Radome integrated array antenna unit and system

Abstract

The invention belongs to the technical field of antennas and microwaves, and discloses an antenna housing integrated array antenna unit and system. The antenna unit comprises a main shell, a parasitic patch layer, an auxiliary shell, a main patch layer, a printed board feed layer, a reflection bottom plate, a radio frequency coaxial connector and screws. According to the antenna unit, broadband wide-angle scanning can be realized through slot coupling and parasitic patch loading; according to the invention, current transmission is destroyed or resonance is caused by slotting and the like, and second and third harmonics are inhibited; by designing the shape of the patch, the link loss can be reduced, and the antenna efficiency is improved; the antenna array plane architecture of the traditional ground radar is that an antenna and an antenna housing are independently designed, and the antenna and the antenna housing are integrally designed, so that the link loss is reduced; the metal layer is plated inside the PPS medium, the PPS medium has characteristics, and the antenna material has a protection function and is good in environmental adaptability.

Description

Technical Field

[0001] The present invention mainly relates to the field of antenna and microwave technology, and in particular to a radome-integrated array antenna unit and system. Background Art

[0002] As a shell structure that protects the antenna from the natural environment, the radome is particularly important in large radar systems. Due to the large size and large number of units of large radars, traditional metal structure radomes are usually formed by machining and other methods, resulting in high costs and heavy weight. In order to reduce costs and achieve lightweight, thermoplastic materials and their processes are introduced into the integrated unit design of phased array radomes. Thermoplastic materials not only have a low density, but can also be manufactured in complex shapes through processes such as injection molding, thereby reducing weight and reducing production costs while ensuring structural strength.

[0003] Microstrip antennas are widely used in a variety of platforms due to their low profile and easy conformal integration, especially in microwave equipment that needs to be miniaturized and lightweight. In order to meet the higher requirements of modern microwave equipment for antenna performance, microstrip antennas not only need to have basic characteristics such as broadband, multi-band, miniaturization and multi-function, but also need to have low loss, lightweight and easy processing. These characteristics make microstrip antennas have broad application prospects in radar, communication and electronic warfare.

[0004] In electromagnetic information interaction, the harmonics of antenna integrated components are an important source of interference. Harmonic signals are usually suppressed by filters in the circuit. The most direct and effective method is to cascade the antenna and the filter and use the frequency selection characteristics of the filter to remove out-of-band signals. However, traditional design methods often lead to larger system size and increased losses, and may cause the antenna to malfunction due to impedance mismatch. Summary of the invention

[0005] The purpose of the present invention is to provide an array antenna unit and system with an integrated antenna cover. In view of the problems that traditional design methods will cause the system size to become larger, the loss to increase, and the antenna may not work normally due to impedance mismatch, the antenna unit of the present invention has the advantages of low loss, low profile, low cost, good consistency, good environmental adaptability, etc. The antenna array composed of the antenna unit has wide bandwidth angle scanning and second and third harmonic suppression characteristics, and is suitable for forming a large phased array antenna.

[0006] To achieve the above-mentioned object, the present invention provides a radome integrated array antenna unit, comprising a radiation layer, a printed circuit board feeding layer, and a reflective bottom plate; The radiation layer includes a main shell, a parasitic patch layer, an auxiliary shell, and a main patch layer. The parasitic patch layer is formed by electroplating inside the main shell, and the main patch layer is formed by electroplating inside the auxiliary shell. The auxiliary shell and the main shell are interconnected. The RF coaxial connector is welded to the feed layer of the printed circuit board; In order from top to bottom, the radiation layer, printed circuit board feeding layer and reflective base plate are fixed in sequence by metal screws.

[0007] Furthermore, the material used for the main shell and the auxiliary shell is polyphenylene sulfide PPS.

[0008] Furthermore, an air cavity is formed between the main shell, the auxiliary shell, and the printed circuit board feeding layer, and the radio frequency signal couples the energy to the parasitic patch layer and the main patch layer through the printed circuit board feeding layer, and finally radiates outwardly into the free space through the shell.

