A dual-polarized open waveguide array antenna capable of large-angle beam deflection

Abstract

The application discloses a dual-polarized open waveguide array antenna capable of realizing large-angle beam deflection, comprising a metal cavity, a series feed power division network, a columnar Teflon dielectric block and a coaxial feed probe. The series feed network is adopted to feed and phase shift, so that the array directional diagram beam realizes fixed-angle 30-degree deflection. Two feed networks are used to feed the same metal cavity to realize + / -45-degree polarization switching, polarization unit multiplexing is realized, the antenna size is reduced by opening the metal cavity and adding the columnar Teflon dielectric block, so that the grating lobe generation is suppressed when large-angle beam deflection is performed. The array has the advantages of low cost, simple structure, small size, convenient polarization switching, easy realization of large-angle beam deflection and the like.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology, specifically a dual-polarized open waveguide array antenna capable of achieving large-angle beam deflection. Background Technology

[0002] Waveguide array antennas are widely used in radar and communication fields due to their high efficiency, ease of fabrication, and high structural strength. With engineering demands, various types of waveguide array antennas have been developed. Among them, waveguide slot array antennas are widely used because their aperture distribution is easy to control, they easily achieve low sidelobes, high efficiency, and compact structure. However, the bandwidth of waveguide slot antenna arrays is relatively narrow, which cannot meet the requirements for large bandwidth. Open waveguide antennas, on the other hand, have a very wide bandwidth, and antennas using open waveguides as radiating elements are rarely reported. Common open waveguide antennas are generally single-polarized; however, with changing application scenarios, the requirement for dual polarization is increasing. Therefore, how to maintain the advantages of open waveguide antennas while achieving dual-polarization performance is a key research focus. Furthermore, in some application scenarios, certain requirements are placed on the beam deflection angle of open waveguide antenna arrays. However, under large-angle beam deflection, because the size of open waveguide antennas and element sizes are too large, large grating lobes are often generated during beam deflection. The key to avoiding this problem is to shorten the cell spacing, so miniaturization of cell size is particularly important. Summary of the Invention

[0003] The purpose of this invention is to provide a dual-polarized open waveguide array antenna that can achieve large-angle beam deflection, addressing the needs of existing technologies.

[0004] The technical solution to achieve the purpose of this invention is as follows: a dual-polarized open waveguide array antenna capable of large-angle beam deflection, the antenna comprising a rectangular metal cavity, a plurality of columnar Teflon dielectric blocks uniformly distributed along the central axis of the rectangular metal cavity, and two series-feed power dividers located on both sides of the columnar Teflon dielectric blocks and symmetrical about the central axis, and further comprising two coaxial feed probes extending into the rectangular metal cavity to feed the two series-feed power dividers respectively; the number of columnar Teflon dielectric blocks is the same as the number of output ports of a single series-feed power divider, each output port of each series-feed power divider is connected to a plurality of columnar Teflon dielectric blocks in a one-to-one correspondence, and the output ports of the two series-feed power dividers connected to the same columnar Teflon dielectric block are perpendicular to each other.

[0005] Furthermore, the output ports of the series-fed power divider have equal amplitudes and their phases decrease linearly sequentially.

[0006] Furthermore, the series-fed power divider network includes a main waveguide and several V-shaped E-plane waveguides uniformly distributed along the length of the main waveguide. One end of the main waveguide serves as an input port, and one end of each V-shaped E-plane waveguide is connected to the main waveguide, while the other end serves as an output port.

[0007] Furthermore, the main waveguide is arranged parallel to the central axis of the rectangular metal cavity, and along the direction perpendicular to the central axis of the rectangular metal cavity, the width of the main waveguide decreases in a stepped manner, that is, the characteristic impedance decreases in a stepwise manner.

[0008] Furthermore, one end of each V-shaped E-plane waveguide is connected to the width transition point of the main waveguide, and along the direction in which the width of the main waveguide decreases sequentially, the length of the E-plane waveguide connected to the columnar Teflon dielectric block in the V-shaped E-plane waveguide decreases sequentially, while the length of the E-plane waveguide connected to the main waveguide increases sequentially.

[0009] Furthermore, the spacing between the columnar Teflon dielectric blocks is less than half a free space wavelength.

