Light ultra-wideband low-profile filtering antenna, antenna array and preparation method

Abstract

The invention discloses a light ultra-wideband low-profile filtering antenna, an antenna array and a preparation method, and relates to the technical field of microwave antennae, the light ultra-wideband low-profile filtering antenna comprises two layers of antenna radiation parts, rectangular radiation patch patterns are processed by using thin medium copper-clad plates, and the two layers of antenna radiation parts and two layers of PMI foam form a radiation part of an integrated antenna through a lamination technology; a slot coupling feed technology is utilized to open a slot in a floor, a strip line is utilized to excite a radiation patch through H-shaped slot electromagnetic coupling, and a coaxial-strip line transition structure is further integrated on a strip line layer; integrating the printed board with a metal base in a hot pressing mode; then, integrating the ring isolation-filtering assembly with the antenna through an SMT technology; and finally, the SMP coaxial connector is assembled through a clamping process to form a connecting port for a rear-end TR assembly, so that the rear-end TR assembly can be conveniently integrated with a rear-end module. The antenna is reasonable in design, achieves excellent impedance matching and radiation characteristics within the frequency band of 12-18 GHz, has a good out-of-band rejection function, and is compact in structure, reliable in process and suitable for batch production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave antenna, more particularly to the technical field of a light-weight ultra-wideband low-profile filtering antenna, an antenna array and a preparation method. BACKGROUND

[0002] With the rapid development of modern wireless communication, radar detection, electronic countermeasure and other systems, the performance requirements of antennas are increasingly improved. In particular, in the wideband microwave frequency band, the system usually requires the antenna to have wideband, high gain, low profile, light weight, easy integration and good out-of-band suppression characteristics.

[0003] Microstrip patch antennas are widely used due to their low profile, light weight, easy processing and integration with circuits. However, the traditional single-layer microstrip patch antenna has the inherent disadvantage of narrow bandwidth (usually only a few percent), which is difficult to meet the needs of wideband applications. In order to expand the bandwidth, various schemes have been proposed, such as using a multi-layer patch structure, using a thick dielectric substrate or a low dielectric constant material, and using electromagnetic coupling (such as slot coupling) feeding methods.

[0004] The slot coupling feeding technology opens a slot on the ground plane and uses a strip line to excite the radiation patch through H-shaped slot electromagnetic coupling, effectively separating the feeding network from the radiation part. The advantage of this structure is that it avoids the interference of the feed line with the radiation, reduces the surface wave excitation, and can optimize the impedance matching by adjusting the shape and size of the slot. In particular, after the radiation part adopts a double-layer patch, an additional resonance point is introduced, forming a staggered tuning characteristic, which effectively expands the bandwidth of the antenna.

[0005] On the other hand, modern radio frequency front-end systems are usually composed of multiple discrete devices such as antennas, filters, amplifiers, etc. This discrete structure not only increases the volume, weight and cost of the system, but also reduces the overall efficiency of the system due to the insertion loss introduced by connectors, transmission lines, etc. Therefore, integrating the filtering function with the antenna to form a filtering antenna with frequency selection characteristics has become a research hotspot. However, how to efficiently and compactly integrate the filtering structure into the antenna without sacrificing the antenna radiation performance and achieving good out-of-band suppression is a technical difficulty.

[0006] Existing filtering antenna design schemes directly print the filtering circuit on the antenna feed network, which may lead to complex feed network and increase loss; some use a multi-layer structure to place the resonator near the antenna layer, but often affect the antenna radiation pattern or make the processing process complex and reduce reliability. In particular, when the antenna is integrated with other active / passive devices on a metal substrate and subjected to the high-temperature process of surface mount technology (SMT) reflow soldering, the structural stability, material selection and integration method of the antenna are challenged.

[0007] Therefore, there is an urgent need in the field for a new antenna design that can simultaneously achieve ultra-wideband operation, high-gain radiation, strong out-of-band suppression, and a robust and stable structure that can be easily integrated with other microwave components with high reliability using standard SMT processes. Summary of the Invention

[0008] The purpose of this invention is to address the aforementioned technical problems by providing a lightweight ultra-wideband low-profile filtered antenna, antenna array, and fabrication method. This antenna achieves excellent impedance matching and radiation characteristics in the 12-18 GHz frequency band through collaborative innovative design in areas such as a lightweight foam dielectric double-layer patch radiating structure, H-shaped slotted stripline coupled feeding, and SMT integrated ring spacer / filter components. It also possesses good out-of-band suppression capabilities, a compact structure, reliable fabrication, and is suitable for mass production.

