JPH104309A - Frequency converter for phased array antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a synthesis loss due to dispersion in a frequency of each 1st intermediate frequency signal and to make the size of the converter small. SOLUTION: A low noise block converter 4 uses a local oscillation signal to apply frequency conversion to a signal received by a plurality of antenna elements 2 into a 1st intermediate frequency signal. The phase of the intermediate frequency signals is adjusted and the intermediate frequency signals are synthesized. The converter 4 is respectively contained into a plurality of recessed parts 58 provided to one side of a chassis 20. A local oscillation circuit 6 (6a to 6e) applies a local oscillation signal to each converter 20 in common. The local oscillation circuit 6 is made up of 5 sets of 1/4-distribution amplifiers 6a to 6e and they are contained in recessed parts 32, 34 formed to the other side of the chassis 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phased array antenna for converting received signals from a plurality of antenna elements or sub-array elements into an intermediate frequency signal and then synthesizing the same, and more particularly, to frequency conversion for converting a received signal into an intermediate frequency signal. About the vessel.

[0002]

2. Description of the Related Art Conventional phased array antennas include:
Some include a plurality of antenna elements or sub-array elements and a low-noise block converter corresponding to each of them. In this phased array antenna,
Received signals from a plurality of antenna elements or sub-array elements are supplied to corresponding low-noise block converters. In these block converters, each of the received signals is frequency-converted into an intermediate frequency signal. The phases of these intermediate frequency signals are adjusted by correspondingly provided phase shifters. The phase-adjusted intermediate frequency signals are combined by a combiner. FIG. 10 shows an example of the low noise block converter.

In the low-noise block converter, a reception signal from an antenna element or a sub-array element corresponding thereto, for example, a satellite broadcast or satellite communication signal in the 11 GHz band is input to a mixer via an input probe 100, a high-frequency amplifier 102, and a band-pass filter 104. 106. The mixer 106 is also supplied with a local oscillation signal from a local oscillation circuit 108 provided for each low noise block converter. The mixer 106 converts the received signal into an intermediate frequency signal of, for example, a 1 GHz band by using the local oscillation signal. This intermediate frequency signal is supplied to the intermediate frequency amplifier 112 via the low pass filter 110. The intermediate frequency signal amplified here is supplied from an output terminal 114 to a phase shifter (not shown).

In order to operate the high-frequency amplifier 102, the intermediate-frequency amplifier 112, and the local oscillation circuit 108, a DC power supply superimposed on a coaxial cable connected to an output terminal 114 is extracted by a DC power supply separation circuit 116, After processing such as stabilization is performed by the circuit 118, the signal is supplied to the high frequency amplifier 102, the intermediate frequency amplifier 112, and the local oscillation circuit 108. These low-noise block converters are housed in the chassis one by one. FIG.
As is clear from FIG. 5, the high-frequency amplifier 102 and the intermediate-frequency amplifier 112 are each constituted by a plurality of amplification stages.

[0005]

In such a low noise block converter, the local oscillation circuit 108
It has. It is difficult to completely match the frequencies of the local oscillation signals of these local oscillation circuits 108. The frequency of each local oscillation signal varies, for example, about ± 500 KHz. Due to the variation in the frequency of each local oscillation signal, the frequency of the intermediate frequency signal from each low noise block converter also varies. Therefore, when the phases of these intermediate frequency signals are adjusted and then combined, loss occurs due to the variation in the frequency.

[0006] Each low noise block converter is individually housed in a chassis. When configuring a phased array antenna using a large number of antenna elements, a number of low noise block converters equal to the number of antenna elements is required. Therefore, these low noise block converters occupy a large volume in the phased array antenna, and the phased array antenna also becomes large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a phased array antenna in which a combined loss due to a frequency variation of each intermediate frequency signal is reduced. Another object of the present invention is to provide a phased array antenna that can be reduced in size.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, signals received by a plurality of antenna elements or sub-array elements respectively correspond to these antenna elements or sub-array elements. Using a local oscillation signal, the frequency conversion means converts the frequency into first intermediate frequency signals, adjusts the phase of these first intermediate frequency signals, and then synthesizes the signals. In common, one local oscillation means is provided.

