A substrate integrated waveguide monopulse slot antenna with a dual-mode comparator and a radiation method thereof

Abstract

The present invention discloses a substrate-integrated waveguide monopulse slot antenna with a dual-mode comparator and a radiation method thereof. The antenna comprises a first top metal layer, a 4N-channel radiation slot, a sum port, and a first difference port; a first dielectric substrate, a first substrate-integrated waveguide cavity comprising a first metal via, a second metal via, two 4N-channel power splitters, and a first dual-mode comparator; and a first coupling slot on the first metal bottom plate. A second top metal layer comprises a second coupling slot, a second difference port, and a third difference port; and a second dielectric substrate, a second substrate-integrated waveguide cavity comprising a third metal via, a fourth metal via, and a second dual-mode comparator. The first dual-mode comparator forms a sum beam and a difference beam on the xoz plane, respectively, while the second dual-mode comparator forms a difference beam and a dual difference beam on the yoz plane. The antenna of the present invention has the advantages of simplicity, compactness, high efficiency, low cost, and ease of integration, greatly simplifying the design of the monopulse antenna.

Description

Technical Field

[0001] The present invention relates to antenna technology, and in particular to a substrate-integrated waveguide single-pulse slot antenna with a dual-mode comparator and a radiation method thereof, which can be applied to X-band microwave target tracking, detection, radar communication and other purposes. Background Art

[0002] A monopulse antenna is an antenna that simultaneously transmits and receives signals from sum and difference channels. Due to its precise positioning and tracking capabilities, it is widely used in modern radar and satellite systems. Typically, a monopulse antenna consists of a monopulse network, which generates the sum and difference signals, and a radiating section, which radiates the signals.

[0003] Traditional monopulse antennas primarily utilize rectangular waveguides or monopulse feeders with reflective surfaces to achieve monopulse performance. However, such antennas are not only complex and bulky, but also have high manufacturing costs. In recent years, planar monopulse antennas such as microstrip arrays and substrate-integrated waveguide slot arrays have been widely used in radar tracking systems due to their small size, low cost, and ease of fabrication and integration. However, when feeding a microstrip line, the feeder will produce mutual coupling with the radiating portion, and its stray radiation will adversely affect the antenna pattern. A substrate-integrated waveguide, on the other hand, is a structure with waveguide-like properties. By etching metalized through-holes on a dielectric substrate with metal layers printed on the top and bottom, the through-holes are used to confine electromagnetic waves, avoiding the influence of the feed structure on the pattern. The waveguide has the advantages of a low profile, miniaturization, and low stray radiation.

[0004] Previous studies have proposed a variety of planar monopulse antenna arrays with excellent performance, such as high gain and low null depth. However, most designs suffer from complex feed networks, high antenna profiles, and poor port isolation. Summary of the Invention

[0005] Object of the invention: The object of the present invention is to provide a substrate integrated waveguide monopulse slot antenna with a dual-mode comparator and a radiation method thereof.

[0006] Technical solution: A substrate-integrated waveguide single-pulse slot antenna with a dual-mode comparator of the present invention comprises, from top to bottom, a first top metal layer, a first dielectric substrate, a first metal bottom plate, a second top metal layer, a second dielectric substrate, and a second metal bottom plate. The first top metal layer is provided with a 4N-path radiation slot, a sum port, and a first difference port. The first dielectric substrate is provided with a first substrate-integrated waveguide cavity. The first substrate-integrated waveguide cavity comprises a first metal via, a second metal via, a first 4N-path power divider, a second 4N-path power divider, and a first dual-mode comparator. Two first coupling slots are provided on the first metal bottom plate. A second coupling slot matching the first coupling slot, a second difference port, and a third difference port are provided on the second top metal layer. The second dielectric substrate is provided with a second substrate-integrated waveguide cavity. It includes a third metal via, a fourth metal via and a second dual-mode comparator; the first metal via and the third metal via respectively constitute the waveguide walls of the first substrate integrated waveguide cavity and the second substrate integrated waveguide cavity, and the second metal via and the fourth metal via are respectively used to perform impedance matching on the first substrate integrated waveguide cavity and the second substrate integrated waveguide cavity; the sum port and the first difference port respectively transmit the electromagnetic waves to the first dual-mode comparator, the first 4N-way power divider, the second 4N-way power divider, and the 4N-way radiation slot in sequence to form a sum beam and a difference beam electromagnetic wave on the xoz plane; the second difference port and the third difference port respectively transmit the electromagnetic waves to the second dual-mode comparator, the second coupling slot, the first coupling slot, the first 4N-way power divider, the second 4N-way power divider, and the 4N-way radiation slot in sequence to form a difference beam and a double difference beam on the yoz plane.

