JP4199521B2 - Active phased array antenna for satellite installation - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a traveling wave tube amplifier, and more particularly to a traveling wave tube amplifier capable of controlling the phase shift of an output signal.
[0002]
[Prior art]
Conventionally, as shown in FIG. 7, a traveling wave tube including a hot cathode 101, a heater 102, an anode 103, a helix (slow wave circuit) 104, an input circuit 105, an output circuit 106, and a collector 107, and the traveling wave tube A traveling wave tube amplifier 100 including a traveling wave tube power source 110 having a plurality of high voltage power sources for supplying an operating voltage to each electrode is known.
[0003]
Here, the heater voltage Vf is a voltage for heating the heater 102, the anode voltage Va is a voltage for accelerating the electron beam between the hot cathode 101 and the anode 103, and the helix voltage Vhel is between the hot cathode 101 and the helix 104. The voltage for accelerating the electron beam and the collector voltage Vc are voltages for capturing the electron beam.
[0004]
As shown in FIG. 8, the general high-frequency characteristics of this type of traveling wave tube amplifier are that the output power is saturated when a certain input power is exceeded, resulting in a decrease in gain and power efficiency. And the output signal has a large phase difference.
[0005]
For this reason, in the conventional traveling wave tube amplifier, the voltage supplied to each electrode of the traveling wave tube is set so that the maximum power efficiency can be obtained at the required output power.
[0006]
When synthesizing the output power of a plurality of traveling wave tube amplifiers in order to supply large power using such traveling wave tube amplifiers, it is difficult to align the phases of the outputs of the traveling wave tube amplifiers. Therefore, as shown in FIG. 9, a phase shifter 120 for changing the phase of the output of each traveling wave tube amplifier 100 is installed, and the phase shift amount control unit 130 controls each phase shifter 120 so that the phase is in phase. It is necessary to synthesize the outputs of the traveling wave tube amplifiers 100 by the output synthesizer 140.
[0007]
Further, when an active phased array antenna that can freely control directivity using a traveling wave tube amplifier is configured, as shown in FIG. 10, the output phase of each traveling wave tube amplifier 100 serving as an antenna element is controlled. The phase shifter 120 is installed, and each phase shifter 120 is controlled by the phase shift amount control unit 130 to control the directivity (see, for example, Patent Document 1).
[0008]
[Patent Document 1]
JP-A-7-321537 (FIGS. 1 and 6)
[0009]
[Problems to be solved by the invention]
However, in such a conventional traveling wave tube amplifier, when the output power of the traveling wave tube amplifier as shown in FIG. 9 is synthesized, an active phased array antenna as shown in FIG. In the case of using a tube amplifier, a phase shifter must be installed for each traveling wave tube amplifier, which increases the cost.
[0010]
Moreover, in order to control the directivity more precisely, particularly in active phased array antennas, it is necessary to install a phase shifter (infinite phase shifter) capable of finely controlling the phase for each antenna element. There is a problem that the cost increases and the loss of output power due to the insertion of the phase shifter also increases.
[0011]
Therefore, the present invention has an object to enable the phase of an output signal of a traveling wave tube amplifier to be variable by controlling the operation of the traveling wave tube amplifier without installing a phase shifter in the traveling wave tube amplifier. To do.
[0012]
[Means for Solving the Problems]
As means for solving the above-mentioned problems, the present invention provides an active phased array for mounting on a satellite that is divided into a plurality of inputs, each of which is connected to a traveling wave tube amplifier and a radiating element, and operates as one transmitter as a whole. an antenna, by changing the voltage supplied to the slow wave circuit of the traveling-wave tube amplifier, a variable voltage source for controlling the phase of the output signal, changing the voltage supplied to the anode of the traveling wave tube amplifier Thus, there is provided an anode variable voltage source that compensates for a decrease in output power caused by the phase control.
[0013]
Thereby, the voltage supplied to the low-speed wave circuit is changed, and the phase of the output signal is changed. Therefore, since the phase of the output signal is controlled without using a phase shifter or the like, loss of output power due to insertion of the phase shifter can be suppressed. Further, by changing the voltage supplied to the anode of the traveling wave tube amplifier, it is possible to compensate for the decrease in output power caused by the phase control, so that power can be supplied stably.
[0014]
A cavity coupling type is used for the slow wave circuit, and the body voltage supplied to the cavity coupling unit is changed by the variable voltage source, or a helix type is used for the slow wave circuit, and the variable voltage source It is preferable to change the helix voltage supplied to the helix portion.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described below with reference to the drawings.
