Narrow pulse time delay compensation plane transmission array antenna

Abstract

The invention provides a narrow pulse time delay compensation type plane transmission array antenna, and belongs to the technical field of antennas. The antenna comprises a transmission array antenna and a feed source antenna. Each array element in the transmission array antenna performs 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 reflection wave beam in an expected direction; the array element comprises a time shifting structure and a phase shifting structure, and in the time shifting structure, the time delay amount of the time shifting structure is adjusted by adjusting the gap size and controlling coupling among multiple resonances. Through the time delay compensation technology, the time delay difference caused by different spatial distances between the feed source and each unit of the array plane in the narrow pulse transmission process is compensated, so that the gain of the plane transmission array antenna is improved, and the distortion of a time domain signal is reduced; the profile height is small, the processing is easy, and the design is simple and convenient.

Description

Technical Field

[0001] The present invention belongs to the technical field of antennas, and particularly relates to a narrow pulse time-delay compensation planar transmissive array antenna. Background Art

[0002] With the rapid development of modern communication technologies, antennas, as "converters" for receiving and transmitting electromagnetic waves, which are important information carriers, are of self-evident importance. In radar systems, aerospace satellites, etc., high-gain antennas are more favored. Parabolic antennas and phased array antennas are often selected as antenna types that can meet the above characteristics. A parabolic antenna consists of a parabolic reflecting surface and a feed source, and usually has high gain, strong anti-interference ability and directivity. However, parabolic antennas usually require large sizes, the body is heavy, and its special parabolic surface has high requirements for processing accuracy. Phased array antennas require a large number of phase shifters, and the feeding network is complex, reducing the efficiency of the antenna and increasing the design difficulty of the antenna. Planar array antennas can effectively solve the above problems and integrate the advantages of parabolic antennas and phased array antennas.

[0003] High Power Microwave (HPM) refers to microwave radiation with a frequency between several hundred megahertz and several tens of gigahertz and an output power between several megawatts and several thousand megawatts, and is commonly used in the fields of military and national defense security. The typical waveform of high power microwave is a narrow pulse. When a large-aperture planar reflector antenna receives and transmits a narrow pulse wave, the performance of the antenna will be affected due to insufficient compensation for the unit time-delay ability. Figure 1 The power diagrams of a planar array antenna without time-delay compensation and with time-delay compensation when transmitting a narrow pulse wave are shown and compared. A pulse beam with a 5 ns rising edge and falling edge and a 2 ns peak is used. It can be seen that the received power of the antenna without time-delay compensation has changed compared with the antenna with time-delay compensation ability. Specifically, the pulse beam is stretched, the rising edge and the falling edge become slower, and the peak time becomes shorter. It can be seen that the peak power of the antenna with time-delay compensation has increased by about 3 dB compared with the peak of the antenna without time-delay compensation. As Figure 2 shown is the equivalent illumination unit of the antenna array surface irradiated by a simulated horn transmitting a narrow pulse beam changing with time. It can be clearly seen that at different times, the antenna cannot be fully illuminated, so that the units on the array surface cannot play their roles simultaneously, thereby reducing the antenna gain.

[0004] Therefore, it is of great significance to explore the time-delay compensation technology for planar arrays under narrow pulse waves. In the existing technologies, the common time-delay compensation method is to directly couple microstrip lines for linear time adjustment. However, this method has the problem that when the required time-delay compensation is large, the length of the microstrip line is long. For example, when the radius of the array surface is 1.37 m and the distance between the feed horn and the center of the array surface is 0.6 m, the maximum time-delay compensation required for the array surface at this time is 3 ns, and the corresponding length of the microstrip line is 0.45 m. Obviously, the length is too long, which will make the profile too high and difficult to install and process. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technologies, the present invention proposes a narrow pulse time-delay compensation type planar transmission array antenna. The present invention can effectively realize the time-delay compensation of the electromagnetic waves fed into the planar transmission antenna array while ensuring the profile height of the antenna.