According to the first aspect of the present invention, a local oscillation signal is commonly supplied to each frequency conversion unit from one local oscillation unit. Therefore, each frequency conversion means includes:
Since the local oscillation signal having the same frequency is supplied, the frequency of the first intermediate frequency signal output from each frequency conversion unit also matches.

According to a second aspect of the present invention, in the frequency converter for a phased array antenna according to the first aspect, each of the frequency converting means is provided in one chassis.

According to the second aspect of the present invention, since each frequency conversion means is provided in one chassis, a large installation space is not required.

According to a third aspect of the present invention, in the frequency converter for a phased array antenna according to the second aspect, each of the frequency converting means is accommodated in a plurality of recesses provided in the chassis.

According to the third aspect of the present invention, the chassis has conductivity, and the frequency converting means is provided in each of the recesses formed in the chassis. Therefore, each frequency converting means is shielded and The ground is shared.

According to a fourth aspect of the present invention, in the frequency converter for a phased array antenna according to the second aspect, the local oscillation means is provided on the chassis.

According to the fourth aspect of the present invention, since the local oscillation means is also provided in the chassis provided with each frequency conversion means, the installation space can be further reduced and the ground can be shared. .

According to a fifth aspect of the present invention, in the frequency converter for a phased array antenna according to the fourth aspect, the local oscillation means is housed in a recess provided in the chassis. The local oscillating means may be composed of a plurality of units, a concave portion may be formed corresponding to each of the units, and the unit may be accommodated in each of the concave portions.

According to the fifth aspect of the present invention, since the local oscillation means is also housed in the recess formed in the conductive chassis, it is shielded and shares the ground.

According to a sixth aspect of the present invention, in the frequency converter for a phased array antenna according to the fifth aspect, each of the frequency conversion means is accommodated in each of the recesses provided on one surface side of the chassis. The local oscillation means is housed in each of the concave portions provided on the other surface side of the chassis. In this case, each local oscillating means may be composed of a plurality of units, and these units may be accommodated in a plurality of recesses provided on the other surface side. Further, of these units, a plurality of recesses each accommodating the frequency conversion means can be formed on the opposite surface around the recess accommodating the unit that outputs the local oscillation signal to each frequency conversion means. . The unit for outputting the local oscillation signal and the plurality of frequency conversion means can be connected via a passage formed in the chassis.

According to the sixth aspect of the present invention, since each frequency conversion means is provided on one surface side of the chassis and local oscillation means is provided on the other surface side, the installation space can be further reduced. In addition, since both the frequency conversion means and the local oscillation means are housed in the recesses, they are shielded and all units share the ground.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a phased array antenna provided with a frequency converter according to the present invention includes a plurality of, for example, 16 antenna elements 2 as shown in FIG. These antenna elements 2 are for receiving satellite broadcast or satellite communication signals transmitted from a geostationary satellite such as a broadcast satellite or a communication satellite. Note that a sub-array antenna can be used instead of each antenna element 2.

The signals received by these antenna elements 2 are:
The low-noise block converters 4 corresponding to the antenna elements 2 are supplied. These low-noise block converters 4 use the local oscillation signal to frequency-convert the input received signals into first intermediate frequency signals. The local oscillation signal is supplied from one local oscillation circuit 6 to each low noise block converter 4.

The first intermediate frequency signals from the low-noise block converters 4 are supplied to phase shifters 8 provided so as to correspond to the first intermediate-frequency signals, so that the phase of the beam of each antenna element 2 becomes a specific direction. Is adjusted. Each phase-adjusted first intermediate frequency signal is supplied to the synthesizer 10 and
It is output as a synthesized first intermediate frequency signal. This synthetic first
The intermediate frequency signal is split into two by the splitter 12.
The level of one distribution output is detected by the detector 14. This detection level is supplied to the CPU 16 and the CPU 1
6 adjusts the phase of each phase shifter 8 in accordance with the detection level, and adjusts the beam of each antenna element 2 in a direction in which the reception level is maximized.

