Dual-frequency common-caliber broadband circularly polarized antenna array

Abstract

According to the dual-frequency common-caliber broadband circularly polarized antenna array, a high-frequency antenna unit and a low-frequency antenna unit are stacked up and down, a layer of high-frequency feed network board is clamped between the high-frequency antenna unit and the low-frequency antenna unit, and a certain gap is formed in the high-frequency feed network board, so that common-caliber installation of the antenna units of two frequency bands can be realized in a limited space; the two can work normally; meanwhile, a microstrip antenna unit structure based on a feed balun design is provided, and compared with a common air microstrip antenna, the working bandwidth of the antenna is expanded, and meanwhile the antenna is well fixed to be installed and supported. The antenna array adopts a conformal integrated design, the size is greatly reduced, the engineering property is high, the antenna array is convenient to assemble and use, and the requirement of a mobile communication system on a new generation of phased-array antennas can be well met.

Description

Technical Field

[0001] This utility model relates to the field of antenna technology in electronic communication, and particularly to a dual-frequency common-aperture broadband circularly polarized antenna array in the fields of satellite communication and microwave communication. Background Technology

[0002] The rapid development of satellite communications has led to the rapid development of antennas used in satellite communication and data transmission systems, resulting in a surge in demand for various antennas and placing higher requirements on them. In vehicle-mounted, airborne, and shipborne satellite communication systems, antennas often need to possess characteristics such as good polarization, high gain, strong directivity, multi-bandwidth, high integration, and wide bandwidth to increase the data rate of satellite communication. Specifically: good polarization refers to high polarization purity and good polarization matching between the receiving and transmitting antennas. In commercial satellite communication systems, the signals received and transmitted by the satellite are circularly polarized waves, so regardless of the angle between the radar and the satellite, no cross-polarization components will occur. In other words, satellite receiving and transmitting circularly polarized waves will not cause polarization mismatch, thus preventing a decrease in data transmission efficiency. High gain and strong directivity mean that the maximum system gain can be obtained within a limited antenna area, thereby improving the system's G / T value. Multi-bandwidth and high integration refer to the increasing demand in the satellite communication field for simultaneous multi-band satellite communication with multi-time division multiplexing (MTD). This means that a single antenna array should meet the communication requirements of multiple frequency bands, with high integration for ease of use. Bandwidth refers to the data rate of satellite communication by widening the real-time receiving frequency band. In other words, the antenna gain bandwidth should be wider to enable real-time reception.

[0003] However, while commonly used reflector antennas in satellite communications offer high gain and strong directivity, they are costly, bulky, and difficult to integrate across multiple frequency bands, making them particularly inconvenient in mobile communications. In common antenna designs, the effective aperture is limited by the antenna's scanning volume. For a given scanning volume, low-profile antennas can achieve the highest system gain, and most low-profile antennas are microstrip antennas. However, existing microstrip antenna structures have narrow bandwidths, making them unsuitable for increasingly demanding frequency requirements. Common methods for extending the bandwidth of microstrip antennas include: using low-dielectric-constant substrates, increasing substrate thickness, using coupled feeding, and employing multilayer structures. The first two methods offer limited bandwidth increases, typically up to an 8% increase. The latter two methods provide wider bandwidths but are structurally complex and costly.

[0004] Therefore, with the rapid development of satellite communication technology, how to design a multi-frequency common aperture broadband circularly polarized antenna array that is simple in structure, easy to install, durable, suitable for multi-band use, highly integrated, has a wide frequency band and good antenna efficiency has become an important issue in satellite communication technology. Summary of the Invention

[0005] This disclosure provides a dual-frequency common-aperture broadband circularly polarized antenna array, which can well meet the requirements of mobile communication systems for next-generation satellite communication antennas.

[0006] The dual-frequency common-aperture broadband circularly polarized antenna array disclosed herein includes:

[0007] Antenna radome, multiple high-frequency antenna units, multiple high-frequency feed network boards, feed network cavity, multiple low-frequency antenna units, multiple low-frequency feed network boards, and multiple RF connectors.

[0008] The multiple high-frequency antenna units are soldered onto the high-frequency feed network board for transmitting signals with a higher center frequency; the multiple low-frequency antennas are located below the high-frequency feed network board and are also soldered onto the low-frequency feed network board for transmitting signals with a lower center frequency.

[0009] Among them, the high- and low-frequency antennas use air as the microstrip antenna medium, and the feed point and the radiating patch are set as a gradient balun structure to improve the antenna's operating bandwidth.

