A transient electromagnetic pulse transmitting array antenna with high synthesis efficiency and optimization method

Abstract

The present invention relates to a transient electromagnetic pulse transmitting array antenna with high synthesis efficiency and an optimization method, belonging to the field of antenna technology. By using a Vivaldi antenna unit array, the number and spacing of the array antennas are optimized to make the array aperture nearly square, the path difference of the multi-path radiation pulses small, and the synthetic peak electric field in the far-field radiation field high. The antenna uses a dielectric substrate with a low dielectric constant, which reduces the transmission and radiation loss of transient electromagnetic pulses, thereby improving the synthesis efficiency. Compared with linear, rectangular or triangular array arrangements, with a nearly square array aperture, in the far-field radiation, the phase difference caused by the path difference of each antenna unit is smaller, the synthetic electric field is larger, and the synthesis efficiency is higher.

Description

Technical Field

[0001] The present invention belongs to the field of antenna technology, and in particular relates to a transient electromagnetic pulse transmitting array antenna with high synthesis efficiency and an optimization method thereof. Background Art

[0002] High-power microwave technology continues to develop towards high efficiency, high peak power, solidification, compact size, and wide bandwidth coverage. Traditional approaches that rely on increasing the aperture of a single antenna and boosting the transmit power are no longer able to meet the system's high peak transmit power requirements, especially for solid-state electromagnetic pulse sources.

[0003] Power combining achieves high-power radiation by synthesizing multiple relatively weak signals. Free-space power combining is a form of power combining. Its advantage is that it does not require high power capacity of a single solid-state source and radiating antenna. The system's combining efficiency is almost independent of the number of devices, making it suitable for high-power output from multiple devices.

[0004] In the early days, high-efficiency spatial synthesis of transient electromagnetic pulses was difficult due to limitations in antenna power capacity, microwave source output pulse width, and synchronization accuracy. Furthermore, the systems were bulky and difficult to integrate. In recent years, the continuous development and improvement of high-power transient pulse source technology, optoelectronic synchronization technology, time-domain antenna theory, and transient electromagnetic pulse transmission theory have made high-efficiency synthesis of transient electromagnetic pulses feasible. Summary of the Invention

[0005] The technical problems to be solved by the present invention are:

[0006] Aiming at the problem of high-efficiency emission and synthesis of transient electromagnetic pulses generated by solid-state microwave sources, a Vivaldi array antenna is proposed to improve the synthesis efficiency of multi-path transient electromagnetic pulses in free space.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A transient electromagnetic pulse transmitting array antenna with high synthesis efficiency is characterized by comprising m×n antipodal Vivaldi antenna units, wherein the array spacing of the m×n antenna units along the x direction is dx, and the array spacing along the y direction is dy. The values ​​of m, n, dx, and dy of the array antenna are optimized to make the array aperture nearly square, the path difference of multi-path radiation pulses is small, and the synthetic peak electric field in the far-field radiation field is high.

[0009] A further technical solution of the present invention is as follows: the heel-to-heel Vivaldi antenna unit comprises an upper metal sheet, a dielectric substrate, a lower metal sheet and a feed connector; the upper metal sheet and the lower metal sheet are etched on the upper surface and the lower surface of the dielectric substrate respectively, and the feed connector

[0010] A further technical solution of the present invention is that the inner and outer edge shapes of the upper metal sheet and the lower metal sheet are determined by the exponential curve equation y=c1e Ax +c2 is determined, where (x1, y1) and (x2, y2) are the starting and ending points of the exponential curve, and A is the opening rate of the exponential curve, including the opening rate A of the outer exponential curve. out and the opening rate of the inner exponential curve A in ; The upper edge of the feed balun is a quarter ellipse line, the semi-major axis length of the ellipse line is D, and the semi-minor axis length is F.

[0011] Further technical solution of the present invention: Optimizing the opening rate A of the external exponential curve out and the opening rate of the inner exponential curve A in , D, F and slot width t1 are selected so that the antenna has the optimal voltage conversion coefficient.

[0012] A further technical solution of the present invention: the feeding connector is an SMA connector.

[0013] A further technical solution of the present invention is that the dielectric substrate adopts a low dielectric constant plate material, which has low transmission and radiation losses for high peak electric fields.

[0014] A method for optimizing a transient electromagnetic pulse transmitting array antenna with high synthesis efficiency, characterized by comprising:

[0015] Optimize the values ​​of m, n, dx, and dy of the array antenna to make the array aperture nearly square, the path difference of multi-path radiation pulses small, and the synthetic peak electric field in the far-field radiation field high;

[0016] Optimize the opening rate A of the external exponential curve out and the opening rate of the inner exponential curve A in , D, F and slot width t1 are selected so that the antenna has the optimal voltage conversion coefficient.

