JP7531418B2 - Electromagnetic wave amplifier and radar device equipped with electromagnetic wave amplifier - Google Patents

Description

The disclosed technology relates to an electromagnetic wave amplifier that amplifies high-frequency signals that become electromagnetic waves.

Traditionally, gyrotrons, klystrons, and traveling wave tubes (hereinafter referred to as "gyrotrons, etc.") have been used in devices to amplify high-frequency signals or electromagnetic waves in the gigahertz or terahertz range.

Prior art discloses a gyrotron that has a cylindrical oscillator tube with a vacuum inside and is capable of generating low-power or small-sized, high-output millimeter waves (for example, Patent Document 1). The electromagnetic wave amplification operation of prior art, including the amplification operation of the gyrotron, is based on the action of electrons in an electron beam flowing through a vacuum, whereas the amplification operation of the electromagnetic wave amplifier according to the disclosed technology is based on the action of three magnetic fields that are generated in three different ways based on a novel idea, and there is no similar prior art. For convenience, Patent Document 1 relating to the gyrotron is shown here.

JP 2006-278285 A

Providing a container that maintains a vacuum inside an electromagnetic wave amplifier has been an obstacle to making electromagnetic wave amplifiers smaller and less expensive. For example, when designing an electromagnetic wave amplifier for an in-vehicle radar device, there is a demand for an electromagnetic wave amplifier that does not require a container that maintains a vacuum inside.

The disclosed technology aims to solve the above problems and provide an electromagnetic wave amplifier that does not require a container to keep the inside vacuum, which was essential in the signal amplification section of conventional gyrotrons and other devices.

The electromagnetic wave amplifier of the disclosed technology includes, from the inside, a central conductor, a tubular conductor, and a magnetic field generating unit, wherein the central conductor has an axial shape and is arranged in the center of the tubular conductor and passes a current in the longitudinal direction of the axis of the tubular conductor , a magnetic field is applied to the tubular conductor in the longitudinal direction of the axis by the magnetic field generating unit arranged on the outer periphery, a first resultant magnetic field swirling in a spiral shape is generated outside the tubular conductor, an AC signal current whose polarity alternates sequentially proceeds through the tubular conductor as a path through the first resultant magnetic field, a signal magnetic field whose polarity alternates alternately in the rotational direction emitted by the signal current proceeds through the first resultant magnetic field, the first resultant magnetic field and the signal magnetic field are combined to generate a second resultant magnetic field, and the second resultant magnetic field generates an electromotive force in the longitudinal direction of the axis of the tubular conductor, acting to increase the signal current.

The electromagnetic wave amplifier according to the disclosed technology has the above configuration, and is therefore capable of amplifying high-frequency signals that become electromagnetic waves without requiring a container that maintains a vacuum inside.

FIG. 1 is an explanatory diagram showing the mechanism of a conventional gyrotron. FIG. 2 is an explanatory diagram showing a signal current and a magnetic field propagating through a waveguide of a conventional gyrotron. FIG. 3 is an explanatory diagram showing a composite magnetic field in a signal amplifier of a conventional gyrotron. FIG. 4 is an explanatory diagram showing a schematic configuration and an operation principle of the electromagnetic wave amplifier according to the first embodiment. FIG. 5 is a diagram supplementing the configuration of the permanent magnet type electromagnetic wave amplifier. FIG. 6 is a diagram supplementing the configuration of a multiple magnet type electromagnetic wave amplifier. FIG. 7 is a diagram supplementing the configuration of the electromagnet type electromagnetic wave amplifier. FIG. 8 is an explanatory diagram showing a first example of a configuration in which a coaxial cable is connected to the electromagnetic wave amplifier according to the first embodiment. FIG. 9 is an explanatory diagram showing a second configuration example in which a coaxial cable is connected to the electromagnetic wave amplifier according to the first embodiment. FIG. 10 is a schematic diagram showing a basic configuration of an electromagnet-type electromagnetic wave amplifier according to the first embodiment. FIG. 11 is a schematic diagram showing a first modified example of the electromagnet type electromagnetic wave amplifier according to the first embodiment. FIG. 12 is a schematic diagram showing a second modified example of the electromagnet type electromagnetic wave amplifier according to the first embodiment. FIG. 13 is an explanatory diagram showing a first example of the configuration of the electromagnetic wave amplifier according to the second embodiment. FIG. 14 is an explanatory diagram showing a second configuration example of the electromagnetic wave amplifier according to the second embodiment. FIG. 15 is an explanatory diagram showing a configuration example of an electromagnetic wave amplifier according to the third embodiment. FIG. 16 is an explanatory diagram showing a configuration example in which a coaxial cable is connected to an electromagnetic wave amplifier according to the third embodiment. FIG. 17 is an explanatory diagram showing a configuration example of a microstructure electromagnetic wave amplifier according to the fourth embodiment. FIG. 18 is a diagram showing the configuration of an amplification waveguide according to the fourth embodiment. FIG. 19 is a configuration diagram showing a modified example of the amplification waveguide according to the fourth embodiment. FIG. 20 is a schematic diagram of an electromagnetic wave amplifier using multiple microstructured amplification waveguides. FIG. 21 is an explanatory diagram illustrating a method for connecting a plurality of amplification waveguides having a microstructure.

