A Vivaldi antenna

Abstract

The present disclosure provides a Vivaldi antenna, which includes two symmetrically arranged radiation units. Each radiation unit includes a slot line forming an opening; a resonant cavity connected to the slot line; a truncated boundary unit disposed between the slot lines of the two radiation units and extending axially; and a feeding unit. By arranging the truncated boundary unit between the slot lines of the Vivaldi antenna, stable gain and beam width are achieved within a wideband.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and in particular, to a Vivaldi antenna. Background Art

[0002] An antenna is an essential device for transmitting and receiving electromagnetic waves in wireless communication, and the performance of the antenna determines the efficiency of electromagnetic energy transmission. With the rapid development of communication technologies, people have put forward higher and higher requirements for the performance of antennas. For example, in some scenarios of wireless communication or wireless testing, it is required that the antenna can have a stable wide beam within a relatively wide frequency band. Summary of the Invention

[0003] The present disclosure describes a Vivaldi antenna.

[0004] According to a first aspect of an embodiment of the present disclosure, there is provided a Vivaldi antenna, including: two symmetrically arranged radiation units, each radiation unit including a slot line forming an opening; a resonant cavity connected to the slot line; a truncated boundary unit disposed between the slot lines of the two radiation units and extending axially; and a feeding unit.

[0005] According to an embodiment of the Vivaldi antenna, one end of the truncated boundary unit away from the resonant cavity is the distal end, the opening formed by the slot line at the distal end is the minimum physical aperture of the Vivaldi antenna, and the ratio of the maximum size of the minimum physical aperture of the Vivaldi antenna to the wavelength corresponding to the highest operating frequency of the Vivaldi antenna is a first ratio R1, and R1 satisfies the following range: 1 / 4 ≤ R1 ≤ 2; the ratio of the maximum size of the maximum physical aperture of the Vivaldi antenna to the wavelength corresponding to the lowest operating frequency of the Vivaldi antenna is a second ratio R2, and R2 satisfies the following range: 1 / 4 ≤ R2 ≤ 2.

[0006] According to an embodiment of the Vivaldi antenna, R1 satisfies the following range: 1 / 2 ≤ R1 ≤ 1; R2 satisfies the following range: 1 / 2 ≤ R2 ≤ 1.

[0007] According to an embodiment of the Vivaldi antenna, R1 is equal to R2.

[0008] According to an embodiment of the Vivaldi antenna, the radiation unit further includes an arc line smoothly connected to the slot line, the arc line extends in the direction where the opening of the slot line becomes narrower, and the maximum opening formed by the arc line is the maximum physical aperture of the Vivaldi antenna.

[0009] According to an embodiment of the Vivaldi antenna, one end of the truncated boundary unit is connected to the resonant cavity.

[0010] According to an embodiment of the Vivaldi antenna, the feeding unit adopts differential feeding.

[0011] According to an embodiment of the Vivaldi antenna, the Vivaldi antenna is disposed on a dielectric substrate, the dielectric substrate includes at least three metal layers, and the feeding unit is disposed on the middle metal layer.

[0012] According to the second aspect of the embodiments of the present disclosure, a dual-polarized antenna is provided, including two aforementioned Vivaldi antennas.

[0013] According to the third aspect of the embodiments of the present disclosure, a circularly polarized antenna is provided, including two aforementioned Vivaldi antennas.

[0014] In the embodiments of the present disclosure, by disposing a truncation boundary unit between the slot lines of the Vivaldi antenna, the difference in electrical aperture between different frequency bands during broadband use of the Vivaldi antenna is reduced, thereby achieving stable gain and beam width within the broadband. Description of the Drawings

[0015] Figure 1 is a schematic diagram of a Vivaldi antenna in the related art.

[0016] Figure 2 is a schematic diagram of the Vivaldi antenna shown according to an embodiment of the present disclosure.

[0017] Figure 3 is a schematic diagram of the Vivaldi antenna shown according to an embodiment of the present disclosure.

