An ultra-wideband dual-ridged horn antenna loaded with a slotted reflector

Abstract

The application relates to the technical field of antennas, in particular to a kind of ultra-wideband double-ridge horn antenna loaded with slotted reflection cavity, which comprises a feed coaxial, a reflection cavity outer wall, an E-plane metal wall, an H-plane metal wall, an ellipsoidal dielectric lens, a tapered feed balun, a ridge structure, a slotted reflection cavity and a corrugated structure.The horn-shaped radiation structure is formed by the ridge structure, the E-plane metal wall and the H-plane metal wall, and the tapered feed balun is used to realize impedance conversion and wideband matching from the coaxial line to the ridge structure.In addition, the corrugated structure is arranged near the antenna aperture surface to suppress unbalanced surface current, and then the ellipsoidal dielectric lens is loaded to correct the spherical wave front to quasi-plane wave, thereby improving the antenna gain and aperture efficiency.It has been verified that the application suppresses spurious resonance through the slotted reflection cavity, realizes good impedance matching in the ultra-wideband, suppresses unbalanced surface current through the corrugated structure, and realizes stable radiation pattern in the full frequency band.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and more specifically to an ultra-wideband double-ridged horn antenna with a slotted reflector. Background Technology

[0002] Ultra-wideband (UWB) technology, as one of the key technologies in modern wireless communication, radar detection, and electromagnetic testing, has an extremely wide spectrum bandwidth and has been widely used in UWB wireless communication, through-wall radar, electromagnetic compatibility testing, electromagnetic pulse radiation sources, and microwave imaging systems.

[0003] In antenna design, horn antennas are widely used due to their simple structure, high gain, and good radiation directivity. Among them, the double-ridged TEM horn antenna improves the high-frequency radiation characteristics of traditional TEM antennas in terms of ultra-wideband performance by introducing a double-ridged structure into the traditional TEM horn antenna. The double-ridged structure allows the antenna to maintain good impedance matching in the low-frequency band while maintaining quasi-TEM mode transmission in the high-frequency band, reducing high-order mode excitation, and achieving excellent ultra-wideband radiation characteristics.

[0004] However, existing double-ridged horn antennas still have some technical problems: in extremely wide bandwidths (such as 2-100 GHz), impedance matching is often difficult in the low-frequency band due to the small distance between the ridges, resulting in a high standing wave ratio; the gain in the low-frequency band is relatively low, mainly due to the uneven phase distribution of the aperture field, leading to low far-field synthesis efficiency; in the high-frequency band, problems such as main lobe splitting, concavity, sidelobe enlargement, and pattern asymmetry are prone to occur, affecting radiation characteristics and system detection accuracy. Traditional feeding methods are difficult to achieve full-band matching and feeding balance in the ultra-wideband range, and aperture edge diffraction and surface wave propagation also affect radiation performance. Summary of the Invention

[0005] The purpose of this invention is to provide an ultra-wideband double-ridged horn antenna with a slotted reflector, which aims to solve the technical problems of existing ultra-wideband double-ridged horn antennas in the 2-100GHz frequency band, such as difficulty in low-frequency matching, low low-frequency gain, and unstable high-frequency radiation pattern.

[0006] To achieve the above objectives, the present invention provides an ultra-wideband dual-ridge horn antenna with a slotted reflector, comprising a coaxial feed, an outer wall of the reflector, an E-plane metal wall, an H-plane metal wall, an ellipsoidal dielectric lens, a conical feed balun, a ridge structure, a slotted reflector, and a corrugated structure. The outer wall of the reflector is sequentially connected to the E-plane metal wall and the H-plane metal wall to form a hollow structure.

[0007] The ellipsoidal dielectric lens is disposed at the ends of the E-plane metal wall and the H-plane metal wall, i.e., at the antenna aperture surface, on the side away from the outer wall of the reflective cavity;

[0008] The ridge structure includes a symmetrically arranged upper ridge plate and a lower ridge plate, and its shape gradually expands along the antenna axis in a curved manner.

