JPH05218722A - Array antenna system - Google Patents

Abstract

PURPOSE:To obtain a digital beam output while number of channels of the array antenna system is reduced. CONSTITUTION:An output of an antenna element corresponding to an active region among antenna elements 11-KM is selected by switch circuits 111-11M, the output is frequency-converted by frequency converters 121-12M as a channel, the output is converted into a digital signal by A/D converters 131-13M and beam outputs 1, 2 are obtained by digital beam shaping circuits 141, 142.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an array antenna device.

[0002]

2. Description of the Related Art Conventionally, as a method of switching the active area of an array antenna apparatus to an arbitrary position, for example, the output of each antenna element arranged on the circumference is used as a channel, and after frequency conversion and conversion into a digital signal, Digital beam forming (hereinafter referred to as DBF) by selecting an arbitrary channel and forming an active area
There is a method to do. In the case of the DBF method, a frequency converter and an analog / digital converter corresponding to the number of antenna elements are required, and the circuit scale becomes large. On the other hand, there is a system in which only an analog circuit is used.

FIG. 5 shows an analog array antenna device. In FIG. 5, 11 to KM are antenna element groups in which an antenna element array in which M antenna elements are arranged, for example, K in a circle are arranged. The outputs of the antenna elements 11 to KM of the plurality of antenna element rows are output to the switch circuit 111.
It is distributed to ~ 11M. That is, the output of the first antenna element K1 in each area is input to the switch circuit 111, the output of the second antenna element K2 is input to the switch circuit 112, and thereafter the output of the Mth antenna element KM is the same. It is input to the switch circuit 11M.

The switch circuits 111 to 11M switch the allocated antenna element output to form an active area in an arbitrary direction. The outputs of the switch circuits 111 to 11M are rearranged in order so that an active area is formed correctly by a transfer switch matrix 101 composed of transfer switches, and then a phase shifter 102 and an analog combiner 103 are used to output a beam. Are formed.

In the case of this analog system, a transfer switch matrix is required, which complicates the circuit configuration and lowers the level of the antenna element output, resulting in deterioration of the beam output quality.

[0006]

As described above, when the active area of the array antenna device is switched to an arbitrary position, all the antenna elements are used as channels for the DBF.
, The frequency converter for the number of channels and analog /
Since a digital converter is required, the circuit scale of the entire device is large and the cost is high.

Therefore, the present invention has been made to solve the above-mentioned problems, and suppresses the enlargement of the circuit scale and the increase in cost that occur when performing the DBF with all the antenna element outputs as channels, and only the analog circuit is provided. SUMMARY OF THE INVENTION It is an object of the present invention to provide an array antenna device which prevents the circuit configuration from becoming complicated and the beam output quality from deteriorating when beam formation is performed by the above configuration.

[0008]

SUMMARY OF THE INVENTION According to the present invention, an antenna element group having a plurality of antenna elements and at least two antenna element outputs of the plurality of antenna elements are respectively supplied and predetermined for setting an active area. A plurality of selecting means for selecting respective antenna element outputs, a plurality of signal converting means for converting the outputs of the plurality of selecting means directly or after frequency conversion into digital signals, and a plurality of signal output of the plurality of signal converting means. The digital beam forming means for forming a beam by controlling the amplitude and phase of each signal after rearranging the order into a sequence corresponding to the active area is provided.

[0009]

According to the above means, the DBF is not performed by using all the antenna element outputs as the channels, but the active area is formed in any direction by using the selecting means, and only the antenna element outputs in the active area are used as the channels. Since the DBF is performed, the number of channels of the DBF becomes the same as the number of selecting means, and can be considerably reduced compared with the number of antenna elements. Also, by rearranging the digital signals or multiple weight signals corresponding to the output of the antenna element, D
Since the beam is formed by the BF, the transfer switch matrix is not necessary and the desired beam output can be obtained.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an array antenna device according to the present invention. However, the same parts as those in FIG.
The different parts will be described below.

Each antenna element 1 of the plurality of antenna element rows
The outputs of 1 to KM are distributed to the switch circuits 111 to 11M. Therefore, these switch circuits 111 to 11
By operating M, an active region is formed in any direction. The outputs of the switch circuits 111 to 11M are
Analog or digital (hereinafter referred to as A / D) directly or after frequency conversion by the frequency converters 121 to 12M, respectively.
Are converted into digital signals by the converters 131 to 13M, and the DBFs are converted by the digital beam formers 141 and 142.
Beam output is obtained. Of course, if n digital beam formers are provided, then n beam outputs can be obtained at the same time. The digital beam formers 141 and 142 will be described below with reference to FIG.

FIG. 2 (a) shows the structure, which is A /
Digital outputs Y _{1 to} Y _{M of} D converters 131 to 13 _M
Is input to the digital switch matrix d1.
The outputs X _{1 to} X _M have delay elements d11 to d1M, multipliers d21 to d2M, and an adder d3, which sequentially have different delay times.
The following operation is performed by 2～D3M, whereby bi - beam output XOUT _i is obtained. XOUT _i = Σ (W _i · X _i exp (jΦ)) (i = 1 to
M) W _i ; amplitude, phase weight (complex weight)

FIG. 2B is a diagram for explaining the operation of the digital switch matrix d1. For example, the active area of the device is shown in FIG.
Set within the range of 1) to 2 (M-2). This setting is performed by operating the switch circuits 111 to 11M. The outputs of the switch circuits 111 to 11M are frequency converters 121 to 12M and A / D converter 131, respectively, as channels.
Through 13 _M to become digital outputs Y _{1 to} Y _M.

