A broadband radiating leaky-wave horn antenna with customizable profile

Abstract

This invention belongs to the field of antenna technology and relates to the design of horn antennas. Specifically, it provides a broadband radiating leaky horn antenna with a customizable profile, which is composed of multiple H-plane leaky horns stacked together. Each H-plane leaky horn consists of a feed network, a leaky ground coplanar waveguide, a slow-wave parallel plate waveguide, and a matching structure. The feed network is connected to two leaky ground coplanar waveguides, which are arranged in an open horn shape to form the leaky horn. A strip-shaped slot is formed on the center line of the leaky horn, and slow-wave parallel plate waveguides are respectively arranged in the triangular regions between the horn arms and the strip-shaped slot. A matching structure is arranged on the aperture surface of the leaky horn. Based on this structure, the leaky horn antenna provided by this invention achieves phase error suppression while maintaining broadband radiation characteristics, and the leaky horn antenna has a customizable profile, which is beneficial for miniaturization.

Description

Technical Field

[0001] This invention belongs to the field of antenna technology and relates to the design of horn antennas, specifically providing a broadband radiating leaky horn antenna with a customizable profile. Background Technology

[0002] Traditional horn antennas typically employ optimal horn standards to minimize the negative impact of phase errors and ensure the horn achieves a specified directivity; however, phase errors still exist even in optimal horns. To address this issue, techniques for suppressing phase errors through compensation mechanisms have been proposed. One approach is to drill air holes or perforations along the horn-shaped region of the filling material, which act as phase compensation lenses. By appropriately optimizing the diameter and periodicity of the air holes or the longitudinal length of the perforated region, the local field along the two open sides of the horn propagates faster than the central field, thus correcting the phase distribution of the aperture field. Similarly, another effective method is to employ slow-wave techniques along the central region of the horn, such as periodically loaded metallized blind holes or metal blocks. These slow down the phase velocity of the central field, thereby compensating for the phase distribution.

[0003] While the aforementioned efforts can effectively reduce phase error and, to some extent, make the horn profile designable, phase error still exists inherently. In contrast, leaky-wave enabled horn antennas (or simply leaky-wave horn antennas) utilize the inherent planar wavefront characteristics of the wedge-shaped region of the leaky waveguide, thus exhibiting phase error-free properties. The concept of leaky-wave horn antennas originated from the leaky waveguide feeding system proposed in the literature "K. Maamria, T. Wagatsuma, and T. Yoneyama, “Leaky NRD guide as a feeder for microwave planar antennas,” IEEE Trans. Antennas Propag., vol. 41, no. 12, pp. 1680–1686, Dec. 1993.”, in which two leaky non-radiating dielectric waveguides are placed in a horn shape to feed a parallel plate waveguide (PPW) slot antenna array. Building upon this, the leaky wave horn antenna has been further developed into two collinear leaky substrate integrated waveguides (SIWs) for constructing horn feeds or surface wave transmitters, as shown in the literature “L. Wang and G. Goussetis, “Leaky wave fed substrate integrated horn antenna,” in Proc. 13th UK-Europe-China Workshop Millimetre-WavesTerahertz Technol. (UCMMT), Tianjin, China, Aug. 2020, pp. 1–3.”

[0004] Although leaky wave horn antennas have the advantage of phase error suppression, the inherent dispersive nature of leaky waveguides (SIW) results in narrow-band characteristics for existing leaky wave horn antennas and feed lines. Therefore, how to achieve a leaky wave horn antenna design with customizable profile, broadband radiation, and phase error suppression has become the research focus of this invention. Summary of the Invention

[0005] The purpose of this invention is to provide a broadband radiating leaky horn antenna with a customizable profile, which achieves phase error suppression while maintaining broadband radiation characteristics, and the leaky horn antenna has a customizable profile, which is beneficial for miniaturization.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A broadband radiating leaky horn antenna with a customizable profile is characterized in that it is composed of multiple H-plane leaky horns stacked along the Z-axis, the H-plane leaky horns are arranged along the XOY plane, and adjacent H-plane leaky horns are separated by an insulating metal plate, and an air gap is provided between the insulating metal plate and the H-plane leaky horns.

[0008] The H-plane leaky wave horn consists of a feeding network, a leaky wave grounded coplanar waveguide, a slow-wave parallel plate waveguide, and a matching structure. The feeding network is connected to two leaky wave grounded coplanar waveguides, which are arranged in an open horn shape to form a leaky wave horn. A strip-shaped slot is opened on the center line of the leaky wave horn, and slow-wave parallel plate waveguides are respectively set in the triangular area between the horn arm and the strip-shaped slot. A matching structure is set on the aperture surface of the leaky wave horn.

