CN107104287A - Wideband single layer polarization beam splitting research of planar reflectarray antennas based on overlapping reflector element - Google Patents

Abstract

The invention discloses a broadband single-layer polarized beam-splitting plane reflection array antenna based on overlapping reflection units, which includes a feed source horn and a plane reflection array. The reflective unit of the planar reflective array is composed of two groups of parallel monopoles stacked orthogonally, which are respectively used to compensate the reflection phases of linearly polarized waves in the X direction and linearly polarized waves in the Y direction. The independent control of the two polarized reflection beams achieves the effect of beam polarization separation.

Description

Broadband Single Layer Polarized Beamsplitting Planar Reflectarray Antenna Based on Overlapping Reflecting Elements

Technical field:

The invention relates to a broadband single-layer polarization beam splitting planar reflection array antenna based on overlapping reflection units, which belongs to the field of electronic communication.

Background technique:

A flat reflectarray is an antenna form that combines a reflective parabola and an array antenna. The reflection phase is corrected by designing the structural parameters of each unit on the array, so that it can obtain an equiphase plane in a certain direction of the far field, and obtain a radiation beam in this direction. Compared with the traditional parabolic reflector antenna, the structure has a low cross-section, small footprint, light weight, simple processing and low cost; it can be folded and unfolded, and is convenient for space applications. Compared with the array antenna, the planar reflectarray saves the complicated feeding and power dividing network, which makes the energy transmission efficiency higher and reduces the difficulty of design. The most important thing is that once the reflection unit is determined, it can be applied to a multi-purpose planar array. By adjusting the structural size of the surface reflection unit, an antenna that can meet the requirements of different frequency bands and different beams can be obtained.

The planar reflectarray has inherent disadvantages: the path difference from the feed source to each reflective unit on the front is a function of frequency, and as the frequency changes, the spatial phase difference that each reflective unit needs to compensate also changes. However, the size of the reflective unit is fixed, and the frequency deviation exceeds the design, which will inevitably cause problems such as gain drop and beam deviation, which makes the traditional planar reflective array have inherent narrow-band operating characteristics, and it is difficult to achieve broadband and multi-frequency operation. The multi-resonant unit structure means that the reflection unit contains patches of similar size and shape, which can effectively expand the working bandwidth without increasing the array section. The parallel monopole structure used in the present invention obtains a working bandwidth of 15.7%, and the phase regulation curve of the reflection unit is linear in the range of 11.3-13.4GHz and covers a variation range of more than 360°. In addition, the present invention realizes the separation of reflected waves of different polarization modes on the same plane, and makes each beam point to its own designed space direction. The polarized beam multiplexing expands the channel capacity and improves the efficiency of the antenna.

Invention content:

The invention provides a broadband single-layer polarized beam-splitting plane reflection array antenna based on overlapping reflection units, and the structure of the invention can well improve the working bandwidth of the plane reflection array. At the same time, the invention realizes the separation of reflected beams of different polarization modes on the same plane, and the beam spatial direction of each polarization mode can be independently designed.

The technical solutions adopted in the present invention include: a broadband single-layer polarization splitting planar reflective array antenna based on overlapping reflective units, which is composed of a feed horn and a planar reflective array. The planar reflective array includes a dielectric substrate, a grounded metal back plate and an air layer that separates the dielectric substrate from the grounded metal backplane. Reflection units are arranged on the surface of the dielectric substrate, and each reflection unit is composed of two groups of parallel monopoles stacked orthogonally.

Furthermore, two sets of parallel monopoles in the reflection unit are stacked orthogonally on the surface, and the phases of the linearly polarized waves in the X direction and the linearly polarized waves in the Y direction are independently phase-regulated, so that the same planar reflective array can control two kinds of orthogonal Multiplexing of linearly polarized waves.

Further, the reflection unit is a single-layer metal patch, the dielectric substrate is made of ARLON 25N material with a thickness of 0.508 mm, and the thickness of the air layer is 3 mm.