The outputs of the antenna elements 1 (M-1), 1M, 21, ... 2 (M-2) forming the active area are digital outputs Y _M-1 , Y _M , Y ₁ , respectively.
... It corresponds to Y _M-2 . Therefore, the A / D converter 13
Y _M-1 the sequence of digital output Y ₁ to Y _M of _{1~13M, Y M, Y 1,} ... unless it is impossible to correctly perform the DBF is corrected to Y _M-2. Therefore, the digital switch matrix d1 using the active area information set from the outside, performs reordering of the digital output Y ₁ to Y _M.

[0015] Incidentally, in FIG. 2 (a), the digital output Y _M-1 is the _{reordering, Y M, Y 1, ...} Y M-2 respectively X
It is represented as _{1 to} X _M. The value of the complex weight W _i is
This is a fixed value that is read from a read memory (hereinafter referred to as ROM) d4 in which information on the beam scanning direction and desired excitation weight is set. FIG. 3 is a diagram for explaining another embodiment of the digital beam formers 141, 142.

FIG. 3 (a) shows the structure, and FIG.
The difference from the configuration of (a) is that the digital switch matrix d1 is not provided, and the same portions are denoted by the same reference numerals and the description thereof is omitted. A / D converters 131 to 1
The 3M digital outputs Y _{1 to} Y _M are the delay elements d 11 to
It is input to the multipliers d21 to d2M via d1M.

FIG. 3 (b) is a diagram for explaining the operation of the configuration shown in FIG. 3 (a). Here, the digital output Y ₁
The reordering of to Y _M in order to perform equalization, the digital output _{Y 1, Y 2, Y 3} , ... Y M-2, Y M-1, Y M complex weight W ₃ corresponding to the order of, _{w 4, W 5, ... W} M, W
It is multiplied by ₁ and W ₂ . The value of the complex weight W _i is
The active area information for correcting the order of the complex weights W _i is read from the ROM d4 together with the information on the scanning direction and the desired excitation weight.

That is, the method shown in FIG.
The order of the digital outputs Y _{1 to} Y _M of the D converters 131 to 13 _M is defined as the antenna elements 1 forming the active area.
In order to correspond to the order of (M-1), 1M, 21, ... 2 (M-2), the hardware configuration is such that order correction is performed by the digital switch matrix d1, and the method shown in FIG. This is a software configuration for performing order correction of the weight W _i .

In both configurations, not only the peak of the beam is formed in the boresight direction of the active region, but also the phase of the complex weight W _i of each channel is controlled to perform the beam scanning. You can

Although the above embodiment has been described by taking a one-dimensional array antenna device as an example, it is needless to say that the present invention can be applied to a planar array antenna device and an array antenna device having an arbitrary shape.

As shown in FIG. 4, each antenna element 1
N antenna elements 11 ¹ provided for ¹ to KM
~ KM ^N It is also applicable to the case where the output of the above is analog-synthesized by the analog synthesizing circuits 211 to 2KM to form a sub-array, and thereafter the beam is formed in the same manner as in FIG. 4, the same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In this configuration, the operation after the analog synthesizing circuits 211 to 2KM is exactly the same as that in FIG.

[0022]

As described above, according to the array antenna device of the present invention, it is possible to suppress the enlargement of the circuit scale and the increase in cost which occur when the DBF is performed by using all the antenna elements as channels, and the analog antenna is used. It is possible to prevent the quality deterioration of the beam output that occurs when the beam is formed in the circuit.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an array antenna device according to the present invention.

FIG. 2 is a digital beam former 14 shown in FIG.
The figure which shows 1,142.

FIG. 3 is a digital beam former 14 shown in FIG.
The figure which shows 1,142.

FIG. 4 is a configuration diagram showing another embodiment of the array antenna device according to the present invention.

FIG. 5 is a configuration diagram showing a conventional array antenna device.

[Explanation of symbols]

11~KM, 11 ¹ ~KM ^N ... antenna element, 111-1
1M ... switch circuit, 121-12M ... frequency converter,
131-13M ... A / D converter, 141, 142 ... Digital beam former, d1 ... Digital switch matrix, d11-d1M ... Delay element, d21-d2M ... Multiplier, d32-d3M ... Adder, d4 ... ROM, 101
... Transfer switch matrix, 102 ... Phase shifter,
103, 211 to 2KM ... Analog synthesizing circuit.

Claims (2)

[Claims] 1. An antenna element group having a plurality of antenna elements, and at least two antenna element outputs of the plurality of antenna elements are respectively supplied to select a predetermined antenna element output for setting an active area. A plurality of selection means, a plurality of signal conversion means for converting the outputs of the plurality of selection means directly or after frequency conversion into digital signals, and a sequence of signal outputs of the plurality of signal conversion means corresponding to the active region. An array antenna apparatus comprising: a digital beam forming unit that forms the beam by controlling the amplitude and phase of each signal after rearranging the signals in order. 2. An antenna element group having a plurality of antenna elements, and at least two antenna element outputs of the plurality of antenna elements are respectively supplied to select a predetermined antenna element output for setting an active area. A plurality of selecting means; a plurality of signal converting means for converting outputs of the plurality of selecting means directly or after frequency conversion into digital signals; and a plurality of complex weights for multiplying respective output signals from the plurality of signal converting means An array antenna apparatus comprising: a digital beam forming means for rearranging the order of signals into an order corresponding to the active area, and then multiplying each output signal to form a beam.