[0010] Furthermore, the columnar Teflon dielectric block is installed in a radiation hole opened in the rectangular metal cavity.

[0011] Furthermore, the top of the columnar Teflon medium block is at the same height as the top of the rectangular metal cavity.

[0012] Furthermore, the bottom of the series-fed power divider network is at the same height as the bottom of the columnar Teflon dielectric block.

[0013] Furthermore, the coaxial feed probe is located on the center line of the wide side of the main waveguide of the series feed power divider network.

[0014] Compared with the prior art, the significant advantages of this invention are:

[0015] 1) By feeding the radiation hole and the two vertical sides adjacent to the chamfer inside the metal cavity, two polarization waves of ±45° are introduced without adding any elements, thus realizing the dual polarization of the antenna.

[0016] 2) By setting two 1-to-4 series power distribution networks inside the metal cavity, independent control of the two polarization waves can be achieved.

[0017] 3) By placing a Teflon dielectric block inside the metal cavity, the wavelength of the electromagnetic wave is shortened, thereby enabling the miniaturization of the waveguide and the reduction of the spacing between antenna elements, thus meeting the requirement of not generating grating lobes when the beam deflects at large angles.

[0018] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a dual-polarized open waveguide array antenna that can achieve large-angle beam deflection in one embodiment.

[0020] Figure 2 This is a schematic diagram of port allocation in a serial feed power divider network in one embodiment.

[0021] Figure 3 This is a simulation diagram of the input port S11 of the series-fed power divider network in one embodiment.

[0022] Figure 4 This is a simulation diagram of the amplitude of the output ports S12, S13, S14, and S15 of the series-fed power divider network in one embodiment.

[0023] Figure 5 This is a simulation diagram of the phases of the output ports S12, S13, S14, and S15 of the series-fed power divider network in one embodiment.

[0024] Figure 6 This is a simulation diagram of the input ports S11 and S22 of the antenna array in one embodiment.

[0025] Figure 7 This is a simulation diagram of the input port isolation S12 of the antenna array in one embodiment.

[0026] Figure 8 This is an example of an antenna array beam deflection pattern.

[0027] Figure 9 This is the antenna array beam pattern when one port is fed in one embodiment.

[0028] Figure 10 This is the antenna array beam pattern when port two is fed in one embodiment. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0030] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0031] In one embodiment, combined Figure 1 and Figure 2A dual-polarized open waveguide array antenna capable of large-angle beam deflection is provided. The antenna includes a rectangular metal cavity 1, four columnar Teflon dielectric blocks 3 uniformly distributed along the central axis of the rectangular metal cavity 1, and two series-feed power dividers 2 located on both sides of the columnar Teflon dielectric blocks 3 and symmetrical about the central axis. It also includes two coaxial feed probes 4 extending into the rectangular metal cavity 1 to feed the two series-feed power dividers 2 respectively. The number of columnar Teflon dielectric blocks is the same as the number of output ports of a single series-feed power divider 2. Each output port of each series-feed power divider 2 is connected to a number of columnar Teflon dielectric blocks 3 in a one-to-one correspondence, and the output ports of the two series-feed power dividers 2 connected to the same columnar Teflon dielectric block 3 are perpendicular to each other.

[0032] Furthermore, in one embodiment, the output ports of the series-feed power divider network 2 have equal amplitudes and their phases decrease linearly in sequence, which can achieve antenna beam deflection.

[0033] Furthermore, in one embodiment, the columnar Teflon dielectric block 3 is installed in a radiation hole opened inside the rectangular metal cavity 1.

[0034] Preferably, the radiation hole is a cube with chamfered corners, and the cross-sectional dimensions of the columnar Teflon dielectric block are the same as those of the radiation hole.

[0035] Preferably, the top of the columnar Teflon dielectric block 3 is flush with the radiation aperture and at the same height as the top of the rectangular metal cavity 1. The introduction of the dielectric block reduces the size of the radiation aperture, thereby reducing the size of the antenna element by about 1.4 times at the same resonant frequency, and correspondingly reducing the element spacing by about 1.4 times, thus ensuring that no grating lobes appear in the antenna array when the beam deflects at large angles.

[0036] Preferably, the spacing between the columnar Teflon dielectric blocks 3 is less than half a free space wavelength.

