A narrow-pulse time-delay-compensated planar transmit array antenna

Abstract

The application provides a narrow-pulse time delay compensation type planar transmission array antenna and belongs to the technical field of antennas. The antenna comprises a transmission array antenna and a feed antenna; each array element in the transmission array antenna performs time delay compensation on electromagnetic waves emitted by the feed antenna according to the spacing between the array element and the feed antenna, so as to improve the gain of a reflected beam in an expected direction; the array element comprises a time shift structure and a phase shift structure; in the time shift structure, the time delay amount of the time shift structure is adjusted by adjusting the gap size and controlling the coupling between multiple resonances. The application compensates for the time delay difference caused by the different spatial distances between the feed and the array elements in the process of narrow-pulse transmission by using the time delay compensation technology, thereby improving the gain of the planar transmission array antenna and reducing the distortion of the time domain signal; and the application has the advantages of small profile height, easy processing and simple design.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of antennas, and particularly relates to a narrow pulse time delay compensation planar transmission array antenna. BACKGROUND

[0002] With the rapid development of modern communication technology, the importance of antennas as a "converter" for receiving and transmitting electromagnetic waves, an important information carrier, is self-evident. In radar systems, aviation satellites and other aspects, high-gain antennas are more favored. Parabolic antennas and phased array antennas are often chosen as antenna types that can meet the above characteristics. A parabolic antenna is composed of a parabolic reflecting surface and a feed source, and usually has high gain, strong anti-interference ability and directivity. However, the parabolic antenna usually needs a large size, the body is heavy, and its special parabolic surface has a high requirement for processing precision. A phased array antenna needs a large number of phase shifters, and the feed network is complex, which reduces the efficiency of the antenna and increases the design difficulty of the antenna. A planar array antenna can effectively solve the above problems, and combines the advantages of parabolic antennas and phased array antennas.

[0003] High power microwave (HPM) refers to microwave radiation with a frequency of hundreds of megahertz to tens of gigahertz and an output power of several megawatts to several kilowatts, which is often used in military and national defense security fields. The typical waveform of high power microwave is a narrow pulse. When a large-aperture planar reflectarray antenna receives and transmits a narrow pulse wave, the performance of the antenna will be affected due to insufficient unit time delay compensation capability. Figure 1 The power graphs of planar array antennas with and without time delay compensation when transmitting narrow pulse waves are displayed and compared. The pulse beam with a rising edge and a falling edge of 5ns and a peak value of 2ns is used. It can be seen that the received power of the antenna without time delay compensation changes compared with the antenna with time delay compensation capability, which is specifically manifested in that the pulse beam is lengthened, the rising edge and the falling edge are slowed down, and the peak time is shortened. It can be seen that the peak power of the antenna with time delay compensation is about 3dB higher than that of the antenna without time delay compensation. As shown in Figure 2 The equivalent irradiation unit of the antenna array surface irradiated by the simulated horn transmitting a narrow pulse beam changes with time. It can be obviously seen that at different times, the antenna cannot be completely illuminated, so that the units on the array surface cannot work at the same time, thereby reducing the antenna gain.

[0004] Therefore, exploring time delay compensation techniques for planar arrays under narrow pulse waves is of great significance. A common time delay compensation method in existing technologies is direct coupling of microstrip lines for linear time adjustment. However, this method suffers from the problem of excessively long microstrip lines when the required time delay compensation is large. For example, when the array radius is 1.37m and the distance between the feed horn and the array center is 0.6m, the maximum required time delay compensation is 3ns, corresponding to a microstrip line length of 0.45m. Clearly, such a long line results in an excessively high profile and makes installation and fabrication difficult. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a narrow-pulse time-delay compensated planar transmission array antenna. This invention effectively compensates for the time delay of electromagnetic waves fed into the planar transmission antenna array while maintaining the antenna profile height.

[0006] The technical solution adopted in this invention patent is as follows:

[0007] A narrow pulse delay-compensated planar transmission array antenna, comprising a transmission array antenna and a feed antenna;

[0008] The feed antenna provides excitation to the transmission array antenna using a positive feed method.

[0009] The transmission array antenna is composed of several array elements;

[0010] The characteristic feature is that each element in the transmission array antenna performs corresponding time delay compensation on the electromagnetic waves emitted by the feed source according to the distance between itself and the feed source, so as to improve the gain of the reflected beam in the expected direction.

[0011] The array element includes a time-shifting structure and a phase-shifting structure, and an air gap is provided between the time-shifting structure and the phase-shifting structure.

