A multi-octave phased array design method based on a heterogeneous antenna combination

Abstract

The application provides a multi-octave phased array design method based on a heterogeneous antenna combination, which comprises the following steps: step 1, constructing a high-frequency array; step 2, constructing a medium-frequency array; step 3, constructing a low-frequency array; step 4, constructing a multi-stage subarray synthesis switch network, or configuring an AD / DA module after each array element channel in a full-channel digital array manner, so that the sampled data after discretization is digitally beam synthesized according to the equivalent array element relationship; and step 5, configuring corresponding working frequency band components according to the antenna type, and configuring AD / DA modules according to the subarray output of each frequency band. The method improves the gain utilization rate of the system in the multi-octave working frequency band, reduces the number of hardware channels without reducing the effective radiation power and sensitivity, compresses the equipment cost, meets the balance between the array gain and the number of channels of the system, and changes the characteristic that the efficiency of a single antenna at low frequency is always lower than that at high frequency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of active phased array systems, in particular to a multi-octave phased array design method based on heterogeneous antenna combination. BACKGROUND

[0002] With the continuous development of microwave technology, the application demand of the working frequency range covered by the phased array radio frequency device is expanding. In order to ensure that there is no grating lobe in the beam scanning range of the system, the element spacing in the phased array is often less than 1 / 2 of the wavelength of the highest working frequency point of the device. Under this constraint, the aperture of the single-channel element antenna is small, and the antenna gain of the element is low and the channel efficiency is poor when working at low frequency. At this time, in order to ensure the receiving sensitivity and effective transmitting power of the device at low frequency, a large size of the total array aperture must be constructed with small elements, which causes the number of total channels to increase sharply, and the manufacturing and maintenance costs to increase accordingly, which seriously affects the cost-effective ratio of the device production.

[0003] How to balance the indicators and costs through the combination of heterogeneous antennas has become the key and difficulty of the design of the current comprehensive radio frequency system in the multi-octave application scenario. SUMMARY

[0004] The present application provides a multi-octave phased array design method based on heterogeneous antenna combination, which can be used to solve the technical problem that heterogeneous antennas are difficult to balance indicators and costs.

[0005] The present application provides a multi-octave phased array design method based on heterogeneous antenna combination, as shown in Figure 1 The method comprises the following steps:

[0006] Step 1, constructing a high-frequency array;

[0007] Step 2, constructing a medium-frequency array;

[0008] Step 3, constructing a low-frequency array;

[0009] Step 4, constructing a multi-stage subarray synthesis switch network, or configuring an AD / DA module after each element channel in the full-channel digital array mode. At this time, there is no need to construct a network switch, and the discretized sampling data is digitally beam synthesized according to the equivalent element relationship as needed;

[0010] Step 5, configuring the corresponding working frequency band components according to the antenna type, and configuring the AD / DA module according to the subarray output of each frequency band.

[0011] Further, step 1, constructing a high-frequency array, comprises:

[0012] The required coverage range of the working frequency band of the array plane is (f1, f2), wherein f1 = f2 / K, K is a frequency multiplication multiple (usually > 10), and the corresponding wavelengths are λ1 = Kc / f2 and λ2 = c / f2, respectively, c is the speed of light. According to the scanning range requirement of f2 and the array plane, the aperture size of the high-frequency array element is h x w, wherein h is the length and w is the width, and the larger value of h and w does not exceed λ2 / 2; the high-frequency array element will pass through all the working frequency points [f2 / K, f2] of the frequency multiplication, and adopts a wideband tightly coupled antenna form, the profile height is constrained by f2 / K, and the gain g0(f2) of the high-frequency array element at f2 is:

[0013]

[0014] The number of high-frequency array elements is calculated according to the effective radiation power ERP(f2) required by the system at f2, wherein the single-channel power is p0, and the number of rows x the number of columns is a, then:

[0015]

[0016] The high-frequency array plane is shown in Figure 1 .

