A common-aperture ultrawideband end-fire antenna embedded in a metal carrier

Abstract

An ultra-wideband end-fire antenna with a common aperture embedded in a metal carrier includes a metal cavity with a coaxial cable compartment on one side. A radiator module is connected to the bottom of the metal cavity via a radiator fixing slot. The radiator module includes a common aperture antenna substrate. A low-frequency radiator is printed on the side of the common aperture antenna substrate closer to the coaxial cable compartment, and a high-frequency radiator is printed on the side farther from the coaxial cable compartment. This invention utilizes a dual-band antenna in a common aperture design to enhance the channel capacity and anti-fading capability of the communication system. At the same time, by achieving the antenna's carrier conformal characteristics, high isolation, and miniaturization, it enriches the antenna's application scenarios and improves the overall performance of the communication system.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, specifically relating to a common-aperture ultra-wideband end-fire antenna embedded in a metal carrier. Background Technology

[0002] Ultra-wideband (UWB) end-fire antennas are widely used in various tasks, such as target detection, wireless communication, positioning, and target navigation, due to their advantages of wide bandwidth, high transmission rate, strong anti-interference capability, and low intercept rate. These applications require embedding the antenna in a complex metal platform, meaning the antenna will be surrounded by a metallic environment. The metal surrounding the antenna has a significant impact on its electrical performance, especially for antennas used to achieve end-fire performance. The surrounding metal acts as a shield for electromagnetic waves, preventing effective beam coverage in the end-fire direction. Therefore, the design of UWB end-fire antennas based on metallic platforms still faces significant challenges.

[0003] Driven by aerodynamic requirements, antennas mounted on certain aircraft possess characteristics such as low profile and easy conformal installation. Conformal antennas can achieve navigation, communication, and positioning functions of traditional antennas without affecting the shape and aerodynamic characteristics of the carrier. However, since different systems have different polarization forms, antennas with vertical polarization often require higher profile heights due to their inherent physical limitations. Therefore, designing vertically polarized antennas with low profile characteristics has become a major challenge in the current research field.

[0004] End-fire antennas, categorized by their radiation patterns, offer advantages such as high directivity and wide bandwidth adaptability. However, high-speed aircraft not only possess large-area metal-covered protective shells but also metal support structures to enhance overall strength, creating a highly complex electromagnetic environment around the antenna. In this environment, the electrical performance of most end-fire antennas deteriorates rapidly when brought close to large metal surfaces.

[0005] Currently, most research focuses on broadband end-fire antennas that achieve good end-to-end radiation beams under the premise of vertical polarization and low profile. Among this small portion of broadband end-fire antennas, there are end-fire antennas with high-gain radiation characteristics achieved through a relatively long longitudinal structure, but their practicality is poor. The design of broadband end-fire antennas embedded in metallic platforms using embedded conformal mounting methods is even rarer. Moreover, due to the diversity and complexity of the carrier environment, research on corresponding carrier conformal antenna technologies is fraught with uncertainty and challenges.

[0006] Patent application CN114335986A discloses a low-profile ultra-wideband end-fire antenna, including a waveguide structure body, a metal ridge and a ceramic body; the ceramic material adopted in this patent application is inserted into the interior of the waveguide structure body, and the inserted part is a structure with a gradually changing height, obtaining broadband matching, and the practicability is poor. Summary of the Invention

[0007] In order to overcome the deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to propose a co-aperture carrier conformal ultra-wideband end-fire antenna, which uses a dual-band antenna in the co-aperture design to enhance the channel capacity and anti-fading ability of the communication system; at the same time, by realizing the characteristics of antenna carrier conformal, high isolation, miniaturization, etc., to improve the comprehensive performance of the communication system.

