JPH0454708A - Active phased array antenna system - Google Patents

Abstract

PURPOSE:To simplify the structure, to decrease the scale, to reduce the cost and to make the weight light by shaping a received beam in either an elevating angle direction or an azimuth direction through analog synthesis and shaping the beam in the other direction through digital synthesis. CONSTITUTION:The amplitude and phase of outputs of each radiation elements 111-11M are controlled respectively by transmission reception modules 211-21M properly and they are synthesized by an analog power synthesizer 711. Similarly other synthesizers 721-7N1 synthesizes outputs of modules 221-2NM to shape the beam on a Z-X plane. An output signal of each of the synthesizers 721-7N1 is detected and frequency-converted by receivers 821-8N1 converted into a digital signal by A/D converters 921-9N1 and the signal is inputted to a digital beam shaping circuit 101. Since the received beam in the X-axis direction through analog synthesis and the received beam in the Y-axis direction through digital synthesis in this way, the structure is comparatively made simple, the cost is reduced and the weight is made light.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an active phased array antenna device.

(Prior art) Conventional active phased array antenna devices that form multiple beams include an analog synthesis method that performs analog synthesis of the outputs of each radiating element of a planar array antenna, as well as an analog synthesis method that performs analog synthesis of the outputs of each radiating element. There is a digital beam forming (hereinafter abbreviated as DBF) method in which a signal is frequency-converted and then converted into a digital signal for processing.

FIG. 6 shows the configuration of a DBF type active face array antenna device, in which 1.1 to INM are radiating elements arranged in M pieces in the X-axis direction and N pieces in the Y-axis direction.

Each radiating element 11. ~INM are coupled to transmitter/receiver modules 211~2NM configured as shown in FIG. 7, respectively, and form a planar array antenna formed on the XY plane. In FIG. 7, 1 is a radiating element, 2 is a transmitting/receiving module, a is a transmitting system, and b is a receiving system. Furthermore, a is phase shifter a1 and HPA (high power amplifier) a
2 and b are provided with active elements such as an LNA (low noise amplifier) bl and a phase shifter b2.

The transmission signal output from the transmission exciter 3 is divided into N by the first analog power divider 4, and then supplied to the second analog power divider 5, ~5N, where it is divided into M in the vertical direction. The signal is sent to the radiating element coupled thereto via the transmitting system a of the arranged transmitting/receiving modules. In addition, each radiating element 1
11~INM output is the corresponding transmitting/receiving module 2m,
~2NM receiving system, A/D (analog/digital) converters 6.1~6NM convert the signals into digital signals, and each vertical output is sent to first digital beam forming circuits 71~7.
N, where N digital beams are formed, and then synthesized and outputted by a second digital beam forming circuit 8.

Digital beam forming circuit 7. ~7N (8 also has the same configuration) is generally constructed as shown in FIG. 8th
The figure shows 71 as a representative, and the radiating elements 1, 1 to 71 are shown as representatives.
As mentioned above, the output of 1□M is sent from the transmitter/receiver module 20~
21M, the frequency is converted by A/D converter 6. t~61M
After the signal is converted into a digital signal, it is input to the digital beam forming circuit 7I. This digital beam forming circuit 7,
Then, each input signal is sequentially delayed by delay elements C1 to cM having different delay times and sent to the calculation cells d1 to dM. Each of the calculation cells d8 to dM is supplied with a complex weight W, to WM according to the beam forming direction, respectively. As shown in Fig. 9, the arithmetic cell is composed of a multiplier e1 and an adder e2 and performs a simple product-sum operation.The element power X is multiplied by a complex weight W, and the signal Y from the adjacent cell is The sum is added to obtain the output Yl. That is, the calculation cells d1 to dM
are connected in a systolic array, thereby making it possible to obtain multi-beam output from all directions.

