Waveguide-microstrip conversion device for waveguide array antenna feed

Abstract

The waveguide-microstrip conversion device comprises a dielectric substrate, a first grounding layer and a second grounding layer are arranged on the upper surface and the lower surface of the dielectric substrate respectively, a rectangular waveguide is arranged on the first grounding layer, a window is formed in the narrow wall of one side of the rectangular waveguide, a metal patch is arranged in the first grounding layer, and the metal patch is arranged in the second grounding layer. The metal patch comprises an L-shaped short-circuit stub and a reconfigurable grounding metal gasket, the upper surface of the dielectric substrate is provided with a microstrip line, the microstrip line is connected with the L-shaped short-circuit stub through a window and feeds power to the L-shaped short-circuit stub, and the reconfigurable grounding metal gasket is connected with the second grounding layer; and double-ridge waveguide impedance transformer structures are arranged on the L-shaped short-circuit branch knots and the reconfigurable grounding metal gaskets. The ground structure at the tail end of the micro-strip transmission line is reconstructed to be combined with the double-ridge waveguide impedance transformer, good matching of an electric field and impedance is achieved at the same time, the working bandwidth is remarkably improved, the whole Ka working frequency band is covered, and the antenna has the advantages of being small in insertion loss and simple and compact in structure.

Description

Technical Field

[0001] The present invention relates to the field of radio, and in particular to a waveguide-microstrip conversion device for feeding a waveguide array antenna. Background Art

[0002] Rectangular waveguide structures based on narrow-side excitation often serve as the input for waveguide-excited antenna arrays and have broad application potential in phased array systems. However, when a waveguide is used as the output element of a phased array transmit channel, if a rectangular waveguide structure based on broad-side excitation is employed, the spacing between adjacent waveguides in a standard rectangular waveguide will be greater than the length of the rectangular waveguide's broadside, failing to meet the requirement that the array element spacing be less than half the operating wavelength of the transmitted signal. This results in an excessively large main beam diameter for active array antennas based on rectangular waveguides, increasing the antenna's radiation grating lobes.

[0003] The integration of passive waveguide components and active circuits plays a crucial role in system-level integration of millimeter-wave front-ends. Due to its simple processing and excellent transmission characteristics, microstrip lines are a key transmission line form within millimeter-wave planar active integrated circuits. Therefore, a high-performance microstrip-to-waveguide transition device is essential for integrating waveguide-based wireless transceiver array antennas with the active circuits of GaN MMIC chips. Microstrip-to-rectangular waveguide transition structures are categorized as linear or vertical transitions, depending on the direction of energy propagation from the microstrip line to the rectangular waveguide. In linear transitions, the microstrip line terminals must be embedded within the waveguide, which can easily create air gaps during device assembly. This air gap can lead to significant errors in the millimeter-wave band. In contrast, the vertical waveguide-to-microstrip transition method, based on excitation of the waveguide terminal end face, allows the waveguide flange end face to be directly mounted on the PCB. This offers the advantages of simple assembly, ease of multi-layer PCB integration, and the elimination of waveguide soldering.

[0004] End-fed waveguide-to-microstrip transition circuits can be divided into E-plane end-fed waveguide-to-microstrip transitions and H-plane end-fed waveguide-to-microstrip transitions, depending on the location of the microstrip line feeding into the waveguide. Compared to E-plane end-fed waveguide-to-microstrip transitions, H-plane end-fed waveguide-to-microstrip transitions introduce a microstrip line feed parallel to the H-plane of the rectangular waveguide from the narrow edge of the waveguide end wall. This allows for the close arrangement of multiple waveguide-fed array antenna elements, achieving an element channel spacing of less than 1 / 2 wavelength. This facilitates the linear layout of the array antenna and improves sidelobe performance indicators. It has a wide range of applications in active beam scanning antenna arrays and multiple-input multiple-output array antennas.

