Compact ultra-wideband dual-polarized four-ridge Vivaldi antenna

Abstract

The invention discloses a compact ultra-wideband dual-polarization four-ridge Vivaldi antenna, which belongs to the technical field of microwave and millimeter wave antennas, and comprises a radiation body, two groups of coaxial feed structures which are orthogonally arranged and a base, the radiation body comprises two groups of polarized radiation pairs which are orthogonally arranged at 90 degrees, each group of polarized radiation pair is composed of two symmetrical ridge-shaped radiation arms, and a tapered slot line which is widened from a feed end to a radiation port end is formed between the two arms; the two groups of coaxial feed structures are respectively corresponding to the two groups of polarized radiation pairs to form a differential feed structure; the base is provided with two groups of orthogonal U-shaped backing cavities which are respectively corresponding to the two groups of polarized radiation pairs. Under the compact size of 47mm * 47mm * 62mm, 6GHz-50GHz ultra-wide frequency band coverage is realized, the full-band voltage standing-wave ratio is smaller than or equal to 2.0, the port isolation is larger than or equal to 15dB, the actual gain is larger than or equal to 5dBi, meanwhile, a stable end-fire radiation directional diagram is achieved, and the technical problem that an existing ultra-wide-band antenna cannot give consideration to wide bandwidth, high isolation, stable radiation and miniaturization at the same time is solved.

Description

Technical Field

[0001] This invention belongs to the field of microwave and millimeter-wave antenna technology, specifically relating to a compact ultrawideband dual-polarized four-ridged Vivaldi antenna. Background Technology

[0002] With the rapid development of 5G-Advanced, 6G communication and millimeter-wave radar technology, modern electronic systems have placed stringent requirements on antenna performance in multiple dimensions: they must simultaneously cover an ultra-wide operating frequency band of 6GHz-50GHz, have orthogonal dual-polarization diversity capability, maintain a stable end-fire radiation pattern across the entire frequency band, have excellent impedance matching and high port isolation, and at the same time meet engineering requirements for miniaturization, easy integration and easy fabrication.

[0003] Existing ultra-wideband dual-polarized antennas mainly fall into two technical categories: The first type is the traditional four-ridged horn antenna, which can achieve ultra-wideband impedance matching with its four-ridged loading structure, and has excellent polarization isolation and stable radiation characteristics. However, it has inherent defects: it is bulky, the low-frequency cutoff frequency is limited by the aperture size, and the axial length needs to be greatly increased to cover the 6GHz low-frequency band. It cannot be adapted to space-constrained miniaturized systems, and it is extremely difficult to integrate with planar radio frequency circuits.

[0004] The second type is the conventional dual-polarized Vivaldi antenna. As an end-fire traveling-wave antenna, it can achieve broadband radiation with its tapered slot line structure. The structure is planar and easy to integrate. However, the existing dual-polarization scheme has obvious technical shortcomings: the coupling between orthogonal polarization channels is serious, and the port isolation across the entire frequency band is difficult to meet the requirements; the beamwidth fluctuates drastically in the ultra-wideband range of 6GHz-50GHz, the gain in the low-frequency band is low, and the aperture diffraction in the high-frequency band causes pattern distortion; especially in the millimeter-wave high-frequency band, the impedance matching performance and radiation efficiency are significantly degraded, making it impossible to achieve stable operation across the entire frequency band.

