A Line Source Based on Parallel Plate Waveguide Reflector Array

Abstract

This invention discloses a reflective surface array line source based on parallel plate waveguides, comprising a first parallel plate waveguide and a second parallel plate waveguide stacked sequentially, coupled with a corresponding waveguide power divider feed network. The first and second parallel plate waveguides are connected via a reflective surface array bend. The input port of the first parallel plate waveguide is connected to an H-plane horn array, and the input port of the H-plane array horn is connected to the output port of the waveguide power divider feed network. The output port of the second parallel plate waveguide is connected to a straight bend. This line source has a broadband structure, which can effectively reduce the longitudinal size of the line source while increasing the lateral output range. It produces a plane wave with uniform phase distribution and a "flat-top" amplitude distribution on a one-dimensional plane, thereby effectively reducing the size and manufacturing difficulty of large-aperture array antennas.

Description

Technical Field

[0001] This invention relates to the field of antenna feed technology, and in particular to a reflective surface array line source based on a parallel plate waveguide. Background Technology

[0002] Due to their excellent performance, array antennas are widely used in radar, communications, telemetry, and space technology. With the continuous advancement of communication systems, modern communication systems urgently require low-cost, miniaturized, high-gain, high-efficiency, and wide-bandwidth array antennas. Traditional array antennas include microstrip array antennas, parabolic antennas, and lens antennas.

[0003] A waveguide is a common low-loss transmission line and an important waveguide device for transmitting electromagnetic waves using a metal tube. Its walls are typically made of copper, aluminum, or other metals, and it is characterized by its simple structure and high mechanical strength. There is no internal conductor within the waveguide; electromagnetic energy is guided and propagated within the waveguide's internal space, preventing electromagnetic wave leakage. In antenna and line source design, waveguides are highly practical due to their low loss and high power capacity. Unfolding a one-dimensional waveguide structure into a two-dimensional structure yields a parallel plate waveguide (PPW). A PPW consists of two plates and possesses excellent characteristics such as simple structure, low profile, and low insertion loss. Unlike conventional waveguides, it can transmit TEM modes and has a wider bandwidth. There are relatively few reports on antennas based on two-dimensional PPW structures and related theories. The two-dimensional structure offers greater design freedom for antenna research, thus solving some challenges encountered in large-aperture antenna design. An ideal PPW structure does not exist because the parallel plates require boundary support. In actual research on PPW, one or more of its boundaries are usually closed, similar to a waveguide whose long side is much larger than its narrow side.

[0004] In the design of parallel-plate waveguide array antennas, line sources are often required. Unlike the open structure of an antenna, a line source is a closed structure that can output plane electromagnetic waves with equal phase distribution for antenna feeding. Traditional waveguide antenna line sources are mainly divided into two types based on amplitude distribution: discrete line sources and continuous line sources. The performance of the line source not only directly affects the antenna matching, but the amplitude and phase characteristics of the output electromagnetic wave also have a decisive impact on the antenna's radiation field gain and sidelobe level. Furthermore, the size of the line source directly determines the minimum size of the array antenna. Therefore, the design of the line source is crucial for achieving good overall antenna performance.

[0005] Chinese patent application number 201310409126.X discloses a broadband line source for feeding a planar waveguide CTS antenna. This broadband line source includes an H-plane sector horn antenna, a bias reflector, and a planar waveguide. The H-plane sector horn antenna and the bias reflector are disposed inside the planar waveguide, and the phase center of the H-plane sector horn antenna is located at the focal point of the bias reflector. This broadband line source, by placing the horn antenna at the focal point of the reflector, generates a plane wave with equal phase distribution at the reflector aperture surface through the reflector's radiated field. However, this broadband line source suffers from a relatively large overall longitudinal dimension, which is detrimental to the miniaturization design of broadband line sources.

