A strong radiation field simulation system of variable polarization array antenna based on phase-shift control

Abstract

The application discloses a variable polarization array antenna strong radiation field simulation system based on phase shift control, belongs to the technical field of antenna and radio frequency microwave radiation field environment simulation, and aims at the technical requirement that a large irradiation range, high radiation field intensity and horizontal polarization and vertical polarization state switching need to be simulated in a high-intensity radio frequency radiation sensitivity test. The variable polarization array antenna strong radiation field simulation system based on phase shift control is provided, a high-intensity radio frequency radiation field meeting the requirement can be simulated by using a high-power radio frequency power amplifier array and a transmitting antenna array structure system, horizontal polarization and vertical polarization conversion is convenient and fast, and the reliability is high, so that radiation sensitivity test research and evaluation and assessment of electronic equipment can be conveniently carried out in a laboratory.

Description

Technical Field

[0001] This invention belongs to the field of antenna and radio frequency microwave radiation field environment simulation technology, and more specifically, relates to a strong radiation field environment simulation system based on phase shift control of variable polarization array antenna. Background Technology

[0002] When conducting radiation susceptibility tests on electronic equipment (frequency range required: 10kHz–45GHz, or according to actual environmental requirements), a transmission system typically consists of a signal source, an RF power amplifier, and a transmitting antenna. This system generates the required RF radiation electromagnetic environment in the test space. During the test, both horizontal and vertical polarization irradiation tests are usually required (below 30MHz, the transmitting antenna is typically larger, and the radiation field is more affected by the surrounding boundary environment; horizontal and vertical polarization irradiation is not required). Typically, the transmitting antenna is connected to the RF power amplifier via RF cable or flexible waveguide, and the transmitting antenna is a small single antenna. Due to limitations in the power output of a single RF power amplifier and the power capacity and irradiation range of a single transmitting antenna, the radiation field strength is generally in the tens to hundreds of V / m range. Antenna sizes are also relatively small in most frequency bands. The horizontal and vertical polarization of the transmitting antenna can be switched by rotating it 90 degrees.

[0003] However, for external high-intensity radiation field tests with peak field strengths reaching tens of kV / m, the power requirements of broadband RF power amplifiers reach the hundreds of kilowatts. A single power amplifier and a single transmitting antenna element cannot meet the test requirements, necessitating the use of array radiation. To reduce microwave RF transmission loss, the power amplifier element and the antenna element are connected using the shortest possible rigid transmission line. To change the polarization of the radiation field, the following methods can be considered: (1) Add a rotating joint and driving device to each antenna element (or set a limit switch for manual rotation to achieve switching between horizontal and vertical polarization). By rotating each antenna element, all antenna elements are uniformly in a horizontal or vertical polarization state, so that the entire antenna array radiates in a horizontal or vertical polarization field; (2) Arrange two sets of antenna arrays, one set of antenna elements is all horizontally polarized, and the other set of antenna elements is all vertically polarized. The two sets of antenna arrays are connected to the RF power amplifier array by a polarization switching switch. Through the mechanical action of the RF polarization switching switch, the horizontal and vertical polarization of the two sets of radiating antenna arrays are switched to achieve the conversion between horizontal and vertical polarization radiation fields; (3) Rotate the RF power amplifier array and the transmitting antenna array together by 90 degrees to achieve the conversion between horizontal and vertical polarization radiation fields. All three of the above schemes have certain problems. Scheme (1) is too complicated to use and requires a lot of work. It is difficult to implement when the number of antenna elements reaches hundreds or even thousands, or when the antenna elements are arranged compactly with small gaps. Scheme (2) is relatively simple and feasible, but the high-power RF polarization switching array with frequent operation requires high reliability. Otherwise, if the switching switch does not operate properly, it will lead to RF channel mismatch or even short circuit, causing an increase in reflection coefficient. At best, it will reduce the radiation field strength, and at worst, it will cause the RF power amplifier to burn out, resulting in serious losses. Scheme (3) is suitable for cabinets with small size and weight, but the size of the RF power amplifier array cabinet with power reaching tens or even hundreds of kilowatts will reach about 3 meters and the weight will reach several tons. There are also power supply, control, cooling and other protection subsystems connected on the cabinet, making it very difficult to rotate the whole 90 degrees to change the polarization. The system size is larger and it is not suitable for laboratory use. Summary of the Invention

[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention proposes a high-intensity radiation field simulation system based on phase-shift control for a variable polarization array antenna. It primarily solves the problems of generating wide-bandwidth, large-area, high-intensity radio frequency radiation fields in high-intensity radio frequency radiation susceptibility tests, as well as the convenient switching between horizontal and vertical polarization modes during the test. It is applicable to fields such as simulating electromagnetic environments of high-intensity radio frequency radiation fields and testing the radio frequency radiation susceptibility of electronic equipment.