[0005] The existing end-fed waveguide-microstrip conversion circuit has the following defects:

[0006] 1. The H-plane end-fed waveguide-microstrip transition design is difficult, and the existing conversion device has a narrow operating bandwidth and cannot meet the application requirements of broadband information transmission;

[0007] 2. It requires a 1 / 4 wavelength waveguide back cavity, which is not easy to integrate with multi-layer PCB circuits, increasing the size of the transition structure and the difficulty of processing and manufacturing.

[0008] 3. The E-plane feeding structure is not compact and cannot meet the feeding requirements of multi-input waveguide arrays. Summary of the Invention

[0009] In order to solve the above technical problems, the present invention provides a waveguide-microstrip conversion device for feeding waveguide array antennas with a simple and compact structure and a wide operating frequency band.

[0010] The present invention provides a technical solution for solving the above-mentioned technical problems. The device comprises a waveguide-to-microstrip conversion device for feeding a waveguide array antenna, comprising a dielectric substrate, a microstrip line, a rectangular waveguide, a metal patch, and a double-ridged waveguide impedance converter structure. The dielectric substrate has a first ground layer on its upper surface and a second ground layer on its lower surface. A rectangular waveguide is disposed on the first ground layer, the rectangular waveguide being structurally orthogonal to the dielectric substrate. A window is provided in a narrow wall on one side of the rectangular waveguide. A metal patch is disposed within the first ground layer, the metal patch comprising an L-shaped short-circuit branch and a reconfigurable grounded metal pad symmetrically arranged relative to the X-axis. A microstrip line is disposed on the upper surface of the dielectric substrate along the X-axis. The microstrip line connects to the L-shaped short-circuit branch through the window in the narrow wall of the rectangular waveguide and feeds power to the L-shaped short-circuit branch. The reconfigurable grounded metal pad is connected to the second ground layer via a metallized via below. A double-ridged waveguide impedance converter structure is disposed on the L-shaped short-circuit branch and the reconfigurable grounded metal pad.

[0011] The above-mentioned waveguide-to-microstrip conversion device for feeding waveguide array antennas has a three-level double-ridged waveguide impedance converter, including a first double-ridged waveguide, a second double-ridged waveguide, and a third double-ridged waveguide stacked in sequence. By introducing the double-ridged waveguide impedance converter, broadband impedance matching is provided between the high characteristic impedance of the WR28 waveguide and the low characteristic impedance of the microstrip line, thereby extending the operating bandwidth of the waveguide-to-microstrip conversion device to the entire Ka band.

[0012] The above-mentioned waveguide-microstrip conversion device for feeding a waveguide array antenna, the cross section of the rectangular waveguide includes a wide side extending along the X-axis direction and a narrow side extending along the Y-axis direction.

[0013] In the above-mentioned waveguide-microstrip conversion device for feeding a waveguide array antenna, the L-shaped short-circuit branch is arranged at the center position of the wide side of one side of the rectangular waveguide, and the L-shaped short-circuit branch and the wide side of one side of the rectangular waveguide are perpendicular to each other in direction and structurally connected.

[0014] In the waveguide-microstrip conversion device for feeding a waveguide array antenna, the reconfigurable grounding metal gasket and the other wide side of the rectangular waveguide are perpendicular to each other in direction and structurally connected.

[0015] The above-mentioned waveguide-microstrip conversion device for feeding waveguide array antennas has periodically arranged metallized vias on the dielectric substrate, which are distributed around the lower edge of the rectangular waveguide and connect the first ground layer and the second ground layer.

[0016] In the waveguide-microstrip conversion device for feeding a waveguide array antenna, the rectangular waveguide adopts the size of the WR28 standard waveguide.

[0017] In the above-mentioned waveguide-microstrip conversion device for feeding waveguide array antennas, the dielectric substrate is made of RO5880 material with a thickness of 0.508 mm, a dielectric constant of 2.2, and a microstrip line impedance value of 50Ω.

