A broadband dual-channel transflective receiving antenna

Abstract

The present invention discloses a dual-channel transflective receiving antenna operating in the X and Ku bands. The dual-channel transflective receiving antenna provided by the present invention comprises a Vivaldi antenna, a broadband horn antenna and a transflective array of a four-layer dielectric plate. The four-layer transflective array is composed of broadband transflective dual-channel units. The four-layer transflective array can effectively convert the spherical waves emitted by the Vivaldi antenna and the horn antenna respectively located on both sides of the array into high-gain beams emitted in the z direction in the X and Ku bands, that is, it can realize the spatial separation and focusing of the x and y polarized electromagnetic waves incident in the z direction, and then independently receive them through the Vivaldi antenna and the horn antenna respectively.

Description

Technical Field

[0001] The invention belongs to the field of antennas, and in particular relates to a broadband dual-channel antenna for separating transmission and reflection of orthogonal linear polarization incoming waves and then independently receiving them. Background Art

[0002] Reflectarray antennas combine the advantages of array antennas and parabolic reflector antennas. They have a planar structure that can form high-gain beams, and do not require a complex feeding network. Therefore, they have the advantages of low profile, foldability, and low cost. Reflectarray antennas have always attracted the interest of researchers, and research results on reflectarray antennas have been continuously reported. Transmission array antennas also have the characteristics of low profile and low cost. Unlike reflectarray antennas, they modulate the phase or amplitude of electromagnetic waves at the transmission end to manipulate electromagnetic waves, such as high-gain beam generation, beam deflection, and beam shaping. Compared with reflectarray antennas, the biggest difficulty in the design of transmission array antennas is how to ensure the transmission efficiency. Compared with reflectarray antennas, their biggest advantage is that they isolate the space between the feed source and the beam modulation, avoiding mutual interference between the feed source and the beam. In practice, however, reflective array antennas and transmission array antennas often cannot switch between each other, that is, the transmission array cannot modulate and manipulate electromagnetic waves at the reflection end, and the reflective array cannot modulate and manipulate electromagnetic waves at the transmission end. If the integration of the transflective antenna functions of the same array can be achieved, the utilization efficiency of the aperture and space will be greatly improved, and it will have good application prospects in engineering.

[0003] On the other hand, whether for reflective array antennas or transmission array antennas, the multifunctional reuse of the same array is a research hotspot and a direction that antenna designers are constantly exploring. Specific forms of multifunctional reuse include frequency reuse, polarization reuse, and space-time reuse. Among these forms of reuse, polarization reuse is the most basic form of reuse, because any polarization form of electromagnetic waves can be generated by superposition of a pair of orthogonal polarization waves. If the same antenna array can have completely independent and designable functions for a pair of orthogonal polarization waves, it can not only greatly improve the utilization efficiency of its aperture, but also achieve independent dual-channel information transmission.

[0004] In summary, transflective array switching and polarization multiplexing are the research difficulties and hotspots of antenna arrays, and have important engineering application significance. If the two can be combined to realize polarization multiplexing at the transflective end, that is, orthogonal polarized waves realize transmission modulation and reflection modulation respectively, it will be of great significance, because orthogonally polarized electromagnetic waves can carry independent communication information, separate them to both sides of the array, and then independently modulate or receive them, which can not only realize the transmission or reception of dual-channel independent information, but also realize the absolute separation of information and avoid interference between them. The realization of this polarization-multiplexed transflective independent transmitting or receiving antenna requires not only an array that can switch the transflective function for orthogonal polarized waves, but also a broadband antenna as a receiving terminal. The Vivaldi antenna is a small-sized antenna excited by a slot line. It is generally radiated through a coaxial feeding and then a microstrip line to slot line structure. Although its matching performance is average, it can achieve broadband radiation, and due to its small size, the beam shielding can be approximately ignored. Therefore, the Vivaldi antenna is suitable as a transmitting or receiving terminal at the reflective end. As for the transmitting or receiving terminal at the transmission end, since there is no shielding problem, a general broadband horn antenna can be used as the feed source or receiving terminal at the transmission end. Summary of the invention

[0005] The purpose of the present invention is to achieve the transflective spatial separation and independent reception of the x and y polarization components of the normally incident electromagnetic wave by designing a polarization multiplexing transflective array working in the X and Ku bands, and combining a Vivaldi antenna and a horn antenna as a receiving terminal (feed source).

