Gain improvement type antenna for high-power microwave system and parameter determination method

Abstract

The invention relates to the technical field of antennas, and discloses a gain-improved antenna for a high-power microwave system and a parameter determination method, so as to synchronously improve the power capacity and gain after selecting an anti-breakdown dielectric substrate with a high dielectric constant. The antenna comprises a gradient feed balun which is carried on the back surface of a dielectric substrate and is connected with an inner conductor probe of a coaxial line, wherein an outer conductor of the coaxial line is connected with a part, which is deployed on the front surface of the dielectric substrate, of a Vivaldi antenna; the dielectric constant of the dielectric substrate is greater than or equal to 10.2; wherein inclined rectangular grooves with the same size and shape are formed in the two sides of the part, located on the front face of the dielectric substrate, of the Vivaldi antenna, and a metasurface unit of a snowflake-like structure is printed in the middle of the upper portion between a left gradual change curve and a right gradual change curve, so that the power capacity in the target working frequency band of the S wave band and the C wave band is larger than 8 MW, and the radiation gain is obviously improved.

Description

Technical Field

[0001] The present invention relates to the field of antenna technology, and in particular to a gain-improved antenna for a high-power microwave system and a parameter determination method. Background Art

[0002] High-power microwave systems are generally composed of three modules: pulse power drive source, microwave source and radiation antenna. Among them, the working bandwidth of the ultra-wideband pulse power drive source working in the X-band generally does not exceed 1GHz; high-power microwave antenna refers to a radiation antenna that works in the range of 0.3-300GHz and has an input signal amplitude exceeding 100MW. Since the pulse power drive source at the back end of the high-power microwave antenna will output an extremely high-power pulse, the power capacity of the radiation antenna used in the high-power microwave system within the working frequency band is generally more than 8000W to prevent the electromagnetic wave transmitting device from being broken down.

[0003] The Vivaldi antenna is a special tapered slot antenna that uses an exponentially tapered slot line printed on the same side of a dielectric substrate to achieve a transition from a small size to a large size. Therefore, the Vivaldi antenna also has an extremely wide operating bandwidth. The antipodal Vivaldi antenna (also known as the "antipodal Vivaldi antenna") prints two exponentially tapered slot line oscillators on both sides of a dielectric substrate. Compared with ordinary Vivaldi antennas, the antipodal Vivaldi antenna has the advantages of achieving stable gain, improved cross-polarization, and a compact structure. It is widely used in wireless communications and radar detection. However, ordinary Vivaldi antennas are generally loaded on dielectric substrates with a dielectric constant of 2-5. Their power capacity is generally low, only 1-3MW, and they are easily broken down in high-power microwave systems. Therefore, they cannot be used in high-power microwave systems.

[0004] The power capacity calculation method of microwave devices at a certain frequency point is: Among them, P in is the input power, which is set to 0.5W in the electromagnetic simulation software; E pr is the breakdown field strength in air environment, which is 3*10 6 V / m; E max is the maximum electric field strength value of the microwave device at this frequency. It can be seen that the power capacity of the microwave device is closely related to its electric field strength and is inversely proportional. Therefore, in order to improve the power capacity, it is necessary to reduce the electric field strength of the microwave device within the working frequency band as much as possible. At the same time, in the process of reducing the power capacity, there is often a situation of losing one thing while taking another into account, which affects the final product performance; it is necessary to study a highly versatile antenna and parameter determination method to simultaneously improve the power capacity and gain after selecting a high dielectric constant dielectric substrate that is anti-breakdown. Summary of the invention

[0005] The present invention aims to disclose a gain-improved antenna for a high-power microwave system and a parameter determination method, so as to simultaneously improve the power capacity and gain after selecting a high dielectric constant dielectric substrate that is anti-breakdown.

