A large plane wave generator based on a periodic rectangular reflector antenna array

Abstract

The present invention provides a large plane wave generator based on a periodic rectangular reflector antenna array, which includes a periodic rectangular reflector antenna array, a mounting bracket for the rectangular reflector antenna array, an N-way equal power distribution network, N amplitude and phase stabilization cables, and a microwave signal source; the periodic rectangular reflector antenna array is vertically installed on the mounting bracket for the rectangular reflector antenna array and is connected to the N amplitude and phase stabilization cables, the N amplitude and phase stabilization cables are connected to the N-way equal power distribution network, and the N-way equal power distribution network is connected to the microwave signal source. The present invention realizes the equality of the electric field intensity and phase on the radiation aperture by optimizing the amplitude and phase distribution of its feed array antenna, so as to form a quasi-plane wave on the radiation aperture of the rectangular reflector antenna element. Then, N rectangular reflector antenna elements are arranged periodically, so as to form a large plane wave on the radiation aperture of the periodic rectangular reflector antenna array.

Description

Technical Field

[0001] The present invention relates to the technical field of microwave and wireless communication measurement, and particularly relates to a large plane wave generator based on a periodic rectangular reflector antenna array. Background Art

[0002] When testing the performance of electrically large antennas, the electromagnetic scattering characteristics (RCS) of electrically large targets, and the over-the-air (OTA) performance of electrically large wireless communication devices, in order to simulate the illumination of incoming waves from the far field, it is necessary to form a large plane wave test electric field. Currently, the methods for forming a plane wave test electric field mainly include the antenna far-field method, the compact range method, and the array antenna plane wave conversion method. The antenna far-field method is affected by distance and cannot be realized in a microwave anechoic chamber with limited space. When implementing a large plane wave using the compact range method, a metal reflector with a large aperture is required, and due to the deformation effect of the mechanical structure, the quality of the plane wave cannot be guaranteed. When designing a large plane wave using the array antenna plane wave conversion method, it is also affected by low aperture efficiency, a huge number of array elements and transceiver channels, and thus cannot be realized in engineering. Summary of the Invention

[0003] Object of the Invention: The technical problem to be solved by the present invention is to provide a large plane wave generator based on a periodic rectangular reflector antenna array in view of the deficiencies of the prior art, and use the formed large plane wave test electric field to test the radar cross section, antenna performance, or over-the-air performance of an electrically large scattering target, an electrically large antenna, or an electrically large wireless communication product.

[0004] The present invention specifically includes a periodic rectangular reflector antenna array, a rectangular reflector antenna array mounting bracket, an N-way equal power distribution network, N amplitude and phase stabilized cables, and a microwave signal source;

[0005] The periodic rectangular reflector antenna array is vertically installed on the rectangular reflector antenna array mounting bracket and is connected to N amplitude and phase stabilized cables. The N amplitude and phase stabilized cables are connected to the N-way equal power distribution network, and the N-way equal power distribution network is connected to the microwave signal source.

[0006] The periodic rectangular reflector antenna array is composed of N rectangular reflector antenna units arranged periodically;

[0007] The rectangular reflector antenna unit includes a rectangular metal reflector, a feed array antenna, and a feed array antenna bracket;

[0008] The feed array antenna is composed of M feed array antenna units arranged in a rectangular form;

[0009] The feed array antenna is installed on the top of the rectangular metal reflector through the feed array antenna bracket, and the radiation direction is aligned with the normal direction of the center of the rectangular metal reflector;

[0010] The feed array antenna is connected to the amplitude and phase stabilization cable.

[0011] Under the set periodic boundary conditions, a rectangular reflector antenna element is designed. Electric field observation points are set on the radiation aperture surface of the rectangular reflector antenna element. The excitation distribution of the feed array antenna is calculated using a constrained optimization algorithm so that the electric field intensity and phase angle at the observation points are equal.