As shown in FIG. 1, each antenna element 2, low-noise block converter 4, and local oscillation circuit 6
It is provided on one chassis 20.

Each of the antenna elements 2 is arranged in a 4 × 4 matrix on one surface of an antenna substrate 22 formed, for example, in a square shape. A ground plane 24 as a ground conductor is formed on the entire area of the other surface of the substrate 22. The ground surface 22 is attached to the chassis 20 so as to contact one surface, for example, the upper surface of the chassis 20. The chassis 20 is formed of a conductive material, for example, a metal.

The local oscillation circuit 6 is provided on one surface of the chassis 20. As shown in FIG. 3, the local oscillation circuit 6 has a unit, for example, a local oscillation signal four distribution amplifier 6a. This local oscillation signal four distribution amplifier 6a
Is provided with an oscillator 18 for oscillating a local oscillation signal.
The local oscillation signal from the oscillator 18 is amplified by the amplifiers 20 and 22 and then divided into four by the four divider 24. These four distribution outputs are further divided into four by units, for example, four distribution amplifiers 6b to 6e. That is, the local oscillation signal of the oscillator 18 is divided into 16 parts. These four distribution amplifiers 6b to 6e are one of the four distribution amplifiers.
The two distribution outputs are amplified by the amplifiers 26 and 28, and further divided into four by the four distribution amplifier 30. The gains of these amplifiers 26 and 28 are four distribution amplifiers 6b to 6e.
Are the same in both cases. Therefore, the local oscillation signals supplied to each low noise block converter 4 have the same frequency and the same amplitude.

As shown in FIG. 1, a local oscillation signal four-distribution amplifier 6a is housed in a recess 32 formed in the center of one surface of the chassis 20. In addition, as is apparent from FIG. 1, the four distribution amplifier 6a is formed on a printed circuit board. Also, a concave portion 3 is provided on one surface of the chassis 20.
The concave portion 34 is also provided at the position of each vertex of the rectangle drawn around the center 2.
Are formed. In these recesses 34, four-distribution amplifiers 6 are provided.
b to 6e are arranged respectively. These four distribution amplifiers 6b to 6e are also formed on a printed circuit board.

The four division outputs from the local oscillation signal four division amplifier 6a are connected to four semi-rigid cables 36 of the same length.
Is supplied to each of the four distribution amplifiers 6b to 6e. In order to allow these semi-rigid cables 36 to pass through, the planar shape is T
Two grooves 38 are formed. Recesses 32, 34
Each of them has a square planar shape, and completely accommodates a local oscillation signal four-distribution amplifier 6a and each of the four-distribution amplifiers 6b to 6e. Since the local oscillation signal four distribution amplifier 6a and the four distribution amplifiers 6b to 6e are accommodated in the concave portions 32 and 34 provided in the conductive chassis 20, these local oscillation signal four distribution amplifiers 6a and four distribution amplifiers are provided. The leakage of the local oscillation signal from 6b to 6e is shielded. Further, the ground surface 24 of the antenna substrate 22 contacts one surface of the chassis 20 and closes the upper openings of the concave portions 32 and 34, so that the shielding effect is further enhanced.

Each low noise block converter 4 is provided on the other side of the chassis 20. The low-noise block converter 4 includes an input probe 40, like the conventional low-noise block converter shown in FIG.
High frequency amplifier 42, band pass filter 44, mixer 46, low pass filter 48, first intermediate frequency amplifier 5
0, a power supply circuit 52 and a power supply separation circuit 54.

However, each low noise block converter 4
Does not include a local oscillation circuit. A local oscillation signal is supplied to a mixer 46 from an external local oscillation circuit 6. Therefore, the local oscillation signal input unit 56 is provided in the low noise block converter 4. The intermediate frequency amplifier 50 does not have a large gain, but has such a gain as to compensate for a combined loss described later. The low noise block converter 4 is formed on a printed circuit board as shown in FIG.