[0008] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A co-aperture ultra-wideband end-fire antenna embedded in a metal carrier, including a metal cavity 9, a coaxial line chamber 15 is provided on one side of the metal cavity 9, a radiator module is connected to the bottom of the metal cavity 9, and the radiator module includes a co-aperture antenna substrate 4. A low-frequency radiator 3 is printed on one side of the co-aperture antenna substrate 4 close to the coaxial line chamber 15, and a high-frequency radiator 5 is printed on the side far from the coaxial line chamber 15. A dielectric lens unit 12 is covered on the top of the high-frequency radiator 5, and a low-frequency antenna top-loading substrate 1 is covered above the dielectric lens unit 12 and the metal cavity 9. A triangular strip top-loading structure 2 is printed on the bottom surface of the low-frequency antenna top-loading substrate 1, and the triangular strip top-loading structure 2 is in contact and cooperation with the top of the low-frequency radiator 3; the low-frequency radiator 3 is fed through a low-frequency coaxial feeder line connected to a low-frequency radiator SMA connector flange 1301 in the coaxial line chamber 15, and the high-frequency radiator 5 is fed through a high-frequency coaxial feeder line connected to a high-frequency radiator SMA connector flange 1302 in the coaxial line chamber 15.

[0010] The metal cavity 9 is an inverted trapezoidal cavity with a wide upper mouth and a narrow bottom.

[0011] Both the low-frequency radiator 3 and the high-frequency radiator 5 are made of metal materials.

[0012] An inclined comb-shaped slot line 3-1 is opened above the low-frequency radiator 3, the slot lines are arranged at equal intervals, and the interval is 1.4 mm ± 0.2 mm, and a "Ji" shaped slot line 3-2 is opened at one end of the low-frequency radiator 3 close to the coaxial line chamber 15 for connecting the coaxial line.

[0013] The high-frequency radiator 5 is printed on the antenna substrate 4 along the angled end of the inverted trapezoidal metal cavity 9. A comb-shaped groove line 5-1 is opened above the high-frequency radiator 5, and the comb-shaped groove lines 5-1 are arranged at equal intervals with a spacing of 1.4mm ± 0.2mm. A small hole 5-2 is opened at the bottom of the high-frequency radiator 5 near the low-frequency radiator 3 for connecting the coaxial line.

[0014] The triangular strip top loading structure 2 is composed of several horizontal metal strips of decreasing length forming an acute isosceles triangle structure with an acute apex angle of 30°±2°. The longest horizontal metal strip is 26mm±0.5 mm and the shortest is 3mm±0.5 mm. The spacing between adjacent horizontal metal strips is 1.5mm±0.1 mm.

[0015] The dielectric lens unit 12 consists of two inverted trapezoidal lenses connected side by side. A slot is provided between the two inverted trapezoidal lenses to ensure that the dielectric lens unit 12 does not contact the high-frequency radiator. The inclination angle of the inclined surfaces on both sides of the two inverted trapezoidal lenses is the same as the inclination angle of the side wall of the inverted trapezoidal metal cavity 9, which is 45°±2°.

[0016] The common aperture antenna substrate 4 is connected to the common aperture antenna substrate slot 11 located on the top of the coaxial cable compartment 15 and the bottom of the coaxial cable compartment metal cover plate 10.

[0017] Line clips 6 are respectively provided on both sides of the common aperture antenna substrate slot 11 and on one side wall of the metal cavity 9.

[0018] The metal is silver, copper, or copper plated with silver.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] The antenna structure of this invention is simple. In the small-sized antenna structure, the feed ports of the low-frequency radiator 3 and the high-frequency radiator 5 are located close to the metal base plate, which makes it easier to process and weld. In addition, the half-mode Vivaldi tapered slot antenna designed by using the image theory forms an equal-amplitude and in-phase current with the high-frequency radiator 5, the low-frequency radiator 3 and the metal structure at the bottom of the cavity. At the same time, since only half of the structure is used, the impedance can be halved, and the equivalent input impedance is about 50Ω. This changes the problem that traditional tapered slot antennas need to use a balun for impedance transformation. Good impedance matching can be achieved by directly feeding with a coaxial cable.

[0021] A high-frequency radiator 5 is placed in front of the low-frequency radiator 3. The metal slope of the metal cavity 9 is used to shorten the distance between the radiator and the aperture to achieve a good high-frequency radiation mode. At the same time, the cavity reduces the obstruction of the antenna and enhances the end-fire performance. The split common aperture antenna layout solves the problem of the split lobe of the antenna E-plane and H-plane to a certain extent, so that the antenna has more stable radiation characteristics.

