Functional composite one-dimensional metal cavity slot array antenna and array thereof

Abstract

This invention provides a functional composite one-dimensional metallic cavity slot array antenna, belonging to the field of antennas. It includes a feed cavity and a cover plate on top of the feed cavity. The feed cavity contains multiple sets of periodic intermediate-frequency anti-interference metal blocks and high-frequency anti-interference metal blocks. Radiation slots are formed on the cover plate. A stepped and open polarization conversion structure is arranged on both sides of the radiation slots, creating an undulating topography. An antenna array is also provided. The feed cavity embeds an anti-interference periodic structure, giving the antenna anti-interference capabilities in multiple different frequency bands. The stepped and open polarization conversion structure is arranged on both sides of the radiation slots, creating an undulating topography. Electromagnetic signals are input into the feed cavity and radiate linearly polarized electromagnetic waves outward through the radiation slots. After passing through the polarization conversion structure, the linearly polarized electromagnetic waves are decomposed into a set of orthogonal components with equal amplitude. There is a 90-degree phase difference between the two components, forming circular polarization radiation into space. The polarization conversion structure is simple in structure, easy to manufacture, and improves the antenna's scattering characteristics.

Description

Technical Field

[0001] This invention relates to the field of antenna technology, and in particular to a functional composite one-dimensional metal cavity slot array antenna and its array. Background Technology

[0002] Metal cavity slot array antennas are a classic antenna type based on a metal cavity structure and slot radiating elements. These antennas achieve efficient signal transmission or reception by designing specific slot structures within the metal cavity and utilizing the cavity's resonant characteristics and the slots' radiation characteristics. Due to their advantages such as low loss and high polarization purity, they have received widespread attention in military applications such as spaceborne and airborne communications and radar.

[0003] However, due to the continuous advancement of electronic technology, the current electromagnetic environment is extremely complex. Spaceborne or airborne applications must consider internal interference within their own equipment and also take effective measures to counter enemy electromagnetic interference. Therefore, improving the anti-interference capability of metal cavity slotted array antennas is essential.

[0004] Furthermore, antennas are mainly classified into two types based on their polarization: linear polarization and circular polarization. Linear polarization includes horizontal polarization, vertical polarization, and slant polarization, while circular polarization mainly includes left-hand circular polarization and right-hand circular polarization. A circularly polarized antenna is a special type of antenna whose transmitted or received electromagnetic waves have a rotating electric field vector direction. This characteristic gives circularly polarized antennas significant advantages in many applications. Especially in applications such as satellite-to-Earth communication or imaging, using circular polarization can effectively avoid the adverse effects of high path loss and polarization mismatch caused by the Faraday rotation effect when electromagnetic waves penetrate the ionosphere.

[0005] In summary, addressing the issues of interference suppression and circular polarization in metal cavity slot array antennas is a key focus of this invention. One-dimensional linear arrays, being the simplest form of metal cavity slot array antennas, offer significant potential for technological improvements. Currently, interference suppression in metal cavity slot array antennas is often achieved by cascading filters at the antenna's rear end, significantly increasing system complexity, hindering engineering implementation, and incurring substantial system losses. Furthermore, existing methods for achieving circular polarization in metal cavity slot array antennas typically involve adding polarization conversion devices, which are usually cumbersome to manufacture and costly. Summary of the Invention

[0006] The technical problem to be solved by this invention is: how to solve the problems of complex structure of existing metal cavity slot array antennas and the cumbersome processing and high manufacturing cost of using polarization conversion devices to achieve circular polarization.

[0007] The present invention solves the above-mentioned technical problems through the following technical solution: a functional composite one-dimensional metal cavity slot array antenna, the antenna including a feed cavity and a cover plate located on top of the feed cavity, the feed cavity is provided with multiple sets of periodic intermediate frequency anti-interference metal blocks and high frequency anti-interference metal blocks, the cover plate is provided with radiation slots, and the polarization conversion structure is arranged in a stepped and open manner on both sides of the radiation slots to form a high and low undulating morphology.

