JP6341839B2 - Antenna device - Google Patents

Description

  The present invention relates to an antenna device that reduces interference with radio waves when not in use.

  In general, even when a metal antenna is not used, it interferes with radio waves existing in the vicinity, and scatters radio waves. For this reason, when a plurality of antennas are arranged in a region shorter than the wavelength of the radio wave to be used, the antenna characteristics deteriorate due to interference between adjacent antennas. For this reason, it is desirable that the antenna has little interference with radio waves when not used.

  Therefore, conventionally, an antenna device has been proposed that reduces interference with radio waves when not in use by not making the antenna of metal and making the antenna when not in use electrically transparent (for example, Patent Document 1). reference). The conventional antenna device disclosed in Patent Document 1 has a pair of electrode terminals close to the ground plane, and there is a dielectric tube containing an ionizing gas between the electrode terminals. Supply power from. As a result, the ionizing gas in a plasma state acts as a conductor against high frequencies. In this state, the dielectric tube operates as an antenna by flowing a high-frequency current from a high-frequency power source to the pair of electrode terminals. With this configuration, the dielectric tube becomes a mere dielectric when not in use, and therefore does not become a large interference source even when the antenna is arranged close to the periphery.

JP 2010-148025 A

  In general, since an antenna uses a resonance phenomenon of radio waves (high frequency), the antenna length depends on the wavelength of the radio waves. In the conventional antenna device, since the entire dielectric tube is used as an antenna, the electrode terminals provided at both ends of the dielectric tube also constitute a part of the antenna.

  Therefore, in the above antenna device, in order to realize an antenna operation in a high frequency band (for example, a GHz band), it is necessary to make the electrode terminal fine. On the other hand, there is an upper limit to the current value that can be stably passed per unit surface area of the electrode terminal. For this reason, when a large amount of power is supplied to the fine electrode terminal, the life is reduced due to an increase in current density, and in the worst case, the dielectric tube is broken.

  In order to operate plasma as an antenna, a certain amount of discharge current needs to flow through the plasma. Therefore, when a small electric power is supplied to the electrode terminal, the conductivity as a plasma conductor deteriorates. For this reason, there has been a problem that the amount of radio waves radiated from the high frequency power supply through the dielectric tube is extremely small.

  The present invention has been made to solve the above-described problems, can reduce interference with radio waves when not in use, and does not require a size change of the electrode terminal for plasma excitation according to the wavelength. Therefore, an object of the present invention is to provide an antenna device capable of realizing an antenna operation in a high frequency band.

A ground conductor, a dielectric tube having an ionizing gas therein, a folded portion, and the folded portion and both ends of the dielectric tube penetrating the ground conductor so that the both ends are disposed on the ground conductor, and both ends of the dielectric tube An electrode terminal provided on the electrode terminal, a plasma excitation power source that is connected to the electrode terminal to bring the ionizing gas into a plasma state, and metal pins inserted into the dielectric tube at both ends of the dielectric tube from the ground conductor, A high-frequency power source that supplies high-frequency power to the metal pin, a filter that cuts off the low-frequency band, a feed line that connects the metal pin and the high-frequency power source at a high frequency via the filter , a metal pin that covers the ground pin, A grounded metal box and a dielectric tube are enclosed, grounded to the bottom surface of the metal box, and provided with metal cylinders whose upper ends are positioned on both ends of the dielectric tube from the metal pins .

  According to the present invention, since it is configured as described above, it is possible to reduce interference with radio waves when not in use, and it is not necessary to change the size of the electrode terminal for plasma excitation according to the wavelength. Antenna operation in the band can be realized.

It is a perspective view which shows the structure of the antenna device which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the structure of the antenna device which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the whole feed line containing the filter in Embodiment 1 of this invention, (a) It is a top view, (b) It is a bottom view. It is a figure which shows the structure of the filter in Embodiment 1 of this invention, (a) is a top view, (b) is a bottom view. It is a perspective view which shows the structure of the antenna apparatus which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the structure of the antenna apparatus which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the structure of the antenna apparatus which concerns on Embodiment 3 of this invention. It is sectional drawing which shows the structure of the antenna apparatus which concerns on Embodiment 4 of this invention. It is sectional drawing which shows the structure of the antenna device which concerns on Embodiment 5 of this invention. It is sectional drawing which shows the structure of the antenna device which concerns on Embodiment 6 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a perspective view showing a configuration of an antenna device according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view.
The antenna device according to Embodiment 1 is provided with a ground conductor 1 having a hole 101 as shown in FIGS. And the dielectric tube 2 contained so that the ionizing gas may not leak into the inside of the hole 101 of the ground conductor 1 penetrates. The dielectric tube 2 has a folded portion 201 that is folded at least at one place. The folded portion 201 and both ends of the dielectric tube 2 penetrate through the hole 101 of the ground conductor 1 so as to be arranged vertically with the ground conductor 1 as a boundary. In the example of FIGS. 1 and 2, the dielectric tube 2 is configured in a U shape (monopole antenna shape), the folded portion 201 is disposed vertically above the ground conductor 1, and both ends are perpendicular to the ground conductor 1. It is arranged on the lower side.