[0009] The conical feed balun is connected to the tail of the lower ridge plate, and its thin end is connected to the inner conductor of the feed coaxially.

[0010] The slotted reflective cavity is disposed inside the outer wall of the reflective cavity; the corrugated structure is disposed on the inner side of the E-plane metal wall and the H-plane metal wall located near the antenna aperture plane.

[0011] The outer wall of the reflective cavity is provided with a through hole, one end of the feeding coaxial cable passes through the outer wall of the reflective cavity, and the outer conductor of the feeding coaxial cable is connected to the outer wall of the reflective cavity.

[0012] The characteristic impedance Z(y) of the tapered feed balun is determined by the parallel two-conductor transmission line model, and its expression is as follows:

[0013]

[0014] Where h(y) is the distance between the two conductor plates in the conical feed balun, W(y) is the width of the conductor plate, and y is the position coordinate along the antenna axis.

[0015] The characteristic impedance Z(y) of the tapered feed balun is determined by the parallel two-conductor transmission line model, and its expression is as follows:

[0016]

[0017] Where h(y) is the distance between the two conductor plates in the conical feed balun, W(y) is the width of the conductor plate, and y is the position coordinate along the antenna axis.

[0018] The ellipsoidal dielectric lens has an elliptical gradient at the top and its bottom is flush with the top of the E-plane metal wall and the H-plane metal wall. The interior of the ellipsoidal dielectric lens is completely filled with a dielectric material, which is cross-linked polystyrene with a dielectric constant of 2.5.

[0019] The ultra-wideband double-ridged horn antenna with a slotted reflector cavity operates at a frequency of 10GHz-100GHz and has overall dimensions of 0.33λ1×0.47λ1×0.5λ1, where λ1 is the wavelength corresponding to an operating frequency of 10GHz.

[0020] This invention provides an ultra-wideband dual-ridge horn antenna with a slotted reflector cavity, comprising a coaxial feed, an outer wall of the reflector cavity, an E-plane metal wall, an H-plane metal wall, an ellipsoidal dielectric lens, a conical feed balun, a ridge structure, a slotted reflector cavity, and a corrugated structure. The horn-shaped radiating structure, composed of the ridge structure, the E-plane metal wall, and the H-plane metal wall, utilizes a conical feed balun to achieve impedance conversion and broadband matching from the coaxial feed to the ridge structure. In use, electromagnetic signals are fed into the antenna through the coaxial feed, transitioned through the conical feed balun, and then radiated outwards along the ridge structure. Furthermore, a corrugated structure is placed near the antenna aperture to suppress unbalanced surface currents caused by asymmetry in the feed structure. Finally, an ellipsoidal dielectric lens is used to correct the spherical wavefront into a quasi-plane wave, improving antenna gain and aperture efficiency. Verification has shown that this invention achieves good impedance matching over an ultra-wide bandwidth by suppressing parasitic resonance through a slotted reflective cavity; it achieves a stable radiation pattern across the entire frequency band by suppressing unbalanced surface current through a corrugated structure; and it improves antenna gain and high-frequency radiation pattern by loading an ellipsoidal dielectric lens. Attached Figure Description

[0021] 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 these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of the ultra-wideband double-ridged horn antenna with a slotted reflector cavity according to a specific embodiment of the present invention.

[0023] Figure 2 This is a side view of an ultra-wideband dual-ridge horn antenna with a slotted reflector cavity in a specific embodiment of the present invention.

[0024] Figure 3 This is a top view of an ultra-wideband double-ridged horn antenna with a slotted reflector cavity in a specific embodiment of the present invention.

[0025] Figure 4 This is a front view of an ultra-wideband dual-ridge horn antenna with a slotted reflector cavity in a specific embodiment of the present invention.

[0026] Figure 5 This is a schematic cross-sectional view of the ultra-wideband double-ridged horn antenna with a slotted reflector cavity in an embodiment of the present invention.