[0008] Beneficial Effects: This invention endows the antenna with anti-interference capabilities across multiple frequency bands by embedding a simple anti-interference periodic structure within the feed cavity. Compared to the traditional method of cascading filters at the antenna end, this invention effectively avoids cascading losses and reduces system size to some extent. The polarization conversion structure is arranged in a stepped and open manner on both sides of the radiation slot, creating an undulating topography. Electromagnetic signals are input into the feed cavity and radiated outward through the radiation slot as linearly polarized electromagnetic waves. After passing through the polarization conversion structure, the linearly polarized electromagnetic waves are decomposed into a set of orthogonal components with equal amplitude and a 90-degree phase difference between the two components, thus forming circular polarization and radiating into space. The polarization conversion structure is simple in structure, easy to manufacture, and has excellent performance. Furthermore, the antenna array exhibits a rough, undulating topography. According to the theory of diffuse reflection of electromagnetic waves, when electromagnetic waves strike a rough surface, the incident electromagnetic waves can generate phase differences at the interface, and the scattered energy can be distributed at multiple angles, resulting in diffuse reflection and weakened reflection, thereby effectively improving the antenna's scattering characteristics.

[0009] Preferably, when the antenna is transmitting, the electromagnetic signal is fed into the feed cavity and radiates linearly polarized electromagnetic waves outward through the radiation slot. After passing through the polarization conversion structure, the linearly polarized electromagnetic waves are decomposed into a set of orthogonal components with equal amplitudes and a 90-degree phase difference between the two components, forming circular polarization and radiating into space. When the antenna is receiving, the process is exactly the opposite of the transmitting process.

[0010] Preferably, the front end of the feeding cavity is configured as a feeding port protruding from the feeding cavity body, the rear end of the feeding cavity is closed, four radial slots are equally spaced along the long side center axis of the cover plate, and four tuning metal blocks are equally spaced along the bottom long side center axis of the cover plate, with the tuning metal blocks staggered on both sides of the radial slots.

[0011] Preferably, the 32 intermediate frequency anti-interference metal blocks are divided into 8 groups, with 4 intermediate frequency anti-interference metal blocks in each group being equally spaced on the intermediate frequency metal pad along the width direction of the cover plate. The 128 high frequency anti-interference metal blocks are divided into 8 groups, with 16 high frequency anti-interference metal blocks in each group forming a 2×8 array arranged on the high frequency metal pad. The intermediate frequency anti-interference metal blocks in each group and the high frequency anti-interference metal blocks in each group are alternately arranged along the length direction of the cover plate, and the upper surface of the intermediate frequency anti-interference metal blocks is flush with the upper surface of the high frequency anti-interference metal blocks.

[0012] Beneficial effects: The mid-frequency and high-frequency anti-interference metal blocks can be considered ideal magnetic conductors, significantly suppressing the propagation of electromagnetic waves in their respective frequency bands while having no effect on electromagnetic waves in other frequency bands. Therefore, the antenna possesses mid-frequency and high-frequency anti-interference capabilities. Furthermore, because the feed cavity uses a metallic waveguide structure, and waveguides have inherent cutoff frequency properties, electromagnetic waves below the corresponding frequency cannot propagate within it; therefore, the antenna also possesses low-frequency anti-interference capabilities.

[0013] Preferably, the upper surface of the intermediate frequency anti-interference metal block is flush with the lower edge of the power supply port.

[0014] Preferably, the polarization conversion structure includes 8 basic units. Each basic unit includes a polarization conversion metal block 1, a polarization conversion metal block 2, and a polarization conversion metal block 3, each with different heights and widths. The three metal blocks are all located on the top of the cover plate, and the end faces of the three metal blocks are closely attached to form a stepped shape.

[0015] Beneficial effects: The antenna structure of this invention features weak electromagnetic reflection, meaning it reduces the RCS (Radar Cross Section), making it highly promising for applications in electromagnetic stealth design. The polarization conversion structure is an open structure, which eliminates electromagnetic wave transmission cutoff issues and facilitates wider operating bandwidth. Furthermore, the open structure improves antenna heat dissipation, facilitates machining, reduces the vertical movement path of the machining tool, and lowers manufacturing costs.