[0012] The constrained optimization algorithm is the maximum power transfer method under constraints, and the formula is:

[0013]

[0014] where Max represents finding the maximum value of the main function. The physical meaning of the main function is the total electric field power density at the observation points. S.T. represents the constraint conditions, C is a constant, M is the number of set electric field observation points, and E(r p ) is the electric field values at p observation points set on the radiation aperture surface of the rectangular reflector antenna element, and ε 0 represents the air dielectric constant. Finding the extreme value of the main function and constraining the power density of each electric field observation point to be equal indicates that the energy radiated by the rectangular reflector antenna element is maximized and evenly distributed on its radiation aperture surface, thus forming a plane wave.

[0015] The rectangular metal reflector is generated by rotating a parabola around the normal of the reflector center to form a circular reflector and then performing rectangular cutting.

[0016] The feed array antenna is composed of 4×4 feed array antenna elements arranged in a semi-wavelength period in the horizontal direction (X-axis) and the vertical direction (Y-axis).

[0017] The excitation distribution of the feed array antenna is realized by a fixed feed network or an adjustable transceiver component. The fixed feed network divides the feeder signals from the rectangular reflector antenna element into 16 paths according to the amplitude and phase distribution and transmits them to 16 feed array antenna elements respectively. The adjustable transceiver component equally divides the feed signals into 16 paths and transmits them to 16 feed arrays through the phase shifters, attenuators, and amplifiers on 16 branches (the branches are structures on the fixed feed network that divide one excitation signal into 16 paths according to the excitation distribution conditions to respectively excite 16 feed array antenna elements). The amplitude and phase output of the fixed feed network meet the excitation distribution requirements of the optimized design feed array antenna.

[0018] The microwave signal source generates microwave signals of a specific frequency. The microwave signals are transmitted through an N-way equal-power distribution network and N amplitude-stabilized and phase-stabilized cables to N rectangular reflector antenna elements for simultaneous feeding, and finally a large plane wave is formed on the radiation aperture surface of the periodic rectangular reflector antenna array.

[0019] The size of the rectangular metal reflector is much larger than that of the feed array antenna to reduce the blocking effect of the feed array antenna on the reflected wave, such as a ratio of more than 10 times.

[0020] When the periodic rectangular reflector antenna array is designed to operate at 2 GHz, the size of a single feed array antenna is 0.3 m × 0.3 m, and the size of a single rectangular metal reflector is 3.5 m × 3.5 m.

[0021] The distance from the feed array antenna to the rectangular metal reflector is much larger than the antenna wavelength, such as a ratio of more than 10 times. When the operating frequency of the feed array antenna is 2 GHz, the typical distance from the feed array antenna to the rectangular metal reflector is 2.5 m.

[0022] N is greater than or equal to 9, so that at least one rectangular reflector antenna element satisfies the quasi-periodic boundary condition (the meaning of "quasi" is "close". 9 elements can be arranged in a 3*3 pattern in the X-axis and Y-axis directions, and the repetition number on each axis is only 3, without forming a standard period (generally, the number of elements recognized as a standard period is 5 or more), so it is called "quasi-period"), thus forming a quasi-large plane wave on the aperture of the reflector antenna array.

[0023] When the feeding network is a fixed feeding network, it includes a microstrip power divider and a phase shifter.

[0024] Using more than 9 rectangular reflector antenna elements for periodic arrangement, the aperture size of the formed large plane wave can reach the order of 10 m.

[0025] The beneficial effects of the present invention are as follows: The present invention proposes a large plane wave generator based on a periodic rectangular reflector antenna array. The periodic rectangular reflector antenna array is composed of N rectangular reflector antenna elements arranged periodically. Each rectangular reflector antenna element is designed under periodic boundary conditions. By optimizing the amplitude and phase distribution of its feed array antenna, the electric field intensity and phase on the radiation aperture are made equal, so as to form a quasi-plane wave on the radiation aperture of the rectangular reflector antenna element. Then, the N rectangular reflector antenna elements are arranged periodically, thus forming a large plane wave on the radiation aperture of the periodic rectangular reflector antenna array. Description of the Drawings

[0026] Figure 1 It is a schematic diagram of a large plane wave generator based on a periodic rectangular reflector antenna array according to an embodiment of the present invention.

[0027] Figure 2 is the rectangular reflector antenna element under periodic boundary conditions of the embodiment of the present invention.

[0028] Figure 3 is the schematic diagram of the feed array antenna structure of the rectangular reflector antenna element of the embodiment of the present invention.

