Multi-octave phased array plane design method based on heterogeneous antenna combination

Abstract

The invention provides a multi-octave phased array plane design method based on heterogeneous antenna combination. The multi-octave phased array plane design method comprises the following steps: step 1, constructing a high-frequency-band array plane; step 2, constructing a medium-frequency band array surface; 3, constructing a low-frequency-band array surface; 4, constructing a multi-stage subarray synthesis switch network, or configuring an AD / DA module behind each array element channel according to a full-channel digital array mode, and carrying out digital beam synthesis on discretized sampling data as required according to an equivalent array element relationship without constructing a network switch; and step 5, configuring a corresponding working frequency band assembly according to the type of the antenna, and configuring an AD / DA module according to the sub-array output of each frequency band. According to the method, the gain utilization rate of the whole system on the multi-octave working frequency band is improved, the number of hardware channels is reduced on the premise that the effective radiation power and sensitivity are not reduced, the equipment cost is reduced, the balance of the system between the array plane gain and the number of channels is met, and the system performance is improved. The characteristic that the efficiency of a single antenna at low frequency is always lower than that at high frequency is changed.

Description

Technical Field

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

[0002] With the continuous development of microwave technology, the application demand for the working frequency band covered by phased array RF equipment is constantly expanding. In order to ensure that the system does not have grating lobes within the beam scanning range, the array element spacing in the phased array often does not exceed 1 / 2 of the wavelength of the highest working frequency of the equipment. Under this constraint, the aperture of the single-channel array element antenna is small. When the array element works in the low frequency band, the antenna gain is low and the channel efficiency is poor. At this time, in order to ensure the receiving sensitivity and effective transmission power of the equipment in the low frequency band, a large-size total array aperture has to be constructed with smaller array elements, resulting in a sharp increase in the total number of channels in the system, and a corresponding increase in manufacturing and maintenance costs, which seriously affects the cost-effectiveness of equipment production.

[0003] How to achieve a balance between indicators and costs through the combination of heterogeneous antennas has become the key and difficulty in the design of current integrated RF systems in multi-octave application scenarios. Summary of the invention

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

[0005] The present application provides a multi-octave phased array design method based on heterogeneous antenna combination, such as Figure 1 As shown, the method includes:

[0006] Step 1, construct the high-frequency band array;

[0007] Step 2, construct the mid-frequency array;

[0008] Step 3, construct the low-frequency array;

[0009] Step 4: construct a multi-level sub-array synthesis switch network, or configure an AD / DA module after each array element channel in a full-channel digital array mode. In this case, there is no need to build a network switch, and the discretized sampled data is digitally beamformed as needed according to the equivalent array element relationship;

[0010] Step 5: Configure the corresponding working frequency band components according to the antenna type, and configure the AD / DA module according to the sub-array output of each frequency band.

[0011] Furthermore, step 1, constructing a high-frequency array, includes:

[0012] Assume that the coverage required by the array's operating frequency band is (f1, f2), where f1 = f2 / K, K is the octave multiple (usually > 10), and the corresponding wavelengths are λ1 = Kc / f2, λ2 = c / f2, and c is the speed of light. According to the requirements of f2 and the scanning range of the array, the aperture size of the high-frequency array element is determined to be h×w, where 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 run through all octave operating frequency points [f2 / K, f2], using a broadband 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 based on the effective radiated power ERP(f2) required by the system at f2, where the single-channel power is p0, containing a rows × b columns, then:

[0015]

[0016] The high frequency front diagram is as follows Figure 1 shown.

[0017] Furthermore, step 2, constructing a mid-frequency array, includes:

[0018] The size of each intermediate frequency array element is N times the high frequency array element in two-dimensional directions; N is a positive integer and less than or equal to 3; that is, the size of the intermediate frequency array element is Nh×Nw; Nh is the length and Nw is the width; the cross-sectional height is the same as that of the high frequency array element;

[0019] As the size of the intermediate frequency array element increases, grating lobes will be generated at frequencies higher than f2 / N, so the operating frequency band of the intermediate frequency array element is [f2 / K, f2 / N]. At this time, the gain g1(f2 / N) of the high frequency array element at f2 / N is:

[0020]

[0021] The high-frequency array element and the intermediate-frequency array element have the same gain at the upper limit of their respective working frequencies; when the system works at (f2 / N, f2], the system only turns on the relevant channels of the high-frequency array element. When the working frequency is ≤f2 / N and enters the working range of the intermediate-frequency array element, the high-frequency array element and the intermediate-frequency array element are turned on and synthesized at the same time;