[0016] Preferably, the first end face of polarization conversion metal block one is closely attached to the second end face of polarization conversion metal block two, the third end face of polarization conversion metal block two is closely attached to the fourth end face of polarization conversion metal block three, and the first side face of polarization conversion metal block one is flush with the second side face of polarization conversion metal block two and the third side face of polarization conversion metal block three.

[0017] Beneficial effects: The close contact between the end faces of the three metal blocks increases the strength of the antenna structure and provides good protection against antenna deformation.

[0018] Preferably, the height of polarization conversion metal block one is half the working wavelength, the height of polarization conversion metal block two is one-quarter of the working wavelength, and the height of polarization conversion metal block three is used to adjust the impedance matching of the overall antenna structure.

[0019] Beneficial effects: The polarization conversion structure of this invention is set as an open structure. Compared with the closed structure with cavity, the electromagnetic waves of the open structure are easy to diverge and are not easy to form directional radiation, resulting in lower directional radiation gain. To address this problem, this invention can improve the directional radiation gain by reasonably designing and optimizing the height and width of polarization conversion metal block one, polarization conversion metal block two, and polarization conversion metal block three, thereby improving the circular polarization radiation performance of the antenna.

[0020] The present invention also provides a functional composite one-dimensional metal cavity slot array antenna array, which uses the aforementioned functional composite one-dimensional metal cavity slot array antenna as antenna element, and arranges multiple antenna elements in a planar array. The feed ports of each row of antenna elements are located on the same side, and the rear ends of the feed cavities of adjacent rows of antenna elements are closely aligned. The upper surfaces of all antenna elements are flush.

[0021] Beneficial effects: The antenna of this invention has a flat structure, which is extremely convenient for array applications. The antenna can be manufactured using milling technology, which is a mature process with high reliability, wide application range, and low cost.

[0022] The present invention also provides a functional composite one-dimensional metal cavity slot array antenna array, which uses the aforementioned functional composite one-dimensional metal cavity slot array antenna as antenna element, and is coarsely arranged by multiple antenna elements. The feed ports of each row of antenna elements are located on the same side, the rear ends of the feed cavities of adjacent two rows of antenna elements are closely attached and have a certain height difference, and the upper surfaces of any two adjacent antenna elements are not flush.

[0023] Beneficial effects: By setting the array of one-dimensional metal cavity slot array antennas to have a rough undulating topography, the "roughness" of the large-scale array surface is further improved, thereby effectively improving the scattering characteristics of the antenna. Attached Figure Description

[0024] Figure 1 A perspective view of the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0025] Figure 2 This is a perspective view of the functional composite one-dimensional metal cavity slot array antenna provided in Embodiment 1 of the present invention.

[0026] Figure 3 This is a front view of the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0027] Figure 4 This is a top view of the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0028] Figure 5 This is a side view of the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0029] Figure 6 This is a perspective view of the feed cavity and anti-interference structure of the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0030] Figure 7This is a front view of the feeding structure and anti-interference structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0031] Figure 8 This is a top view of the feeding structure and anti-interference structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0032] Figure 9 This is a side view of the feeding structure and anti-interference structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0033] Figure 10 This is a perspective view of the feeding structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0034] Figure 11 A perspective view of the feed cavity of the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0035] Figure 12 A perspective view of the cover plate in the functional composite one-dimensional metal cavity slot array antenna provided in Embodiment 1 of the present invention;

[0036] Figure 13 This is a front view of the cover plate in the functional composite one-dimensional metal cavity slot array antenna provided in Embodiment 1 of the present invention;

[0037] Figure 14 This is a bottom view of the cover plate in the functional composite one-dimensional metal cavity slot array antenna provided in Embodiment 1 of the present invention;

[0038] Figure 15 This is a side view of the cover plate in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0039] Figure 16 This is a three-dimensional view of the anti-interference structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0040] Figure 17 This is a front view of the anti-interference structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0041] Figure 18 This is a top view of the anti-interference structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0042] Figure 19 This is a side view of the anti-interference structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0043] Figure 20 This is a perspective view of the cover plate and polarization conversion structure in the functional composite one-dimensional metal cavity slot array antenna provided in Embodiment 1 of the present invention;