The electromagnetic wave amplifier 100 according to the disclosed technology will be explained below by dividing it into the following embodiments. The following description provided before the explanation of the embodiments provides a brief explanation of the operation of a conventional gyrotron, and makes clear the differences between the gyrotron according to the conventional technology and the electromagnetic wave amplifier 100 according to the disclosed technology.

Description of the Prior Art
A typical explanation of the operating principle of a gyrotron or the like is premised on the presence of an electron beam in the center of the cavity, as described in, for example, paragraphs 0009-0011 and 0028 of Patent Document 1. Most explanations are vague, such as saying that the electron beam in the cavity bunches (hereinafter, "bunching"), and an "interaction" occurs with the signal current, amplifying the signal current.
The disclosed technology is based on a novel perspective that is completely different from conventional technology, in that the electron beam is a path for a current that generates a magnetic field around it, by reconsidering the "interaction" of the central electron beam. This novel concept, as described below, makes it possible to explain how the signal current is amplified by the behavior of three magnetic fields, including the magnetic field generated by the current flowing in the center, and also to explain the existence of an electromotive force added to the signal current and how energy is transferred from the central current to the signal current.

Figure 1 is an explanatory diagram showing the mechanism of a conventional gyrotron, focusing on the current (opposite the flow of the electron beam) that generates a magnetic field based on the concept of the disclosed technology, and shows the state of the magnetic field in the signal amplifier section. Figure 2 is an explanatory diagram showing the signal current and magnetic field propagating through the waveguide of a conventional gyrotron. Figure 3 is an explanatory diagram showing the composite magnetic field in the signal amplifier section of a conventional gyrotron. Note that in order to distinguish the conventional technology from the disclosed technology, the reference numbers for the components in the explanation of the conventional technology have the letter G added after the number to indicate that it is a conventional technology gyrotron.

As shown in FIG. 1, a conventional gyrotron includes a tubular conductor 110G through which a signal current flows, and a surrounding magnet that applies an axial magnetic field to the outer circumference of the tubular conductor 110G. A conventional gyrotron (also called an oscillator tube) is maintained in a vacuum inside. The inside of the oscillator tube is composed of an electron gun portion (not shown), a cavity portion (signal amplifier portion), and a collector portion (not shown). The electron gun is configured to heat the cathode with a filament or the like, and emits thermoelectrons. The emitted thermoelectrons are accelerated toward the anode by the electric field between the anode and the cathode. The accelerated thermoelectrons are focused into an electron beam by the magnetic field generated by the outer circumference surrounding magnet, and flow through the center of the cavity portion.

As shown in Figure 2, the tubular conductor 110G of the gyrotron can also be interpreted as a waveguide that propagates the signal current.

As shown in FIG. 3, when no signal current flows through the tubular conductor 110G, a spirally rotating composite magnetic field No. 1 is generated by the axial magnetic field generated by the surrounding magnet and the rotational magnetic field generated by the electron beam. This generated composite magnetic field No. 1 amplifies the signal current flowing through the tubular conductor 110G.

The principle by which the signal current is amplified will be explained below. As mentioned above, a spirally rotating composite magnetic field No. 1 is generated, and an AC signal current with sequentially alternating polarity travels through this spiral composite magnetic field No. 1. In other words, a signal magnetic field in which the direction of rotation emitted by the signal current alternates travels through the spiral composite magnetic field No. 1.

By adding this signal magnetic field to the axial magnetic field and the rotational magnetic field, as shown in FIG. 1, the spiral composite magnetic field #1 is combined into a wavy composite magnetic field #2 centered on the inner surface of the tubular conductor 110G. Here, the composite magnetic field #2 is synchronized with the progressing AC signal current. At the timing when the polarity of the signal current changes, the composite magnetic field #2 penetrates the tubular conductor 110G. At this timing, the composite magnetic field #2 has a magnetic field component normal to the surface of the tubular conductor 110G, and becomes a magnetic field perpendicular to the actual conductor when the signal current flows through the tubular conductor 110G.

In general, when a high-frequency signal current flows through the tubular conductor 110G, it is concentrated on the inner surface of the tubular conductor 110G due to the skin effect. In other words, the actual flow path of the signal current is the inner surface of the tubular conductor 110G. For this reason, it is important to pay attention to the second composite magnetic field that undulates in a wave-like manner centered on the inner surface of the tubular conductor 110G.

Since the composite magnetic field #1 rotates in a spiral shape, the portion where the composite magnetic field #2 penetrates the surface of the tubular conductor 110G moves across the direction of the signal current as it travels. In other words, the portion where the composite magnetic field #2 is normal to the surface of the tubular conductor 110G rotates in the circumferential direction of the tubular conductor 110G. In other words, the direction of the signal current (the direction in which the conductor is arranged), the normal component of the composite magnetic force #2 (the direction in which the magnetic field is applied), and the direction in which the normal portion of the composite magnetic force #2 moves (the direction in which the applied magnetic field moves) are all perpendicular to each other, as per Fleming's rule.