[0009] Furthermore, radiation patches are electroplated on the surfaces of both the main shell and the auxiliary shell to form a double resonant circuit, and an air cavity is formed between the main shell, the auxiliary shell and the printed circuit board feeding layer.

[0010] Furthermore, two gaps of different lengths are etched on the main patch layer of the auxiliary shell to destroy the current transmission in the secondary frequency band, suppress the antenna radiation, and achieve harmonic suppression.

[0011] Furthermore, the transmission characteristics in the third frequency band are destroyed and harmonics are suppressed by cutting corners on the main patch layer and the parasitic patch layer.

[0012] Furthermore, the aspect ratio of the main patch layer and the parasitic patch layer is adjusted, so as to adjust the frequency band range of the TE10 mode and suppress the second harmonic.

[0013] Furthermore, the size of the main shell is 0.29l0×0.31l0×0.1l0, the size of the auxiliary shell is 0.24l0×0.27l0×0.05l0, the size of the parasitic patch layer is 0.25l0×0.28l0, the size of the main patch layer is 0.20l0×0.23l0, the thickness of the main patch layer and the parasitic patch layer is 16μm, the gap on the left side of the patch layer is 0.1l0×0.01l0, and the total length of the gap on the right side is approximately 0.2l0.

[0014] In order to achieve the above-mentioned object, the present invention further provides a radome integrated array antenna system, comprising the radome integrated array antenna unit described in any one of the above-mentioned invention contents.

[0015] Furthermore, the antenna units of the integrated array of the radome are two-dimensionally replicated at a spacing of 0.46l0×0.5l0 to form a 64-point array.

[0016] Beneficial effects: The present invention provides an array antenna unit and system with integrated antenna cover, which have the following beneficial effects: (1) Wide bandwidth angular scanning: The antenna unit realizes wide bandwidth angular scanning by means of slot coupling and loading parasitic patches; (2) Harmonic suppression: According to the microstrip antenna fundamental, secondary and tertiary band in-band radiation characteristics, the secondary and tertiary harmonics are suppressed by destroying the current transmission or causing resonance by means of slits, etc.; (3) Low loss: Compared with the traditional method of loading filter branches to suppress harmonics, the present invention reduces the link loss and improves the antenna efficiency by designing the patch shape; the antenna array structure of the traditional ground radar is that the antenna and the antenna cover are designed independently, and the antenna and the antenna cover are now integrated to reduce the link loss; (4) Antenna cover integration: A metal layer is plated inside the PPS medium, and the PPS medium has characteristics. The antenna material has a protective function and good environmental adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a three-dimensional diagram of a radome-integrated array antenna with harmonic suppression characteristics according to an embodiment of the present invention; Figure 2 is a three-dimensional stereogram of a radome-integrated array antenna unit with harmonic suppression characteristics according to an embodiment of the present invention; Figure 3 is a side perspective view of a radome-integrated array antenna unit with harmonic suppression characteristics according to an embodiment of the present invention; Figure 4 It is a schematic diagram of assembling a radome-integrated array antenna unit with harmonic suppression characteristics according to an embodiment of the present invention; Figure 5 It is a schematic diagram of a main housing and a parasitic patch layer of a radome-integrated array antenna unit with harmonic suppression characteristics according to an embodiment of the present invention; Figure 6 It is a schematic diagram of an auxiliary shell and a main patch layer of a radome-integrated array antenna unit with harmonic suppression characteristics involved in an embodiment of the present invention; Figure 7 It is an E-plane scanning standing wave curve of the radome integrated array antenna with harmonic suppression characteristics involved in an embodiment of the present invention; Figure 8 It is an H-plane scanning standing wave curve diagram of the radome integrated array antenna with harmonic suppression characteristics involved in an embodiment of the present invention; Fig. 9 is a second and third harmonic suppression curve diagram of the radome integrated array antenna unit with harmonic suppression characteristics involved in an embodiment of the present invention; Fig.10 It is a unit pattern in an intermediate frequency array of a radome-integrated array antenna with harmonic suppression characteristics according to an embodiment of the present invention; Fig.11 It is an E-plane scanning pattern of an array antenna of a radome integrated array with harmonic suppression characteristics according to an embodiment of the present invention; Fig.12 It is an H-plane scanning pattern of an array antenna of a radome integrated array with harmonic suppression characteristics according to an embodiment of the present invention; Description of reference numerals: Among them: 1 is the PPS main shell; 2 is the parasitic patch layer; 3 is the PPS auxiliary shell; 4 is the main patch layer; 5 is the printed circuit board feeding layer; 6 is the reflective bottom plate; 7 is the RF connector; 8 is the screw. DETAILED DESCRIPTION

