A multi-channel coupler for dual-polarized waveguide phased array antenna

Abstract

The present invention relates to the field of passive network technology. Specifically disclosed is a multi-channel coupler for dual-polarization waveguide phased array antennas, including a horizontally polarized waveguide antenna, a vertically polarized waveguide antenna, a horizontally polarized coupled waveguide, a vertically polarized coupled waveguide, and a coupling structure connected between the waveguide antenna and the coupled waveguide. The horizontally polarized coupled waveguide and the vertically polarized coupled waveguide respectively connect m horizontally polarized coupling units and n vertically polarized coupling units in series through the vertical polarization coupling structure and the horizontal polarization coupling structure to form an integrated structure including m+n coupling units; wherein the horizontally polarized waveguide antenna is connected to the horizontally polarized coupling structure to form a horizontally polarized coupling unit, and the vertically polarized waveguide antenna is connected to the vertically polarized coupling structure to form a vertically polarized coupling unit. The present invention solves the problems of poor directivity and low amplitude consistency of existing waveguide couplers, and improves the amplitude consistency and isolation of the multi-channel coupler.

Description

Technical Field

[0001] The present invention belongs to the technical field of passive networks, and in particular relates to a multi-channel coupler that can be used for detection and calibration of radio frequency channels at the rear end of a waveguide phased array antenna. Background Art

[0002] Waveguide phased array antennas achieve beam scanning without mechanical rotation by regulating the amplitude and phase of each antenna element. They feature low insertion loss, high sensitivity, fast scanning speed, and beamforming. Waveguide phased array antennas' sidelobe levels and beam pointing accuracy are significantly affected by the amplitude and phase of the RF channels, necessitating the installation of couplers. By testing the coupled amplitude and phase before and after adding RF components, each RF channel is compensated to ensure the performance of the phased array antenna. The performance of the multi-channel coupler, serving as the calibration network for the waveguide phased array antenna, directly impacts the radiation performance of the phased array antenna.

[0003] Couplers are currently widely used. For example, patent document CN202110404206.0 discloses a "multi-channel waveguide coupler for calibrating networks." This coupler achieves channel calibration of waveguide-type phased array antennas by setting a short transverse slot at the bottom of the horizontally polarized coupling channel and connecting the horizontally polarized waveguide underneath, setting a long transverse slot at the bottom of the vertically polarized coupling channel, setting a sunken structure on the lower side, and connecting the vertically polarized waveguide on the lower side. However, the isolation of this waveguide coupler is poor, the directivity is weak, and the amplitude and phase of the coupled signal are easily affected by port matching, resulting in poor consistency in the coupling amplitude of each channel, and ultimately reducing the radiation capability of the phased array antenna.

[0004] In order to improve the directivity of the coupler, multiple coupling slots can be set. For example, the patent document with application number CN201610429499.7 discloses a "multi-hole waveguide directional coupler" technical solution, which improves the directivity of the waveguide coupler by setting two coupling holes asymmetrically at the bottom of the narrow side of the coupling waveguide to form a coupling hole array. However, this waveguide coupler has certain requirements for the size of the narrow side of the coupling waveguide. When the narrow side size is small, the directivity of the waveguide coupler is poor, and it can only couple the amplitude and phase of a single channel. For dual-polarization phased array antenna arrays, the waveguide size needs to be miniaturized to improve the phased array beam scanning capability and the number of channels is large. Therefore, this solution cannot be used in dual-polarization waveguide phased arrays. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the present invention proposes a multi-channel coupler for dual-polarized waveguide phased array antennas, which solves the problems of poor directivity, low amplitude consistency and inability to be applied to dual-polarized waveguide phased array antennas in existing waveguide couplers.

[0006] Compared with traditional waveguide couplers, the waveguide coupler of this invention can reduce the impact of port matching on the coupling amplitude consistency of each channel, thereby improving the amplitude consistency and isolation of multi-channel couplers. It can also enhance the accuracy of amplitude and phase compensation, improve the radiation capability of phased array antennas, and meet the requirements of dual-polarized phased array antennas with small array spacing.