[0005] To achieve the above objectives, the present invention provides a strong radiation field simulation system for a variable polarization array antenna based on phase shift control, comprising: a pre-amplifier, a power divider, an amplitude and phase controller, and a planar array antenna;

[0006] The planar array antenna includes several radiating elements, each of which consists of two orthogonally arranged antenna elements. Each antenna element includes a digitally controlled phase shifter, a digitally controlled attenuator, a final-stage power amplifier, an isolator, and a transmitting antenna connected in sequence.

[0007] The input radio frequency signal is amplified by the pre-amplifier and then distributed by the power divider, expanding the number of radio frequency signal channels to the number of antenna elements. The amplitude of each signal channel meets the drive level of the final stage power amplifier and enables the final stage power amplifier to generate sufficient output power.

[0008] Each radio frequency signal output by the power divider is fed to the corresponding transmitting antenna after passing through a digitally controlled phase shifter, a digitally controlled attenuator, a final stage power amplifier, and an isolator. Each transmitting antenna radiates into the air and synthesizes to generate a high-intensity radio frequency radiation field that meets the requirements in the designated area.

[0009] For vertically polarized radiation field tests or horizontally polarized radiation field tests, the phase and amplitude of the RF signal fed to the antenna unit are adjusted by controlling the amplitude and phase controller and adjusting the digitally controlled phase shifter and digitally controlled attenuator of each RF signal channel output by the power divider.

[0010] In some alternative implementations, the polarization directions of the two orthogonally arranged antenna elements in the radiating element are symmetrically arranged at a 45-degree angle to the vertical direction.

[0011] In some alternative implementations, the two orthogonally arranged antenna elements in the radiating element are fabricated as a single unit, and the two antenna elements are fed by two coaxial ports at the bottom.

[0012] In some alternative implementations, the two orthogonally arranged antenna elements in the radiating element are Vivaldi antennas or double-ridged horn antennas with a working bandwidth of not less than one octave and good linear polarization characteristics.

[0013] In some alternative implementations, the final stage power amplifier uses the same model of RF power amplifier module with substantially the same amplitude and phase characteristics; the isolator uses the same model of isolator with substantially the same amplitude and phase characteristics.

[0014] In some alternative implementations, when conducting vertically polarized radiation field tests, the phase shifter and attenuator of each RF signal channel output by the power divider are adjusted by controlling the amplitude and phase controller, so that the RF signals fed to the two orthogonally arranged antenna elements in the radiating element have the same phase and amplitude.

[0015] In some alternative implementations, when conducting horizontally polarized radiation field tests, the phase shifters and attenuators of each RF signal channel output by the power divider are adjusted by controlling the amplitude and phase controller, so that the RF signals fed to the two orthogonally arranged antenna elements in the radiating element have opposite phases and the same amplitude.

[0016] In some alternative implementations, the radiation pattern of the planar array antenna is adjusted by adjusting the phase difference of each radiating element, so that the illumination beam can scan within a certain range in the elevation and horizontal directions.