[0022] In addition to adopting a split common-aperture antenna layout, the beamwidth of the high-frequency radiating plate gradually narrows as the frequency increases due to the influence of the carrier environment. In order to reshape the waveform, a dielectric lens unit 12 is loaded to compensate and adjust the phase of the electromagnetic wave. This increases the phase delay difference between each direction and the main radiation direction, thus widening the beam.

[0023] A triangular strip top-loaded structure 2 is added above the low-frequency antenna radiator 3, and the triangular strip top-loaded structure 2 cooperates with the inclined comb-shaped slot line 3-1 on the low-frequency radiator. On the one hand, the inclined comb-shaped slot line 3-1 acts as a resonator, and the top-loaded form forms a parallel plate capacitor with the ground to suppress edge current and improve end-firing effect. On the other hand, the inclined comb-shaped slot line 3-1 extends the current path, which reduces the operating frequency and achieves better impedance matching. Since the lower the cutoff frequency, the larger the electrical size, multiple comb-shaped slot lines 5-1 are opened on the high-frequency radiator 5. The comb-shaped slot lines 5-1 extend the current path and effectively enlarge the electrical size. Under the same size, a lower cutoff frequency can be obtained, that is, the antenna is miniaturized.

[0024] The inverted trapezoidal metal cavity 9 can optimize the impedance matching of the antenna without sacrificing radiation efficiency. The antenna of this invention can be embedded and operated in different metal platform working environments. By reducing metal obstruction, a certain radiation optimization effect is also achieved, ensuring a stable wide beam in the H-plane radiation pattern. The inclined metal walls on both sides not only allow electromagnetic waves to be effectively radiated through reflection, but also have the advantage of high radiation efficiency. After optimization, the inclined angle of the inverted trapezoidal metal cavity is selected as 45°.

[0025] In summary, this invention, based on the tapered slot antenna theory and image theory, effectively improves the port isolation between the dual-band radiators by employing a separate layout for the low-frequency radiator 3 and the high-frequency radiator 5. Furthermore, the high-frequency radiator 5, acting as the guiding structure for the low-frequency radiator, enhances the end-fire performance of the low-frequency antenna, thereby strengthening the anti-interference capability of the communication system. The feed ports of the low-frequency radiator 3 and the high-frequency radiator 5 are positioned close to the metal base plate, facilitating processing and welding. A dielectric lens element 12, functioning as a concave lens, is installed directly above the high-frequency radiator, achieving a stable beamwidth over a wide bandwidth. The inverted trapezoidal metal cavity 9 effectively reduces antenna resonance within the cavity, achieving impedance matching over a wider bandwidth. Therefore, this invention, a common-aperture carrier conformal ultra-wideband antenna, has strong practical application value in increasing the channel capacity and resistance to fading in communication systems, improving overall system performance, and achieving high-performance communication. Attached Figure Description

[0026] Figure 1 This is an overall structural diagram of the antenna unit of the present invention.

[0027] Figure 2 This is a structural diagram of the antenna metal cavity 9 and the coaxial cable compartment 15 of the present invention.

[0028] Figure 3 This is a front view of the antenna metal cavity 9 structure of the present invention.

[0029] Figure 4 This is a structural diagram of the top-loaded substrate 1 of the low-frequency antenna of the present invention.

[0030] Figure 5 This is a structural diagram showing the connection between the top-loaded substrate 1 of the low-frequency antenna and the low-frequency radiator 3 of the present invention.

[0031] Figure 6 This is a structural diagram of the low-frequency radiator 3 and the high-frequency radiator 5 of the antenna of the present invention.

[0032] Figure 7 This is a structural diagram of the metal cover plate 10 for the antenna coaxial cable compartment of the present invention.

[0033] Figure 8 This is a structural diagram of the high-frequency dielectric lens unit 12 of the present invention.

[0034] Figure 9 This is a comparison chart of the simulation results and measured results of the voltage standing wave ratio (VSWR) of the low-frequency antenna of this invention.

[0035] Figure 10 This is a comparison chart of the simulation results and the measured results of the voltage standing wave ratio (VSWR) of the high-frequency antenna of this invention.

[0036] Figure 11 This is a diagram showing the port isolation between the low-frequency antenna and the high-frequency antenna of the present invention.