[0018] Figure 4 is a schematic diagram of the Vivaldi antenna shown according to an embodiment of the present disclosure. Detailed Embodiments

[0019] The embodiments of the present disclosure are described below with reference to the drawings. It should be understood that the drawings are not necessarily to scale. The described embodiments are exemplary and are not intended to limit the present disclosure, and the features of the embodiments can be combined or substituted with these features in the same or similar manner. The singular forms "a", "the" and "said" used in the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0020] A wireless communication device transmits and receives electromagnetic waves through an antenna, and the wireless transceiver performance of the communication device is often evaluated by testing the antenna. In some scenarios of wireless communication or wireless testing, it is required that the antenna can have a stable wide beam within a relatively wide frequency band.

[0021] The Vivaldi antenna is a planar-structured antenna. Its radiation structure consists of slot lines that gradually open. It has excellent radiation characteristics and a relatively wide operating frequency band, and is widely used in fields such as wireless communication systems, phased array radars, and radio astronomy. Refer to Figure 1 , Figure 1 which schematically shows a typical Vivaldi antenna in the related art.

[0022] In the related art, the radiation (transmission or reception) state of an antenna can be characterized to a certain extent by the antenna aperture, including several different characterization methods: physical aperture, which is the mechanical size of the antenna radiation aperture; effective aperture, which can be obtained through calculation or measurement; effective height, which is obtained by multiplying the physical height or length of a wire antenna by the (normalized) average current; electrical aperture, whose calculation method is the ratio of the maximum size of the physical aperture to the wavelength of a specific frequency. It can be understood that the radiation characteristics of the antenna at this frequency are related to the size of the electrical aperture. Specifically, the size of the electrical aperture is positively correlated with the antenna gain and negatively correlated with the size of the beam width. In the Figure 1 Vivaldi antenna shown, the physical aperture of the electromagnetic wave radiation is the widest part L0 of the slot line opening, and the electromagnetic waves at different frequencies share this physical aperture L0. For an antenna, at the same physical aperture, when the frequency of the electromagnetic wave is higher and the wavelength is shorter, the electrical aperture of the antenna is larger, that is, the antenna gain is higher and the beam width is smaller; conversely, when the frequency of the electromagnetic wave is lower and the wavelength is longer, the electrical aperture of the antenna is smaller, that is, the antenna gain is lower and the beam width is larger. Taking the Figure 1 Vivaldi antenna shown as an example, assuming that the lowest operating frequency of this antenna is 1 GHz. In the related art, the Vivaldi antenna is usually designed such that its electrical aperture satisfies half of the wavelength of the lowest frequency, that is, Figure 1 for the Vivaldi antenna shown, the electrical aperture at 1 GHz is 1 / 2 times the wavelength corresponding to 1 GHz. According to the calculation method of the electrical aperture, the maximum size of its physical aperture (i.e., the widest part L0 of the slot line opening) can be calculated to be 1 / 2 times the wavelength corresponding to 1 GHz. Then, it can be calculated that its electrical aperture at 2 GHz is 1 time the wavelength corresponding to 2 GHz. That is to say, it has different electrical apertures at different frequency bands. When the Vivaldi antenna is used for an ultra-wide frequency band, due to the different electrical apertures at different frequencies, there may be large differences in the gain and beam width within the wide frequency band, which will limit its application. For example, in some usage scenarios of wireless measurement, it is required that the antenna maintains a stable beam width within the wide frequency band.

[0023] In view of this, an embodiment of one aspect of the present disclosure provides a Vivaldi antenna. Refer to Figure 2, the Vivaldi antenna includes two symmetrically arranged radiation units 100. Each radiation unit 100 includes a slot line 101, which can be, for example, an exponentially tapered shape. The two slot lines 101 form an opening for radiation; a resonant cavity 200, which is connected to the slot line 101; a truncated boundary unit 300, which is arranged between the slot lines 101 of the two radiation units 100 and extends axially. Here, the "axis" can be understood as the axis of symmetry of the two slot lines 101; and a feeding unit (not shown in the figure). The setting of the truncated boundary unit 300 causes the physical aperture of the Vivaldi antenna at high frequencies to move down from Figure 1 the L0 shown to Figure 2 the L1 shown, which is equivalent to reducing the electrical aperture at high frequencies, thereby reducing the difference in electrical apertures between different frequency bands within the broadband range, and thus achieving relatively stable gain and beam width within the broadband.