When the portion of the composite magnetic field #2 that penetrates the surface of the tubular conductor 110G (the portion with a normal component) rotates in the circumferential direction of the tubular conductor 110G, an electromotive force is generated in the axial direction of the tubular conductor 110G. The generated electromotive force acts to increase the signal current flowing through the tubular conductor 110G (is added to the signal current). This phenomenon can be said to be an amplification effect in which the AC signal is amplified by traveling through a waveguide to which the tubular conductor 110G is treated as a waveguide and a magnetic field that flows axially and a magnetic field that rotates circumferentially is applied.

When the part of the composite magnetic field #2 that penetrates the surface of the tubular conductor 110G rotates in the circumferential direction of the tubular conductor 110G to provide energy to the signal current, the energy of the magnetic field in the rotating direction is used. This magnetic field in the rotating direction is generated by the central electron beam. The price of providing energy to the signal current is that the speed of the electrons in the electron beam slows down. In other words, the signal current is amplified by receiving the kinetic energy of the electrons that form the electron beam.

When some of the electrons in an electron beam slow down, the slowed-down electrons gather together and create spots of different electron densities in the electron beam. In conventional gyrotrons and the like, the collection of some of the electrons in an electron beam is called a bunch.

In summary, according to the concept of the disclosed technology, the signal amplifier section of a gyrotron according to the prior art is based on the principle of amplifying a signal current by utilizing the energy of electrons in an electron beam flowing through the center. To obtain this electron beam, the gyrotron required a power supply to heat the filament of the electron gun that generates the electrons, a high-voltage power supply to accelerate the generated electrons, a magnetic field generating section 120G to narrow the flow of electrons into a beam, and a container that maintains a vacuum inside.

Conventional gyrotrons are unable to utilize all of the energy of the electrons in the electron beam. Electrons in the electron beam that do not contribute to the amplification of the signal current collide with the collector and lose their energy. Ideally, all of the energy of the electron beam would be utilized, but in reality, some of the electron energy is wasted, and it is difficult to say that the power supply efficiency as an amplifier is high.

The gyrotron according to the prior art includes a signal amplifier section (cavity section) that amplifies the signal current, a magnetron section that generates the signal current, a collector that discards excess energy, etc. The electron gun described above is included in the magnetron section. Since the technology disclosed here is a technology related to the amplification of the signal current, a description of the magnetron section and collector section, etc. will be omitted.

Embodiment 1.
The electromagnetic wave amplifier 100 according to the disclosed technology is based on a novel idea as described above, and there is no similar prior art. The disclosed technology is also different from solid-state electromagnetic wave amplifiers that replace vacuum tubes with semiconductors.
Fig. 4 is an explanatory diagram showing a schematic configuration and an operating principle of the electromagnetic wave amplifier 100 according to the first embodiment. Figs. 5 to 7 are explanatory diagrams showing modified examples of the configuration of the electromagnetic wave amplifier 100 according to the first embodiment. Fig. 5 is an explanatory diagram supplementing the configuration of the permanent magnet type electromagnetic wave amplifier 100. Fig. 6 is an explanatory diagram supplementing the configuration of the multiple magnet type electromagnetic wave amplifier 100. Fig. 7 is an explanatory diagram supplementing the configuration of the electromagnet type electromagnetic wave amplifier 100.

As shown in FIG. 5, the electromagnetic wave amplifier 100 according to the first embodiment includes a tubular conductor 110 for passing a signal current, a magnetic field generating unit 120 consisting of a permanent magnet arranged on the outer periphery of the tubular conductor 110, and a central conductor 130 arranged in the center of the tubular conductor 110.

The tubular conductor 110 is applied with an axial magnetic field by the magnetic field generating unit 120 arranged on the outer periphery. The central conductor 130 is connected to the amplification power supply 140 that supplies amplification power. The central conductor 130, energized by the amplification power supply 140, generates a rotational magnetic field that rotates around the axis of the tubular conductor 110. Filter coils 150 are connected in series to the input side end and the output side end of the central conductor 130. The filter coils 150 are provided for the purpose of preventing high-frequency AC current from leaking to the amplification power supply 140. As shown in FIG. 5, a signal current is introduced to the electromagnetic wave amplifier 100 through a signal introduction section 111 and an input terminal 112 provided on the tubular conductor 110. The magnetic field generating unit 120 may be configured by combining rod-shaped magnets. A wire for extracting an amplified signal is connected to the output side of the tubular conductor 110. An output terminal 115 has the same structure as the input terminal 112, and a line for extracting the amplified signal is also connected here.

The electromagnetic wave amplifier 100 according to the first embodiment is configured to pass a current through a central conductor 130 provided in the center, instead of the current for amplification that conventional gyrotrons pass as an electron beam (see FIG. 5). Because the electromagnetic wave amplifier 100 according to the first embodiment has this configuration, it does not require a filament, a power source for heating the filament, a high-voltage power source for accelerating electrons, or a mechanism for generating a strong magnetic field for constricting the electrons into a beam.
The configuration of providing a central conductor 130 in the center to pass current through was conceived from a different perspective of the "interaction between the electrons in the electron beam and the signal current" on which the conventional technology relies for its operation, and is a novel configuration that could not be conceived of from the conventional technology that assumes the existence of an electron beam in the center.