[0018] The preferred mechanism and implementation method of the present invention are further described below in conjunction with the accompanying drawings and specific implementation methods.

[0019] like Figures 1 to 12 As shown, an embodiment of the present invention discloses a radome-integrated array antenna unit and a system technical solution. Example 1

[0020] Figure 1-Figure 6 As shown, the antenna unit of the antenna cover integrated array with harmonic suppression characteristics of the present invention, wherein the antenna unit is composed of a PPS main shell 1, a parasitic patch layer 2, a PPS auxiliary shell 3, a main patch layer 4, a printed circuit board feeding layer 5, a reflective base plate 6, a RF coaxial connector 7, a screw 8, etc. from top to bottom.

[0021] The inside of the PPS main shell 1 is electroplated to form a parasitic patch layer 2, and the inside of the PPS auxiliary shell is electroplated to form a main patch layer 4. The PPS auxiliary shell and the PPS main shell are interconnected, and the RF coaxial connector 7 is welded to the printed circuit board feed layer 5. Then, from top to bottom, the radiation layer, the printed circuit board feed layer 5, and the reflective base plate 6 are fixed in sequence by metal screws 8, thereby realizing an antenna cover integrated array antenna with wide bandwidth angle scanning performance, harmonic suppression and high reliability.

[0022] Traditional antenna unit covers use very mature epoxy resin-based composite materials, and thermoplastic composite materials are rarely used. In the present invention, the shell is made of PPS (polyphenylene sulfide) material. In addition to high temperature resistance, corrosion resistance, wear resistance, flame retardancy, high rigidity, and low water absorption, PPS also has excellent electrical properties, dimensional stability, melt processability and other properties. Based on the excellent properties of this material, it is applied to the integrated array of antenna covers.

[0023] There is an air cavity between the PPS main shell 1, the PPS auxiliary shell 2, and the printed circuit board feed layer 5. The RF signal couples the energy to the parasitic patch layer 2 and the main patch layer 4 through the printed circuit board feed layer 5, and finally radiates outward to the free space through the shell. In order to achieve wide bandwidth angle scanning performance, the following measures are taken: (1) The air substrate is used between the printed circuit board feed layer and the patch to reduce the Q value of the equivalent circuit; (2) A double resonant circuit is formed by electroplating the radiation patch on the surface of the PPS main shell and the auxiliary shell, and the air cavity is formed between the main shell and the auxiliary shell and the printed circuit board feed layer to reduce the Q value, improve the antenna matching, and achieve wide bandwidth angle scanning performance. This type of structure has two guides, thus forming two resonant circuits with two resonant frequencies. When the two resonant frequencies are appropriately close, a double-peak resonant circuit with a greatly widened frequency band is formed; (3) The radiating patch is excited by the slot coupling feeding method, which can effectively expand the bandwidth.