  Further, an inert gas containing a rare gas as a main component is used as the ionizing gas sealed in the dielectric tube 2. The rare gas may contain at least one of helium (He), neon (Ne), argon (Ar), xenon (Xe), and krypton (Kr). Further, in order to improve discharge efficiency, mercury (Hg) may be enclosed together with a rare gas. The pressure of the ionizing gas may be in a pressure range that can maintain a stable glow-like discharge, and the pressure of the ionizing gas can be 10 Pa to 15 kPa. In particular, for use as a plasma antenna in the microwave and millimeter wave bands (300 MHz to 300 GHz), it is preferably in the range of 100 Pa to 7 kPa where a high electron density can be obtained.

  In addition, as the member of the dielectric tube 2, for example, a material having electrical insulating properties such as a ceramic material such as quartz, borosilicate glass or alumina, a composite material such as a carbon reinforced plastic, or a combination thereof is used.

  A pair of electrode terminals 3 and 4 are provided at both ends of the dielectric tube 2. The electrode terminals 3 and 4 are connected to the discharge electrodes 301 and 401 provided at both ends of the dielectric tube 2, one end is connected to the bottom of the discharge electrodes 301 and 401, and the other end is led out of the dielectric tube 2. Lead wires 302 and 402.

  As a member of the discharge electrodes 301 and 401, for example, a material applied to the cathode of the discharge tube such as nickel (Ni) or tungsten (W) can be applied. The shape of the discharge electrodes 301 and 401 is the shape of a cylinder, cylinder, bottomed opening (cup), spiral, coil, filament, etc. produced by a known method such as plate bending, injection molding, member welding or caulking. Can be used. Moreover, by making the discharge electrodes 301 and 401 have a structure having a gap of 1 to 5 mm, the discharge efficiency can be improved by utilizing the hollow cathode effect. In addition, the discharge efficiency can be improved by applying an electron-emitting substance (not shown) to the surfaces of the discharge electrodes 301 and 401.

  The surface area of the discharge electrodes 301 and 401 is set such that the discharge current per unit area and unit gas pressure satisfies the stable discharge conditions of the discharge electrodes 301 and 401. For example, when the discharge electrodes 301 and 401 are used as cold cathodes, the surface area may be such that the discharge current per unit area and unit gas pressure is 1E-7 to 1E-5 mA / cm 2 · Pa 2. By setting the surface area to be large, plasma can be stably generated. Although it is possible to discharge with a surface area smaller than this, the life of the discharge electrodes 301 and 401 is shortened because the discharge electrodes 301 and 401 are damaged by sputtering of the electrode surface and thermalization (arc) of the plasma. .

  The members of the lead wires 302 and 402 are made of a conductive material whose thermal expansion coefficient approximates that of the material constituting the dielectric tube 2 in order to ensure the airtightness of the end portion of the dielectric tube 2. The For example, when the dielectric tube 2 is made of hard glass, molybdenum (Mo), tungsten (W), or the like can be used. 1 and 2, only one lead wire 302, 402 is shown at each end of the dielectric tube 2. However, when the discharge electrodes 301, 401 are used as a hot cathode, a plurality of lead wires 302, 402 are shown. Lead wires 302, 402 can be provided.

  Note that both ends of the dielectric tube 2 are configured to have a size capable of accommodating the discharge electrodes 301 and 401 inside the dielectric tube 2. Here, the inner diameters at both ends of the dielectric tube 2 are only required to accommodate the discharge electrodes 301 and 401, and the inner diameters at the respective ends may be different. When plasma is generated by DC power, the durability of the dielectric tube 2 can be improved by increasing the dimensions of the discharge electrodes 301 and 401 on the cathode side and the inner diameter of the dielectric tube 2.

  Further, a plasma excitation power source 5 for bringing the ionizing gas contained in the dielectric tube 2 into a plasma state is connected to the lead wires 302 and 402 via a pair of wires. Then, low frequency power for exciting plasma is supplied from the plasma excitation power source 5. As a frequency of the low frequency power, a frequency from a direct current to a frequency of a radio wave (high frequency signal) can be used. The low frequency power may be intermittently supplied at a frequency higher than the frequency of the low frequency power. By supplying low frequency power intermittently, the low frequency power required for plasma maintenance can be reduced.

In addition, metal pins 6 and 7 are inserted into the dielectric tube 2 perpendicularly (including a substantially vertical meaning) to the dielectric tube 2 at both ends of the dielectric tube 2 relative to the ground conductor 1. ing. Note that the distances from the lower surface of the ground conductor 1 to the metal pins 6 and 7 are equal to each other, and are set to a short distance with respect to the wavelength of the high frequency used. The lengths of the metal pins 6 and 7 are shorter than the wavelength of the high frequency used.
Furthermore, the length from the position where the metal pins 6 and 7 are inserted into the dielectric tube 2 to the upper end (folded portion 201) of the dielectric tube 2 protruding above the ground conductor 1 is the wavelength of the high frequency used. The length is about 1/4.