[0005] Current ultra-wideband antenna designs often focus solely on expanding bandwidth, increasing gain, or reducing size, failing to systematically solve the core technical challenges of simultaneously achieving low VSWR, high isolation, stable beam, and miniaturization within the 6GHz-50GHz ultra-wideband frequency range. Consequently, they cannot meet the comprehensive performance requirements of modern electronic systems for ultra-wideband dual-polarized antennas. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a compact ultra-wideband dual-polarized quad-ridge Vivaldi antenna. This invention solves the technical pain point that existing ultra-wideband dual-polarized antennas cannot achieve excellent impedance matching, high port isolation, stable radiation characteristics and compact structure in the full frequency band of 6GHz-50GHz. It achieves high-performance radiation in the full frequency band from microwave to millimeter wave with a very small physical size, while ensuring that the structure is easy to manufacture and easy to integrate with planar radio frequency systems.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A compact ultrawideband dual-polarized quad-ridge Vivaldi antenna includes a radiating body, two sets of orthogonally arranged coaxial feed structures, and a base, characterized in that: The radiating body includes two sets of polarized radiating pairs, which are arranged in a 90° orthogonal cross in space to form a four-ridge radiating structure. Each set of polarized radiating pairs includes two symmetrically arranged ridge-shaped radiating arms. The feed ends of the two ridge-shaped radiating arms in the same set are arranged opposite each other, and the radiating ports open outward. A gradually widening groove line is formed between the two arms from the feed end to the radiating port end. The narrow slot at the feed end of the gradually widening groove line is the feed throat of the antenna, which serves as the coupling feed area for radio frequency signals. The two sets of coaxial feed structures correspond one-to-one with the two sets of polarization radiation pairs. The outer conductor of the coaxial feed structure is electrically connected to the feed end of any ridge radiation arm in the corresponding polarization radiation pair, and its inner conductor passes through the feed throat and is electrically connected to the feed end of the other ridge radiation arm in the corresponding polarization radiation pair, thus forming a differential feed structure to achieve smooth impedance transformation in the ultra-wideband range and effectively excite the traveling wave current on the ridge radiation arm. The base is located at the bottom of the feed end of the radiating body. Two sets of orthogonally arranged U-shaped backing cavities are formed on the base, and the two sets of U-shaped backing cavities correspond one-to-one with the two sets of polarization radiation pairs. The openings of the U-shaped backing cavities face the radiation port end of the radiating body. The two side walls of the cavity are fixed and electrically connected to the bottom of the feed end of the two ridge-shaped radiation arms of the corresponding polarization radiation pairs. The cavity structure constrains the current distribution of the feed end, improves the impedance matching in the low-frequency band, suppresses back radiation, and enhances the isolation between orthogonal polarization channels.

[0008] Furthermore, the outer contour of the ridge-shaped radiating arm is defined using a modified exponential gradient curve. Based on the traditional exponential gradient curve, a low-frequency aperture enhancement linear term is introduced to expand the low-frequency operating bandwidth and optimize impedance matching and radiation efficiency at the 6GHz low-frequency end. The expression for the modified exponential gradient curve is: ; In the formula, Antenna axial position The vertical distance from the edge of the ridge-shaped radiating arm to the central axis of the antenna; This is the initial half-slot width of the feed throat; It is an exponential growth rate and satisfies ; The axial coordinate of the antenna has a range of values. , The total axial length of the radiating body is given. The maximum half-width of the antenna's radiating port; This is the low-frequency aperture enhancement linear term.

[0009] Furthermore, the radiating end edge of the ridge-shaped radiating arm is provided with at least one set of slot structures. The slotting direction of the slot structures is parallel to the antenna axis, which is used to suppress electromagnetic edge diffraction of the radiating aperture, optimize the symmetry of the radiation pattern in the high-frequency band, and improve the directional radiation intensity and gain stability.

[0010] Furthermore, the metal layer of the radiating body is 3mm thick, and the metal edges of all ridge-shaped radiating arms are chamfered at 45° with a chamfer width of 0.4mm, which effectively suppresses electromagnetic scattering at the metal edges, reduces high-frequency signal interference, and avoids pattern distortion.

[0011] Furthermore, the coaxial feed structure adopts a 2.4mm RF coaxial connector. The inner conductor of the coaxial feed structure is provided with an impedance matching section with a length of 5.5mm, and the end of the impedance matching section is welded and fixed to the feed end of the ridge-shaped radiating arm. Through the size optimization of the matching section, impedance matching of the entire frequency band from 6GHz to 50GHz is achieved, reducing signal reflection.