[0037] Figure 12 This is the elevation radiation pattern of the 2GHz antenna of this invention.

[0038] Figure 13 This is the azimuth radiation pattern of the 2GHz antenna of the present invention.

[0039] Figure 14 This is the elevation radiation pattern of the 4GHz antenna of this invention.

[0040] Figure 15 This is the azimuth radiation pattern of the 4GHz antenna of this invention.

[0041] Figure 16 This is the elevation radiation pattern of the 6GHz antenna of this invention.

[0042] Figure 17 This is the azimuth radiation pattern of the 6GHz antenna of this invention.

[0043] Figure 18It is the elevation radiation pattern of the 8GHz antenna of the present invention.

[0044] Figure 19 It is the azimuth radiation pattern of the 8GHz antenna of the present invention.

[0045] Figure 20 It is the elevation radiation pattern of the 12GHz antenna of the present invention.

[0046] Figure 21 It is the azimuth radiation pattern of the 12GHz antenna of the present invention.

[0047] Figure 22 It is the elevation radiation pattern of the 18GHz antenna of the present invention.

[0048] Figure 23 It is the azimuth radiation pattern of the 18GHz antenna of the present invention.

[0049] In the figure: 1. Low-frequency antenna top-loading substrate; 2. Triangular strip top-loading structure; 3. Low-frequency radiator; 3-1. Inclined comb-shaped slot line; 3-2. "Ji"-shaped slot line; 4. Common-aperture antenna substrate; 5. High-frequency radiator; 5-1. Comb-shaped slot line; 5-2. Small hole; 6. Line clamp structure; 9. Metal cavity; 10. Metal cover plate of coaxial cable compartment; 11. Common-aperture antenna substrate card slot; 12. Dielectric lens unit; 1301. SMA connector flange of low-frequency radiator; 1302. SMA connector flange of high-frequency radiator; 15. Coaxial cable compartment; 16. Radiator fixing card slot. Specific embodiments

[0050] The present invention will be further described in detail below with reference to the accompanying drawings.

[0051] Refer to Figures 1 to 3 , a common-aperture ultra-wideband end-fire antenna embedded in a metal carrier, including a metal cavity 9, a coaxial cable compartment 15 is provided on one side of the metal cavity 9, a radiator module is connected to the bottom of the metal cavity 9 through a radiator fixing card slot 16, the radiator module includes a common-aperture antenna substrate 4, a low-frequency radiator 3 is printed on one side of the common-aperture antenna substrate 4 close to the coaxial cable compartment 15, a high-frequency radiator 5 is printed on the side far from the coaxial cable compartment 15, a dielectric lens unit 12 is covered on the top of the high-frequency radiator 5, a low-frequency antenna top-loading substrate 1 is covered above the dielectric lens unit 12 and the metal cavity 9, a triangular strip top-loading structure 2 is printed on the bottom surface of the low-frequency antenna top-loading substrate 1, and the triangular strip top-loading structure 2 is in contact and cooperation with the top of the low-frequency radiator 3; the low-frequency radiator 3 is fed through a low-frequency coaxial feeder wire connected to the low-frequency radiator SMA connector flange 1301 in the coaxial cable compartment 15, and the high-frequency radiator 5 is fed through a high-frequency coaxial feeder wire connected to the high-frequency radiator SMA connector flange 1302 in the coaxial cable compartment 15.

[0052] See Figure 3 , the metal cavity 9 is an inverted trapezoidal cavity with a wide upper mouth and a narrow bottom.

[0053] Both the low-frequency radiator 3 and the high-frequency radiator 5 are made of metal materials.

[0054] See Figure 6 , an inclined comb-shaped slot line 3-1 is provided above the low-frequency radiator 3, and the slot lines are arranged at equal intervals with a spacing of 1.4 mm ± 0.2 mm. And a "Ji" - shaped slot line 3-2 is provided at one end of the low-frequency radiator 3 near the coaxial line cabin 15 for connecting the coaxial line.

