Ultra-wideband miniaturized Vivaldi antenna

Abstract

The invention belongs to the technical field of communication, and particularly relates to an ultra-wideband miniaturized Vivaldi antenna. The antenna comprises a dielectric substrate, wherein the upper surface of the dielectric substrate comprises a main body Vivaldi antenna, four resistors, two rectangular metal patches and an artificial surface plasma, wherein the main body Vivaldi antenna is provided with an exponential gradually-changed slot; a feed network is arranged on the lower surface and comprises six impedance conversion microstrip transmission lines, a fan-shaped transmission line and a circular groove; the main body antenna and the dielectric substrate are placed in a centered alignment manner, the four resistors are placed at the tail end of the main body antenna, and the rear sides of the resistors are connected with the two rectangular patches; the artificial surface plasma is placed in the main body antenna gradual change gap; and the multi-section impedance transformer and the microstrip-to-slot line structure of the feed network are aligned with the circular slot of the main body antenna. According to the invention, the ultra wide band, miniaturization and high radiation gain are realized by designing the main body antenna, slotting the edge, loading the resistor, carrying out the artificial surface plasma and the like. The working frequency band of the antenna ranges from 0.2 GHz to 18 GHz, and the antenna has the characteristic of miniaturization.

Description

Technical Field

[0001] The invention belongs to the technical field of communications, and in particular relates to an ultra-wideband miniaturized Vivaldi antenna. Background Art

[0002] With the development of wireless communication technology, high-performance wireless communication receivers have attracted widespread attention and have great applications in both civil and military fields. Integrated reconnaissance, jamming, detection and communication receivers are an inevitable trend in the development of receivers in the future due to their small size, high flexibility and powerful functions. Among them, integrated radar receivers for reconnaissance, jamming and communication need to have a very wide receiving bandwidth to obtain the required signals of various frequencies, and they must be miniaturized to make it more difficult for the receiver to be detected and have excellent mobility, which puts higher requirements on the receiving antenna.

[0003] In recent years, researchers have designed various types of antennas, which are divided into narrowband antennas, broadband antennas and ultra-wideband antennas according to frequency band characteristics; divided into omnidirectional and directional antennas according to the radiation performance of the antenna; and divided into linear polarization, dual linear polarization, circular polarization and dual circular polarization antennas according to the polarization mode of electromagnetic waves that the antenna can collect. The Vivaldi antenna is an exponentially tapered slot antenna, which belongs to the category of ultra-wideband antennas. It has good radiation performance, such as a wider frequency band, symmetrical directional pattern, and stable gain. At the same time, the antenna itself has a simple structure, low manufacturing cost and is easy to integrate. It is currently widely used in satellite communications, radar systems, electronic countermeasures and wireless communications. Summary of the invention

[0004] The object of the present invention is to provide an ultra-wideband miniaturized Vivaldi antenna capable of collecting frequencies in the range of 0.2 GHz to 18 GHz in an environment.

[0005] The ultra-wideband miniaturized Vivaldi antenna provided by the present invention can cover the 90-fold frequency band of 0.2 GHz to 18 GHz, and has the characteristics of ultra-wideband and miniaturization.

[0006] The ultra-wideband miniaturized Vivaldi antenna provided by the present invention has a structure as follows: Figure 1As shown, it includes a dielectric substrate 11, the upper surface of the substrate includes an exponentially tapered slotted main Vivaldi antenna (specifically a tapered slot metal patch) 1, four resistors 9-12 and two rectangular metal patches 7, and an artificial surface plasma 8; the lower surface of the substrate is a feeding network, which includes a 6-section impedance transformation microstrip transmission line (called a 6-section impedance transformer) 2, a fan-shaped microstrip line 3 and a circular slot 4; the main Vivaldi antenna 1 is aligned with the dielectric substrate 13 in the center, the four resistors 9-12 are placed at the end of the main Vivaldi antenna 1, and the back of the resistors are connected to the two rectangular patches 7; the artificial surface plasma 8 is placed in the middle of the tapered gap of the main Vivaldi antenna 1; the multi-section impedance transformer and microstrip slot line structure of the feeding network are aligned with the circular slot of the Vivaldi antenna.

[0007] The antenna, the artificial surface plasma 8, and the bottom feeding network are respectively closely attached to the upper and lower surfaces of the dielectric substrate 13, with no gap between them;

[0008] The gradient groove metal patch 1 in the upper antenna is aligned with the bottom of the dielectric substrate 13, and three grooves are opened in the middle center of the gradient groove metal patch 1: a circular groove 4, a rectangular groove 5 and an exponential gradient groove 6, and the three grooves are connected in sequence from bottom to top; two symmetrical rectangular grooves 14 are opened at the edge; the gradient groove metal patch 1 is connected to two resistors 11-12 at the rear end and two resistors 9-10 at the end; the resistors 9-10 are connected to a rectangular metal patch 7; the gradient groove metal patch 1 and the rectangular metal patch 7 are aligned with the left and right sides of the dielectric substrate 13; see Figure 2 .

