JPH11308045A - Antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a conformal array antenna device which simultaneously synthesizes plural multiple beams, and also, effectively uses all of the elements at all times and prevents crossed polarization and electromagnetic interference due to polarization differences of each element antenna. SOLUTION: Plural pieces of conformal array antenna elements which are arranged along a structural base consist of element antennas 61 to 6n , of transmitting and receiving switching devices 111 to 11n , of transmitting systems 121 to 12n and of receiving systems 151 to 15n . The receiving system in each element is provided with a digital beam formation circuit 10 to synthesize a received signal that is converted into a digital signal, including a phase and amplitude and to form a beam.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conformal array antenna used for a radar system.

[0002]

2. Description of the Related Art FIG. 5 is a block diagram showing a conventional antenna device. In the drawing, reference numeral 1 denotes a conformal array antenna having a plurality of elements provided on a hemisphere, and reference numeral 2 denotes the conformal array antenna 1. Hemispherical structural substrate, 3
₁ to 3 _n is the n arranged along the structural base element, 4 ₁ to 4 _n is n signal lines connected to the element 3 ₁ to 3 _n, 5 is the signal line 4 ₁ 4 _n is a microwave beam forming circuit connected to the circuit. Figure 6 shows the 3 ₁ Examples is a block diagram of a device 3 ₁ to 3 _n which constitutes the conformal array antenna 1, 6 ₁ is an element antenna.

Next, the operation will be described. Microwave power is received by the element antenna 6 ₁ to 6 _n of elements 3 ₁ to 3 _n which are arranged along the structural substrate 2 hemispherical conformal array antenna 1, via the signal line 4 ₁ to 4 _n The microwave signal is transmitted to the microwave beam forming circuit 5, and is combined with the microwave signal using a microwave phase shifter, a microwave variable attenuator, a microwave switch, a microwave coupler, or the like, and a beam is formed.

[0004]

Since the conventional antenna device is constructed as described above, the beam of the antenna can be arbitrarily formed over a half space. However, a phase shifter, an attenuator, a switch coupler, a distributor, etc. When many beams are formed using the microwave components described above, the shape loss increases, and only a limited number of beams can be combined at the same time. Further, when used as part of the radar apparatus is assumed that for a beam in a certain desired direction in half-space, of the conformal array elements 3 ₁ to 3 _n of the antenna 1, as viewed from its desired direction The elements in the shaded area cannot be used effectively. In particular, the beam scanning angle from the zenith direction of the hemisphere becomes 90 °.
As ゜ approaches, nearly half of the elements are not used effectively.

When linearly polarized antennas are used as the element antennas 6 _{1 to} 6 _n of the conformal array antenna 1, the element antennas 6 _{1 to} 6 on the conformal array antenna 1 when viewed from an arbitrary direction are used. _Since the polarization planes between _n are different from each other, cross polarization components are generated.

Further, since a large number of signal lines are used, there is a problem that electromagnetic interference occurs between the signal lines and the size becomes large.

[0007] The present invention is possible combining a plurality of multi-beams at the same time been made to solve the above problem, the whole element always effectively used it is possible to each of the antenna elements 6 ₁ An object of the present invention is to provide an antenna device that can solve the problems of cross polarization and electromagnetic interference due to 6 _n polarization differences.

[0008]

An antenna device according to a first aspect of the present invention comprises an element antenna, a transmission / reception switch connected to the element antenna for switching between transmission and reception, a transmission system, and a reception system. A phase controller for controlling the phase of the microwave signal, and a microwave signal connected to the transmission / reception switch and phase-controlled by the phase controller, and transmitted to the element antenna via the transmission / reception switch. Having a first amplifier, the receiving system is connected to the duplexer, the second amplifier to amplify the microwave signal received by the element antenna through the duplexer,
An element having an analog-to-digital converter that converts a microwave signal amplified by the second amplifier into a digital signal; a structural base having a given shape such as an aircraft surface or a ship surface; and A plurality of conformal array antennas arranged along the structural base, a microwave power distributor for distributing microwave signals, and each of the microwave signals distributed by the microwave power distributor, A plurality of transmission system signal lines respectively transmitting to the phase controller in the transmission system of the element, and a plurality of reception system signal lines respectively transmitting a digital signal supplied from the analog-to-digital converter in the reception system of each of the above elements And a digital beam forming circuit for forming a beam by synthesizing the digital signals transmitted on the respective receiving system signal lines. It is those equipped.