[0055] The high-frequency radiator 5 is printed along the inclined surface angle of the end of the inverted trapezoidal metal cavity 9 on the co-aperture antenna substrate 4. Comb-shaped slot lines 5-1 are provided above the high-frequency radiator 5, and the comb-shaped slot lines 5-1 are arranged at equal intervals with a spacing of 1.4 mm ± 0.2 mm; small holes 5-2 are provided at the bottom of the high-frequency radiator 5 near the position of the low-frequency radiator 3 for connecting the coaxial line.

[0056] See Figure 4 、 Figure 5 , the triangular strip top-loading structure 2 is composed of several metal horizontal strips with decreasing lengths to form an acute-angled isosceles triangle structure. The angle of the acute vertex is 30° ± 2°, the longest metal horizontal strip is 26 mm ± 0.5 mm, the shortest is 3 mm ± 0.5 mm, and the spacing between adjacent metal horizontal strips is 1.5 mm ± 0.1 mm.

[0057] The dielectric lens unit 12 is two juxtaposed inverted trapezoidal lenses. A slot is provided between the two inverted trapezoidal lenses to ensure that the dielectric lens unit 12 has no contact with the high-frequency radiator. The inclination angles of the two side inclined surfaces of the two inverted trapezoidal lenses are the same as the inclination angle of the side wall of the inverted trapezoidal metal cavity 9, both being 45° ± 2°.

[0058] See Figure 7 , the top of the co-aperture antenna substrate 4 near the coaxial line cabin 15 is fitted and connected with the co-aperture antenna substrate card slot 11 provided on the bottom surface of the coaxial line cabin metal cover 10.

[0059] See Figure 1 、 Figure 2 , the bottom of the co-aperture antenna substrate 4 is installed near both ends through the raised radiator fixing card slots 16.

[0060] See Figure 8 , wire clips 6 are respectively provided on both sides of the co-aperture antenna substrate card slot 11 and on one side wall surface of the metal cavity 9.

[0061] The metal is made of silver, copper or copper plated with silver on the surface.

[0062] This invention discloses the construction of a common-aperture carrier conformal ultrawideband end-fire antenna, achieving wideband impedance characteristics within a small size. Simultaneously, in a compact structure, the antenna maintains high port isolation between its two ports, enabling them to operate independently. This invention not only increases the channel capacity and anti-fading capability of flight platform antenna systems, but its excellent port and radiation characteristics also contribute to improving the overall performance of flight platform antenna systems, thereby achieving high-performance communication and anti-interference capabilities.

[0063] 1. Simulation Content

[0064] Simulation experiments were conducted on the antenna of the above embodiment using simulation software. The voltage standing wave ratio, port isolation, and radiation pattern of the antenna are shown below. Figures 9 to 22 .

[0065] 2. Simulation Results

[0066] Figure 9 , Figure 10 The figures show the voltage standing wave ratio (VSWR) as a function of operating frequency, obtained from simulation and actual measurements of the antenna in the embodiment. The VSWR of the low-frequency radiator 3 is less than 2.7 in the operating frequency band of 2.3–6 GHz, and the VSWR of the high-frequency radiator 3 is less than 2.7 in the operating frequency band of 6–18 GHz. Furthermore, the simulation and actual measurement results are in good agreement, indicating that the antenna of the present invention achieves significant broadband characteristics.

[0067] Figure 11 The curves showing the port isolation as a function of operating frequency, obtained from simulations of the antenna in the embodiment, illustrate this. Throughout the entire operating frequency band, the isolation between the two ports is greater than 15 dB for most of the operating frequency range. This result demonstrates that the antenna of the present invention exhibits good port isolation between its two polarizations.

[0068] Figures 12-23 The diagram shows the radiation patterns of the conformal ultra-wideband end-fire antenna on the common-aperture carrier obtained from the antenna simulation of the embodiment in the E-plane and H-plane. Throughout the entire frequency band, the antenna's vertically polarized beam points at 20°-120° in the E-plane and 0°-30° and 330°-360° in the azimuth plane. The antenna gain is generally greater than -6dB (approximately 95% of the frequency points), and the maximum beam pointing is slightly upward to about 60° in the elevation plane. These results demonstrate that the antenna of this invention exhibits high consistency between fabrication and measured data and stable gain characteristics.