[0010] The high and low frequency feed network board is fabricated using PCB board. The front side has a large area of ​​copper-plated windows to serve as a reflective surface for antenna radiation. A microstrip feed network is used to realize the functions of left and right circular polarization of the antenna and antenna element synthesis.

[0011] Meanwhile, the high-frequency feed network board has a certain metal gap in the middle of the metal surface to provide radiation space for the low-frequency antenna, so that the signal transmission of the low-frequency antenna unit and the high-frequency antenna unit are less affected.

[0012] RF connectors are used to connect antenna units to the back-end RF network, and to protect and fix the antenna in the radome and network board structure cavity.

[0013] This dual-frequency common-aperture broadband circularly polarized antenna array features a wide antenna frequency band, simple antenna structure, and high integration, which can well meet the requirements of mobile communication systems for next-generation satellite communication antennas.

[0014] Compared with the prior art, the beneficial effects of this disclosure are: (1) The high-frequency antenna unit and the low-frequency antenna unit are stacked on top of each other, with a high-frequency feed network board sandwiched in the middle. By opening a certain gap on the high-frequency feed network board, the antenna units of the two frequency bands can be installed in a limited space with the same aperture, and both can work normally; (2) A new microstrip antenna unit structure is proposed. The antenna unit structure is composed of a radiating patch, a feed balun, and a feed point. Compared with the common air microstrip antenna, the feed balun design expands the antenna working bandwidth and also provides good fixation for antenna installation; (3) The processing technology is simple and the cost is low; (4) Air is used as the dielectric layer, which has the lowest dielectric constant; (5) The overall antenna array adopts a conformal integrated design, which greatly compresses the size and has strong engineering performance; (6) It is easy to assemble and use, and can well meet the requirements of mobile communication systems for the next generation of phased array antennas. Attached Figure Description

[0015] The above and other objects, features and advantages of this disclosure will become more apparent from the more detailed description of exemplary embodiments of this disclosure taken in conjunction with the accompanying drawings, in which the same reference numerals generally represent the same components.

[0016] Figure 1 A three-dimensional structural diagram of an exemplary embodiment of a dual-frequency common-aperture broadband circularly polarized antenna array;

[0017] Figure 2 A schematic diagram of a distributed three-dimensional structure as an exemplary embodiment;

[0018] Figure 3 A schematic diagram of a side-view distributed structure for an exemplary embodiment;

[0019] Figure 4 This is a schematic diagram of a high- and low-frequency antenna unit as an exemplary embodiment.

[0020] Figure 5 The gain curve of the high-frequency antenna element in the exemplary embodiment;

[0021] Figure 6 The axial ratio curve of the high-frequency antenna element in the exemplary embodiment;

[0022] Figure 7 The gain curve of the low-frequency antenna element in the exemplary embodiment;

[0023] Figure 8 The axial ratio curve of the low-frequency antenna element in the exemplary embodiment;

[0024] Figure 9 Schematic diagram of a high- and low-frequency power supply network board as an exemplary embodiment;

[0025] Figure 10The radiation pattern curve of the high-frequency antenna array in the exemplary embodiment;

[0026] Figure 11 The radiation pattern curve of the low-frequency antenna array in the exemplary embodiment;

[0027] In the figure, 1 is radome 1; 2 is high-frequency antenna element; 3 is high-frequency feed network board; 4 is feed network cavity; 5 is low-frequency antenna element; 6 is RF connector; 7 is low-frequency feed network board; 8 is dual-frequency common aperture broadband circularly polarized antenna array.

[0028] a1 is radiating plate 1; a2 is feeding balun 1; a3 is feeding point 1;

[0029] b1 is mounting hole 1; b2 is reflective floor 1; b3 is radiation gap; b4 is high-frequency power supply network;

[0030] c1 is the network clearance slot 1; c2 is the mounting hole 2;

[0031] d1 is the mounting hole 3; d2 is the network clearance slot 2; d3 is the radiating plate 2; d4 is the feed balun 2; d5 is the feed point 2;

[0032] e1 is the power supply pin; e2 is the central dielectric; e3 is the outer shell structure;

[0033] f1 is the mounting hole; f2 is the surface mount connector; f3 is the reflector ground plane 2; f4 is the low frequency power supply network circuit. Detailed Implementation

[0034] Preferred embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0035] This disclosure provides a dual-band common-aperture broadband circularly polarized antenna array. The exemplary overall structure of the dual-band common-aperture broadband circularly polarized antenna array according to this disclosure is shown in the attached figure. Figure 1-3 As shown, where:

[0036] The dual-band common-aperture broadband circularly polarized antenna array 8 includes: radome 1, sixty-four high-frequency antenna elements 2, four high-frequency feed network boards 3, feed network cavity 4, four low-frequency antenna elements 5, four low-frequency feed network boards 6, and sixteen radio frequency connectors 7.