[0012] Furthermore, the U-shaped backing cavity has a groove depth of 19mm and a groove width that matches the width of the feed throat of the corresponding radiating pair, thereby optimizing low-frequency performance without increasing the overall size of the antenna.

[0013] Furthermore, the antenna has an overall size of 47mm×47mm×62mm and operates in the 6GHz-50GHz frequency band, achieving a compact design that can be directly integrated into space-constrained miniaturized electronic systems.

[0014] Furthermore, the port isolation between the two sets of coaxial feed structures is ≥20dB in the 6GHz-36GHz frequency band and ≥15dB in the 36GHz-50GHz frequency band.

[0015] Furthermore, the antenna has a voltage standing wave ratio (VSWR) ≤ 2.0 and an actual gain ≥ 5 dBi across the entire 6 GHz-50 GHz frequency band, and a peak actual gain ≥ 10 dBi at the 37.5 GHz frequency point.

[0016] Furthermore, the 3dB beamwidth of the antenna exhibits a smooth narrowing trend as the operating frequency increases, with a 3dB beamwidth of 93.3° at the 6GHz frequency point and a 3dB beamwidth of 24.3° at the 50GHz frequency point.

[0017] The beneficial effects of this invention are as follows: 1. This invention deeply integrates the four-ridge loading structure with the gradient slot line technology of the Vivaldi antenna. The four-ridge radiation structure is formed by two sets of orthogonally arranged cross-shaped ridge radiation pairs. It retains the advantages of Vivaldi antennas such as planarity, easy integration, and wide bandwidth, while inheriting the characteristics of high isolation and stable radiation of the four-ridge horn antenna. It systematically solves the core technical pain points of existing dual-polarized ultra-wideband antennas. In the ultra-wideband of 6GHz-50GHz, it simultaneously achieves excellent impedance matching of VSWR≤2.0, high port isolation of ≥20dB, smooth beamwidth, and stable end-fire radiation pattern.

[0018] 2. This invention, through the design of a modified exponential gradient curve, introduces a low-frequency aperture enhancement linear term on the basis of the traditional exponential gradient curve. Combined with the orthogonal U-shaped backing cavity structure on the base, it extends the low-frequency cutoff frequency to 6GHz with a very small axial dimension, while suppressing back radiation and improving low-frequency gain. This solves the contradiction between low-frequency coverage and miniaturization in traditional ultra-wideband antennas.

[0019] 3. This invention optimizes the electromagnetic performance of the millimeter-wave high-frequency band in multiple dimensions through a radiating port end slot structure, metal edge chamfering treatment, and impedance matching section design with coaxial differential feeding. It effectively suppresses aperture edge diffraction and metal edge scattering, avoids high-frequency pattern distortion, and achieves stable radiation performance with a gain ≥5dBi across the entire 6GHz-50GHz band, solving the problem of high-frequency band performance degradation of conventional Vivaldi antennas.

[0020] 4. The overall structure of this invention adopts an all-metal integrated design, without complex dielectric substrates and multi-layer power supply networks. The processing technology is simple and the cost is low. The overall size is only 47mm×47mm×62mm, which has extremely strong system integration capabilities. It can be directly adapted to various miniaturized microwave and millimeter-wave electronic systems such as high-speed wireless communication, radar detection, and ultra-wideband imaging, and has extremely high engineering application value. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural schematic diagram of the compact ultrawideband dual-polarized quad-ridge Vivaldi antenna described in an embodiment of the present invention; Figure 2 This is a front view of the antenna described in an embodiment of the present invention; Figure 3 This is a top view of the antenna described in an embodiment of the present invention; Figure 4 This is a simulation curve of the voltage standing wave ratio (VSWR) of the two polarization ports of the antenna described in this embodiment of the invention. Figure 5 This is a simulation curve of the isolation between the two polarization ports of the antenna described in an embodiment of the present invention; Figure 6 This is a simulation curve of the actual gain of the antenna described in an embodiment of the present invention; Figure 7 The normalized radiation patterns of the antenna described in the embodiments of the present invention at typical frequency points are: (a) 6 GHz, (b) 18 GHz, (c) 26.5 GHz, and (d) 50 GHz.