[0009] In the lower layer feeding network, the first section of the 6 impedance transformation microstrip lines 2 is aligned with the bottom of the dielectric substrate 13, and each section of the impedance transformation microstrip line is connected end to end; the third section of the microstrip line is designed to be a right-angle turn; the last section of the microstrip line is connected to the fan-shaped microstrip line 3, and its end is aligned with the edge of the rectangular slot; see Figure 3 .

[0010] The artificial surface plasma 8 is located at the center of the rear end of the gradient groove; see Figure 2 The artificial surface plasma 8 has an I-shaped unit structure, which is composed of I-shaped units arranged periodically.

[0011] In the feeding network, 6 impedance transformers are designed to achieve impedance transformation from 50Ω to 100Ω, improve antenna impedance matching, and reduce losses; a fan-shaped microstrip line is added behind the impedance transformer, and a circular slot 4 is added behind the rectangular slot to make the slot line and the end of the microstrip line resonate, realize the discontinuous connection of the impedance from the microstrip line to the slot line, and achieve broadband within the target bandwidth;

[0012] In order to achieve broadband matching, an exponential gradient groove is designed on the gradient groove metal patch 1 for radiation; a symmetrical rectangular groove 14 is opened on the edge of the gradient groove metal patch 1 to extend the surface current path and reduce the resonance point frequency, thereby achieving the purpose of expanding the low-frequency bandwidth and improving the impedance matching of the low-frequency band; a lossy resistor 9-12 is added at the end of the gradient groove metal patch 1 to absorb the end current, thereby reducing the reflection coefficient of the low-frequency band, improving the impedance matching of the full frequency band, and achieving the purpose of miniaturization;

[0013] An artificial surface plasma 8 is added in the middle of the gradient groove metal patch 1 to improve the radiation gain in the high frequency band.

[0014] In the present invention, the dielectric substrate 13 is made of FR4 material with a dielectric constant of 4.4, a loss tangent of 0.015, a thickness of 0.8 mm, and a metal layer material of copper with a thickness of 0.035 mm;

[0015] In the present invention, the resistance of the four resistors 9-12 is 100Ω;

[0016] The ultra-wideband miniaturized Vivaldi antenna of the present invention has an operating frequency band of 0.2 GHz to 18 GHz and a size of 308×180×0.8 mm. 3 (length × width × height), i.e. 0.16λ0 × 0.28λ0 mm 2 (length × width), λ0 is the free space wavelength corresponding to the lowest frequency, which has the characteristics of miniaturization.

[0017] The present invention reasonably designs an ultra-wideband feeding network, including a multi-section impedance transformer and a microstrip slot line balun structure, so that it can receive electromagnetic waves of the target bandwidth; the present invention reasonably designs a Vivaldi antenna, and achieves ultra-wideband, miniaturization and high radiation gain through edge slotting, resistor loading and artificial surface plasma. The simulation results show that the antenna has a frequency range of 0.27GHz to 18GHz|S 11 |<-10dB at 0.2GHz |S 11 |<-6dB, the antenna has good radiation performance in the frequency band from 0.2GHz to 18GHz, and has good directivity in the entire working band. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the ultra-wideband miniaturized Vivaldi antenna of the present invention.

[0019] Figure 2 It is a front structural schematic diagram of the ultra-wideband miniaturized Vivaldi antenna of the present invention.

[0020] Figure 3 It is a schematic diagram of the reverse structure of the ultra-wideband miniaturized Vivaldi antenna of the present invention.

[0021] Figure 4 The antenna reflection coefficient simulation result of the ultra-wideband miniaturized Vivaldi antenna of the present invention.

[0022] Figures 5 to 10 The antenna radiation pattern simulation result of the ultra-wideband miniaturized Vivaldi antenna of the present invention. Figure 5 Corresponds to 0.2GHz; Figure 6 Corresponds to 2GHz; Figure 7 Corresponds to 6GHz; Figure 8 Corresponds to 10GHz; Fig. 9 Corresponds to 14GHz; Fig.10 Corresponding to 18GHz.

