of the transmission phase of the 1 to 10 power divider using the BJ100 waveguide show that the transmission phase difference between the input port and the ten output ports is less than 8 degrees in the frequency band, indicating good phase consistency.

[0039] Figure 10The simulation results of the transmission coefficient of the transition structure show that the insertion loss is less than 0.08dB in the 9.35 ~ 9.65GHz frequency band, and the impedance matching characteristics are good.

[0040] Figure 11 This paper presents the post-processing results of the normal gain obtained after assembling an array of a 1×10 power divider with a ridged waveguide and a horn antenna under one-dimensional periodic boundary conditions. A 1×10 array was used, and post-processing under periodic boundary conditions yielded array gains of 29.5 dBi@9.35 GHz, 30.68 dBi@9.5 GHz, and 31.07 dBi@9.65 GHz, indicating good cross-polarization performance.

[0041] Figure 12 The simulation results for the normal gain of a 10*10 finite-gain horn array are shown. The gain of the finite-gain array is 30.29dBi@9.35GHz; 29.80dBi@9.5GHz; 29.84dBi@9.65GHz. It has good cross-polarization performance and aperture efficiency greater than 75% at typical frequencies.

[0042] Figures 13-15 The gain patterns of the finite array at 9.35 GHz, 9.5 GHz, and 9.65 GHz are shown respectively. The beamform is good and the cross-polarization performance is good.

[0043] Figures 16-18 The field strength distribution of the finite array at 9.35GHz, 9.5GHz and 9.65GHz respectively, when the input power is 1W, is obtained from the calculation formula (2). The power capacity at 9.35GHz is 2.12MW, the power capacity at 9.5GHz is 1.6MW and the power capacity at 9.65GHz is 1.07MW.

[0044] The embodiments described above are merely illustrative of specific implementations of the present invention. Their descriptions are detailed and specific, and should be understood as being presented only as examples and not as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. An X-band high-power horn antenna based on equal power-dividing ridge waveguide feeding, characterized in that, The device includes a pyramidal horn antenna (100), a ridged waveguide transition structure (101) with a gradient line, a metal ground plane (102) loaded below the antenna, a 1-to-10 power divider (200) using a ridged waveguide, a cuboid inductive module (201) loaded in a single-ridged waveguide and connected to the ridge, a 1-to-10 power divider (300) using a BJ100 waveguide, and a cylindrical inductive column (301) loaded in a standard BJ100 waveguide and connected to the upper and lower walls of the waveguide. The horn antenna, waveguide, ground plane, inductive module, and inductive column are all made of aluminum. The horn antenna, ground plane, waveguide transition structure, ridged waveguide, and standard waveguide are connected by welding.

2. The X-band high-power horn antenna based on equal power-dividing ridge waveguide feeding according to claim 1, characterized in that... Cylindrical induction posts connected to the upper and lower walls of the BJ100 waveguide are used. When the cylindrical induction post is 5.2mm away from the branch centerline, a large 4:1 unequal power distribution is achieved in the BJ100 waveguide. The cylindrical induction posts at other power distribution points are placed at the branch centerline to achieve a 1:1 equal power distribution in the BJ100 waveguide and improve impedance matching.

3. The X-band high-power horn antenna based on equal power-dividing ridge waveguide feeding according to claim 1, characterized in that... A cuboid inductive module connected to the ridge of the ridged waveguide is used. When the metal inductive module is 5.2mm away from the branch centerline, a large 4:1 unequal power distribution is achieved in the ridged waveguide. The metal inductive modules at other power distribution points are placed at the branch centerline to achieve a 1:1 equal power distribution in the ridged waveguide and improve impedance matching.

4. The X-band high-power horn antenna based on equal power-dividing ridge waveguide feeding according to claim 1, characterized in that... By using waveguides as power dividers and filling them with sulfur hexafluoride gas, a power capacity greater than 1MW within the operating frequency band is achieved. By placing a 1-to-10 power divider using BJ100 waveguides in the first stage and a 1-to-10 power divider using ridged waveguides in the second stage, the problem of reduced waveguide power capacity after ridge addition is solved. The outer edges of the right angles of the waveguides are rounded to improve impedance matching. A transition structure is used to connect the standard waveguide and the ridged waveguide.

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