[0012] The time-shifting structure includes at least one time-shifting unit;

[0013] The time-shifting unit includes a time-shifting dielectric substrate and upper and lower metal patches on its upper and lower surfaces; a ring of metal via array is provided on the time-shifting dielectric substrate to form a substrate integrated waveguide; a "well"-shaped gap is provided in the middle of the upper and lower metal patches, the "well"-shaped gap is composed of four rectangular gaps, and the two opposite rectangular gaps are parallel to each other and have the same size;

[0014] When there are two or more time-shifting cells, adjacent cells share a single metal patch;

[0015] By adjusting the size of the gap, the coupling between the multi-resonances is controlled, so as to adjust the time delay of the time delay unit, wherein the multi-resonances include the gap resonance of the upper and lower metal patches and the resonance of the substrate integrated waveguide, and the multi-resonances are equivalent to a filter, and the use of the filter (multi-resonance) as the time delay unit of the antenna is the core creation point of the application.

[0016] Further, the time delay compensation value of each array element in the transmission array antenna is Wherein, i,j represents the i-th row and j-th column array element, l ij is the distance of the electromagnetic wave to the array element, and c is the speed of light.

[0017] Further, the thickness of the air gap between the time delay structure and the phase shift structure is 0.45-0.5 times the working wavelength.

[0018] Further, the phase shift structure is realized by using a multi-layer FSS broadband transmission structure.

[0019] Further, the phase shift structure comprises a plurality of layers of phase shift medium substrates arranged from top to bottom, air gaps are arranged between each layer, and a metal patch unit is arranged on the upper surface of the phase shift medium substrate; the size of the metal patch unit is adjusted to obtain 360-degree phase shift.

[0020] Further, the metal patch unit comprises concentrically arranged outer square ring patches, middle square ring patches and inner square patches.

[0021] In the application, the coupling between the multi-resonances is controlled by adjusting the length and width of the time delay unit patch gap, wherein the multi-resonances include the resonances in the substrate integrated waveguide and the patch gap, the different resonance cavities are coupled, and can be equivalent to a spatial bandpass filter, which has bandpass performance and certain group delay characteristics, and the bandpass performance and time delay curve of the time delay unit are adjusted by adjusting the coupling cavity filter.

[0022] In the application, a larger time delay is obtained by cascading multiple time delay units, thereby meeting the requirement of different time delay values of different units of the array antenna.

[0023] In the application, the phase of the array antenna is adjusted by using an independent phase shift structure, thereby obtaining good beam pointing; the phase shift structure is a multi-layer broadband FSS, and the size of the metal patch on the dielectric substrate is adjusted to control the transmission phase, so that 360-degree phase scanning is achieved.

[0024] In the application, the time delay structure and the phase shift structure are independent of each other and are separated by about half a wavelength to avoid coupling affecting their respective performances.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] 1. The application uses time delay compensation technology, which can compensate for the time delay difference caused by the different spatial distances between the feed source and each unit of the array surface during narrow pulse transmission, thereby improving the gain of the planar transmission array antenna and reducing the distortion of the time domain signal.

[0027] 2. The application separates the time delay compensation structure from the phase shift structure, designs a time shift structure and a phase shift structure respectively, and sets a distance of about half a wavelength between the two structures, which are independent of each other and avoid affecting each other.

[0028] 3. The time shift structure used in the application has an expected profile of about 50mm, and the ratio of the profile thickness to the loaded microstrip time delay compensation line is 1:9, which can greatly reduce the profile height.

[0029] 4. Compared with the traditional parabolic antenna and phased array antenna, the application mainly uses a planar structure, which is easy to process, does not need to design complex TR components and phase shift networks, and is relatively simple to design. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a power comparison diagram of a planar array antenna without time delay compensation and a planar array antenna with time delay compensation.

[0031] Figure 2 It is a diagram of the actual effective area of a narrow pulse beam transmission array surface without time delay compensation over time.

[0032] Figure 3 It is a schematic diagram of the partition structure of the planar reflective array antenna according to the embodiment of the application.

[0033] Figure 4 It is a three-dimensional view of the transmission array unit according to the embodiment of the application.

[0034] Figure 5 It is a single-layer three-dimensional view of the transmission array time delay structure according to the embodiment of the application.

[0035] Figure 6 It is a double-layer three-dimensional view of the transmission array time delay structure according to the embodiment of the application.

[0036] Figure 7 It is a three-layer three-dimensional view of the transmission array time delay structure according to the embodiment of the application.

[0037] Figure 8 It is a four-layer three-dimensional view of the transmission array time delay structure according to the embodiment of the application.