[0018] In the waveguide-microstrip conversion device for feeding a waveguide array antenna, the widths of the first double-ridged waveguide, the second double-ridged waveguide, and the third double-ridged waveguide are consistent with the width of the L-shaped short-circuit branch. The cutoff frequency and characteristic impedance of the double-ridged waveband are determined by the spacing of the double-ridged waveguides. The cutoff frequency of the double-ridged waveguide is determined by the transverse resonance method, and the calculation formula is as follows:

[0019]

[0020] Where a is the length of the wide side of the rectangular waveguide, b is the length of the narrow side of the rectangular waveguide, g is the spacing of the double-ridge waveguide, and w is the length of the narrow side of the rectangular waveguide. d is the width of the double-ridge waveguide, f cr Is a rectangular waveguide in TE 10 Mode cutoff frequency, f cd represents the cutoff frequency of the double-ridge waveguide with the same rectangular waveguide dimensions in TE mode;

[0021] Characteristic impedance Z of double-ridge waveguide or The calculation formula is:

[0022]

[0023] Where f is the operating frequency, Z or (∞) is the characteristic impedance at infinite frequency, Z or The calculation formula for (∞) is:

[0024]

[0025] Where, γ is an intermediate variable, which is used to represent the correction factor of the ratio of the characteristic impedance of the double-ridge waveguide at different frequencies to the impedance at the high-frequency limit; α is also an intermediate variable, which represents another correction factor that needs to be considered when calculating the characteristic impedance of the double-ridge waveguide;

[0026] The third-order Chebyshev impedance matching method is used to calculate the characteristic impedances of the first double-ridged waveguide, the second double-ridged waveguide, and the third double-ridged waveguide. Finally, the initial dimensions of the first double-ridged waveguide, the second double-ridged waveguide, and the third double-ridged waveguide are determined by iterating the above five formulas.

[0027] In the waveguide-microstrip conversion device for feeding a waveguide array antenna, the length of the first double-ridged waveguide is consistent with the length of the metal patch.

[0028] The beneficial effects of the present invention are:

[0029] 1. This invention combines a reconstructed microstrip transmission line terminal structure with a double-ridged waveguide impedance converter to achieve simultaneous matching of electromagnetic fields and impedances, increasing the relative operating bandwidth to 41%. This overcomes the narrow bandwidth problem of traditional end-fed H-plane waveguide-to-microstrip vertical conversion structures and achieves full Ka-band coverage. The invented waveguide-to-microstrip conversion device uses a microstrip line parallel to the H-plane of a rectangular waveguide to feed power from the narrow edge of the waveguide end wall, ensuring that the channel spacing between waveguide arrays is less than 1 / 2 the operating wavelength. This device is suitable for direct connection to waveguide-fed active beam scanning antenna arrays and multiple-input, multiple-output antenna systems.

[0030] 2. The present invention uses bias feeding to adjust impedance matching between the microstrip line and the L-shaped short-circuit branch, without adding an additional impedance matching microstrip line, and has a simpler structure.

[0031] 3. The present invention uses an L-shaped short-circuit branch to replace the 1 / 4 wavelength waveguide back cavity structure. Compared with the traditional loaded waveguide back cavity and the transition structure feeding along the E-plane of the rectangular waveguide, it has the advantages of compact structure and easy integration with multi-layer PCB circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall structure of the waveguide-microstrip conversion device for feeding the waveguide array antenna of the present invention.

[0033] Figure 2 yes Figure 1 Schematic top view of .

[0034] Figure 3 It is a structural schematic diagram of the L-shaped short-circuit branch and the reconfigurable grounding metal gasket of the present invention.

[0035] Figure 4 yes Figure 2 Schematic side view of .

[0036] Figure 5 It is a schematic diagram of the electric field conversion process of the present invention.

[0037] Figure 6 yes Figure 5 EE cross-sectional view in.

[0038] Figure 7 yes Figure 5 FF cross-sectional view in.

[0039] Figure 8 It is a simulation result diagram of the present invention. DETAILED DESCRIPTION

[0040] The present invention will be further described below with reference to the accompanying drawings and examples.