The antenna device according to the second aspect of the present invention includes:
An element antenna, a transmission / reception switch connected to the element antenna for switching transmission and reception, a transmission system, and a reception system, wherein the transmission system is a first optical demodulator for demodulating a transmitted optical signal into a microwave signal; A phase controller for controlling the phase of the microwave signal demodulated by the first optical demodulator, and amplifying the microwave signal that is phase-controlled by the phase controller and connected to the transmission / reception switch; And a high-power amplifier for transmitting to the element antenna through the antenna.The reception system is connected to the transmission / reception switch and amplifies a microwave signal received by the element antenna via the transmission / reception switch. A noise amplifier, an analog-to-digital converter for converting a microwave signal amplified by the low-noise amplifier into a digital signal, and a digital signal converted by the analog-to-digital converter. An element having a first optical modulator for modulating a signal into an optical signal, an array antenna configured by arranging a plurality of the elements, a microwave power divider for distributing a microwave signal, and the microwave power A plurality of second optical modulators for modulating each of the microwave signals distributed by the distributor into an optical signal, and a transmission system for transmitting the optical signals modulated by the respective second optical modulators to the respective elements; A plurality of first optical fibers respectively transmitting to the first optical demodulator, and a plurality of second optical fibers respectively transmitting the optical signal supplied from the first optical modulator in the receiving system of each of the above elements. An optical fiber, a plurality of second optical demodulators for demodulating optical signals transmitted through the respective second optical fibers into digital signals, and a digital signal demodulated by the respective second optical demodulators. Synthesize It is obtained by including a digital beam forming circuit for forming a beam.

Further, an antenna device according to a third aspect of the present invention comprises an element antenna, a transmission / reception switch connected to the element antenna for switching between transmission and reception, a transmission system, and a reception system. A first optical demodulator that demodulates the signal into a microwave signal, a phase controller that controls the phase of the microwave signal demodulated by the first optical demodulator, and the phase controller that is connected to the transmission / reception switch. A high-power amplifier that amplifies the phase-controlled microwave signal and transmits the signal to the element antenna via the transmission / reception switch, and the reception system is connected to the transmission / reception switch via the transmission / reception switch. A low-noise amplifier that amplifies the microwave signal received by the element antenna, an element having a first optical modulator that modulates the microwave signal amplified by the low-noise amplifier into an optical signal, A structural base having a given shape such as a surface of an airplane or a ship, a conformal array antenna having a plurality of the above elements arranged along the structural base, and a microwave for distributing microwave signals. A power divider, a plurality of second optical modulators each modulating the microwave signal distributed by the microwave power distributor into an optical signal, and light modulated by each of the second optical modulators. A plurality of first optical fibers for transmitting the signal to the first optical demodulator in the transmission system of each of the elements,
A plurality of second optical fibers respectively transmitting the optical signals supplied from the first optical modulator in the receiving system of each of the above elements, and the optical signals transmitted through the respective second optical fibers are respectively subjected to microwaves. A plurality of second optical modulators for demodulating into a signal or an IF signal, and a plurality of analog-to-digital converters for converting a microwave signal or an IF signal demodulated by each of the second optical demodulators into a digital signal And a digital beam forming circuit for forming a beam by synthesizing the digital signals converted by the respective analog-to-digital converters.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. In Figure 1, 1 is a conformal array antenna having a plurality of elements on the hemisphere, 2 structural substrate hemispheres constituting the conformal array antenna 1, 3 ₁ to 3 _n to the structural substrate 2 N elements arranged along the line, 7 _{1 to} 7 _n are transmission system signal lines connected to the transmission system of the elements 3 _{1 to} 3 _n , and 8 is micro connected to the transmission system signal lines 7 _{1 to} 7 _n. Wave power distributors, 9 _{1 to} 9 _n, are reception signal lines connected to the reception systems of the elements 3 _{1 to} 3 _n , and 10 are the reception signal lines 9 _{1 to} 9 _n
Is a digital beam forming circuit connected to. FIG. 2 is a configuration diagram showing a signal flow in the antenna device,
3 _{1 to} 3 _n are elements, 6 _{1 to} 6 _n are element antennas, 11 ₁
11 to 11 _n are transmission / reception switches, 12 _{1 to} 12 _n are transmission systems connected to the transmission / reception switches 11 _{1 to} 11 _n , 13 _{1 to} 13 _n are high-output amplifiers constituting the transmission systems 12 _{1 to} 12 _n , 1
4 ₁ to 14 _n are phase controller constituting the transmission system, 7 ₁
Transmission system signal line connected to the transmission system 12 ₁ to 12 _n are,
8 is a microwave power distributor connected to the transmission system signal line, 15 ₁ to 15 _n are reception systems connected to the transmission / reception switchers 11 _{1 to} 11 _n , and 16 _{1 to} 16 _n are reception systems 15 ₁ to 15 _n
Low noise amplifier constituting 15 _n, 17 ₁ ~17 _n is analog-digital converter constituting the reception system _{15 1 ~15 n, 9 1 ~9} n the reception system to be connected to the reception system 15 ₁ to 15 _n The signal line 10 is a digital beam forming circuit connected to the signal line of the receiving system.