[0027] Figure 6 This is a longitudinal cross-sectional schematic diagram of an ultra-wideband double-ridged horn antenna with a slotted reflector cavity in an embodiment of the present invention.

[0028] Figure 7This is a VSWR simulation result diagram of the ultra-wideband double-ridged horn antenna with a slotted reflector cavity as described in the embodiment of the present invention;

[0029] Figure 8 This is a simulation result of the gain curve of the ultra-wideband double-ridged horn antenna with a slotted reflector cavity as described in an embodiment of the present invention.

[0030] Figure 9 This is the simulated radiation pattern (E-plane) of the ultra-wideband double-ridged horn antenna with a slotted reflector cavity as described in this embodiment of the invention.

[0031] Figure 10 This is a simulated radiation pattern (H-plane) of the ultra-wideband double-ridged horn antenna with a slotted reflector cavity as described in an embodiment of the present invention.

[0032] 1-Coaxial feed, 2-Outer wall of the reflective cavity, 3-E-plane metal wall, 4-H-plane metal wall, 5-Ellipsoidal dielectric lens, 6-Conical feed balun, 7-Ridge structure, 8-Slotted reflective cavity, 9-Corrugated structure. Detailed Implementation

[0033] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0034] This invention provides an ultra-wideband dual-ridge horn antenna with a slotted reflector, comprising a coaxial feed, an outer wall of the reflector, an E-plane metal wall, an H-plane metal wall, an ellipsoidal dielectric lens, a conical feed balun, a ridge structure, a slotted reflector, and a corrugated structure. The outer wall of the reflector is sequentially connected to the E-plane metal wall and the H-plane metal wall to form a hollow structure.

[0035] The ellipsoidal dielectric lens is disposed at the ends of the E-plane metal wall and the H-plane metal wall, i.e., at the antenna aperture surface, on the side away from the outer wall of the reflective cavity;

[0036] The outer wall of the reflector cavity is sequentially connected to the E-plane metal wall and the H-plane metal wall to form the main radiating structure of the antenna. The outer wall of the reflector cavity serves as a closed structure at the tail of the antenna, used to confine electromagnetic waves and prevent energy leakage backward.

[0037] The ridge structure includes a symmetrically arranged upper ridge plate and a lower ridge plate, and its shape gradually expands along the antenna axis, so that the antenna impedance transitions smoothly to the free space impedance.

[0038] The tapered feed balun is connected to the tail of the lower ridge plate, and the thin end is connected to the inner conductor of the feed coaxial line. The tapered feed balun achieves a smooth transition from the coaxial line impedance (50Ω) to the antenna input impedance, increases the antenna bandwidth, and realizes ultra-wideband.

[0039] The slotted reflective cavity is disposed within the outer wall of the reflective cavity; by setting a metal groove at the bottom of the reflective cavity, the equivalent reactance of the reflective cavity is adjusted, effectively suppressing parasitic resonance modes and improving impedance matching performance in the high-frequency band.

[0040] The corrugated structure is provided on the inner side of the E-plane and H-plane metal walls located near the antenna aperture plane. The corrugated structure forms a high surface impedance, blocks the propagation path of unbalanced surface currents, and restores the symmetry of the radiation pattern.

[0041] The outer wall of the reflective cavity is provided with a through hole, one end of the feeding coaxial cable passes through the outer wall of the reflective cavity, and the outer conductor of the feeding coaxial cable is connected to the outer wall of the reflective cavity.

[0042] The characteristic impedance Z(y) of the tapered-feed balun is determined by the parallel two-conductor transmission line model, and the expression is as follows:

[0043]

[0044] h(y) is the distance between the two conductor plates in the conical feed balun, W(y) is the width of the conductor plate, and y is the position coordinate along the antenna axis.