[0006] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a transflective array working in the X and Ku bands is designed, which can efficiently co-polarize the x-polarized wave incident along the -z direction, and efficiently polarize the y-polarized wave incident along the -z direction, and can perform 3-bit phase control respectively, and these two 3-bit phase controls are relatively independent and have little influence on each other. By designing the transflective phase distribution of the array for the incident x-polarized wave and the y-polarized wave, a Vivaldi antenna is combined to receive the co-polarized reflected wave of the x-polarized incident wave on the +z side, and a broadband horn antenna is used to receive the polarized transmitted wave of the y-polarized incident wave on the -z side, thereby realizing a broadband dual-channel transflective receiving antenna.

[0007] The Vivaldi antenna adopts a microstrip line to slot line structure, which can effectively radiate spherical waves in the X and Ku bands. The broadband horn antenna adopts coaxial excitation and waveguide to horn mouth radiation, which can effectively radiate spherical waves in the X and Ku bands.

[0008] The transflective array is composed of 25*25 transflective antenna units working in the X and Ku bands. The dual-channel transflective unit is composed of four dielectric plates and five metal layers, wherein the third and fifth layers are orthogonal metal gratings, the first and second layers are x-polarized incident wave co-polarized reflection phase modulation layers, and the fourth layer is y-polarized incident wave polarization conversion transmission phase modulation layer.

[0009] The unit structure of the transflective array has a metal strip length of the first metal layer that is 0.75 times the length of the metal strip length of the second metal layer. By adjusting the length of the second metal strip, and the adjustment range is 4.7mm-8.2mm, 3-bit modulation of the co-polarized reflection phase of the x-polarized incident wave can be achieved. For the fourth metal layer, by designing four polarization conversion metal structures and obtaining another four metal structures by mirroring operation, 3-bit modulation of the polarization conversion transmission phase of the y-polarized incident wave can be achieved. The third and fifth metal layers are orthogonal metal gratings and are fixed.

[0010] The method for setting up the broadband dual-channel transflective receiving antenna is as follows: the x-polarized Vivaldi antenna is located on the +z side of the transflective array, the x-polarized broadband horn antenna is located on the -z side of the transflective array, and the geometric centers of the Vivaldi antenna, the horn antenna and the transflective array are located on a straight line parallel to the z-axis. The x-polarized spherical waves emitted by the Vivaldi antenna in the X and Ku bands are reflected by the transflective array as x-polarized high-gain beams emitted in the +z direction. The x-polarized spherical waves emitted by the horn antenna in the X and Ku bands are transmitted by the transflective array as y-polarized high-gain beams emitted in the +z direction. According to the reversible principle of the optical path, the receiving antenna can also realize the dual-channel transflective spatial separation and independent reception of x-polarized and y-polarized electromagnetic waves incident in the -z direction of the same band.

[0011] The advantages of the present invention are:

[0012] 1. When the dual-channel transflective receiving antenna works in reflection mode, it can achieve an antenna gain of more than 20dB in the frequency range of 10.5-16.5GHz. The polarization mode is x-polarization. The peak gain reaches 27dB at 12GHz, the peak aperture efficiency is 40%, and the 3dB gain bandwidth is 11-16GHz.

[0013] 2. When the dual-channel transflective receiving antenna works in the transmission mode, it can achieve an antenna gain of more than 20dB in the frequency range of 9-18GHz. The polarization mode is y-polarization, and the peak gain reaches 28dB at 14GHz, the peak aperture efficiency is 39%, and the 3dB gain bandwidth is 11.5-17GHz.