[0018]
FIG. 1 is a diagram showing a traveling wave tube amplifier according to a first embodiment (reference example) of the present invention. In the present embodiment, a helix traveling wave tube amplifier using a helix in a slow wave circuit is shown.
[0019]
In FIG. 1, a traveling wave tube amplifier 1 according to this embodiment includes a hot cathode 11, a heater 12, an anode 13, a helix (slow wave circuit) 21, an input circuit 22, an output circuit 23, and a collector unit 30. A traveling wave tube having a tube, a heater voltage source 71 for supplying a heater voltage, an anode voltage source 72 for supplying an anode voltage, a helix variable voltage source 73 for variably supplying a helix voltage, and a collector voltage source 74 for supplying a collector voltage And a power source 70.
[0020]
FIG. 2 is a diagram showing the structure of a helical traveling wave tube. As shown in FIG. 2, the helical traveling wave tube includes an electron gun unit 10 that emits electrons, a high-frequency circuit unit 20 that processes microwaves, a collector unit 30 that captures electrons, and an electron beam that focuses the electron beam. A focusing device section 40 and a package 50 for supporting the main body and radiating heat are provided.
[0021]
The electron gun unit 10 includes a hot cathode 11 that emits electrons and a heater 12 that heats the hot cathode 11.
[0022]
The high-frequency circuit unit 20 includes a helix 21 that causes the microwave and the electron beam to interact, an input circuit 22 that inputs the microwave, and an output circuit 23 that outputs the amplified microwave.
[0023]
The collector unit 30 includes a plurality of electrodes 31. The electron beam focusing device section 40 includes a plurality of magnets 41 and magnetic poles 42 that generate a magnetic field in the electron beam path.
[0024]
The electron gun unit 10 and the collector unit 30 are connected by a cylindrical metal container 60, and the inside of the collector unit 30 is kept in vacuum from the inside of the electron gun unit 10 through the metal container 60. A helix 21 in which a metal ribbon or wire is spirally wound is fixed by a support rod, and an electron beam focusing device section 40 is provided around the metal container 60.
[0025]
In such a helix traveling wave tube, electrons are emitted from the hot cathode 11 of the electron gun unit 10 in a vacuum and accelerated at a high voltage of several kV or more, and at the same time, a magnetic field formed by the electron beam focusing device unit 40. It is focused by.
[0026]
The focused electrons form a thin electron beam and pass inside the helix 21 helix.
[0027]
On the other hand, after the microwave is guided from the input circuit 22 into the traveling wave tube, it travels along the helix 21 from the upstream side (the hot cathode 11 side) of the electron beam, and its axial velocity is substantially synchronized with the velocity of the electron beam. When this occurs, an interaction occurs between the electron beam and the microwave, and the power of the microwave is amplified.
[0028]
The amplified microwave is extracted from the output circuit 23 connected to the helix 21.
[0029]
Further, the electron beam that has finished the interaction with the microwave collides with and is captured by the collector section 30 including the three- and four-stage electrodes 31 having different potentials, and the kinetic energy of the electrons is converted into thermal energy.
[0030]
Here, the electron beam velocity v at the helix 21 is simply 1/2 · m · v ² = e · V to v = (2 · e / m · V) ^1/2.
Can be calculated. Here, m is the mass of the electron, e is the elementary charge of the electron, and V is the helix voltage.
[0031]
That is, it can be seen that the electron beam velocity can be controlled by changing the helix voltage.
[0032]
From this relationship, it can be seen that when the helix voltage is increased, the electron beam speed is increased, so that the phase of the output signal is advanced, and when the helix voltage is decreased, the electron beam speed is decreased, so that the phase of the output signal is delayed.
[0033]
That is, it is possible to control the phase of the output signal while maintaining the amplification effect on the microwave by changing the helix voltage within the range of the helix voltage where the interaction between the electron beam and the microwave does not change significantly.
[0034]
FIG. 3 shows the change in the output phase when only the helix voltage is lowered from the saturation operation state by actually using the Ku-band helix traveling wave tube amplifier.
[0035]
Here, the measurement was performed by changing the helix voltage (6.757 kV) during the saturation operation from the voltage (6.6 kV), which is a little lower than 2%.
[0036]
When the voltage is reduced by more than 2%, the output power is 0.25dB (52.4dB is 52.15dB) and the power efficiency is 2.4% (62.7% is 60.3%). Was found to change significantly with a 93 ° delay (-50 ° to -143 °).