These low noise block converters 4
Is housed in a recess 58 provided on the other surface of the chassis 20. These concave portions 58 are provided, for example, in a matrix of 16 corresponding to each low noise block converter 4. As shown in FIG. 5, these concave portions 58 have a rectangular planar shape, for example, a square shape. A total of four sets of these recesses 58 are formed with four sets as one set. In each set, four recesses 58 are arranged around the recess 34. One corner of each recess 54 overlaps a corner of the recess 34. However, the center of each recess 58 does not overlap with each recess 34.

The low-noise block converter 4 is inserted into these recesses 58 so as not to protrude therefrom.
Is housed. Therefore, these recesses 58 function as shield cases, and it is possible to prevent the first intermediate frequency signal generated by the mixer 46 from leaking. The other surface of the chassis 20 is covered and shielded by a shield plate 59 as shown in FIG. Therefore,
Further, leakage can be prevented.

As shown in FIG. 1, each low noise block converter 4 has an input probe 40 formed at the center thereof. These input probes 40 are provided with respective recesses 58.
Each of the input probe holes 60 penetrates from the center of the inner back portion of the chassis 20 to one side of the chassis 20, and projects upward from one surface of the chassis 20 as shown in FIG. 8. Although not shown, the protruding ends of these input probes 40 are connected to feed points of each antenna element 2. That is, each input probe hole 60 is provided with each antenna element 2.
Are provided so as to correspond to the feeding points.

Each low noise block converter 4
A local oscillation signal input section 56 is provided at one corner. These local oscillation signal input sections 56 are
b to 6e. Therefore, as shown in FIG. 6, a local oscillation signal input hole 62 is formed from a portion of each concave portion 58 overlapping the concave portion 34 toward the concave portion 34. As shown in FIG. 7, a local oscillation signal input portion 56 is inserted into these local oscillation signal input holes 62, and the distal end is accommodated in the concave portion 34.
It is connected to one of the distribution output terminals of the distribution amplifiers 6b to 6e.

The output of each low-noise block converter 4 is supplied from a power supply separation circuit 54 to, for example, a phase shifter 8 via a coaxial cable 64. At this time, the coaxial cable 64
Is a coaxial cable passage hole 66 formed in the shield plate 59.
And is supplied to the phase shifter 8. That is, in the frequency conversion device, as shown in FIG. 8, an input probe 40 connected to the feeding point of the antenna element 2 protrudes from one surface of the chassis 20, and a coaxial cable 64 connected to the phase shifter 8 from the other surface. And each low noise block converter 4
The local oscillation circuit 6 is housed in the chassis 20.

In the frequency converter configured as described above, each low-noise block converter 4 and local oscillation circuit 6 are provided in one chassis 20, so that the phased array antenna can be installed in a small installation space. . Each low noise block converter 4 is supplied with a local oscillation signal having the same frequency and the same amplitude from the local oscillation circuit 6, so that the first intermediate frequency signal generated by each low noise block converter 4 has the same frequency,
It has the same amplitude. Therefore, even when the signals are combined by the combiner 10, no large loss occurs. The chassis 20 provided with the low noise block converter 4 and the local oscillation circuit 6 is covered with a radome (not shown). And since many low noise block converters 4 are used,
A large amount of heat is generated, the temperature inside the radome rises greatly, and thermal stress occurs in the block converter 4 and the like, which may cause performance degradation. Therefore, in each low noise block converter 4, the first intermediate frequency amplifier 50 has a gain enough to compensate for the combined loss in the phase shifter 8, thereby suppressing heat generation and saving power.

The above embodiment is merely an example of the present invention, and various modifications are possible. For example, the local oscillation circuit 6
Distributes the local oscillation signal into four, and further divides the four divided outputs by four.
Has been distributed. For example, after the oscillation signal from the oscillator 18 is amplified by the amplifier 70 as shown in FIG.
The local oscillator signal may be distributed n by the n distributor 72 so as to supply the local oscillator signal to the low-noise block converters 401 to 40n of (an arbitrary integer of 2 or more) units. In the above embodiment, each low noise block converter 4 has its input section connected to the input probe 40.
However, instead of this, for example, a waveguide can be used.