[0017] In summary, compared with the prior art, the technical solutions conceived in this invention solve the problem of laboratory simulation of wide-bandwidth, high-intensity radio frequency radiation, and can achieve the following beneficial effects:

[0018] By employing spatial synthesis, the problem of insufficient power of individual power amplifier modules and individual radiating antenna elements to generate the required high-intensity radio frequency radiation field in the test area is effectively solved. The phase-shift control method is used to conveniently solve the problem of switching between the horizontal and vertical polarization radiation fields of the array antenna. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a planar array antenna arrangement provided in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of a radiating element (dual-polarized Vivaldi antenna) structure provided in an embodiment of the present invention, wherein (a) is a schematic diagram of the side structure and (b) is a schematic diagram of the bottom feed point;

[0021] Figure 3 This is a system overall composition principle block diagram provided by an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of a polarization synthesis principle provided in an embodiment of the present invention, wherein (a) represents vertical polarization and (b) represents horizontal polarization;

[0023] Figure 5 This is a schematic diagram of an antenna array distribution provided in an embodiment of the present invention;

[0024] Figure 6 This is a simulation diagram of a 4GHz field strength distribution provided by an embodiment of the present invention;

[0025] Figure 7 This is a simulation diagram of a 5GHz field strength distribution provided by an embodiment of the present invention;

[0026] Figure 8 This is a simulation diagram of a 6GHz field strength distribution provided by an embodiment of the present invention;

[0027] Figure 9 This is a simulation diagram of a 7GHz field strength distribution provided by an embodiment of the present invention;

[0028] Figure 10 This is a simulation diagram of an 8GHz field strength distribution provided by an embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0030] This invention addresses the technical requirement in high-intensity radio frequency radiation susceptibility testing to simulate a large irradiation range, high radiation field strength, and the need for switching between horizontal and vertical polarization states. It proposes a high-intensity radiation field simulation system based on a variable polarization array antenna with phase-shift control. The radiation system employs a high-power radio frequency power amplifier array and a transmitting antenna array structure, capable of simulating a high-intensity radio frequency radiation field that meets the requirements. Furthermore, the switching between horizontal and vertical polarization is convenient, fast, and highly reliable, facilitating radiation susceptibility testing and evaluation of electronic equipment in the laboratory.

[0031] This invention proposes a strong radiation field simulation system for a variable polarization array antenna based on phase-shift control, comprising:

[0032] (1) Using a planar array antenna for radiation, and utilizing the principle of spatial synthesis, a high field strength required for the experiment is generated within a certain range of the test area. The radiating element T of the planar array antenna... ij The quantity is m×n (e.g. Figure 1 (as shown), i = 1, 2, ..., m, j = 1, 2, ..., n;

[0033] (2) Each group of radiating elements T of the array antenna ij Two orthogonally arranged antenna elements a ij and b ij Composition, two antenna elements a ij and b ijThe polarization directions are symmetrically arranged at a 45-degree angle to the vertical direction (e.g. Figure 1 (The antenna radiating element arrangement shown in the figure);

[0034] (3) A tightly coupled arrangement is adopted, and the radiating element T ij Two orthogonally arranged antenna elements a ij and b ij Integrated processing (such as) Figure 2 As shown, (a) is a schematic diagram of the side structure, and (b) is a schematic diagram of the bottom feed point. The two antenna elements a are fed by two coaxial ports at the bottom. ij and b ij Power supply;

[0035] (4) Antenna element a ij and b ij Use a Vivaldi antenna or a double-ridged horn antenna with a working bandwidth of not less than one octave and good linear polarization characteristics, and make an appropriate selection based on the working frequency band and its manufacturing difficulty;

[0036] (5) The input RF signal is amplified by the pre-amplifier and then distributed by the power divider. A step-by-step amplification and distribution method can be used to expand the number of RF signal paths to the number of antenna elements m×n×2, with each signal Sa... ij Sb ij The amplitude of the amplifier meets the drive level of the final stage power amplifier and enables the final stage power amplifier to generate sufficient output power. All final stage power amplifiers use the same model of RF power amplifier module with basically the same amplitude and phase characteristics. Similarly, all isolators are also the same model with basically the same amplitude and phase characteristics.

[0037] (6) Each RF signal Sa output by the power divider ij Sb ij After passing through a digitally controlled phase shifter, a digitally controlled attenuator, a final-stage power amplifier, and an isolator, the signal is fed to the corresponding transmitting antenna. Each transmitting antenna radiates into the air, synthesizing a high-intensity radio frequency radiation field that meets the requirements in a designated area, such as... Figure 3 As shown;

[0038] (7) When conducting vertically polarized radiation field tests, the amplitude and phase controller is controlled by the system software to adjust Sa. ij Sb ij The digitally controlled phase shifter and digitally controlled attenuator of the signal channel enable the signal to be fed to antenna element a. ij and b ij Radio frequency signals have the same phase and the same amplitude, that is:

[0039]

[0040] |I aij |=|I bij | (2)

[0041] In the formula, i = 1, 2, ..., m; j = 1, 2, ..., n.