[0024] The most direct and effective way to suppress harmonics is to cascade the antenna and filter, and use the frequency selection characteristics of the filter to remove out-of-band signals. The traditional design method of designing the two separately and then cascading them through transmission lines will cause the system to become larger, increase losses, and may also cause the antenna to not work properly due to impedance mismatch. The impedance mismatch method can effectively overcome a series of problems caused by cascade filters. A common measure of this method is to etch gaps on the radiating element so that the impedance at a specific frequency point is zero or infinite, resulting in impedance mismatch. According to the definition of the antenna reflection coefficient, when the input impedance at a frequency point is very low or very high, the absolute value of the reflection coefficient is close to 1, and almost no energy is radiated, so that the resonance at this frequency point is successfully suppressed. For example Figure 6 As shown in the figure, the patch antenna is used to suppress harmonics by selecting appropriate aspect ratios, cutting angles, digging grooves, etc. For example, two gaps of different lengths are etched on the main patch of the auxiliary shell to destroy the current transmission in the secondary frequency band, suppress antenna radiation, and achieve harmonic suppression; the main patch and the parasitic patch are cut to destroy the transmission characteristics in the third frequency band and suppress harmonics; the aspect ratio of the main patch and the parasitic patch is adjusted to adjust the frequency band range of the TE10 mode and suppress the second harmonic, as shown in the figure. Figure 5 and Figure 6 ; The antenna can achieve -20dB suppression in 80% bandwidth within the second and third harmonic range.

[0025] In order to meet the wide bandwidth angular scanning performance of the antenna, the electromagnetic field numerical algorithm is combined with simulation technology, and the purpose of improving the antenna radiation characteristics and S parameters is achieved through optimization design and performance comparison. In the design optimization stage, the unit spacing is a fixed parameter, and the length and width of the patch layer and the parasitic patch layer, the height of the air layer, the feed strip line of the printed circuit board feed layer, the coupling gap size, etc. are adjusted and optimized. Through the optimization of these parameters, the antenna performance requirements of wide bandwidth angular scanning and harmonic suppression are finally achieved. Example 2

[0026] This embodiment is basically the same as Embodiment 1, except that the embodiment of the present invention further discloses a radome integrated array antenna system. The main dimensions of the radome integrated array antenna unit with harmonic suppression characteristics are: PPS main shell 0.29l0×0.31l0×0.1l0, PPS auxiliary shell 0.24l0×0.27l0×0.05l0, parasitic patch layer 0.25l0×0.28l0, main patch layer 0.20l0×0.23l0, the thickness of the main patch layer and the parasitic patch layer is 16μm, the gap on the left side of the patch layer is 0.1l0×0.01l0, and the total length of the gap on the right side is about 0.2l0. The antenna unit is two-dimensionally replicated at a spacing of 0.46l0×0.5l0 to form a 64-point array.

[0027] The main performance indicators of the radome integrated array with harmonic suppression characteristics are: Working frequency: Fl~Fh; Standing wave ≤3.5; Scanning range: E surface ±45°, H surface ±60°; Second and third harmonic suppression: ≤-20dB within 80% bandwidth.

[0028] Figure 7 This is a standing wave curve diagram of the E-surface scanning of an embodiment of the present invention, Figure 8 This is a standing wave curve diagram of H-plane scanning of an embodiment of the present invention. In the figure, the horizontal axis represents the operating frequency, the vertical axis represents the standing wave (VSWR), and the four curves represent the change of standing wave with frequency when the antenna is not scanning (i.e., normal state), scanning 15°, 30°, 45°, and 60°. It can be seen that the working bandwidth with normal standing wave less than 3.5 is more than 24%; within the scanning range of 15°, 30°, and 45°, the active standing wave is less than 2.5; due to the surface wave effect, the high-frequency standing wave rises when the H-plane scans 60°, so this antenna unit has a wide bandwidth angle scanning capability.

[0029] Fig. 9 This is the normal second and third harmonic suppression curve of the antenna unit of an embodiment of the present invention under periodic boundary conditions. The horizontal axis of the graph is frequency, and the vertical axis is the transmission level of the antenna in the periodic boundary aperture of the antenna. It can be seen from the figure that the antenna transmission level is close to 0dB within the baseband range, and the antenna radiation efficiency is high at this time; the antenna transmission level of 80% bandwidth within the second and third harmonics (multiples of the baseband) range is less than -20dB, which means that the antenna effectively reduces the radiation level of the antenna in the harmonic range, so the antenna unit has harmonic suppression capability.