[0041] like Figure 1-Figure 4 As shown, a waveguide-microstrip conversion device for feeding a waveguide array antenna includes a dielectric substrate 1, a microstrip line 100, a rectangular waveguide 200, a metal patch 4, and a double-ridged waveguide impedance transformer structure 5. The upper surface of the dielectric substrate 1 is provided with a first ground layer 31, and the lower surface of the dielectric substrate 1 is provided with a second ground layer 32. The rectangular waveguide 200 is provided on the first ground layer 31. The rectangular waveguide 200 is structurally orthogonal to the dielectric substrate 1. The top of the rectangular waveguide 200 is a waveguide port 8. The metal patch 4 is provided inside the first ground layer 31. The metal patch 4 includes L-shaped short-circuit branches symmetrically placed relative to the X-axis. 41 and a reconfigurable grounding metal gasket 42, a window 6 is opened on the narrow wall of one side of the rectangular waveguide 200, a microstrip line 100 is set on the upper surface of the dielectric substrate 1 along the X-axis direction, the microstrip line 100 penetrates the waveguide end wall through the window 6 on the narrow wall of the rectangular waveguide 200 to connect to the L-shaped short-circuit branch 41 and feeds power to the L-shaped short-circuit branch 41, the reconfigurable grounding metal gasket 42 is connected to the second ground layer 32 through the metallized via 11 below, the reconfigurable grounding metal gasket 42 can be extended along the negative direction of the X-axis to achieve good field matching; a double-ridged waveguide impedance transformer structure 5 is set on the L-shaped short-circuit branch 41 and the reconfigurable grounding metal gasket 42.

[0042] The double-ridged waveguide impedance converter structure 5 is a three-level structure, including a first double-ridged waveguide 51, a second double-ridged waveguide 52, and a third double-ridged waveguide 53 stacked in sequence. By introducing the double-ridged waveguide impedance converter 5, broadband impedance matching is provided between the high characteristic impedance of the WR28 waveguide and the low characteristic impedance of the microstrip line, thereby extending the operating bandwidth of the waveguide-microstrip conversion device to the entire Ka band.

[0043] The cross section of the rectangular waveguide 200 includes a wide side 201 extending along the X-axis direction and a narrow side 202 extending along the Y-axis direction.

[0044] The L-shaped shorting stub 41 is positioned at the center of one wide side 201 of the rectangular waveguide 200. The L-shaped shorting stub 41 and one wide side 201 of the rectangular waveguide 200 are perpendicular to each other and structurally connected. The reconfigurable grounding metal pad 42 is perpendicular to the other wide side 201 of the rectangular waveguide 200 and structurally connected. The L-shaped shorting stub 41 and the reconfigurable grounding metal pad 42 establish electrical contact between the double-ridged waveguide impedance transformer structure 5 and the microstrip line 100, improving field matching performance and enabling broadband transmission of electromagnetic wave signals.

[0045] Periodically arranged metallized vias 11 are provided on the dielectric substrate 1 to prevent energy leakage. The metallized vias 11 are distributed around the lower edge of the rectangular waveguide 200 to prevent or reduce leakage of electromagnetic waves. The metallized vias 11 connect the first ground layer 31 and the second ground layer 32.

[0046] The rectangular waveguide 200 adopts the WR28 standard waveguide. The dielectric substrate 1 is made of RO5880 material with a thickness of 0.508 mm and a dielectric constant of 2.2. The impedance of the microstrip line 100 is 50Ω.

[0047] Using electromagnetic simulation software, it is calculated that the width Wm of the 50Ω microstrip line 100 at a center frequency of 33 GHz is approximately 0.78 mm.

[0048] The biased microstrip line 100 is used to feed the L-shaped short-circuit branch 41. The impedance matching can be adjusted by changing the offset W_off of the feeding position of the microstrip line 100. The maximum value of the offset W_off shall not cause the left side of the microstrip line 100 to exceed the end of the L-shaped short-circuit branch 41. Figure 3 As shown, in this embodiment, W_off is 0.33 mm; the metal patch 4 includes an L-shaped short-circuit branch 41 and a reconfigurable grounding metal gasket 42, and the length Lp of the two is 1.54 mm, which is equal to the length L1 of the first double-ridge waveguide 51, and the width Wp of the L-shaped short-circuit branch 41 is 0.8 mm.