[0022] In the figure: 1-Radiating body, 2-Polarized radiation pair, 3-Spine-shaped radiation arm, 4-Feed throat, 5-Groove structure, 6-Coaxial feed structure, 7-Base, 8-U-shaped backing cavity. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below through specific embodiments and with reference to the accompanying drawings: This embodiment provides a compact ultra-wideband dual-polarized quad-ridge Vivaldi antenna, whose three-dimensional structure is as follows: Figure 1 As shown, the overall dimensions are 47mm×47mm×62mm, the operating frequency band covers 6GHz-50GHz, and it can simultaneously achieve independent radiation with two orthogonal polarizations, horizontal and vertical.

[0024] like Figures 1-3 As shown, the core structure of the antenna in this embodiment includes a radiating body 1, two sets of orthogonally arranged coaxial feed structures 6, and a base 7. All structures are integrally formed from metal materials and silver-plated on the surface to improve high-frequency conductivity and oxidation resistance.

[0025] The radiating body 1 is the core radiating element of the antenna, which includes two sets of polarized radiating pairs 2. The two sets of polarized radiating pairs 2 are arranged in a 90° orthogonal cross in space, forming a four-ridge radiating structure. Each set of polarized radiating pairs 2 includes two symmetrically arranged ridge-shaped radiating arms 3. The feed ends of the two ridge-shaped radiating arms 3 in the same set are arranged opposite each other, and the radiating port ends are opened outward. A gradually widening groove line is formed between the two arms from the feed end to the radiating port end. The narrow slit at the feed end of the gradually widening groove line is the feed throat 4 of the antenna, which serves as the coupling feed area for radio frequency signals.

[0026] In this embodiment, the outer contour of the ridge-shaped radiating arm 3 is defined using a modified exponential gradient curve, expressed as: ; The preferred parameters for this embodiment are: =0.5mm (initial half-slot width of the feed throat). =0.07 (exponential growth rate); where, Antenna axial position The vertical distance from the edge of the ridge-shaped radiating arm 3 to the central axis of the antenna; The axial coordinate of the antenna, with a value range of 0 ≤ ≤62mm, where 62mm is the total axial length of the radiating body; This is a low-frequency aperture enhancement linear term used to improve aperture radiation efficiency in the low-frequency band and optimize impedance matching at the 6GHz low-frequency end.

[0027] In this embodiment, a set of slotted structures 5 are provided on the edge of the radiating port of the ridge-shaped radiating arm 3. The slotting direction is parallel to the antenna axis, the slotting depth is 5mm, and the width is 1mm. This is used to suppress electromagnetic edge diffraction of the radiating port surface and optimize the symmetry of the radiation pattern in the high-frequency band. The metal layer thickness of the radiating body 1 is 3mm, and the metal edges of all ridge-shaped radiating arms 3 are chamfered at 45° with a chamfer width of 0.4mm. This effectively suppresses electromagnetic scattering of the metal edges and reduces high-frequency signal interference.

[0028] In this embodiment, two sets of coaxial feed structures 6 correspond one-to-one with two sets of polarization radiation pairs 2, and are used to independently feed two orthogonal polarization channels. The coaxial feed structure 6 adopts a 2.4mm RF coaxial connector with a characteristic impedance of 50Ω. Its outer conductor is welded and fixed to the feed end of the ridge radiation arm 3 below the corresponding radiation pair and electrically connected. Its inner conductor passes upward through the feed throat 4 and is welded and fixed to the feed end of the ridge radiation arm 3 above the corresponding radiation pair and electrically connected, forming a differential feed structure. The end of the inner conductor is provided with an impedance matching section with a length of 5.5mm. By adjusting the diameter of the matching section, a smooth impedance transformation of the 6GHz-850GHz full frequency band is achieved, reducing signal reflection.