The central conductor 130 can easily pass a large current if a metal with low resistance, such as copper, is used. The electromagnetic wave amplifier 100 according to the disclosed technology uses an inexpensive low-voltage power supply instead of an expensive high-voltage power supply, thereby reducing costs. The behavior of the free electrons flowing through the central conductor 130 is the same as the behavior of electrons in the electron beam of a gyrotron according to the conventional technology, and acts to amplify the signal current in the same way as the conventional technology.

The electromagnetic wave amplifier 100 according to the disclosed technology does not require the use of a vacuum vessel with an output window, so that an electromagnetic wave amplifier 100 that amplifies a signal current can be realized with a simple structure. The electromagnetic wave amplifier 100 does not require power for heating a filament or power for applying a high voltage, so that power saving can also be achieved.

Just as the tubular conductor 110G and the electron beam are insulated by a vacuum space in the prior art gyrotron, the electromagnetic wave amplifier 100 also needs to insulate the tubular conductor 110 and the central conductor 130. The insulation between the tubular conductor 110 and the central conductor 130 may be achieved using an insulator or dielectric material containing gas. This insulation may be achieved by sealing air bubbles in an insulator, such as foamed resin. For this insulation, an insulating part such as a resin may be used as the member supporting the central conductor 130.

The clustering of electrons that occurs in the gyrotron according to the prior art also occurs in the central conductor 130 of the electromagnetic wave amplifier 100. The filter coil 150 provided in the electromagnetic wave amplifier 100 according to the first embodiment corresponds to this, and is provided to prevent the high-frequency current superimposed in the central conductor 130 from leaking to the amplification power supply 140. The filter coil 150 may be a through-type magnetic component such as a ferrite bead, as long as it does not leak high-frequency current. As will be explained in more detail later, in a configuration that amplifies a signal current of even higher frequency, leakage can be prevented by the magnetic properties of the connecting conductor itself, so that the filter coil 150 may not be provided.

When the electrons flowing through the central conductor 130 slow down, the voltage drop in the central conductor 130, which has a small resistance and is actually small, increases. The product of the increase in voltage drop in the central conductor 130 and the current passing through it corresponds to the power input to the central conductor 130. The power input to the central conductor 130 is used to amplify the signal current through the magnetic field as described above.

Figure 8 is an explanatory diagram showing a first configuration example in which a coaxial cable 160 is connected to the electromagnetic wave amplifier 100 according to the first embodiment. Figure 9 is an explanatory diagram showing a second configuration example in which a coaxial cable 160 is connected to the electromagnetic wave amplifier 100 according to the first embodiment.

The configuration example shown in Fig. 8 includes a coaxial cable 160 and a coaxial tube 170 consisting of an inner conductor 171 and an outer conductor 172. The right end of the outer conductor 172 in Fig. 8 is conical with a gradually increasing diameter so as to be connectable with the tubular conductor 110. This conical portion is called a connection portion 174. The right end of the inner conductor 171 in Fig. 8 is provided with an input terminal 112.
As shown in FIG. 8, the electromagnetic wave amplifier 100 according to the first embodiment may be configured such that a coaxial cable 160 carrying a high-frequency current is connected to an input terminal 112, and the inner conductor 171 of a coaxial tube 170 is shaped like a pipe, with a central conductor 130 disposed therein.

When using the coaxial cable 160 to guide the signal current to the electromagnetic wave amplifier 100, it is desirable to make the impedance of the part of the coaxial tube 170 to which the coaxial cable 160 is connected equal to the impedance of the coaxial cable 160. Therefore, the part of the coaxial tube 170 adopts a shape that makes the impedance equal. Since the impedance of a general-purpose coaxial cable is 75 [Ω] or 50 [Ω], a connector that adjusts the impedance may be used for the connection.

As shown in FIG. 8, the right end of the outer conductor 172 of the coaxial tube 170 is a cone-shaped connection 174, as described above, and the right end of the inner conductor 171 is provided with an input terminal 112 adjusted to a suitable length. Inside the connection 174, the state of the signal current flowing through the outer conductor 172 approaches the state of the current flowing through the waveguide as the diameter increases, and the signal current flowing through the inner conductor 171 gradually decreases as it progresses and eventually disappears. In other words, the state of the signal current traveling through the connection 174 transitions from the state in the coaxial tube 170 to the state in the waveguide. At the point where the signal current transitions to the state in the waveguide, the signal current flowing through the inner conductor 171 disappears, so the input terminal 112 is provided up to that point. Although it may be omitted in other figures, the input terminal 112 shown in other figures also has a length up to the same point.

The ratio of the inner diameter of the outer conductor 172 of the coaxial cable 160 or the coaxial tube 170 to the outer diameter of the inner conductor 171 can be uniquely calculated by setting an insulator or dielectric that separates the outer conductor 172 from the inner conductor 171. However, the diameter of the coaxial cable 160 or the coaxial tube 170 must not be too large. If the diameter is too large, the behavior of the waveguide is mixed when a high-frequency signal current is passed through, and the impedance is not suitable. For high-frequency applications, a coaxial cable 160 or a coaxial tube 170 with a small diameter is used. On the other hand, if the diameter is too small, the cross-sectional area of the conductor of the coaxial cable 160 or the coaxial tube 170 becomes small, and the loss increases especially when a large current is passed through it. In the electromagnetic wave amplifier 100 that amplifies a high-frequency signal current, a thin coaxial cable 160 may be used on the input side of a low power, and a waveguide with low loss may be used on the output side.