[0006] Chinese Patent Application No. 201610523014.0 discloses a broadband line source for a planar CTS antenna, comprising a feed network, a first rectangular waveguide, and several H-plane single-ridge rectangular waveguide T-junctions of identical structural dimensions. The network serves as a power divider, consisting of an array of H-plane single-ridge rectangular waveguide T-junctions arranged with zero lateral spacing. This broadband line source uniformly distributes the electromagnetic wave energy input to the rectangular waveguide, resulting in a plane wave with equal amplitude and phase distribution at the output parallel plate waveguide. However, this broadband line source has the following problems: First, because the line source uses a power divider, while increasing the lateral output range, the longitudinal width of the line source increases exponentially. Such a feed source is not suitable for large-aperture, small-size array antennas. Second, in the design process of array antenna line sources, in order to meet the low sidelobe performance of the antenna, the line source is usually required to output plane waves with a cosine-like amplitude distribution. This broadband line source can only output plane waves with equal amplitude distribution, resulting in high antenna sidelobes when used as a line source.

[0007] Chinese patent application number 201621478793.9 discloses an H-plane horn line source, comprising an input rectangular waveguide, an H-plane horn connected to the input rectangular waveguide, and a metamaterial disposed on the aperture surface of the H-plane horn. The metamaterial includes a substrate and multiple conductive microstructures arranged in an array on the substrate. This line source achieves adjustable equivalent refractive index of electromagnetic waves on the aperture surface through the placement of the metamaterial, thus obtaining plane waves with equal phase distribution at the output port. However, this broadband line source has the following problems: First, the line source bandwidth is limited by the metamaterial bandwidth, and the designed line source is often a narrowband line source; second, the lateral distance of the line source output is limited, making it unsuitable for large-aperture array antennas.

[0008] Therefore, with the widespread application of large-aperture array antennas, the existing line source technology has the following problems: small output lateral size, narrow bandwidth, excessively large longitudinal size, and output amplitude distribution that does not meet the low sidelobe characteristics of the antenna. Summary of the Invention

[0009] Given the technical deficiencies of existing technologies, the main objective of this invention is to provide a reflective surface array line source based on a parallel plate waveguide to solve the problems of miniaturization, broadband, and output amplitude distribution of the line source when feeding large apertures.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A reflective surface array line source based on parallel plate waveguides includes a first parallel plate waveguide and a second parallel plate waveguide stacked sequentially, coupled with a corresponding waveguide power divider feed network. The first and second parallel plate waveguides are connected by a reflective surface array bend. The input port of the first parallel plate waveguide is connected to the output port of an H-plane horn array, and the input port of the H-plane horn array is connected to the output port of the waveguide power divider feed network. The output port of the second parallel plate waveguide is connected to a straight bend. This line source can effectively reduce the longitudinal size while increasing the lateral output range, and obtain a plane wave with uniform phase distribution and a "flat-top" amplitude distribution in a one-dimensional plane, thereby effectively reducing the size and manufacturing difficulty of large-aperture array antennas.

[0012] Furthermore, the reflector array bend is a cavity structure composed of two C-shaped structures A and N (N = 0, 1, 2, 3...) C-shaped structures B. The inner wall of the cavity is made of metal. The openings of both C-shaped structures A and B face inwards towards the line source structure, used to change the direction and phase distribution of electromagnetic wave propagation within the waveguide. The two C-shaped structures A are located on opposite sides of the reflector array bend, while the N C-shaped structures B are located between the two C-shaped structures A.

[0013] Furthermore, the C-type structures A and B are arranged sequentially along the magnetic field direction, and the C-type structures can be marked as n (n = 1, 2, ..., N+2) from one side to the other side of the reflector array bend.

[0014] Furthermore, the reflective array bend is symmetrical about the longitudinal central axis of the line source, and has two symmetrical first matching steps at the positions where it contacts the first parallel plate waveguide and the second parallel plate waveguide, which are used to change the direction of electromagnetic wave propagation.

[0015] Furthermore, the horizontal default of the line source is... Figure 1 In the direction where D is located, the longitudinal direction of the line source is perpendicular to the direction of the line source length D and parallel to the plane where the line source is located.

[0016] Furthermore, the first matching step is a rectangular step or a triangular step with a certain curvature. The first matching step can turn the propagation direction of electromagnetic waves passing through the first parallel plate waveguide by 180 degrees and enter the second parallel plate waveguide.