[0017] Further, step 2, constructing a medium-frequency array plane, comprising:

[0018] The size of each medium-frequency array element is N times the size of the high-frequency array element in the two-dimensional direction, respectively; N is a positive integer and is less than or equal to 3; that is, the size of the medium-frequency array element is Nh x Nw; wherein Nh is the length and Nw is the width; the profile height is the same as that of the high-frequency array element;

[0019] Due to the expansion of the size of the medium-frequency array element, grating lobes will be generated at a frequency point higher than f2 / N, so the working frequency band range of the medium-frequency array element is [f2 / K, f2 / N], and the gain g1(f2 / N) of the high-frequency array element at f2 / N is:

[0020]

[0021] The gain of the high-frequency array element and the medium-frequency array element at the respective working frequency point boundary is the same; when the system works in (f2 / N, f2], the system only opens the relevant channel of the high-frequency array element, and when the working frequency point ≤ f2 / N enters the working interval of the medium-frequency array element, the high-frequency array element and the medium-frequency array element are opened at the same time and are synthesized;

[0022] In order to ensure the beam synthesis effect, every N x N high-frequency array element needs to form an equivalent replacement with the medium-frequency array element in aperture aperture power and phase compensation;

[0023] Suppose the single-channel power of the medium-frequency array element is p1, and the power satisfies:

[0024] N 2 p0N2 g0(f) = p1g1(f)

[0025]

[0026] So p1 = N 2 p0, the sum of the power of the single channel and the equivalent number of high frequency array elements is the same, that is, the aperture power density p0 / (hw) is the same for different size antenna elements, where p0 is the single channel power and hw is the array element aperture area;

[0027] Because the operating bandwidth of the intermediate frequency array element is narrower and the component efficiency is higher, the energy consumption of the intermediate frequency array element channel is less under the premise of maintaining the same power output. In terms of phase compensation, the feed position of each intermediate frequency array element is converted into N×N high frequency array element feed positions, and the phase compensation value at each position is calculated according to the length of the perpendicular segment projected from the feed point to the vertical plane passing through the equivalent intermediate frequency array element reference feed point and having the beam pointing direction as the normal, as shown in Figure 2 ;

[0028] The number of intermediate frequency array elements is calculated according to the effective radiated power ERP(f2 / N) required by the system at f2 / N, where the single channel power is p0, and the number of rows and columns is i and j, respectively, so that:

[0029]

[0030] In order to ensure that the two kinds of heterogeneous antennas can complete two-dimensional splicing, it should be a / N≤i, b / N≤j, and i, j, a / N and b / N are all integers; Because the high frequency array participates in beam synthesis, the number of array elements of the intermediate frequency array is ij-1. The schematic diagram of the intermediate frequency array is shown in Figure 1 ;

[0031] Further, step 3, constructing a low frequency array, comprising:

[0032] The size of each low frequency array element is M times the size of the intermediate frequency array element in the two-dimensional direction, respectively; M is a positive integer and is less than or equal to 3; that is, the size of the intermediate frequency array element is MNh×MNw; MNh is the length, and MNw is the width, and the cross-sectional height is the same as that of the high frequency array element; Because the size of the low frequency array element is expanded, grating lobes will be generated at a frequency point greater than f2 / MN, so the operating frequency range of the intermediate frequency array element is [f2 / K, f2 / MN], and at this time the gain g2(f2 / MN) of the high frequency array element at f2 / MN is:

[0033]

[0034] The high frequency, intermediate frequency and low frequency array elements have the same gain at the respective operating frequency points;

[0035] When the system works in (f2 / MN, f2 / N], the system only guarantees to open the relevant channels of high and medium frequency array elements, and when the working frequency ≤f2 / MN enters the low frequency array element working interval, the high frequency array element and the medium frequency array element are opened at the same time and synthesized;

[0036] In order to ensure the beam synthesis effect, every MxM medium frequency array element needs to form an equivalent replacement with the low frequency array element in aperture aperture power and phase compensation; the single channel power of the medium frequency array element is p1, which satisfies:

[0037] M 2 p1M 2 g1(f)=p2g2(f)

[0038]