[0024] Here, the electrical apertures of electromagnetic waves with different frequencies in the Vivaldi antenna of this embodiment will be described. Referring to Figure 2 , the end of the truncated boundary unit 300 far from the resonant cavity 200 is the distal end 301. The opening L1 formed by the slot line 101 at the distal end 301 is the minimum physical aperture, and the electrical aperture of the Vivaldi antenna at high frequencies is the ratio of the maximum size of this minimum physical aperture to the wavelength corresponding to the highest operating frequency of the Vivaldi antenna, which is defined here as the first ratio R1. On the other hand, the widest part L2 of the opening of the slot line 101 is the maximum physical aperture, and the electrical aperture of the Vivaldi antenna at low frequencies is the ratio of the maximum size of this maximum physical aperture to the wavelength corresponding to the lowest operating frequency of the Vivaldi antenna, which is defined here as the second ratio R2. It can be understood that for the Vivaldi antenna, the maximum size of the minimum physical aperture can be considered as the distance between the two slot lines 101 at the opening L1, and the maximum size of the maximum physical aperture can be considered as the distance between the two slot lines 101 at the opening L2.

[0025] Optionally, in some embodiments, the first ratio R1 (i.e., the electrical aperture at high frequency) and the second ratio R2 (i.e., the electrical aperture at low frequency) respectively satisfy the following ranges: 1 / 4 ≤ R1 ≤ 2; 1 / 4 ≤ R2 ≤ 2. This limits the difference in the electrical aperture of the Vivaldi antenna within a certain range over a relatively wide operating frequency band. Further, in some embodiments, the above-mentioned first ratio R1 and second ratio R2 are defined as: 1 / 2 ≤ R1 ≤ 1; 1 / 2 ≤ R2 ≤ 1. Even further, in some embodiments, the first ratio R1 is equal to the second ratio R2. It should be noted that in order to obtain a stable beam within a wide frequency band, the electrical apertures of the antenna at different frequency bands should be as close as possible. In theory, the closer the first ratio R1 and the second ratio R2 are, the smaller the difference in the electrical aperture between different frequency bands of the antenna. However, in practice, the beam width is also affected by other factors, such as the dielectric constant of the antenna PCB board (for PCB board antennas), the environment around the antenna (such as absorbing materials, common-mode currents on the feeder cables, antenna mechanical structural members), etc. These effects may cause the electrical apertures not to be equal even when the first ratio R1 and the second ratio R2 are equal. Therefore, the first ratio R1 and the second ratio R2 can be adjusted according to the antenna accuracy requirements and the influence of the above factors.

[0026] Optionally, in some embodiments, referring to Figure 3 , the radiation unit 100 further includes an arc line 102 that is smoothly connected to the slot line 101. The arc line 102 extends in the direction in which the opening of the slot line 101 becomes narrower (in Figure 3 , the direction in which the opening of the slot line 101 becomes narrower is downward), and the maximum opening L2' formed by the arc line 102 is the maximum physical aperture. The added arc line 102 increases the current path. Compared with the radiation unit structure in Figure 2 , a larger physical aperture can be achieved with a smaller antenna size to achieve a lower operating frequency.

[0027] It should be noted that in this embodiment, the specific shape of the truncated boundary unit is not limited and can be designed according to specific feeding requirements and beam requirements. For example, it can include a shape with a gradually changing width. In addition, one end of the truncated boundary unit close to the resonant cavity can extend downward into the resonant cavity and can be further connected to the resonant cavity. Referring to Figure 4 , one end 302 of the truncated boundary unit 300 close to the resonant cavity 200 extends downward into the resonant cavity 200 and is connected to the resonant cavity 200 as a whole. In this case, the structure is equivalent to forming two resonant cavities 200. It can be understood that the position of one end of the truncated boundary close to the resonant cavity is related to the feeding position of the antenna, and it is necessary to ensure that the current can propagate along the truncated boundary unit after flowing out from the feeding point.