[0017] Furthermore, the straight elbow has a straight rotation arc in the lateral direction, and the straight elbow is composed of an L-shaped corner and a second matching step.

[0018] Furthermore, the second matching step is a rectangular step or a triangular step with a certain curvature. The second matching step can turn the propagation direction of the plane wave passing through the second parallel plate waveguide by 90 degrees and output it through the output port.

[0019] Furthermore, the longitudinal centerlines of the reflective surface array elbow and the straight elbow coincide.

[0020] Furthermore, the lateral rotation radius of both C-shaped structure A and C-shaped structure B satisfies the following formula:

[0021] X n 2 =4f n Y n n = 1, 2, ..., N+2

[0022] Among them, f n The range of values ​​is The constant, X n The axis is located in the direction of the line source length D and is tangent to the point where the curvature of the C-shaped structure is maximum. n The axis passes through the point of maximum curvature of the C-shaped structure and is parallel to the plane where the line source is located, and Y n The positive direction of the axis points inwards from the line source.

[0023] Furthermore, when the number N of the C-shaped structures B is even, the C-shaped structures B symmetrical about the longitudinal central axis of the line source have the same size; when the number N of the C-shaped structures B is odd, the transition surfaces on both sides of the central C-shaped structure B have the same size, and the remaining N-1 C-shaped structures B each have the same size as their symmetrical counterparts about the longitudinal central axis of the line source.

[0024] Furthermore, the lateral dimensions of the C-shaped structure A and the C-shaped structure B are D1 and D2, respectively. By adjusting D1 and D2, the amplitude distribution of the electromagnetic wave output by the line source can be adjusted.

[0025] Furthermore, the lateral dimension D2 of the N C-shaped structures B can be the same or different, depending on the design.

[0026] Furthermore, the H-plane horn array consists of two H-plane horns A and N H-plane horns B, wherein the two H-plane horns A are located on opposite sides of the array, and the N H-plane horns B are located between the two H-plane horns A. Adjacent H-plane horns are connected by transition surfaces formed by splicing together two or more inclined planes with different slopes.

[0027] Furthermore, the H-plane horn array is symmetrical about the longitudinal central axis of the line source, and its upper and lower wide surfaces are connected to the upper and lower surfaces of the first parallel plate waveguide, respectively.

[0028] Furthermore, the opening of the H-plane horn array faces the bend of the reflector array, and the electromagnetic waves radiated from the output port of the horn array are symmetrically distributed along the longitudinal central axis.

[0029] Furthermore, the H-surface horn A is composed of two transition surfaces and two planes, wherein the direction of the transition surfaces is the electric field direction and the direction of the planes is the magnetic field direction; the outer transition surface is an inclined plane with a constant slope, and the inner transition surface is a surface formed by splicing two or more inclined planes with different slopes one after the other. Adjacent inclined planes can be directly connected or a plane perpendicular to the direction of the line source length D can be added between them.

[0030] Furthermore, the upper and lower wide surfaces of the H-plane horn A are connected to the upper and lower surfaces of the first parallel plate waveguide, respectively. The opening of the H-plane horn A faces the C-shaped structure A of the reflector array bend. The beamwidth of the output cylindrical wave can be adjusted by adjusting the size of the horn opening. The two sides of the H-plane horn A are asymmetrical. The opening of the H-plane horn A is greater than λ, where λ is the waveguide wavelength of the highest frequency electromagnetic wave.

[0031] Furthermore, the H-surface horn B is composed of two transition surfaces and two planes, wherein the direction of the transition surfaces is the electric field direction and the direction of the planes is the magnetic field direction; both transition surfaces are formed by splicing together two or more inclined planes with different slopes, but the specific dimensions of the two transition surfaces are determined by the specific design and can be the same or different.