[0023] The numbers in the figure are: 1 is the top-layer gradient groove metal patch, 2 is the bottom-layer impedance transformation microstrip line, 3 is the bottom-layer fan-shaped microstrip line, 4 is the bottom-layer circular groove, 5 is the rectangular groove, 6 is the exponential gradient groove, 7 is the top-layer rectangular metal patch, 8 is the top-layer artificial surface plasma, 9-12 are the top-layer resistors, 13 is the dielectric substrate, and 14 is the edge-symmetrical rectangular groove. DETAILED DESCRIPTION

[0024] The present invention is further described below in conjunction with the accompanying drawings and embodiments: This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0025] like Figure 1-4 As shown, the novel ultra-wideband miniaturized Vivaldi antenna provided by the present invention has an operating frequency band of 0.2 GHz to 18 GHz. The whole is divided into three parts, including the antenna, the feeding network and the artificial surface plasma; the antenna size is 308×180×0.8mm 3 (length×width×height). This embodiment includes: a metal patch 1 with a gradient slot for the antenna (including a circular slot 4, a rectangular slot 5, an exponential gradient slot 6 and two symmetrical rectangular slots 14 at the edge), a rectangular metal patch 7, resistors 9-12; an impedance transformation microstrip line 2 and a fan-shaped microstrip line 3 for the feed network; and finally, an artificial surface plasma 8 and a dielectric substrate 13.

[0026] like Figure 1-4 As shown, the end opening size of the gradient groove metal patch 1 described in this embodiment is 160mm, which is determined by the lowest frequency of the working frequency band, and the rectangular groove width size of the gradient groove metal patch 1 is 1.4mm, which is determined by the highest frequency of the working frequency band; the curve formula of the exponential gradient groove is described as follows:

[0027] y=C1*e R*x +C2

[0028] Among them, C1 is 9.81297, C2 is -15.9383, and R is 0.01.

[0029] The symmetrical edge rectangular groove 14 of the gradient groove metal patch 1 is 10 mm wide, which extends the surface current path and reduces the resonance point frequency, thereby expanding the low-frequency bandwidth and improving the impedance matching of the low-frequency band; the rectangular metal patch 7 is 28.4 mm long and 10 mm wide; the added resistor 9-12 has a resistance of 100Ω, which absorbs the terminal current, reduces the reflection coefficient of the low-frequency band, improves the impedance matching of the full frequency band, and achieves the purpose of miniaturization.

[0030] In the feeding network, 6 sections of impedance transformer microstrip transmission line 2 are designed. The lengths of the first to sixth sections of impedance transformer are 50mm, 30mm, 15mm, 10mm, 8.6mm, and 8mm, respectively, and their sizes are determined by the center frequency wavelength; the widths of the first to sixth sections of impedance transformer are 1.5mm, 1.2mm, 0.9mm, 0.7mm, 0.5mm, and 0.35mm, respectively, to achieve impedance transformation from 50Ω to 100Ω, improve antenna impedance matching, and reduce losses; a fan-shaped microstrip line 3 is added behind the impedance transformer, with a radius of 9mm and an angle of 180°; the size of the rectangular slot 5 is 2×1.4mm 2 (length × width), a circular slot 4 with a radius of 20 mm is added behind it to make the slot line and the end of the microstrip line form resonance, realize the connection of the impedance discontinuity from the microstrip line to the slot line, and achieve broadband within the target bandwidth;

[0031] An artificial surface plasma 8 is added in the middle of the gradient groove of the gradient groove metal patch 1. Its unit is an I-shaped structure, which is composed of a periodic extension arrangement of the I-shaped units. Its dimensions are 2.4 mm in length, 5 mm in height, 0.5 mm in line width, and 23 in period number, which can improve the radiation gain in the high frequency band.

[0032] The dielectric constant of the FR4 dielectric substrate is 4.4, the loss tangent is 0.015, the thickness is 0.8mm, and the metal layer material is copper with a thickness of 0.035mm.

[0033] like Figure 1 As shown, the size of the ultra-wideband miniaturized Vivaldi antenna described in this embodiment is 308×180×0.8mm 3 (length × width × height), i.e. 0.16λ0 × 0.28λ0 mm 2 , λ0 is the free space wavelength corresponding to the lowest frequency, which has the characteristics of miniaturization.

[0034] like Figure 4As shown in FIG. 1 , the reflection coefficient of the ultra-wideband miniaturized Vivaldi antenna of this embodiment is given. The horizontal axis represents the frequency variable in GHz, and the vertical axis represents the reflection coefficient variable in dB. The simulation results show that the ultra-wideband miniaturized Vivaldi antenna of the present invention has |S11| < -10dB in the frequency range of 0.27GHz to 18GHz, and |S11| < -10dB at 0.2GHz. 11 |<-6dB, the relative impedance bandwidth is 193%, with ultra-wideband characteristics.