[0014] 3. The use of Vivaldi antennas effectively reduces obstruction and has no significant impact on the formation of reflected and transmitted high-gain beams. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0016] Figure 1 It is the overall structure diagram of the dual-channel transflective receiving antenna, structure 10 is an x-polarized Vivaldi antenna, structure 20 is an x-polarized broadband horn antenna, and structure 30 is a transflective array of four-layer dielectric plates operating in the X and Ku bands.

[0017] Figure 2 The structure 30 is a four-layer transflective array operating in the X and Ku bands, which is composed of 25*25 transflective units.

[0018] Figure 3 Schematic diagram of the structure of the unit constituting the transflective array, which is composed of 4 layers of dielectric substrate and 5 layers of metal layer, wherein the dielectric constant of the dielectric plate is equal to 2.65, the thickness d1=d2=1mm, d3=d4=2mm, and the unit period p=10mm.

[0019] Figure 4 Schematic diagram of the structure of the metal layer constituting the transflective unit, 4(a) is the top metal layer, 4(b) is the second metal layer, 4(c) is the third metal layer, and 4(d) is the fifth metal layer. The length of the metal strip in 4(a) is 0.75 times the length of the metal strip in 4(b). 4(e)-4(l) are eight specific structures of the fourth metal layer, and their specific parameters are w1=1mm, l1=3.6mm, l2=9.9mm, g1=0.3mm, w2=0.5mm, r1=4.5mm, α1=12°, w3=0.7mm, α2=42°, r2=4.5mm, g2=1.2mm, w4=0.5mm.

[0020] Figure 5 By changing l x The schematic diagram of the structure of the fourth metal layer realizes the three-bit phase modulation of the x-polarized wave co-polarization reflection and the y-polarized wave polarization conversion transmission. xWhen the lengths are 4.7mm, 5.2mm, 5.6mm, 6mm, 6.5mm, 7.2mm, 7.8mm, and 8.2mm, as shown in 5(a), the co-polarization reflection amplitude of the x-polarized wave is above 0.8 in the entire X and Ku bands, and as shown in 5(b), the co-polarization reflection phase of the x-polarized wave achieves 3-bit modulation near 13GHz, and the curve has good parallelism in the broadband range. On the other hand, when the fourth metal layer takes the eight structures of 000-111 shown in 4(e)-4(l), as shown in 5(c), the polarization transmission amplitude of the y-polarized wave is kept above 0.7 in most frequency bands of the X and Ku bands, and as shown in 5(d), the polarization transmission phase of the y-polarized wave achieves 3-bit modulation near 13GHz, and the curve has very good parallelism in most frequency bands of the X and Ku bands.

[0021] Figure 6 Schematic diagram to prove the independence between the three-bit phase modulation of transmission and reflection. x =6.5mm and the fourth metal structure is 000-111, the change of the co-polarization reflection phase and co-polarization reflection amplitude of the x-polarized wave. 6(b) is the change of the co-polarization reflection phase and co-polarization reflection amplitude of the x-polarized wave when the fourth metal structure is 101 and l x Schematic diagram of the change of y-polarized wave polarization transmission phase and polarization transmission amplitude when taking 8 kinds of 3-bit parameters from 4.7mm to 8.2mm.

[0022] Figure 7 In the figure, 7(a) is the designed 3-bit compensatory phase distribution for the co-polarized reflection of the x-polarized incident wave incident on the array for the 10-structure excitation, and 7(b) is the designed 3-bit compensatory phase distribution for the polarization-transferred transmission of the x-polarized incident wave incident on the array for the 20-structure excitation.

[0023] Figure 8 In the figure, 8(a) is the three-dimensional far-field distribution diagram at a frequency of 13 GHz formed by the x-polarized wave excited by the 10 structures incident on the array, and 8(b) is the three-dimensional far-field distribution diagram at a frequency of 13 GHz formed by the x-polarized wave excited by the 20 structures incident on the array.

[0024] Fig. 9 In the figure, 9(a) shows the gain along the normal reflection and the corresponding aperture efficiency achieved in a broadband range when the 10 structure excites the x-polarized incident wave. 9(b) shows the gain along the normal transmission and the corresponding aperture efficiency achieved in a broadband range when the 20 structure excites the x-polarized incident wave. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation plans.