[0037] Figure 1 This is a schematic diagram of a three-dimensional structure; Figure 2 This is a schematic diagram of a dispersed three-dimensional structure; Figure 3This is a schematic diagram of a side-view dispersed structure.

[0038] It is understandable that the frequency bands corresponding to the four low-frequency antenna elements 5 are distinct from the frequency bands corresponding to the sixty-four high-frequency antenna elements 1:

[0039] In some implementations, the four low-frequency antenna elements 5 correspond to the same frequency band; the sixty-four high-frequency antenna elements 1 correspond to the same frequency band. That is, the four low-frequency antenna elements 5 are the same, corresponding to the same low-frequency band, and the sixty-four high-frequency antenna elements 1 are the same, corresponding to the same high-frequency band.

[0040] In other embodiments, the four low-frequency antenna elements 5 may correspond to different frequency bands; that is, the four low-frequency antenna elements 5 need not be the same and can correspond to multiple low-frequency bands (up to four). Similarly, the sixty-four high-frequency antenna elements 1 may correspond to different frequency bands; that is, the sixty-four high-frequency antenna elements 1 need not be the same and can correspond to multiple high-frequency bands (up to sixty-four). In this case, the dual-frequency common-aperture broadband circularly polarized antenna array of this disclosure can be understood as a multi-frequency common-aperture broadband circularly polarized antenna array. These multi-frequency common-aperture broadband circularly polarized antennas are divided into two groups: the group with lower frequency bands is processed by four low-frequency antenna elements 5, and the group with higher frequency bands is processed by sixty-four high-frequency antenna elements 1.

[0041] In this embodiment, sixty-four high-frequency antenna elements 2 and four low-frequency antenna elements 5 are stacked together, while ensuring that their array spacing is constant. That is, the spacing between the sixty-four high-frequency antenna elements 2 is constant, and the spacing between the four low-frequency antenna elements 5 is constant. Specifically, the array spacing between the sixty-four high-frequency antenna elements 2 is one-quarter of the array spacing between the four low-frequency antenna elements 5. A low-frequency antenna element 5 is placed below every 4×4 high-frequency antenna elements 2. An antenna cover 1 is provided on top of the sixty-four high-frequency antenna elements 2 to protect the antennas and ensure their performance safety.

[0042] See Figure 4 , Figure 4 This is a schematic diagram of the high- and low-frequency antenna units in this embodiment. The high-frequency antenna unit 2 is dual-port fed, consisting of a radiating plate 1a1, a feed balun 1a2, and a feed point 1a3, all integrated into a single unit using an all-metal processing method. The low-frequency antenna unit 5 is four-port fed, consisting of a radiating plate 2d3, a feed balun 2d4, and a feed point 2d5, also integrated into a single unit using an all-metal processing method. The radiating plate 2d3 is engraved with mounting holes 3d1 and network clearance slots 2d2 for the integrated installation of the antenna array.

[0043] See Figure 5 and Figure 6 , Figure 5This is the gain curve of the high-frequency antenna unit in this embodiment. Figure 6 This is the axial ratio curve of the high-frequency antenna element in this embodiment. It can be seen that, compared with a conventional microstrip antenna, the high-frequency antenna element 2 in this embodiment has significantly improved gain bandwidth and axial ratio bandwidth.

[0044] See Figure 7 and Figure 8 , Figure 7 This is the gain curve of the low-frequency antenna element in this embodiment. Figure 8 This is the axial ratio curve of the low-frequency antenna element in this embodiment. It can be seen that, compared with a conventional microstrip antenna, the low-frequency antenna element 5 in this embodiment has significantly improved gain bandwidth and axial ratio bandwidth.

[0045] Compared to existing technologies, the antenna structure in this embodiment uses air as the antenna medium, resulting in low dielectric loss. It also employs a graded balun structure, which, compared to conventional microstrip antennas, significantly improves gain bandwidth and axial ratio bandwidth by using a graded balun structure between the feed and radiating patch. The graded balun structure also provides a fixed support for the antenna's radiating surface, making it more practical for engineering applications. Furthermore, the radiating patch, feed balun, and feed point are integrated into a single unit, resulting in a simple, compact, and versatile structure that is easy to implement while significantly reducing costs.