[0009] To achieve the above objectives, the present invention specifically adopts the following technical solution: The first aspect of the present invention provides a lightweight ultrawideband low-profile filter antenna, comprising, from top to bottom, a first radiating patch, a first PMI foam, a second radiating patch, a second PMI foam, an H-type coupling slot, a stripline feed layer, a coaxial adapter and shielding post, a stripline adapter layer, a ring-block filter assembly, a metal substrate, and an SMP coaxial connector. The first radiating patch and the second radiating patch are copper-clad boards with the lower copper-clad layer etched away. The upper copper-clad layer of the copper-clad boards of the first radiating patch and the second radiating patch has a rectangular radiating patch pattern. The first radiating patch and the second radiating patch are respectively pressed together with the first PMI foam and the second PMI foam to form the radiating part of the antenna. The H-shaped coupling slot is a copper-clad board with the lower copper layer etched away. Several H-shaped slot structures are provided on the upper copper layer of the H-shaped coupling slot. Each slot structure corresponds orthogonally to one end of the two branches of the stripline feed layer. The other end of the stripline feed layer corresponds to a stripline port of the stripline adapter layer through the coaxial adapter and shielding post. Some stripline ports of the stripline adapter layer are interconnected with the corresponding ports of the ring filter component. Some stripline ports of the stripline adapter layer are interconnected with the interface of the SMP coaxial connector.

[0010] In one embodiment, the stripline adapter layer includes a stripline first port, a stripline second port, a stripline third port, a stripline fourth port, a stripline fifth port, and a stripline sixth port; The other end of the stripline in the stripline feed layer corresponds to the first port of the stripline in the stripline adapter layer via the coaxial adapter and shielding post. The second port of the stripline in the stripline adapter layer is interconnected with the common port of the ring separator component of the ring separator-filter assembly; the third port of the stripline is interconnected with the input port of the ring separator component of the ring separator-filter assembly; the fourth port of the stripline is interconnected with the output port of the ring separator component of the ring separator-filter assembly; and the fifth and sixth ports of the stripline are both interconnected with the interface of the SMP coaxial connector.

[0011] In one embodiment, prepregs exist between the layers of the first radiating patch, the first PMI foam, the second radiating patch, the second PMI foam, the H-type coupling gap, the stripline feed layer, the coaxial adapter and shielding post, and the stripline adapter layer. These layers are laminated together to form a printed circuit board (PCB). The annular filter assembly is soldered onto the PCB using an SMT reflow soldering process. The PCB is then integrated with a metal substrate using conductive adhesive via hot pressing. The annular filter assembly is placed within the metal substrate. Finally, the SMP coaxial connector is screwed onto the metal substrate using a clamping process.

[0012] In one embodiment, the ring-isolation-filter component is a circulator or isolator that integrates bandpass filtering function. The ring-isolation-filter component includes a ring-isolation component common port, a ring-isolation component output port, and a ring-isolation component input port. The ring-isolation component common port is the radio frequency port of the antenna. The ring-isolation component output port and the ring-isolation component input port are electrically connected to the SMP coaxial connector through two striplines in the stripline adapter layer.

[0013] In one embodiment, both the first layer of PMI foam and the second layer of PMI foam are composed of PMI foam material with a relative permittivity between 1.08 and 1.14.

[0014] In one embodiment, the metal substrate is provided with a reserved window and a through hole; the ring-isolator-filter assembly is accommodated in the reserved window, and the SMP coaxial connector is installed in the through hole by means of threads.

[0015] In one embodiment, the end of the stripline in the stripline feed layer is in the form of an open-circuit terminal, and is electromagnetically coupled to the first layer radiating patch and the second layer radiating patch through the H-shaped coupling gap.

[0016] A second aspect of the present invention provides an antenna array comprising a plurality of the aforementioned lightweight ultrawideband low-profile filter antennas, wherein the plurality of filter antennas are periodically arranged in a rectangular array.