[0022] In order to ensure the beamforming effect, each N×N high-frequency array element needs to be equivalent to the intermediate frequency array element in terms of aperture power and phase compensation;

[0023] Assume that the power of a single channel of the intermediate 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 single-channel power of the intermediate frequency array element is the same as the sum of the powers of the equivalent number of high-frequency array elements, that is, the aperture power density ρ=p0 / (hw) is the same for antenna elements of different sizes, where p0 is the single-channel power and hw is the aperture area of ​​the array element;

[0027] Since the working 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 feeding position of each intermediate frequency array element is converted into N×N high frequency array element feeding positions, and each phase compensation value is calculated based on the length of the vertical line segment projected from the feeding point to the vertical plane passing through the reference feeding point of the equivalent intermediate frequency array element with the beam pointing as the normal phase, such as Figure 2 As shown;

[0028] The number of IF array elements is calculated based on the effective radiated power ERP(f2 / N) required by the system at f2 / N, where the single channel power is p0, containing i rows × j columns, then:

[0029]

[0030] In order to ensure that the two heterogeneous antennas can complete two-dimensional splicing, a / N≤i, b / N≤j, and i, j, a / N and b / N are all integers; since 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 as follows Figure 1 As shown;

[0031] Furthermore, step 3, constructing a low-frequency array, includes:

[0032] The size of each low-frequency array element is M times the size of the intermediate-frequency array element in two-dimensional directions; 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, MNw is the width, and the cross-sectional height is the same as that of the high-frequency array element; due to the expansion of the size of the low-frequency array element, grating lobes will be generated at frequencies greater than f2 / MN, so the operating frequency band of the intermediate-frequency array element is [f2 / K, f2 / MN], and the gain g2(f2 / MN) of the high-frequency array element at f2 / MN is:

[0033]

[0034] The high-frequency, medium-frequency and low-frequency array elements have the same gain at the upper limit of their respective operating frequencies;

[0035] When the system works at (f2 / MN, f2 / N], the system only ensures that the relevant channels of the high- and medium-frequency array elements are turned on. When the working frequency is ≤f2 / MN and enters the working range of the low-frequency array element, the high-frequency array element and the medium-frequency array element are turned on and synthesized at the same time;

[0036] In order to ensure the beamforming effect, each M×M intermediate frequency array element needs to form an equivalent replacement for the low frequency array element in terms of aperture power and phase compensation. It is known that the single channel power of the intermediate frequency array element is p1, and the power satisfies:

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

[0038]

[0039] So p2=M 2 p1=M 2 N 2 p0, which also complies with the same power density principle of ρ = p0 / (hw); since the working bandwidth of the low-frequency array element is narrower and the component efficiency is higher, the low-frequency array element channel consumes less energy while maintaining the same power output. In terms of phase compensation, the feeding position of each low-frequency array element is converted into M×M high-frequency array element feeding positions, and each phase compensation value is calculated based on the length of the vertical line segment projected from the feeding point to the vertical plane passing through the reference feeding point of the equivalent low-frequency array element with the beam pointing as the normal phase, such as Figure 2 As shown;

[0040] The number of low-frequency array elements is calculated based on the effective radiated power ERP(f2 / MN) required by the system at f2 / MN, where the single-channel power is p0, containing r rows × s columns, then:

[0041]

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

[0043] Furthermore, an AD / DA module is configured behind each array element channel in a full-channel digital array manner; the discretized sampled data is digitally beamformed as needed according to the equivalent array element relationship, including:

[0044] Step 4-a, construct a multi-level sub-array synthesis switch network, such as Figure 3 As shown;

[0045] Phased arrays need to implement digital sampling and back-end digital beamforming (DBF) and other signal processing processes based on sub-arrays. In the common way of dividing sub-arrays by columns, the channel types and quantities involved in each column of the heterogeneous array are synthesized and led out to the sub-array output port according to the frequency band;

[0046] The contents of "columns" in different frequency bands are not necessarily the same. The more types of heterogeneous antennas are included, the more complex the network is. For the frequency points within the range of (f2 / N,f2], the system only needs to turn on the high-frequency array element part. The sub-array is to extract a array element in the high-frequency array plane by column and then phase-adjust to synthesize a sub-array output tap. There are a total of b sub-array output taps;

[0047] For frequencies within the range of (f2 / MN, f2 / N], the system turns on high- and mid-band array elements as needed. At this time, there are three sub-arrays: the first is completely synthesized by high-frequency array elements, and each sub-array contains iN 2 The second case is that the high-frequency array elements and the intermediate-frequency array elements exist at the same time, and the output taps of the high-frequency sub-array are borrowed; the third case is that it is completely synthesized by the intermediate-frequency array elements, and each sub-array contains i intermediate-frequency array elements;