[0037]
From this measurement result, it is confirmed that the output phase is delayed as the helix voltage is lowered, and by controlling the helix voltage, the phase of the output signal can be changed without substantially degrading the output power and power efficiency. Proven to be possible.
[0038]
Therefore, in the traveling wave tube amplifier 1 of the present embodiment, the helix variable voltage source 73 is used to supply the helix voltage, the helix voltage is changed within a range in which the interaction between the electron beam and the microwave does not change greatly, and the output The phase of the signal was controlled.
[0039]
As described above, in the present embodiment, the helix variable voltage source 73 that variably supplies the helix voltage is provided, and the helix voltage is changed by the helix variable voltage source 73, so that the output power and the power efficiency are hardly deteriorated. The phase of the signal can be controlled.
[0040]
In the present embodiment, a helix traveling wave tube amplifier using a helix in the slow wave circuit is shown, but the cavity coupled traveling wave tube amplifier using a cavity coupled type in the slow wave circuit also has its cavity. The same effect can be obtained by changing the body voltage supplied to the coupling portion.
[0041]
Next, FIG. 4 is a diagram showing a traveling wave tube amplifier according to a second embodiment (reference example) of the present invention. In addition, since this embodiment is comprised substantially the same as the said 1st Embodiment, it attaches | subjects the same code | symbol to the same structure, and demonstrates only a characteristic part.
[0042]
As shown in FIG. 4, the traveling wave tube power supply 80 of the present embodiment includes an anode variable voltage source 81 that variably supplies an anode voltage. When the anode voltage is increased by the anode variable voltage source 81, the cathode current, that is, the amount of emitted electrons increases, and the output power increases. On the other hand, when the anode voltage is lowered, the cathode current, that is, the amount of emitted electrons decreases, and the output power decreases.
[0043]
For this reason, in the traveling wave tube amplifier 2 of this embodiment, as in the above-described embodiment, a slight decrease in output power that occurs when the helix voltage is changed by the helix variable voltage source 73 and the phase of the output signal is controlled. This can be compensated by increasing the anode voltage by the anode variable voltage source 81 to increase the amount of emitted electrons.
[0044]
This is effective when a traveling wave tube amplifier is used for an active phased array antenna and a slight drop in the output voltage caused by changing the helix voltage affects the directivity control of the active phased array antenna. is there.
[0045]
As described above, in the present embodiment, the output power is controlled by changing the anode voltage by the anode variable voltage source 81 to compensate for the reduction in output power that occurs when the helix voltage is changed to control the phase of the output signal. be able to.
[0046]
Next, FIG. 5 is a diagram showing a power combiner of a third embodiment (reference example) of the present invention. Since the present embodiment is a power combiner using the traveling wave tube amplifier 1 of the first embodiment, description will be given with reference to FIG.
[0047]
As shown in FIG. 5, the power combiner of the present embodiment controls a plurality of traveling wave tube amplifiers 1 and helix variable voltage sources 73 of the plurality of traveling wave tube amplifiers 1 to supply each traveling wave tube amplifier 1. A voltage control unit 3 that controls the helix voltage to be output, and an output synthesizer 4 that synthesizes outputs of the plurality of traveling wave tube amplifiers 1
[0048]
In such a power combiner, the voltage controller 3 controls the helix voltage supplied to each traveling wave tube amplifier 1 by the helix variable voltage source 73 to make the phase of the output signal of each traveling wave tube amplifier 1 in phase. .
[0049]
The output signals of the traveling wave tube amplifiers 1 in phase are synthesized by the output synthesizer 4 and output as a high power signal.
[0050]
Thus, in this embodiment, the voltage control unit 3 controls the helix variable voltage source 73 of the traveling wave tube amplifier 1 so that the phase of the output signal of each traveling wave tube amplifier is in phase. The variable power source required for 73 can be introduced at a lower cost than the phase shifter, and the cost can be reduced.
[0051]
Next, FIG. 6 is a figure which shows the active phased array antenna of 4th Embodiment of this invention. Since the present embodiment is an active phased array antenna using the traveling wave tube amplifier 1 of the first embodiment described above, FIG.
[0052]
As shown in FIG. 6, the active phased array antenna of the present embodiment is divided into a plurality of inputs, and controls a plurality of traveling wave tube amplifiers 1 and a helix variable voltage source 73 of the plurality of traveling wave tube amplifiers 1. Each of the traveling wave tube amplifiers 1, and a radiating element 6 connected to the output of each traveling wave tube amplifier 1. 6 are arranged close to each other and operate as one transmission apparatus as a whole. The radiating element 6 is preferably a horn antenna for use on a satellite.