[0006] To achieve the above-mentioned purpose, the gain-improved antenna for a high-power microwave system disclosed in the present invention comprises:

[0007] A gradient-feed balun mounted on the back of a dielectric substrate and connected to an inner conductor probe of a coaxial line, wherein an outer conductor of the coaxial line is connected to a portion of a Vivaldi antenna deployed on the front of the dielectric substrate; the dielectric constant of the dielectric substrate is greater than or equal to 10.2;

[0008] Among them, the Vivaldi antenna is located on both sides of the front part of the dielectric substrate with oblique rectangular grooves of the same size and shape, and a metasurface unit with a snowflake structure is printed in the upper center position between the left and right gradient curves, so that the power capacity in the target operating frequency band of 2.64-6.24GHz is greater than 8MW and the gain is 6.56-8.15dBi.

[0009] Preferably, the dielectric substrate is made of TP-1020 material.

[0010] Preferably, the tapered feed balun includes a trapezoidal tapered feed line, a transverse rectangular feed line and a fan-shaped balun.

[0011] Preferably, the long side length, short side length and height of the trapezoidal gradient feed line 2 are 2.2 mm, 0.8 mm and 8.3 mm respectively; the length and width of the transverse rectangular feed line 3 are 5.9 mm and 0.9 mm respectively; the side length and angle of the fan-shaped balun 4 are 4.9 mm and 90° respectively.

[0012] Preferably, the length and width of the Vivaldi antenna are 90 mm and 53 mm, the radius of the circular slot is 4.9 mm, and the distance between the center of the circular slot and the feeding level is 5.7 mm; the parameter equation of one of the exponential gradient curves in the toe distribution is: y=ae x +b; if the center of the circular slot is taken as the coordinate origin, the length direction of the Vivaldi antenna is the Y axis, and the width direction is the X axis, then the values ​​of a and b are -97 and 91 respectively.

[0013] Preferably, the length and width of the oblique rectangular grooves are 15 mm and 1.5 mm respectively, the spacing between the oblique rectangular grooves is 15 mm, and the downward rotation angle is 40°.

[0014] Preferably, the snowflake-like structure of the super surface unit is symmetrical based on the symmetry axis between the left and right gradient curves, and includes at least two levels, the snowflake-like structures of two adjacent levels increase from bottom to top, and the internal arrangement rule of the snowflake structure at each level is two rows of the same number.

[0015] Preferably, the snowflake-like structure is formed by rotating a strip with a length and a width of 1.85 mm and 0.35 mm respectively around its own center by ±60°.

[0016] To achieve the above object, the present invention further discloses a method for determining parameters of a gain-improved antenna for a high-power microwave system, which is used to prepare the above-mentioned gain-improved antenna for a high-power microwave system, comprising:

[0017] Select dielectric substrates with dielectric constants that prevent breakdown to improve the power capacity of the antenna - design the corresponding parameters of the exponential curve and circular slot on the front of the Vivaldi antenna, determine the approximate size of the antenna, and then determine the working frequency band range of the antenna - design the corresponding parameters of the feed balun, and coarsely adjust the impedance matching performance of the antenna - design the corresponding parameters of the rectangular slot and the snowflake-like structure, coarsely adjust the radiation characteristics of the antenna, and improve the gain - fine-tune each parameter until the antenna meets the requirements of working bandwidth, resonance depth, power capacity and radiation gain at the same time.

[0018] The present invention has the following beneficial effects:

[0019] 1. The Vivaldi antenna is designed with a high dielectric constant substrate, which improves the power capacity of the antenna, so that it can be used as a radiating antenna in high-power microwave systems, and is also conducive to the miniaturization of the antenna.

[0020] 2. Loading oblique rectangular slots on the two arms of the Vivaldi antenna improves the impedance characteristics and power capacity of the antenna at low frequencies and realizes the miniaturization of the antenna.

[0021] 3. A snowflake-like periodic structure is loaded above the exponential opening of the Vivaldi antenna as a director structure, which directs the electromagnetic energy from the radiating oscillator to the influencing structure, improves the radiation gain of the antenna, and to a certain extent compensates for the gain loss caused by loading a high dielectric constant substrate.

[0022] The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 It is an iterative process among the four different solutions disclosed in the embodiments of the present invention.

[0025] Figure 2 It is a structural schematic diagram of the back side of the dielectric substrate disclosed in an embodiment of the present invention.