[0007] The technical solution adopted in the present invention is:

[0008] A multi-channel coupler for a dual-polarized waveguide phased array antenna includes a horizontally polarized waveguide antenna 1, a vertically polarized waveguide antenna 2, a horizontally polarized coupling waveguide 3, a vertically polarized coupling waveguide 4, and a coupling structure connected between the waveguide antenna and the coupling waveguide. The horizontally polarized coupling waveguide 3 and the vertically polarized coupling waveguide 4 are connected in series via a vertically polarized coupling structure 6 and a horizontally polarized coupling structure 5, respectively, to form an integrated structure including m+n coupling units. The horizontally polarized waveguide antenna 1 is connected to the horizontally polarized coupling structure 5 to form a horizontally polarized coupling unit, and the vertically polarized waveguide antenna 2 is connected to the vertically polarized coupling structure 6 to form a vertically polarized coupling unit. m and n are natural numbers greater than 1.

[0009] The horizontally polarized coupling structure 5 is composed of two double-layer oblique slots with the same inclination direction and the same inclination angle t along the central axis of the horizontally polarized waveguide, and a spacing of l1. The gap size difference of the double-layer oblique slots is w1, and the heights are h1 and h2 respectively, where h1 is the thickness of the upper wall of the horizontally polarized waveguide antenna 1, and h2 is the thickness of the lower wall of the horizontally polarized coupling waveguide 3.

[0010] The length lf1, width wf1 and spacing l1 of the two slots in the horizontal polarization coupling structure 5 are determined according to the coupling amount, and the slot tilt angle t and spacing l1 are determined according to the directivity. The spacing l1 plays a decisive role in both the coupling amount and the directivity.

[0011] In the multi-channel coupler, the vertical polarization coupling structure 6 is composed of two double-layer longitudinal slits with different offset directions along the central axis of the vertical polarization waveguide, the same offset length p, and a spacing of l2. The gap size difference of the double-layer longitudinal slits is w2, and the heights are h3 and h4 respectively, where h3 is the upper wall thickness of the vertical polarization waveguide antenna 2, and h4 is the lower wall thickness of the vertical polarization coupling waveguide 4.

[0012] The length lf2, width wf2, and spacing l2 of the two slots in the vertical polarization coupling structure 6 are determined according to the coupling amount, and the slot offset length p and spacing l2 are determined according to the directivity. The spacing l2 plays a decisive role in both the coupling amount and the directivity.

[0013] In the multi-channel coupler, the horizontally polarized waveguide antenna 1 and the vertically polarized waveguide antenna 2 are arranged alternately with a spacing of w, which is equal to the actual spacing between the two polarizations of the antenna.

[0014] One end of the coupled waveguide is a coupled port, and the other is an isolated port. One end of the waveguide antenna is an antenna port, and the other end is a radiating antenna. The two polarized waveguide antennas are placed in the same orientation, and the two polarized coupled waveguides are placed in the same orientation, with the waveguide antenna and the coupled waveguide placed in an orthogonal direction.

[0015] The coupler is connected to the signal radiation link at a position between the active component and the passive antenna.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects and advantages:

[0017] First, the multi-channel coupler of the present invention improves the amplitude consistency and isolation of the multi-channel coupler, reducing the impact of port matching on the coupling amplitude consistency of each channel, improving the accuracy of amplitude and phase compensation, and enhancing the radiation capability of the phased array antenna. By using dual oblique slots and dual longitudinal slots as the coupling structure of the coupler, the coupler achieves high isolation, strong directivity, minimal impact from port matching, and high coupling amplitude consistency. Simulation results show that the multi-channel coupler using the present invention achieves isolation greater than 64dB and amplitude consistency of each port less than 0.2dB.

[0018] Second, the present invention can be used for a multi-channel coupler of a dual-polarized waveguide phased array antenna. Since horizontal polarization uses double slanted slots as a coupling structure, the longitudinal coupling size is reduced, and the narrow side size of the horizontally polarized waveguide antenna 1 is reduced, which can meet the use requirements of small unit spacing with small spacing in the array direction of the dual-polarized phased array antenna.