[0029] In this embodiment, the base 7 is disposed at the bottom of the feed end of the radiating body 1. It is used for the fixed installation and performance optimization of the antenna. Two sets of orthogonally arranged U-shaped backing cavities 8 are provided on the base, and the two sets of U-shaped backing cavities 8 correspond one-to-one with the two sets of polarized radiation pairs 2. The opening of the U-shaped backing cavity 8 faces the radiation port end of the radiating body 1. The groove depth is 19mm and the groove width matches the width of the feed throat 4 of the corresponding radiation pair. The two side walls of the cavity are welded and fixed to the bottom of the feed end of the two ridge-shaped radiation arms 3 of the corresponding radiation pair and electrically connected. The current distribution of the feed end is constrained by the cavity structure, which improves the impedance matching in the low-frequency band, suppresses back radiation, and improves the isolation between orthogonal polarization channels.

[0030] To verify the antenna performance of this embodiment, a full-wave simulation was performed using electromagnetic simulation software. The simulation results are as follows: 1. Impedance matching performance: such as Figure 4 As shown, the voltage standing wave ratio (VSWR) of both polarization ports is ≤2.0 in the full frequency band of 6GHz-50GHz, which meets the impedance matching requirements of high-performance RF systems. More than 89% of the incident power can be effectively transmitted to the radiating unit, and the response curves of the two ports are highly overlapping, which verifies the symmetry and electrical balance of the dual-polarization structure.

[0031] 2. Port isolation performance: such as Figure 5 As shown, in the 6GHz-36GHz frequency band, the isolation between the two polarization ports is ≥20dB, and the peak isolation can reach -35dB near the 10GHz and 19GHz frequencies; in the 36GHz-50GHz high-frequency band, the isolation is still ≥15dB, which fully suppresses crosstalk between orthogonal polarization channels and ensures the integrity of dual-polarization signals.

[0032] 3. Gain performance: such as Figure 6 As shown, within the full frequency band of 6GHz-50GHz, the actual gain of the antenna is ≥5dBi. The gain increases steadily with frequency, reaching a peak of 10.3dBi at 37.5GHz. It only decreases slightly at the edge of the 50GHz high-frequency band, but still remains above 4.8dBi, achieving stable gain performance across the entire frequency band.

[0033] 4. Radiation pattern performance: such as Figure 7 As shown, at four typical frequency points—6 GHz, 18 GHz, 26.5 GHz, and 50 GHz—the antenna's radiation pattern exhibits good end-fire characteristics and symmetry, with no obvious distortion. The 3 dB beamwidth shows a smooth narrowing trend with increasing frequency, being 93.3° at 6 GHz, 54° at 18 GHz, 50.4° at 26.5 GHz, and 24.3° at 50 GHz, thus balancing the wide-angle coverage of the low-frequency band with the high directivity requirements of the millimeter-wave high-frequency band.

[0034] The simulation results above fully verify the technical effect of the present invention. Under a compact structure, it achieves excellent electrical and radiation performance in the ultra-wide frequency band of 6GHz-50GHz, and solves the core technical pain points of the prior art.