[0026] Figure 3 It is a structural schematic diagram of the front side of the dielectric substrate disclosed in an embodiment of the present invention.

[0027] Figure 4 It is a schematic diagram comparing the return loss simulation results between several different solutions disclosed in the embodiments of the present invention.

[0028] Figure 5 It is a schematic diagram comparing power capacity simulation results among several different solutions disclosed in the embodiments of the present invention.

[0029] Figure 6 It is a schematic diagram comparing maximum gain simulation results among several different schemes disclosed in the embodiments of the present invention.

[0030] Figure 7 It is a physical picture of the gain-improved antenna for a high-power microwave system disclosed in an embodiment of the present invention.

[0031] Figure 8 It is a schematic diagram comparing the measured and simulated standing wave ratio results disclosed in the embodiment of the present invention.

[0032] Fig. 9 It is a schematic diagram comparing the gain results of actual measurement and simulation disclosed in the embodiment of the present invention. DETAILED DESCRIPTION

[0033] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0034] Example 1

[0035] This embodiment discloses a gain-improved antenna for a high-power microwave system.

[0036] like Figure 1 As shown, in the iterative process of the scheme of this embodiment. Ant I is a Vivaldi antenna based on an ordinary dielectric substrate. Its power capacity is less than 4MW within the working frequency band, which cannot meet the demand of high-power microwave systems for device power capacity. In order to improve the power capacity of Ant I, the dielectric substrate material of Ant I is replaced with TP-1020 material with a dielectric constant of 10.2, and the power capacity of Ant II is increased to more than 8MW. However, due to the loading of the high dielectric constant substrate, the impedance and radiation characteristics of Ant II deteriorate, which is manifested in the increase of the standing wave ratio of the antenna and the decrease of the achieved gain. Therefore, on the basis of Ant II, a snowflake-like periodic structure and an oblique rectangular gap are loaded respectively to form Ant III and the antenna of this embodiment, which plays a role in improving the impedance characteristics and radiation characteristics of the antenna.

[0037] like Figure 2 and Figure 3 As shown, the antenna disclosed in this embodiment includes:

[0038] A gradient-fed balun is mounted on the back of a dielectric substrate 1 and connected to the inner conductor probe of a coaxial line, the gradient-fed balun comprising a trapezoidal gradient feed line 2, a transverse rectangular feed line 3 and a sector balun 4; the outer conductor of the coaxial line is connected to a portion 5 of the Vivaldi antenna deployed on the front of the dielectric substrate; the dielectric constant of the dielectric substrate is greater than or equal to 10.2; wherein, the Vivaldi antenna is located on both sides of the front portion of the dielectric substrate and is provided with oblique rectangular grooves 6 of the same size and shape, and a metasurface unit 7 of a snowflake-like structure is printed in the upper center position between the left and right gradient curves, so that the power capacity in the target operating frequency band of 2.64-6.24 GHz is greater than 8MW and the gain is between 6.56-8.15dBi.

[0039] Preferably, the dielectric substrate is made of TP-1020 material.

[0040] In a specific product corresponding to this embodiment, the long side length, short side length and height of the trapezoidal gradient feed line 2 are 2.2mm, 0.8mm and 8.3mm respectively; the length and width of the horizontal rectangular feed line 3 are 5.9mm and 0.9mm respectively; the side length and angle of the fan-shaped balun 4 are 4.9mm and 90° respectively. The length and width of the Vivaldi antenna are 90mm and 53mm, the radius of the circular slot is 4.9mm, and the distance from the center of the circular slot to the feed level is 5.7mm. The left and right exponential gradient curves are toe-to-toe distribution, and the parameter equation of one exponential gradient curve is: y=ae x +b; if the center of the circular slot is the origin of the coordinates, the length direction of the Vivaldi antenna is the Y axis, and the width direction is the X axis, then the values ​​of a and b are -97 and 91, respectively. In addition, the length and width of the oblique rectangular slot are 15 mm and 1.5 mm, respectively, the spacing between the oblique rectangular slots is 15 mm, and the downward rotation angle is 40°.