[0037] More preferably, the output ports corresponding to the two series-fed power dividers 2 are respectively perpendicular to the two adjacent vertical sides of the right chamfer of the columnar Teflon dielectric block 3. Here, the two adjacent vertical sides of the chamfer of the radiation hole inside the metal cavity are fed respectively, thereby introducing another polarization without increasing the number of units and realizing the polarization multiplexing of the units.

[0038] Furthermore, in one embodiment, the series-fed power divider network 2 includes a main waveguide and a plurality of V-shaped E-plane waveguides uniformly distributed along the length of the main waveguide. One end of the main waveguide serves as an input port (input port 1), and one end of each V-shaped E-plane waveguide is connected to the main waveguide, while the other end serves as an output port (output ports 2 to 5).

[0039] The main waveguide is arranged parallel to the central axis of the rectangular metal cavity 1, and along the direction perpendicular to the central axis of the rectangular metal cavity 1, the width of the main waveguide decreases in a stepped manner, that is, the characteristic impedance decreases in a stepwise manner.

[0040] One end of each of the V-shaped E-plane waveguides is connected to the width transition point of the main waveguide, and along the direction in which the width of the main waveguide decreases sequentially, the length of the E-plane waveguide connected to the columnar Teflon dielectric block 3 in the V-shaped E-plane waveguide decreases sequentially, while the length of the E-plane waveguide connected to the main waveguide increases sequentially.

[0041] In this embodiment, the energy ratio of output ports 2 to 5 is 1:1:1:1. Because the output energy of the E-plane waveguide series-fed 1-to-2 power divider is proportional to its characteristic impedance—that is, the greater the output energy, the greater the corresponding characteristic impedance—and simultaneously, the characteristic impedance is proportional to the waveguide width, therefore, the further back the power divider is, the narrower the corresponding waveguide becomes. During energy distribution, the phase of the power divider's output ports also changes. According to the phased array principle, to achieve a certain beam tilt, the phase of the output ports is adjusted to decrease linearly in sequence.

[0042] Furthermore, in one embodiment, the coaxial feed probe is composed of a metal probe and a Teflon dielectric, located at the middle position of the series feed power divider network along the height direction, with two coaxial probes symmetrically distributed and extending into the waveguide, thereby completing the conversion from the coaxial line TEM mode to the waveguide TE10 mode.

[0043] Preferably, the coaxial power supply probe 4 adopts an SMA connector in practice, and the flange of the connector is fixed to the side wall of the rectangular metal cavity 1 by metal screws.

[0044] Furthermore, in one embodiment, the rectangular metal cavity 1 is made of 3D-printed stainless steel material, and the entire structure is integrally formed, which can prevent the leakage of electric field energy.

[0045] As a specific example, the invention will be further described in one embodiment.

[0046] In this example, the cylindrical Teflon dielectric block 3 has a dielectric constant of 2.1 and a loss tangent of 0.001, and is manufactured by machining. The port distribution of the series-fed power divider network 2 is as follows. Figure 2 As shown, port 1 is the input port, and ports 2 to 5 are the output ports.

[0047] Depend on Figure 3 It can be seen that the S11 of this power divider is below -20dB in the 30-40GHz frequency range, indicating good matching performance.

[0048] Depend on Figure 4It can be seen that near 35GHz, S12 = -5.85dB, S13 = -5.99dB, S14 = -6.15dB, and S15 = -6.22dB, and the maximum fluctuation of the output port is 0.36dB, which basically meets the requirement of equal amplitude distribution.

[0049] Depend on Figure 5 It can be seen that near 35GHz, cang_S12=-134.39°, cang_S13=-232.01°, cang_S14=28.06°, and cang_S15=-72.16°, with an average phase difference of 99° between ports. The maximum amplitude of phase fluctuation above and below this is 1.5°, which basically meets the requirement of linear phase distribution. In summary, the series-fed power divider network (2) has excellent port amplitude and phase performance, which can meet the requirements of beam deflection.