[0032] Furthermore, the upper and lower wide surfaces of the H-plane horn B are connected to the upper and lower surfaces of the first parallel plate waveguide, respectively. The opening of the H-plane horn B faces the C-shaped structure B of the reflector array bend. The beamwidth of the output cylindrical wave can be adjusted by adjusting the size of the horn opening. The H-plane horn B can be symmetrical or asymmetrical. The opening of the H-plane horn B is greater than λ, where λ is the waveguide wavelength of the highest frequency electromagnetic wave.

[0033] Furthermore, when the number N of the H-face horns B is even, the H-face horns B symmetrical about the longitudinal central axis of the line source have the same size; when the number N of the H-face horns B is odd, the transition surfaces on both sides of the H-face horn B at the center have the same size, and the remaining N-1 H-face horns B each have the same size as the H-face horn B symmetrical about the longitudinal central axis of the line source.

[0034] Furthermore, the number of C-shaped structures B in the reflective surface array bend is equal to the number of H-face horns B in the H-face horn array.

[0035] Furthermore, the 2+N input ports of the H-plane horn array are connected to the 2+N output ports of the waveguide power divider feed network. The waveguide power divider feed network is symmetrical along the longitudinal central axis of the line source. The upper and lower wide faces of the output ports of the waveguide feed network are respectively connected to the upper and lower wide faces of the input ports of the H-plane horn array.

[0036] Furthermore, the waveguide power divider feed network consists of a 2+N waveguide power divider structure. If the waveguide power divider structure is implemented using a ridge waveguide or a single ridge waveguide, or if the waveguide size of the power divider network is inconsistent with the size of the H-plane horn array input port, then a corresponding waveguide transition structure needs to be added to achieve the transition from the waveguide power divider feed network to the H-plane horn array input port.

[0037] Furthermore, the waveguide power divider network can be either a broadband structure or a narrowband structure.

[0038] Furthermore, the waveguide power divider structure can be a single-stage power divider or a multi-stage power divider structure. Moreover, the waveguide power divider structure can consist only of equal power dividers, or it can be a mixture of equal and unequal power dividers. Furthermore, the waveguide power divider feed network can be placed on the same layer as the H-plane horn array, or it can be placed on the layer below the H-plane horn array. When the waveguide power divider feed network is placed on the layer below the H-plane horn array, a corresponding matching step is needed to achieve the transition from the output port of the waveguide power divider feed network to the input port of the H-plane horn array.

[0039] Furthermore, the output port of the second parallel plate waveguide is located directly above the second parallel plate waveguide, and is used to connect parallel feeding or series feeding networks or radiation structures of CTS antennas and other antennas that require plane wave feed sources, so as to directly radiate electromagnetic waves.

[0040] Furthermore, the first parallel plate waveguide and the second parallel plate waveguide are separated by a thin metal plate. The upper, lower, and side walls of the first and second parallel plate waveguides are made of metal conductors, and the side walls can be covered with absorbing material.

[0041] Furthermore, the first parallel plate waveguide and the second parallel plate waveguide can be replaced by substrate integrated waveguides.

[0042] The present invention also provides an antenna comprising a reflective surface array line source of any of the forms described above, based on a parallel plate waveguide.

[0043] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0044] 1. The line source of the present invention has a simple design, low profile, and is easy to process. In the case of large-aperture lateral output, it can effectively reduce the overall longitudinal size of the line source, and thus can further reduce the overall size of the large-aperture array antenna.

[0045] 2. Since the parallel plate waveguide is used as the main structure of the line source, a broadband line source can be realized by using a broadband waveguide power divider feed network, and therefore it can be widely used as the feed source for broadband array antennas.

[0046] 3. The line source output amplitude distribution of this invention is a "flat-top" shape, which can meet the performance requirements of low sidelobes when used as an array antenna feed source. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0048] Figure 1 This is a perspective structural diagram of a broadband line source according to an embodiment of the present invention;

[0049] Figure 2 This is a side cross-sectional view of the broadband line source according to an embodiment of the present invention;

[0050] Figure 3 This is a schematic cross-sectional view of the first-layer parallel plate waveguide and broadband ridge waveguide power divider feed network of the broadband line source according to an embodiment of the present invention.