[0041] In this embodiment, the snowflake-like structure is formed by a strip with a length and width of 1.85 mm and 0.35 mm respectively rotated around its own center by ±60°, wherein the snowflake-like structure of the metasurface unit is symmetrical based on the symmetry axis between the left and right gradient curves, and includes at least two levels, and the two adjacent levels of snowflake-like structures increase from bottom to top, and the internal arrangement rule of each level of snowflake structure is two rows of the same number above and below.

[0042] Figure 4The return loss simulation result of the product designed based on the above dimensions in this embodiment shows that the -10dB impedance bandwidth of the Vivaldi antenna loaded with a high dielectric constant covers 2.57-6.70GHz; and the maximum electric field strength of the product at two different frequencies of 4GHz and 6GHz is 20645.8V / m and 20177.3V / m respectively, which is much lower than 3*10 6 V / m.

[0043] Figure 5 The power capacity simulation results of this embodiment are compared with those of the Vivaldi antenna loaded with a common dielectric substrate. The power capacity of this embodiment is greater than 8MW in the range of 2.64-6.24GHz, and the power capacity at 2.8GHz reaches a maximum of 15MW, while the power capacity of the Vivaldi antenna loaded with a common dielectric substrate does not exceed 3.2MW in the working frequency band. It is worth noting that the power capacity of some working frequency bands in Ant III is less than 8MW, so the oblique rectangular slots used in this embodiment also have unexpected technical effects in improving power capacity.

[0044] Figure 6 The maximum gain simulation results of this embodiment and the iterative version are compared. At 2.8GHz, the realized gain of this embodiment can be increased to 6dBi compared with Ant II; the overall realized gain in the target frequency band is significantly improved, and the volatility in the working frequency band is significantly better. In addition, through the simulation results of the E-plane radiation pattern at different frequency points, it can be seen that the H-plane radiation pattern of this embodiment can basically achieve bilateral symmetry, while the radiation main lobe of the E-plane radiation pattern will be offset due to the asymmetry of the feeding position.

[0045] Figure 7 This is a physical picture of the present invention. For details, see Figure 8 and Fig. 9 .in, Figure 8 The standing wave ratio comparison results show that the measured and simulated standing wave ratio results are highly consistent. The measured bandwidths of standing wave ratios below 2 and below 2.5 are 2.28-6.54 GHz and 2.21-7.17 GHz, respectively. Fig. 9 The actual measured and simulated gain and gain improvement are as follows: the actual measured gain of this embodiment (i.e., Ant IV) within the working frequency band is 6.56-8.15dBi; compared with the simulated gain result of Ant II, the actual measured gain of this embodiment within the working frequency band is improved by 0.66-5.96dBi.

[0046] Example 2

[0047] This embodiment discloses a method for determining parameters of a gain-improved antenna for a high-power microwave system, which is used to prepare the gain-improved antenna for a high-power microwave system described in the above embodiment, comprising:

[0048] Select dielectric substrates with dielectric constants that prevent breakdown to improve the power capacity of the antenna - design the corresponding parameters of the exponential curve and circular slot on the front of the Vivaldi antenna, determine the approximate size of the antenna, and then determine the working frequency band range of the antenna - design the corresponding parameters of the feed balun, and coarsely adjust the impedance matching performance of the antenna - design the corresponding parameters of the rectangular slot and the snowflake-like structure, coarsely adjust the radiation characteristics of the antenna, and improve the gain - fine-tune each parameter until the antenna meets the requirements of working bandwidth, resonance depth, power capacity and radiation gain at the same time.

[0049] In summary, the devices and methods disclosed in the above two embodiments of the present invention respectively have at least the following beneficial effects:

[0050] 1. The Vivaldi antenna is designed with a high dielectric constant substrate, which improves the power capacity of the antenna, so that it can be used as a radiating antenna in high-power microwave systems, and is also conducive to the miniaturization of the antenna.

[0051] 2. Loading oblique rectangular slots on the two arms of the Vivaldi antenna improves the impedance characteristics and power capacity of the antenna at low frequencies and realizes the miniaturization of the antenna.