[0029] Figure 4 is the optimization result of the electric field distribution on the radiation aperture surface of the rectangular reflector antenna element of the embodiment of the present invention.

[0030] Figure 5 is the optimization result of the electric field distribution on the radiation aperture surface of the periodic rectangular reflector antenna array according to the embodiment of the present invention (3D perspective).

[0031] Figure 6 is the optimization result of the electric field distribution on the radiation aperture surface of the periodic rectangular reflector antenna array according to the embodiment of the present invention (top view).

[0032] Figure 7 is the electric field amplitude ripple on the central X-axis of the radiation aperture surface of the periodic rectangular reflector antenna array of the embodiment of the present invention.

[0033] Figure 8 is the electric field phase ripple on the central X-axis of the radiation aperture surface of the periodic rectangular reflector antenna array of the embodiment of the present invention.

[0034] Figure 9 is the electric field amplitude ripple on the central Y-axis of the radiation aperture surface of the periodic rectangular reflector antenna array of the embodiment of the present invention.

[0035] Figure 10 is the electric field phase ripple on the central Y-axis of the radiation aperture surface of the periodic rectangular reflector antenna array of the embodiment of the present invention.

[0036] Figure 11 is the schematic diagram of a single rectangular reflector antenna element.

[0037] Description of reference numerals:

[0038] 1. Radiation aperture surface of the periodic rectangular reflector antenna array; 2. Periodic rectangular reflector antenna array; 3. Mounting bracket of the rectangular reflector antenna array; 4. N amplitude-stabilized and phase-stabilized cables; 5. N-way equal-power distribution network; 6. Microwave signal source; 7. Feed array antenna; 8. Mounting bracket of the feed array antenna; 9. Rectangular metal reflector; 10. Radiation aperture surface of the rectangular reflector antenna element; 11. Periodic boundary of the rectangular reflector antenna element; 12. Mounting hole of the mounting bracket of the feed array antenna; 13. Coaxial feed port; 14. Feed array antenna element; 15. Fixed feed network. Detailed Embodiment

[0039] The following further specifically describes the present invention in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become clearer.

[0040] An embodiment of the present invention provides a large plane wave generator based on a periodic rectangular reflector antenna array, including a periodic rectangular reflector antenna array 2, a rectangular reflector antenna array mounting bracket 3, an N-way equal power distribution network 5, N amplitude and phase stabilized cables 4, and a microwave signal source 6;

[0041] The periodic rectangular reflector antenna array 2 is vertically mounted on the rectangular reflector antenna array mounting bracket 3 and is connected to N amplitude and phase stabilized cables 4. The N amplitude and phase stabilized cables 4 are connected to an N-way equal power distribution network 5, and the N-way equal power distribution network 5 is connected to the microwave signal source 6;

[0042] The periodic rectangular reflector antenna array 2 is composed of N rectangular reflector antenna elements arranged periodically;

[0043] The number of rectangular reflector antenna elements of the periodic rectangular reflector antenna array 2 can be set to 9, and after being arranged periodically in the X and Y axis directions, as Figure 1 shown.

[0044] In this embodiment, the rectangular reflector antenna element is composed of a feed array antenna 7, a feed array antenna bracket 8, and a rectangular metal reflector 9, as Figure 2 , Figure 11 shown. The rectangular reflector antenna element is designed under the periodic boundary 11 conditions of the set rectangular reflector antenna element. By optimizing the amplitude and phase distribution of the feed array antenna, a quasi-plane wave is formed on the radiation aperture surface 10 of the rectangular reflector antenna element. Specifically, a number of electric field observation points are set on the radiation aperture surface 10 of the rectangular reflector antenna element, and the excitation distribution of the feed array antenna is calculated using a constrained optimization algorithm so that the electric field intensity and phase angle at the observation points are equal. A fixed feeding network distributes the feeding signal power from the amplitude and phase stabilized cable into 16 paths and transmits it to 16 feed array antenna elements 14. The amplitude and phase output of the fixed feeding network satisfy the excitation distribution of the optimized feed array antenna.