[0053]
In such an active phased array antenna, the voltage control unit 5 controls the helix voltage supplied to each traveling wave tube amplifier 1 by the helix variable voltage source 73 and outputs the output signal of each traveling wave tube amplifier 1 serving as an antenna element. The phase can be controlled and the directivity of the active phased array antenna can be controlled.
[0054]
Thus, in this embodiment, the voltage control unit 5 controls the helix variable voltage source 73 of the traveling wave tube amplifier 1 to control the phase of the output signal of each traveling wave tube amplifier. The variable power source required for the source 73 can be introduced at a lower cost than the phase shifter, and the cost can be reduced.
[0055]
In addition, since the degradation of the power efficiency when the helix voltage of the traveling wave tube amplifier 1 is changed is smaller than the loss of power due to the insertion of the phase shifter, it is particularly mounted on the satellite station that uses the limited generated power of the satellite. This is more effective in an active phased array antenna for use.
[0056]
【The invention's effect】
According to the present invention, since the phase of the output signal is controlled by changing the voltage supplied to the low-speed wave circuit by the variable voltage source, the phase of the output signal can be controlled without installing a phase shifter or the like. And cost can be reduced.
[0057]
Here, as a slow wave circuit, a cavity coupling type or a helix type is conceivable. In the cavity coupling type, the body voltage supplied to the cavity coupling part may be changed, and in the helix type, the helix voltage supplied to the helix part. It is good to change.
[0058]
Moreover, if the voltage supplied to the anode is changed by the anode variable voltage source that changes the voltage supplied to the anode to control the power of the output signal, the decrease in output power caused by changing the phase can be compensated. Can do.
[Brief description of the drawings]
FIG. 1 is a diagram showing a traveling wave tube amplifier according to a first embodiment of the present invention, and is a schematic configuration diagram thereof.
FIG. 2 is a cross-sectional view showing the traveling wave tube.
FIG. 3 is a diagram showing a change in output phase due to a change in helix voltage.
FIG. 4 is a diagram showing a traveling wave tube amplifier according to a second embodiment of the present invention, and is a schematic configuration diagram thereof.
FIG. 5 is a diagram showing a power combiner according to a third embodiment of the present invention, and is a schematic configuration diagram thereof.
FIG. 6 is a diagram showing an active phased array antenna according to a fourth embodiment of the present invention, and is a schematic configuration diagram thereof.
FIG. 7 is a schematic configuration diagram of a conventional traveling wave tube amplifier.
FIG. 8 is a diagram showing high-frequency characteristics of a conventional traveling wave tube amplifier.
FIG. 9 shows a conventional power combiner.
FIG. 10 is a diagram showing a conventional active phased array antenna.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 2 Traveling-wave tube amplifier 3 Voltage control part 4 Output synthesizer 5 Voltage control part 6 Radiation element 10 Electron gun part 11 Thermal cathode 12 Heater 13 Anode 20 High frequency circuit part 21 Helix (slow wave circuit)
22 Input circuit 23 Output circuit 30 Collector section 31 Electrode 40 Electron beam focusing apparatus section 41 Magnet 42 Magnetic pole 50 Package 60 Metal container 70 Traveling wave tube power supply 71 Heater voltage source 72 Anode voltage source 73 Helix variable voltage source 74 Collector voltage source 80 Progress Wave tube power supply 81 Anode variable voltage source 100 Traveling wave tube amplifier 101 Thermal cathode 102 Heater 103 Anode 104 Helix (slow wave circuit)
105 input circuit 106 output circuit 107 collector 110 traveling wave tube power supply 120 phase shifter 130 phase shift amount control unit 140 output synthesizer

Claims (3)

An active phased array antenna mounted on a satellite that is divided into a plurality of inputs, each of which is connected to a traveling wave tube amplifier and a radiating element, and operates as a single transmitter as a whole,
A variable voltage source that controls the phase of the output signal by changing the voltage supplied to the slow wave circuit of the traveling wave tube amplifier;
An active variable voltage source for satellite installation, comprising: an anode variable voltage source that compensates for a decrease in output power caused by controlling the phase by changing a voltage supplied to an anode of the traveling wave tube amplifier. Array antenna.   The satellite-mounted active phased array antenna according to claim 1, wherein the low-speed wave circuit is of a cavity coupling type, and a body voltage supplied to the cavity coupling portion is changed by the variable voltage source.   The satellite-mounted active phased array antenna according to claim 1, wherein the low-speed wave circuit is a helix type, and the helix voltage supplied to the helix portion is changed by the variable voltage source.

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