[0019] Third, the present invention can be used for a multi-channel coupler of a dual-polarized waveguide phased array antenna. Since the coupling structure adopts a double-layer slot structure, the processing and assembly error tolerance can be reduced.

[0020] Fourth, the multi-channel coupler of the present invention can be used for calibrating the radio frequency channels of waveguide-type dual-polarized phased array antennas. Furthermore, depending on the actual number of radio frequency channels, multiple single-polarized or multi-polarized waveguide-type phased array antenna channels can be used for calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is an overall structural diagram of the multi-channel coupler of the present invention;

[0022] Figure 2 is a structural diagram of the coupling portion of the multi-channel coupler of the present invention;

[0023] Figure 3 is a top cross-sectional view of a multi-channel coupler of the present invention;

[0024] Figure 4 is a side perspective view of a multi-channel coupler of the present invention;

[0025] Figure 5 is the voltage standing wave ratio of the horizontally polarized coupled port 7 and the vertically polarized coupled port 8;

[0026] Figure 6 is the coupling degree from each horizontally polarized waveguide antenna port 9 to the horizontally polarized coupling port 7;

[0027] Figure 7 is the coupling degree from each vertically polarized antenna port 10 to the vertically polarized coupling port 8;

[0028] Figure 8 is the isolation from each horizontally polarized waveguide antenna port 9 to the horizontally polarized isolation port 12;

[0029] Figure 9 It is the isolation degree from each vertical polarization antenna port 10 to the vertical polarization isolation port 13. DETAILED DESCRIPTION

[0030] In order to make the technical concept and advantages of the invention more clearly understood, the technical solution of the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the following embodiments are only used to explain and illustrate the preferred embodiments of the present invention and should not be construed as limiting the scope of the patent protection claimed by the present invention.

[0031] Example 1

[0032] Reference Figure 1 The present invention is a multi-channel coupler for a dual-polarization waveguide phased array antenna, comprising a horizontally polarized waveguide antenna 1, a vertically polarized waveguide antenna 2, a horizontally polarized coupling waveguide 3, a vertically polarized coupling waveguide 4, and a coupling structure connected between the waveguide antenna and the coupling waveguide. The horizontally polarized waveguide antenna 1 is connected to the horizontally polarized coupling structure 5 to form a horizontally polarized coupling unit, and the vertically polarized waveguide antenna 2 is connected to the vertically polarized coupling structure 6 to form a vertically polarized coupling unit. The horizontally polarized coupling waveguide 3 and the vertically polarized coupling waveguide 4 are connected in series through the vertically polarized coupling structure 6 and the horizontally polarized coupling structure 5, respectively, to form an integrated structure including m+n coupling units. Wherein, m and n are natural numbers greater than 1.

[0033] The present invention is applicable to dual-polarized phased array antennas, i.e., phased array antennas composed of two mutually orthogonal polarization antennas. The horizontally polarized coupling port 7 and the vertically polarized coupling port 8 are connected to the same waveguide, the horizontally polarized isolation port 12 and the vertically polarized isolation port 13 are connected to the load, and the horizontally polarized waveguide antenna port 9 and the vertically polarized antenna port 10 are connected to the same waveguide.

[0034] Reference Figure 2 The present invention is a multi-channel coupler for a dual-polarized waveguide phased array antenna. The antenna through-port 11 is connected to a horizontally polarized narrow-side slanted slot antenna and a vertically polarized wide-side longitudinal slot antenna, respectively. The coupler is connected to a signal radiation link between an active component and a passive antenna. The coupling degree of each channel can be obtained by testing the S parameters from the coupling port to each antenna port.

[0035] Example 2

[0036] Reference Figure 3 The multi-channel coupler for the dual-polarized waveguide phased array antenna of this embodiment differs from that of Example 1 in that its horizontally polarized coupling structure 5 comprises two double-layer oblique slots having the same inclination direction and the same inclination angle t along the central axis of the horizontally polarized waveguide, with a spacing of l1, a slot length of lf1, a slot width of wf1, and a slot size difference of w1 between the double-layer oblique slots.