Figure 9 is an explanatory diagram showing a second example of a configuration in which a coaxial cable 160 is connected to the electromagnetic wave amplifier 100 according to the first embodiment. As shown in Figure 9, the electromagnetic wave amplifier 100 according to the first embodiment may be configured to share the inner conductor 171 of the coaxial tube 170, which passes a high-frequency AC signal current, with the central conductor 130, which passes a DC electromagnetic wave amplification current.

Since the inner conductor 171 and the central conductor 130 are combined, the electromagnetic wave amplifier 100 shown in Fig. 9 includes two types of filters. The first type of filter is a low-cut filter, which is provided at a portion where an AC signal current is input. The second type of filter is a high-cut filter, which is provided at a portion where a DC electromagnetic wave amplification current is input.
The low-cut filter may be realized by inserting in series a filter capacitor 155. The low-cut filter is not limited to the filter capacitor 155, and a transformer including an equivalent configuration may be used. The low-cut filter portion may be shaped to function as an antenna.
The high-cut filter may be realized by inserting a filter coil 150 in series. The high-cut filter is not limited to a coil made of wound conductor wire, and may use a through-type magnetic component such as a ferrite bead. Ferrite beads are effective when the frequency of the signal current is high.
The low-cut filter and the high-cut filter are not limited to the above configuration, but may be appropriately determined depending on the specifications of the electromagnetic wave amplifier 100 .

The electromagnetic wave amplifier 100 according to the first embodiment may have a number of possible modifications in configuration. Fig. 6 shows one of these modifications, and is an explanatory diagram supplementing the configuration of the electromagnetic wave amplifier 100 of a multiple magnet type. In the electromagnetic wave amplifier 100 shown in Fig. 6, the magnetic field generating unit 120 shown in Fig. 5 is realized by using multiple permanent magnets instead of one permanent magnet. Specifically, in the electromagnetic wave amplifier 100 shown in Fig. 6, the magnetic field generating unit 120 is configured by arranging the individual permanent magnets in series with their polarities facing each other. Of course, the magnetism of each permanent magnet may be aligned in the same direction.
Realizing the magnetic field generating unit 120 using a plurality of permanent magnets has the advantages of being able to use small magnets that are easily available, and being able to locally generate an arbitrarily strong magnetic field.

The electromagnetic wave amplifier 100 according to the first embodiment may be modified in a configuration different from that described above. FIG. 7 is an explanatory diagram supplementing the configuration of the electromagnetic wave amplifier 100 of the electromagnet type. The electromagnetic wave amplifier 100 shown in FIG. 7 is realized by using an electromagnet instead of a permanent magnet for the magnetic field generating unit 120 shown in FIG. 5.

There are several possible modifications of the electromagnetic wave amplifier 100 according to the first embodiment. Figures 10 to 12 are schematic diagrams showing modifications of the electromagnetic wave amplifier 100 according to the first embodiment. Figure 10 is a schematic diagram showing the basic configuration of the electromagnetic wave amplifier 100 according to the first embodiment. Figure 11 is a schematic diagram showing a first modification of the electromagnetic wave amplifier 100 according to the first embodiment. Figure 12 is a schematic diagram showing a second modification of the electromagnetic wave amplifier 100 according to the first embodiment.

The electromagnet-type electromagnetic wave amplifier 100 shown in Figures 10 to 12 has the effect of applying a magnetic field suitable for amplifying a signal current according to specifications by appropriately setting the current flowing through the electromagnet coil.

As shown in Figures 11 and 12, the electromagnet type electromagnetic wave amplifier 100 according to embodiment 1 can also be made to have a circular ring shape. Making the electromagnet type electromagnetic wave amplifier 100 into a circular ring shape has the advantage that the longitudinal size is small and easy to handle. The circular electromagnet shown in Figures 11 and 12 is composed of a toroidal coil. The use of a toroidal coil has the advantage of reducing leakage magnetic fields and mitigating the magnetic effects on the surrounding environment.

The electromagnet-type electromagnetic wave amplifier 100 shown in FIG. 12 includes, in addition to the configuration of FIG. 11, a magnetic member that magnetically connects the openings at both ends of the coil. This magnetic member is also called a magnetic yoke 230. The inclusion of the magnetic yoke 230 has the effect of further suppressing leakage of the magnetic field.

Figures 11 and 12 show that the electromagnet type electromagnetic wave amplifier 100 can be bent into a circular shape, but the multiple magnet type electromagnetic wave amplifier 100 shown in Figure 6 may also have the tubular conductor 110 bent as appropriate.