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

[0007] A narrow pulse time-delay compensation type planar transmission array antenna, which includes a transmission array antenna and a feed antenna;

[0008] The feed antenna provides excitation for the transmission array antenna in a front-feed manner;

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

[0010] It is characterized in that each array element in the transmission array antenna performs corresponding time-delay compensation on the electromagnetic waves emitted by the feed according to the distance between it and the feed, so as to improve the gain of the reflected beam in the expected direction;

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

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

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

[0014] When there are more than two time-delay units, adjacent units share a metal patch;

[0015] By adjusting the gap size, the coupling between multiple resonances is controlled, thereby adjusting the time delay of the time-delay unit. Among them, the multiple resonances include the gap resonance of the upper and lower metal patches and the resonance of the substrate integrated waveguide. The multiple resonances are equivalent to a filter. Using the filter (multiple resonances) as the time-delay unit of the antenna is the core creative point of the present invention.

[0016] Furthermore, the time delay compensation value of each element in the transmissive array antenna is where i, j represent the element in the i-th row and j-th column, and l ij is the distance that the electromagnetic wave reaches this element, and c is the speed of light.

[0017] Furthermore, the thickness value range of the air gap between the time-delay structure and the phase-shift structure is 0.45 to 0.5 times the operating wavelength.

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

[0019] Furthermore, the phase-shift structure includes several layers of phase-shift dielectric substrates arranged in sequence from top to bottom. An air gap is provided between each layer, and metal patch units are provided on the upper surface of the phase-shift dielectric substrate; by adjusting the size of the metal patch units, 360-degree phase modulation is obtained.

[0020] Furthermore, the metal patch unit includes an outer square ring-shaped patch, a middle square ring-shaped patch, and an inner square patch that are concentrically arranged.

[0021] In the present invention, the coupling between multiple resonances is controlled by adjusting the length and width of the patch gap of the time-delay unit. Among them, the multiple resonances include the resonance in the substrate integrated waveguide and the patch gap. The coupling of different resonators can be equivalent to a spatial band-pass filter, which has band-pass performance and certain group delay characteristics. The band-pass performance and time-delay curve of the time-delay unit are adjusted by adjusting the method of the coupled cavity filter.

[0022] In the present invention, a larger time delay is obtained by cascading multiple time-delay units, thereby meeting the requirements of different time delay values required by different units of the array antenna.

[0023] In the present invention, the array antenna is phase-modulated by using an independent phase-shift structure, and thus a good beam pointing is obtained; the phase-shift structure is a multi-layer broadband FSS, and the transmission phase is controlled by adjusting the size of the metal patches on the dielectric substrate to achieve 360-degree phase scanning.

[0024] In the present invention, the time-delay structure and the phase-shift structure are independent of each other, and there is an interval of about half a wavelength to avoid coupling from affecting their respective performances.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] 1. The present invention uses a time delay compensation technique, 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 the transmission of narrow pulses, thereby improving the gain of the planar transmission array antenna and reducing the distortion of the time-domain signal.

[0027] 2. The present invention separates the time delay compensation structure from the phase shift structure, designs a time shift structure and a phase shift structure respectively, and there is a distance of about half a wavelength between the two, which are independent of each other and avoid mutual influence.

[0028] 3. The expected profile of the time shift structure adopted by the structure of the present invention is about 50 mm, and the ratio of the profile thickness of the time delay compensation line loaded with microstrip to the profile thickness of the time shift structure is 1:9, which can greatly reduce the profile height.

[0029] 4. Compared with the traditional parabolic antenna and phased array antenna, the present invention mainly uses a planar structure, which is easy to process, does not require the design of complex TR components and phase shift networks, and the design is relatively simple. Description of the Drawings

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

[0031] Figure 2 It is a diagram of the actual effective area irradiated by the 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 reflection array antenna described in the embodiment of the present invention.

[0033] Figure 4 It is a three-dimensional perspective view of the transmission array unit described in the embodiment of the present invention.

[0034] Figure 5 It is a three-dimensional perspective view of a single layer of the time delay structure of the transmission array described in the embodiment of the present invention.

[0035] Figure 6 It is a three-dimensional perspective view of a double layer of the time delay structure of the transmission array described in the embodiment of the present invention.