[0042] like Figure 4 As shown in (a), at this time, the horizontal polarization components are opposite and cancel each other out, while the vertical polarization components are the same, and the superposition results in the overall vertical polarization.

[0043] (8) When conducting horizontal polarization radiation field tests, the amplitude and phase controller is controlled by the system software to adjust Sa. ij Sb ij The digitally controlled phase shifter and digitally controlled attenuator of the signal channel enable the signal to be fed to antenna element a. ij and b ij Radio frequency signals have opposite phases but the same amplitude, that is:

[0044]

[0045] |I aij |=|I bij | (4)

[0046] In the formula, i = 1, 2, ..., m; j = 1, 2, ..., n.

[0047] like Figure 4 As shown in (b), at this time, the horizontal polarization components are in the same direction and are strengthened after superposition, while the vertical polarization components are in opposite directions and cancel each other out. After superposition, the whole exhibits horizontal polarization.

[0048] (9) Each radiation unit T can be adjusted as needed. ij The phase difference is used to adjust the radiation pattern of the array antenna, so that the illumination beam can scan within a certain range in the elevation and horizontal directions.

[0049] Example

[0050] To simulate a high-intensity radio frequency radiation field in a certain frequency band, assuming the system operates in the frequency range of 4GHz to 8GHz, the peak field strength requirements at a distance of 1m from the transmitting antenna are shown in Table 1:

[0051] Table 1 System Peak Field Strength Requirements (at a distance ≥1m from the transmitting antenna)

[0052] Frequency range (GHz) Peak electric field strength (V / m) 3dB electric field strength requirement (V / m) 4～6 ≥21000 ≥14850 6～7 ≥15000 ≥10610 7～8 ≥8000 ≥5660

[0053] The diameter of the focal spot for a 3dB field strength is not less than 0.3m.

[0054] Based on the above system requirements, and considering the power amplifier components and system layout design, the antenna array adopts a 96-element real-element radiating element design. Each radiating element is formed by integrally machining two orthogonally polarized all-metal Vivaldi antennas (e.g., Figure 2 As shown), a 10×10 radiating element antenna array is used as the basis, with a total of 200 Vivaldi antenna elements. The Vivaldi antenna elements have a VSWR ≤ 2 and a gain of 6dB to 11.5dB in the frequency range of 4GHz to 8GHz. One radiating element is placed at each of the four corners of the array as a virtual element. To reduce the active VSWR of the antenna elements and ensure that the antenna element radiation pattern is not distorted, two columns of virtual element antennas are designed at the edge of the array, such as... Figure 5 As shown.

[0055] The peak output power of a single final stage power amplifier is not less than 1kW in the 4GHz to 6GHz range and not less than 0.9kW in the 6GHz to 8GHz range.

[0056] The radiation field distribution of the rectangular array was optimized to achieve a near-circular distribution at a distance of 1m from the array surface.

[0057] The antenna array was modeled and simulated using the high-frequency electromagnetic simulation software ANSYS HFSS. A field strength observation surface with a diameter of 300 mm was set 1 m in front of the array aperture to observe the field strength distribution on the aperture surface.

[0058] Keeping the output power of each radiating real element constant (which is the saturated output power of the power amplifier module), the phase is controlled by a genetic algorithm, with the phase value varying between 0 and π, thereby optimizing the near-field radiation pattern and obtaining a beam shape with lower sidelobes and a relatively flat top of the main lobe.

[0059] Taking a 10-element linear array as an example for verification, the typical phase optimization distribution results obtained by the genetic algorithm are shown in Table 2.

[0060] Table 2 Typical results of phase optimization distribution

[0061] Array element Phase distribution (rad) 1 0 2 0.5718 3 0.5681 4 0.5725 5 0.5699 6 0.5699 7 0.5725 8 0.5681 9 0.5718 10 0

[0062] The field distribution within a 0.3m diameter region 1m in front of the array antenna normal was simulated, and the field distribution cloud maps at each frequency point were obtained as follows: Figures 6-10 As shown, the peak field strength and edge field strength within the focal spot range of 0.3m at a distance of 1m from the array surface along the normal direction both meet the requirements of Table 1.