[0009] Furthermore, the power supply network is composed of a rectangular waveguide to substrate integrated waveguide transition structure, a substrate integrated waveguide one-to-two power divider, and two substrate integrated waveguide to ground coplanar waveguide transition structures connected in sequence.

[0010] Furthermore, the leaky wave grounding coplanar waveguide includes: a substrate, a lower metal ground, a central metal conductor strip, two side metal conductors, and short-circuit metal pillars. The lower metal ground is located on the lower surface of the substrate, the central metal conductor strip and the two side metal conductors are located on the upper surface of the substrate, and the two side metal conductors located outside the leaky wave horn are connected to the lower metal ground through a row of short-circuit metal pillars.

[0011] Furthermore, the slow-wave parallel plate waveguide is composed of several periodically arranged unit structures, each unit structure consisting of a substrate and metal rings symmetrically arranged on its upper and lower surfaces. Even further, the metal rings can be square, circular, or polygonal.

[0012] Furthermore, the matching structure consists of two rows of triangular metal patches disposed on the upper surface of the substrate.

[0013] Furthermore, the leakage constant of the grounded coplanar waveguide satisfies:

[0014] ,

[0015] in, The leakage constant, The target radiation aperture length, Let be the waveguide wavelength along the propagation mode field.

[0016] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0017] This invention provides a broadband radiating leaky horn antenna with a customizable profile. It creatively introduces a grounded coplanar waveguide (GCPW) to construct the leaky horn, utilizing the weak dispersion quasi-TEM mode of the GCPW to reduce the correlation between the leaky horn's leakage angle and frequency. This allows the planar wavefront characteristics of the leaky horn to be maintained continuously over a wide bandwidth, ultimately resulting in broadband radiation behavior. Simultaneously, by combining a slow-wave parallel plate waveguide with this leaky horn, a larger flare angle is achieved. For a given radiating aperture length, the longitudinal length of the horn antenna can be shortened, resulting in a more compact structure and miniaturization. Furthermore, based on the above-described leaky horn antenna structural design, this invention establishes a mathematical model relating the radiating aperture length, horn flare angle, and leakage constant. This model is further developed by setting the leakage constant of the corresponding leaky waveguide. and leak angle Free to choose Zhang Jiao Or equivalent longitudinal length This allows for a customizable profile of the leaky horn. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the broadband radiating leaky horn antenna with a customizable profile in this invention.

[0019] Figure 2 This is a schematic diagram of the H-plane leakage wave horn in this invention.

[0020] Figure 3 This is a schematic diagram of the power supply network in this invention.

[0021] Figure 4 This is a schematic diagram of the leakage grounded coplanar waveguide in this invention.

[0022] Figure 5 This is a schematic diagram of the unit structure of the slow-wave parallel plate waveguide in this invention.

[0023] Figure 6 This is a schematic diagram of the unit structure of the matching structure in this invention.

[0024] Figure 7 This is a schematic diagram of the leaky horn antenna in this invention.

[0025] In the above figures, 1 is the feed network, 2 is the leakage wave grounding coplanar waveguide, 3 is the slow wave parallel plate waveguide, 4 is the matching structure, 5 is the matrix waveguide to substrate integrated waveguide transition structure, 6 is the substrate integrated waveguide 1 to 2 power divider, 7 is the substrate integrated waveguide to grounding coplanar waveguide transition structure, 8 is the lower metal ground, 9 is the central metal conductor strip, 10 are the two side metal conductors, 1 is the metal short-circuit post, 12 is the square metal ring, 13 is the triangular metal patch, and 14 is the isolation metal plate. Detailed Implementation

[0026] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] This embodiment provides a broadband radiating leaky horn antenna with a customizable profile, such as... Figure 1 As shown, it is composed of multiple H-plane leakage horns stacked along the Z-axis. The H-plane leakage horns are arranged along the XOY plane, and adjacent H-plane leakage horns are separated by a layer of insulating metal plate 14. An air gap is provided between the insulating metal plate and the H-plane leakage horns to ensure normal radiation of the H-plane leakage horns.