[0049] Reference Figure 3 Periodically arranged metallized vias 11 are provided in the dielectric substrate 1 ; the diameter of the metallized vias 11 is R=0.5 mm, and the period is P=0.7 mm.

[0050] Reference Figure 4Broadband impedance matching is achieved using the double-ridged waveguide impedance transformer structure 5. The widths of the first double-ridged waveguide 51, the second double-ridged waveguide 52, and the third double-ridged waveguide 53 are consistent with the width Wp of the L-shaped short-circuit stub 41. The length L1 of the first double-ridged waveguide 51 is consistent with the length Lp of the metal patch 4. The height h1 of the first double-ridged waveguide 51 is 1.25 mm. The length L2 of the second double-ridged waveguide 52 is 1.2 mm, and the height h2 of the second double-ridged waveguide 52 is 1.2 mm. The length L3 of the third double-ridged waveguide 53 is 0.48 mm, and the height h3 of the third double-ridged waveguide 53 is 1.44 mm. The spacing g1 of the first double-ridged waveguide 51 is 0.48 mm, the spacing g2 of the second double-ridged waveguide 52 is 1.16 mm, and the spacing g3 of the third double-ridged waveguide 53 is 2.6 mm.

[0051] The widths of the first double-ridged waveguide 51, the second double-ridged waveguide 52, and the third double-ridged waveguide 53 are consistent with the width Wp of the L-shaped short-circuit branch. The cutoff frequency and characteristic impedance of the double-ridged waveguide band are determined by the spacing of the double-ridged waveguides. The cutoff frequency of the double-ridged waveguide is determined by the transverse resonance method, and the calculation formula is as follows:

[0052]

[0053] Where a is the length of the wide side of the rectangular waveguide, b is the length of the narrow side of the rectangular waveguide, g is the spacing of the double-ridge waveguide, and w is the length of the narrow side of the rectangular waveguide. d is the width of the double-ridge waveguide, f cr Is a rectangular waveguide in TE 10 Mode cutoff frequency, f cd represents the cutoff frequency of the double-ridge waveguide with the same rectangular waveguide dimensions in TE mode;

[0054] Characteristic impedance Z of double-ridge waveguide or The calculation formula is:

[0055]

[0056] Where f is the operating frequency, which is relative to the cutoff frequency f of the double-ridge waveguide. cr For example, it is used to calculate the characteristic impedance of the waveguide at different frequencies, Z or (∞) is the characteristic impedance at infinite frequency, Z or The calculation formula for (∞) is:

[0057]

[0058]

[0059] Where γ is an intermediate variable that represents the correction factor for the ratio of the characteristic impedance of the double-ridge waveguide at different frequencies to the impedance at the high-frequency limit. α is also an intermediate variable that represents another correction factor that needs to be considered when calculating the characteristic impedance of the double-ridge waveguide.

[0060] The third-order Chebyshev impedance matching method is used to calculate the characteristic impedance of the first double-ridge waveguide to be 67Ω, the characteristic impedance of the second double-ridge waveguide to be 110Ω, and the characteristic impedance of the third double-ridge waveguide to be 198Ω. Finally, the initial dimensions of the first, second, and third double-ridge waveguides are determined by iterating the above five formulas.

[0061] The working principle of the present invention is as follows:

[0062] This embodiment is an end-fed H-plane waveguide-to-microstrip vertical transition structure. It utilizes an L-shaped short-circuit stub 41 and a reconfigurable ground metal pad 42 to rotate the electric field vector direction of the microstrip line 100 by 90 degrees, achieving electric field matching between the microstrip line 100 and the rectangular waveguide 200. A double-ridged waveguide impedance converter structure 5 is then used to achieve broadband impedance matching between the microstrip line 100 and the rectangular waveguide 200. Specifically, the antenna is fed through the microstrip port, and electromagnetic waves travel through the microstrip line 100 through a window 6 in the narrow waveguide wall to the L-shaped short-circuit stub 41. A double-ridged waveguide impedance converter structure 5 is designed between the microstrip line 100 and the rectangular waveguide 200 as a multi-stage impedance converter, providing a smoother impedance conversion from the microstrip line to a standard rectangular waveguide and broadening the operating bandwidth of the converter. The L-shaped short-circuit branch 41 can not only replace the 1 / 4λ waveguide back cavity to enhance the energy coupling between the microstrip line and the rectangular waveguide, but also serve as the contact pad of the double-ridge matching structure together with the designed reconfigurable grounding metal gasket 42, so that the electric field vector direction between the double ridges rotates 90° (from the y-axis direction to the z-axis direction), thereby realizing the field matching between the double-ridge waveguide and the microstrip line and the seamless integration of the PCB and the rectangular waveguide.