[0017] A third aspect of the present invention provides a method for fabricating a lightweight ultra-wideband low-profile filter antenna, which includes the following steps: S1. Prepare a metal substrate as a support and shield. Mill a reserved window for accommodating the ring-block filter component in the mapping area between the metal substrate and the array element. Mill through holes for screw-on SMP coaxial connectors in the corresponding areas of the fifth port and sixth port of the stripline in the metal substrate and the stripline transition layer. S2. Take two RA300B copper clad laminates with a relative permittivity of 2.94 and thicknesses of 6.5 mil and 20 mil respectively. Etch an H-shaped gap on the upper surface of the 6.5 mil thick copper clad laminate and completely etch away the copper clad layer on the lower surface to form an H-shaped coupling gap. Etch a stripline with a characteristic impedance of 50 ohms on the upper surface of the 20 mil thick copper clad laminate. One end of the stripline is connected to the port of the stripline adapter layer through a coaxial adapter, and the other end is an open circuit, which is orthogonal to the position of the H-shaped coupling gap. S3. Take two more RA300B copper clad laminates with a relative permittivity of 2.94 and thicknesses of 3.5mil and 6.5mil respectively. Completely etch away the copper layer on the lower surface of the 3.5mil thick copper clad laminate, and simultaneously etch three striplines on the upper surface of the 6.5mil thick copper clad laminate. The second, third, fourth, fifth and sixth ports of the striplines are all led out from the lower surface of the copper clad laminate through a coaxial structure and have pads. S4. Place a prepreg of about 0.1 mm thickness between the above four copper-clad laminates, then press them together, and process the coaxial adapter and shielding post by drilling metal through holes and back drilling, thus forming the antenna feeding structure. S5. Next, the radiating part is processed: a rigid foam material with a thickness of 1.4 mm and a dielectric constant of approximately 1.13 is covered on the H-shaped coupling gap to form a second layer of PMI foam; a thin dielectric plate is placed on top of this foam layer, and the corresponding radiating patch pattern is etched on it to form the second layer of radiating patch; a layer of the same type of foam material with a thickness of 1.0 mm is then covered on top of this radiating patch to form the first layer of PMI foam; then, a thin dielectric plate is placed on top of the first layer of PMI foam, and the corresponding radiating patch pattern is etched on it to form the first layer of radiating patch. Semi-cured sheets are also placed between the above materials, and a foam-dielectric-patch-foam-dielectric-patch structure is formed by lamination. This structure is then laminated with the feed structure below to form a complete antenna printed circuit board. The processed antenna printed circuit board is then pressed together with the metal substrate through a hot pressing process. S6. Then, integrate the ring-block filter component: Select a custom SMT packaged ring-block filter component with a working frequency band covering 12-18GHz, in-band insertion loss less than 0.5dB, and out-of-band rejection greater than 40dB; print solder paste on the pads corresponding to the second, third, and fourth ports of the stripline on the bottom surface of the stripline transition layer; place the ring-block filter component in the reserved window of the metal substrate; align the common port, output port, and input port of the ring-block component with the pads of the above ports; and perform leaded reflow soldering on the entire antenna structure through an SMT reflow oven to maintain electrical connection with the stripline transition layer. S7. Finally, the SMP coaxial connector is screwed into the through hole of the metal substrate and electrically connected to the fifth and sixth ports of the stripline. The stripline adapter layer enables electrical connection with the input and output ports of the ring-block filter component. The other end of the SMP coaxial connector serves as the transmit / receive port of the antenna, enabling interconnection with the back-end TR component.

[0018] In one embodiment, in step S1, the material of the metal substrate is aluminum alloy or copper, and the surface of the metal substrate is silver-plated.

[0019] The beneficial effects of this invention are as follows: 1. Ultra-wideband characteristics: Employing a radiating structure of "low dielectric foam dielectric + double-layer patch". The foam dielectric effectively reduces stored energy, significantly lowering the antenna's Q value, thus providing broadband potential. The double-layer patch, by optimizing the size and spacing of the two layers, allows for a reasonable distribution and overlap of resonant points, ultimately forming a continuous and flat wide impedance bandwidth in the 12-18 GHz range. This lightweight ultra-wideband low-profile filter antenna disclosed in this invention is not limited to the Ku band but is also applicable to other frequency bands.