[0044] Figure 21 This is a front view of the cover plate and polarization conversion structure in the functional composite one-dimensional metal cavity slot array antenna provided in Embodiment 1 of the present invention;

[0045] Figure 22 This is a top view of the cover plate and polarization conversion structure in the functional composite one-dimensional metal cavity slot array antenna provided in Embodiment 1 of the present invention;

[0046] Figure 23 This is a side view of the cover plate and polarization conversion structure in the functional composite one-dimensional metal cavity slot array antenna provided in Embodiment 1 of the present invention;

[0047] Figure 24 A three-dimensional view of the basic unit of the polarization conversion structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0048] Figure 25 This is a front view of the basic unit of the polarization conversion structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0049] Figure 26 This is a top view of the basic unit of the polarization conversion structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0050] Figure 27 This is a side view of the basic unit of the polarization conversion structure in the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention.

[0051] Figure 28 The impedance matching performance curve of the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0052] Figure 29 The circular polarization performance curve of the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0053] Figure 30 The scattering performance curve of the functional composite one-dimensional metallic cavity slot array antenna provided in Embodiment 1 of the present invention;

[0054] Figure 31 This is a top view of the functional composite one-dimensional metal cavity slot array antenna array provided in Embodiment 2 of the present invention;

[0055] Figure 32This is a schematic diagram of a planar array for the functional composite one-dimensional metal cavity slot array antenna array provided in Embodiment 2 of the present invention;

[0056] Figure 33 A side view of the planar array of the functional composite one-dimensional metal cavity slot array antenna array provided in Embodiment 2 of the present invention;

[0057] Figure 34 This is a schematic diagram of a coarse array for the functional composite one-dimensional metal cavity slot array antenna array provided in Embodiment 2 of the present invention;

[0058] Figure 35 A side view of the functional composite one-dimensional metal cavity slot array antenna array provided in Embodiment 2 of the present invention, using a coarse array arrangement;

[0059] Figure 36 A side view of the functional composite one-dimensional metal cavity slot array antenna array provided in Embodiment 2 of the present invention, using a coarse array configuration from another perspective;

[0060] In the figure: 1. Power supply structure, 102. Power supply cavity, 103. Cover plate, 2. Anti-interference structure, 201. Intermediate frequency anti-interference metal block, 202. High frequency anti-interference metal block, 203. High frequency metal pad, 204. Intermediate frequency metal pad, 3. Polarization conversion structure, 301. Polarization conversion metal block one, 3011. First end face, 3012. First side face, 3021. Second end face, 3022. Third end face, 3023. Second side face, 3031. Fourth end face, 3032. Third side face, 302. Polarization conversion metal block two, 303. Polarization conversion metal block three. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0062] Example 1

[0063] like Figure 1-9 As shown, this embodiment provides a functionally composite one-dimensional metallic cavity slot array antenna, employing an all-metal structure, exhibiting high radiation efficiency and large power capacity. The antenna includes a feeding structure 1, an anti-interference structure 2, and a polarization conversion structure 3. See [link to documentation]. Figure 10 and Figure 16The power supply structure 1 includes a power supply cavity 102 and a cover plate 103 located on top of the power supply cavity 102. The power supply cavity 102 is provided with multiple sets of periodic intermediate frequency anti-interference metal blocks 201 and high frequency anti-interference metal blocks 202. Radiation slots 104 are opened on the cover plate 103. The polarization conversion structure 3 is arranged in a stepped and open manner on both sides of the radiation slots 104 to form a high and low undulating shape.