[0030] Fig.10 is the unit directional diagram in the center frequency array in the embodiment of the present invention, Fig.11 and Fig.12 This is the scanning pattern of the center frequency in the embodiment of the present invention. The antenna gain decreases by less than 2.5dB within the 45° range of two-dimensional scanning, and the gain decreases by less than 4dB at 60° in H-plane scanning compared to 0°, meeting the low loss requirement of the array surface.

[0031] The present invention aims to solve the problems that traditional design methods may cause the system size to become larger, the loss to increase, and the antenna may not work properly due to impedance mismatch. The antenna unit of the present invention has the advantages of low loss, low profile, low cost, good consistency, good environmental adaptability, etc. The antenna array composed of the antenna unit has wide bandwidth angle scanning and second and third harmonic suppression characteristics, and is suitable for forming a large phased array antenna.

[0032] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A radome integrated array antenna unit, characterized in that: Including radiation layer, printed circuit board feeding layer, and reflective bottom plate; The radiation layer includes a main shell, a parasitic patch layer, an auxiliary shell, and a main patch layer. The parasitic patch layer is formed by electroplating inside the main shell, and the main patch layer is formed by electroplating inside the auxiliary shell. The auxiliary shell and the main shell are interconnected. The RF coaxial connector is welded to the feed layer of the printed circuit board; In order from top to bottom, the radiation layer, printed circuit board feeding layer and reflective base plate are fixed in sequence by metal screws.

2. The radome integrated array antenna unit according to claim 1, characterized in that: The material used for the main shell and the auxiliary shell is polyphenylene sulfide PPS.

3. The radome integrated array antenna unit according to claim 1 or 2, characterized in that: There is an air cavity between the main shell, the auxiliary shell and the printed circuit board feeding layer. The radio frequency signal couples the energy to the parasitic patch layer and the main patch layer through the printed circuit board feeding layer, and finally radiates outward through the shell to the free space.

4. The radome integrated array antenna unit according to claim 1 or 2, characterized in that: Radiation patches are electroplated on the surfaces of the main shell and the auxiliary shell to form a double resonant circuit, and an air cavity is formed between the main shell, the auxiliary shell and the printed circuit board feeding layer.

5. The radome integrated array antenna unit according to claim 1, characterized in that: Two gaps of different lengths are etched on the main patch layer of the auxiliary shell to destroy the current transmission in the secondary frequency band, suppress antenna radiation, and achieve harmonic suppression.

6. The radome integrated array antenna unit according to claim 1, characterized in that: The transmission characteristics in the third frequency band are destroyed and harmonics are suppressed by cutting corners on the main patch layer and the parasitic patch layer.

7. The radome integrated array antenna unit according to claim 1, characterized in that: The frequency band of the TE10 mode is adjusted and the second harmonic is suppressed by adjusting the length-to-width ratio of the main patch layer and the parasitic patch layer.

8. The radome integrated array antenna unit according to claim 1, characterized in that: The dimensions of the main shell are 0.29l0×0.31l0×0.1l0, the dimensions of the auxiliary shell are 0.24l0×0.27l0×0.05l0, the dimensions of the parasitic patch layer are 0.25l0×0.28l0, the dimensions of the main patch layer are 0.20l0×0.23l0, the thickness of the main patch layer and the parasitic patch layer is 16μm, the gap on the left side of the patch layer is 0.1l0×0.01l0, and the total length of the gap on the right side is approximately 0.2l0.

9. A radome integrated array antenna system, characterized in that: It comprises the antenna cover integrated array antenna unit as described in any one of claims 1 to 8 above.

10. The radome integrated array antenna system according to claim 9, characterized in that: The antenna units of the integrated array of the radome are replicated in two dimensions at a spacing of 0.46l0×0.5l0 to form a 64-point array.

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