[0048] For the frequency points within the range of (f2 / K, f2 / MN], the system turns on the high, medium and low frequency band array elements as needed. At this time, there are 7 sub-arrays: the first case is completely synthesized by high frequency array elements, and each sub-array contains rM 2 N 2 In the second case, the high-frequency array elements and the intermediate-frequency array elements exist at the same time, and the output taps of the high-frequency sub-array need to be borrowed; in the third case, the high-, intermediate-, and low-frequency array elements exist at the same time, and the output taps of the high- and intermediate-frequency sub-arrays need to be borrowed; in the fourth case, the high- and low-frequency array elements exist at the same time, and the output taps of the high-frequency sub-array need to be borrowed; in the fifth case, it is completely synthesized by the intermediate-frequency array elements, and each sub-array contains rM 2 The sixth case is that the mid- and low-frequency array elements exist at the same time, and the output tap of the mid-frequency sub-array needs to be borrowed; the seventh case is completely synthesized by low-frequency array elements, and each sub-array contains r low-frequency array elements. The schematic diagram of the sub-array synthesis in which high, mid- and low-frequency array elements participate at the same time is shown in Figure 3 shown.

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

[0050] The multi-octave phased array design method based on heterogeneous antenna combination proposed in the present invention has the following beneficial effects: by setting aperture-matched antennas in high, medium and low frequency bands respectively, the gain utilization rate of the whole system is improved, and at the same time, the characteristic that the efficiency of a single antenna at low frequency is always lower than that at high frequency is changed, giving the system more room for optimization, such as Figure 4 As shown in the figure, the number of hardware channels is reduced without reducing the effective radiated power and sensitivity, which greatly reduces the equipment cost and is suitable for application scenarios where the working frequency band covers multiple octaves. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of two-dimensional splicing of heterogeneous array antennas of different frequency bands provided in an embodiment of the present application;

[0052] Figure 2 A schematic diagram of phase compensation for different array elements in a heterogeneous array provided in an embodiment of the present application;

[0053] Figure 3 A schematic diagram of sub-array synthesis in which high, medium and low frequency array elements simultaneously participate in a heterogeneous array provided in an embodiment of the present application;

[0054] Figure 4 The gain values ​​of the heterogeneous array in different frequency bands provided in the embodiments of the present application. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of this application clearer, the following system is taken as an example to specifically explain the method provided by this application. It is assumed that the working frequency band of the array is 2 to 18 GHz (octave K = 9), and the corresponding wavelengths are λ1 = 15 cm and λ2 = 1.66 cm. Two sizes of heterogeneous antennas are used for frequency band splicing:

[0056] Step 1, construct the high-frequency array. According to the upper limit of the 18GHz operating frequency and the scanning range requirements of the array, the aperture size of the high-frequency array element is determined to be 9mm×9mm. The high-frequency array element will run through all octave operating frequencies [2GHz, 18GHz]. 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, the ERP of the high-frequency array at the 18GHz frequency is about 9.4kW;

[0057] Step 2, construct the mid-frequency array. The size of each mid-frequency array element is twice that of the high-frequency array element in two dimensions, that is, the size of the mid-frequency array element is 18mm×18mm, and the cross-sectional height is the same as that of the high-frequency array element. The operating frequency band of the mid-frequency array element is [2GHz, 9GHz]. When the system works at (9GHz, 18GHz], the system only turns on the relevant channels of the high-frequency array element. When the operating frequency point ≤9GHz enters the working range of the mid-frequency array element, the high-frequency array element and the mid-frequency array element need to be turned on and synthesized at the same time. In order to maintain the power density of the mid-frequency array element = 1.23×105W / m 2 , the single-channel power is 40W. The entire array is equivalent to 3 rows × 3 columns of intermediate frequency array elements, so the ERP of the entire array at 9GHz is about 11.8kW, which is greater than the ERP of the entire array at 18GHz. The entire array of the system includes 16 high-frequency array elements, 5 intermediate frequency array elements, and the total number of array channels is 21. Compared with the traditional solution of constructing 6 rows × 6 columns of high-frequency array elements, this design reduces the number of channels by 42%;

[0058] Step 3: Since this example only constructs heterogeneous antennas for medium and high frequency bands, this step is not required.