[0036] Figure 7 It is a three-dimensional perspective view of a triple layer of the time delay structure of the transmission array described in the embodiment of the present invention.

[0037] Figure 8 It is a three-dimensional perspective view of a quadruple layer of the time delay structure of the transmission array described in the embodiment of the present invention.

[0038] Figure 9 It is a three-dimensional perspective view of the phase shift structure of the transmission array described in the embodiment of the present invention.

[0039] Figure 10Schematic diagram of time delay values of different time delay units in the embodiments of the present invention.

[0040] Figure 11 Top - level key parameter diagram of the time delay structure in the embodiments of the present invention.

[0041] Figure 12 Middle - level key parameter diagram of the time delay structure in the embodiments of the present invention.

[0042] Figure 13 Specific parameter diagram of the patch of the phase - shifting structure in the embodiments of the present invention.

[0043] Figure 14 Curve graph of the phase - modulation phase varying with the patch size in the embodiments of the present invention.

[0044] Explanation of reference numerals: 1. Feed horn antenna, 2. Planar transmission array antenna, 3. Time delay structure, 31. Upper - layer metal patch, 32. Time - shifting dielectric substrate, 33. Lower - layer metal patch, 34. "Well" - shaped slit, 35. Metal through - hole, 4. Phase - shifting structure, 41. Phase - shifting dielectric substrate, 42. Outer - layer square - ring patch, 43. Middle - layer square - ring patch, 44. Inner - layer square patch. Detailed implementation manners

[0045] The following combines the drawings and specific embodiments to further describe the technical solutions of the present invention in detail. It should be noted that the following specific embodiments are implemented on the premise of the technical solutions of the present invention, and are only used to better explain and illustrate the present invention, rather than to limit the present invention.

[0046] This embodiment provides a narrow - pulse time - delay compensation type planar transmission array antenna. As Figure 3 shown, the antenna includes a transmission array antenna and a feed antenna.

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

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

[0049] The array element, as Figure 4 shown, includes a time - shifting structure and a phase - shifting structure, and there is an air gap with a thickness of 0.45 to 0.5 times the wavelength between the time - shifting structure and the phase - shifting structure.

[0050] The planar transmission array antenna is divided into different areas, and different areas correspond to different time - delay compensation values. The calculation method of the time - delay compensation value of each array element is: Among them, The elements at the i-th row and j-th column are represented by i and j, and l ij is the distance that the electromagnetic wave reaches the element, and c is the speed of light.

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

[0052] The time-delay structure, such as Figure 5 , Figure 6 , Figure 7 and Figure 8 shown, includes at least one time-delay unit; the time-delay unit includes a time-delay dielectric substrate, an upper-layer metal patch and a lower-layer metal patch on its upper and lower surfaces, and adjacent units share a metal patch; a circle of metal via arrays is arranged on the time-delay dielectric substrate to form a substrate integrated waveguide; "well"-shaped slits are arranged in the middle of the upper-layer metal patch and the lower-layer metal patch, and the "well"-shaped slits are composed of four rectangular slits, and the two opposite rectangular slits are parallel to each other and have the same size. The side length of the time-delay dielectric substrate is 17 mm, the thickness is 0.787 mm, and the material used is Rogers 3003; by adjusting the size of the "well"-shaped slits, the coupling between multiple resonances is controlled, so that the time-delay amount of the time-delay unit can be adjusted; the radius of the metal cylinder of the substrate integrated waveguide is 0.4 mm, the center of the circle is 0.8 mm away from the edge of the dielectric substrate, and the periodic distance between the metal cylinders is 1.5 mm.

[0053] The phase-shifting structure, such as Figure 9 shown, is realized by a multi-layer FSS broadband transmission structure, and its time-delay characteristic is relatively stable, about 0.5 ns, so it can assist the time-delay structure to perform phase adjustment. Specifically, the phase-shifting structure includes 5 layers of phase-shifting dielectric substrates arranged in sequence from top to bottom, with an air gap with a thickness of 7 mm between each layer, and an outer-layer square ring patch, a middle-layer square ring patch, and an inner-layer square patch concentrically arranged on the upper surface of the phase-shifting dielectric substrate. The side length of the phase-shifting dielectric substrate is 17 mm, the thickness is 0.9 mm, the dielectric material used is Rogers 5880, and the relative dielectric constant is 2.2. By adjusting the size of the metal patch unit, 360-degree phase adjustment can be obtained.