[0028] The H-plane leakage horn, such as Figure 2 As shown, it consists of a feed network 1, a leakage grounded coplanar waveguide 2, a slow-wave parallel plate waveguide 3, and a matching structure 4; the feed network is as follows: Figure 3 As shown, the structure is composed of a rectangular waveguide (WR15) to substrate integrated waveguide (SIW) transition structure 5, a substrate integrated waveguide one-to-two power divider 6, and two substrate integrated waveguide to ground coplanar waveguide transition structures 7 connected in sequence. The two substrate integrated waveguide to ground coplanar waveguide transition structures are correspondingly connected to two leakage ground coplanar waveguides 2, and the two leakage ground coplanar waveguides are arranged in an open horn shape to form a leakage horn for radiation. To reduce the mutual interference of electromagnetic waves radiated between the two leakage ground coplanar waveguides, a symmetrical center line is formed between the two ground coplanar waveguides. A strip-shaped slot is made, and the strip-shaped slot runs through the entire H-plane leaky horn along the Z-axis. At the same time, in order to ensure that the electromagnetic waves radiated by the leaky horn are still plane waves when they reach the aperture surface of the leaky horn, slow-wave parallel plate waveguides 3 are respectively set in the triangular region between the inner side of each leaky grounded coplanar waveguide (i.e., the inner side of the leaky horn, and the short-circuited metal pillar is removed) and the strip-shaped slot. Furthermore, in order to ensure that the electromagnetic waves radiated into free space by the leaky grounded coplanar waveguide are not reflected back, a matching structure consisting of two rows of triangular patches is added to the aperture surface of the leaky horn.

[0029] The leakage grounded coplanar waveguide, such as Figure 4 As shown, it includes: a substrate, a lower metal ground, a central metal conductor, two side metal conductors, and short-circuit metal pillars. The lower metal ground is located on the lower surface of the substrate, and the central metal conductor and the two side metal conductors are located on the upper surface of the substrate. The two side metal conductors located outside the leakage horn are connected to the lower metal ground through a row of short-circuit metal pillars.

[0030] The slow-wave parallel plate waveguide 3 is composed of several periodically arranged unit structures, as shown in the figure below. Figure 5 As shown, it consists of a substrate and square metal rings 12 symmetrically arranged on its upper and lower surfaces.

[0031] The matching structure is as follows: Figure 6 As shown, it consists of two rows of triangular metal patches 13 disposed on the upper surface of the substrate.

[0032] In terms of working principle:

[0033] For traditional horn antennas, optimal design can be achieved if the following criteria are met:

[0034] (1)

[0035] in, This indicates the waveguide wavelength of the horn along the propagation mode field. and It is called having a given radial aperture length The optimal longitudinal length and angle of the horn;

[0036] In contrast, leakage horns, such as Figure 7 As shown, its radiation aperture length Zhang Jiao and longitudinal length It can be theoretically associated with leaky waveguides, such as the complex propagation constant. ( ), Leakage angle and power leakage efficiency Specifically, the angle of the leaky horn. It is the leaky angle. Twice, represented as:

[0037] (2)

[0038] in, The mode wavenumber represents the flare area. This represents the phase constant, and also relates to the power leakage efficiency. The length of the radiation aperture of the leaky waveguide and leakage constant satisfy :

[0039] (3)

[0040] Simultaneously satisfying geometric relations:

[0041] (4)

[0042] in, The length of the horn arm;

[0043] Therefore, substituting equation (4) into equation (3) and setting... After reaching 95%, the angle of the leaky horn Radiation aperture length and leakage constant The relationship can be represented as:

[0044] (5)

[0045] Equation (1) shows that once the optimal aperture length of the horn is predetermined, there is almost no freedom to set its longitudinal length and aperture angle, which means that the customizability of the optimal horn profile is severely limited; however, this is not the case for leaky wave horns, as can be seen from equations (2) and (5), because of the leakage constant of the leaky waveguide and leak angle The design allows for flexibility, enabling leaky horns to achieve customizable profiles, for example, in designs with a target radiation aperture length. When constructing a leaky horn, simply adjust the leakage constant of the leaky waveguide accordingly. and leak angle Then one can freely choose Zhang Jiao. Or equivalent longitudinal length Therefore, it can be seen that the leaky horn antenna proposed in this invention can achieve a customized profile.