However, in an active phased array antenna device that adopts the DBF method with the above configuration, when performing DBF on a planar array antenna in which radiating elements are arranged two-dimensionally, all outputs of each radiating element are subjected to frequency conversion, A/ In order to perform D conversion and form a beam through digital processing, it is necessary to provide a frequency converter and an A/D converter for each element, as well as a large number of digital signal lines and arithmetic cells for beam formation. As a result, the structure becomes complex and large-scale, and as the number of elements increases, the weight increases.
This will lead to an increase in costs.

In contrast to such a BF method, an active phased array antenna device using a normal planar array that performs beam formation by analog synthesis in two dimensions is structurally simple, but the bits of the phase shifter built in the transmitter/receiver module Due to the limitation of the number (usually 3 to 6 bits), the receiving beam quality such as antenna side lobes is inferior to that of the DBF method.

Furthermore, the reception beam quality does not need to be high in all two dimensions; it is often sufficient to have good quality in either the elevation direction or the azimuth direction, depending on the purpose.

(Problems to be Solved by the Invention) As described above, in the conventional active phased array antenna device, the DBF method using a surface array antenna has a large structure and is not suitable for cost reduction and weight reduction. There is a limit to antenna performance in the combination method. Furthermore, the antenna reception beam does not necessarily have to be of high quality over two dimensions; it is often sufficient to improve the quality in only one dimension depending on the purpose.

This invention was made focusing on the above points, and is an active phased array that has a relatively simple structure, is small in scale, is suitable for low cost and weight reduction, and has good quality in the target direction dimension of the receiving beam. The purpose is to provide an antenna device.

[Configuration of the Invention (Means for Solving the Problems) To achieve the above object, an active phased array antenna device according to the present invention includes (1) a plurality of radiating elements arranged respectively in the elevation direction and the azimuth direction; , a plurality of active elements coupled to each of these radiating elements and controlling the phase of the output of the radiating element, and a radiating element arranged to direct the outputs of the plurality of active elements in either the elevation direction or the azimuth direction. A plurality of analog synthesizing means inputs each signal and synthesizes analog signals to form a receiving beam, and after inputting and converting each receiving beam output of the plurality of analog synthesizing means into digital signals, a digital beam in the other direction is generated. The first feature is that it is equipped with a digital beam forming means for forming the beam, and (2) a plurality of radiating elements arranged respectively in the elevation direction and the azimuth direction, and the output of each of these radiating elements is distributed to a plurality of systems. a plurality of active elements that are provided corresponding to each system output from the distribution means and control the phase of the output; and a plurality of active elements that direct the output of the plurality of active elements in either the elevation direction or the azimuth direction. A plurality of analog synthesizing means for forming a receiving beam by inputting the distributed outputs of the radiating elements arranged in the direction of and a plurality of digital beam forming means for forming a plurality of digital beams by converting each into a digital signal and then forming a plurality of digital beams in the other direction, (3) an arbitrary shape; a plurality of radiating elements disposed in the radiating elements; a plurality of active elements coupled to each of the radiating elements to control the phase of the radiating element output; and a subarray formed by dividing the arrangement shape of the radiating elements into a plurality of regions. , a plurality of analog synthesizing means for analog synthesizing the active element outputs of each subarray to form a receiving beam, and a digital beam forming method after inputting the receiving beam outputs of the plurality of analog synthesizing means and converting them into digital signals respectively. A third feature is that the apparatus includes a digital beam forming means for performing.

(Function) In the active phased array antenna device having the configuration described in the first feature, a receiving beam is formed by analog synthesis in either the elevation direction or the azimuth direction and by digital beam forming in the other direction. , the structure is simplified and the scale is reduced to make it suitable for lower cost and weight reduction, and the quality of the target direction dimension of the receiving beam is improved.

In the antenna device having the second characteristic configuration, the radiating element output is divided into multiple systems, and the analog synthesis,
Perform digital beamforming to form multiple beams.

In the antenna device having the third feature, an array antenna in which radiating elements are arranged in an arbitrary shape is divided into a plurality of subarrays, and each subarray is subjected to the above analog synthesis and digital beam forming to produce a multi-beam beam. form.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. However, in FIG. 1, the same parts as in FIG. 5 are denoted by the same reference numerals, and the different parts will be explained here.