[0007] Preferably, the 4N-way radiation slot is divided into 4N radiation slot units, and the radiation slots in the same row in each radiation slot unit are staggered up and down on the transverse center line of the substrate integrated waveguide cavity. The sum port is excited, and the first dual-mode comparator generates the TE12 mode. After the electromagnetic wave passes through the first 4N-way power divider and the second 4N-way power divider, the first to 4N radiation slot units are in the same phase to form a sum beam; the first difference port is excited, and the first dual-mode comparator generates the TE21 mode. After the electromagnetic wave passes through the first 4N-way power divider and the second 4N-way power divider, the left 2N 2 The radiation gap unit and the right 2N 2 The phases of the two radiation units are opposite, forming a difference beam on the xoz plane; the second differential port is stimulated, and the second dual-mode comparator generates the TE12 mode. After the electromagnetic wave passes through the second coupling slot, the first coupling slot, the first 4N-way power divider and the second 4N-way power divider, the upper 2N 2 radiation gap unit and the next 2N 2The phases of the radiation slot units are opposite to form a difference beam on the yoz plane; when the third difference port is excited, the second dual-mode comparator generates the TE21 mode. After the electromagnetic wave passes through the second coupling slot, the first coupling slot, the first 4N-way power divider, and the second 4N-way power divider, the N 2 radiation slot units on the two diagonal lines have opposite phases to form a double difference beam.

[0008] Preferably, the radiation slots are etched on the first top metal layer. In the same radiation slot unit, the distance intervals of adjacent radiation slots in the same row on the x-axis are the same, with a value range of 13.5 mm to 15 mm; the height differences of adjacent radiation slots in the same row on the y-axis are the same, with a value range of 0.3 mm to 0.9 mm.

[0009] Preferably, the first 4N-way power divider and the second 4N-way power divider have the same structure, and are both composed of first metal vias arranged according to the function of the 4N-way power divider;

[0010] The first dual-mode comparator is composed of first metal vias arranged, and its outputs are respectively connected to the first 4N-way power divider and the second 4N-way power divider.

[0011] Preferably, the second dual-mode comparator is composed of third metal vias arranged, and its outputs are respectively connected to two second coupling slots, and the second coupling slots couple the electromagnetic wave to the first coupling slot.

[0012] Preferably, the first metal vias and the third metal vias are the same, and the range relationship between the diameter R and the distance d between two adjacent first metal vias or third metal vias is: R < d < 2R, 0.05 < d / center frequency wavelength < 0.25; the second metal vias and the fourth metal vias are the same, and their aperture ranges are: 0.7 mm - 0.9 mm. <​​​​​​​​​The sum port is stimulated, and the first dual-mode comparator generates a TE12 mode. The electromagnetic wave passes through the first 4N-way power divider and the second 4N-way power divider respectively, and is converted into 4N-way electromagnetic waves, which are respectively input into the 4N-way radiation slots, so that the first to 4N radiation slot units have the same phase, forming a sum beam;

[0017] Stimulate the first differential port, the first dual-mode comparator generates TE21 mode, and the electromagnetic wave passes through the first 4N-way power divider and the second 4N-way power divider respectively, and is converted into 4N-way electromagnetic waves and input into the 4N-way radiation slots respectively, so that the left 2N 2 The radiation gap unit and the right 2N 2 The phases of the radiating elements are opposite, forming a difference beam on the xoz plane;

[0018] The second differential port is stimulated, and the second dual-mode comparator generates TE12 mode. The electromagnetic waves pass through two sets of coupling slots, and then pass through the first 4N-way power divider and the second 4N-way power divider respectively, and are converted into 4N-way electromagnetic waves and input into 4N-way radiation slots respectively, so that the upper 2N 2 radiation gap unit and the next 2N 2 The phases of the radiation slot units are opposite, forming a difference beam on the yoz plane;

[0019] The third differential port is stimulated, and the second dual-mode comparator generates TE21 mode. The electromagnetic waves pass through two sets of coupling gaps, and then pass through the first 4N-way power divider and the second 4N-way power divider respectively, so that the N 2 The phases of the radiation slot units are opposite to each other, forming a double difference beam.