[0017] The beneficial effects of the present invention are:

[0018] The present invention provides a transient electromagnetic pulse transmitting array antenna with high synthesis efficiency, which has the following beneficial effects:

[0019] According to the formula The steeper the pulse wave front, the richer the high-frequency content. The antipodal Vivaldi array unit has broadband characteristics, which is conducive to the radiation of fast-front transient electromagnetic pulses. At the same time, under optimized parameter values, the voltage conversion efficiency of the antenna is further improved. The antenna uses a low-dielectric constant dielectric substrate, which has low transmission and radiation losses of transient electromagnetic pulses, thereby improving the synthesis efficiency. Compared with linear, rectangular or triangular array layouts, the phase difference caused by the wave path difference of each antenna unit in the near-square array aperture is smaller in the far radiation range, the synthetic electric field is larger, and the synthesis efficiency is higher.

[0020] As the pulse front and pulse half-peak width shorten, the array unit density can be increased under the same volume, further improving the radiation field peak and compactness of the synthetic array, which is beneficial to the integration of transient electromagnetic pulse emission systems.

[0021] The two metal plates of the antenna are located on both sides of the dielectric substrate. The power capacity is more than 10 times the breakdown field strength of air. The antenna has good power resistance characteristics and can withstand feed pulses with higher peak power. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0023] Figure 1 Schematic diagram of the structure of the antipodal Vivaldi antenna: (a) front; (b) back.

[0024] Figure 2 Different A in The inner exponential curve of the value.

[0025] Figure 3 10m, different A in Take the value of the radiated electric field of the Vivaldi antenna.

[0026] Figure 4 Schematic diagram of the transient electromagnetic pulse transmitting array antenna structure.

[0027] Figure 5 Radiation pulse waveform at 10 m: (a) excitation pulse leading edge 335 ps; (b) excitation pulse leading edge 140 ps. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only intended to illustrate the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0029] The voltage conversion efficiency of antenna elements, array layout, and single-path triggering time jitter are the main factors affecting the spatial power synthesis of transient electromagnetic pulse (TEMP) transmitting array antennas. This invention selects appropriate array element form, element structural parameters, and array layout to effectively improve the peak value of the synthesized electric field and power synthesis efficiency of the TEMP.

[0030] The present invention provides a high synthesis efficiency transient electromagnetic pulse transmitting array antenna, which adopts a Vivaldi array antenna and includes multiple identical antenna units. The antenna units are composed of an upper metal sheet, a dielectric substrate, a lower metal sheet and a feed connector. The upper metal sheet and the lower metal sheet are respectively etched on the upper surface and the lower surface of the dielectric substrate. The inner edge and outer edge shapes of the upper metal sheet and the lower metal sheet are determined by the exponential curve equation y=c1e Ax +c2 is determined, where (x1, y1) and (x2, y2) are the starting and ending points of the exponential curve, A is the opening rate of the exponential curve, the upper edge of the feed balun is a quarter ellipse line, the semi-major axis length of the ellipse line is D, and the semi-minor axis length is F.

[0031] Opening rate A of the external exponential curve of the antipodal Vivaldi antenna out and the opening rate of the inner exponential curve A in The values ​​of D, F and slot width t1 are selected to achieve the optimal voltage conversion coefficient of the antenna. The dielectric substrate of the antenna uses a low dielectric constant plate, which has low transmission and radiation losses for high peak electric fields.

[0032] The array spacing of m×n antenna units along the x direction is dx, and the array spacing along the y direction is dy. The values ​​of m, n, dx, and dy of the array antenna make the array aperture nearly square, the path difference of multi-path radiation pulses is small, and the synthetic peak electric field in the far-field radiation field is high.

[0033] The antipodal Vivaldi array antenna is used for the emission and spatial power synthesis of multi-path transient electromagnetic pulses.

[0034] Reference Figure 1 The width of the Vivaldi antenna is W = 281 mm, the height is H = 324.5 mm, the thickness of the dielectric substrate is 1.5 mm, the dielectric constant is 3.66, the loss tangent is 0.0037, the height h1 = 280 mm, h2 = 70 mm, the slot width w1 = 1.5 mm, the metal thickness t1 = 2 mm, D = 80 mm, F = 40 mm, the starting and ending points of the outer exponential curve are (0, 0) and (280, 140) respectively, and the starting and ending points of the inner exponential curve are (0, 1.5) and (70, 140) respectively. Substituting into the exponential curve equation y = c1e Ax+c2, we can get the equations of c1 and c2 about the opening rate respectively, and optimize the value A out and A in , so that the radiation electric field of the antenna unit is maximized.