FIG. 1 shows its configuration, and the transmission system is exactly the same as that in FIG. 5. In the receiving system, the transmitting/receiving modules 2□1 to 28M are connected to the LNA as shown in part 2 of FIG.
The output of b2.b is divided into two systems, and each distributed signal is sent to a phase shifter b2. It is designed to be output via b3. The first element output #1 and the second element output #2 of each module 21, ~2NM are respectively provided corresponding to the X-axis direction, and the analog power combiner 7□1~7N11712~ has a complex weight W1 set in advance. After being combined into N systems by 7N2, receivers 8.1 to 8 provided for each system
It is detected and frequency converted by N++81□ to 8N2. Further, each receiver 8.1 to 8.1, 8. The output of □~8N2 is sent to the A/D converter 91. ~9 Nll 9 +2~9
The #1 system is beam-formed by the first digital beam forming circuit 10□, and the #2 system is beam-formed by the second digital beam forming circuit 102.

The operation of the above configuration will be described below with reference to FIGS. 3 and 4.

Figure 3 shows radiation elements 111 to 11M arranged in the X-axis direction.
The series of element output #1 of one of the transmitter/receiver modules 2.1 to 21M is extracted and shown for each radiating element 1.
1. The outputs X1 to XM of ~1 and □ are respectively subjected to appropriate amplitude control and phase control by the transmitter/receiver module 2□1 to 2, and are then preliminarily converted to the complex fate W as the first element output #1.
1 is set in the analog power combiner 7.1. Similarly, other analog power combiners 721 to 7N+ are used in modules 22. By combining the outputs of ~22M, . . . , 2N1 to 2NM, a beam in the z-X plane is formed.

Here, the received signal supplied to each analog power combiner 711 to 7N+ is Xl, and the output signal is Yl(i-1...N
), then Y becomes Y, -Σ(Xl·W,)(i-1...N).

Further, as shown in FIG. 4, these N output signals Yt
is detected and frequency converted by the receivers 811 to 8N+,
The signal is converted into a digital signal by A/D converters 9□I to 9prr and input to the digital beam forming circuit 101. This digital beam forming circuit 10□ has the same configuration as the circuit shown in FIG. 8, and is constructed by connecting the arithmetic cells shown in FIG. 9 in a systolic array.

This digital beam forming circuit 10 includes arithmetic cells d, -
A complex calculation is performed by setting a complex weight W, (i-1...N) to dN. Output Y ou of each calculation cell d1 to dN
If the digital signal from the A/D converter is Xln and the digital signal from the adjacent cell is Yl-1, t becomes Yout -Yl-+W+*Xin. When these are arranged in a systolic array as shown in FIG. 8, the products of the antenna element signals Xin and the complex weights W are added while being timed by the delay elements c1 to cN, and the digital beam output #1. becomes. The above is exactly the same for #2 system.

Therefore, in the active phased array antenna device having the above configuration, the receiving beam in the X-axis direction is formed by analog synthesis, and the receiving beam in the Y-axis direction is formed by DBF, so the structure is relatively simple and the scale is small. It is suitable for cost reduction and weight reduction, and can provide a high quality receiving beam in the Y-axis direction.

Note that although the above embodiment is a case where DBF is performed in the Y direction in a planar array antenna, it goes without saying that the same function can be achieved even if, for example, the X-axis direction and the Y-axis direction are exchanged. Further, the present invention is applicable even when the radiating elements are arranged in an arbitrary shape such as a cylindrical shape. Moreover, although the case where a transmitting/receiving module is used is shown here, it goes without saying that similar effects can be obtained when only a phase shifter is used instead of the transmitting/receiving module.

Furthermore, the present invention is applicable not only to multi-beam antennas but also to single-beam forming antennas as shown in FIG. 5, for example. In FIG. 5, the same parts as in FIG. 1 are given the same reference numerals, and their explanations will be omitted. This configuration is obtained by removing the #2 system from the configuration shown in FIG. 1, and the other configurations are exactly the same.