[0063] Reference Figure 5 This section shows the basic structure of the transition from the narrow side 202 of the rectangular waveguide 200 to the microstrip line 100. By using the double-ridge waveguide impedance transformer structure 5, by introducing the L-shaped short-circuit branch 41 and the reconfigurable ground metal pad 42, the electric field vector direction of the microstrip line 100 is rotated 90 degrees at the waveguide end wall, thus achieving the TEM mode to TE mode. 10 The reconfigurable ground metal pad 42 and the L-shaped short-circuit branch 41 act as an electrical contact pad between the microstrip line 100 and the double-ridge waveguide, ensuring effective electric field matching. In the transition structure based on narrow wall feeding, the current direction of the microstrip line 100 is consistent with the TE of the waveguide. 10The electric field vector direction at the end of the microstrip line 100 is rotated 90 degrees, thereby achieving efficient energy coupling between the microstrip line 100 and the rectangular waveguide 200.

[0064] Figure 6 and Figure 7 is based on Figure 5 , looking along the positive direction of the y-axis, the cross-sectional views of the EE and FF surfaces at two different positions, this part shows the distribution and conversion mechanism of the electric field (E-field) in the transition structure where the narrow side wall end connects the microstrip line 100 to the rectangular waveguide 200. Figure 6 and Figure 7 The paper describes how the proposed narrow wall transition design achieves electric field matching through the L-shaped short-circuit branch 41 and the reconfigurable ground metal pad 42, and promotes the electric field vector direction of the microstrip line 100 to rotate 90 degrees from the z-axis direction to the x-axis direction at the waveguide end wall, thereby realizing the TEM mode to TE mode. 10 Mode conversion.

[0065] The following is a further description of the technical effects of the present invention in combination with the design results:

[0066] 1. Simulation conditions and content

[0067] Reference Figure 8 , the three-dimensional electromagnetic simulation software is used to simulate, the center frequency of the simulation is set to 33GHz, and the return loss S of the conversion circuit structure is obtained. 11 , Insertion loss S 21 Distribution map.

[0068] 2. Simulation results analysis

[0069] Reference Figure 8 The horizontal axis represents frequency, and the vertical axis represents return loss or insertion loss. Taking the return loss less than -19dB as the standard, the bandwidth of this embodiment is 26.5-40GHz, and the relative bandwidth is 41%.

Claims

1. A waveguide-to-microstrip conversion device for feeding a waveguide array antenna, characterized in that: The invention comprises a dielectric substrate, a microstrip line, a rectangular waveguide, a metal patch, and a double-ridged waveguide impedance converter structure. A first ground layer is provided on the upper surface of the dielectric substrate, and a second ground layer is provided on the lower surface of the dielectric substrate. A rectangular waveguide is provided on the first ground layer, and the rectangular waveguide is structurally orthogonal to the dielectric substrate. A window is provided on a narrow wall on one side of the rectangular waveguide. A metal patch is provided inside the first ground layer, and the metal patch includes an L-shaped short-circuit branch and a reconfigurable grounding metal pad symmetrically placed relative to the X-axis. A microstrip line is provided on the upper surface of the dielectric substrate along the X-axis direction, and the microstrip line is connected to the L-shaped short-circuit branch through the window on the narrow wall of the rectangular waveguide and feeds power to the L-shaped short-circuit branch. The reconfigurable grounding metal pad is connected to the second ground layer through a metallized via below. A double-ridged waveguide impedance converter structure is provided on the L-shaped short-circuit branch and the reconfigurable grounding metal pad.

