Narrow-pulse ns-level time delay compensation type plane reflection array antenna

Abstract

The invention discloses a narrow pulse ns-level time delay compensation type plane reflection array antenna, and belongs to the technical field of antennas. The array antenna comprises a reflective array antenna and a feed source, and each array element in the reflective array antenna performs corresponding time delay compensation on electromagnetic waves emitted by the feed source according to the distance between the array element and the feed source so as to improve the gain of a reflective wave beam in an expected direction. According to the invention, a time delay type compensation method is adopted to enable the pulse signals fed into the plane reflection antenna array to realize simultaneous, equal-amplitude and same-phase superposition in a far field, so that the time domain pulse distortion phenomenon is avoided, the time delay compensation of electromagnetic waves fed into the plane reflection antenna array can be effectively realized, and the antenna gain and the fidelity of received signals are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to the design of a time-delay compensation type planar reflection array antenna. Background Art

[0002] As an important component of high-power microwave systems, the main function of antennas is to achieve directional radiation of electromagnetic energy. Although traditional parabolic antennas have high radiation efficiency and strong directivity, their curved structures are difficult to process and are large in size. Phased array antennas have flexible beam scanning, but require complex phase shifting networks and TR components, and their electronic components are difficult to use in high-power microwave environments. Planar reflectarray antennas have the advantages of both parabolic antennas and phased array antennas. They not only have a low profile and are easy to process, but also have high gain and controllable beam direction. They have good application prospects in the field of high-power microwaves.

[0003] According to the working mechanism of the planar reflective array antenna, the electromagnetic waves emitted by the feed source have different path lengths to reach different elements of the planar reflective array. Existing planar reflective array antennas use a phase-shifting compensation method to calculate the phase difference of the electromagnetic waves received by each unit within a relative phase change range of 360° and compensate for the phase difference, thereby achieving the effect of plane wavefront radiation. The phase-shifting compensation method only considers the phase alignment of the received pulse signal, without considering the time domain performance of the antenna. However, typical high-power microwave signals are mostly narrow pulse waveforms. When applied to large-aperture reflective antennas, it is easy for electromagnetic waves with short transmission paths to reach the receiving antenna, while electromagnetic waves with long transmission paths are still far from arriving. On the one hand, this phenomenon shows that the utilization rate of the array elements in the reflective array is reduced, resulting in a decrease in the gain of the reflective array. For Figure 1 The antenna size shown in the figure is fed with a typical high-power microwave signal, and the obtained antenna gain changes with time as shown in Figure 2 As shown in the figure, the gain reaches a peak at certain moments, but the overall level is low, which indicates that the signals fail to effectively superimpose at the same time, resulting in a decrease in the far-field gain of the antenna. On the other hand, the time delay caused by the path difference slows down the front edge of the received pulse signal, lengthens the length, and reduces the peak duration, causing time domain waveform distortion. Therefore, this time delay needs to be compensated. In order to ensure the application effect of planar reflective array antennas under high-power microwave conditions, it is urgent to develop narrow pulse delay compensation technology. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention proposes a time-delay compensation planar reflection array antenna. The array antenna adopts a time-delay compensation method to achieve simultaneous equal-amplitude and in-phase superposition of pulse signals fed into the planar reflection antenna array in the far field, thereby avoiding the time domain pulse distortion phenomenon and effectively realizing the time delay compensation of the electromagnetic waves fed into the planar reflection antenna array.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A time-delay compensation planar reflective array antenna, comprising a reflective array antenna and a feed source;

[0007] The feed source is arranged at a certain position in front of the reflective array antenna;

[0008] The reflectarray antenna is a planar reflectarray antenna composed of a plurality of array elements;

[0009] The characteristic is that each array element in the reflective array antenna performs corresponding time delay compensation on the electromagnetic wave emitted by the feed source according to the distance between the array element and the feed source, thereby improving the gain of the reflected beam in the expected direction.

[0010] Preferably, the delay compensation value of the array element is in, i,j represents the array element in the i-th row and j-th column. d ij is the distance that the electromagnetic wave takes to reach the array element, and c is the speed of light.

[0011] Preferably, phase compensation is performed on array elements at different positions, and the gain of the reflected beam in the expected direction is further optimized by joint compensation of phase shift and time delay.