[0038] Figure 9 It is a three-dimensional view of the transmission array phase shift structure according to the embodiment of the application.

[0039] Figure 10Time delay unit time delay value diagram for different embodiments of the present application.

[0040] Figure 11 Top layer key parameter diagram of the time delay structure for embodiments of the present application.

[0041] Figure 12 Middle layer key parameter diagram of the time delay structure for embodiments of the present application.

[0042] Figure 13 Patch specific parameter diagram of the phase shift structure for embodiments of the present application.

[0043] Figure 14 Phase change curve diagram of the phase shift structure with patch size change for embodiments of the present application.

[0044] Legend: 1. feed horn antenna, 2. planar transmissive array antenna, 3. time delay structure, 31. upper layer metal patch, 32. time shift dielectric substrate, 33. lower layer metal patch, 34. "well" type slot, 35. metal via, 4. phase shift structure, 41. phase shift dielectric substrate, 42. outer layer square ring patch, 43. middle layer square ring patch, 44. inner layer square patch. DETAILED DESCRIPTION

[0045] The technical solutions of the present application are described in further detail below in combination with the drawings and specific embodiments. It should be noted that the specific embodiments given below are implemented under the premise of the technical solutions of the present application, and are only used to better explain and illustrate the present application, and do not limit the present application.

[0046] The present embodiment provides a narrow pulse time delay compensation type planar transmissive array antenna, as shown in Figure 3 The antenna includes a transmissive array antenna and a feed antenna.

[0047] The feed antenna is a horn antenna and provides excitation for the transmissive array antenna in a forward feeding manner.

[0048] The transmissive array antenna is a planar transmissive array antenna composed of a plurality of array elements. Each array element performs corresponding time delay compensation on the electromagnetic wave emitted by the feed according to the distance between the array element and the feed, so as to improve the gain of the reflected beam in the intended direction.

[0049] As shown in Figure 4 The array element includes a time shift structure and a phase shift structure, and an air gap with a thickness of 0.45 to 0.5 times the wavelength is arranged between the time shift structure and the phase shift structure.

[0050] The planar transmissive array antenna is processed in zones, and different zones correspond to different time delay compensation values. The time delay compensation value calculation method of each array element is: wherein, i,j represent the array element in the i-th row and j-th column, l ij Let c be the distance the electromagnetic wave travels to the array element, and c be the speed of light.

[0051] Based on the required delay compensation value, basic time-shifting units are cascaded to obtain different delay compensation values.

[0052] The time-shifting structure, such as Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown, it includes at least one time-shifting unit; the time-shifting unit includes a time-shifting dielectric substrate and upper and lower metal patches on its upper and lower surfaces, with adjacent units sharing a single metal patch; a ring of metal vias is disposed on the time-shifting dielectric substrate to form a substrate integrated waveguide; a grid-shaped slot is disposed in the middle of the upper and lower metal patches, the grid-shaped slot being composed of four rectangular slots, with two opposite rectangular slots being parallel to each other and having the same size. The time-shifting dielectric substrate has a side length of 17 mm and a thickness of 0.787 mm, and the material used is Robots 3003; by adjusting the size of the grid-shaped slot, the coupling between multiple resonances can be controlled, thereby adjusting the time delay of the time-shifting unit; the metal cylinder of the substrate integrated waveguide has a radius of 0.4 mm, a center distance of 0.8 mm from the edge of the dielectric substrate, and a periodic distance of 1.5 mm between the metal cylinders.

[0053] The phase-shifting structure, such as Figure 9 As shown, a multilayer FSS broadband transmission structure is used, which has relatively stable time delay characteristics of about 0.5 ns, thus it can assist the time delay structure in phase modulation. Specifically, the phase-shifting structure includes five phase-shifting dielectric substrates arranged sequentially from top to bottom, with an air gap of 7 mm thickness between each layer. An outer square annular patch, a middle square annular patch, and an inner square patch are concentrically arranged on the upper surface of the phase-shifting dielectric substrate. The phase-shifting dielectric substrate has a side length of 17 mm and a thickness of 0.9 mm, and the dielectric material used is Rogers 5880 with a relative permittivity of 2.2. 360-degree phase modulation is achieved by adjusting the size of the metal patch units.

[0054] There is an air gap of 0.45 to 0.55 times the wavelength between the phase-shifting structure and the time-shifting structure to avoid mutual coupling and affecting performance.