[0045] The characteristic impedance Z(y) of the tapered feed balun is determined by the parallel two-conductor transmission line model, and its expression is as follows:

[0046]

[0047] h(y) is the distance between the two conductor plates in the conical feed balun, W(y) is the width of the conductor plate, and y is the position coordinate along the antenna axis.

[0048] The top of the ellipsoidal dielectric lens is elliptical with a gradual elliptical transition, and the bottom of the ellipsoidal dielectric lens is flush with the top of the E-plane metal wall and the H-plane metal wall. The interior of the ellipsoidal dielectric lens is completely filled with a dielectric material, which is cross-linked polystyrene with a dielectric constant of 2.5. This solves the aperture phase error problem, enables the antenna to operate with ultra-wideband high gain, guides electromagnetic waves to radiate outward, corrects the antenna aperture phase error, improves the radiation pattern at high frequencies, and increases the antenna gain.

[0049] The ultra-wideband double-ridged horn antenna with a slotted reflector cavity operates at a frequency of 10GHz-100GHz and has overall dimensions of 0.33λ1×0.47λ1×0.5λ1, where λ1 is the wavelength corresponding to an operating frequency of 10GHz.

[0050] Specifically, the ultra-wideband dual-ridge horn antenna with a slotted reflector described in this invention comprises a pair of horn-shaped radiating structures consisting of a ridge structure and E-plane and H-plane metal walls. A tapered feed balun is used to achieve impedance conversion and broadband matching from the coaxial line to the ridge structure. In use, the electromagnetic signal is fed into the antenna through the coaxial feed, transitions through the tapered feed balun, and then radiates outwards along the ridge structure. By setting a slotted reflector on the inner wall at the bottom of the outer wall of the reflector, the resonance conditions of the parasitic resonance mode are disrupted, eliminating its degrading effect on the input impedance. By setting a corrugated structure near the antenna aperture, the unbalanced surface current caused by the asymmetry of the feed structure is suppressed, eliminating beam deflection and splitting at high frequencies. By loading an ellipsoidal dielectric lens, the spherical wavefront is corrected to a quasi-plane wave, improving the antenna gain and aperture efficiency.

[0051] For further details, please refer to Figures 1 to 10 The present invention will be further illustrated with specific embodiments:

[0052] As attached Figures 1 to 6 As shown, this embodiment provides an ultra-wideband dual-ridge horn antenna with a slotted reflector cavity, including a feeding coaxial cable 1, a reflector cavity outer wall 2, an E-plane metal wall 3, an H-plane metal wall 4, an ellipsoidal dielectric lens 5, a conical feeding balun 6, a ridge structure 7, a slotted reflector cavity 8, and a corrugated structure 9. The reflector cavity outer wall 2 is sequentially connected to the E-plane metal wall 3 and the H-plane metal wall 4 to form the main radiating structure. The conical feeding balun 6 is located inside the antenna, with its wide end connected to the ridge structure 7 and its narrow end connected to the inner conductor of the feeding coaxial cable 1. The slotted reflector cavity 8 is formed on the bottom inner wall of the reflector cavity outer wall 2. The corrugated structure 9 is disposed on the E-plane metal wall 3 and the H-plane metal wall 4 near the antenna aperture plane. The ellipsoidal dielectric lens 5 is disposed at the antenna aperture plane.

[0053] In this embodiment, the antenna operates in the frequency range of 10GHz-100GHz. The antenna has a height of 0.5λ1, a length of 0.47λ1, and a width of 0.33λ1, where λ1 is the wavelength (approximately 30mm) corresponding to the operating frequency of 10GHz. The overall dimensions are approximately 15mm × 14.1mm × 9.9mm.

[0054] The outer wall 2 of the reflective cavity has multiple metal grooves forming a slotted reflective cavity 8. The width and depth of the grooves are optimized and determined according to the target resonant frequency to suppress parasitic resonance.