[0051] Figure 4 This is a schematic cross-sectional view of the second-layer parallel plate waveguide of the broadband line source according to an embodiment of the present invention;

[0052] Figure 5 This is a perspective structural schematic diagram of a broadband line source according to another embodiment of the present invention;

[0053] Figure 6 This is a side cross-sectional view of a broadband line source according to another embodiment of the present invention;

[0054] Figure 7 This is a cross-sectional schematic diagram of the first-layer parallel plate waveguide and broadband ridge waveguide power divider feed network of another embodiment of the present invention;

[0055] Figure 8 This is a schematic cross-sectional view of the second-layer parallel plate waveguide of a broadband line source according to another embodiment of the present invention.

[0056] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0058] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0059] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0060] like Figure 1 , 2 As shown, the reflector array line source based on parallel plate waveguides in this embodiment of the invention mainly consists of two sequentially stacked first parallel plate waveguides 5 and second parallel plate waveguides 6, along with a corresponding broadband ridge waveguide power divider feed network 1. The first parallel plate waveguide 5 and the second parallel plate waveguide 6 are connected via a reflector array bend 3. The input port of the first parallel plate waveguide 5 is connected to the output port of the H-plane horn array 2, and the input port of the H-plane horn array 2 is connected to the output port of the broadband ridge waveguide power divider feed network 1. The output port of the second parallel plate waveguide 6 is connected to a straight bend 4. This line source has a broadband structure, which can increase the lateral output range while effectively reducing the longitudinal size of the line source, obtaining a plane wave with uniform phase distribution and a "flat-top" amplitude distribution on a one-dimensional plane, thereby effectively reducing the volume and manufacturing difficulty of large-aperture array antennas.

[0061] By adjusting the longitudinal position of each H-face horn in the H-face horn array 2 and the phase center of the cylindrical wave, and by adjusting the rotation arc of the C-shaped structures A and B in the reflector array bend 3, the cylindrical wave generated by the H-face horns, after passing through the first parallel plate waveguide 5 and the reflector array bend 3, can obtain a plane wave with equal phase and a "flat-top" amplitude distribution along the lateral direction in the second parallel plate waveguide 6. This embodiment uses a rectangular waveguide for feeding; the overall outline is a metal cuboid, and the internal hollowed-out portion is a broadband ridge waveguide power divider feeding network and a parallel plate waveguide cavity structure. Electromagnetic waves are fed in through a rectangular waveguide port on the side and fed to the H-plane horn array 2 via a broadband ridge waveguide power divider network 1. The cylindrical waves in the H-plane horn array 2 converge after reaching the parallel plate waveguide cavity in front of the reflector array bend 3. After reflection by the first matching step 16 at the reflector array bend 3, the converged electromagnetic waves turn 180 degrees to reach the second parallel plate waveguide 6. After reflection by the second matching step 17 at the straight bend 4, they turn 90 degrees to output a plane wave. The input electromagnetic wave mode is the TE10 mode of the standard rectangular waveguide, and the output electromagnetic wave mode is the quasi-TEM mode of the parallel plate waveguide. The output quasi-TEM mode exhibits a "flat-top" shaped electric field amplitude distribution in the transverse direction of the overall structure, and the electric field phase is equally distributed.

[0062] like Figure 1 , 2 As shown, the parallel plate waveguide cavity, viewed from the side, mainly consists of an H-plane horn array 2, a first parallel plate waveguide 5, a second parallel plate waveguide 6, a reflective surface array bend 3, and a straight bend 4. The H-plane horn array 2 is at the same horizontal height as the first parallel plate waveguide 5 and the second parallel plate waveguide 6. The first parallel plate waveguide 5 and the second parallel plate waveguide 6 are placed parallel to each other, and are separated from each other by a thin metal plate 15 in the vertical direction. One end of the first parallel plate waveguide 5 is connected to the H-plane horn array 2; the other end of the first parallel plate waveguide 5 is connected to one end of the second parallel plate waveguide 6 through a reflective surface array elbow 3. The upper and lower surfaces of the reflective surface array elbow 3 are provided with two triangular first matching steps 16. The electromagnetic wave fed into the first parallel plate waveguide 5 passes through the reflective surface array elbow 3, and the plane wave propagation direction turns 180 degrees to reach the second parallel plate waveguide 6. The second parallel plate waveguide 6 is connected to the output port through a straight elbow 4. The plane wave fed into the second parallel plate waveguide 6 passes through the straight elbow 4, and the plane wave propagation direction turns 90 degrees to reach the output port.