[0035] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A compact ultra-wideband dual-polarized quad-ridge Vivaldi antenna, comprising a radiating body, two sets of orthogonally arranged coaxial feed structures, and a base, characterized in that: The radiating body includes two sets of polarized radiating pairs, which are arranged in a 90° orthogonal cross in space to form a four-ridge radiating structure. Each set of polarized radiating pairs includes two symmetrically arranged ridge-shaped radiating arms. The feed ends of the two ridge-shaped radiating arms in the same set are arranged opposite each other, and the radiating ports open outward. A gradually widening groove line is formed between the two arms from the feed end to the radiating port end, and the narrow slot at the feed end of the gradually widening groove line is the feed throat of the antenna. The two sets of coaxial feed structures correspond one-to-one with the two sets of polarization radiation pairs. The outer conductor of the coaxial feed structure is electrically connected to the feed end of any ridge-shaped radiation arm in the corresponding polarization radiation pair, and its inner conductor passes through the feed throat and is electrically connected to the feed end of the other ridge-shaped radiation arm in the corresponding polarization radiation pair, thus forming a differential feed structure. The base is located at the bottom of the feed end of the radiating body. Two sets of orthogonally arranged U-shaped backing cavities are provided on the base. The two sets of U-shaped backing cavities correspond one-to-one with the two sets of polarized radiation pairs. The openings of the U-shaped backing cavities face the radiation port end of the radiating body. The two side walls of the cavities are fixed and electrically connected to the bottom of the feed end of the two ridge-shaped radiation arms of the corresponding polarized radiation pairs.

2. The compact ultra-wideband dual-polarized quad-ridged Vivaldi antenna according to claim 1, characterized in that, The outer contour of the ridge-shaped radial arm is defined using a modified exponential gradient curve, the expression of which is: ； In the formula, Antenna axial position The vertical distance from the edge of the ridge-shaped radiating arm to the central axis of the antenna; This is the initial half-slot width of the feed throat; It is an exponential growth rate and satisfies ; The axial coordinate of the antenna has a range of values. , The total axial length of the radiating body is given. The maximum half-width of the antenna's radiating port; This is the low-frequency aperture enhancement linear term.

3. A compact ultra-wideband dual-polarized quad-ridged Vivaldi antenna according to claim 1, characterized in that, The ridge-shaped radiating arm has at least one set of slotted structures at its radiating port edge, and the slotting direction of the slotted structures is parallel to the antenna axis.

4. A compact ultra-wideband dual-polarized four-ridged Vivaldi antenna according to claim 1, characterized in that, The metal layer of the radiating body is 3mm thick, and the metal edges of all the ridge-shaped radiating arms are chamfered at 45° with a chamfer width of 0.4mm.

5. A compact ultra-wideband dual-polarized four-ridged Vivaldi antenna according to claim 1, characterized in that, The coaxial feed structure uses a 2.4mm RF coaxial connector. The inner conductor of the coaxial feed structure is provided with an impedance matching section with a length of 5.5mm, and the end of the impedance matching section is welded and fixed to the feed end of the ridge-shaped radiating arm.

6. A compact ultra-wideband dual-polarized quad-ridged Vivaldi antenna according to claim 1, characterized in that, The groove depth of the U-shaped backing cavity is 19mm, and the groove width matches the width of the feed throat of the corresponding radiation pair.

7. A compact ultra-wideband dual-polarized quad-ridged Vivaldi antenna according to claim 1, characterized in that, The antenna has overall dimensions of 47mm×47mm×62mm and operates in the 6GHz-50GHz frequency band.

8. A compact ultra-wideband dual-polarized quad-ridged Vivaldi antenna according to claim 7, characterized in that, The port isolation between the two coaxial feed structures of the antenna is ≥20dB in the 6GHz-36GHz frequency band and ≥15dB in the 36GHz-50GHz frequency band.

9. A compact ultra-wideband dual-polarized quad-ridged Vivaldi antenna according to claim 7, characterized in that, The antenna has a voltage standing wave ratio (VSWR) ≤ 2.0 and an actual gain ≥ 5 dBi across the entire 6 GHz-50 GHz frequency band, with a peak actual gain ≥ 10 dBi at the 37.5 GHz frequency point.

10. A compact ultra-wideband dual-polarized quad-ridged Vivaldi antenna according to claim 7, characterized in that, The 3dB beamwidth of the antenna shows a smooth narrowing trend as the operating frequency increases, with a 3dB beamwidth of 93.3° at the 6GHz frequency point and 24.3° at the 50GHz frequency point.

Images