CN110783709A

CN110783709A - Opposite extension Vivaldi antenna based on slot correction structure loading

Info

Publication number: CN110783709A
Application number: CN201911022418.1A
Authority: CN
Inventors: 杜伯学; 宁江涛
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2019-10-25
Filing date: 2019-10-25
Publication date: 2020-02-11

Abstract

The invention discloses a butt-extension Vivaldi antenna loaded based on a slot correction structure, which loads the slot correction structure on the basis of an EGSA antenna; the SCA antenna comprises a dielectric substrate, a metal radiating plate, a microstrip balun, an elliptical slot line, an index gradient slot and a slot correction structure; the metal radiating pieces are respectively fixed on the top surface and the bottom surface of the dielectric substrate, and the impedance matching microstrip balun is composed of a linear gradient microstrip line and a metal patch provided with an elliptical slot line; the metal radiating sheet is provided with a horn-shaped opening and an index gradual change groove line which is symmetrical about a horizontal central axis of the metal radiating sheet, the outer side wall of the metal radiating sheet is provided with a corrugated index gradual change groove, and a groove correction structure is loaded at the index gradual change groove line of the EGSA.

Description

Opposite extension Vivaldi antenna based on slot correction structure loading

Technical Field

The invention belongs to the technical field of antennas, and particularly relates to an opposite extension Vivaldi antenna based on slot correction structure loading.

Background

With the development of communication technology, broadband, high-gain, and good-directivity antennas have attracted increasing attention. The Vivaldi antenna, i.e. the exponential tapered slot antenna, is an end-fire tapered slot antenna proposed by Gibson in 1979, the current of which is intensively distributed near the slot line which changes exponentially, and the slot lines with different widths correspondingly radiate electromagnetic waves with different frequencies. Theoretically, such an antenna can achieve a very wide operating bandwidth. In addition, Vivaldi antennas also have high gain and good end-fire performance. And thus is widely used in communication and electronic countermeasure systems. However, for the conventional antipodal Vivaldi antenna, the current on the resonant arm cannot flow along the slot line well, so that the directivity performance is poor.

Disclosure of Invention

The invention aims to solve the technical problem that a Vivaldi antenna has poor directivity, and provides a diagonal Vivaldi antenna (EGSA) with a slot correction structure (SC for short). On the premise of not increasing the plane size, radiation characteristic parameters are improved by loading a gradual groove correction Structure (SC). The improved Vivaldi antenna is called SCA for short.

The technical scheme adopted by the invention is as follows: slot correction Structure (SC) loading based on extended Vivaldi antenna studies. Loading a slot correction Structure (SC) on the basis of an EGSA antenna, and firstly proposing that the slot correction Structure (SC) consists of two rows with radius r ₀A circular slot configuration of 2mm, i.e. an exponentially graduated slot array. This structure can correct the phase distribution in the radiation section, which will be used for Vivaldi antennas to improve radiation efficiency. The phase difference can be corrected and compensated for in theory. The design is based on the theory of electromagnetic wave transmission because electromagnetic waves propagate faster in air than metals, thereby improving the radiation characteristics and directivity of certain frequencies within the bandwidth. The SCA antenna comprises a dielectric substrate, a metal radiating plate, a microstrip balun, an elliptical slot line, an index gradient slot and a slot correction Structure (SC). The metal radiating pieces are respectively fixed on the top surface and the bottom surface of the dielectric substrate, and the impedance matching microstrip balun is composed of a linear gradient microstrip line and a metal patch provided with an elliptical slot line. The metal radiating sheet is provided with a horn-shaped opening and an index gradual change groove line which is symmetrical about a horizontal central axis, the outer side wall of the metal radiating sheet is provided with a corrugated index gradual change groove, and a groove correction Structure (SC) is loaded at the index gradual change groove line of the EGSA.

Advantageous effects

The invention relates to a slot correction structure (tracking correction) loading based opposite-extension Vivaldi antenna research. Has the following beneficial effects:

(1) loading of the cell correction Structure (SC) at the exponentially graded radiation cell line of the EGSA is employed. Gain comparison of SCA with EGSA. The gains are similar in the range of 0.5-1.7 GHz. In the frequency range of 1.7-3.0GHz, the gain of SCA is improved more smoothly than that of EGSA. Compared with the EGSA which obtains a maximum value by obviously improving the position of 2.4GHz and a minimum value by obviously reducing the position of 2.6GHz, the SC structure with the increased SCA strengthens the current flowing along the slot line, and avoids the unstable improvement of the Vivaldi antenna when the frequency is increased.

(2) The loading of the SC structure strengthens the restraint of the exponential gradient slot line for radiation on the surface current, so that the SCA is more concentrated in the main radiation direction than the EGSA, and the end-fire performance is effectively improved. Meanwhile, the radiation patterns of the E surface and the H surface of the SCA are more symmetrical about the main radiation direction than that of the EGSA, and the fact that the current flows along the slot line symmetrical about the main radiation direction is guided by the SC structure near the slot line is proved to be beneficial to improving the radiation stability of the Vivaldi antenna.

(3) The structure is simple, the cost is low, the large-scale processing and production are convenient, and the device is suitable for ultrahigh frequency detection, communication and electronic countermeasure systems.

Drawings

FIG. 1 is a schematic structural diagram of an exponentially-graded slot Vivaldi antenna (EGSA) according to the present invention.

Fig. 2 is a schematic structural diagram of a Vivaldi antenna (SCA) loaded based on a slot calibration structure according to the present invention.

FIG. 3 is a comparison graph of return loss simulation results of EGSA and SCA.

FIG. 4 is a graph comparing the results of EGSA and SCA gain simulation.