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

[0055] In this embodiment, by adjusting the number of layers and key dimension parameters of the time-delay structure, the coupling coefficient of the resonator is further adjusted, and finally the required time-delay compensation value can be obtained. It should be noted that due to the symmetry of the structure, the slit dimension parameters of the top layer and the bottom layer of the time-delay structure are the same, and the key parameters are as Figure 10 shown; the slit dimension parameters of the middle layers are the same, and the key parameters andFigure 11 as shown

[0056] The key parameters of the phase shift structure are as Figure 12 shown. By changing the magnitude of c, 360° scanning of the phase can be achieved. The relationship between the phase change and the magnitude of c is as Figure 13 shown

[0057] The method for partitioning the planar transmissive array antenna is to integrate the areas with similar required time delay values on the array surface region and use the same time delay structure together, thereby reducing the design and manufacturing costs

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

[0059] In this embodiment, the maximum time delay compensation amount is 2.5 ns. The time delay results of different units are as Figure 14 shown. Taking 0.5 ns as the benchmark, the array surface is partitioned. From the formula calculation, the data of the array surface partition size can be obtained. The smaller the time delay compensation value required for the unit closer to the edge of the array surface. It can be calculated that the part with a radius of 0 - 433 mm of the array surface is Region I; the part with a radius of 433 - 648 mm is Region II; the part with a radius of 648 - 835 mm is Region III; the part with a radius of 835 - 1010 mm is Region IV; the part with a radius of 1010 - 1178 mm is Region V

[0060] The key parameters and time delay values of the time delay structure and phase shift structure in different partitions are shown in Table 1. It should be noted that since the phase shift unit has a basic time delay of 0.5 ns, the time delay compensation structure will not be used in Region V, and the time delay compensation can be completed directly using the phase shift structure

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

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

[0063]

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

Claims

1. A narrow pulse delay compensation type planar transmission array antenna, the antenna comprising a transmission array antenna and a feed antenna; The feed antenna provides excitation for the transmission array antenna by using a forward feed or a bias feed method; The transmission array antenna is composed of a plurality of array elements; It is characterized in that Each array element in the transmission 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, so as to improve the gain of the transmission beam in the expected direction; The array element comprises 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; The time-shifting structure comprises at least one time-shifting unit; The time-shifting unit comprises a time-shifting dielectric substrate and an upper metal patch and a lower metal patch on its upper and lower surfaces; a circle of metal through-hole arrays is arranged on the time-shifting dielectric substrate to form a substrate integrated waveguide; a "well"-shaped gap is arranged in the middle of the upper metal patch and the lower metal patch, and the "well"-shaped gap is composed of four rectangular gaps, and two opposite rectangular gaps are parallel to each other and have the same size; When there are more than two time-shifting units, adjacent units share a metal patch; By adjusting the gap size, the coupling between the multiple resonances is controlled, thereby adjusting the delay of the time shift unit.

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

3. A narrow pulse delay compensation planar transmission array antenna as claimed in 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 working wavelength.

4. A narrow pulse delay compensation planar transmission array antenna as claimed in claim 3, characterized in that: The phase shifting structure is realized by adopting a multi-layer FSS broadband transmission structure.

5. A narrow pulse delay compensation planar transmission array antenna as claimed in claim 4, characterized in that: The phase shift structure comprises several layers of phase shift dielectric substrates arranged sequentially from top to bottom, with air gaps between each layer, and metal patch units arranged on the upper surface of the phase shift dielectric substrate; 360-degree phase modulation is achieved by adjusting the size of the metal patch units.

6. A narrow pulse delay compensation planar transmission array antenna as claimed in claim 5, characterized in that: The metal patch unit comprises an outer square ring patch, a middle square ring patch and an inner square patch which are arranged concentrically.

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