[0046] See Figure 2 and Figure 9 , Figure 2 This is a schematic diagram of the dispersed three-dimensional structure in this embodiment. Figure 9 This is a schematic diagram of the high- and low-frequency feed network board in this embodiment. A high-frequency feed network board 3 and a feed network cavity board 4 are sandwiched between every 4×4 high-frequency antenna elements 2 and a single low-frequency antenna element 5. A low-frequency feed network board 6 is placed below each single low-frequency antenna element 5. Simultaneously, an RF connector 7 passes through the low-frequency feed network board 6, the low-frequency antenna elements 5, and the feed network cavity board 4, connecting to the high-frequency feed network board 3.

[0047] The low-frequency feed network board 6 consists of a reflective ground plane 2f3 and a low-frequency feed network f4. The reflective ground plane 2f3 is formed on a large area of ​​copper plating on the top surface of the low-frequency feed network board 6. The low-frequency feed network f4 is formed on a portion of copper plating on the bottom surface of the low-frequency feed network board 6 and is composed of microstrip lines on the bottom surface of the low-frequency feed network board 6. Meanwhile, for conformal and output requirements, the low-frequency feed network board 6 has mounting holes f1 and surface-mount connectors f2 for fixing the RF connector 7 and connecting it to the back-end RF network.

[0048] The high-frequency feed network board 3 consists of a reflective ground plane 1b2, a radiating slot b3, and a high-frequency feed network b4. The reflective ground plane 1b2 is formed on a large area of ​​copper plating on the top surface of the high-frequency feed network board. The radiating slot b3 is formed on the middle portion of the non-copper plating area on the two conductive metal layers on the two surface layers of the high-frequency feed network board. The high-frequency feed network b4 is formed on the two portions of copper plating on the two surface layers of the high-frequency feed network board and consists of microstrip lines on the two surface layers of the high-frequency feed network board 3.

[0049] The high-frequency power supply network board 3 is connected to the radio frequency connector 7, which consists of a power supply pin e1, a central dielectric e2, and a housing structure e3, and is used to connect high-frequency signals to the back-end radio frequency network.

[0050] In this embodiment, the wavelength of the electromagnetic wave from the low-frequency antenna element 5 is long enough to allow it to pass through the radiation gap b3 and the high-frequency antenna element 2, thus minimizing the impact of the low-frequency antenna element 5 on the high-frequency antenna element 2. Meanwhile, the high-frequency antenna element 2, located above the low-frequency antenna element 5 without obstruction, is also less affected by the low-frequency antenna element 5. This allows for effective multi-frequency radiation within a compact space.

[0051] See Figure 10 , Figure 10 This is the radiation pattern curve of the high-frequency antenna array in this embodiment. It can be seen that the dual-frequency common-aperture broadband circularly polarized antenna array 8 provided in this embodiment has a gain of 25.84 dB for the high-frequency antenna.

[0052] See Figure 11 , Figure 11 This is the radiation pattern curve of the low-frequency antenna array in this embodiment. It can be seen that the dual-frequency common-aperture broadband circularly polarized antenna array 8 provided in this embodiment has a gain of 20.27 dB for the low-frequency antenna.

[0053] Combination Figure 10 and Figure 11 The dual-frequency common-aperture broadband circularly polarized antenna array 8 provided in this embodiment has normal radiation performance for both frequency bands. It can realize that both low-frequency and high-frequency antennas can work normally under common aperture, and the antenna performance indicators are not affected.

[0054] See Figure 1 , Figure 1 This is a schematic diagram of the three-dimensional structure of this embodiment. It can be understood that the dual-frequency common-aperture broadband circularly polarized antenna array 8 is an overall square planar array, which is simple to expand. Depending on the needs of the actual application, several dual-frequency common-aperture broadband circularly polarized antenna arrays 8 can be used as several subarray units to expand into a larger array antenna.

[0055] In summary, in this embodiment, the high-frequency antenna unit 2 and the low-frequency antenna unit 5 are placed vertically, with the high-frequency antenna unit 2 above the low-frequency antenna unit 5. At the same time, a radiation gap b3 is opened in the middle of the high-frequency feed network board 3. This allows the high-frequency antenna unit 2 to work normally while the electromagnetic wave wavelength of the low-frequency antenna unit 5 is long enough to radiate outward through the radiation gap b3. The low-frequency antenna unit 5 is less affected by the high-frequency antenna unit 2, thus enabling dual-frequency radiation to be effectively achieved in a compact space.

[0056] This antenna array has a compact structure, strong versatility, is easy to implement, and has good antenna performance, making it suitable for large satellite communication antennas.