[0039] Therefore, p2=M 2 p1=M 2 N 2 p0, also in accordance with the same power density principle of p=p0 / (hw); since the working bandwidth of the low frequency array element is narrower and the component efficiency is higher, the energy consumption of the low frequency array element channel is less under the premise of maintaining the same power output. In terms of phase compensation, the feeding position of each low frequency array element is converted into the feeding position of MxM high frequency array elements, and the phase compensation value at each place is calculated according to the length of the vertical segment projected by the feeding point to the vertical plane passing through the equivalent low frequency array element reference feeding point and perpendicular to the beam pointing direction, as shown in Figure 2 ;

[0040] The number of low frequency array elements is calculated according to the effective radiated power ERP(f2 / MN) required by the system at f2 / MN, wherein the single channel power is p0, and contains r rowsx s columns, then:

[0041]

[0042] In order to ensure that the three kinds of heterogeneous antennas can complete two-dimensional splicing, there should be i / M≤r, j / N≤s, and r, s, i / M, j / M are all integers; since the medium and high frequency array surfaces participate in beam synthesis, the number of array elements of the low frequency array surface is rs-1. The schematic diagram of the low frequency array surface is shown in Figure 1 ;

[0043] Further, an AD / DA module is configured after each array element channel in the full channel digital array manner; the discretized sampling data is digitally beam synthesized according to the equivalent array element relationship as needed, including:

[0044] Step 4-a, a multi-stage subarray synthesis switch network is constructed, as shown in Figure 3 ;

[0045] The phased array needs to realize digital sampling and back-end digital beam synthesis (DBF) and other signal processing procedures according to the subarray. In the common way of dividing the subarray according to the column, the channel types and quantities involved in each column of the heterogeneous array surface are respectively synthesized and led out of the subarray output port according to the frequency band;

[0046] The contents contained in the "column" under different frequency bands are not necessarily the same, and the more heterogeneous antenna types contained, the more complex the network. For the frequency points in the range of (f2 / N, f2], the system only needs to start the high-frequency array element part, and the subarray is composed of a high-frequency array element a in the column after phase modulation, and there are b subarray output taps;

[0047] For frequency points in the range of (f2 / MN, f2 / N], the system starts the high and medium frequency band elements as needed. At this time, the subarray has three cases: the first case is completely composed of high-frequency array elements, each subarray contains iN 2 high-frequency array elements; the second case is that high-frequency array elements and medium-frequency array elements exist at the same time, and the output taps of the high-frequency subarray are borrowed; the third case is completely composed of medium-frequency array elements, each subarray contains i medium-frequency array elements;

[0048] For frequency points in the range of (f2 / K, f2 / MN], the system starts the high, medium and low frequency band elements as needed. At this time, the subarray has seven cases: the first case is completely composed of high-frequency array elements, each subarray contains rM 2 N 2 high-frequency array elements; the second case is that high-frequency array elements and medium-frequency array elements exist at the same time, and the output taps of the high-frequency subarray are borrowed; the third case is that high, medium and low frequency array elements exist at the same time, and the output taps of the high and medium frequency subarrays are borrowed; the fourth case is that high and low frequency array elements exist at the same time, and the output taps of the high frequency subarray are borrowed; the fifth case is completely composed of medium-frequency array elements, each subarray contains rM 2 high-frequency array elements; the sixth case is that medium and low frequency array elements exist at the same time, and the output taps of the medium frequency subarray are borrowed; the seventh case is completely composed of low-frequency array elements, each subarray contains r low-frequency array elements. The subarray synthesis diagram of high, medium and low frequency array elements participating at the same time is shown in Figure 3 .

[0049] Step 4-b: from Figure 3 It can be seen that the column subarray synthesis of the heterogeneous array surface is very complex, and combining the advantage of compressing the number of channels of the heterogeneous array surface, it is more suitable to adopt the full digital array system, that is, each single channel is a subarray, and AD / DA modules are configured for single channels of different frequency bands. The discrete sampling data is digitally beam synthesized DBF according to the equivalent array element relationship as needed.