[0045] In this embodiment, 9 rectangular reflector antenna elements are arranged periodically to form a periodic rectangular reflector antenna array 2, as Figure 1 shown. The microwave signal source 6 continuously generates a signal with a specific frequency of 2 GHz. This signal is stably transmitted through the N-way equal power distribution network 5 and the amplitude and phase stabilized cables to each periodic rectangular reflector antenna array 2 for feeding, and finally a large plane wave is formed on the radiation aperture surface 1 of the periodic rectangular reflector antenna array.

[0046] In this embodiment, the feed array antenna of the rectangular reflector antenna unit is as Figure 3 shown, and it is composed of an antenna array consisting of 4×4 feed array antenna units 14, a fixed feeding network 15, a coaxial feeding port 13, and a mounting hole 12 for the feed array antenna support. The mounting hole 12 for the feed array antenna support is connected to the feed array antenna support 8 and fixed on the rectangular metal reflector 9. In addition, the optimal excitation distribution signal obtained through the optimization algorithm enters the feed array antenna through the coaxial feeding port 13, and then the signal is transmitted to each feed array antenna unit 14 through the fixed feeding network 15.

[0047] In this embodiment, a rectangular reflector antenna unit operating at 2 GHz is designed, as Figure 2 shown. The size of the rectangular metal reflector 9 is 3.5 m × 3.5 m, the size of the feed array antenna 7 is 0.3 m × 0.3 m, and the distance from the feed array antenna 7 to the rectangular metal reflector 9 is 2.5 m. The structure is modeled using commercial electromagnetic simulation software. After setting the periodic boundary conditions in the X and Y axis directions, electromagnetic simulation is carried out. At the same time, several observation points are set on the radiation aperture surface 10 of the rectangular reflector antenna unit. The amplitude and phase distribution of the feed array antenna are optimized using the constrained optimization algorithm, so that the electric field amplitude and phase at the observation points are evenly distributed, and thus the optimal excitation distribution of the feed array antenna is obtained. A fixed feeding network 15 is designed based on the optimal excitation distribution of this feed array antenna, and the electric field distribution on the radiation aperture surface of the rectangular reflector unit under the periodic boundary 11 conditions of the rectangular reflector antenna unit is obtained.

[0048] Furthermore, 3×3 rectangular reflector antenna units are periodically arranged to form a rectangular reflector antenna array, as Figure 1 shown. The size of the rectangular reflector antenna array is 10.5 m × 10.5 m. The microwave signals generated by the microwave signal source 6 are respectively transmitted to 9 rectangular reflector antenna units through a 9-way equal power divider and 9 amplitude and phase stabilized cables, and thus the electric field distribution on the radiation aperture surface 1 of the 3×3 periodic rectangular reflector antenna array is obtained.

[0049] Figure 6 is the vector diagram of the electric field distribution on the radiation aperture surface of the periodic rectangular metal reflector antenna array. The observed size of the radiation aperture surface is 10.5 m × 10.5 m, the size of the formed large plane wave is 10 m × 10 m, and the aperture efficiency of the generated plane wave is 91%.

[0050] Figure 7 is the electric field amplitude ripple on the X axis at the center of the radiation aperture surface of the periodic rectangular metal reflector antenna array. The amplitude ripple in the 10 m observation area is less than 1 dB.

[0051] Figure 8 is the electric field phase ripple of the periodic rectangular metal reflector antenna array on the X-axis at the center of the radiation aperture plane, and the amplitude ripple in the 10m observation area is less than 3 degrees.

[0052] Figure 9 is the electric field amplitude ripple of the periodic rectangular metal reflector antenna array on the Y-axis at the center of the radiation aperture plane, and the amplitude ripple in the 10m observation area is less than 1dB.

[0053] Figure 10 is the electric field phase ripple of the periodic rectangular metal reflector antenna array on the Y-axis at the center of the radiation aperture plane, and the amplitude ripple in the 10m observation area is less than 3 degrees.

[0054] In summary, the 3×3 periodic rectangular reflector antenna array realizes a large-size plane wave on the order of 10m.

[0055] The present invention provides a large plane wave generator based on a periodic rectangular reflector antenna array. There are many methods and ways to specifically implement this technical solution. The above description is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be implemented by existing technologies.