Furthermore, for array antennas in which multiple radiating elements are arranged in an arbitrary shape, subarrays are formed by dividing the radiating element arrangement shape into multiple regions, and the active element outputs of each subarray are analog-combined to provide multiple reception channels. A similar effect can be obtained by forming a beam, converting the outputs of the plurality of received beams into digital signals, and then performing digital beam forming.

[Effects of the Invention] As described above, the present invention provides an active array antenna that has a relatively simple structure, is small in scale, is suitable for low cost and weight reduction, and has good quality in the target direction dimension of the receiving beam. equipment can be provided.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of an active phased array antenna device according to the present invention, FIG. 2 is a perspective view showing the configuration of a transmitting/receiving module of the same embodiment, and FIGS. 3 and 4 are respective embodiments of the same embodiment. 5 is a perspective view showing another embodiment according to the present invention, and FIG. 6 is a diagram for explaining the operation of the conventional active phased array antenna device.
7 is a perspective view showing the configuration of the transmitting/receiving module of the conventional device shown in FIG. 6; FIG. 8 is a block circuit diagram showing the configuration of the digital beam forming circuit of the conventional device; FIG. 9 is a perspective view showing the configuration of the BF system; This figure shows the configuration of an arithmetic cell used in the circuit of FIG. 8. 1.1~1□...radiating element, 2□1~2NM...transmission/reception module, a...transmission system, b...reception system, a
l...phase shifter, a2...HPASb,...LNA
, 3... Transmission exciter, 4... First analog power divider, 5, ~5N... Second analog power divider, 6
□1~6N&1...A/D converter, 7,~7N...
First digital beam forming circuit, 8... Second digital beam forming circuit, c1-cM... Delay element, d1-
dM...Arithmetic cell, W1-WM...Complex weight,
el...multiplier, e2...adder, k)2+ b
3... Phase shifter, #1... First element output, #2...
Second element output, #11...First beam output, #21...
...Second beam output, 71. ~7N1°7.2~7N2
...Analog power synthesizer, 811-8N+...Receiver, 911-9N+...A/D converter, 10.・・・
- First digital beam forming circuit, 10□... second digital beam forming circuit. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 113 Figure #11 Beam Yariki Figure 7 Figure 5 Figure 1M Figure 8 i Figure 9

Claims (2)

[Claims] (1) A plurality of radiating elements arranged in the elevation direction and an azimuth direction, a plurality of active elements coupled to each of these radiating elements and controlling the phase of the radiating element output, and an output of the plurality of active elements. a plurality of analog combining means for forming a receiving beam by analog combining inputs for each of the radiating elements arranged in either the elevation direction or the azimuth direction; and each receiving beam output of the plurality of analog combining means. an active phased array antenna device comprising digital beam forming means for inputting and converting each into a digital signal and then forming a digital beam in the other direction. (2) a plurality of radiating elements arranged respectively in the elevation direction and the azimuth direction, a distribution means for distributing the output of each of these radiating elements to a plurality of systems, and provided corresponding to the output of each system by the distribution means, A plurality of active elements that control the phase of the output, and the outputs of the plurality of active elements are inputted for each distributed output of the radiating element arranged in either the elevation direction or the azimuth direction, and are analog-synthesized. A plurality of analog combining means form a receiving beam using a plurality of analog combining means, and each receiving beam output of the plurality of analog combining means is input to each system and converted into a digital signal, and then digital beam forming in the other direction is performed. An active phased array antenna device comprising: a plurality of digital beam forming means forming a plurality of digital beams. (3) A plurality of radiating elements arranged in an arbitrary shape, a plurality of active elements coupled to each of these radiating elements to control the phase of the radiating element output, and dividing the arrangement shape of the radiating elements into a plurality of regions. a plurality of analog synthesis means for forming a reception beam by analog synthesis of the active element outputs of each subarray, and inputting each reception beam output of the plurality of analog synthesis means and converting each into a digital signal. an active phased array antenna device comprising: digital beam forming means for performing digital beam forming after performing digital beam forming;