Small-sized dual-polarization wide-beam low-cross-polarization ultra-wideband Vivaldi antenna

Abstract

The invention discloses a small-sized dual-polarization wide-beam low-cross-polarization ultra-wideband Vivaldi antenna, and belongs to the technical field of near-field test antennas. The antenna comprises a horizontal polarization Vivaldi antenna unit and a vertical polarization Vivaldi antenna unit, and the horizontal polarization Vivaldi antenna unit and the vertical polarization Vivaldi antenna unit are arranged on the upper surface of the floor through a grounding piece in a crisscross manner; each of the two parts comprises a mirror image comb-shaped structure, the mirror image comb-shaped structure comprises a left comb-shaped structure and a right comb-shaped structure which take the PCB open slot as a symmetry axis, and curve edges of the left comb-shaped structure and the right comb-shaped structure are close to each other to form a horn shape with a large upper opening and a small lower opening; each of the left comb-shaped structure and the right comb-shaped structure comprises a first tapered slot line plate and a second tapered slot line plate which are separately arranged up and down, and the first tapered slot line plate and the second tapered slot line plate are connected through a resistor. According to the invention, the structure size is reduced, the impedance bandwidth is improved, and cross polarization is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of near-field test antennas, and particularly relates to a small-sized dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna. Background Art

[0002] Probe antennas play an important role in test systems, especially in scenarios where plane waves need to be generated for accurate measurements. The gain of a single probe antenna is not high, and the beam width is not wide enough, making it difficult to generate a standard plane wave. However, in a probe antenna array, by applying appropriate excitation to each probe, a quasi-plane wave can be obtained in the near field, the antenna gain will be higher, there will be mutual coupling between the probes, and the beam width will also be wider.

[0003] Conventional probe antennas are large in size, which is not conducive to array formation. Moreover, they have single polarization, narrow beam width, narrow bandwidth, poor cross-polarization, etc., which will seriously affect the measurement distance and measurement accuracy. Therefore, it is necessary to design a small-sized dual-polarized wide-beam low cross-polarization ultra-wideband probe antenna to meet the design requirements of large probe array antennas. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a small-sized dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna, which can be applied in the field of probe antennas, especially in the field of large probe array antennas.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A small-sized dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna, comprising:

[0007] A horizontally polarized Vivaldi antenna unit and a vertically polarized Vivaldi antenna unit, which are arranged on the upper surface of the floor in a cross-shaped manner;

[0008] Both the horizontally polarized Vivaldi antenna unit and the vertically polarized Vivaldi antenna unit include a mirror image comb structure on a PCB substrate. The mirror image comb structure includes a left comb structure and a right comb structure that are symmetric about the PCB slot on the PCB substrate. The curved edges of the left comb structure and the right comb structure are close to each other to form a horn shape with a large upper opening and a small lower opening;

[0009] Both the left comb structure and the right comb structure include a first tapered slot line board and a second tapered slot line board that are arranged separately up and down. The first tapered slot line board and the second tapered slot line board are connected by a resistor.

[0010] Furthermore, the first tapered slot line board and the second tapered slot line board respectively include spaced rectangular slots with gradually increasing diameters.

[0011] Furthermore, the diameters of the spaced rectangular slots of the overall first and second tapered slot line plates increase sequentially from top to bottom.

[0012] Furthermore, it further includes an absorbing material, which surrounds the outer edge of the upper surface of the floor in a double-layer nested manner.

[0013] Furthermore, a first feeding balun and a second feeding balun are respectively arranged on the back of the PCB substrates where the horizontally polarized Vivaldi antenna unit and the vertically polarized Vivaldi antenna unit are located for coupled feeding.

[0014] Furthermore, the height of the second feeding balun is different from that of the first feeding balun.

[0015] Furthermore, the horizontally polarized Vivaldi antenna unit includes a first PCB slot at the central position of the first PCB substrate, and the vertically polarized Vivaldi antenna unit includes a second PCB slot at the central position of the second PCB substrate for realizing orthogonal insertion of the two PCB substrates.

[0016] Furthermore, the horizontally polarized Vivaldi antenna unit and the vertically polarized Vivaldi antenna unit are respectively connected to the floor through grounding tabs.

[0017] Furthermore, the horizontally polarized Vivaldi antenna unit and the vertically polarized Vivaldi antenna unit are respectively provided with rectangular resonant cavities.

[0018] Furthermore, the rectangular resonant cavities are located below the second tapered slot line plate and extend in the direction of the PCB slot line.