[0046] Furthermore, for a given radiation aperture length Only when the angle (longitudinal length) of the leaky horn is greater than (shorter than) the corresponding optimal horn, i.e., achieving a more compact profile design, can the leaky horn concept be practically meaningful. Therefore, setting... The leakage constant of the leakage waveguide is derived from equations (1) and (5). It should be greater than the lower limit:

[0047] (6)

[0048] (7)

[0049] Where p is the period of the leaky waveguide element, S 11 and S 22 S is the reflection coefficient of the leaky waveguide element. 21 and S 12 denoted as the transmission coefficient of the leaky waveguide element.

[0050] Furthermore, in order to make leaky wave horns more competitive than traditional horns, they should maintain the wide operating bandwidth characteristic typically found in traditional horns. This requires a specific leak angle in the leaky waveguide. The leakage wave should remain unchanged over a wide frequency band. Therefore, this invention proposes a grounded coplanar waveguide as the leakage waveguide.

[0051] In summary, this invention proposes a leaky horn antenna based on a grounded coplanar waveguide and a slow-wave parallel plate waveguide, which can suppress phase errors and has the advantages of customizable profile and wide operating bandwidth. Specifically, based on the weakly dispersive quasi-TEM mode supported in the grounded coplanar waveguide and the non-dispersive TEM mode propagating in the parallel plate waveguide, the leakage angle of the leaky horn is optimized. With low frequency dependence, the planar wavefront characteristics of the leaky wave horn can be maintained over a wide bandwidth, thus giving the leaky wave horn broadband radiation behavior. At the same time, the slow-wave parallel plate waveguide has a higher equivalent relative permittivity, which can give the leaky wave horn a larger opening angle. Therefore, for a given radiation aperture length, the longitudinal length of the horn will be shorter and the structure more compact. The slow-wave parallel plate waveguide can be composed of structures including but not limited to square metal rings, circular metal rings and polygonal metal rings etched on the upper and lower metal layers of the substrate.

[0052] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All disclosed features, or steps in all methods or processes, may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A broadband radiating leaky horn antenna with a customizable profile, characterized in that, It is composed of multiple H-plane leakage wave horns stacked along the Z-axis direction. The H-plane leakage wave horns are arranged along the XOY plane, and adjacent H-plane leakage wave horns are separated by a layer of insulating metal plate, and an air gap is provided between the insulating metal plate and the H-plane leakage wave horn. The H-plane leaky wave horn consists of a feeding network, a leaky wave grounded coplanar waveguide, a slow-wave parallel plate waveguide, and a matching structure. The feeding network is connected to two leaky wave grounded coplanar waveguides, which are arranged in an open horn shape to form a leaky wave horn. A strip-shaped slot is opened on the center line of the leaky wave horn, and slow-wave parallel plate waveguides are respectively set in the triangular area between the horn arm and the strip-shaped slot. A matching structure is set on the aperture surface of the leaky wave horn.

2. The broadband radiating leaky horn antenna with customizable profile according to claim 1, characterized in that, The power supply network consists of a rectangular waveguide to substrate integrated waveguide transition structure, a substrate integrated waveguide one-to-two power divider, and two substrate integrated waveguide to ground coplanar waveguide transition structures connected in sequence.

3. The broadband radiating leaky horn antenna with a customizable profile according to claim 1, characterized in that, The leaky ground coplanar waveguide includes: a substrate, a lower metal ground, a central metal conductor strip, two side metal conductors, and short-circuit metal pillars. The lower metal ground is located on the lower surface of the substrate, the central metal conductor strip and the two side metal conductors are located on the upper surface of the substrate, and the two side metal conductors located outside the leaky horn are connected to the lower metal ground through a row of short-circuit metal pillars.

4. The broadband radiating leaky horn antenna with a customizable profile according to claim 1, characterized in that, The slow-wave parallel plate waveguide is composed of several periodically arranged unit structures, each unit structure consisting of a substrate and metal rings symmetrically arranged on its upper and lower surfaces.

5. The broadband radiating leaky horn antenna with a customizable profile according to claim 4, characterized in that, Furthermore, the metal ring may be a square metal ring, a circular metal ring, or a polygonal metal ring.

6. The broadband radiating leaky horn antenna with customizable profile according to claim 1, characterized in that, The matching structure consists of two rows of triangular metal patches disposed on the upper surface of the substrate.

7. The broadband radiating leaky horn antenna with customizable profile according to claim 1, characterized in that, The leakage constant of the grounded coplanar waveguide with leakage wave meets the following requirements: ， in, The leakage constant, The target radiation aperture length, Let be the waveguide wavelength along the propagation mode field.

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