[0020] Beneficial Effects: Compared with existing technologies, the antenna of this invention simplifies its feeding scheme and utilizes two dual-mode comparators to generate a stable sum beam, difference beams on the xoz and yoz planes, and a dual-difference beam. While maintaining high radiation efficiency and a low profile, the antenna of this invention also offers advantages such as high isolation, ease of integration, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the antenna structure of the present invention, wherein (a) is a front view and (b) is a side view;

[0022] Figure 2 Schematic diagram of the top and bottom structures of the antenna of the present invention, wherein (a) is the top main view and (b) is the bottom main view;

[0023] Figure 3 The S-parameter diagram of the antenna of the present invention, where (a) is the reflection coefficient and (b) is the isolation;

[0024] Figure 43D radiation pattern of the antenna of the present invention, where (a) is the sum beam, (b) is the difference beam on the xoz plane, (c) is the difference beam on the yoz plane, and (d) is the double difference beam;

[0025] Figure 5 The directional diagram of the antenna of the present invention, where (a) is the sum beam, b) is the difference beam on the xoz plane, (c) is the difference beam on the yoz plane, (d) is the double difference beam on the +45° slant plane, and (e) is the double difference beam on the -45° slant plane. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] A substrate-integrated waveguide single-pulse slot antenna with a dual-mode comparator according to the present invention comprises, from top to bottom, a first top metal layer, a first dielectric substrate, a first metal bottom plate, a second top metal layer, a second dielectric substrate, and a second metal bottom plate. The first top metal layer is provided with a 4N-path radiation slot, a sum port, and a first difference port. The first dielectric substrate is provided with a first substrate-integrated waveguide cavity. The first substrate-integrated waveguide cavity comprises a first metal via, a second metal via, a first 4N-path power divider, a second 4N-path power divider, and a first dual-mode comparator. Two first coupling slots are provided on the first metal bottom plate. A second coupling slot matching the first coupling slot, a second difference port, and a third difference port are provided on the second top metal layer. The second dielectric substrate is provided with a second substrate-integrated waveguide cavity. The second substrate-integrated waveguide cavity comprises a third metal via, a fourth metal via, a first 4N-path power divider, a second 4N-path power divider, and a first dual-mode comparator. hole and the second dual-mode comparator; the 4N-way radiation slot is divided into 4N radiation slot units, and the radiation slots in the same row in each radiation slot unit are staggered up and down on the transverse center line of the substrate integrated waveguide cavity; the first metal via and the third metal via constitute the waveguide wall of the first substrate integrated waveguide cavity and the second substrate integrated waveguide cavity respectively; the second metal via and the fourth metal via are used to perform impedance matching on the first substrate integrated waveguide cavity and the second substrate integrated waveguide cavity respectively; the sum port is stimulated, the first dual-mode comparator generates the TE12 mode, and after the electromagnetic wave passes through the first 4N-way power divider and the second 4N-way power divider, the first to 4N radiation slot units are in phase, forming a sum beam; the first difference port is stimulated, the first dual-mode comparator generates the TE21 mode, and after the electromagnetic wave passes through the first 4N-way power divider and the second 4N-way power divider, the left 2N 2 The phase of the radiation slot unit is the same as the 2N on the right. 2 The phases of the two radiating units are opposite, forming a difference beam on the xoz plane; the second differential port is stimulated, and the second dual-mode comparator generates the TE12 mode. After the electromagnetic wave passes through the second coupling slot, the first coupling slot, the first 4N-way power divider and the second 4N-way power divider, the upper 2N 2 The phase sum of the radiation slot unit is 2N 2The phases of the radiation slot units are opposite, forming a difference beam on the yoz surface; the third difference port is stimulated, and the second dual-mode comparator generates the TE21 mode. After the electromagnetic wave passes through the second coupling slot, the first coupling slot, the first 4N-way power divider and the second 4N-way power divider, the N beams on the two diagonal lines are 2 The phases of the radiation slot units are opposite to each other, forming a double difference beam.