[0050] Regarding antenna performance, such as Figure 6 As shown, the antenna's S11 and S22 values ​​are both less than -15dB in the 34GHz–36GHz range, indicating that the antenna can achieve good impedance matching characteristics within this frequency band. Due to the symmetry of the structure, the impedance matching characteristics of the two ports are identical, meaning that the S11 and S22 curves essentially overlap. Figure 7 As shown, the isolation S12 at the antenna ports is less than -20dB in the 34GHz to 36GHz range, indicating good isolation between the two ports. A typical 3D radiation pattern of this antenna is shown below. Figure 8 As shown, the antenna achieves a certain beam deflection angle. When fed from both ports, the radiation pattern curves of the antenna on the beam deflection tangent are as follows: Figure 9 , Figure 10 As shown, in the 35GHz antenna pattern, the beam is deflected at theta = -30°. The maximum gain when the two ports are fed separately is 11.18dBi and 11.21dBi, respectively, with a fluctuation of only 0.03dBi, indicating good consistency between the ports. The sidelobe levels in the pattern are -9.89dB and -9.58dB, respectively, which is also good.

[0051] This invention proposes a dual-polarized open waveguide array antenna capable of large-angle beam deflection. It employs a series-feed network for feeding and phase shifting, enabling a fixed 30° deflection of the array's beam pattern. Two feeding networks power the same metal cavity to achieve ±45° polarization switching, realizing polarization element multiplexing. By opening the metal cavity and adding cylindrical Teflon dielectric blocks, the antenna size is reduced, thereby suppressing grating lobe generation during large-angle beam deflection. This array offers advantages such as low cost, simple structure, small size, easy polarization switching, and ease of achieving large-angle beam deflection.

[0052] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention without departing from its spirit and scope should be included within the protection scope of the present invention.

Claims

1. A dual-polarized open waveguide array antenna capable of achieving large-angle beam deflection, characterized in that, The antenna includes a rectangular metal cavity (1), a plurality of columnar Teflon dielectric blocks (3) uniformly distributed along the central axis of the rectangular metal cavity (1) within the rectangular metal cavity (1), and two series feed power dividers (2) located on both sides of the columnar Teflon dielectric blocks (3) and symmetrical about the central axis. It also includes two coaxial feed probes (4) extending into the rectangular metal cavity (1) to feed the two series feed power dividers (2) respectively. The number of columnar Teflon dielectric blocks is the same as the number of output ports of a single series feed power divider (2). Each output port of each series feed power divider (2) is connected to a plurality of columnar Teflon dielectric blocks (3) in a one-to-one correspondence, and the output ports of the two series feed power dividers (2) connected to the same columnar Teflon dielectric block (3) are perpendicular to each other. The output port signals of the series-fed power divider network (2) have equal amplitudes and their phases decrease linearly in sequence. The series-fed power divider network (2) includes a main waveguide and several V-shaped E-plane waveguides uniformly distributed along the length of the main waveguide. One end of the main waveguide serves as an input port, and one end of each V-shaped E-plane waveguide is connected to the main waveguide, while the other end serves as an output port. The main waveguide is arranged parallel to the central axis of the rectangular metal cavity (1), and along the direction perpendicular to the central axis of the rectangular metal cavity (1), the width of the main waveguide decreases in a step-like manner, that is, the characteristic impedance decreases in a step-like manner. One end of each of the V-shaped E-plane waveguides is connected to the width jump point of the main waveguide, and along the direction in which the width of the main waveguide decreases sequentially, the length of the E-plane waveguide connected to the columnar Teflon dielectric block (3) in the V-shaped E-plane waveguide decreases sequentially, while the length of the E-plane waveguide connected to the main waveguide increases sequentially. The top of the columnar Teflon medium block (3) is at the same height as the top of the rectangular metal cavity (1).

2. The dual-polarized open waveguide array antenna capable of large-angle beam deflection according to claim 1, characterized in that, The spacing between the columnar Teflon dielectric blocks (3) is less than half a free space wavelength.

3. The dual-polarized open waveguide array antenna capable of large-angle beam deflection according to claim 1, characterized in that, The columnar Teflon medium block (3) is installed in the radiation hole opened in the rectangular metal cavity (1).

4. The dual-polarized open waveguide array antenna capable of large-angle beam deflection according to claim 1, characterized in that, The bottom of the series-fed power divider network (2) is at the same height as the bottom of the columnar Teflon dielectric block (3).

5. The dual-polarized open waveguide array antenna capable of large-angle beam deflection according to claim 1, characterized in that, The coaxial feed probe (4) is located on the center line of the wide side of the main waveguide of the series feed power divider network (2).

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