[0035] like Figure 5-10 As shown, the radiation characteristics of the ultra-wideband miniaturized Vivaldi antenna of this embodiment are given. The horizontal axis represents the frequency variable in GHz, and the left vertical axis represents the gain in dBi. The simulation results show that the ultra-wideband miniaturized Vivaldi antenna of the present invention has a gain of -13.3dBi at 0.2GHz, a gain of 6.42dBi at 2GHz, a gain of 10.1dBi at 6GHz, a gain of 8.68dBi at 10GHz, a gain of 3.91dBi at 14GHz, and a gain of 2.5dBi at 18GHz.

[0036] The technical solution of the present invention is not limited to the above-mentioned specific examples. For example, the present invention is an ultra-wideband miniaturized Vivaldi antenna operating at 0.2 GHz to 18 GHz. By changing the size, it can be applied to other bands. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. An ultra-wideband miniaturized Vivaldi antenna, characterized in that: The invention comprises a dielectric substrate (13), the upper surface of which comprises a main Vivaldi antenna with an exponentially tapered slot, namely a tapered slot metal patch (1), four resistors (9-12) and two rectangular metal patches (7), and an artificial surface plasma (8); the tapered slot metal patch (1) comprises a rectangular slot (5), an exponentially tapered slot (6) and an edge rectangular slot (14); the lower surface of the substrate is a feeding network, which comprises 6 impedance transformation microstrip transmission lines (2), a fan-shaped microstrip line (3) and a circular slot (4); the main Vivaldi antenna (1) is aligned with the dielectric substrate (13) in the center, four resistors (9-12) are placed at the end of the main Vivaldi antenna (1), and the rear of the resistors are connected to two rectangular patches (7); an artificial surface plasma (6) is placed in the middle of the gradient slot of the main Vivaldi antenna (1) to improve the radiation gain in the high frequency band; and the multi-section impedance transformer and microstrip slot line structure of the feeding network are aligned with the circular slot of the Vivaldi antenna.

2. The ultra-wideband miniaturized Vivaldi antenna according to claim 1, characterized in that: The antenna, the artificial surface plasma (8), and the bottom feeding network are respectively closely attached to the upper and lower surfaces of the dielectric substrate 13, with no gap between them; The gradient groove metal patch (1) in the upper antenna is aligned with the bottom of the dielectric substrate (13), and three grooves are opened at the center of the gradient groove metal patch (1): a circular groove (4), a rectangular groove (5) and an exponential gradient groove (6), and the three grooves are connected in sequence from bottom to top; the gradient groove metal patch (1) is connected to two resistors (11-12) at the rear end and two resistors (9-10) at the end; the resistors (9-10) are respectively connected to rectangular metal patches (7); the gradient groove metal patch (1) and the rectangular metal patch (7) are aligned with the left and right sides of the dielectric substrate (13); In the lower layer feeding network, the first impedance transformation microstrip line of the six impedance transformation microstrip lines (2) is aligned with the bottom of the dielectric substrate (11), and each impedance transformation microstrip line is connected end to end; the third impedance transformation microstrip line is designed to be a right-angle turn; the last impedance transformation microstrip line is connected to the fan-shaped microstrip line (3), and its end is aligned with the edge of the rectangular slot (5); The artificial surface plasma (8) is located at the center of the rear end of the gradient groove and is composed of an I-shaped structure with unit periodic extension arrangement.

3. The ultra-wideband miniaturized Vivaldi antenna according to claim 2, characterized in that: In the feeding network, 6 sections of impedance transformation microstrip lines are designed to achieve impedance transformation from 50Ω to 100Ω, so as to improve antenna impedance matching and reduce loss; a fan-shaped microstrip line (3) is added behind the impedance transformer, and a circular slot (4) is added behind the rectangular slot (5) so that the slot line and the ends of the microstrip line form resonance, so as to achieve the connection of the discontinuous impedance from the microstrip line to the slot line, and achieve broadband within the target bandwidth.

4. The ultra-wideband miniaturized Vivaldi antenna according to claim 3, characterized in that: An exponentially tapered groove is designed in a tapered groove metal patch (1) for radiation; a rectangular groove (14) is opened at the edge of the tapered groove metal patch (1) to extend the surface current path and reduce the resonance point frequency, thereby achieving the purpose of expanding the low-frequency bandwidth and improving the impedance matching of the low-frequency band; and a dissipation resistor (9-12) is added at the end of the tapered groove metal patch (1) to absorb the end current, thereby reducing the reflection coefficient of the low-frequency band and improving the impedance matching of the entire frequency band.

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