Next, the operation will be described. The microwave signal input to the microwave power divider 8 has a desired amplitude,
The signal is distributed to the output of the n terminal having the phase and is transmitted to the transmission system signal line 7 _1-
Through the 7 _n elements 3 ₁ to 3 _n of the transmission system 12 ₁ to 12 _n
Transmitted to In the microwave signal is a high power amplifier 13 ₁ to 13 _n receives the phase change as to form a desired antenna beam in the phase controller 14 ₁ to 14 _n of the transmission system 12 ₁ to 12 _n of the element 3 ₁ to 3 _n after being amplified, it is radiated into space from the duplexer 11 ₁ to 11 element mounted on structural base 2 of the conformal array antenna 1 through the _n antenna 6 ₁ to 6 _n. Is radiated into space microwave signal reflected again element antennas 6 ₁ at the target
6 _n are received by and transmitted to the receiving system 15 ₁ to 15 _n of the duplexer 11 device via the _{1 ~11 n} 3 _{1 ~3 n.}
Microwave signal input to the receiving system 15 ₁ to 15 _n are amplified by the low noise amplifier 16 ₁ ~ 16 _n. Low noise amplifier 1
6 _1-16 amplified microwave signal at _n are converted directly or IF output is analog-to-digital converter 1
The signals are converted into digital signals containing information on the phase and amplitude by means of 7 _{1 to} 17 _n . The digital signal is received by the receiving system signal line 9 ₁
.About.9 _n are transmitted and digitally formed by the digital beam forming circuit 10 not as a microwave signal but as a digital signal using techniques such as an individual Fourier transform, a fast Fourier transform, and a Wingrad Fourier transform. Therefore, it is possible to digitally process a plurality of signals from the elements 3 _{1 to} 3 _{n in} parallel according to an arbitrary beam shape. Also, all the elements arranged on the hemispherical surface 3 ₁ to 3 _n
Information from all directions of the half space can always be obtained. Therefore, by directing a plurality of reception beams in an arbitrary direction in a half space irrespective of the direction of the antenna beam of the transmission wave, all the elements can be always effectively used.

Even when linearly polarized elements are used as the element antennas 6 _{1 to} 6 _n , the polarization of the transmission signal and the polarization of the reception signal reflected from the target can be considered for each of the element antennas 6 _{1 to} 6 _n. Since the signals from the target are converted into digital signals containing phase and amplitude information at the stage of the elements 3 _{1 to} 3 _{n and} are synthesized by the digital beam forming circuit 10, the polarization difference between the elements is different. The problem of cross-polarization due to is solved.

In the above-described embodiment, the structural base 2 having a hemispherical shape is used as the conformal array antenna 1. However, the present invention is not limited to this. The ship, aircraft missile, land vehicle, satellite, and ground radar It may be a shape having a part of a structure such as a site, a part of a cylinder, a sphere, a cone, or the like, or a part or a plurality of curved surfaces of a composite shape of these. The polarization is not limited to linear polarization, and circular polarization can also be used.

Further, in the above embodiment, the elements 3 ₁ to 3 ₁
3 optical signals for transmission of _n and a microwave signal of a power distribution circuit 8, and the digital beam forming circuit 10 can be expected the same operation also when used.