[0035] Reference Figure 2 , take different A in When the value is , the changing trend of the inner exponential curve is different, and the height of the phase center of the Vivaldi antenna is different, which in turn affects the peak value of the electric field radiated by the antenna in the far zone.

[0036] Reference Figure 3 , A in When the values ​​are 0.012, 0.015, and 0.018 respectively, the radiation electric field at 10m reaches the maximum values ​​of 0.527V / m, 0.535V / m, and 0.515V / m respectively. The calculated voltage conversion coefficients are 0.745, 0.756, and 0.728, so A is taken. in =0.015. U represents the voltage conversion coefficient, r is the distance from the monitoring point to the antenna, E p is the peak value of the radiation electric field, U gmax is the peak value of the excitation pulse, R is the input impedance, P in is the input power, r = 10m, R = 50Ω, P in =1W.

[0037] Reference Figure 4 The number of antenna units along the x-axis and y-axis directions are 6 and 3 respectively. Among them, combined with the number of output interfaces and arrangement requirements of the solid-state microwave source, antenna units 2 and 17 are used as parasitic units without feeding. The unit spacing of the array antenna along the x-axis and y-axis directions is dx = 180 mm and dy = 290 mm. Under this number of antenna units and array spacing, the array aperture is nearly square. At a certain point on the far-field radiation axis, the phase difference of the radiation field of each antenna unit caused by the wave path difference is small, the synthetic electric field is larger, and the synthetic efficiency is higher.

[0038] Reference Figure 5 , each element of the array antenna is fed with transient pulses with leading edges of 335ps and 140ps respectively. The radiation fields at 10m reach 8.45V / m and 13.86V / m respectively, and the power combination efficiency of the 16 elements is 97.4% and 98.7% respectively.

[0039] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present invention, and these modifications or replacements should all be included in the scope of protection of the present invention.

Claims

1. A transient electromagnetic pulse transmitting array antenna with high synthesis efficiency, characterized in that: The invention comprises m×n anti-heel Vivaldi antenna units, wherein the array spacing of the m×n antenna units along the x direction is dx, and the array spacing along the y direction is dy. The values ​​of m, n, dx, and dy of the array antenna are optimized so that the array aperture is nearly square, the path difference of the multi-path radiation pulse is small, and the synthetic peak electric field in the far-field radiation field is high. The anti-heel Vivaldi antenna unit comprises an upper metal sheet, a dielectric substrate, a lower metal sheet, and a feed connector. The upper metal sheet and the lower metal sheet are respectively etched on the upper surface and the lower surface of the dielectric substrate, and the feed connector is connected to the upper metal sheet. The shapes of the inner and outer edges of the upper and lower metal sheets are determined by the exponential curve equation. Determine, among which, , , 、 are the starting and ending points of the exponential curve, A is the opening rate of the exponential curve, including the opening rate of the outer exponential curve and the opening rate of the inner exponential curve The upper edge of the feed balun is a quarter ellipse line, the semi-major axis length of the ellipse line is D, and the semi-minor axis length is F; the opening rate of the outer exponential curve is optimized and the opening rate of the inner exponential curve , D, F and slot width The value of makes the antenna have the optimal voltage conversion coefficient; the antipodal Vivaldi array antenna is used for the transmission and spatial power synthesis of multi-path transient electromagnetic pulses.

2. The high synthesis efficiency transient electromagnetic pulse transmitting array antenna according to claim 1, characterized in that: The feeding connector is an SMA connector.

3. The high synthesis efficiency transient electromagnetic pulse transmitting array antenna according to claim 1, characterized in that: The dielectric substrate adopts a low dielectric constant plate, which has small transmission and radiation losses for high peak electric fields.

4. A method for optimizing a transient electromagnetic pulse transmitting array antenna with high synthesis efficiency, characterized in that: The transient electromagnetic pulse transmitting array antenna with high synthesis efficiency as claimed in claim 1 comprises: Optimize the values ​​of m, n, dx, and dy of the array antenna to make the array aperture nearly square, the path difference of multi-path radiation pulses small, and the synthetic peak electric field in the far-field radiation field high; Optimize the opening rate of the external exponential curve and the opening rate of the inner exponential curve , D, F and slot width The value of makes the antenna have the optimal voltage conversion coefficient.

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