JP2004363801A - Array antenna feeder, array antenna system using same, and variable beam pattern broadcasting satellite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of decreasing the number of power amplifiers for feeding electric power to an array antenna. <P>SOLUTION: A phased array antenna feeder that feeds electric power to a plurality of array antennas constituting a phased array antenna to be mounted on a satellite is equipped with power amplifying means that feed electric power to groups of the plurality of antenna elements and the number of which is less than that of the antenna elements and a variable power distributor that distributes the output of the power amplifying means to the respective antenna elements in the groups so that the distribution ratio of the electric power can be varied. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a feeder circuit of a phased array antenna mounted on a variable beam pattern broadcasting satellite, and relates to a technique for reducing power amplifiers by combining antenna elements in consideration of an amplitude value excited in each antenna element. is there.
[0002]
[Prior art]
There is known a technology in which a phased array antenna is mounted on a broadcasting satellite and an intensified beam is formed in an area where radio wave attenuation occurs due to rainfall (for example, see Non-Patent Document 1).
[0003]
As a configuration example of such a phased array antenna for satellite installation, a configuration as shown in FIG. 1 can be considered.
[0004]
The received signal received by the receiving antenna 1 is band-limited by a BPF (band pass filter) 2 corresponding to the channel, amplified by an LNA (low noise amplifier) 3, converted to a transmission frequency by a frequency converter 4, and , And then input to the distributor 13. At this time, an amplifier 5 as a driver amplifier is inserted to compensate for equipment loss and distribution loss in the distributor 13.
[0005]
The signal distributed to the number of antenna elements by the distributor 13 is subjected to control calculated by the excitation amplitude / phase control unit 14 in order to form an intensified beam in an area where radio wave attenuation has occurred due to rainfall.
[0006]
The excitation amplitude and the excitation phase are controlled by an attenuator (referred to as ATT in the drawing) 7 and the like of the input section of the power amplifier 8 shown in FIG. Each of the controlled signals is supplied to the array antenna element 11 and becomes a transmission signal forming a desired antenna pattern.
[0007]
[Non-patent document 1]
Shoji Tanaka, Tetsuya Yamada, Takao Murata: "Study on radiation pattern of phased array-fed reflector antenna for on-board broadcasting satellite", IEICE Technical Report, AP2001-169, PP. 61-67 (2002-1)
[0008]
[Problems to be solved by the invention]
In order to form an intensified beam in an area where radio wave attenuation has occurred due to rainfall when providing broadcasting services using the above-mentioned satellite phased array antenna, a reflector type combining a reflector with multiple feeding array antennas A phased array antenna must be mounted on the satellite. In this phased array antenna, as shown in FIG. 2, for example, in the Ka band, by combining a reflecting mirror 15 having a diameter of about 10 meters with 100 to 300 feeding array antennas 16, a specified value of transmission power is provided in the clear sky region. While radiating, the rainfall area having a diameter of about 100 km in the service area can be increased by the specified value +10 dB.
[0009]
In the conventional phased array antenna for onboard satellite, one power amplifier 8 is connected to each antenna element 11. For the power amplifier 8, it is difficult to apply a semiconductor element such as an MMIC (microwave integrated circuit) at a frequency higher than the Ka band from the viewpoint of output efficiency, and it is usually necessary to use a TWTA (travelling wave tube amplifier) or the like. And TWTA have the disadvantage that both volume and weight are large.
[0010]
Thereby, the power supply circuit to the antenna element 11 becomes large-scale. At the same time, implementation on satellites becomes difficult. Also, when the number of power amplifiers 8 increases, the problem due to heat generation cannot be ignored. Furthermore, the cost of the system is enormous.
[0011]
The present invention has been made in view of these problems, and an object of the present invention is to provide a technique capable of reducing the number of power amplifiers.
[0012]
The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
[0013]
[Means for Solving the Problems]
The following is a brief description of an outline of typical inventions disclosed in the present application.
[0014]
(1) A phased array antenna power supply device for supplying power to a plurality of antenna elements constituting a phased array antenna for use in a satellite, wherein the antenna element supplies power to each group in which the plurality of antenna elements are grouped. And a variable power distributor for distributing the output of the power amplifying means to each antenna element in the group so that the distribution ratio can be changed.
[0015]
(2) In the phased array antenna power supply device according to (1), the variable power distributor has a group whose distribution ratio is changed at 3 dB or more.