[0037] The vertical polarization coupling structure 6 is two double-layer longitudinal slots with different bias directions along the central axis of the vertical polarization waveguide, the same bias length p, and a spacing of l2. The slot length is lf2, the slot width is wf2, and the slot size difference of the double-layer longitudinal slot is w2.

[0038] This embodiment sets but is not limited to t=30°, l1=10.6mm, w1=0.2mm, p=2.2mm, l2=3.7mm, w2=0.2mm, lf1=7.5mm, wf1=1.4mm, lf2=13.2mm, wf2=1.4mm.

[0039] Reference Figure 4 The upper wall of the horizontally polarized waveguide antenna 1 fits tightly against the lower wall of the horizontally polarized coupling waveguide 3. The heights of the double-layer oblique slits are h1 and h2, respectively, where h1 is the thickness of the upper wall of the horizontally polarized waveguide antenna 1, and h2 is the thickness of the lower wall of the horizontally polarized coupling waveguide 3. The upper wall of the vertically polarized waveguide antenna 2 fits tightly against the lower wall of the vertically polarized coupling waveguide 4. The heights of the double-layer longitudinal slits are h3 and h4, respectively, where h3 is the thickness of the upper wall of the vertically polarized waveguide antenna 2, and h4 is the thickness of the lower wall of the vertically polarized coupling waveguide 4.

[0040] In this embodiment, it is set but not limited to h1 = 2 mm, h2 = 2 mm, h3 = 1 mm, and h4 = 9 mm.

[0041] The above-mentioned setting parameters are the dimensions simulated in the project, which are determined by the index requirements and the specific use environment.

[0042] The effects of the present invention can be further illustrated by simulation experiments based on the multi-channel coupler of this embodiment.

[0043] 1. Simulation conditions

[0044] Using High Frequency Structure Simulator simulation software Figure 2 The present invention is shown to be used for simulation of a multi-port coupler of a dual-polarization phased array antenna.

[0045] 2. Simulation content

[0046] Using High Frequency Structure Simulator simulation software Figure 2 The present invention is used to simulate the multi-port coupler of the dual-polarization phased array antenna. The horizontal polarization coupling port 7 standing wave and the vertical polarization port standing wave are obtained, as shown in FIG. Figure 5 As shown; the coupling degree of each horizontally polarized waveguide antenna port 9 to the horizontally polarized coupling port 7, as Figure 6 As shown; the coupling degree of each vertically polarized antenna port 10 to the vertically polarized coupling port 8, as Figure 7 As shown; the isolation degree of each horizontally polarized waveguide antenna port 9 to the horizontally polarized isolation port 12, as Figure 8 As shown; the isolation from the vertically polarized antenna port 10 to the vertically polarized isolation port 13 is as follows: Figure 9 shown; from Figure 5 It can be seen that within the working frequency band, the standing wave of the horizontal polarization coupling port 7 and the vertical polarization coupling port 8 of the coupler is less than 1.3, and the matching performance is excellent; Figure 6 It can be seen that within the working frequency band, the horizontal polarization coupling degree of the coupler is between -42.9dB and -43dB, and the coupling degree fluctuation is less than 0.06dB, which shows excellent coupling characteristics. Figure 7 It can be seen that within the working frequency band, the vertical polarization coupling degree of the coupler is between -44.3dB and -42.5dB, and the coupling degree fluctuation is less than 0.14dB, which shows excellent coupling characteristics. Figure 8 It can be seen that within the working frequency band, the horizontal polarization isolation of the coupler is greater than 67.3dB, which has high isolation characteristics. Figure 9 It can be seen that within the working frequency band, the vertical polarization isolation of the coupler is greater than 64.3dB, and has high isolation characteristics.

[0047] The simulation results demonstrate that this coupling structure provides a new solution for dual-polarization phased array antenna channel calibration. The coupler offers high coupling consistency, high isolation, strong directivity, and scalability, along with minimal coupling surface size requirements. Its double-layer slot structure provides a certain degree of tolerance, meeting the requirements for dual-polarization phased array RF channel calibration and enhancing the overall radiation capability of dual-polarization phased array antennas.