[0064] by Figure 1 In the diagram, the X direction represents the front-to-back direction of the antenna, the Y direction represents the left-to-right direction, and the Z direction represents the up-to-down direction. The feed structure 1 uses a metal waveguide structure, the feed cavity 102 is a rectangular slot, and the cover plate 103 is a metal cover plate. The length direction of the rectangular slot is parallel to the X direction, the width direction is parallel to the Y direction, and the height direction is parallel to the Z direction. See also... Figures 10 to 15 The front end of the feed cavity 102 is configured as a feed port 101 protruding from the body of the feed cavity 102. The rear end of the feed cavity 102 is closed. Four radial slots 104 are equally spaced along the long side central axis of the cover plate 103. The radial slots 104 can be straight, elliptical, S-shaped, or H-shaped. Four tuning metal blocks 105 are equally spaced along the bottom long side central axis of the cover plate 103. The tuning metal blocks 105 are staggered on both sides of the radial slots 104. See [reference needed]. Figure 14 The right edge of the first tuning metal block 105 is close to the left edge of the first radial slit 104, the left edge of the second tuning metal block 105 is close to the right edge of the second radial slit 104, the right edge of the third tuning metal block 105 is close to the left edge of the third radial slit 104, and the left edge of the fourth tuning metal block 105 is close to the right edge of the fourth radial slit 104.

[0065] See Figures 16 to 19 The 32 intermediate frequency anti-interference metal blocks 201 are divided into 8 groups. The 4 intermediate frequency anti-interference metal blocks 201 in each group are set at equal intervals along the Y direction on the intermediate frequency metal pad 204. The 128 high frequency anti-interference metal blocks 202 are divided into 8 groups. The 16 high frequency anti-interference metal blocks 202 in each group form a 2×8 array arranged on the high frequency metal pad 203. The intermediate frequency anti-interference metal blocks 201 and the high frequency anti-interference metal blocks 202 in each group are alternately arranged along the X direction. The sum of the heights of the high frequency anti-interference metal blocks 202 and the high frequency metal pad 203 is equal to the sum of the heights of the intermediate frequency anti-interference metal blocks 201 and the intermediate frequency metal pad 204. That is, the upper surface of the intermediate frequency anti-interference metal block 201 is flush with the upper surface of the high frequency anti-interference metal block 202, and the upper surface of the intermediate frequency anti-interference metal block 201 is flush with the lower edge of the feed port 101.

[0066] The intermediate frequency (IF) anti-interference metal block 201 and the high frequency anti-interference metal block 202 can be considered as ideal magnetic conductors, exhibiting a significant suppression effect on the propagation of electromagnetic waves in their respective frequency bands, while having no effect on electromagnetic waves in other frequency bands. Therefore, the one-dimensional metal cavity slot array antenna of this embodiment possesses IF and high frequency anti-interference capabilities. Furthermore, since the feed cavity employs a metal waveguide structure, and waveguides have inherent cutoff frequency properties, electromagnetic waves below the corresponding frequency cannot propagate within it. Therefore, the antenna of this embodiment also possesses low-frequency anti-interference capabilities.

[0067] This invention endows the antenna with anti-interference capability in multiple different frequency bands by embedding a simple anti-interference periodic structure in the feed cavity. Compared with the traditional form of cascading filters at the antenna end, the antenna of this invention can effectively avoid cascading losses and reduce the size of the system to a certain extent.