As described above, the electromagnetic wave amplifier 100 according to the first embodiment has the above configuration, and therefore does not use a vacuum vessel with an output window, an electron gun with a filament, a power supply for heating the filament, a strong magnet for focusing the electrons into a beam, or a high-voltage power supply for accelerating the electrons. In this way, the electromagnetic wave amplifier 100 according to the disclosed technology can realize an electromagnetic wave amplifier 100 with a simple configuration, and achieves the effect of achieving high efficiency and power saving by using a low-voltage amplification power supply 140.

Embodiment 2.
The electromagnetic wave amplifier 100 according to the second embodiment has the same configuration as that shown in the first embodiment, but is modified in the shape of the tubular conductor 110. Fig. 13 is an explanatory diagram showing a first configuration example of the electromagnetic wave amplifier 100 according to the second embodiment. Fig. 14 is an explanatory diagram showing a second configuration example of the electromagnetic wave amplifier 100 according to the second embodiment. The tubular conductor 110 according to the disclosed technology can be regarded as a waveguide.
The electromagnetic wave amplifier 100 according to the second embodiment uses the same reference numerals as those used in the first embodiment, and duplicated explanations will be omitted as appropriate.

The electromagnetic wave amplifier 100 shown in Fig. 13 includes a resonant cavity 180 in a part of a tubular conductor 110 that can be regarded as a waveguide. The resonant cavity 180 has a function of resonating a signal current at a desired frequency. The electromagnetic wave amplifier 100 including the resonant cavity 180 has an effect of passing signals of a design frequency and suppressing signals other than the design frequency. The configuration including the resonant cavity 180 corresponds to a klystron in terms of conventional technology.
The resonant cavity 180 can be realized, for example, by a groove-shaped recess extending in the circumferential direction provided on the inner wall of the tubular conductor 110. The length of the path through which the signal current flows on the inner wall surface of the resonant cavity 180 is designed to be an integer multiple of the wavelength of the signal current. By designing the path length in this manner, the phase of the signal current passing through the inlet of the resonant cavity 180 is aligned with the phase of the signal current passing through the outlet of the resonant cavity 180 around the inner wall of the resonant cavity 180, causing resonance.

As described above, electromagnetic wave amplifier 100 shown in FIG. 13 has the effects shown in the first embodiment, as well as a bandpass filter characteristic that passes the design frequency.
Furthermore, since the electromagnetic wave amplifier 100 shown in FIG. 13 has the above-mentioned filter characteristics, if a portion of the output is returned to the input, it is possible to realize an oscillator that emits an electromagnetic wave having a specific frequency, like a magnetron.

The electromagnetic wave amplifier 100 shown in Fig. 14 includes a slow wave circuit 190 in a portion of a tubular conductor 110 that can be considered as a waveguide. The slow wave circuit 190 has the function of increasing the time during which the signal current is amplified by extending the effective path. The electromagnetic wave amplifier 100 including the slow wave circuit 190 is characterized by a large amplification of the signal current. The configuration including the slow wave circuit 190 corresponds to a traveling wave tube in the prior art. In addition, because the path through which the signal current passes is meandering, this traveling wave tube is expressed as being meander-shaped, being of a meander type, or having a meander shape.
The slow wave circuit 190 can be realized, for example, by providing a pleated protrusion extending in the circumferential direction on the inner wall of the tubular conductor 110. By providing the slow wave circuit 190, the path through which the signal current flows becomes longer, and the apparent traveling speed of the signal current in the axial direction becomes slower.

As described above, the electromagnetic wave amplifier 100 shown in FIG. 14 has the effect of being able to increase the amount of amplification of the signal current compared to the configuration of embodiment 1 having the same length of tubular conductor 110. From another perspective, the electromagnetic wave amplifier 100 shown in FIG. 14 has the effect of being able to shorten the tubular conductor 110 compared to the configuration of embodiment 1 having the same amplification capacity.

The configurations shown in the second embodiment are examples that embody the technology disclosed herein, and are not intended to be limiting. Needless to say, they can be freely combined with the modifications shown in the first embodiment.

Embodiment 3.
The second embodiment shows a modified form of the tubular conductor 110 that can be regarded as a waveguide for the electromagnetic wave amplifier 100 according to the disclosed technology. In particular, Fig. 14 relating to the second embodiment shows a configuration including a slow wave circuit 190, which corresponds to a traveling wave tube in the prior art.
The electromagnetic wave amplifier 100 according to the third embodiment has the same configuration as that shown in the first embodiment, but is modified between the input terminal 112 and the output terminal 115. The electromagnetic wave amplifier 100 according to the third embodiment uses the same reference numerals as those used in the first and second embodiments. Also, duplicated explanations will be omitted as appropriate.

Figure 15 is an explanatory diagram showing a configuration example of an electromagnetic wave amplifier 100 according to embodiment 3. The electromagnetic wave amplifier 100 shown in Figure 15 includes a coiled slow-wave circuit 195 formed of a conductor between the input terminal 112 and the output terminal 115. The configuration including the coiled slow-wave circuit 195 corresponds to a helix-type traveling wave tube in the prior art.

The electromagnetic wave amplifier 100 shown in FIG. 15 includes a coiled slow-wave circuit 195, and the inductance of the coiled slow-wave circuit 195 prevents the flow of signal current, which is an alternating current above a certain frequency. As a result, the signal current does not flow through the coiled slow-wave circuit 195 inside the tubular conductor 110, but only through the tubular conductor 110.