[0059] Step (4-a): Construct a multi-level subarray synthesis switch network. For frequencies within the range of (9GHz, 18GHz], the system only needs to turn on the high-frequency array element part. The subarray extracts 4 array elements in the high-frequency array plane by column and then phase-modulates them to synthesize a subarray output tap. There are a total of 4 subarray output taps; for frequencies within the range of (2GHz, 9GHz], the system turns on high- and medium-frequency array elements as needed. At this time, there are two possibilities for the subarray: ① High-frequency array elements and medium-frequency array elements exist at the same time, and 8 high-frequency array elements and 1 medium-frequency array element need to be borrowed to synthesize together; ② It is completely synthesized by phase modulation of medium-frequency array elements, and each subarray contains 3 medium-frequency array elements;

[0060] Step (4-b): Adopting a full digital group design, AD / DA modules are configured for each of the 21 array element channels of the full-scale array, and the discretized sampled data is subjected to digital beamforming (DBF) as needed according to the equivalent array element relationship in step (4-a);

[0061] Step (5): Configure the corresponding working frequency band components according to the antenna type, and configure the AD / DA module according to the sub-array output of each frequency band.

[0062] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0063] This method improves the gain utilization of the entire system in multi-octave operating frequency bands, significantly reduces the number of hardware channels without reducing effective radiated power and sensitivity, greatly compresses equipment costs, and satisfies the system's balance between array gain and number of channels. It also changes the characteristic that the efficiency of a single antenna at low frequencies is always lower than that at high frequencies, giving the system greater room for optimization.

[0064] The above-described embodiments of the present application do not constitute a limitation on 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, construct the high-frequency band array; Step 2, construct the mid-frequency array; Step 3, construct the low-frequency array; Step 4: construct a multi-level sub-array synthesis switch network, or configure an AD / DA module behind each array element channel in a full-channel digital array manner, without the need to construct a network switch; perform digital beam synthesis on demand for the discretized sampled data according to the equivalent array element relationship; Step 5: Configure the corresponding working frequency band components according to the antenna type, and configure the AD / DA module according to the sub-array output of each frequency band.

2. The method according to claim 1, characterized in that: Step 1: construct a high-frequency array; including: Assume that the coverage range required by the working frequency band of the array is (f1, f2), where f1 = f2 / K, K is the octave multiple, and K>10, and the corresponding wavelengths are λ1 = Kc / f2, λ2 = c / f2, and c is the speed of light; according to the requirements of f2 and the scanning range of the array, the aperture size of the high-frequency array element is determined to be h×w, where 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 run through all the working frequency points of the octave [f2 / K, f2], using a broadband 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 based on the effective radiated power ERP(f2) required by the system at f2, where the single-channel power is p0, containing a rows × b columns, then:

3. The method according to claim 1, characterized in that Step 2: Construct the mid-frequency array, including: The size of each intermediate frequency array element is N times the high frequency array element in two-dimensional directions; N is a positive integer and less than or equal to 3; that is, the size of the intermediate frequency array element is Nh×Nw; Nh is the length and Nw is the width; the cross-sectional height is the same as that of the high frequency array element; The operating frequency range of the intermediate frequency array element is [f2 / K, f2 / N]. At this time, the gain g1(f2 / N) of the high frequency array element at f2 / N is: The high-frequency array element and the intermediate-frequency array element have the same gain at the upper limit of their respective working frequencies; when the system works at (f2 / N, f2], the system only turns on the relevant channels of the high-frequency array element. When the working frequency is ≤f2 / N and enters the working range of the intermediate-frequency array element, the high-frequency array element and the intermediate-frequency array element are turned on and synthesized at the same time; In order to ensure the beamforming effect, each N×N high-frequency array element needs to be equivalent to the intermediate frequency array element in terms of aperture power and phase compensation; Assume that the power of a single channel of the intermediate frequency array element is p1, and the power satisfies: N 2 p0N 2 g0(f)=p1g1(f) So p1=N 2 p0, the single-channel power of the intermediate frequency array element is the same as the sum of the powers of the equivalent number of high-frequency array elements, that is, the aperture power density ρ=p0 / (hw) is the same for antenna elements of different sizes, where p0 is the single-channel power and hw is the aperture area of ​​the array element; In terms of phase compensation, the feeding position of each IF array element is converted into N×N HF array element feeding positions, and each phase compensation value is calculated based on the length of the vertical line segment projected from the feeding point to the vertical plane passing through the reference feeding point of the equivalent IF array element with the beam pointing as the normal phase; The number of IF array elements is calculated based on the effective radiated power ERP(f2 / N) required by the system at f2 / N, where the single channel power is p0, containing i rows × j columns, then: a / N≤i, b / N≤j, and i, j, a / N and b / N are all integers; since the high-frequency array participates in beam synthesis, the number of array elements of the intermediate-frequency array is ij-1.