[0068] Polarization conversion structures possess excellent circular polarization radiation capability, and due to their uneven surface, they can also improve the antenna's scattering characteristics to some extent. (See also...) Figures 20 to 27 The polarization conversion structure 3 comprises 8 basic units. Figure 24 This is a three-dimensional diagram of the basic unit of the polarization conversion structure 3. Each basic unit includes polarization conversion metal block 1 301, polarization conversion metal block 2 302, and polarization conversion metal block 303. The height and width of polarization conversion metal block 1 301, polarization conversion metal block 2 302, and polarization conversion metal block 303 are different. The size of the three metal blocks is random and can be adjusted appropriately according to the different antenna operating frequency requirements. All three metal blocks are located on top of the cover plate 103, with their end faces closely abutting each other to form a stepped structure. The first end face 3011 of polarization conversion metal block one 301 is closely abutting the second end face 3021 of polarization conversion metal block two 302, and the third end face 3022 of polarization conversion metal block two 302 is closely abutting the fourth end face 3031 of polarization conversion metal block three 303. Furthermore, the first side face 3012 of polarization conversion metal block one 301 is flush with the second side face 3023 of polarization conversion metal block two 302 and the third side face 3032 of polarization conversion metal block three 303. The end face of polarization conversion metal block one 301 that faces the first end face 3011 is the fifth end face, and the end face of polarization conversion metal block three 303 that faces the fourth end face 3031 is the sixth end face. (Continue to the previous section...) Figure 1Eight basic units are evenly distributed on both sides of the radiation slot 104, with four basic units on each side. The two basic units at the front and back are set in close contact. Taking two basic units as an example, when the front basic unit and the back basic unit are set in close contact, the fifth end face of the polarization conversion metal block 301 in the front basic unit is in close contact with the sixth end face of the polarization conversion metal block 303 in the back basic unit. The polarization conversion structure 3 of this invention has a simple structure, is easy to process and manufacture, and has excellent performance. At the same time, the polarization conversion structure has the characteristic of uneven surface, which can improve the scattering characteristics of the antenna to a certain extent. The close contact of the end faces of the three metal blocks makes the antenna structure stronger and provides good protection against antenna deformation.

[0069] Each basic unit is stepped, and multiple basic units are arranged on both sides of the radiation slot 104 to form an undulating topography, giving the antenna array a rough, uneven topography. According to the theory of diffuse reflection of electromagnetic waves, when electromagnetic waves irradiate a rough surface, the incident electromagnetic waves can produce a phase difference at the interface, and the scattered energy can be distributed in multiple angles, resulting in diffuse reflection and weakening of reflection, thereby effectively improving the scattering characteristics of the antenna. Based on this characteristic, the antenna structure of the present invention has the characteristic of weak electromagnetic reflection, that is, the antenna structure has the characteristic of reducing RCS, and has great application prospects in the field of electromagnetic stealth design. The polarization conversion structure 3 is an open structure. The open structure does not have the problem of electromagnetic wave transmission cutoff, because when the electromagnetic wave frequency is low, the four-sided closed structure may have transmission cutoff. Compared with the four-sided closed structure, the open structure is more conducive to widening the working bandwidth. In addition, the open structure is more conducive to antenna heat dissipation, easier to machine, and can reduce the movement path of the machining tool in the vertical direction, reducing manufacturing costs.

[0070] When the antenna of this invention is transmitting, the electromagnetic signal is input into the feed cavity 102 through the feed port 101, and radiates outward as a linearly polarized electromagnetic wave through the radiation slot 104. After passing through the polarization conversion structure 3, the linearly polarized electromagnetic wave is decomposed into a set of orthogonal components of equal amplitude, with a 90-degree phase difference between the two components, thus forming circular polarization and radiating into space. When the antenna is receiving, the process is exactly the reverse of the transmitting process. See also... Figures 28 to 30 One-dimensional metal cavity slot array antennas have good impedance matching characteristics within the operating frequency band and three anti-interference frequency bands outside the operating frequency band. The antennas have good circular polarization characteristics within the operating frequency band. Compared with one-dimensional metal cavity slot array antennas with smooth surfaces, the scattering characteristics of one-dimensional metal cavity slot array antennas with "rough" surfaces are adjusted to a certain extent.

[0071] The antenna of this invention features a flat structure, making it extremely convenient for array applications. The antenna can be manufactured using milling technology, a mature process with high reliability, wide application range, and low cost. This invention not only solves the problems of anti-interference and circular polarization requirements for one-dimensional metal cavity slot array antennas, but also boasts excellent performance, simple structure, and ease of manufacturing.