[0016]
(3) A phased array antenna system mounted on a satellite, comprising: a plurality of antenna elements; and a power amplifying means having a number less than the number of the antenna elements for supplying power to each group in which the plurality of antenna elements are grouped; A variable power distributor for distributing the output of the power amplifying means to each antenna element in the group such that the distribution ratio can be changed.
[0017]
(4) A variable beam pattern broadcasting satellite capable of forming an intensified beam, wherein a plurality of antenna elements constituting a phased array antenna and power are supplied to each group in which the plurality of antenna elements are grouped. Power amplifying means less than the number of antenna elements, a distributor for distributing a received signal received by a receiving antenna to the power amplifying means, and changing an output of the power amplifying means to distribute power to each antenna element in the group. And a variable power distributor for distributing as much as possible.
[0018]
According to the above-described means, the power amplifying means having less than the number of antenna elements feeds power to each group in which the plurality of antenna elements are grouped, and the variable power divider outputs the output of the power amplifying means to each antenna in the group. The configuration is such that the power distribution ratio is distributed to the elements in a changeable manner, and the number of power amplifying means can be reduced. Therefore, the size of the power supply circuit can be reduced, and the cost can be reduced.
[0019]
Further, since the number of power amplifying means can be reduced, the amount of heat generated by the power supply device due to the heat generated by the power amplifying means can also be reduced.
[0020]
In particular, by grouping the antenna elements so that the distribution ratio of the variable power divider is 3 dB or more, it is possible to minimize an increase in the rated output of the power amplifying means when only one antenna element is driven. it can.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Generally, in a broadcasting satellite, a side lobe level outside a service area is specified in order to avoid interference with other countries, and it is necessary to suppress the side lobe level below a rule. FIG. 3 shows an example of the excitation amplitude distribution of the feeding array antenna when a radiation pattern that uniformly covers a service area (here, nationwide) is formed in a phased array antenna for a variable beam pattern broadcasting satellite. The numbers (1 to 173) in FIG. 3 are for distinguishing antenna elements. In FIG. 3, the antenna elements in the top row are numbered 1, 2, 3, 4, 5 from the left, and the next row has 6, 7, 8, 9, 10, 11 from the left. The following lines are similarly numbered, and the bottom line is numbered 171, 172, 173 from the left.
[0022]
In this case, the number of antenna elements is 173, and the antenna elements are arranged in a shape corresponding to the service area in Japan. The excitation amplitude values are represented by red for -3 dB to 0 dB, orange for -6 dB to -3 dB, yellow for -9 dB to -6 dB, and blue for -9 dB or less. Here, the amplitude value is normalized by the maximum excitation amplitude value. Although the colors are not shown in FIG. 3 attached to this specification, many red antenna elements are distributed in the center in the original of FIG. 3, and many blue antenna elements are distributed in the peripheral part. Orange and yellow antenna elements are distributed in the middle part (the same applies to FIGS. 5 and 6 described later).
[0023]
From FIG. 3, the excitation amplitude distribution of the feed array antenna decreases from the center of the array to the periphery, and the antenna element at the center of the array contributes more to the formation of the radiation pattern (the distribution of red and orange colors increases). Also, it can be seen that the excitation amplitude value of the antenna element around the feeding array antenna is small (the blue distribution is large). Particularly, the peripheral antenna element contributes to suppression of the side lobe level outside the area in the radiation pattern.
[0024]
FIG. 4 shows a nationwide uniform radiation pattern and a radiation pattern when the number of blue antenna elements is reduced. FIG. 4A shows a nationwide uniform radiation pattern, and FIG. 4B shows a radiation pattern when there is no peripheral element. As a result, when the number of blue antenna elements (antenna elements distributed largely in the periphery of FIG. 3) decreases, the shape of the nationwide beam is deformed in the frame 17 shown in FIG. It can be seen that this occurs. Also, it can be seen that the fluctuation of the gain in the nationwide beam is large within the frame 18 shown in FIG. Therefore, the peripheral antenna element has a small excitation amplitude value, but contributes to formation of a radiation pattern.
[0025]
However, in this example, the excitation amplitude values of red and blue differ by almost 10 dB, and even if the excitation amplitude values of blue and red are added, the power increase of the red antenna element is at most about 10%.
[0026]
The method of designing the radiation pattern is described in detail in Non-Patent Document 1, and will not be described here.