FIG. 3 shows an embodiment of the case where optical signals are used for signal transmission between the elements 3 _{1 to} 3 _n and the microwave power distribution circuit 8 and the digital beam forming circuit 10. The optical modulator 18 is connected to the output end of the optical modulator 8.
_n + 1 ~ 18 _2n adding converts the microwave signal to an optical signal fiber 19 _n + 1 ~19 _2n by the element 3 ₁ to 3 _n optical demodulator 20 _n that are added to the transmission system 12 ₁ to 12 _n of ₊₁ to
Transmitting a signal to 20 _2n are converted here into a microwave signal from the optical signal. Element 3 in the case of receiving ₁ to 3 _n optical modulator 18 ₁ ~ 18 _n in the receive system 15 ₁ to 15 _n of
Converts a digital signal from an electrical signal to an optical signal,
The optical fibers 19 _{1 to} 19 _n are converted into digital electric signals again by the optical demodulators 20 _{1 to} 20 _n added before the digital beam forming circuit 10. This figure 3
According to the method, the signal transmission between the devices is performed using the optical signal, so that the problem of the electromagnetic interference between the signal lines is solved, and the signal line system can be downsized because the optical fiber is used.

The reason why the microwave signal (received signal) of the receiving system is optically transmitted after A / D conversion will be described below. Radar needs to handle a wide range of signal levels, from small targets as far away as hundreds of kilometers to large mountains at short distances.
The dynamic range is usually about 100 dB.
These signals exist above and below the noise level. A signal can be extracted by coherent integration or the like even for a signal having a noise level or less, and in this case, white noise is assumed. Also in the present invention, each channel must satisfy this condition, and a signal transmission system having a wide dynamic range is required. However, in general, the dynamic range of an optical system has an upper limit due to a limitation on the output of a normal laser (about 10 dBm) and a lower limit due to noise inherent to the laser (shot noise or quantum noise).
It is about dBc / Hz, and if the band of the radar is several MHz (for example, 5 MHz), it becomes 50 to 60 dB (58 dB). Therefore, in order to compensate for these drawbacks and take advantage of optical transmission, it is necessary to perform A / D conversion of a signal once, convert the signal to a digital signal, and then perform transmission. As a result, it is possible to transmit the signal while including the noise component of the input signal and a signal smaller than the noise component while the dynamic range is widened.

[0018] Figure 4 is an analog-to-digital converter in shows another embodiment using an optical signal for transmission of signals 17 ₁ -
The position of the 17 _n can be expected the same operations as example a and the embodiment example in the case of during the optical demodulator 20 ₁ to 20 _n and the digital beam forming circuit 10. In the figure, the microwave signal is directly or IF-converted in the optical modulators 18 ₁ to 18 _n
It is converted to the converted by the optical signal to the optical fiber 19 ₁ to 1
Via 9 _n it is transmitted to the optical demodulator 20 ₁ to 20 _n.
The optical signal is converted into a digital signal after being converted directly or IF in the optical demodulator 20 ₁ to 20 _n are demodulated by an analog-digital converter 17 ₁ to 17 _n.

[0019]

As described above, according to the first aspect of the present invention, the receiving system in each element of the conformal array antenna converts a microwave signal into a digital signal, and after transmitting the digital signal, transmits the digital beam forming circuit. 10 can be arbitrarily combined, so that it is possible to simultaneously form multiple types and multiple beams, which cannot be realized by the conventional conformal array antenna, and to always effectively use all elements, and to have transmission and reception systems in the same element respectively. Therefore, the problem of cross polarization can be solved.

According to the second and third aspects of the present invention, since the optical fiber is used as the signal transmission line, it is possible to significantly reduce electromagnetic interference and downsize the signal transmission line.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an antenna device according to a first embodiment of the present invention.

FIG. 2 is a connection diagram between devices of the antenna device according to the present invention.

FIG. 3 is a connection diagram between devices according to the first embodiment of the present invention when an optical signal is used in a signal transmission system.

FIG. 4 is a connection diagram between devices showing another embodiment of the present invention when an optical signal is used for a signal transmission system.

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

FIG. 6 is a configuration diagram of elements of a conventional antenna device.

[Explanation of symbols]

1 conformal array antenna, 2 structural base,
3 element, 4 signal line, 5 microwave beam forming circuit, 6 element antenna, 7 transmitting system signal line, 8 microwave power divider, 9 receiving system signal line, 10 digital beam forming circuit, 11 transmission / reception switch, 12 transmission System, 13
High power amplifier, 14 phase controller, 15 reception system, 16
Low noise amplifier, 17 analog-to-digital converter, 18
Optical modulator, 19 optical fiber, 20 optical demodulator.