[0028] The power splitter of the embodiment of the present invention adopts a four-way power splitter, and the corresponding radiation analysis is four-way radiation slots, which are divided into four radiation slot units, as follows:

[0029] like Figure 1 and Figure 2 As shown, a substrate-integrated waveguide monopulse slot antenna with a dual-mode comparator comprises, from top to bottom, a first top metal layer 1, a first dielectric substrate 2, a first metal bottom plate 3, a second top metal layer 4, a second dielectric substrate 5, and a second metal bottom plate 6. The first top metal layer 1 is provided with four radiating slots, a sum port 11, and a first difference port 12. The four radiating slots are divided into a first radiating slot unit 13, a second radiating slot unit 14, a third radiating slot unit 15, and a fourth radiating slot unit 16. A first substrate-integrated waveguide cavity is provided on the first dielectric substrate 2. The first substrate-integrated waveguide cavity includes a first metal via 21, a second metal via 22, a first four-way power divider 23, a second four-way power divider 24, and a first dual-mode comparator 25. A first coupling slot 31 is provided on the first metal bottom plate 3. The second top metal layer 4 is provided with a second coupling slot 41 matching the first coupling slot, a second difference port 42 and a third difference port 43. The second dielectric substrate 5 is provided with a second substrate integrated waveguide cavity, which includes a third metal via 51, a fourth metal via 52 and a second dual-mode comparator 53. The first metal via 21 and the third metal via 51 respectively constitute the waveguide walls of the first substrate integrated waveguide cavity and the second substrate integrated waveguide cavity, which are used to bind electromagnetic waves and transmit them; the second metal via 22 and the fourth metal via 52 are respectively used to perform impedance matching on the first substrate integrated waveguide cavity and the second substrate integrated waveguide cavity, which are equivalent to inductors, and adjust the electric field distribution within the substrate integrated waveguide cavity to optimize the impedance bandwidth of the antenna; the first four-way power divider 23 and the second four-way power divider 24 have the same structure, both consisting of the first metal via 21 and the second metal via 22 arranged according to the function of the four-way power divider, and are used to feed one electromagnetic wave to four radiation slots on average; the first dual-mode comparator 25 is composed of the first metal via 21; the second dual-mode comparator 53 is composed of the third metal via 51; the two mutually orthogonal electromagnetic wave transmission modes in the dual-mode comparator greatly improve the isolation between the two ports; the non-metallic via 7 is used to fix the two plates.

[0030] When the antenna is operating, the excitation is applied to port 11, and the first dual-mode comparator 25 generates the TE12 mode. After the electromagnetic wave passes through the first four-way power divider 23 and the second four-way power divider 24, the phases of the first radiation slot unit 13, the second radiation slot unit 14, the third radiation slot unit 15, and the fourth radiation slot unit 16 are the same, forming a sum beam. When the first differential port 12 is excited, the first dual-mode comparator 25 generates the TE21 mode. After the electromagnetic wave passes through the first four-way power divider 23 and the second four-way power divider 24, the phases of the first radiation slot unit 13 and the third radiation slot unit 15 are opposite to the phases of the second radiation slot unit 14 and the fourth radiation slot unit 16, forming a difference beam on the xoz plane. When the second differential port 42 is excited, the second dual-mode comparator 53 generates the TE12 mode. After the electromagnetic wave passes through the second coupling slot 41, the first coupling slot 31, the first four-way power divider 23, and the second four-way power divider 24, the phases of the first radiation slot unit 13 and the second radiation slot unit 14 are opposite to the phases of the third radiation slot unit 15 and the fourth radiation slot unit 16, forming a difference beam on the yoz plane. When the third differential port 43 is excited, the second dual-mode comparator 53 generates the TE21 mode. After the electromagnetic wave passes through the second coupling slot 41, the first coupling slot 31, the first four-way power divider 23, and the second four-way power divider 24, the phases of the first radiation slot unit 13 and the fourth radiation slot unit 16 are opposite to the phases of the second radiation slot unit 14 and the third radiation slot unit 15, forming a double-difference beam.