[0027]
FIG. 5 is an excitation amplitude distribution of the feeding array antenna when the entire service area (Japan) is irradiated with uniform radiation power and the radiation power in only the rainfall area (here, Sapporo) is increased.
[0028]
As can be seen from this figure, the entire excitation amplitude distribution of the feed array antenna is not much different from that in FIG. 3 (uniform in Japan), and the antenna element at the center of the array has a larger contribution to radiation pattern formation. . However, the red or orange amplitude distribution has changed above the power supply array corresponding to Sapporo forming the intensifying beam. However, these are not much different from the red and orange distributions in FIG. In other words, most of the antenna elements in the center and upper part of the array are red or orange and contribute to the formation of the radiation pattern, while almost all the antenna elements in the peripheral part are blue and contribute to the suppression of the side lobe level. Is the same as in the case of FIG.
[0029]
FIG. 6 is an excitation amplitude distribution of the feeding array antenna when the radiation power in the rainfall region (here, Okinawa) is increased as in FIG.
[0030]
It can also be seen from this figure that the entire excitation amplitude of the feed array antenna is not much different from that of FIG. 3 (uniform in Japan). However, the excitation amplitude distribution of red or orange below the feed array corresponding to Okinawa forming the intensified beam has changed. However, similarly to FIG. 3, the tendency that the excitation amplitude distributions of red and orange are biased toward the center of the array and the excitation amplitude distribution of blue is biased toward the periphery remains unchanged.
[0031]
As described above, the excitation amplitude distribution of the feed array antenna element is large at the center of the feed array both when the entire service area (Japan) is irradiated with uniform radiated power and when the radiated power is increased only in the rainfall area. It can be seen that the tendency of becoming smaller at the periphery does not change.
[0032]
That is, according to the tendency of the excitation amplitude distribution of the feeding array antenna element, the array antenna element is divided into an antenna element having a large excitation amplitude value at the center (the excitation amplitude value is red or orange) and an excitation amplitude value at the peripheral part. Antenna elements that are small (the excitation amplitude values are yellow and blue and are 3 dB or less smaller than the excitation amplitude value at the center) are combined and grouped, and each group is respectively connected to one power amplifier via a variable power distributor. By connecting, the number of power amplifiers can be reduced.
[0033]
FIG. 7 is a diagram showing an example of a grouping result of antenna elements in a phased array antenna mounted on a variable beam pattern broadcasting satellite according to an embodiment of the present invention, and FIG. 8 is a diagram illustrating a variable beam pattern according to an embodiment of the present invention. It is a figure for explaining the schematic structure of the phased array antenna feeder for beam pattern broadcasting satellite loading.
[0034]
The variable beam pattern of the present embodiment shown in FIG. 8 is an example of a configuration based on the grouping shown in FIG. 7, and the conventional variable beam pattern shown in FIG. It has the same configuration as the phased array antenna for broadcasting satellites.
[0035]
In the grouping shown in FIG. 7, the excitation amplitude value is red of -3 dB to 0 dB or orange of -6 dB to -3 dB (the amplitude excitation value is large) in accordance with the antenna element number of FIG. The center antenna element and the excitation amplitude value is -9 dB to -6 dB yellow or -9 dB or less blue (the amplitude excitation value is smaller than the center antenna element), and contributes to side lobe level suppression And surrounding antenna elements are grouped in pairs. In FIG. 7, “antenna element number” is the antenna element number in FIG. 3, “Sapporo excitation amplitude” is the color of the antenna element of the excitation amplitude distribution in FIG. 5, and “Okinawa excitation excitation amplitude” is the excitation amplitude in FIG. The colors of the distributed antenna elements are shown. For each group, the excitation amplitude was "red and blue" or "orange and blue" or "yellow and blue" or "yellow and yellow" both when the intensified beam was formed in Sapporo and when the intensified beam was formed in Okinawa. It is a combination of Note that the colors of the antenna elements shown in FIG. 7 indicate the excitation amplitude values of the power supplied to each antenna element as described above. Red represents -3 dB to 0 dB, orange represents -6 dB to -3 dB, and yellow represents-. 9 dB to -6 dB, and blue indicates -9 dB or less.