[0028] In some embodiments, the feeding unit of the Vivaldi antenna adopts differential feeding, that is, the current phases of the two feeding units differ by 180°, so as to obtain a better radiation pattern.

[0029] In some embodiments, the Vivaldi antenna is disposed on a dielectric substrate. The dielectric substrate includes at least three metal layers. The feeding unit is disposed on the middle metal layer to form shielded feeding. The radiation units are located on other metals outside the feeding metal layer. The two radiation units can be on the same metal layer or on different metal layers.

[0030] Another embodiment of the present disclosure provides a dual-polarized antenna, which includes two Vivaldi antennas as described above.

[0031] Another embodiment of the present disclosure provides a circularly polarized antenna, which includes two Vivaldi antennas as described above, and circular polarization can be achieved through a 3dB bridge.

[0032] It should be noted that the figures in the present disclosure are all simplified schematic diagrams, which are only used to schematically illustrate the positional relationship and connection relationship between the various parts in the embodiments. The antennas of the present disclosure may also include other conventional structures, such as components or matrix materials for fixing or supporting.

[0033] In the above description, the descriptions with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one implementation or example of the present disclosure. In the present disclosure, the schematic expressions of the above terms do not necessarily refer to the same implementation or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more implementations or examples.

[0034] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present disclosure, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0035] Although the embodiments of the present disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A Vivaldi antenna, characterized in that, Comprising: Two symmetrically arranged radiation units, each of the radiation units including a slot line forming an opening; A resonant cavity, the resonant cavity being connected to the slot line; A truncated boundary unit, the truncated boundary unit being arranged between the slot lines of the two radiation units and extending axially; wherein, the arrangement of the truncated boundary unit moves the position of the physical aperture of the Vivaldi antenna at high frequencies downward, for reducing the difference between the electrical aperture at high frequencies and the electrical aperture at low frequencies; the electrical aperture of the Vivaldi antenna at high frequencies means that the ratio of the maximum dimension of the minimum physical aperture of the Vivaldi antenna to the wavelength corresponding to the highest operating frequency of the Vivaldi antenna is a first ratio R1, and the R1 satisfies the following range: 1 / 4 ≤ R1 ≤ 2; the end of the truncated boundary unit away from the resonant cavity is the distal end, and the opening formed by the slot line at the distal end is the minimum physical aperture of the Vivaldi antenna; the electrical aperture of the Vivaldi antenna at low frequencies means that the ratio of the maximum dimension of the maximum physical aperture of the Vivaldi antenna to the wavelength corresponding to the lowest operating frequency of the Vivaldi antenna is a second ratio R2, and the R2 satisfies the following range: 1 / 4 ≤ R2 ≤ 2; And a feeding unit.

2. The Vivaldi antenna according to claim 1, characterized in that, The R1 satisfies the following range: 1 / 2 ≤ R1 ≤ 1; the R2 satisfies the following range: 1 / 2 ≤ R2 ≤ 1.

3. The Vivaldi antenna according to claim 1, characterized in that, The R1 is equal to the R2.

4. The Vivaldi antenna according to claim 1, characterized in that, The radiation unit further includes an arc line smoothly connected to the slot line, the arc line extending in the direction where the opening of the slot line becomes narrower, and the maximum opening formed by the arc line is the maximum physical aperture of the Vivaldi antenna.

5. The Vivaldi antenna according to claim 1, characterized in that, One end of the truncated boundary unit is connected to the resonant cavity.

6. The Vivaldi antenna according to claim 1, characterized in that, The feeding unit adopts differential feeding.

7. The Vivaldi antenna according to claim 1, characterized in that, The Vivaldi antenna is arranged on a dielectric substrate, the dielectric substrate includes at least three metal layers, and the feeding unit is arranged on the middle metal layer.

8. A dual-polarized antenna, characterized in that, Comprising two Vivaldi antennas according to any one of claims 1-7.

9. A circularly polarized antenna, characterized in that, Comprising two Vivaldi antennas according to any one of claims 1-7.

Images