[0020] 2. High Gain and Excellent Radiation Pattern: The H-type slot-coupled feeding method effectively isolates the feeding network from the radiating part, reducing the distortion of the antenna radiation pattern caused by feed line radiation and ensuring good symmetry and unit beamwidth in both the H-plane and E-plane. Simultaneously, the double-layer patch structure effectively increases the antenna's aperture, contributing to improved antenna gain.

[0021] 3. Excellent filtering and out-of-band rejection performance: The ring-block filter component integrated through SMT technology brings the filtering function forward to the antenna port. This integrated transceiver design avoids the insertion loss and impedance mismatch problems caused by traditional discrete component cascading, and eliminates the need to integrate switching devices into the TR component, reducing the design complexity of the TR component. In addition, the bandpass characteristics of the ring-block component directly filter the signals entering the antenna, allowing only signals within the 12-18GHz frequency band to pass through and radiate efficiently, achieving excellent out-of-band rejection.

[0022] 4. High Integration and Process Reliability: The integration of the entire antenna printed circuit board with the metal substrate employs multi-layer lamination and hot-pressing processes, resulting in high mechanical strength and structural stability. The ring-spacing components are integrated using standard SMT reflow soldering, achieving high-density three-dimensional integration of the microwave components. The metal substrate provides excellent heat dissipation channels and electromagnetic shielding. This design is ideal for modular and array-based applications, aligning with the modern trend towards miniaturization and high reliability in electronic devices.

[0023] 5. High design flexibility: Key parameters such as the antenna's center frequency, bandwidth, and gain can be flexibly optimized by adjusting the size of the H-slot, the size and spacing of the two radiating patches, and the thickness of the foam layer. The selection of the ring-shaped isolation component can also be adjusted according to specific out-of-band suppression requirements, offering a high degree of design freedom. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a three-dimensional exploded view of a lightweight ultrawideband low-profile filter antenna according to the present invention.

[0026] Figure 2 This is a schematic diagram of the port of the stripline adapter layer of the present invention.

[0027] Figure 3 This is a schematic diagram of the port of the ring-isolation filter component of the present invention.

[0028] Figure 4 This is a simulation result curve of the voltage standing wave ratio (VSWR) of one embodiment of the present invention.

[0029] Figure 5 This is a simulation result of the gain versus frequency curve of one embodiment of the present invention.

[0030] Figure 6 This is a simulation result of the E-plane radiation pattern at a center frequency of 15 GHz, according to an embodiment of the present invention.

[0031] Figure 7 This is a simulation result of the H-plane radiation pattern at a center frequency of 15 GHz, according to an embodiment of the present invention.

[0032] Reference numerals: 1. First radiating patch; 2. First PMI foam layer; 3. Second radiating patch; 4. Second PMI foam layer; 5. H-type coupling gap; 6. Stripline feed layer; 7. Coaxial adapter and shielding post; 8. Stripline adapter layer; 8a. First port of stripline; 8b. Second port of stripline; 8c. Third port of stripline; 8d. Fourth port of stripline; 8e. Fifth port of stripline; 8f. Sixth port of stripline; 9. Ring separator-filter assembly; 9a. Common port of ring separator assembly; 9b. Output port of ring separator assembly; 9c. Input port of ring separator assembly; 10. Metal substrate; 10a. Reserved window; 10b. Through hole; 11. SMP coaxial connector. Detailed Implementation

[0033] To make the technical problems, technical solutions, and technical effects of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0035] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0036] In the description of the embodiments of the present invention, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0037] Example 1 like Figures 1 to 3As shown, this embodiment provides a lightweight ultra-wideband low-profile filter antenna, which includes, from top to bottom, a first radiating patch 1, a first PMI foam 2, a second radiating patch 3, a second PMI foam 4, an H-type coupling slot 5, a stripline feed layer 6, a coaxial adapter and shielding post 7, a stripline adapter layer 8, a ring-block filter assembly 9, a metal substrate 10, and an SMP coaxial connector 11; The first radiating patch 1 and the second radiating patch 3 are copper-clad boards with the lower copper clad layer etched away. The upper copper clad layer of the first radiating patch 1 and the second radiating patch 3 is processed with a rectangular radiating patch pattern. The first radiating patch 1 and the second radiating patch 3 are respectively pressed together with the first PMI foam 2 and the second PMI foam 4 to form the radiating part of the antenna. H-type coupling slot 5 is a copper-clad board with the lower copper layer etched away. Several H-type slot structures are provided on the upper copper layer of H-type coupling slot 5. Each slot structure corresponds orthogonally to one end of the two branches of the stripline of the stripline feed layer 6. The other end of the stripline of the stripline feed layer 6 corresponds to a stripline port of the stripline adapter layer 8 through the coaxial adapter and shielding post 7. Some stripline ports of the stripline adapter layer 8 are interconnected with the corresponding ports of the ring isolation-filter component. Some stripline ports of the stripline adapter layer 8 are interconnected with the interface of the SMP coaxial connector 11.