[0063] Specifically, the reflective surface array elbow 3 is a cavity structure assembled from two C-shaped structures A 13 and two C-shaped structures B 14. The two C-shaped structures A are located on both sides of the reflective surface array elbow, and the two C-shaped structures B are located between the two C-shaped structures A, as shown below. Figure 3 As shown.

[0064] Specifically, the lateral rotation radians of both C-shaped structure A13 and C-shaped structure B14 satisfy formula X. n 2 =4f n Y n (n = 1, 2, 3, 4), where: f n The range of values ​​is The constant, X n The axis is located in the direction of the line source length D and is tangent to the point where the curvature of the C-shaped structure is maximum. n The axis passes through the point of maximum curvature of the C-shaped structure and is parallel to the plane where the line source is located, and Y n The positive direction of the axis points inwards from the line source. This can be achieved by adjusting... Figure 1 The D1 and D2 shown can adjust the amplitude distribution of the line source, thereby regulating the aperture efficiency and sidelobe level of the line source. In this embodiment, the obtained parameters are optimized to achieve better transmission performance and the required output plane wave.

[0065] like Figure 3 As shown, the broadband ridge waveguide power divider feed network 1 consists of one 1-to-2 equal power divider 7 and two 1-to-2 equal power dividers 8. The input electromagnetic wave, after passing through the 1-to-2 equal power divider 7, becomes two equal-power signals. Each of these two equal-power signals then passes through two 1-to-2 equal power dividers 8 to obtain four equal-power signals. The broadband ridge waveguide power divider feed network 1 can also achieve equal-amplitude, different-phase feeding of the H-plane horn array 2 by cascading equal and unequal power dividers, thereby adjusting the amplitude distribution of the line source and controlling the line source aperture efficiency and sidelobe level.

[0066] Specifically, the H-plane speaker array 2 consists of two H-plane speakers A and two H-plane speakers B, wherein the two H-plane speakers A are located on both sides of the H-plane speaker array 2, and the two H-plane speakers B are located between the two H-plane speakers A.

[0067] Specifically, the number of C-shaped structures B in the reflective surface array elbow 3 is equal to the number of H-face horns B in the H-face horn array.

[0068] Specifically, the H-face horn A consists of an outer transition surface 9, an inner transition surface 10, and two planes. The outer transition surface 9 is composed of inclined planes with a constant slope, while the inner transition surface 10 consists of two inclined planes with different slopes. The direction of the inclined planes is the electric field direction, and the direction of the planes is the magnetic field direction. The planes are in contact with the upper and lower surfaces of the parallel plate waveguide. The input port of the H-face horn A is placed along the central axis passing through the most convex point of the C-shaped structure A13 arc curve, and the input port of the H-face horn A is connected to the output port of the one-to-two power divider 8.

[0069] Specifically, the H-plane horn B consists of a transition surface 11, a transition surface 12, and two planes. Both transition surfaces 11 and 12 are composed of two inclined planes with different slopes. The direction of the inclined planes is the electric field direction, and the direction of the planes is the magnetic field direction. The planes contact the upper and lower surfaces of the parallel plate waveguide. The input port of the H-plane horn B is placed along the central axis passing through the most convex point of the arc curve of the C-shaped structure B14. The input port of the H-plane horn B is connected to the output port of the one-to-two power divider 8. The specific dimensions of transition surfaces 11 and 12 can be the same or different, depending on the design considerations. The horn's opening direction is the reflector array bend 3, and the horn opening size is greater than λ (λ is the waveguide wavelength of the highest frequency electromagnetic wave). The output beamwidth can be adjusted by adjusting the horn's opening size.