The present invention has the following beneficial effects: First, the present invention uses a single-layer metal patch to realize the multiplexing of dual-polarization, and two sets of parallel monopoles are stacked orthogonally on the same plane, reducing the profile and greatly reducing the processing difficulty . In addition, orthogonal parallel monopoles have good polarization isolation characteristics. Each group of parallel monopoles corresponds to a polarization mode, which can realize independent control of two polarized reflection beams, thus greatly improving the reliability of planar reflective array design. flexibility. Finally, the parallel monopoles with multi-resonance characteristics cooperate with the air layer structure to ensure that the planar reflectarray can achieve stable broadband operation.

Description of drawings:

Fig. 1 is a schematic diagram of the system structure of the present invention.

Fig. 2 is a structural diagram of the reflection unit, (a) is a top view, and (b) is a side view.

Fig. 3 is a structure diagram of a parallel monopole, (a) is a top view, (b) is a side view.

Figure 4 is the phase compensation curve of the parallel monopole under the linearly polarized incident wave in the X direction, (a) is the parallel monopole placed along the y-axis, and (b) is placed along the x-axis.

Fig. 5 is a schematic diagram of a reflection unit formed by stacking orthogonal parallel monopoles.

Fig. 6 is a phase compensation curve of the reflection unit under the incident wave of linear polarization in the X direction and linear polarization in the Y direction, (a) linear polarization in the X direction, and (b) linear polarization in the Y direction.

FIG. 7 is a structural diagram of a planar reflective array.

Fig. 8 is the radiation pattern of the planar reflectarray, (a) is a schematic diagram of structure arrangement, (b) is the radiation pattern of linear polarization in X direction, and (c) is the radiation pattern of linear polarization in Y direction.

in:

1-feed horn, 2-plane reflection array, 3-reflection unit, 4-parallel monopole, 5-dielectric substrate, 6-air layer, 7-grounded metal backplane.

detailed description:

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 1 , the overall structure of the wideband single-layer polarization beam splitting planar reflectarray antenna based on overlapping reflecting units is composed of a feed horn 1 and a planar reflectarray 2 . The feed horn provides excitation; the reflection unit 3 on the surface of the planar reflection array is composed of two groups of parallel monopoles 4 stacked orthogonally, and each group of parallel monopoles is arranged along the x-axis and y-axis respectively. Each group of parallel monopoles can adjust the reflection phase of the linearly polarized waves in the arrangement direction, but cannot adjust the phase of the linearly polarized waves in the orthogonal direction. Two sets of parallel monopoles are stacked orthogonally to obtain a complete reflection unit, which can realize independent control of the phases of the X-direction linear polarization and the Y-direction linear polarization reflection wave. The reflection unit on the planar reflector array adjusts the phase by changing the size, and compensates the spatial phase difference of the feed horn irradiating the planar reflector array, so that the whole planar reflector array obtains an equiphase plane in a certain far-field direction, and realizes in-phase addition. This results in a radiation beam in that direction. When dual linear polarization or circular polarization is incident, the parallel monopole arrangements of the y-axis and x-axis in the planar reflectarray are independently designed to achieve linear polarization in the X direction and Y-axis on the same plane reflectarray surface. Directional linear polarization reflection beams are separated, and the beams point to the designed direction. Each group of parallel monopoles in the reflection unit adopts a multi-resonance structure design, and the dielectric substrate 5 of the reflection unit 3 and the grounded metal backplane 7 are separated by an air layer 6, forming a smooth phase compensation spanning 360° The curve makes the reflected beam maintain stable directivity and gain in a wide frequency band.

Figure 2 shows the structural diagram of the reflection unit. The dielectric substrate 5 is made of ARLON 25N material with a thickness of 0.508mm. The dielectric substrate 5 and the grounded metal backplane 7 are separated by an air layer 6 of 3 mm. The air layer 6 ensures that the phase adjustment curve spans 360°. The metal patch structure on the surface of the dielectric substrate 5 is two groups of parallel monopoles 4 stacked orthogonally.