[0038] The stripline transition layer 8 includes a first stripline port 8a, a second stripline port 8b, a third stripline port 8c, a fourth stripline port 8d, a fifth stripline port 8e, and a sixth stripline port 8f. The other end of the stripline of the stripline feed layer 6 corresponds to the first port 8a of the stripline of the stripline transition layer 8 via a coaxial adapter and shielding post 7. The second port 8b of the stripline of the stripline adapter layer 8 is interconnected with the common port 9a of the ring isolation component of the ring isolation-filter component 9; the third port 8c of the stripline is interconnected with the input port 9c of the ring isolation component of the ring isolation-filter component 9; the fourth port 8d of the stripline is interconnected with the output port 9b of the ring isolation component of the ring isolation-filter component 9; and the fifth port 8e and the sixth port 8f of the stripline are both interconnected with the interface of the SMP coaxial connector 11.

[0039] In one embodiment, there are prepregs between the layers of the first radiating patch 1, the first PMI foam 2, the second radiating patch 3, the second PMI foam 4, the H-type coupling gap 5, the stripline feed layer 6, the coaxial adapter and shielding post 7, and the stripline adapter layer 8. The layers are laminated together to form a printed circuit board. The ring-isolator-filter component 9 is soldered onto the printed circuit board using an SMT reflow soldering process. The printed circuit board is integrated with the metal substrate 10 using conductive adhesive through hot pressing. The ring-isolator-filter component 9 is placed in the metal substrate 10. The SMP coaxial connector 11 is screwed onto the metal substrate 10 using a clamping process.

[0040] The ring-isolation-filter component 9 is a circulator or isolator that integrates bandpass filtering function. The ring-isolation-filter component 9 includes a ring-isolation component common port 9a, a ring-isolation component output port 9b, and a ring-isolation component input port 9c. The ring-isolation component common port 9a is the RF port of the antenna. The ring-isolation component output port 9b and the ring-isolation component input port 9c are electrically connected to the SMP coaxial connector 11 through two striplines in the stripline adapter layer 8.

[0041] The first layer of PMI foam 2 and the second layer of PMI foam 4 are both composed of PMI foam material with a relative permittivity between 1.08 and 1.14.

[0042] The metal substrate 10 has a reserved window 10a and a through hole 10b; the ring-isolator-filter assembly 9 is housed in the reserved window 10a, and the SMP coaxial connector 11 is installed in the through hole 10b by means of threads.

[0043] In one embodiment, the ends of the striplines in the stripline feed layer 6 are in the form of open-circuit terminals, and are electromagnetically coupled to the first radiating patch 1 and the second radiating patch 3 through the H-type coupling gap 5.

[0044] Example 2 This embodiment provides an antenna array, including multiple lightweight ultra-wideband low-profile filter antennas as disclosed in Embodiment 1, wherein the multiple filter antennas are periodically arranged in a rectangular array.