[0072] The polarization conversion structure 3 of this invention is designed as an open structure. Compared to a closed structure with cavities, the electromagnetic waves of an open structure tend to diverge easily, making it difficult to form directional radiation and resulting in lower directional radiation gain. To address this issue, this invention improves the directional radiation gain and thus enhances the circular polarization radiation performance of the antenna by rationally designing and optimizing the height and width of polarization conversion metal blocks 301, 302, and 303. The lengths of polarization conversion metal blocks 301, 302, and 303 (parallel to the X direction of the radiation slot) are the same, and the three metal blocks are evenly distributed in a direction parallel to the radiation slot. The height primarily affects the phase of the electromagnetic wave components, while the width primarily affects their amplitude. In this embodiment, the height of polarization conversion metal block 1 (301) is approximately half the operating wavelength, and the height of polarization conversion metal block 2 (302) is approximately one-quarter of the operating wavelength. The 90-degree phase difference forming circular polarization is generated by polarization conversion metal block 2 (302). The height of polarization conversion metal block 3 (303) is used to adjust the impedance matching of the overall antenna structure. By adjusting the widths (perpendicular to the Y direction of the radiation slot) of polarization conversion metal blocks 1 (301), 2 (302), and 3 (303), the amplitudes of the two electric field components forming circular polarization can be adjusted, thus achieving the desired amplitudes. By appropriately designing the widths of the three metal blocks, two electric field components with equal amplitudes can be generated. The widths of the three metal blocks should not be too large, otherwise they will obstruct the radiation slot. The width of the shortest metal block is typically half its length; in this embodiment, the shortest metal block has a length of 17.6 mm and a width of 8 mm. The width of the three metal blocks increases sequentially from the shortest to the tallest. The operating frequency band and bandwidth of the antenna can be optimized by adjusting the gradual change in the width of the three metal blocks.

[0073] Example 2

[0074] The difference between this embodiment and embodiment 1 is that this embodiment uses the functional composite one-dimensional metal cavity slot array antenna of embodiment 1 as an independent antenna unit to construct antenna arrays of different sizes. This embodiment takes a 2×4 antenna array as an example to introduce the array of the one-dimensional metal cavity slot array antenna. The antenna array can be arranged in a planar array or a coarse array.

[0075] like Figures 31 to 33As shown, the antenna array adopts a planar array configuration and includes eight one-dimensional metal cavity slot array antennas, namely antenna element one to antenna element eight. The eight one-dimensional metal cavity slot array antennas are closely combined to form a 2×4 array with their upper surfaces flush, that is, the upper surfaces of antenna element one to antenna element eight are flush. The feed ports 101 of the four one-dimensional metal cavity slot array antennas in each row are located on the same side, and the rear ends of the feed cavities 102 of the one-dimensional metal cavity slot array antennas in two adjacent rows are closely aligned.

[0076] like Figures 34 to 36 As shown, the antenna array employs a coarse arrangement and includes eight one-dimensional metal cavity slot array antennas. These eight antennas are tightly combined to form a 2×4 array, with the upper surfaces of any two adjacent antennas not flush. The upper surfaces of antenna elements one, three, six, and eight are higher than the upper surfaces of antenna elements two, four, five, and seven. The feed ports 101 of the four antennas in each row are located on the same side, and the rear ends of the feed cavities 102 of adjacent rows are closely fitted together with a certain height difference. By arranging the one-dimensional metal cavity slot array antennas in a coarse, undulating shape, the "roughness" of the large-scale array surface is further improved, thereby effectively improving the antenna's scattering characteristics.

[0077] It should be noted that this embodiment uses a 2×4 antenna array as an example only, and professionals can make any extensions and improvements based on it. At the same time, for the "rough array" of the 2×4 antenna array, only one height scheme is provided. Professionals can design each antenna element to its own appropriate height according to the actual situation, thereby further optimizing the "roughness" of the large-scale array surface.

[0078] This invention not only provides a "rough surface" design scheme for antenna elements, but also a "rough array" design scheme for large-scale arrays, which has significant benefits for adjusting the scattering performance of metal cavity slot antenna elements and their arrays. Based on milling technology, large-scale arrays based on this antenna element can be processed as a whole, rather than processing the elements independently and then splicing them together. This method can ensure processing accuracy and reduce processing costs.