[0031] In this embodiment, the four radiation slot units are etched on the first top metal layer 1. Each radiation slot unit includes 4 radiation slots, divided into 2 rows and 2 columns. The radiation slots in the same row within the same radiation slot unit are distributed with a vertical offset above and below the horizontal center line of the substrate integrated waveguide cavity. The distance intervals between adjacent radiation slots in the same row within the radiation slot unit on the x-axis are the same, with a value range of 13.5 mm to 15 mm; the height differences between adjacent radiation slots in the same row on the y-axis are the same, with a value range of 0.3 mm to 0.9 mm. In this embodiment, the distance between adjacent radiation slots in the same row on the x-axis is 13.58 mm, and the height difference on the y-axis is 0.6 mm.

[0032] The first metal via 21 and the third metal via 51 have the same structure. The range relationship between the diameter R and the distance d between two adjacent first metal vias 21 or third metal vias 51 is: R < d < 2R, 0.05 < d / center frequency wavelength < 0.25; the second metal via 22 and the fourth metal via 52 have the same structure, and their aperture ranges are: 0.7 mm - 0.9 mm.

[0033] The first dielectric substrate 2 and the second dielectric substrate 5 are made of Rogers 4003C material with a relative dielectric constant of 3.55 and a loss tangent of 0.0027, and a thickness of 1.524 mm; the first top metal layer 1, the second top metal layer 4 and the first metal bottom plate 3 and the second metal bottom plate 6 are all made of copper with a thickness of 0.035 mm.

[0034] The radiation method of the substrate integrated waveguide monopulse slot antenna with a dual-mode comparator is as follows:

[0035] The sum port 11 is stimulated, and the first dual-mode comparator 25 generates the TE12 mode. After the electromagnetic waves pass through the first four-way power divider 23 and the second four-way power divider 24, they are converted into four electromagnetic waves and input into the four radiation slots respectively, so that the first radiation slot unit 13, the second radiation slot unit 14, the third radiation slot unit 15 and the fourth radiation slot unit 16 have the same phase, forming a sum beam;

[0036] The first differential port 12 is stimulated, and the first dual-mode comparator 25 generates a TE21 mode. After the electromagnetic wave passes through the first four-way power divider 23 and the second four-way power divider 24, it is converted into four electromagnetic waves and input into the four radiation slots respectively. This makes the phases of the first radiation slot unit 13 and the third radiation slot unit 15 opposite to the phases of the second radiation slot unit 14 and the fourth radiation slot unit 16, forming a difference beam on the xoz plane;

[0037] The second differential port 42 is stimulated, and the second dual-mode comparator 53 generates a TE12 mode. The electromagnetic wave passes through the second coupling slot 41 and the first coupling slot 31 in sequence, and then passes through the first four-way power divider 23 and the second four-way power divider 24 respectively, and is converted into four electromagnetic waves and input into the four radiating slots respectively, so that the phase of the first radiating slot unit 13 and the second radiating slot unit 14 is opposite to the phase of the third radiating slot unit 15 and the fourth radiating slot unit 16, forming a difference beam on the yoz plane;

[0038] The third difference port 43 is stimulated, and the second dual-mode comparator 53 generates the TE21 mode. The electromagnetic wave passes through the second coupling slot 41 and the first coupling slot 31 in sequence, and then passes through the first four-way power divider 23 and the second four-way power divider 24 respectively, and is converted into four electromagnetic waves and input into the four radiation slots respectively, so that the phases of the first radiation slot unit 13 and the fourth radiation slot unit 16 are opposite to the phases of the second radiation slot unit 14 and the third radiation slot unit 15, forming a double difference beam.

[0039] Figure 3 Figure 2 is the S parameter curve of the antenna and difference beam of the present invention. It can be seen that the operating frequency band of the four ports of the antenna of the present invention is consistent, belonging to the X band, and the isolation of the ports is higher than 30dB.

[0040] Figure 4 FIG. 3 is the 3D radiation pattern of the antenna of the present invention. It can be seen that it has a stable sum beam, a difference beam in the xoz plane, a difference beam in the yoz plane, and a double difference beam.