[0052] 3. A snowflake-like periodic structure is loaded above the exponential opening of the Vivaldi antenna as a director structure, which directs the electromagnetic energy from the radiating oscillator to the influencing structure, improves the radiation gain of the antenna, and to a certain extent compensates for the gain loss caused by loading a high dielectric constant substrate.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A gain-improved antenna for a high-power microwave system, characterized in that: include: A gradient-feed balun mounted on the back of a dielectric substrate and connected to an inner conductor probe of a coaxial line, wherein an outer conductor of the coaxial line is connected to a portion of a Vivaldi antenna deployed on the front of the dielectric substrate; the dielectric constant of the dielectric substrate is greater than or equal to 10.2; Among them, the Vivaldi antenna is located on both sides of the front part of the dielectric substrate with oblique rectangular grooves of the same size and shape, and a metasurface unit with a snowflake structure is printed in the upper center position between the left and right gradient curves, so that the power capacity in the target operating frequency band of 2.64-6.24GHz is greater than 8MW and the gain is 6.56-8.15dBi.

2. The gain-improved antenna for a high-power microwave system according to claim 1, characterized in that: The dielectric substrate is made of TP-1020 material.

3. The gain-improved antenna for a high-power microwave system according to claim 2, characterized in that: The tapered feed balun includes trapezoidal tapered feed line, transverse rectangular feed line and fan-shaped balun.

4. The gain-improved antenna for a high-power microwave system according to claim 3, characterized in that: The long side length, short side length and height of the trapezoidal gradient feed line 2 are 2.2 mm, 0.8 mm and 8.3 mm respectively; the length and width of the transverse rectangular feed line 3 are 5.9 mm and 0.9 mm respectively; the side length and angle of the fan-shaped balun 4 are 4.9 mm and 90° respectively.

5. The gain-improved antenna for a high-power microwave system according to claim 4, characterized in that: The length and width of the Vivaldi antenna are 90 mm and 53 mm, the radius of the circular slot is 4.9 mm, and the distance between the center of the circular slot and the feeding level is 5.7 mm. The parameter equation of one of the exponential gradient curves of the toe distribution is: y = ae x +b; if the center of the circular slot is taken as the coordinate origin, the length direction of the Vivaldi antenna is the Y axis, and the width direction is the X axis, then the values ​​of a and b are -97 and 91 respectively.

6. The gain-improved antenna for a high-power microwave system according to claim 5, characterized in that: The length and width of the oblique rectangular groove are 15 mm and 1.5 mm respectively, the spacing between the oblique rectangular grooves is 15 mm, and the downward rotation angle is 40°.

7. The gain-improved Vivaldi antenna for a high-power microwave system according to any one of claims 1 to 6, characterized in that: The snowflake-like structure of the super surface unit is symmetrical based on the symmetry axis between the left and right gradient curves, and includes at least two levels. The snowflake-like structures of two adjacent levels increase from bottom to top, and the internal arrangement rule of the snowflake structure at each level is two upper and lower rows of the same number.

8. The gain-improved antenna for a high-power microwave system according to claim 7, characterized in that: The snowflake-like structure is formed by rotating a strip with a length of 1.85 mm and a width of 0.35 mm around its own center by ±60°.

9. A method for determining parameters of a gain-improved antenna for a high-power microwave system, used to prepare the gain-improved antenna for a high-power microwave system as claimed in any one of claims 1 to 8, characterized in that: include: Select dielectric substrates with dielectric constants that prevent breakdown to improve the power capacity of the antenna - design the corresponding parameters of the exponential curve and circular slot on the front of the Vivaldi antenna, determine the approximate size of the antenna, and then determine the working frequency band range of the antenna - design the corresponding parameters of the feed balun, and coarsely adjust the impedance matching performance of the antenna - design the corresponding parameters of the rectangular slot and the snowflake-like structure, coarsely adjust the radiation characteristics of the antenna, and improve the gain - fine-tune each parameter until the antenna meets the requirements of working bandwidth, resonance depth, power capacity and radiation gain at the same time.

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