[0079] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A functional composite one-dimensional metallic cavity slot array antenna, characterized in that: The antenna includes a feed cavity, a cover plate located on top of the feed cavity, and a polarization conversion structure. The feed cavity is equipped with multiple sets of periodic intermediate frequency (IF) anti-interference metal blocks and high frequency anti-interference metal blocks. Each set of IF anti-interference metal blocks and each set of high frequency anti-interference metal blocks are alternately arranged along the length of the cover plate. The upper surface of the IF anti-interference metal blocks is flush with the upper surface of the high frequency anti-interference metal blocks. Radiation slots are opened on the cover plate. The polarization conversion structure is arranged in a stepped and open manner on both sides of the radiation slots to form an undulating shape. Each basic unit of the polarization conversion structure includes polarization conversion metal block one, polarization conversion metal block two, and polarization conversion metal block three, which have different heights and widths. The three polarization conversion metal blocks are all located on the top of the cover plate, and the end faces of the three polarization conversion metal blocks are closely attached to form a stepped shape.

2. The functional composite one-dimensional metallic cavity slot array antenna according to claim 1, characterized in that: When the antenna is transmitting, the electromagnetic signal is fed into the feed cavity and radiates linearly polarized electromagnetic waves outward through the radiation slot. After passing through the polarization conversion structure, the linearly polarized electromagnetic waves are decomposed into a set of orthogonal components with equal amplitudes and a 90-degree phase difference between the two components, forming circular polarization and radiating into space. When the antenna is receiving, the process is exactly the opposite of the transmitting process.

3. The functional composite one-dimensional metallic cavity slot array antenna according to claim 1, characterized in that: The front end of the feeding cavity is configured as a feeding port protruding from the feeding cavity body, and the rear end of the feeding cavity is closed. Four radial slots are equally spaced along the long side center axis of the cover plate, and four tuning metal blocks are equally spaced along the bottom long side center axis of the cover plate. The tuning metal blocks are staggered on both sides of the radial slots.

4. The functional composite one-dimensional metallic cavity slot array antenna according to claim 1, characterized in that: The 32 intermediate frequency anti-interference metal blocks are divided into 8 groups. The 4 intermediate frequency anti-interference metal blocks in each group are set at equal intervals along the width of the cover plate on the intermediate frequency metal pad. The 128 high frequency anti-interference metal blocks are divided into 8 groups. The 16 high frequency anti-interference metal blocks in each group form a 2×8 array arranged on the high frequency metal pad.

5. The functional composite one-dimensional metallic cavity slot array antenna according to claim 2, characterized in that: The upper surface of the intermediate frequency anti-interference metal block is flush with the lower edge of the power supply port.

6. The functional composite one-dimensional metallic cavity slot array antenna according to claim 1, characterized in that: The polarization conversion structure consists of 8 basic units.

7. The one-dimensional metallic cavity slot array antenna according to claim 6, characterized in that: The first end face of polarization conversion metal block one is in close contact with the second end face of polarization conversion metal block two, the third end face of polarization conversion metal block two is in close contact with the fourth end face of polarization conversion metal block three, and the first side face of polarization conversion metal block one is flush with the second side face of polarization conversion metal block two and the third side face of polarization conversion metal block three.

8. The functional composite one-dimensional metallic cavity slot array antenna according to claim 6, characterized in that: The height of polarization conversion metal block one is half the working wavelength, the height of polarization conversion metal block two is one-quarter of the working wavelength, and the height of polarization conversion metal block three is used to adjust the impedance matching of the overall antenna structure.

9. A functional composite one-dimensional metallic cavity slot array antenna array, characterized in that: Using the functional composite one-dimensional metal cavity slot array antenna as described in any one of claims 1-8 as the antenna element, multiple antenna elements are arranged in a planar array, the feed ports of each row of antenna elements are located on the same side, the rear ends of the feed cavities of adjacent rows of antenna elements are closely aligned, and the upper surfaces of all antenna elements are flush.

10. A functional composite one-dimensional metallic cavity slot array antenna array, characterized in that: Using the functional composite one-dimensional metal cavity slot array antenna as described in any one of claims 1-8 as the antenna element, multiple antenna elements are coarsely arranged, the feed ports of each row of antenna elements are located on the same side, the rear ends of the feed cavities of two adjacent rows of antenna elements are closely attached and have a certain height difference, and the upper surfaces of any two adjacent antenna elements are not flush.

Images