[0012] Preferably, the array element comprises a radiation patch layer, a first dielectric substrate layer, an aperture coupling layer, a second dielectric substrate layer, and a delay compensation circuit layer which are stacked in sequence from top to bottom;

[0013] The radiation patch layer includes a metal radiation patch;

[0014] The aperture coupling layer is a metal plate with a coupling through hole in the middle;

[0015] The delay circuit layer is composed of metal patches to form a delay circuit, providing time delay compensation for the array elements;

[0016] The electromagnetic waves radiated by the feed source are irradiated to the radiation patch layer, and are coupled to the delay circuit through the coupling through hole below it. After delay compensation, the electromagnetic waves are reflected to the free space to achieve a high-gain reflected beam in the expected direction.

[0017] Preferably, the metal radiation patch is a square metal patch;

[0018] The coupling through hole is a bowtie-shaped through hole, and the bowtie-shaped through hole is composed of two opposite fan-shaped through holes;

[0019] The delay circuit includes at least one hairpin resonance unit, a microstrip signal input line and a microstrip open line; wherein one end of the microstrip signal input line is located directly below the coupling through hole, and the other end is connected to the first stage of the hairpin resonance unit; the hairpin resonance units are U-shaped and arranged at intervals in the same direction, and the openings of two adjacent hairpin resonance units face opposite directions; one end of the microstrip open line is connected to the last stage of the hairpin resonance unit, and the other end is open.

[0020] Preferably, the planar reflection array antenna adopts forward feeding or offset feeding.

[0021] The working principle of the time-delay compensation planar reflective array antenna is as follows: Since the time required for the pulse signal to reach different positions of the reflective array antenna from the feed horn is different, that is, the electromagnetic waves received by the array elements at different positions have different delays, the delay compensation antenna unit is used to perform corresponding delay compensation on the array elements at different positions, and the radiation of narrow pulse signals can be finally achieved. In addition, the phase compensation is performed on the array elements at different positions, and the gain of the reflected beam in the expected direction is further optimized through the joint compensation of phase shift and delay.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The antenna of the present invention adopts a time delay compensation method, which can be used to compensate for the time delay in a short pulse application environment and improve the antenna gain and the fidelity of the received signal.

[0024] 2. The antenna of the present invention achieves the required delay compensation and phase compensation by adjusting the delay value and phase compensation value of the delay circuit, thereby improving the degree of freedom and flexibility of design.

[0025] 3. Compared with traditional parabolic antennas and phased array antennas, the antenna designed in the present invention has a low profile, is easy to process, does not require a complex phase shift network and TR components, and has controllable beamforming direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of a partitioned structure planar reflective array antenna according to an embodiment of the present invention.

[0027] Figure 2 This is a graph showing the gain versus time variation of the present invention.

[0028] Figure 3 It is a three-dimensional stereoscopic view of the reflective antenna unit described in an embodiment of the present invention.

[0029] Figure 4 It is an exploded view of the reflective antenna unit described in an embodiment of the present invention.

[0030] Figure 5It is a side view of the reflective antenna unit according to an embodiment of the present invention.

[0031] Figure 6 It is a top view of the reflective antenna unit described in an embodiment of the present invention.

[0032] Figure 7 It is a simulation diagram of a time delay curve of an embodiment of the present invention.

[0033] Figure 8 FIG. 4 is a graph showing gain variation with frequency according to an embodiment of the present invention.

[0034] Fig. 9 This is a diagram marking key parameters of the resonance unit according to an embodiment of the present invention.

[0035] Fig.10 Graph showing the relationship between the resonance unit and the delay value in an embodiment of the present invention.

[0036] Fig.11 Graph showing the relationship between microstrip line length and phase change in an embodiment of the present invention.

[0037] Explanation of the accompanying drawings: 1. Feed antenna; 2. Planar reflection antenna array; 3. Radiating patch; 4. First dielectric substrate; 5. Aperture coupling layer; 6. Second dielectric substrate; 7. Delay compensation circuit. DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with the accompanying drawings. It should be noted that the specific embodiments given below are further implemented under the premise of the technical solution of the present invention, and are only for the purpose of illustrating the present invention in more detail, but are not limited thereto.