[0055] The tapered feed balun 6 adopts a parallel double conductor gradient structure. The distance hy between the two conductor plates and the width Wy of the conductor plates change along the axial direction according to the impedance gradient law, ensuring a smooth transition from the 50Ω coaxial line impedance to the antenna input impedance.

[0056] The ridge structure 7 adopts an exponential curve or elliptical curve to gradually open, with a small ridge spacing at the feed end and a large ridge spacing at the aperture end, to achieve a smooth transition to free space impedance (377Ω).

[0057] The ellipsoidal dielectric lens 5 is made of cross-linked polystyrene (XCPS) material with a dielectric constant of 2.5 and a loss tangent of 0.0005. The overall height of the lens is flush with the top of the metal wall 3 on the E-plane and the metal wall 4 on the H-plane, and its interior is completely filled with dielectric material.

[0058] The corrugated structure 9 is located near the aperture surface. The depth and period of the corrugations are optimized and determined according to the operating frequency band, and are used to form high surface impedance on unbalanced current paths.

[0059] As attached Figure 7 As shown in the attached figure, the VSWR simulation results of the ultra-wideband double-ridged horn antenna with a slotted reflector described in this embodiment are presented. It can be seen from the figure that the VSWR is less than 2.5 in the 10GHz-100GHz frequency band, meeting the antenna VSWR requirements. In contrast, the antenna without a slotted reflector exhibits significant matching degradation in the 40GHz-100GHz frequency band, verifying the effectiveness of the slotted reflector in suppressing parasitic resonances.

[0060] The accompanying figures show a comparison of the radiation patterns of the antenna described in this embodiment at 50 GHz. As can be seen from the figures, the antenna without the corrugated structure exhibits significant asymmetry and beam skew in its radiation pattern; while with the corrugated structure, the antenna's E-plane and H-plane radiation patterns show good symmetry, and the main lobe is stable along the line of sight, verifying the effectiveness of the corrugated structure in suppressing unbalanced surface currents.

[0061] The attached figures show the near-field electric field distribution of the antenna described in this embodiment at 60 GHz before and after loading the ellipsoidal dielectric lens. As can be seen from the figures, without the lens, the aperture electric field exhibits a spherical wave distribution; after loading the lens, the aperture electric field is corrected to a quasi-plane wave distribution, verifying the phase compensation effect of the lens.

[0062] As attached Figure 8 As shown in the attached figure, the gain of the antenna described in this embodiment varies with frequency under three different configurations. It can be seen from the figure that after loading the ellipsoidal dielectric lens, the antenna gain is significantly improved throughout the 10GHz-100GHz frequency band, especially in the high-frequency range, where the gain value is higher and the curve is smoother.

[0063] As attached Figure 9 and Figure 10 As shown in the attached figure, the normalized E-plane and H-plane radiation patterns of the antenna described in this embodiment are given throughout the entire operating frequency band. It can be seen from the figure that the main lobe maintains good line-of-sight symmetry across the entire 10GHz-100GHz frequency band, with no beam skew or splitting, and the sidelobe and back lobe levels are effectively suppressed.

[0064] In summary, the overall dimensions of the ultra-wideband double-ridged horn antenna with a slotted reflector cavity in this embodiment are 0.33λ1×0.47λ1×0.5λ1 (λ1 is the wavelength corresponding to the operating frequency of 10GHz). It features a compact size, high gain, and a bandwidth of 10GHz-100GHz, exhibiting excellent ultra-wideband characteristics and stable radiation characteristics, thus meeting the antenna requirements of millimeter-wave detection and electronic countermeasures systems. The antenna can be manufactured using precision metal processing or 3D printing technology, resulting in a stable structure and good consistency.