2. The waveguide-to-microstrip conversion device for feeding a waveguide array antenna according to claim 1, characterized in that: The double-ridged waveguide impedance converter has a three-level structure, including a first double-ridged waveguide, a second double-ridged waveguide, and a third double-ridged waveguide stacked in sequence. By introducing the double-ridged waveguide impedance converter, broadband impedance matching is provided between the high characteristic impedance of the WR28 waveguide and the low characteristic impedance of the microstrip line, thereby extending the operating bandwidth of the waveguide-microstrip conversion device to the entire Ka band.

3. The waveguide-to-microstrip conversion device for feeding a waveguide array antenna according to claim 1, wherein: The cross section of the rectangular waveguide includes a wide side extending along the X-axis direction and a narrow side extending along the Y-axis direction.

4. The waveguide-to-microstrip conversion device for feeding a waveguide array antenna according to claim 3, wherein: The L-shaped short-circuit branch is arranged at the center of the wide side of one side of the rectangular waveguide, and the L-shaped short-circuit branch and the wide side of one side of the rectangular waveguide are perpendicular to each other in direction and structurally connected.

5. The waveguide-to-microstrip conversion device for feeding a waveguide array antenna according to claim 3, wherein: The reconfigurable grounding metal gasket and the other wide side of the rectangular waveguide are perpendicular to each other in direction and structurally connected.

6. The waveguide-to-microstrip conversion device for feeding a waveguide array antenna according to claim 1, wherein: Periodically arranged metallized vias are provided on the dielectric substrate. The metallized vias are distributed around the lower edge of the rectangular waveguide, and the metallized vias are connected to the first ground layer and the second ground layer.

7. The waveguide-to-microstrip conversion device for feeding a waveguide array antenna according to claim 1, wherein: The size of the rectangular waveguide adopts the WR28 standard waveguide.

8. The waveguide-to-microstrip conversion device for feeding a waveguide array antenna according to claim 1, wherein: The dielectric substrate is made of RO5880 material with a thickness of 0.508 mm, a dielectric constant of 2.2, and a microstrip line impedance of 50Ω.

9. The waveguide-to-microstrip conversion device for feeding a waveguide array antenna according to claim 2, wherein: The widths of the first, second, and third double-ridged waveguides are consistent with the width of the L-shaped short-circuit branches. The cutoff frequency and characteristic impedance of the double-ridged waveguide band are determined by the spacing of the double-ridged waveguides. The cutoff frequency of the double-ridged waveguide is determined by the transverse resonance method, and the calculation formula is as follows: Where a is the length of the wide side of the rectangular waveguide, b is the length of the narrow side of the rectangular waveguide, g is the spacing of the double-ridge waveguide, and w is the length of the narrow side of the rectangular waveguide. d is the width of the double-ridge waveguide, f cr Is a rectangular waveguide in TE 10 Mode cutoff frequency, f cd represents the cutoff frequency of the double-ridge waveguide with the same rectangular waveguide dimensions in TE mode; Characteristic impedance Z of double-ridge waveguide or The calculation formula is: Where f is the operating frequency, Z or (∞) is the characteristic impedance at infinite frequency, Z or The calculation formula for (∞) is: Where, γ is an intermediate variable, which is used to represent the correction factor of the ratio of the characteristic impedance of the double-ridge waveguide at different frequencies to the impedance at the high-frequency limit; α is also an intermediate variable, which represents another correction factor that needs to be considered when calculating the characteristic impedance of the double-ridge waveguide; The third-order Chebyshev impedance matching method is used to calculate the characteristic impedances of the first double-ridged waveguide, the second double-ridged waveguide, and the third double-ridged waveguide. Finally, the initial dimensions of the first double-ridged waveguide, the second double-ridged waveguide, and the third double-ridged waveguide are determined by iterating the above five formulas.

10. The waveguide-microstrip conversion device for feeding a waveguide array antenna according to claim 2, characterized in that: The length of the first double-ridge waveguide is consistent with the length of the metal patch.

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