[0048] The above description is only a preferred embodiment of the present invention and should not constitute any limitation to the present invention. Those skilled in the art can conceive of making possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the content of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A multi-channel coupler for a dual-polarized waveguide phased array antenna, comprising a horizontally polarized waveguide antenna (1), a vertically polarized waveguide antenna (2), a horizontally polarized coupled waveguide (3), a vertically polarized coupled waveguide (4), and a coupling structure connected between the waveguide antenna and the coupled waveguide, characterized in that: The horizontal polarization coupling waveguide (3) and the vertical polarization coupling waveguide (4) are connected in series via a vertical polarization coupling structure (6) and a horizontal polarization coupling structure (5), respectively, to form an integrated structure including m+n coupling units; wherein the horizontal polarization waveguide antenna (1) is connected to the horizontal polarization coupling structure (5) to form a horizontal polarization coupling unit, and the vertical polarization waveguide antenna (2) is connected to the vertical polarization coupling structure (6) to form a vertical polarization coupling unit.

2. The multi-channel coupler according to claim 1, wherein: The horizontal polarization coupling structure (5) is composed of two double-layer oblique slots with the same inclination direction and the same inclination angle t along the central axis of the horizontal polarization waveguide, and a spacing of l1. The slot size difference of the double-layer oblique slots is w1, and the heights are h1 and h2 respectively, wherein h1 is the thickness of the upper wall of the horizontal polarization waveguide antenna (1), and h2 is the thickness of the lower wall of the horizontal polarization coupling waveguide (3).

3. The multi-channel coupler according to claim 2, wherein: The length lf1 and width wf1 of the two slots in the horizontal polarization coupling structure (5) are determined according to the coupling amount, the spacing (11) between the two slots is determined according to the coupling amount and the directivity, and the tilt angle t of the two slots is determined according to the directivity.

4. The multi-channel coupler according to claim 1, 2 or 3, wherein: The vertical polarization coupling structure (6) is composed of two double-layer longitudinal slits with different bias directions along the central axis of the vertical polarization waveguide, the same bias length p, and a spacing of l2. The gap size difference of the double-layer longitudinal slits is w2, and the heights are h3 and h4 respectively, where h3 is the thickness of the upper wall of the vertical polarization waveguide antenna (2), and h4 is the thickness of the lower wall of the vertical polarization coupling waveguide (4).

5. The multi-channel coupler according to claim 4, wherein: The length lf2 and width wf2 of the two slots in the vertical polarization coupling structure (6) are determined according to the coupling amount, the spacing l2 between the two slots is determined according to the coupling amount and the directivity, and the slot offset length p is determined according to the directivity.

6. The multi-channel coupler according to claim 1, 2, 3 or 5, wherein: The horizontally polarized waveguide antenna (1) and the vertically polarized waveguide antenna (2) are arranged in an alternating manner, with a spacing of w, which is equal to the actual spacing between the two polarizations of the antenna.

7. The multi-channel coupler according to claim 6, wherein: The two polarized waveguide antennas are placed in the same direction, the two polarized coupled waveguides are placed in the same direction, and the waveguide antenna and the coupled waveguide are placed in a direction orthogonal to each other; one end of the polarized waveguide antenna is an antenna port, and the other end is a radiating antenna; One end of the polarization coupling waveguide is a coupling port, and the other end is an isolation port.

8. The multi-channel coupler according to claim 2, 3 or 5, wherein: The coupling structure gaps are all rectangular holes, and arc chamfers are set at right angles; the outer contour size of the coupling structure gaps does not exceed the size of the coupling waveguide and the waveguide antenna cavity.

9. The multi-channel coupler according to claim 1, 2, 3, 5 or 7, wherein: The waveguide antenna is connected to the signal radiation link between the active component and the passive antenna.

10. The multi-channel coupler according to claim 1, 2, 3, 5 or 7, wherein: The waveguide of the horizontally polarized waveguide antenna (1) adopts a flat waveguide, and the waveguide of the vertically polarized waveguide antenna (2) adopts a ridge waveguide.

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