[0069] The above are merely the preferred embodiments of the present invention and do not constitute any limitation on the present invention. Obviously, under the concept of the present invention, the structure, parameters and frequency of the present invention can be modified to obtain the broadband characteristics, high isolation characteristics and modularity of the antenna of the present invention, but these are all within the scope of protection of the present invention.

Claims

1. A co-bore super wideband end-fire antenna embedded in a metal carrier, comprising a metal cavity (9), a coaxial line bin (15) is arranged on one side of the metal cavity (9), and a radiator module is connected to the bottom of the metal cavity (9), characterized in that, The radiator module includes a common-aperture antenna substrate (4). On one side of the common-aperture antenna substrate (4) close to the coaxial cable chamber (15), a low-frequency radiator (3) is printed. On the side far from the coaxial cable chamber (15), a high-frequency radiator (5) is printed. A dielectric lens unit (12) covers the top of the high-frequency radiator (5). Above the dielectric lens unit (12) and above the metal cavity (9), a low-frequency antenna top-loading substrate (1) is covered. On the bottom surface of the low-frequency antenna top-loading substrate (1), a triangular strip top-loading structure (2) is printed. The triangular strip top-loading structure (2) is in contact and cooperation with the top of the low-frequency radiator (3). The low-frequency radiator (3) is connected to the low-frequency radiator SMA connector flange (1301) in the coaxial cable chamber (15) through a low-frequency coaxial feeder for feeding. The high-frequency radiator (5) is connected to the high-frequency radiator SMA connector flange (1302) in the coaxial cable chamber (15) through a high-frequency coaxial feeder for feeding. The metal cavity (9) is an inverted trapezoidal cavity with a wide upper mouth and a narrow bottom. An inclined comb-shaped slot line (3-1) is opened above the low-frequency radiator (3). The slot lines are arranged at equal intervals, with a spacing of 1.4 mm ± 0.2 mm. And at one end of the low-frequency radiator (3) close to the coaxial cable chamber (15), a "ji" - shaped slot line (3-2) is opened for connecting the coaxial cable. The high-frequency radiator (5) is printed on the common-aperture antenna substrate (4) along the inclined surface angle of the end of the inverted trapezoidal metal cavity (9). A comb-shaped slot line (5-1) is opened above the high-frequency radiator (5), and the comb-shaped slot lines (5-1) are arranged at equal intervals, with a spacing of 1.4 mm ± 0.2 mm. A small hole (5-2) is opened at the bottom of the high-frequency radiator (5) near the position of the low-frequency radiator (3) for connecting the coaxial cable. The triangular strip top-loading structure (2) is an acute-angled isosceles triangle structure composed of several metal horizontal strips with decreasing lengths. The angle of the acute vertex is 30° ± 2°. The longest metal horizontal strip is 26 mm ± 0.5 mm, and the shortest is 3 mm ± 0.5 mm. The spacing between adjacent metal horizontal strips is 1.5 mm ± 0.1 mm. The dielectric lens unit (12) is two juxtaposed inverted trapezoidal lenses. A slot is provided between the two inverted trapezoidal lenses to ensure that the dielectric lens unit (12) has no contact with the high-frequency radiator. The inclined angles of the two side inclined surfaces of the two inverted trapezoidal lenses are the same as the inclined angle of the side wall of the inverted trapezoidal metal cavity (9), both being 45° ± 2°. The top of the common-aperture antenna substrate (4) close to the coaxial cable chamber (15) is connected in cooperation with the common-aperture antenna substrate card slot (11) provided on the bottom surface of the coaxial cable chamber metal cover (10).

2. The common-aperture ultra-wideband end-fire antenna embedded in a metal carrier according to claim 1, characterized in that, Both the low-frequency radiator (3) and the high-frequency radiator (5) are made of metal materials.

3. The common-aperture ultra-wideband end-fire antenna embedded in a metal carrier according to claim 1, characterized in that, Wire clips (6) are respectively provided on both sides of the common-aperture antenna substrate card slot (11) and on one side wall surface of the metal cavity (9).

4. A common-aperture ultra-wideband end-fire antenna embedded in a metal carrier according to any one of claims 1 to 3, characterized in that, The metal is silver, copper or copper plated with silver on the surface.

Images