Claims

1. A large plane wave generator based on a periodic rectangular reflector antenna array, characterized in that: It includes a periodic rectangular reflector antenna array, a rectangular reflector antenna array mounting bracket, an N-way equal power distribution network, N amplitude-stabilized and phase-stabilized cables and a microwave signal source; The periodic rectangular reflector antenna array is vertically mounted on a rectangular reflector antenna array mounting bracket and connected to N amplitude-stabilizing and phase-stabilizing cables, the N amplitude-stabilizing and phase-stabilizing cables are connected to an N-way equal power distribution network, and the N-way equal power distribution network is connected to a microwave signal source; The periodic rectangular reflector antenna array is composed of N rectangular reflector antenna units arranged periodically; The rectangular reflector antenna unit comprises a rectangular metal reflector, a feed array antenna and a feed array antenna bracket; The feed array antenna is composed of M feed array antenna units arranged in a rectangular shape; The feed array antenna is installed on the top of the rectangular metal reflective surface through the feed array antenna bracket, and the radiation direction is aligned with the center normal of the rectangular metal reflective surface; The feed array antenna is connected to an amplitude- and phase-stabilizing cable; Under the set periodic boundary conditions, a rectangular reflector antenna unit is designed, an electric field observation point is set on the radiation aperture surface of the rectangular reflector antenna unit, and a constrained optimization algorithm is used to calculate the excitation distribution of the feed array antenna so that the electric field intensity and phase angle at the observation point are equal; The constrained optimization algorithm is a maximum power transmission method under constraints, and the formula is: Among them, Max means to find the maximum value, ST means the constraint condition, C is a constant, M is the number of electric field observation points set, E(r p ) is the electric field value of p observation points set on the radiation aperture surface of the rectangular reflector antenna unit, and ε0 represents the dielectric constant of air.

2. A large plane wave generator based on a periodic rectangular reflector antenna array as claimed in claim 1, characterized in that: The rectangular metal reflective surface is generated by rotating a parabola based on the normal direction of the center of the reflective surface to generate a circular reflective surface, and then performing rectangular cutting to generate the circular reflective surface.

3. A large plane wave generator based on a periodic rectangular reflector antenna array as claimed in claim 2, characterized in that: The feed array antenna is composed of 4×4 feed array antenna units arranged in a half-wavelength period in the horizontal direction and the vertical direction.

4. A large plane wave generator based on a periodic rectangular reflector antenna array as claimed in claim 3, characterized in that: The excitation distribution of the feed array antenna is realized by a fixed feeding network or an adjustable transceiver component; the fixed feeding network divides the feed line signal from the rectangular reflector antenna unit into 16 paths according to amplitude and phase distribution, and transmits them to the 16 feed array antenna units respectively; the adjustable transceiver component divides the feed signal into 16 paths, and transmits them to the 16 feed array antenna units respectively through phase shifters, attenuators and amplifiers on the 16 branches; the amplitude and phase outputs of the fixed feeding network meet the excitation distribution requirements of the optimized designed feed array antenna.

5. A large plane wave generator based on a periodic rectangular reflector antenna array as claimed in claim 4, characterized in that: The microwave signal source generates a microwave signal, which is transmitted to N rectangular reflector antenna units through N equal power distribution networks and N amplitude and phase stabilized cables for simultaneous feeding, and finally forms a large plane wave on the radiation aperture surface of the periodic rectangular reflector antenna array.

6. A large plane wave generator based on a periodic rectangular reflector antenna array as claimed in claim 5, characterized in that: The size of the rectangular metal reflective surface is larger than the feed array antenna.

7. A large plane wave generator based on a periodic rectangular reflector antenna array as claimed in claim 6, characterized in that: The distance between the feed array antenna and the rectangular metal reflective surface is greater than the antenna wavelength; The value of N is greater than or equal to 9, so that at least one rectangular reflector antenna unit satisfies the quasi-periodic boundary condition, thereby forming a quasi-large plane wave on the aperture of the reflector antenna array.

8. A large plane wave generator based on a periodic rectangular reflector antenna array as claimed in claim 7, characterized in that: When the feeding network is a fixed feeding network, it includes a microstrip power divider and a phase shifter.

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