[0070] Based on the above principles, this invention can also, as needed, place the broadband ridge waveguide power divider / feed network in the layer below the H-plane horn array, designing a three-layer structure. The principle is similar to the structure described above; only corresponding bends need to be added between the broadband ridge waveguide power divider / feed network and the input port of the H-plane horn array to achieve effective connection between them. In this case, the line source can further reduce its longitudinal dimension while maintaining a constant lateral dimension. Furthermore, other waveguide structures can also be used to implement the broadband power divider / feed network. Additionally, the number N of C-type structures B in the reflector array bends and the number N of H-plane horn Bs in the H-plane horn array can be increased or decreased after weighing the ratio of the line source's lateral and longitudinal dimensions and the complexity of the waveguide power divider / feed network. Figure 5-8 As shown, N can be zero, in which case there are only C-shaped structures A and H-plane horn A. The ratio of the lateral to longitudinal dimensions of the line source decreases, but the broadband waveguide power divider feed network is simpler. Of course, increasing N can increase the lateral dimension of the line source while keeping the longitudinal dimension constant, increasing the ratio of lateral to longitudinal dimensions, which is beneficial for miniaturization. However, the corresponding broadband waveguide power divider feed network will become more complex. Therefore, a trade-off needs to be made based on the choice of the lateral to longitudinal dimension ratio of the line source and the complexity of the broadband waveguide power divider feed network.

[0071] The above describes specific embodiments of the present invention. Those skilled in the art can fabricate the broadband line source of this embodiment by applying the methods disclosed in this invention and some alternative methods that do not require creative effort. The linear source of the present invention is suitable for use as a line source for large-aperture broadband array antennas.

[0072] The embodiments described above are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A reflective surface array line source based on a parallel plate waveguide, characterized in that, It includes a first parallel plate waveguide, a second parallel plate waveguide, and a corresponding waveguide power divider feed network arranged in sequence. The first parallel plate waveguide and the second parallel plate waveguide are connected by a reflector array elbow. The output port of the second parallel plate waveguide is connected to a straight elbow. The input port of the first parallel plate waveguide is connected to the output port of the H-plane horn array. The input port of the H-plane horn array is connected to the output port of the waveguide power divider feed network. The reflector array bend consists of two C-shaped structures A and N C-shaped structures B, where N = 0, 1, 2, 3, ... . The inner wall of its cavity is made of metal. The openings of the C-shaped structures face the inner side of the line source structure, which is used to change the propagation direction and phase distribution of electromagnetic waves in the waveguide. The C-shaped structures A are located on both sides of the reflector array bend, and the C-shaped structures B are located between the C-shaped structures A. The C-shaped structures A and B are arranged sequentially along the magnetic field direction, and the C-shaped structures are marked as n from one side of the reflector array bend to the other side, where n = 1, 2, ..., N+2.

2. The reflective surface array line source based on parallel plate waveguides according to claim 1, characterized in that, The H-plane horn array consists of two H-plane horns A and N H-plane horns B, wherein the H-plane horns A are located on both sides of the H-plane horn array, and the H-plane horns B are located between the H-plane horns A; the H-plane horns A and H-plane horns B are arranged sequentially along the magnetic field direction. The H-plane horn array is symmetrical about the longitudinal central axis of the line source, and its upper and lower wide planes are connected to the upper and lower surfaces of the first parallel plate waveguide, respectively. The longitudinal direction of the line source is perpendicular to the direction of the line source length D and parallel to the plane where the line source is located; The opening of the H-plane horn array faces the bend of the reflector array, and the electromagnetic waves radiated from the output port of the horn array are symmetrically distributed along the longitudinal central axis.

3. The reflective surface array line source based on parallel plate waveguides according to claim 2, characterized in that, The H-surface horn A consists of two transition surfaces and two planes, wherein the direction of the transition surfaces is the electric field direction and the direction of the planes is the magnetic field direction; the outer transition surface is an inclined plane with a constant slope, and the inner transition surface is a surface formed by splicing two or more inclined planes with different slopes one after the other. Adjacent inclined planes can be directly connected or a plane perpendicular to the direction of the line source length D can be added between them.