[0041] Figure 5 (a) is the sum beam pattern of the antenna of the present invention, and the beam axial gain reaches up to 16dB, achieving high gain.

[0042] Figure 5 (b) and (c) are the difference beam patterns of the xoz plane and yoz plane of the antenna of the present invention, respectively. The zero depth is lower than -35dB, and the tracking error is extremely low.

[0043] Figure 5 (d) and (e) are the double-difference beam patterns of the antenna of the present invention at +45° and -45° slant planes, respectively, with a zero depth lower than 30 dB and a cross-polarization level lower than -30 dB.

[0044] The present invention relates to a substrate-integrated waveguide single-pulse slot antenna with a dual-mode comparator, which belongs to the field of antenna technology. This new substrate-integrated waveguide single-pulse slot antenna with a dual-mode comparator utilizes two mutually orthogonal electromagnetic wave transmission modes in the dual-mode comparator, greatly improving the isolation between the two ports, and the dual-feed design greatly improves the integration of the antenna and reduces manufacturing costs. At the same time, the coupling slot is used to replace the redundant feeding network, maintaining the high radiation efficiency of the antenna and realizing tracking and detection on two planes. The single-pulse antenna of the present invention has the advantages of high gain, low zero depth, high radiation efficiency, etc. while maintaining high isolation, which greatly simplifies the design of the single-pulse antenna feeding network.

Claims

1. A substrate integrated waveguide monopulse slot antenna with a dual-mode comparator, characterized in that: From top to bottom, it successively includes a first top metal layer, a first dielectric substrate, a first metal bottom plate, a second top metal layer, a second dielectric substrate and a second metal bottom plate. On the first top metal layer, there are 4N radiation slots, a sum port and a first difference port. On the first dielectric substrate, there is a first substrate integrated waveguide cavity, which includes first metal vias, second metal vias, a first 4N-way power divider, a second 4N-way power divider and a first dual-mode comparator. On the first metal bottom plate, there are two first coupling slots; on the second top metal layer, there is a second coupling slot matching the first coupling slot, a second difference port and a third difference port. On the second dielectric substrate, there is a second substrate integrated waveguide cavity, which includes third metal vias, fourth metal vias and a second dual-mode comparator; the first metal vias and the third metal vias respectively form the waveguide walls of the first substrate integrated waveguide cavity and the second substrate integrated waveguide cavity, and the second metal vias and the fourth metal vias are respectively used for impedance matching of the first substrate integrated waveguide cavity and the second substrate integrated waveguide cavity; the sum port and the first difference port respectively transmit electromagnetic waves to the first dual-mode comparator, the first 4N-way power divider, the second 4N-way power divider, and the 4N radiation slots in sequence, and then form a sum beam and a difference beam electromagnetic wave on the xoz plane; The second difference port and the third difference port respectively transmit electromagnetic waves to the second dual-mode comparator, the second coupling slot, the first coupling slot, the first 4N-way power divider, the second 4N-way power divider, and the 4N radiation slots in sequence, and then form a difference beam and a double difference beam on the yoz plane.

2. The substrate integrated waveguide monopulse slot antenna with a dual-mode comparator according to claim 1, characterized in that: The 4N radiation slots are divided into 4N radiation slot units. The radiation slots in the same row within each radiation slot unit are staggered up and down with respect to the horizontal center line of the substrate integrated waveguide cavity body. When the sum port is excited, the first dual-mode comparator generates a TE12 mode. After the electromagnetic waves pass through the first 4N-way power divider and the second 4N-way power divider, the phases of the first to the 4Nth radiation slot units are the same, forming a sum beam; Stimulate the first differential port, the first dual-mode comparator generates TE21 mode, the electromagnetic wave passes through the first 4N-way power splitter and the second 4N-way power splitter, making the left 2N 2 The radiation slot unit and the right 2N 2 The phases of the two radiation units are opposite, forming a difference beam on the xoz plane; the second differential port is stimulated, and the second dual-mode comparator generates the TE12 mode. After the electromagnetic wave passes through the second coupling slot, the first coupling slot, the first 4N-way power divider and the second 4N-way power divider, the upper 2N 2 radiation gap unit and the next 2N 2 The phases of the radiation slot units are opposite, forming a difference beam on the yoz plane; The third differential port is stimulated, and the second dual-mode comparator generates TE21 mode. After the electromagnetic wave passes through the second coupling slot, the first coupling slot, the first 4N-way power divider and the second 4N-way power divider, the N on the two diagonal lines are 2 The phases of the radiation slot units are opposite to each other, forming a double difference beam.

