JP3076784B2 - Antenna device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conformal array antenna used for a radar system. 2. Description of the Related Art FIG. 5 is a block diagram showing a conventional antenna device. In FIG. 5, reference numeral 1 denotes a conformal array antenna having a plurality of elements on a hemisphere, and reference numeral 2 denotes a conformal array antenna. Hemispherical structural substrate constituting 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 configured as described above, the beam of the antenna can be arbitrarily formed over a half space, but the phase shifter, the attenuator, the switch coupler, When many beams are formed by using a microwave component such as a distributor, 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, and 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. An antenna device according to a first 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 unit , and a reception unit.
A plurality of elements, wherein the transmission unit controls the phase of the transmitted microwave signal, and amplifies the microwave signal that is connected to the transmission / reception switch and the phase of which is controlled by the phase controller. Having a first amplifier for transmitting to the element antenna via the duplexer , and
A second amplifier is connected to the duplexer and amplifies the microwave signal received by the element antenna through the duplexer, and the phase of the microwave signal amplified by the second amplifier is amplified. A plurality of elements having an analog-to-digital converter for converting into a digital signal containing amplitude information, and at least a surface of an aircraft or a surface of a ship,
A structural substrate having a shape given part has a curved surface, the element of the each plurality arranged along the structural base
Consisting of a conformal array antenna unit , a microwave power splitter for splitting microwave signals, and a plurality of microwave power splitters for transmitting each microwave signal split by the microwave power splitter to a phase controller of each of the elements. And a plurality of receiving signal lines respectively transmitting digital signals supplied from the analog-to-digital converters of the respective elements, and the conformal array antenna.
And a digital beam forming circuit for forming a beam by synthesizing a digital signal transmitted through each of the receiving-system signal lines and separated from the unit . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment 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
To 9 _n individual Fourier transform the digital beam forming circuit 10 are transmitted to a fast Fourier transform, is beam combining as a digital signal rather than as a microwave signal using techniques such as Winograd 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-mentioned 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, ground radar, etc. 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. Microwave signal in FIG directly or IF in the optical modulator 18 ₁ ~ 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 is evident from the foregoing description, according to the present invention, optionally in the digital beam forming circuit after converting the receiving system at each element of the conformal array antenna unit microwave signal into a digital signal, and transmission Can be combined with conventional conformal array antennas and planar array antennas.
More multibeam simultaneously formed which could not be achieved in containers, it is possible to always efficient use of all the elements, in particular, Ann transmission wave
In any direction on the curved surface regardless of the direction of the tena beam
By directing multiple receive beams, a wide angular area
Thus, simultaneous formation of a plurality of types of beams becomes possible. In addition, since the transmitting unit and the receiving unit are respectively provided in the same element, the problem of cross polarization can be solved. Further, a digital beam forming circuit arranged apart from the conformal array antenna unit and connected by a reception system signal line,
A microwave power divider connected by a transmission system signal line, and transmitting a signal received by the conformal array antenna unit and converted into a digital signal including phase and amplitude information through a reception signal line, thereby forming a conformal signal. In addition to enabling digital beam formation in the array antenna unit, it is possible to reduce electromagnetic interference between signal lines and increase the number of reception signal lines, thereby realizing a smaller reception signal line. [0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing 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. [Description of Signs] 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 Continuation of the front page (72) Inventor Koji Katagi 325 Kamimachiya, Kamakura-shi Kamakura Works, Mitsubishi Electric Corporation (56) References JP-A-59-193603 (JP, A) JP-A-55- 8197 (JP, A) JP-A-58-147667 (JP, A) 1982 INTERNATIONAL SYMPOSIUM DIGEST A TENNAS AND AND PROPAGATION, VOLUME 2, P431-434, AN EXPERIMENTAL LARGE RANDOM INTERFUNCTION INTERFRONT APPLICATION S IEEE PROCEEDINGS VOL. 127, Pt. F. No. 4, AU GUST 1980, PP257-265, Digital Beam forming for sonar systems (58) Fields investigated (Int. Cl. ⁷ , DB name) H01Q 21/20 G01S 7/02 G01S 7/03 H01Q 3/30 H01Q 23/00

Claims (1)

(57) [Claims] An element antenna, a transmission / reception switch connected to the element antenna for switching transmission and reception, a transmission unit , and a reception unit
A plurality of elements, the transmitting unit controls the phase of the transmitted microwave signal, and a phase controller that is connected to the transmission / reception switch and amplifies the microwave signal whose phase is controlled by the phase controller; A first amplifier for transmitting to the element antenna via a transmission / reception switch , and wherein the reception system is connected to the transmission / reception switch and received by the element antenna via the transmission / reception switch; A plurality of elements having an analog-to-digital converter for converting a microwave signal amplified by the second amplifier into a digital signal containing phase and amplitude information, , At least partially on the surface of an aircraft or the surface of a ship
Distributing the structural base of given shape has a surface, and conformal array antenna unit with <br/> element of the each formed by a plurality arranged along the structural base, a microwave signal A microwave power divider; a plurality of transmission system signal lines for transmitting each microwave signal distributed by the microwave power divider to a phase controller of each of the elements; and an analog / digital signal of each of the elements. A plurality of receiving system signal lines for transmitting digital signals supplied from the converter, respectively, and separated from the conformal array antenna unit
Is an antenna apparatus characterized by synthesizing the digital signals transmitted by the receiving system signal lines of the respective, and and a digital beam forming circuit for forming a beam.