[0045] Example 3 This embodiment provides a method for fabricating a lightweight ultrawideband low-profile filter antenna, including the following steps: S1. Prepare a metal substrate 10 as a support and shield. The material of the metal substrate 10 can be aluminum alloy or copper, and the surface is silver-plated. A reserved window 10a for accommodating the ring-isolation filter component 9 is milled in the area of ​​the metal substrate 10 and the array element mapping area. Through holes 10b for screw-mounting SMP coaxial connector 11 are milled in the corresponding areas of the metal substrate 10 and the fifth port 8e and the sixth port 8f of the stripline of the stripline transition layer 8. S2. Take two RA300B copper clad laminates with a relative permittivity of 2.94 and thicknesses of 6.5 mil and 20 mil respectively. Etch an H-shaped gap on the upper surface of the 6.5 mil thick copper clad laminate and completely etch away the copper clad layer on the lower surface to form an H-shaped coupling gap 5. Etch a stripline with a characteristic impedance of 50 ohms on the upper surface of the 20 mil thick copper clad laminate. One end of the stripline is connected to port 8a of the stripline adapter layer 8 through a coaxial adapter, and the other end is an open circuit, which is orthogonal to the position of the H-shaped coupling gap 5. S3. Take two more RA300B copper clad laminates with a relative permittivity of 2.94 and thicknesses of 3.5mil and 6.5mil respectively. Completely etch away the copper layer on the lower surface of the 3.5mil thick copper clad laminate, and simultaneously etch three strip lines on the upper surface of the 6.5mil thick copper clad laminate. The second port 8b, the third port 8c, the fourth port 8d, the fifth port 8e, and the sixth port 8f of the strip lines are all led out from the lower surface of the copper clad laminate through a coaxial structure and have pads. S4. A semi-cured sheet of about 0.1 mm thickness is placed between the above 4 copper-clad boards, and then they are pressed together. The coaxial adapter and shielding post 7 are processed by drilling metal through holes and back drilling, thus forming the antenna feeding structure. S5. Next, the radiating part is processed: a rigid foam material with a thickness of 1.4 mm and a dielectric constant of about 1.13 is covered on the H-type coupling gap 5 to form the second layer of PMI foam 4; a thin dielectric plate is placed on top of this foam layer, and the corresponding radiating patch pattern is etched on it to form the second layer of radiating patch 3; a layer of the same foam material with a thickness of 1.0 mm is then covered on top of this radiating patch to form the first layer of PMI foam 2; then, a thin dielectric plate is placed on top of the first layer of PMI foam 2, and the corresponding radiating patch pattern is etched on it to form the first layer of radiating patch 1. Semi-cured sheets are also placed between the above materials, and a foam-dielectric-patch-foam-dielectric-patch structure is formed by lamination. This structure is then laminated with the feed structure below to form a complete antenna printed circuit board. The processed antenna printed circuit board is then pressed together with the metal substrate 10 by hot pressing. S6. Then, integrate the ring-block filter component 9: Select a customized SMT packaged ring-block filter component 9 with a working frequency band covering 12-18GHz, in-band insertion loss less than 0.5dB, and out-of-band rejection greater than 40dB; print solder paste on the pads corresponding to the second port 8b, third port 8c, and fourth port 8d of the stripline on the bottom surface of the stripline transition layer 8; place the ring-block filter component 9 in the reserved window 10a of the metal substrate 10; align the common port 9a, output port 9b, and input port 9c of the ring-block component with the pads of the aforementioned ports; and perform leaded reflow soldering on the entire antenna structure through an SMT reflow oven to maintain electrical connection with the stripline transition layer 8. S7. Finally, the SMP coaxial connector 11 is screwed into the through hole 10b of the metal substrate 10 and electrically connected to the fifth port 8e and the sixth port 8f of the stripline. Electrical connection with the ring isolation component input port 9c and the ring isolation component output port 9b of the ring isolation-filter component 9 is achieved through the stripline adapter layer 8. The other end of the SMP coaxial connector 11 serves as the transmit / receive port of the antenna, realizing interconnection with the back-end TR component.

[0046] Figure 4 The graph shows the simulation results of the antenna's voltage standing wave ratio (VSWR). It can be seen from the graph that the antenna maintains a good standing wave ratio in the frequency range of 12GHz to 18GHz. Figure 5 The figure shows the simulation results of the antenna's frequency gain variation curve. It can be seen from the figure that its gain basically corresponds to the standing wave.

[0047] Figure 6 , Figure 7 The figures show the simulation results of the antenna's radiation pattern in the E-plane and H-plane at a center frequency of 15 GHz, respectively. As can be seen from the figures, the antenna's radiation pattern has good symmetry.