[0019] The beneficial effects of the present invention are as follows:

[0020] The present invention uses a tapered dressing structure to reduce the structural size and improve the impedance bandwidth; truncates the conventional Vivaldi antenna up and down and connects them with resistors, which is beneficial for low-frequency matching and improves the impedance bandwidth; adds an absorbing material to absorb reflected waves, improves the impedance bandwidth and reduces cross polarization. Description of the Drawings

[0021] Figure 1 It is a 3D structure diagram of a small dual-polarized wide-beam low-cross-polarization ultra-wideband Vivaldi antenna according to the present invention;

[0022] Figure 2 It is a top view and a bottom view of the horizontally polarized Vivaldi antenna unit according to the present invention;

[0023] Figure 3 It is a top view and a bottom view of the vertically polarized Vivaldi antenna unit according to the present invention;

[0024] Figure 4 Schematic diagram of S parameters of a small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to the present invention;

[0025] Figure 5 Horizontal pattern at 200 MHz of a small verticalized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to the present invention;

[0026] Figure 6 Horizontal pattern at 400 MHz of a small verticalized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to the present invention;

[0027] Figure 7 Horizontal pattern at 600 MHz of a small verticalized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to the present invention.

[0028] Reference numerals:

[0029] Horizontal polarization Vivaldi antenna element 1, vertical polarization Vivaldi antenna element 2, absorbing material 3, floor 4, ground sheet 5, first tapered slot line board 11, second tapered slot line board 12, first PCB substrate 13, resonant cavity 14, RF connector 16, resistor 17, first feeding balun 18, first comb structure 111, second comb structure 121, first PCB slot 131, second PCB substrate 23, second PCB slot 231, second feeding balun 28. Detailed implementation manners

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] As Figure 1 shown, the present invention provides a small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna, including a horizontal polarization Vivaldi antenna element 1, a vertical polarization Vivaldi antenna element 2, an absorbing material 3, a floor 4, and a ground sheet 5. Among them, the horizontal polarization Vivaldi antenna element 1 and the vertical polarization Vivaldi antenna element 2 are arranged on the upper surface of the floor 4 in a cross-cross manner through the ground sheet 5, and the absorbing material 3 surrounds the outer edge of the upper surface of the floor 4 in a double-layer nested manner. Among them, the structures of the horizontal polarization Vivaldi antenna element 1 and the vertical polarization Vivaldi antenna element 2 are completely the same. The following takes the horizontal polarization Vivaldi antenna element 1 as an example for a specific structural introduction.

[0032] As Figure 2As shown, the horizontally polarized Vivaldi antenna unit 1 includes a first PCB substrate 13 and a mirror comb structure stacked in sequence from bottom to top. Among them, the mirror comb structure includes a left comb structure and a right comb structure symmetric about the first PCB slot 131. The curved edges of the left comb structure and the right comb structure are close to each other to form a horn shape, with a small opening at the lower end and a large opening at the upper end. The first PCB slot 131 is located at the central position of the lower end of the first PCB substrate 13, facilitating the orthogonal insertion of the two PCB substrates corresponding to the horizontally polarized Vivaldi antenna unit 1 and the vertically polarized Vivaldi antenna unit 2. Since the left comb structure and the right comb structure are mirror-symmetric structures, the specific structure of the left comb structure is introduced as an example.

[0033] The left comb structure includes a first tapered slot line board 11 and a second tapered slot line board 12 arranged separately up and down and connected by a welded resistor 17. Among them, the first tapered slot line board 11 includes a first comb structure 111, and the first comb structure 111 is an interval rectangular slot with a gradually increasing diameter. The second tapered slot line board 12 includes a second comb structure 121, and the second comb structure 121 is also an interval rectangular slot with a gradually increasing diameter. The first comb structure 111 and the second comb structure 121 together form a tapered comb structure, which can increase the current path, reduce the structural size, provide multiple resonance paths, and improve the impedance bandwidth. Preferably, the diameters of the interval rectangular slots increase sequentially from the first comb structure 111 to the second comb structure 121.

[0034] The horizontally polarized Vivaldi antenna unit 1 is provided with a large rectangular resonant cavity 14, which can extend the grounding path and reduce the size. The rectangular resonant cavity 14 is realized by symmetrically digging rectangular slots at the lower ends of the left comb structure and the right comb structure, which is beneficial to low-frequency impedance matching, improves the impedance bandwidth, reduces the size, and the rectangular slot has a preset interval from the second comb structure 121.

[0035] The ground plate 5 is welded to the left comb structure and the right comb structure of the mirror comb structure respectively and locked on the floor 4 with screws to form a good ground. The first feeding balun 18 is located on the back of the first PCB substrate 13, and the Vivaldi antenna is coupled and fed by using the first feeding balun 18. The input end of the first feeding balun 18 is welded to the RF connector 16, and the RF connector 16 is connected to the left or right comb structure.