[0039] This embodiment provides a delay compensation type planar reflection array antenna, such as Figure 1 As shown, it includes a reflect array antenna and a feed source.

[0040] The center frequency of the feed source is 9.5 GHz, and it is arranged in front of the reflective array antenna, and feeds electromagnetic waves into the reflective array antenna in a forward feeding manner;

[0041] The reflectarray antenna is a planar reflectarray antenna composed of a plurality of array elements;

[0042] The array element, such as Figure 3-Figure 6 As shown, it includes a radiation patch, a first dielectric substrate, an aperture coupling layer, a second dielectric substrate, and a delay compensation circuit which are stacked in sequence from top to bottom.

[0043] The radiation patch is a square metal patch with a side length of 9.5 mm, and the center thereof coincides with the central axis of the array element.

[0044] The material of the first dielectric substrate layer is Rogers 5880, the substrate size is 15 mm×15 mm, and the substrate thickness is 0.508 mm.

[0045] The aperture coupling layer is a metal layer with a coupling through hole in the middle, and the size of the metal layer is 15mm×15mm; the coupling through hole is a bowtie-type through hole, and the bowtie-type through hole is composed of two opposite fan-shaped through holes, the radius of the fan-shaped through hole is 1.35mm, the central angle is 60°, and the width of the fan-shaped through holes at the junction is 0.15mm.

[0046] The material of the second dielectric substrate layer is Rogers 6010, the substrate size is 15 mm×15 mm, and the thickness is 0.635 mm.

[0047] The delay circuit layer is composed of metal patches to form a delay circuit, which provides time delay compensation for the array element; the delay circuit includes at least one hairpin resonant unit, a microstrip signal input line and a microstrip open line; wherein the microstrip signal input line has a width of 0.55 mm and is bent to reduce the size of the array element, one end of which is located directly below the coupling through hole, and the other end is connected to the first level of the hairpin resonant unit; the hairpin resonant units are U-shaped and arranged at intervals in the same direction, and the openings of two adjacent hairpin resonant units are in opposite directions; the microstrip open line has a width of 0.55 mm, one end of which is connected to the last level of the hairpin resonant unit, and the other end is open.

[0048] The electromagnetic waves radiated by the feed source are irradiated to the radiation patch, and are coupled to the delay circuit through the coupling through hole below it. After delay compensation, the electromagnetic waves are reflected into the free space to achieve a high-gain reflected beam in the expected direction.

[0049] First, the same delay is applied to each element of the reflect array antenna in this embodiment: the distance between the feed antenna and the center of the reflect array antenna is L1 = 140 mm, and the radius of the reflect array antenna is 70 mm. The delay compensation value of each element in the reflect array antenna is the same, and the final simulation result is as follows: Figure 7 and Figure 8 As shown, the results show that in the range of 9.45GHz-9.55GHz, the antenna can achieve a time delay of 5.1ns, a main beam gain of 22.8dBi, a 3dB beam bandwidth of 11.3°, and a sidelobe level of -17.7dB. This shows that the planar reflectarray antenna in this implementation has the ability to compensate for time delays, that is, in the implementation process, the time delay value of the time delay compensation structure can be adjusted to design the time delay compensation units required in different areas.

[0050] Different time delays are applied to the array elements of the reflectarray antenna of this embodiment to achieve a high-gain reflected beam in a desired direction: assuming that the distance between the feed antenna and the center of the reflectarray antenna is L2=0.6m, the distance to the edge of the reflecting surface is L3=1.8m, and the array radius of the reflectarray antenna is 1.7m.

[0051] Step 1: Calculate that the central element of the reflectarray antenna needs to compensate for a 4ns time delay. Assuming the time delay compensation accuracy is 0.5ns, the delay compensation value gradually decreases from the center to the edge of the reflecting surface with a gradient of 0.5ns. The calculated delay compensation values ​​required for the reflectarray antenna elements are shown in Table 1.