Claims

1. A lightweight, ultra-wideband, low-profile filter antenna, characterized in that, The first layer of radiating patch (1), the first layer of PMI foam (2), the second layer of radiating patch (3), the second layer of PMI foam (4), the H-type coupling gap (5), the stripline feed layer (6), the coaxial adapter and shielding post (7), the stripline adapter layer (8), the ring-block filter assembly (9), the metal substrate (10), and the SMP coaxial connector (11) are arranged sequentially from top to bottom. The first radiating patch (1) and the second radiating patch (3) are copper-clad boards with the lower copper clad layer etched away. The upper copper clad layer of the first radiating patch (1) and the second radiating patch (3) is processed with a rectangular radiating patch pattern. The first radiating patch (1) and the second radiating patch (3) are respectively pressed together with the first PMI foam (2) and the second PMI foam (4) to form the radiating part of the antenna. The H-type coupling gap (5) is a copper-clad board with the lower copper layer etched away. Several H-type gap structures are provided on the upper copper layer of the H-type coupling gap (5). Each gap structure corresponds orthogonally to one end of the two branches of the stripline of the stripline feed layer (6). The other end of the stripline of the stripline feed layer (6) corresponds to one stripline port of the stripline adapter layer (8) through the coaxial adapter and shielding post (7). Some stripline ports of the stripline adapter layer (8) are interconnected with the corresponding ports of the ring isolation-filter component. Some stripline ports of the stripline adapter layer (8) are interconnected with the interface of the SMP coaxial connector (11).

2. The lightweight ultra-wideband low-profile filter antenna according to claim 1, characterized in that, The stripline transition layer (8) includes a first stripline port (8a), a second stripline port (8b), a third stripline port (8c), a fourth stripline port (8d), a fifth stripline port (8e), and a sixth stripline port (8f). The other end of the stripline of the stripline feed layer (6) corresponds to the first port (8a) of the stripline of the stripline transition layer (8) via the coaxial adapter and shielding post (7); The second port (8b), the third port (8c), and the fourth port (8d) of the stripline are interconnected with each port of the ring-isolation filter component (9), and the fifth port (8e) and the sixth port (8f) of the stripline are interconnected with the interface of the SMP coaxial connector (11).

3. The lightweight ultra-wideband low-profile filter antenna according to claim 1, characterized in that, There are prepregs between the layers of the first layer radiating patch (1), the first layer PMI foam (2), the second layer radiating patch (3), the second layer PMI foam (4), the H-type coupling gap (5), the stripline feed layer (6), the coaxial adapter and shielding post (7), and the stripline adapter layer (8). The layers are laminated into a printed circuit board using lamination technology. The ring-isolator-filter component (9) is soldered onto the printed circuit board using SMT reflow soldering process. The printed circuit board is integrated with the metal substrate (10) using conductive adhesive through hot pressing. The ring-isolator-filter component (9) is placed in the metal substrate (10). The SMP coaxial connector (11) is screwed onto the metal substrate (10) using clamping process.

4. A lightweight ultra-wideband low-profile filter antenna according to claim 2, characterized in that, The ring-isolator-filter component (9) is a circulator or isolator that integrates bandpass filtering function. The ring-isolator-filter component (9) includes a ring-isolator common port (9a), a ring-isolator output port (9b), and a ring-isolator input port (9c). The ring-isolator common port (9a) is the radio frequency port of the antenna. The second port (8b) of the stripline is connected to the ring-isolator common port (9a). The ring-isolator output port (9b) and the ring-isolator input port (9c) are electrically connected to the SMP coaxial connector (11) through two striplines in the stripline adapter layer (8).

5. A lightweight ultra-wideband low-profile filter antenna according to claim 1, characterized in that, Both the first layer of PMI foam (2) and the second layer of PMI foam (4) are made of PMI foam material with a relative permittivity between 1.08 and 1.

14.

6. A lightweight ultra-wideband low-profile filter antenna according to claim 1, characterized in that, The metal substrate (10) is provided with a reserved window (10a) and a through hole (10b); the ring-filter assembly (9) is accommodated in the reserved window (10a), and the SMP coaxial connector (11) is installed in the through hole (10b) by means of threads.

7. A lightweight ultra-wideband low-profile filter antenna according to claim 1, characterized in that, The end of the stripline in the stripline feed layer (6) is in the form of an open circuit, and is electromagnetically coupled to the first layer radiating patch (1) and the second layer radiating patch (3) through the H-type coupling gap (5).

8. An antenna array, characterized in that, It includes a plurality of lightweight ultrawideband low-profile filter antennas as described in any one of claims 1 to 7, wherein the plurality of filter antennas are periodically arranged in a rectangular array.