[0036] As Figure 3As shown in the figure, on the second PCB substrate 23 of the vertically polarized Vivaldi antenna element 2, a second PCB slot 231 is provided to facilitate the orthogonal insertion of the two PCB substrates corresponding to the horizontally polarized Vivaldi antenna element 1 and the vertically polarized Vivaldi antenna element 2. A second feed balun 28 is provided on the back. The second feed balun 28 is slightly 4 mm lower in height than the first feed balun 18 to avoid overlap. All other structural dimensions are the same as those of the horizontally polarized Vivaldi antenna element 1.

[0037] The antenna of the present invention is very small in size. The antenna width is about 0.16λ0 (conventional size is greater than 0.5λ0), and the antenna height is about 0.25λ0 (conventional size is greater than λ0), where λ0 is the corresponding low-frequency operating wavelength. Due to the very small antenna size, the low-frequency impedance is very small and the inductance effect is strong. The conventional Vivaldi antenna is divided into upper and lower parts and connected by a resistor to increase the low-frequency impedance, reduce the inductance effect, facilitate impedance matching, and expand the impedance bandwidth. Absorbing materials are added to absorb the reflected waves, which not only facilitates impedance matching but also improves the cross-polarization level and generates better plane waves.

[0038] As Figure 4 shown, the S-parameters of the small dual-polarized wide-beam low-cross-polarization ultra-wideband Vivaldi antenna are such that the reflection coefficients of the two polarizations are less than -10 dB within the wide frequency band of 200 MHz to 600 MHz, and the isolation degree of the two polarizations is very good, lower than -42 dB.

[0039] As Figures 5 - 7 shown, the horizontal pattern of the vertically polarized small dual-polarized wide-beam low-cross-polarization ultra-wideband Vivaldi antenna is such that the antenna has a stable and wide pattern (beam width greater than 80°) within the wide frequency band and low cross-polarization (less than -25 dB), and can be applied in the field of array probe antennas.

[0040] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A small-sized dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna, characterized in that, Comprising: A horizontally polarized Vivaldi antenna element and a vertically polarized Vivaldi antenna element, which are arranged on the upper surface of the floor in a cross-cross manner; Both the horizontally polarized Vivaldi antenna element and the vertically polarized Vivaldi antenna element include a mirror comb structure on a PCB substrate. The mirror comb structure includes a left comb structure and a right comb structure that are symmetric about the PCB slot on the PCB substrate. The curved sides of the left comb structure and the right comb structure are close to each other to form a horn shape with a large upper opening and a small lower opening; Both the left comb structure and the right comb structure include a first tapered slot line board and a second tapered slot line board that are arranged separately up and down. The first tapered slot line board and the second tapered slot line board are connected by a resistor.

2. A small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to claim 1, characterized in that The first tapered slot line board and the second tapered slot line board respectively include spaced rectangular slots with gradually increasing diameters.

3. A small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to claim 2, characterized in that, The spaced rectangular slots of the first tapered slot line board and the second tapered slot line board as a whole increase in diameter from top to bottom in sequence.

4. A small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to claim 1, characterized in that, It also includes an absorbing material, and the absorbing material surrounds the outer edge of the upper surface of the floor in a double-layer nested manner.

5. A small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to claim 1, characterized in that A first feeding balun and a second feeding balun are respectively arranged on the back of the PCB substrates where the horizontally polarized Vivaldi antenna element and the vertically polarized Vivaldi antenna element are located for coupled feeding.

6. A small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to claim 3, characterized in that, The height of the second feeding balun is different from that of the first feeding balun.

7. A small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to claim 1, characterized in that, The horizontally polarized Vivaldi antenna element includes a first PCB slot at the central position of the first PCB substrate, and the vertically polarized Vivaldi antenna element includes a second PCB slot at the central position of the second PCB substrate for realizing orthogonal insertion of the two PCB substrates.

8. A small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to claim 1, characterized in that, The horizontally polarized Vivaldi antenna element and the vertically polarized Vivaldi antenna element are respectively connected to the floor through grounding tabs.

9. A small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to claim 1, characterized in that, The horizontally polarized Vivaldi antenna element and the vertically polarized Vivaldi antenna element are respectively provided with rectangular resonant cavities.

10. A small dual-polarized wide-beam low cross-polarization ultra-wideband Vivaldi antenna according to claim 9, characterized in that, The rectangular resonant cavity is located below the second tapered slot line board and extends in the direction of the PCB slot line.

Images