Figure 3 shows a set of parallel monopoles placed along the y-axis in a reflector unit. The size of the reflection unit is a square area with side length a _x =a _y =16.5 mm. The three parallel monopoles are arranged equidistantly with a spacing of 5.5mm, and the width of the parallel monopoles is w=1mm. The length of the central parallel monopole is l ₁ , the length of the parallel monopoles on both sides is l ₂ , and keep l ₂ =0.7l ₁ . When the incident wave is linearly polarized in the X direction, the phase compensation curve of the parallel monopole is shown in Fig. 4(a). It can be seen from the figure that between 11.3GHz and 13.4GHz, as the length of the central parallel monopole _l1 changes between 6-10mm, the phase compensation curves at each frequency point change roughly linearly, and the change range is greater than 360 °.

Also under the linearly polarized incident wave in the X direction, the phase compensation curve of the parallel monopole placed along the x-axis is shown in Fig. 4(b). The reflection phase of each frequency point does not change with the change of the length l ₁ of the central parallel monopole. Two sets of orthogonal parallel monopoles are stacked to form a reflection unit, as shown in Figure 5. The phase adjustment curve of the complete reflection unit is shown in Fig. 6, Fig. 6(a) is the case of X-direction linear polarization, and Fig. 6(b) is the case of Y-direction linear polarization. In both cases, the length of the central parallel monopole varies between 5-10mm, and smooth near-linear phase compensation curves are obtained at each frequency point between 11.3GHz and 13.4GHz, and the phase variation range exceeds 360°.

Taking advantage of the good polarization isolation of this structure, a planar reflective array can be designed to realize the degree-independent control of the X-direction and Y-direction linearly polarized reflected beams, and the same planar reflective array can be used to generate two beams with different polarization modes and different spatial orientations. reflected beam. As shown in Figure 8(a), the planar reflectarray is placed in the xy plane, the coordinate origin is located at the center of the planar reflectarray, and the feed horn is placed on the z-axis. In this patent, the reflected beams set are all located in the yz plane, the azimuth angle of the linearly polarized reflected beam in the X direction is (θ ₁ =15°, φ ₁ =0°), and the azimuth angle of the linearly polarized reflected beam in the Y direction is (θ ₂ =-15°, φ ₂ =0°), the planar reflective array thus designed is shown in FIG. 7 .

Figure 8(b) shows the pattern of the linearly polarized reflected beam in the X direction. In the yz plane shown in Figure 8(a), the maximum gain of the reflected beam pattern of 11.3GHz-13.1GHz is located at the designed (θ ₁ =15°, φ ₁ =0°) direction, the beam gain reaches a maximum of 28.12dB at 12.2GHz, and a sidelobe with a gain greater than 10dB appears at 13.1GHz. Figure 8(c) shows the Y-direction linearly polarized reflected beam pattern in the yz plane, also within 11.3GHz-13.1GHz, the maximum gain direction is (θ ₂ =-15°, φ ₂ =0°) , the maximum gain is 27.98dB at 12.2GHz.

The reflective unit described in the present invention has strong design flexibility, and the spatial orientation of the reflected beams of the two polarization modes can be freely designed. This patent only describes a specific design, and other various beam designs are within the protection rights required by this patent.

Claims (3)

1. A broadband single-layer polarization beam splitting planar reflectarray antenna based on overlapping reflection units, characterized in that: it is made up of a feed horn (1) and a planar reflectarray (2), and the planar reflectarray (2) includes A dielectric substrate (5), a grounded metal backplane (7), and an air layer (6) separating the dielectric substrate (5) from the grounded metal backplane (7), and a reflection unit (3) arranged on the surface of the dielectric substrate (5) ), each reflection unit (3) is composed of two groups of parallel monopoles (4) stacked orthogonally. 2. The broadband single-layer polarization beam splitting planar reflectarray antenna based on overlapping reflective elements as claimed in claim 1, characterized in that: in the reflective elements (3), two groups of parallel monopoles (4) overlap on the surface The linearly polarized wave in the X direction and the linearly polarized wave in the Y direction are independently phase-regulated to realize the multiplexing of two orthogonal linearly polarized waves by the same planar reflective array (2). 3. The broadband single-layer polarization beam splitting planar reflectarray antenna based on overlapping reflective elements as claimed in claim 1, characterized in that: the reflective element (3) is a single-layer metal patch, and the dielectric substrate (5 ) using ARLON 25N material with a thickness of 0.508mm, and the thickness of the air layer (6) is 3mm.