4. The reflective surface array line source based on parallel plate waveguides according to claim 2, characterized in that, The H-face horn B consists of two transition surfaces and two planes, wherein the direction of the transition surfaces is the electric field direction and the direction of the planes is the magnetic field direction; the transition surfaces on both sides are formed by splicing two or more inclined planes with different slopes one after the other, but the specific dimensions of the transition surfaces on both sides depend on the specific design and can be the same or different. When the number N of H-face horns B is even, the H-face horns B symmetrical about the longitudinal central axis of the line source have the same size; when the number N of H-face horns B is odd, the transition surfaces on both sides of the central H-face horn B have the same size, and the remaining N-1 H-face horns B each have the same size as the H-face horn B symmetrical about the longitudinal central axis of the line source.

5. The reflective surface array line source based on parallel plate waveguides according to claim 1, characterized in that, The reflective array bend is symmetrical about the longitudinal central axis of the line source. It has two symmetrical first matching steps at the positions where it contacts the first parallel plate waveguide and the second parallel plate waveguide, which are used to change the direction of electromagnetic wave propagation. The first matching step is a rectangular step or a triangular step with a certain curvature. The first matching step can turn the propagation direction of electromagnetic waves passing through the first parallel plate waveguide by 180 degrees and enter the second parallel plate waveguide. The straight elbow has a straight rotation arc in the lateral direction, and the straight elbow is composed of an L-shaped corner and a second matching step; The second matching step is a rectangular step or a triangular step with a certain curvature. The second matching step can turn the propagation direction of the plane wave passing through the second parallel plate waveguide by 90 degrees and output it through the output port. The longitudinal centerlines of the reflective surface array elbow and the straight elbow coincide.

6. The reflective surface array line source based on parallel plate waveguides according to claim 1, characterized in that, The lateral rotation radius of the C-shaped structure A and C-shaped structure B satisfies the following formula: in, The range of values ​​is The constant, The axis is located in the direction of the line source length D and is tangent to the point where the curvature of the C-shaped structure is at its maximum. The axis passes through the point of maximum curvature of the C-shaped structure and is parallel to the plane where the line source is located. The positive direction of the axis points inwards from the line source; When the number N of the C-shaped structures B is even, the C-shaped structures B symmetrical about the longitudinal central axis of the line source have the same size; when the number N of the C-shaped structures B is odd, the two sides of the C-shaped structure B at the center have the same size, and the remaining N-1 C-shaped structures B each have the same size as the C-shaped structure B symmetrical about the longitudinal central axis of the line source.

7. The reflective surface array line source based on parallel plate waveguides according to claim 1, characterized in that, The first parallel plate waveguide and the second parallel plate waveguide are separated by a thin metal plate; the upper, lower, and side walls of the first and second parallel plate waveguides are made of metal conductors, and the side walls are covered with absorbing material.

8. The reflective surface array line source based on parallel plate waveguides according to claim 1, characterized in that, The waveguide power divider feed network is set along the longitudinal central axis of the line source, and its upper and lower wide surfaces are connected to the upper and lower surfaces of the H-plane horn array input port, respectively. The waveguide power divider feed network can be placed on the same layer as the H-plane horn array or on the layer below the H-plane horn array. The input port of the waveguide power divider feed network is connected to the rectangular waveguide. The rectangular waveguide is arranged along the longitudinal central axis of the line source, and the upper and lower wide faces of the rectangular waveguide are respectively connected to the upper and lower wide faces of the waveguide power divider feed network input port; the main mode of the rectangular waveguide is TE10 mode; The first parallel plate waveguide, the second parallel plate waveguide, and the waveguide power divider feed network can be replaced by substrate integrated waveguides.

9. The reflective surface array line source based on parallel plate waveguides according to claim 1, characterized in that, The output port of the second parallel plate waveguide is located directly above the second parallel plate waveguide and is used to connect the CTS antenna.

10. An antenna, characterized in that, The antenna comprises a reflective surface array line source based on a parallel plate waveguide as described in any one of claims 1 to 9.

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