[0037]

As described above, according to the first aspect of the present invention, each frequency conversion means is supplied with a local oscillation signal from one local oscillation means. , A local oscillation signal of the same frequency is supplied. Therefore, the frequency of the first intermediate frequency signal output from each frequency conversion unit also matches. As a result, even if the first intermediate frequency signals are combined, no combined loss occurs.

According to the second aspect of the present invention, since each frequency conversion means is provided in one chassis, a large installation space is not required.

According to the third aspect of the present invention, the chassis has conductivity, and the frequency converting means is provided in each of the recesses formed in the chassis. The leakage of the intermediate frequency signal can be prevented, and the ground can be shared.

According to the fourth aspect of the present invention, since the local oscillating means is also provided on the chassis provided with each frequency converting means, the installation space can be further reduced.

According to the fifth aspect of the invention, the local oscillation means is also housed in the recess formed in the conductive chassis, so that not only the frequency conversion means but also the local oscillation means are shielded. Therefore, not only the first intermediate frequency signal but also the local oscillation signal can be prevented from leaking, and the ground can be shared.

According to the sixth aspect of the present invention, since each frequency conversion means is provided on one side of the chassis and the local oscillation means is provided on the other side, the installation space can be further reduced. Can be. Further, since the frequency conversion means and the local oscillation means are provided on the opposite surfaces of one chassis, the signals of each other do not interfere with each other. Further, since each of the frequency conversion means and the local oscillation means is provided in each of the concave portions provided corresponding to them, it is possible to reliably prevent the first intermediate frequency signal and the local oscillation signal from leaking, and The ground can be shared.

[Brief description of the drawings]

FIG. 1 is a partially assembled view of an embodiment of a phased array antenna using a frequency conversion device according to the present invention.

FIG. 2 is a block diagram of the embodiment.

FIG. 3 is a block diagram of a local oscillation circuit used in the embodiment.

FIG. 4 is a block diagram of a low noise block converter used in the embodiment.

FIG. 5 is a bottom view of the chassis of the embodiment.

FIG. 6 is a sectional view taken along line AA of FIG.

FIG. 7 is a sectional view taken along the line BB of FIG. 5;

FIG. 8 is a front view of this embodiment.

FIG. 9 is a block diagram of a modification of the local oscillation circuit used in this embodiment.

FIG. 10 is a block diagram of a low-noise block converter used for a conventional phased array antenna or parabolic antenna.

[Explanation of symbols]

 2 antenna element 4 low noise block converter 6 local oscillation circuit 8 phase shifter 10 synthesizer 20 chassis 32 34 58 recess

Claims (6)

[Claims] 1. A signal received by each of a plurality of antenna elements or sub-array elements is converted into a first signal by a frequency converter corresponding to each of the antenna elements or sub-array elements, using a local oscillation signal.
In a phased array antenna for performing frequency conversion to an intermediate frequency signal, adjusting the phases of these first intermediate frequency signals, and synthesizing the same, one local oscillation means is provided commonly to the frequency conversion means. Frequency converter for phased array antennas. 2. The frequency converter for a phased array antenna according to claim 1, wherein each of said frequency conversion means comprises:
A frequency converter for a phased array antenna, wherein the frequency converter is provided in one chassis. 3. The frequency converter for a phased array antenna according to claim 2, wherein each of the frequency conversion means includes:
A frequency converter for a phased array antenna, wherein the frequency converter is housed in a plurality of recesses respectively provided in the chassis. 4. The frequency converter for a phased array antenna according to claim 2, wherein said local oscillation means is provided on said chassis. 5. The frequency converter for a phased array antenna according to claim 4, wherein said local oscillation means is housed in a recess provided in said chassis. 6. The frequency converter for a phased array antenna according to claim 5, wherein each of the frequency conversion means includes:
A phased array antenna which is housed in each of the recesses provided on one surface side of the chassis, and wherein the local oscillation means is housed in each of the recesses provided on the other surface side of the chassis. Frequency converter.