[0057] The above technical solutions are merely exemplary embodiments of this utility model. For those skilled in the art, based on the application methods and principles disclosed in this utility model, it is easy to make various types of improvements or modifications, and not limited to the methods described in the specific embodiments of this utility model. Therefore, the methods described above are only preferred and not restrictive.

Claims

1. A dual-frequency common-aperture broadband circularly polarized antenna array, characterized in that, include: Antenna radome, multiple high-frequency antenna elements, multiple high-frequency feed network boards, feed network cavities, multiple low-frequency antenna elements, multiple low-frequency feed network boards, and multiple RF connectors; among which: Multiple high-frequency antenna elements are soldered at equal intervals onto a high-frequency feed network board for transmitting signals with a high center frequency. Multiple low-frequency antenna elements are equally spaced below the high-frequency feed network board and simultaneously soldered onto the low-frequency feed network board for transmitting signals with a lower center frequency. Meanwhile, a dielectric gap is opened in the middle of the surface of the high-frequency feed network board to provide radiation space for the low-frequency antenna.

2. The antenna array according to claim 1, characterized in that, The spacing between each high-frequency antenna element array and the spacing between each low-frequency antenna element array are constant, and the spacing between the low-frequency antenna element arrays is an integer multiple of the spacing between the high-frequency antenna element arrays.

3. The antenna array according to claim 1, characterized in that, The high-frequency antenna unit includes: a first radiating plate, a first feeding balun, and a first feeding point, which are integrated into one unit. The first radiating plate is on the first feeding balun, the first feeding balun is on the first feeding point, and the first feeding point is soldered to the high-frequency feeding network of the high-frequency feeding network board in the form of dual-port direct feeding. The low-frequency antenna unit includes a second radiating plate, a second feed balun, and a second feed point, which are integrated into one unit. The second radiating plate is on the second feed balun, the second feed balun is on the second feed point, and the second feed point is soldered to the low-frequency feed network of the low-frequency feed network board in the form of direct four-port feeding.

4. The antenna array according to any one of claims 1-3, characterized in that: The frequency bands corresponding to each low-frequency antenna element may be the same or different; The frequency bands corresponding to each high-frequency antenna element may be the same or different.

5. The antenna array according to claim 4, characterized in that: The surface of the low-frequency antenna unit is engraved with a network clearance groove of a certain depth along the corresponding high-frequency network circuit to allow the high-frequency feed network circuit to run; at the same time, the low-frequency antenna unit is provided with mounting holes for antenna array integration and installation.

6. The antenna array according to claim 1, characterized in that: The high-frequency feed network board is waterproof and has an irregular rectangular shape; it includes: a first reflective ground plane, radiation gaps, and a high-frequency feed network; wherein: The first reflective ground plane is formed on a large area of ​​copper cladding on the top surface of the high-frequency feed network board; The high-frequency feed network is formed on the metal layers on the upper and lower surfaces of the high-frequency feed network board, and is composed of microstrip lines on the two surfaces of the high-frequency feed network board. The radiation gap is formed by the non-copper area in the middle part of the metal layer on the upper and lower surfaces of the high-frequency feed network board.

7. The antenna array according to claim 1, characterized in that: The low-frequency feed network board is rectangular and includes: a second reflector ground plane and a low-frequency feed network, wherein: The second reflective ground plane is formed on a large area of ​​copper cladding on the top surface of the low-frequency feed network board; The low-frequency feed network is formed on a conductive metal layer on the bottom surface of the low-frequency feed network board, and is composed of microstrip lines on the bottom surface of the low-frequency feed network board. In addition, the low-frequency feed network board is also provided with mounting holes in the middle for antenna array integration and installation; The low-frequency feed network board also has surface-mount connectors on part of the copper cladding on the bottom surface for connecting the low-frequency antenna signal to the back-end RF network.

8. The antenna array according to claim 1, characterized in that: The radome is located above the high-frequency antenna unit, is waterproof, and has an irregular rectangular shape. It is made of a material with a low dielectric constant.

9. The antenna array according to claim 1, characterized in that: The feed network cavity is formed by a metal structure located between the high-frequency antenna unit and the low-frequency antenna unit. The surface of the feed network cavity is engraved with network clearance grooves to allow the high-frequency feed network circuit to run, and mounting holes are provided for the integrated installation of the high-frequency antenna array.

10. The antenna array according to claim 1, characterized in that: The radio frequency connector is located under the low-frequency antenna unit, passes through the metal structure of the low-frequency antenna unit or network board structure cavity, and is connected to the high-frequency feed network board for connecting the high-frequency antenna signal to the back-end radio frequency network. The radio frequency connector includes: a metal housing, an intermediate dielectric, and a central metal pin.

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