[0050] The beneficial effects of the multi-octave phased array surface design method based on the heterogeneous antenna combination provided by the application are: by setting the aperture-matched antennas in the high, medium and low frequency bands, the gain utilization rate of the system is improved, and the characteristics that the efficiency of a single antenna at low frequency is always lower than that at high frequency are changed, providing more optimization space for the system, such as Figure 4 As shown in the figure, the number of hardware channels is reduced without reducing the effective radiation power and sensitivity, the equipment cost is greatly compressed, and the application scenario covering multiple octaves of working frequency bands is suitable. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 A two-dimensional splicing schematic diagram of heterogeneous array surfaces of different frequency bands is provided for the embodiments of the application.

[0052] Figure 2 A phase compensation schematic diagram of different array elements of a heterogeneous array surface is provided for the embodiments of the application.

[0053] Figure 3 A subarray synthesis schematic diagram in which high, medium and low frequency array elements of a heterogeneous array surface participate simultaneously is provided for the embodiments of the application.

[0054] Figure 4 The gain values of a heterogeneous array surface at different frequency bands are provided for the embodiments of the application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical scheme and advantages of the application more clear, the method provided by the application is specifically described below taking the system as an example, the working frequency band of the array surface is 2-18GHz (octave K=9), and the corresponding wavelengths are λ1=15cm and λ2=1.66cm. Two sizes of heterogeneous antennas are used for frequency band splicing:

[0056] Step 1, constructing a high frequency band array surface. According to the upper limit of the 18GHz working frequency point and the scanning range requirement of the array surface, the aperture size of the high frequency array element is determined to be 9mm*9mm. The high frequency array element will pass through all the working frequency points [2GHz, 18GHz] of the octave, at this time the gain of the high frequency array element at 18GHz is about 2.3dB. Assuming that the system high frequency single channel power is 10W, including 4 rows*4 columns, then the ERP of the high frequency array surface at the 18GHz frequency point is about 9.4kW;

[0057] Step 2, constructing a mid-frequency array surface. The size of each mid-frequency array element is 2 times the size of the high-frequency array element in the two-dimensional direction, i.e., the size of the mid-frequency array element is 18mm*18mm, and the profile height is the same as that of the high-frequency array element. The working frequency range of the mid-frequency array element is [2GHz, 9GHz]. When the system works in (9GHz, 18GHz], the system only opens the relevant channels of the high-frequency array element. When the working frequency point is less than or equal to 9GHz and enters the working interval of the mid-frequency array element, the high-frequency array element and the mid-frequency array element need to be opened at the same time and synthesized. In order to maintain the power density = 1.23*105W / m 2 , the single-channel power is 40W. The equivalent of the full array surface is to contain 3 rows*3 columns of mid-frequency array elements, so the ERP of the full array at 9GHz is about 11.8kW, which is greater than the ERP of the full array at 18GHz. The system full array contains 16 high-frequency array elements and 5 mid-frequency array elements, and the total number of array channels is 21. Compared with the traditional scheme of constructing 6 rows*6 columns of high-frequency array elements, the number of channels is reduced by 42%;

[0058] Step 3, since this example only constructs a heterogeneous antenna of mid and high frequency bands, this step does not need to be performed;

[0059] Step (4-a): constructing a multi-stage subarray synthesis switch network. For the frequency points in the range of (9GHz, 18GHz], the system only needs to open the high-frequency array element part, and its subarray is to extract 4 array elements in the high-frequency array surface by column, phase shift and synthesize an output tap of a subarray, and there are 4 output taps of subarrays; for the frequency points in the range of (2GHz, 9GHz], the system opens the high and mid frequency band array elements as needed, at this time, the subarray has two possibilities: ① the high-frequency array element and the mid-frequency array element exist at the same time, and 8 high-frequency array elements and 1 mid-frequency array element are needed to be used together for synthesis; ② the mid-frequency array element is completely phase-shifted and synthesized, and each subarray contains 3 mid-frequency array elements;

[0060] Step (4-b): using a full digital group design, configuring AD / DA modules for the 21 array element channels of the full scale array surface, and performing digital beam synthesis (DBF) on the discretized sampling data according to the equivalent array element relationship in step (4-a) as needed;

[0061] Step (5): configuring the corresponding working frequency band components according to the antenna type, and configuring the AD / DA modules according to the subarray output of each frequency band.