In the electromagnetic wave amplifier 100 according to the third embodiment having the above configuration, the signal current flows only through the tubular conductor 110, and it can be regarded as a waveguide through which the signal current flows. By providing the coiled slow-wave circuit 195, even if the tubular conductor 110 is made thin, the behavior of the signal current flowing therein is equivalent to the behavior of the signal current flowing through a waveguide, so that the diameter of the tubular conductor 110 can be reduced, and the electromagnetic wave amplifier 100 can be made smaller.

Figure 16 is an explanatory diagram showing a configuration example in which a coaxial cable 160 is connected to an electromagnetic wave amplifier 100 according to embodiment 3. Figure 16 shows that the length of the connection part 174 shown in Figures 8 and 9 can be shortened by using a coiled slow wave circuit 195.

As described above, the electromagnetic wave amplifier 100 according to the third embodiment has the above-mentioned configuration, and therefore, in addition to the effects shown in the first embodiment, it has the effect of being able to miniaturize the electromagnetic wave amplifier 100.

The configurations shown in embodiment 3 are all examples that embody the disclosed technology, and are not intended to be limiting. Needless to say, they can be freely combined with the respective modifications shown in embodiment 1 and embodiment 2.

Embodiment 4.
The electromagnetic wave amplifier 100 according to the fourth embodiment has the same configuration as that shown in the first embodiment, but is miniaturized as a whole. FIG. 17 is an explanatory diagram showing a configuration example of the electromagnetic wave amplifier 100 having a microstructure according to the fourth embodiment. FIG. 18 is a configuration diagram showing the configuration of an amplification waveguide 200 according to the fourth embodiment. FIG. 19 is a configuration diagram showing a modified example of the amplification waveguide 200 according to the fourth embodiment. FIG. 20 is a schematic diagram of the electromagnetic wave amplifier 100 using a plurality of amplification waveguides 200 having a microstructure. FIG. 21 is an explanatory diagram showing an example of a method of connecting a plurality of amplification waveguides 200 having a microstructure.
Except where a different name is intentionally given, the electromagnetic wave amplifier 100 according to the fourth embodiment uses the same reference numerals as those used in the first to third embodiments, and duplicated explanations will be omitted as appropriate.

As shown in FIG. 17, the electromagnetic wave amplifier 100 according to the fourth embodiment includes an input side reflector 210 and an output side reflector 212 for reflecting the signal current, an amplification waveguide 200, and a magnetic yoke 230.

As shown in FIG. 18, the amplification waveguide 200 according to the fourth embodiment includes, from the inside, a central conductor 130, an insulator section 240, and a tubular conductor 110. The thin cylindrical component consisting of these three components is collectively called the amplification waveguide 200. The insulator section 240 may be a dielectric. Furthermore, the insulator section 240 may function as an insulator or a dielectric, regardless of the phase of gas, liquid, or solid. The tubular conductor 110 according to the fourth embodiment may be realized by forming a metal coating such as silver plating on the outside of the insulator section 240. Furthermore, the tubular conductor 110 does not need to be solid, and may be a conductive liquid such as an electrolyte. In other words, the tubular conductor 110 may be realized as a conductor tube with the liquid side interface when the insulator section 240 is immersed in a conductive liquid.

The amplification waveguide 200 can handle infrared rays, a type of electromagnetic wave with a wavelength of 30 μm, by having a diameter of, for example, about 30 μm. For the insulator section 240, a material must be selected that has low dielectric loss in the frequency range to be used and that passes electromagnetic waves in that frequency range. When handling infrared rays, the insulator section 240 may be made of a material such as resin or glass. When the electromagnetic waves to be handled are visible light, it is recommended that the insulator section 240 be made of a transparent material.

As shown in Figure 19, the amplification waveguide 200 according to the fourth embodiment may be configured with a microfabricated groove and a lid that covers the groove, and may have a prismatic shape. It is desirable that the cross section of the central conductor 130 shown in Figure 19 has the same width and height as much as possible, so as to approximate the characteristics of a cylindrical waveguide.

The electromagnetic wave amplifier 100 according to embodiment 4 is mentioned because it handles a signal current of a higher frequency than those in the configurations according to embodiments 1 to 3. The filter coil 150 shown in embodiments 1 to 3 may have a small inductance when handling a high-frequency signal current. In particular, if the frequency of the signal current being handled approaches the frequency of light, the AC current of that frequency can be suppressed only by the inductance of the conductor itself for passing the amplification power supply current. That is, in the configuration of embodiment 4, the filter coil 150 as an independent component can be omitted.

The portion where the conductor for passing the amplification power supply current penetrates into the tubular conductor 110 corresponds to the input terminal 112 shown in the first to third embodiments. The amplification power supply side of this portion acts as an antenna for receiving electromagnetic waves, and superimposes a signal current on the amplification current as shown in FIG. 9. The central conductor 130 inside the tubular conductor 110 behaves as if it were the coiled slow wave circuit 195 shown in FIG. 15, and no signal current flows through the central conductor 130 inside the tubular conductor 110.