[0063] By adjusting the phase difference between two antenna elements in the radiating element through system software, the polarization characteristics of the radiation field can be easily adjusted. When antenna element a... ij and b ijWhen in phase, the array antenna radiates a vertically polarized field; when antenna element a ij and b ij When the phase is reversed, the array antenna radiates a horizontally polarized field.

[0064] Because the path length of each RF signal from the signal source to the transmitting antenna element varies (caused by circuit technology, device characteristics, feeder length, etc.), the amplitude and phase differences caused by these factors should be calibrated before amplitude and phase adjustment. The digitally controlled phase shifter and digitally controlled attenuator operate in a step-by-step mode, and the final adjustment effect cannot be absolutely in-phase or out-of-phase; a certain phase error will exist, affecting the purity of linear polarization. The amplitude consistency of the antenna element's radiation level will affect the direction of linear polarization. Using high-performance digitally controlled phase shifters and digitally controlled attenuators can control the errors in polarization purity and polarization direction within an acceptable experimental range.

[0065] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0066] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A strong radiation field simulation system for a variable polarization array antenna based on phase-shift control, characterized in that, include: Preamplifier, power divider, amplitude and phase controller, and planar array antenna; The planar array antenna includes several radiating elements, each of which consists of two orthogonally arranged antenna elements. Each antenna element includes a digitally controlled phase shifter, a digitally controlled attenuator, a final-stage power amplifier, an isolator, and a transmitting antenna connected in sequence. The input radio frequency signal is amplified by the pre-amplifier and then distributed by the power divider, expanding the number of radio frequency signal channels to the number of antenna elements. The amplitude of each signal channel meets the drive level of the final stage power amplifier and enables the final stage power amplifier to generate sufficient output power. Each radio frequency signal output by the power divider is fed to the corresponding transmitting antenna after passing through a digitally controlled phase shifter, a digitally controlled attenuator, a final stage power amplifier, and an isolator. Each transmitting antenna radiates into the air and synthesizes to generate a high-intensity radio frequency radiation field that meets the requirements in the designated area. For vertically polarized radiation field tests or horizontally polarized radiation field tests, the phase and amplitude of the RF signal fed to the antenna unit are adjusted by controlling the amplitude and phase controller and adjusting the digitally controlled phase shifter and digitally controlled attenuator of each RF signal channel output by the power divider.

2. The system according to claim 1, characterized in that, The polarization directions of the two orthogonally arranged antenna elements in the radiating unit are symmetrically arranged at a 45-degree angle to the vertical direction.

3. The system according to claim 2, characterized in that, The two orthogonally arranged antenna elements in the radiating unit are manufactured as a single unit, and are powered by two coaxial ports at the bottom.

4. The system according to claim 3, characterized in that, The two orthogonally arranged antenna elements in the radiating unit are either Vivaldi antennas or double-ridged horn antennas with a working bandwidth of not less than one octave and good linear polarization characteristics.

5. The system according to any one of claims 1 to 4, characterized in that, The final stage power amplifier uses the same model of RF power amplifier module with basically the same amplitude and phase characteristics; the isolator uses the same model of isolator with basically the same amplitude and phase characteristics.

6. The system according to claim 5, characterized in that, When conducting vertically polarized radiation field tests, the phase shifter and attenuator of each radio frequency signal channel output by the power divider are adjusted by controlling the amplitude and phase controller, so that the radio frequency signals of the two orthogonally arranged antenna elements fed into the radiation element have the same phase and amplitude.

7. The system according to claim 5, characterized in that, When conducting horizontal polarization radiation field tests, the phase shifter and attenuator of each radio frequency signal channel output by the power divider are adjusted by controlling the amplitude and phase controller, so that the radio frequency signals of the two orthogonally arranged antenna elements fed into the radiation element have opposite phases and the same amplitude.

8. The system according to claim 1, characterized in that, By adjusting the phase difference of each radiating element, the radiation pattern of the planar array antenna is adjusted, enabling the illumination beam to scan within a certain range in both the elevation and horizontal directions.

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