[0062] In summary, the above is only a preferred embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

[0063] The method improves the gain utilization rate of the whole system in the multiple octave working frequency band, significantly reduces the number of hardware channels without reducing the effective radiation power and sensitivity, greatly compresses the equipment cost, meets the balance between the array gain and the number of channels of the system, changes the characteristic that the efficiency of the single antenna is always lower at low frequency than at high frequency, and provides more optimization space for the system.

[0064] The above-described embodiments of the present application do not constitute a limitation of the protection scope of the present application.

Claims

1. A multi-octave phased array design method based on heterogeneous antenna combination, characterized in that, The method comprises: Step 1, constructing a high-frequency array surface; Step 2, constructing a medium-frequency array surface; Step 3, constructing a low-frequency array surface; Step 4, constructing a multi-stage subarray synthesis switch network, or configuring an AD / DA module after each array element channel in a full-channel digital array manner, then a network switch is not needed; the discretized sampling data is digitally beam synthesized according to the equivalent array element relationship as needed; Step 5, configuring corresponding working frequency band components according to the antenna type, and configuring AD / DA modules according to the subarray output of each frequency band; Constructing a high-frequency array surface comprises: The required coverage range of the working frequency band of the array surface is (f1, f2), wherein f1 = f2 / K, K is a frequency multiplication multiple, and K > 10, and the corresponding wavelengths are λ1 = Kc / f2 and λ2 = c / f2, c is the speed of light; the aperture size of the high-frequency array element is determined according to f2 and the scanning range requirement of the array surface, and is h x w, wherein h is the length and w is the width, and the larger one of h and w does not exceed λ2 / 2; the high-frequency array element penetrates all the working frequency points [f2 / K, f2] of the frequency multiplication, adopts a wideband tightly coupled antenna form, the profile height is constrained by f2 / K, and the gain g0(f2) of the high-frequency array element at f2 is: The number of high-frequency array elements is calculated according to the required effective radiated power ERP(f2) of the system at f2, wherein the single-channel power is p0, and a row x b columns are included, and there is: Step 2, constructing a medium-frequency array surface comprises: The size of each medium-frequency array element is N times of the high-frequency array element in the two-dimensional direction respectively; N is a positive integer and is less than or equal to 3; that is, the size of the medium-frequency array element is Nh x Nw; wherein Nh is the length and Nw is the width; the profile height is the same as that of the high-frequency array element; The working frequency band range of the medium-frequency array element is [f2 / K, f2 / N], and the gain g1(f2 / N) of the high-frequency array element at f2 / N is: The gain of the high-frequency array element and the medium-frequency array element at the respective working frequency point boundary is the same; when the system works in (f2 / N, f2], only the relevant channel of the high-frequency array element is turned on, and when the working frequency point ≤f2 / N enters the working interval of the medium-frequency array element, the high-frequency array element and the medium-frequency array element are turned on at the same time and are synthesized; In order to ensure the beam synthesis effect, every N x N high-frequency array elements need to form equivalent replacement on the aperture aperture power and phase compensation with respect to the medium-frequency array element; Suppose the single-channel power of the medium-frequency array element is p1, and the power satisfies: N 2 p0N 2 g0(f)=p1g1(f) So there p1 = N 2 p0, the intermediate frequency array element single channel power and the equivalent number of high frequency array element power sum, that is, in different size antenna array element aperture mouth power density p = p0 / (hw) is the same, wherein, p0 is single channel power, hw is array element aperture area; On the phase compensation, the feeding position of each medium-frequency array element is converted into the feeding position of N x N high-frequency array elements, and the phase compensation value at each place is calculated according to the length of the vertical segment projected from the feeding point to the vertical plane passing through the equivalent medium-frequency array element reference feeding point and perpendicular to the beam pointing direction; The number of medium-frequency array elements is calculated according to the required effective radiated power ERP(f2 / N) of the system at f2 / N, wherein the single-channel power is p0, and i rows x j columns are included, and there is: a / N ≤ i, b / N ≤ j, and i, j, a / N and b / N are all integers; since the high-frequency array surface participates in beam synthesis, the number of array elements of the medium-frequency array surface is ij-1; Step 3, constructing a low-frequency array surface comprises: The size of each low-frequency array element is M times of the size of the middle-frequency array element in two-dimensional direction respectively; M is a positive integer and is less than or equal to 3; that is, the size of the middle-frequency array element is MNh*MNw; MNh is the length, MNw is the width, the profile height is the same as that of the high-frequency array element; the working frequency range of the middle-frequency array element is [f2 / K, f2 / MN], at this time, the gain g2(f2 / MN) of the high-frequency array element at f2 / MN is: The high-frequency, middle-frequency and low-frequency array elements have the same gain at the boundary value of the respective working frequency points; When the system works in (f2 / MN, f2 / N], the system only guarantees to open the relevant channels of the high-frequency and middle-frequency array elements, when the working frequency point is less than or equal to f2 / MN, the low-frequency array element working interval is entered, the high-frequency array element and the middle-frequency array element are simultaneously opened and synthesized; In order to ensure the beam synthesis effect, every M*M middle-frequency array element needs to form an equivalent replacement in aperture aperture power and phase compensation with respect to the low-frequency array element; the single-channel power of the middle-frequency array element is p1, and the power satisfies: M 2 p1M 2 g1(f) = p2g2(f) So there p2 = M 2 p1 = M 2 N 2 p0, also meet the same power density principle of p = p0 / (hw); in phase compensation, the feed position of each low-frequency array element is converted into the feed position of MxM high-frequency array elements, and the phase compensation value at each position is calculated according to the length of the perpendicular segment projected by the feed point to the perpendicular of the vertical plane through the equivalent low-frequency array reference feed point. The number of low-frequency array elements is calculated according to the effective radiation power ERP(f2 / MN) required by the system at f2 / MN, wherein the single-channel power is p0, and contains r rows*s columns, so: There are i / M≤r, j / N≤s, and r, s, i / M and j / M are integers; since the middle and high-frequency array surfaces participate in beam synthesis, the number of array elements of the low-frequency array surface is rs-1.