[0036]
That is, in the present embodiment, the excitation amplitude value that is excited by the antenna element of the phased array antenna mounted on the variable beam pattern satellite that compensates for the radio wave attenuation due to rainfall forms an intensified beam for compensating the radio wave attenuation. Depending on the area, an antenna element arranged at the center and having a large excitation amplitude value (having a large contribution to radiation pattern formation and having an excitation amplitude value of- An antenna element having a red color of 3 dB to 0 dB or an orange color of -6 dB to -3 dB) and an antenna element arranged at the periphery and having a small excitation amplitude value (contribution to formation of a radiation pattern is small and the excitation amplitude value is -9 dB to- (An antenna element that is yellow at 6 dB or blue at -9 dB or less and has an excitation amplitude value at least 3 dB smaller than the antenna element at the center) The has a configuration in which a combined group one by one each of a plurality of form. For example, the first group has a configuration in which the # 1 antenna element whose excitation amplitude value is blue at the time of Sapporo boost and Okinawa boost is combined with the # 13 antenna element which is red at the time of Sapporo boost and yellow at the time of Okinawa boost. . Also, as is apparent from FIG. 7, in the present embodiment, the first to 86th groups are formed by combining all the antenna elements.
[0037]
As shown in FIG. 8, in the phased array antenna mounted on a variable beam pattern broadcasting satellite according to the present embodiment, the output of the distributor 6 includes an attenuator (denoted as ATT in the drawing) 7, a power amplifier 8, and a variable power distribution unit. The antenna elements 11 are connected to the output of the variable power distributor 9 via the phase shifter 10 in this order. A control signal from the amplitude / phase control unit 12 is input to the attenuator 7, the variable power distributor 9, and the phase shifter 10.
[0038]
As described above, in the phased array antenna for mounting on a variable beam pattern broadcast satellite according to the present embodiment, one group is formed by the two antenna elements 11, and the attenuator 7, the power amplifier 8, and the variable power distribution are provided for each group. Since the devices 9 are arranged, the feed power for each antenna element 11 is obtained from the variable power distributor 9. Therefore, in the present embodiment, the phase shifter 10 is arranged for each output of the variable power distributor 9 so as to give a desired excitation amplitude to the supply power amplified and output from the variable power distributor 9. .
[0039]
Next, the operation of the phased array antenna power supply device for mounting on a variable beam pattern broadcasting satellite according to the present embodiment will be described with reference to FIG. In the phased array antenna power supply device mounted on a variable beam pattern broadcasting satellite according to the present embodiment, the received signal received by the receiving antenna 1 is band-limited by a BPF (bandpass filter) 2 corresponding to the channel, and then the LNA (low (A noise amplifier) 3. The amplified received signal is converted to a transmission frequency by the frequency converter 4, amplified by the amplifier 5 for compensating for equipment loss and distribution loss in the distributor 6, and input to the distributor 6.
[0040]
The signal input to the distributor 6 is distributed to each group shown in FIG. 7, and is input to the attenuator 7 for each group. Here, in the present embodiment, one group is constituted by the two antenna elements 11, so that the attenuation value in each attenuator 7, that is, the control of the excitation amplitude by the attenuator 7 and the power amplifier 8 in the subsequent stage is controlled by each group. Is controlled so as to have the excitation amplitude of the two antenna elements 11. For example, at the time of Sapporo boosting of the first group including the antenna elements 11 of # 1 and # 13, the excitation amplitude of the antenna element 11 of # 1 is blue (-9 dB or less), and the excitation of the antenna element 11 of # 13 is excited. Since the amplitude becomes red (−3 dB to 0 dB), the attenuator 7 is controlled so that the output signal from the power amplifier 8 has an amplitude value obtained by adding the respective excitation amplitudes. In the other groups, similarly to the first group, the attenuation value of the attenuator 7 is controlled so that the excitation amplitude becomes the sum of the excitation amplitudes of the two antenna elements 11. In the phased array antenna mounted on a variable beam pattern broadcasting satellite according to the present embodiment, the compensation of the distribution loss by the variable power distributor 9 is performed by either the amplifying means including the attenuator (ATT) 7 and the power amplifier 8 or the amplifier 5. Needless to say, the compensation may be made.
[0041]
The signal controlled to have a predetermined excitation amplitude by the power amplifier 8 is divided into two by a variable power distributor 9 provided for each group, and then the excitation phase is controlled by a phase shifter 10 to control each antenna element 11. Powered. The attenuator 7, the variable power distributor 9, and the phase shifter 10 are controlled by an amplitude / phase controller 12.