[0026] like Figure 1 As shown, the designed broadband dual-channel transflective receiving antenna is composed of the Vivaldi antenna shown in structure 10, the broadband horn antenna shown in structure 20, and the transflective array shown in structure 30. The polarization modes of the Vivaldi antenna and the broadband horn antenna are both x-polarized. The distance between the center of the slot end of the Vivaldi antenna and the transflective array is 150 mm, and the distance between the center of the horn mouth of the broadband horn antenna and the transflective array is 150 mm.

[0027] Figure 2 The top view of the four-layer transflective array is given. The transflective array consists of 25×25 unit structures and the array size is 250×250mm. 2 .

[0028] Figure 3 The schematic diagram of the unit structure that constitutes the transflective array is shown. It consists of five metal layers and four dielectric plates. The dielectric plates are all F4B plates with a dielectric constant of 2.65 and a loss angle of 0.001.

[0029] Figure 4 The schematic diagram of the structure of the metal layer constituting the transflective unit is shown, 4(a) is the top metal layer, 4(b) is the second metal layer, 4(c) is the third metal layer, and 4(d) is the fifth metal layer. The length of the metal strip in 4(a) is 0.75 times the length of the metal strip in 4(b). 4(e)-4(l) are eight specific structures of the fourth metal layer, named structure 000-structure 111, respectively, and their specific parameters are w1=1mm, l1=3.6mm, l2=9.9mm, g1=0.3mm, w2=0.5mm, r1=4.5mm, α1=12°, w3=0.7mm, α2=42°, r2=4.5mm, g2=1.2mm, w4=0.5mm.

[0030] Figure 5 Shows that by changing l x The structure of the fourth metal layer realizes the three-bit phase modulation of the x-polarized wave co-polarization reflection and the y-polarized wave polarization conversion transmission respectively. Figure 6 , we demonstrated that there is good independence between the three-bit phase modulation of transmission and reflection.

[0031] We designed the following for the x-polarized incident wave excited by the 10-structure: Figure 7 The co-polarized reflection phase distribution shown in (a) is designed for the x-polarized incident wave excited by the 20 structure. Figure 7 The polarization-converted transmission phase distribution shown in (b) is calculated by the following formulas:

[0032]

[0033]

[0034] where Φ 10 and Φ 20 are the phase shift values ​​at the coordinates (x, y) of the x-polarized incident wave excited by the 10-structure and 20-structure respectively, λ is the free space wavelength at the design frequency of 13 GHz, F1 is the focal length designed for the 10-structure, specifically 167.5 mm (the phase center of the Vivaldi antenna is 17.5 mm from the center of the slot line end), F2 is the focal length designed for the 20-structure, specifically 202 mm (the phase center of the broadband horn antenna is 52 mm from the center of the horn mouth surface), Φ1 and Φ2 are the reference phases.

[0035] Figure 8 In the figure, 8(a) is the three-dimensional far-field distribution diagram at a frequency of 13 GHz when the 10 structures are excited by an x-polarized incident wave in the -z direction, and 8(b) is the three-dimensional far-field distribution diagram at a frequency of 13 GHz when the 20 structures are excited by an x-polarized incident wave in the +z direction. It can be found that in both cases, a high-gain beam is generated that is emitted along the +z direction, and the polarization mode of the high-gain beam in 8(a) is x-polarization, and the polarization mode of the high-gain beam in 8(b) is y-polarization.

[0036] Fig. 9 In Figure 9(a), the broadband normal gain of the reflected beam when the structure 10 excites the x-polarized incident wave, and the corresponding change in the broadband range of the aperture efficiency. It can be found that when the dual-channel transflective receiving antenna works in the reflection mode, it can achieve an antenna gain of more than 20dB in the frequency range of 10.5-16.5GHz. The high-gain beam polarization mode is x-polarization, reaching a peak gain of 27dB at 12GHz, a peak aperture efficiency of 40%, a 3dB gain bandwidth of 11-16GHz, and a relative bandwidth of 37%.