[0055] In this embodiment, by adjusting the number of layers and key dimensional parameters of the time delay structure, and thus the coupling coefficient of the resonator, the desired time delay compensation value can be obtained. It is worth noting that, due to the symmetry of the structure, the gap dimensions of the top and bottom layers of the time delay structure are the same, and the key parameters are as follows: Figure 10 As shown; the gap size parameters of each layer in the middle are the same, and the key parameters andFigure 11 The phase shift structure is shown in Fig. 2.

[0056] The key parameters of the phase shift structure are shown in Table 1. Figure 12 As shown in Fig. 3, the size of the transformation c can realize 360° scanning of the phase, and the phase change is related to the size of c. Figure 13 The phase shift structure is shown in Fig. 2.

[0057] The planar transmission array antenna partitioning method integrates the regions with similar required time delay values of the array region, and uses a time shift structure, thereby reducing the design and processing costs.

[0058] In this embodiment, the distance between the feed source and the center of the transmission array surface is 0.55m, the distance from the transmission array surface to the edge is 1.3m, and the array surface radius is 1.178m.

[0059] In this embodiment, the maximum time delay compensation is 2.5ns, and the time delay results of different units are shown in Fig. 4. Figure 14 Taking 0.5ns as the reference, the array surface is partitioned, and the array surface partition size data can be obtained by calculation. The smaller the time delay compensation value required by the unit closer to the edge of the array surface is. Calculation can obtain that the 0-433mm part of the array surface radius is region I; the 433-648mm part is region II; the 648-835mm part is region III; the 835-1010mm part is region IV; and the 1010-1178mm part is region V.

[0060] The key parameters of the time delay structure and the phase shift structure of different partitions and the time delay values are shown in Table 1. It is worth noting that since the phase shift unit has a basic 0.5ns time delay, region V will not use time delay compensation structure, and directly using the phase shift structure can complete the time delay compensation.

[0061] Different regions correspond to different time delay values, and the final time delay control and phase control are combined to obtain the expected high-gain beam.

[0062] Table 1 Key parameters of time delay structure and phase shift structure of different regions

[0063]

[0064] The above description is only used to describe the present application, and the present application is not limited by the above embodiments. Improvements, equivalent replacements and the like made by those skilled in the art according to the present application all belong to the protection scope of the present application.

Claims

1. A narrow pulse delay-compensated planar transmission array antenna, the antenna comprising a transmission array antenna and a feed antenna; The feed antenna provides excitation to the transmission array antenna using either a positive feed or an offset feed method. The transmission array antenna is composed of several array elements; characterized in that Each element in the transmission array antenna performs corresponding time delay compensation on the electromagnetic waves emitted by the feed source according to the distance between itself and the feed source, so as to improve the gain of the transmission beam in the expected direction. The array element includes a time-shifting structure and a phase-shifting structure arranged from top to bottom, and an air gap is provided between the time-shifting structure and the phase-shifting structure; The phase-shifting structure is implemented using a multi-layer FSS broadband transmission structure; The time-shifting structure includes at least one time-shifting unit; The time-shifting unit includes a time-shifting dielectric substrate and upper and lower metal patches on its upper and lower surfaces; a ring of metal via array is provided on the time-shifting dielectric substrate to form a substrate integrated waveguide; a "well"-shaped gap is provided in the middle of the upper and lower metal patches, the "well"-shaped gap is composed of four rectangular gaps, and the two opposite rectangular gaps are parallel to each other and have the same size; When there are two or more time-shifting cells, adjacent cells share a single metal patch; By adjusting the gap size, the coupling between multiple resonators is controlled, thereby adjusting the time delay of the time-shifting unit.

2. A narrow pulse time delay compensated planar transmitarray antenna according to claim 1, characterized in that, The time delay compensation value of each array element in the transmission array antenna is wherein, i,j represents the array element of the i-th row and the j-th column, l ij is the distance of the electromagnetic wave reaching the array element, and c is the speed of light.

3. A narrow pulse time delay compensated planar transmitarray antenna according to claim 2, characterized in that, The thickness of the air gap between the time-shifting structure and the phase-shifting structure ranges from 0.45 to 0.5 times the operating wavelength.

4. A narrow pulse time delay compensated planar transmitarray antenna as claimed in claim 3, characterized in that, The phase-shifting structure includes several layers of phase-shifting dielectric substrates arranged sequentially from top to bottom, with air gaps between each layer, and metal patch units disposed on the upper surface of the phase-shifting dielectric substrates; by adjusting the size of the metal patch units, 360-degree phase shifting can be achieved.

5. A narrow pulse time delay compensated planar transmitarray antenna as claimed in claim 4, characterized in that, The metal patch unit includes an outer square annular patch, a middle square annular patch, and an inner square patch arranged concentrically.

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