4. The method according to claim 1, characterized in that: Step 3: construct the low-frequency array, including: The size of each low-frequency array element is M times the size of the intermediate-frequency array element in two-dimensional directions; 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, MNw is the width, and the cross-sectional height is the same as that of the high-frequency array element; the operating frequency band range of the intermediate-frequency array element is [f2 / K, f2 / MN], and the gain g2(f2 / MN) of the high-frequency array element at f2 / MN is: The high-frequency, medium-frequency and low-frequency array elements have the same gain at the upper limit of their respective operating frequencies; When the system works at (f2 / MN, f2 / N], the system only ensures that the relevant channels of the high- and medium-frequency array elements are turned on. When the working frequency is ≤f2 / MN and enters the working range of the low-frequency array element, the high-frequency array element and the medium-frequency array element are turned on and synthesized at the same time; In order to ensure the beamforming effect, each M×M intermediate frequency array element needs to form an equivalent replacement for the low frequency array element in terms of aperture power and phase compensation. It is known that the single channel power of the intermediate frequency array element is p1, and the power satisfies: M 2 p1M 2 g1(f)=p2g2(f) So p2=M 2 p1=M 2 N 2 p0, which also complies with the same power density principle of ρ=p0 / (hw); in terms of phase compensation, the feeding position of each low-frequency array element is converted into M×M high-frequency array element feeding positions, and each phase compensation value is calculated based on the length of the vertical line segment projected from the feeding point to the vertical plane passing through the reference feeding point of the equivalent low-frequency array element with the beam pointing as the normal phase; The number of low-frequency array elements is calculated based on the effective radiated power ERP(f2 / MN) required by the system at f2 / MN, where the single-channel power is p0, containing r rows × s columns, then: i / M≤r, j / N≤s, and r, s, i / M, j / M are all integers; since the medium and high frequency arrays participate in beam synthesis, the number of array elements of the low frequency array is rs-1.

5. The method according to claim 1, characterized in that Construct a multi-level sub-array synthesis switch network, configure AD / DA modules behind each array element channel in a full-channel digital array mode; perform digital beam synthesis on demand for the discretized sampled data according to the equivalent array element relationship; including: Step 4-a, constructing a multi-stage sub-array synthesis switch network; The channel types and quantities involved in each column of the heterogeneous array are synthesized according to the frequency band and led out to the sub-array output port; For the frequency points within the range of (f2 / N,f2], the system only needs to turn on the high-frequency array element part. The sub-array extracts a array elements in the high-frequency array plane by column and then phase-modulates them to form a sub-array output tap. There are a total of b sub-array output taps. For frequencies within the range of (f2 / MN, f2 / N], the system turns on high- and mid-band array elements as needed. At this time, there are three sub-arrays: the first is completely synthesized by high-frequency array elements, and each sub-array contains iN 2 The second case is that the high-frequency array elements and the intermediate-frequency array elements exist at the same time, and the output taps of the high-frequency sub-array are borrowed; the third case is that it is completely synthesized by the intermediate-frequency array elements, and each sub-array contains i intermediate-frequency array elements; For the frequency points within the range of (f2 / K, f2 / MN], the system turns on the high, medium and low frequency band array elements as needed. At this time, there are 7 sub-arrays: the first case is completely synthesized by high frequency array elements, and each sub-array contains rM 2 N 2 In the second case, the high-frequency array elements and the intermediate-frequency array elements exist at the same time, and the output taps of the high-frequency sub-array need to be borrowed; in the third case, the high-, intermediate-, and low-frequency array elements exist at the same time, and the output taps of the high- and intermediate-frequency sub-arrays need to be borrowed; in the fourth case, the high- and low-frequency array elements exist at the same time, and the output taps of the high-frequency sub-array need to be borrowed; in the fifth case, it is completely synthesized by the intermediate-frequency array elements, and each sub-array contains rM 2 The sixth case is that the mid- and low-frequency array elements exist at the same time, and it is necessary to borrow the output taps of the mid-frequency sub-array; the seventh case is completely synthesized by phase modulation of low-frequency array elements, and each sub-array contains r low-frequency array elements. Step 4-b: Adopt a fully digital array system, that is, each single channel is a sub-array, configure AD / DA modules for single channels of different frequency bands, and perform digital beamforming DBF on the discretized sampling data as needed according to the equivalent array element relationship.

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