[0065] In summary, compared with the prior art, the beneficial effects of the present invention are as follows:

[0066] This invention provides an ultra-wideband dual-ridge horn antenna with a slotted reflector cavity. By setting a slotted structure on the inner wall of the bottom of the reflector cavity, the equivalent reactance of the reflector cavity is adjusted, effectively suppressing or eliminating parasitic resonance modes that are difficult to avoid in traditional smooth reflector cavities, and achieving good impedance matching in the ultra-wideband. By setting a tapered feed balun, a smooth transition from coaxial line impedance to antenna input impedance is achieved. Combined with the suppression of unbalanced surface current by the corrugated structure, the influence of feed structure asymmetry is effectively compensated, eliminating beam skew and splitting at high frequencies, and ensuring the symmetry and stability of the radiation pattern in the entire frequency band.

[0067] Furthermore, the loaded ellipsoidal dielectric lens performs phase compensation on the antenna aperture field, correcting spherical or cylindrical waves into quasi-plane waves, which significantly improves the antenna's aperture efficiency and high-frequency gain.

[0068] Furthermore, the corrugated structure is set on the E-plane metal wall and / or H-plane metal wall near the antenna aperture surface. By forming a high surface impedance, it effectively blocks the unbalanced current path and further improves the symmetry of the radiation pattern.

[0069] Furthermore, the ellipsoidal dielectric lens uses cross-linked polystyrene (XCPS) material, which has the characteristics of stable dielectric constant and low loss tangent, ensuring the stable performance of the antenna in the 10GHz-100GHz ultra-wideband.

[0070] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. An ultra-wideband double-ridged horn antenna with a slotted reflector cavity, characterized in that, It includes a coaxial feed, an outer wall of the reflective cavity, an E-plane metal wall, an H-plane metal wall, an ellipsoidal dielectric lens, a conical feed balun, a ridge structure, a slotted reflective cavity, and a corrugated structure. The outer wall of the reflective cavity is sequentially connected to the E-plane metal wall and the H-plane metal wall to form a hollow structure. The ellipsoidal dielectric lens is disposed at the ends of the E-plane metal wall and the H-plane metal wall, i.e., at the antenna aperture surface, on the side away from the outer wall of the reflective cavity; The ridge structure includes a symmetrically arranged upper ridge plate and a lower ridge plate, and its shape gradually expands along the antenna axis in a curved manner. The conical feed balun is connected to the tail of the lower ridge plate, and its thin end is connected to the inner conductor of the feed coaxially. The slotted reflective cavity is disposed inside the outer wall of the reflective cavity; the corrugated structure is disposed on the inner side of the E-plane metal wall and the H-plane metal wall located near the antenna aperture plane.

2. The ultra-wideband double-ridged horn antenna with a slotted reflector cavity as described in claim 1, characterized in that, The outer wall of the reflective cavity is provided with a through hole, one end of the feeding coaxial cable passes through the outer wall of the reflective cavity, and the outer conductor of the feeding coaxial cable is connected to the outer wall of the reflective cavity.

3. The ultra-wideband double-ridged horn antenna with a slotted reflector cavity as described in claim 2, characterized in that, The characteristic impedance Z(y) of the tapered-feed balun is determined by the parallel two-conductor transmission line model, and the expression is as follows: Where h(y) is the distance between the two conductor plates in the conical feed balun, W(y) is the width of the conductor plate, and y is the position coordinate along the antenna axis.

4. The ultra-wideband double-ridged horn antenna with a slotted reflector cavity as described in claim 3, characterized in that, The top of the ellipsoidal dielectric lens is elliptical with a gradual transition, and the bottom of the ellipsoidal dielectric lens is flush with the top of the E-plane metal wall and the H-plane metal wall; the interior of the ellipsoidal dielectric lens is completely filled with a dielectric material, which is cross-linked polystyrene with a dielectric constant of 2.

5.

5. The ultra-wideband double-ridged horn antenna with a slotted reflector cavity as described in claim 4, characterized in that, The ultra-wideband double-ridged horn antenna with a slotted reflector cavity operates at a frequency of 10GHz-100GHz and has overall dimensions of 0.33λ1×0.47λ1×0.5λ1, where λ1 is the wavelength corresponding to an operating frequency of 10GHz.

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