[0052] Step 2: Divide the area by the delay compensation value calculated in the previous step, as shown in Table 2. The delay compensation value required for the same area is the same. Step 3: Set up array elements with corresponding delays in each divided area; since the time delay compensation capability of the array elements mainly comes from the hairpin resonator, the overall time delay value of the multi-stage resonator is adjusted by adjusting the delay value of a single resonator and the number and spacing of series resonators to achieve the desired delay compensation value. The key parameters of the resonator are Fig. 9 As shown in Figure 2, the results of changing the number and size of the resonant units in the resonator are as follows: Fig.10 The specific parameters are shown in Table 3. It can be seen that the designed multi-stage resonant structure can meet the time delay compensation requirements of the array element. The reflectarray antenna obtained at this time realizes a high-gain reflection beam in the desired direction through time delay compensation. On the basis of delay compensation, in this embodiment, phase compensation can be further achieved by adjusting the length of the input and output microstrip lines. Taking the resonant structure used in region I as an example, by adjusting the length of its input microstrip line, the relationship between the length of the microstrip line and the phase change can be obtained. The result is as follows: Fig.11 As shown; the other regions also use the same method to achieve phase compensation. Finally, the reflect array antenna obtained by the joint compensation of phase shift and time delay can achieve a high-gain reflection beam with further optimized performance.

[0053] Table 1 Delay compensation values ​​required for reflector array elements

[0054]

[0055] Table 2 Reflection surface area division

[0056]

[0057] Table 3 Resonator delay values ​​and key parameters in different regions

[0058]

[0059] The above description is only used to describe the present invention, and the present invention is not limited by the above embodiments. Any improvements, equivalent replacements, etc. made by those skilled in the art based on the present invention shall all fall within the protection scope of the present invention.

Claims

1. A time-delay compensation planar reflective array antenna, comprising a reflective array antenna and a feed source; The feed source is arranged at a certain position in front of the reflective array antenna; The reflectarray antenna is a planar reflectarray antenna composed of a plurality of array elements; It is characterized in that Each array element in the reflective array antenna performs corresponding time delay compensation on the electromagnetic wave emitted by the feed source according to the distance between the array element and the feed source, thereby improving the gain of the reflected beam in the expected direction.

2. A time-delay-compensated planar reflective array antenna as claimed in claim 1, characterized in that: The delay compensation value of the array element is in, i,j represents the array element in the i-th row and j-th column, d ij is the distance that the electromagnetic wave takes to reach the array element, and c is the speed of light.

3. A time-delay-compensated planar reflective array antenna as claimed in claim 1 or 2, characterized in that: Phase compensation is performed on array elements at different positions, and the gain of the reflected beam in the expected direction is further optimized through joint compensation of phase shift and time delay.

4. A time-delay-compensated planar reflectarray antenna as claimed in claim 3, characterized in that: The array element comprises a radiation patch layer, a first dielectric substrate layer, an aperture coupling layer, a second dielectric substrate layer, and a delay compensation circuit layer which are stacked in sequence from top to bottom; The radiation patch layer includes a metal radiation patch; The aperture coupling layer is a metal plate with a coupling through hole in the middle; The delay circuit layer is composed of metal patches to form a delay circuit, providing time delay compensation for the array elements; The electromagnetic waves radiated by the feed source are irradiated to the radiation patch layer, and are coupled to the delay circuit through the coupling through hole below it. After delay compensation, the electromagnetic waves are reflected to the free space to achieve a high-gain reflected beam in the expected direction.

5. A time-delay-compensated planar reflective array antenna as claimed in claim 4, characterized in that: The metal radiation patch is a square metal patch; The coupling through hole is a bowtie-shaped through hole, and the bowtie-shaped through hole is composed of two opposite fan-shaped through holes; The delay circuit includes at least one hairpin resonance unit, a microstrip signal input line and a microstrip open line; wherein one end of the microstrip signal input line is located directly below the coupling through hole, and the other end is connected to the first stage of the hairpin resonance unit; the hairpin resonance units are U-shaped and arranged at intervals in the same direction, and the openings of two adjacent hairpin resonance units face opposite directions; one end of the microstrip open line is connected to the last stage of the hairpin resonance unit, and the other end is open.

6. A time-delay-compensated planar reflective array antenna according to any one of claims 3 to 5, characterized in that: The planar reflection array antenna adopts forward feeding or offset feeding.

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