Fig. 20 is a schematic diagram of an electromagnetic wave amplifier 100 that uses a plurality of microstructure amplification waveguides 200. That is, Fig. 20 shows the use of a plurality of amplification waveguides 200, each of which is considered as a single unit. In Fig. 20, the amplification power supply 140 and the power supply conductors connected to the individual tubular conductors 110 shown in Fig. 17 are omitted.
Fig. 21 is an explanatory diagram illustrating a method of connecting a plurality of amplification waveguides 200 having a microstructure. As shown in Fig. 21, the method of connecting the amplification waveguides 200 may be parallel, series, or a combination of parallel and series. As described above, the signal current flows only in the inner surface portion of the amplification waveguide 200 and does not flow to the outside, so that when arranging the amplification waveguides 200, it does not matter if the outsides of adjacent amplification waveguides 200 come into contact with each other.

The electromagnetic wave amplifier 100 according to the disclosed technology may be configured by bundling a plurality of tubular conductors 110 together and providing an electromagnetic magnetic field generating unit 120 on the outside thereof, as shown in FIG. 7.

As described above, the electromagnetic wave amplifier 100 according to the fourth embodiment has a miniaturized tubular conductor 110, and therefore can amplify a high-frequency signal current in comparison with the configurations shown in the first to third embodiments. The high-frequency signals input to the electromagnetic wave amplifier 100 according to the fourth embodiment include those output by a magnetron (radio waves) and those output by an LED (light).

As described above, the electromagnetic wave amplifier 100 according to embodiment 4 can output a large electromagnetic wave by using multiple amplification waveguides 200 as a unit.

Within the scope of the present invention, any combination of the embodiments, any modification of any component of each embodiment, or any omission of any component of each embodiment are possible.

The electromagnetic wave amplifier 100 according to the disclosed technology can be applied to electromagnetic wave amplifiers in various radar devices and electromagnetic wave amplifiers in various communication devices, and has industrial applicability.

100 Electromagnetic wave amplifier, 110 Tubular conductor, 111 Signal introduction section, 112 Input terminal, 115 Output terminal, 120 Magnetic field generating section, 130 Central conductor, 140 Amplification power supply, 150 Filter coil, 155 Filter capacitor, 160 Coaxial cable, 170 Coaxial tube, 171 Inner conductor, 172 Outer conductor, 174 Connection section, 180 Resonant cavity section, 190 Slow wave circuit, 195 Coil-shaped slow wave circuit, 200 Amplification waveguide, 210 Input side reflector, 212 Output side reflector, 230 Magnetic yoke, 240 Insulator section.

Claims (12)

The magnetic field generating unit includes a central conductor, a tubular conductor, and a magnetic field generating unit, in that order from the inside.
the central conductor has an axial shape, is disposed at the center of the tubular conductor, and passes a current in the longitudinal direction of the axis of the tubular conductor;
A magnetic field is applied to the tubular conductor in the longitudinal direction of the axis by the magnetic field generating unit disposed on the outer periphery of the tubular conductor,
A first resultant magnetic field is generated around the outside of the tubular conductor, the first resultant magnetic field rotating in a spiral shape.
An AC signal current whose polarity alternates sequentially travels through the first resultant magnetic field through the tubular conductor ;
A signal magnetic field that alternates in the direction of rotation generated by the signal current travels through the first composite magnetic field,
the first resultant magnetic field and the signal magnetic field are combined to generate a second resultant magnetic field;
The second resultant magnetic field generates an electromotive force in the longitudinal direction of the axis of the tubular conductor, and acts to increase the signal current.
Electromagnetic wave amplifier. The electromagnetic wave amplifier according to claim 1, further comprising an insulating portion disposed between the tubular conductor and the central conductor, which is not a semiconductor and functions as an insulator or dielectric regardless of the phase of gas, liquid, or solid. The electromagnetic wave amplifier according to claim 1, wherein the magnetic field generating unit is a combination of multiple permanent magnets. The electromagnetic wave amplifier according to claim 1, wherein the inner wall of the tubular conductor has a groove-shaped recess or a pleated protrusion extending in the circumferential direction of the tubular conductor. The electromagnetic wave amplifier of claim 1 further comprising a high-cut filter connected in series to the central conductor. 2. The electromagnetic wave amplifier according to claim 1, further comprising an input terminal disposed inside the tubular conductor at a position that pairs with a connection portion that introduces the signal current flowing through the tubular conductor. The electromagnetic wave amplifier according to claim 6, further comprising a coiled slow wave circuit disposed inside the tubular conductor and connected to the input terminal. The electromagnetic wave amplifier according to claim 6, wherein the central conductor also functions as the input terminal. The electromagnetic wave amplifier according to claim 1, wherein the tubular conductor is curved or bent. The electromagnetic wave amplifier according to claim 2, wherein the tubular conductor is a conductive member formed on the surface of the insulating body. The electromagnetic wave amplifier according to claim 2, in which a plurality of amplification waveguides each consisting of the central conductor, the insulating portion, and the tubular conductor are arranged side by side. A radar device equipped with the electromagnetic wave amplifier according to claim 1.

Images