2. The method of claim 1, wherein, A multi-stage subarray synthesis switch network is constructed, and an AD / DA module is configured after each array element channel in a full-channel digital array manner; the discretized sampling data is digitally beam synthesized according to the equivalent array element relationship; including: Step 4-a, constructing a multi-stage subarray synthesis switch network; The channel type and number involved in each column of the heterogeneous array surface are synthesized and led out of the subarray output port according to the frequency range; For the frequency points in the range of (f2 / N, f2], the system only needs to open the high-frequency array element part, and the subarray is a subarray output tap synthesized by adjusting the phase of a array element in the high-frequency array surface according to column extraction, and there are b subarray output taps; For the frequency range of (f2 / MN, f2 / N], the system opens high and medium frequency elements as needed, at this time the subarray exists in three cases: the first case is completely composed of high frequency elements, each subarray contains iN 2 high frequency elements; the second case is that high frequency elements and medium frequency elements exist at the same time, borrowing the output tap of the high frequency subarray; the third case is completely composed of medium frequency elements, each subarray contains i medium frequency elements; For the frequency points in the range of [f2 / K, f2 / MN], the system starts high, medium and low frequency array elements as needed, at this time there are 7 cases of sub-array: the first case is completely composed of high frequency array elements, each sub-array contains rM 2 N 2 high frequency array elements; the second case is that high frequency array elements and medium frequency array elements exist at the same time, and the output taps of high frequency sub-array need to be borrowed; the third case is that high, medium and low frequency array elements exist at the same time, and the output taps of high and medium frequency sub-array need to be borrowed; the fourth case is that high and low frequency array elements exist at the same time, and the output taps of high frequency sub-array need to be borrowed; the fifth case is completely composed of medium frequency array elements, each sub-array contains rM 2 medium frequency array elements; the sixth case is that medium and low frequency array elements exist at the same time, and the output taps of medium frequency sub-array need to be borrowed; the seventh case is completely composed of low frequency array elements, each sub-array contains r low frequency array elements; Step 4-b: a full-digital array system is adopted, that is, each single channel is a subarray, AD / DA modules are configured for single channels of different frequency ranges, and discretized sampling data is digitally beam synthesized DBF according to the equivalent array element relationship.

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