[0042]
As described above, in the phased array antenna mounted on a variable beam pattern broadcasting satellite according to the present embodiment, the amplitude / phase control unit 12 adjusts the attenuation value of the attenuator 7 so that the phased array antenna forms a desired antenna pattern. The distribution amplitude of the variable power distributor 9 is adjusted to set the excitation amplitude value, and the phase shifter 10 connected in front of the antenna element 11 is set to the desired excitation phase value. With such a configuration, a phased array antenna power supply device in which the power amplifier 8 is reduced by combining the antenna element 11 having a large excitation amplitude value and the antenna element 11 having a small excitation amplitude value than the antenna element 11 is provided. It can be formed.
[0043]
In the present embodiment, the configuration in which two antenna elements 11 are assigned to one power amplifier 8, that is, the grouping of the antenna elements 11 is a pair, but the present invention is not limited to this. By adopting a power amplifier 8 having a large rated output, the antenna elements 11 can be grouped into groups of three or four.
[0044]
As described above, the invention made by the inventor has been specifically described based on the embodiment of the present invention. However, the present invention is not limited to the embodiment of the present invention, and does not depart from the gist of the invention. It goes without saying that various changes can be made in.
[0045]
【The invention's effect】
The following is a brief description of an effect obtained by a representative one of the inventions disclosed in the present application.
[0046]
By applying the grouping of the antenna elements using the feed array antenna excitation amplitude distribution at the design stage, a plurality of feed array antenna elements can be connected to one power amplifier. As a result, the size of the power supply circuit is reduced, and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a configuration example of a conventional phased array antenna mounted on a variable beam pattern broadcasting satellite.
FIG. 2 is a conceptual diagram of a configuration example of a conventional phased array antenna mounted on a variable beam pattern broadcasting satellite.
FIG. 3 is a photograph of a simulation result of an excitation amplitude distribution of a feed array antenna when the entire Japan is irradiated with uniform radiation power. Note that each amplitude value is normalized by the maximum excitation amplitude value.
4 is a photograph of a simulation result of a nationwide uniform radiation pattern in the excitation amplitude distribution shown in FIG. 3 and a radiation pattern without peripheral elements.
FIG. 5 is a photograph of a simulation result of a feed array antenna excitation amplitude distribution when radiating power is increased only in a rainfall region while irradiating the whole of Japan with uniform radiating power. Here, the rainfall area is Sapporo.
FIG. 6 is a photograph of a simulation result similar to that of FIG. 5, where the rainfall area is Okinawa.
FIG. 7 is a part of an example in which two antenna elements are grouped into one using the present invention.
FIG. 8 is a conceptual diagram of a configuration example of a grouped variable beam pattern broadcasting satellite phased array antenna feed circuit according to the present invention.
[Explanation of symbols]
1: receiving antenna 2: BPF (bandpass filter)
REFERENCE SIGNS LIST 3 LNA (low noise amplifier) 4 frequency converter 5 amplifier 6 13 distributor 7 attenuator (ATT) 8 power amplifier 9 variable power distributor 10 phase shifter 11 antenna element 12 amplitude・ Phase control unit 14 ... Excitation amplitude / Phase control unit 15 ... Reflector 16 ... Fed array antenna

Claims (4)

A phased array antenna feeding device that feeds power to a plurality of antenna elements constituting a phased array antenna for a satellite,
Power amplifying means less than the number of the antenna elements for supplying power to each group in which the plurality of antenna elements are grouped,
A variable power divider that distributes the output of the power amplifying means to each antenna element in the group so that the power can be distributed.
A phased array antenna feeding device, comprising: The phased array antenna feeding device according to claim 1,
The said variable power distributor has a group which makes a distribution ratio variable at 3 dB or more, The phased array antenna feed apparatus characterized by the above-mentioned. A phased array antenna system for use on a satellite,
A plurality of antenna elements,
Power amplifying means less than the number of the antenna elements for supplying power to each group in which the plurality of antenna elements are grouped,
A variable power divider that distributes the output of the power amplifying means to each antenna element in the group so that the power can be distributed.
A phased array antenna system comprising: A variable beam pattern broadcast satellite capable of forming an intensified beam,
A plurality of antenna elements constituting a phased array antenna,
Power amplifying means less than the number of the antenna elements for supplying power to each group in which the plurality of antenna elements are grouped,
A distributor that distributes a reception signal received by a reception antenna to the power amplification unit,
A variable power divider that distributes the output of the power amplifying means to each antenna element in the group so that the power can be distributed.
A variable beam pattern broadcasting satellite, comprising:

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