9. A method for fabricating a lightweight ultra-wideband low-profile filter antenna, used to fabricate a lightweight ultra-wideband low-profile filter antenna as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1. Prepare a metal substrate (10) as a support and shield. Mill a reserved window (10a) for accommodating the ring-filter component (9) in the metal substrate (10) and the array element mapping area. Mill through holes (10b) for screwing in the SMP coaxial connector (11) in the corresponding areas of the metal substrate (10) and the fifth port (8e) and sixth port (8f) of the stripline of the stripline transition layer (8). S2. Take two RA300B copper-clad laminates with a relative permittivity of 2.94 and thicknesses of 6.5mil and 20mil respectively. Etch an H-shaped gap on the upper surface of the 6.5mil thick copper-clad laminate and completely etch away the copper layer on the lower surface to form an H-shaped coupling gap (5). Etch a stripline with a characteristic impedance of 50 ohms on the upper surface of the 20mil thick copper-clad laminate. One end of the stripline is connected to the port (8a) of the stripline adapter layer (8) through a coaxial adapter, and the other end is an open circuit and is orthogonally corresponding to the position of the H-shaped coupling gap (5). S3. Take two more RA300B copper clad laminates with a relative permittivity of 2.94 and thicknesses of 3.5mil and 6.5mil respectively. Completely etch away the copper layer on the lower surface of the 3.5mil thick copper clad laminate, and simultaneously etch three strip lines on the upper surface of the 6.5mil thick copper clad laminate. The second port (8b), third port (8c), fourth port (8d), fifth port (8e), and sixth port (8f) of the strip lines are all led out from the lower surface of the copper clad laminate through a coaxial structure and have pads. S4. Place a semi-cured sheet of about 0.1 mm thickness between the above four copper-clad boards, then press them together, and process the coaxial adapter and shielding post (7) by drilling metal through holes and back drilling process, thereby forming the antenna feeding structure. S5. Next, the radiating part is processed: a rigid foam material with a thickness of 1.4 mm and a dielectric constant of about 1.13 is covered on the H-type coupling gap (5) to form a second layer of PMI foam (4); a thin dielectric plate is placed on top of the foam layer, and the corresponding radiating patch pattern is etched on it to form a second layer of radiating patch (3); a layer of the same foam material with a thickness of 1.0 mm is covered on top of the radiating patch to form a first layer of PMI foam (2); then, a thin dielectric plate is placed on top of the first layer of PMI foam (2), and the corresponding radiating patch pattern is etched on it to form a first layer of radiating patch (1). Semi-cured sheets are also placed between the above materials, and a foam-dielectric-patch-foam-dielectric-patch structure is formed by lamination. This structure is then laminated with the feed structure below to form a complete antenna printed circuit board. The processed antenna printed circuit board and the metal substrate (10) are then pressed together by hot pressing. S6. Then, the ring-block filter component (9) is integrated: a custom SMT packaged ring-block filter component (9) is selected, whose working frequency band covers 12-18GHz, in-band insertion loss is less than 0.5dB, and out-of-band rejection is greater than 40dB; solder paste is printed on the pads corresponding to the second port (8b), third port (8c), and fourth port (8d) of the stripline on the bottom surface of the stripline transition layer (8), the ring-block filter component (9) is placed in the reserved window (10a) of the metal substrate (10), and the common port (9a), output port (9b), and input port (9c) of the ring-block component are aligned with the pads of the above ports respectively. The entire antenna structure is then reflow soldered with lead in an SMT reflow oven to keep it electrically connected to the stripline transition layer (8); S7. Finally, the SMP coaxial connector (11) is screwed into the through hole (10b) of the metal substrate (10) and electrically connected to the fifth port (8e) and the sixth port (8f) of the stripline. The stripline adapter layer (8) realizes the electrical connection with the ring isolation component input port (9c) and the ring isolation component output port (9b) of the ring isolation-filter component (9). The other end of the SMP coaxial connector (11) serves as the transmit and receive port of the antenna, realizing interconnection with the back-end TR component.

10. The method for fabricating a lightweight ultra-wideband low-profile filter antenna according to claim 9, characterized in that, In step S1, the material of the metal substrate (10) is aluminum alloy or copper, and the surface of the metal substrate (10) is silver plated.

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