Fig. 5 shows the radiation patterns of EGSA and SCA in the E-plane and H-plane at frequencies of 1.5, 2, 2.5,3 GHz.

Detailed Description

The invention is further described below with reference to the accompanying drawings and specific embodiments.

As shown in fig. 1EGSA and fig. 2GPA, the GPA provided by the present invention includes a dielectric substrate 1, a metal radiating plate 2, a microstrip balun 3, an elliptical slot line 4, an exponentially-graded slot line 5, a corrugated exponentially-graded slot (EGS)6, and a graded director plate (GP) 7. The metal radiating fins 2 are respectively fixed on the top surface and the bottom surface of the dielectric substrate 1, and the microstrip balun for impedance matching is composed of a linear gradient microstrip line and a metal patch provided with an elliptical slot line 4. The metal radiation sheet 2 is provided with an index gradual change groove line 5 which is provided with a horn-shaped opening and is symmetrical about the horizontal central axis, and the outer side wall of the metal radiation sheet 2 is provided with a corrugated index gradual change groove 6. The slot correction Structure (SC)7 is loaded at the exponentially graded radiation slot line. In this embodiment, the FR-4 dielectric board has a length of 99mm, a width of 99mm, a thickness of 2mm, a relative dielectric constant of 4.4, and a dielectric loss tangent of 0.02.

The expression of the two exponential transition slot lines 5 of the trumpet-shaped opening is as follows:

wherein, the curvature b and the starting point and the end point of the two exponential groove lines are determined as a, c, W ₀The width of the microstrip feed line is 50 omega. Ratio of major axis to minor axis of elliptical slot line is 0.107, L ₀The lateral distance from the focus of the ellipse to the edge of the dielectric plate.

The present embodiment loads the SC structure on the basis of EGSA with the structure of EGS (expression below).

To further constrain the surface current to flow along the slot lines. The SC structure is proposed for the first time, and two rows with radius r ₀A circular slot configuration of 2mm, i.e. an exponentially graduated slot array. This structure can correct the phase distribution in the radiation section, which will be used for Vivaldi antennas to improve radiation efficiency. The phase difference can be corrected and compensated for in theory. The design is based on the theory of electromagnetic wave transmission, since electromagnetic waves propagate faster in air than metals. Meanwhile, the current mobility of the slot line is increased, so that the radiation characteristics and the directivity of certain frequencies in the bandwidth are improved, the electromagnetic waves in the main radiation direction are more concentrated, and the end-fire performance is effectively improved.

After being optimized by HFSS software, the specific parameters of the GPA antenna are finally determined as shown in Table 1.

TABLE 1 antenna construction parameters

The embodiment is in an HFSS (electromagnetic simulation software)And carrying out modeling simulation. FIG. 3 is a diagram showing a comparison of return loss simulation results of GPA and EGSA, S ₁₁<The SCA and EGSA working frequency bands at-10 dB cover 0.77-3GHz, and the return loss of the SCA and the EGSA working frequency bands is similar;

fig. 4 shows the gain comparison between SCA and EGSA. The gains are similar in the range of 0.5-1.7 GHz. In the frequency range of 1.7-3.0GHz, the gain of SCA is improved more smoothly than that of EGSA. Compared with the EGSA with the maximum value obtained by obvious lifting at 2.4GHz and the minimum value obtained by obvious descending at 2.6GHz, the SC structure with the increased SCA strengthens the current flowing along the slot line. The unstable improvement of the Vivaldi antenna along with the increase of the frequency is avoided;

fig. 5 shows the E-plane and H-plane patterns of the EGSA and SCA antennas of the present embodiment at frequencies of 1.5, 2, 2.5, and 3 GHz. The sidelobes of SCA can be seen to be less than and less than EGSA while being more concentrated in the main radiation direction. Illustrating that loading of the SC enhances the confinement of the surface current to the exponentially graded slot line for radiation. Further, the electromagnetic wave in the main radiation direction is more concentrated, and the end-fire performance is effectively improved. Meanwhile, the radiation patterns of the E surface and the H surface of the SCA are more symmetrical about the main radiation direction than that of the EGSA, and the fact that the current flows along the slot line symmetrical about the main radiation direction is guided by the SC structure near the slot line is shown, and the stability of Vivaldi antenna radiation is improved.

Claims

1. The butt-extension Vivaldi antenna loaded based on the slot correction structure is characterized in that the slot correction structure is loaded on the basis of an EGSA antenna;

the SCA antenna comprises a dielectric substrate, a metal radiating plate, a microstrip balun, an elliptical slot line, an index gradient slot and a slot correction structure; the metal radiating pieces are respectively fixed on the top surface and the bottom surface of the dielectric substrate, and the impedance matching microstrip balun is composed of a linear gradient microstrip line and a metal patch provided with an elliptical slot line;

the metal radiating sheet is provided with a horn-shaped opening and an index gradual change groove line which is symmetrical about a horizontal central axis of the metal radiating sheet, the outer side wall of the metal radiating sheet is provided with a corrugated index gradual change groove, and a groove correction structure is loaded at the index gradual change groove line of the EGSA.

2. The pair-topology Vivaldi antenna loaded based on a slot-correction structure according to claim 1, characterized in that the slot-correction structure consists of two columns with radius r ₀A circular slot configuration of 2mm, i.e. an exponentially graduated slot array.

3. The pair-topology Vivaldi antenna based on slot correction structure loading of claim 1, wherein the expression of the two exponentially tapered slot lines is:

wherein, the curvature b and the starting point and the end point of the two exponential groove lines are determined as a, c, W ₀The width of the microstrip feed line is 50 omega, the ratio of the major axis and the minor axis of the elliptical slot line is 0.107, and L ₀The lateral distance from the focus of the ellipse to the edge of the dielectric plate.