3. The substrate integrated waveguide monopulse slot antenna with a dual-mode comparator according to claim 2, characterized in that: The radiation slots are etched on the first top metal layer. In the same radiation slot unit, the distance intervals between adjacent radiation slots in the same row on the x-axis are the same, and the value range is 13.5 mm to 15 mm; the height differences between adjacent radiation slots in the same row on the y-axis are the same, and the value range is 0.3 mm to 0.9 mm.

4. The substrate integrated waveguide monopulse slot antenna with a dual-mode comparator according to claim 1, characterized in that: The first 4N-way power divider and the second 4N-way power divider have the same structure, and are both composed of first metal vias arranged according to the function of the 4N-way power divider; The first dual-mode comparator is composed of first metal vias arranged, and its outputs are respectively connected to the first 4N-way power divider and the second 4N-way power divider.

5. The substrate integrated waveguide monopulse slot antenna with a dual-mode comparator according to claim 1, characterized in that: The second dual-mode comparator is composed of third metal vias arranged, and its outputs are respectively connected to two second coupling slots, and the second coupling slots couple electromagnetic waves to the first coupling slot.

6. The substrate integrated waveguide monopulse slot antenna with a dual-mode comparator according to claim 1, characterized in that: The first metal vias and the third metal vias are the same, and the range relationship between their diameter R and the distance d between two adjacent first metal vias or third metal vias is: R < d < 2R, 0.05 < d / center frequency wavelength < 0.

7. The substrate integrated waveguide monopulse slot antenna with a dual-mode comparator according to claim 1, characterized in that: The first dielectric substrate and the second dielectric substrate are both made of Rogers 4003C material with a relative dielectric constant of 3.55 and a loss tangent of 0.0027, and a thickness of 1.524 mm.

8. The substrate integrated waveguide monopulse slot antenna with a dual-mode comparator according to claim 1, characterized in that: The first and second top metal layers and the first and second metal bottom plates are made of copper with a thickness of 0.035 mm.

9. A radiation method of a substrate integrated waveguide monopulse slot antenna with a dual-mode comparator, characterized in that: The antenna includes a sum port, three difference ports, two dual-mode comparators, two 4N-way power dividers, 4N-way radiation slots and two groups of coupling slots. The 4N-way radiation slots are divided into 4N radiation slot units. The radiation method includes the following steps: The sum port is stimulated, and the first dual-mode comparator generates a TE12 mode. The electromagnetic wave passes through the first 4N-way power divider and the second 4N-way power divider respectively, and is converted into 4N-way electromagnetic waves, which are respectively input into the 4N-way radiation slots, so that the first to 4N radiation slot units have the same phase, forming a sum beam; Stimulate the first differential port, the first dual-mode comparator generates TE21 mode, and the electromagnetic wave passes through the first 4N-way power divider and the second 4N-way power divider respectively, and is converted into 4N-way electromagnetic waves and input into the 4N-way radiation slots respectively, so that the left 2N 2 The radiation slot unit and the right 2N 2 The phases of the radiating elements are opposite, forming a difference beam on the xoz plane; The second differential port is stimulated, and the second dual-mode comparator generates TE12 mode. The electromagnetic waves pass through two sets of coupling slots, and then pass through the first 4N-way power divider and the second 4N-way power divider respectively, and are converted into 4N-way electromagnetic waves and input into 4N-way radiation slots respectively, so that the upper 2N 2 radiation gap unit and the next 2N 2 The phases of the radiation slot units are opposite, forming a difference beam on the yoz plane; The third differential port is stimulated, and the second dual-mode comparator generates TE21 mode. The electromagnetic waves pass through two sets of coupling gaps, and then pass through the first 4N-way power divider and the second 4N-way power divider respectively, so that the N 2 The phases of the radiation slot units are opposite to each other, forming a double difference beam.

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