[0037] Fig. 9 In Figure 9(b), the broadband normal gain of the transmitted beam when the 20 structure excites the x-polarized incident wave, and the corresponding change in the broadband range of the aperture efficiency. It can be found that when the dual-channel transflective receiving antenna works in the transmission mode, it can achieve an antenna gain of more than 20dB in the frequency range of 9-18GHz. The high-gain beam polarization mode is y-polarization, reaching a peak gain of 28dB at 14GHz, a peak aperture efficiency of 39%, a 3dB gain bandwidth of 11.5-17GHz, and a relative bandwidth of 38%.

[0038] In summary, when the broadband dual-channel transflective receiving antenna works in the transmitting mode, it can form x-polarized and y-polarized high-gain beams emitted in the +z direction for the x-polarized spherical waves emitted by the two feed antennas within a wide frequency range of the X and Ku bands. According to the reversible principle of the optical path, when it works in the receiving mode, it can also achieve reflection focusing and transmission focusing for the x and y polarized electromagnetic waves incident along the -z direction within a wide frequency range of the X and Ku bands, and then effectively receive them through the Vivaldi antenna and the broadband horn antenna respectively. The broadband dual-channel transflective receiving antenna has the advantages of high efficiency, wide frequency band, low profile, and independent dual channels, and has great application potential in the engineering field.

Claims

1. A broadband dual-channel transflective receiving antenna, characterized in that: The invention comprises a Vivaldi antenna, a broadband horn antenna and a four-layer transflective array; wherein the four-layer transflective array is composed of dual-channel transflective units working in the X and Ku bands; the transflective array is composed of four dielectric plates and five metal layers, wherein the third and fifth layers are orthogonal metal gratings, the first and second layers are co-polarized reflection phase modulation layers for x-polarized incident waves, and the fourth layer is a polarization-converting transmission phase modulation layer for y-polarized incident waves.

2. The broadband dual-channel transflective receiving antenna according to claim 1, characterized in that: The Vivaldi antenna adopts a microstrip line to slot line structure, which can effectively radiate spherical waves in the X and Ku bands, and its polarization direction is consistent with the opening direction of the slot line; and the broadband horn antenna can also effectively radiate spherical waves in the X and Ku bands, and its polarization mode is consistent with the short side direction of the horn opening.

3. The method for setting up a broadband dual-channel transflective receiving antenna according to any one of claims 1 to 2, characterized in that: The receiving terminal is composed of an x-polarized Vivaldi antenna and an x-polarized broadband horn antenna. The Vivaldi antenna is located on the +z side of the transflective array, and the broadband horn antenna is located on the -z side of the transflective array. The geometric centers of the Vivaldi antenna, the horn antenna and the transflective array are located on a straight line. The x-polarized spherical waves emitted by the Vivaldi antenna in the X and Ku bands are reflected by the transflective array as an x-polarized high-gain beam emitted in the +z direction; while the x-polarized spherical waves emitted by the horn antenna in the X and Ku bands are transmitted by the transflective array as a y-polarized high-gain beam emitted in the +z direction; based on the reversible principle of the optical path, the antenna can also achieve spatial separation and independent reception of dual-channel x-polarized and y-polarized electromagnetic waves incident in the -z direction of the same band.

4. The method for setting up a broadband dual-channel transflective receiving antenna according to claim 3, characterized in that: The four-layer transflective array is composed of 25*25 transflective units working in the X and Ku bands; the dual-channel transflective unit is composed of four dielectric plates and five metal layers, wherein the third and fifth metal layers are orthogonal metal gratings, the first and second metal layers are reflection phase modulation layers, and the fourth metal layer is a transmission phase modulation layer; by changing the lengths of the first and second metal strips, a 3-bit modulation is formed on the co-polarization reflection phase of the x-polarized wave incident along the -z direction; by designing four structures for the fourth metal layer and taking mirror operations, a 3-bit modulation is formed on the polarization-transmitted phase of the y-polarized wave incident along the +z direction; what is particularly important is that there is almost no crosstalk and influence between the two transflective 3-bit modulations, thereby ensuring the independent modulation of the dual-channel transflective.

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