 ──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Takashi Katagi 325 Kamimachiya, Kamakura City Mitsubishi Electric Corporation Kamakura Works

Claims (3)

[Claims] An element antenna, a transmission / reception switch connected to the element antenna for switching transmission and reception, a transmission system, and a reception system, wherein the transmission system controls a phase of a transmitted microwave signal, And a first amplifier that is connected to the transmission / reception switch and amplifies the microwave signal that is phase-controlled by the phase controller and transmits the signal to the element antenna via the transmission / reception switch. A second amplifier connected to the duplexer for amplifying the microwave signal received by the element antenna via the duplexer, converting the microwave signal amplified by the second amplifier into a digital signal An analog-to-digital converter, a structural base having a given shape such as an aircraft surface or a ship surface, and a plurality of the elements arranged along the structural base. A conformal array antenna configured as described above, a microwave power splitter for splitting microwave signals, and each microwave signal split by the microwave power splitter to a phase controller in a transmission system of each of the elements. A plurality of transmission system signal lines for transmitting each; a plurality of reception system signal lines for transmitting digital signals supplied from an analog-to-digital converter in a reception system of each of the elements; and each of the reception system signal lines And a digital beam forming circuit for forming a beam by synthesizing a digital signal transmitted through the antenna device. 2. An element antenna, a transmission / reception switch connected to the element antenna for switching between transmission and reception, a transmission system, and a reception system, wherein the transmission system demodulates a transmitted optical signal into a microwave signal. An optical demodulator, a phase controller for controlling the phase of the microwave signal demodulated by the first optical demodulator, and amplifying the microwave signal that is connected to the transmission / reception switch and phase-controlled by the phase controller. A high-output amplifier for transmitting to the element antenna via the duplexer, wherein the receiving system is connected to the duplexer and received by the element antenna via the duplexer. A low-noise amplifier that amplifies a signal, an analog-to-digital converter that converts a microwave signal amplified by the low-noise amplifier into a digital signal, and a signal that is converted by the analog-to-digital converter. A first optical modulator that modulates the digital signal into an optical signal, an array antenna configured by arranging a plurality of the above elements, a microwave power divider that distributes microwave signals, A plurality of second optical modulators that respectively modulate the microwave signals distributed by the wave power distributor into optical signals, and the optical signals that are modulated by the respective second optical modulators to the respective elements. A plurality of first optical fibers respectively transmitting to the first optical demodulator in the transmission system, and a plurality of first optical fibers respectively transmitting the optical signal supplied from the first optical modulator in the reception system of each of the elements. Two optical fibers, a plurality of second optical demodulators for demodulating optical signals transmitted through the respective second optical fibers into digital signals, and a digital demodulator demodulated by the respective second optical demodulators. Antenna apparatus characterized by No. was synthesized and and a digital beam forming circuit for forming a beam. 3. An element antenna, a transmission / reception switch connected to the element antenna for switching between transmission and reception, a transmission system, and a reception system, wherein the transmission system demodulates the transmitted optical signal into a microwave signal. An optical demodulator, a phase controller for controlling the phase of the microwave signal demodulated by the first optical demodulator, and amplifying the microwave signal that is connected to the transmission / reception switch and phase-controlled by the phase controller. A high-output amplifier for transmitting to the element antenna via the duplexer, wherein the receiving system is connected to the duplexer and received by the element antenna via the duplexer. A device having a low-noise amplifier for amplifying a signal, a first optical modulator for modulating a microwave signal amplified by the low-noise amplifier into an optical signal, and a given shape such as an aircraft surface or a ship surface A structural base, a conformal array antenna configured by arranging a plurality of the elements along the structural base, a microwave power splitter for splitting microwave signals, and the microwave power splitter. A plurality of second optical modulators each modulating the distributed microwave signal into an optical signal, and an optical signal modulated by each of the second modulators in a first transmission system of the respective elements. A plurality of first optical fibers respectively transmitting to the optical demodulator, and a plurality of second optical fibers respectively transmitting the optical signal supplied from the first optical modulator in the receiving system of each element, The optical signal transmitted through each second optical fiber is converted into a microwave signal or IF
A plurality of second optical modulators for demodulating the signals into microwave signals or I / O signals demodulated by the respective second optical demodulators;
A plurality of analog-to-digital converters for converting the F signal into digital signals; and a digital beam forming circuit for forming a beam by combining the digital signals converted by the respective analog-to-digital converters. Antenna device.