  Further, a high frequency power supply 8 is connected to the metal pins 6 and 7 through a feed line 9 at a high frequency. The high frequency power supply 8 supplies high frequency power to the metal pins 6 and 7. As shown in FIG. 3, the feed line 9 includes coplanar lines (first and second lines) 903 and 904 that are formed on both surfaces of a dielectric substrate 901 and have a ground pattern 902 on a coplanar surface. The line 903 is configured on one surface (the lower surface in FIG. 3) of the dielectric substrate 901 and is a line connected to the high frequency power supply 8 side. The line 904 is configured on the other surface (the upper surface in FIG. 3) of the dielectric substrate 901 and is a line connected to the dielectric tube 2 side. Then, as shown in FIG. 4, the filter 905 shown in FIGS. 1 and 2 is configured by overlapping the line 903 and the line 904 with respect to the high frequency in-tube wavelength with the dielectric substrate 901 interposed therebetween. ing. This filter 905 is a resonance type band-pass filter that cuts off a low frequency band, and the length of about 1/4 of the high-frequency tube wavelength used is the main operating frequency.

Next, the operation principle of the antenna device according to Embodiment 1 shown in FIGS.
First, the case where the plasma excitation power source 5 is ON will be described. Here, a space above the ground conductor 1 is defined as a radiation area, and a space below the ground conductor 1 is defined as a radiation area outside.

  When the plasma excitation power source 5 is ON, power (low frequency power) for exciting the plasma from the plasma excitation power source 5 is supplied to the discharge electrodes 301 and 401 via the lead wires 302 and 402. And the ionizing gas in the dielectric tube 2 becomes a plasma state, and the dielectric tube 2 becomes a conductor in terms of high frequency. This is called a plasma conductor.

  On the other hand, the high frequency power from the high frequency power source 8 is divided into two by the feed line 9. Then, the high frequency power is supplied from the metal pins 6 and 7 to the plasma of the dielectric tube 2 serving as a plasma conductor via the filter 905.

  Here, the filter 905 is a resonance type band-pass filter, and operates at a length of about ¼ of the high-frequency tube wavelength to be used. It can be considered. Naturally, it is open in terms of low frequency, and the power (having a frequency component of about 20 kHz) supplied from the plasma excitation power supply 5 is cut off.

  For example, when the plasma excitation power supply 5 is turned on without providing the filter 905, a high voltage from the plasma excitation power supply 5 is applied to the high frequency power supply 8, and thus the high frequency power supply 8 may break down. In other words, the filter 905 serves to prevent a high voltage from the plasma excitation power source 5 from being applied to the high frequency power source 8.

  Further, when the filter 905 is not provided, a path that is short-circuited is formed in the middle of the dielectric tube 2 where plasma is generated, and plasma cannot be stably generated, so that it does not behave as a conductor at high frequency. Therefore, it is difficult to realize an antenna operation using a plasma conductor without using the filter 905.

  Returning to the explanation of the operation of the antenna device, the high-frequency power supplied to the plasma propagates to the upper side and the lower side of the dielectric tube 2, respectively. Here, since the high-frequency currents flowing through the two dielectric tubes 2 arranged in parallel have the same phase, they can be regarded as one plasma conductor. Therefore, the high-frequency current flowing through the plasma conductor propagates through the dielectric tube 2 while radiating radio waves. The dielectric tube 2 extending above the metal pins 6 and 7 operates as a folded monopole antenna above the ground conductor 1 and gives a directivity pattern of the monopole antenna to the radiation region.

Next, the case where the plasma excitation power supply 5 is OFF will be described.
When the plasma excitation power source 5 is OFF, the dielectric tube 2 behaves as a dielectric instead of a conductor. For this reason, most of the high-frequency power supplied via the feeder line 9 is reflected at the tips of the metal pins 6 and 7, and the antenna cannot be matched. Therefore, the amount of radio wave radiation in the radiation region is extremely small.

  In the above description, the monopole antenna-shaped dielectric tube 2 is shown. However, the dielectric tube 2 may have any shape that is bent so that both ends are located below the ground conductor 1. For this reason, for example, a loop structure, a helical structure, a folded structure, or the like can be used as an arbitrary structure suitable for the operation as an antenna. In addition, the tube diameter of the dielectric tube 2 can be changed like a conical antenna or a taper antenna in order to have a wideband frequency characteristic.

  In the above description, the periphery of the dielectric tube 2 is not illustrated, but the periphery of the dielectric tube 2 may be surrounded by an electrically insulating material. Here, as the electrically insulating material, a high vacuum of 0.1 mPa or less or a rare gas of 1 atm or more, an inert gas such as air or SF6, a ceramic such as quartz, borosilicate glass or alumina, or a plastic such as acrylic resin In addition, a material having electrical insulating properties such as a composite material such as carbon reinforced plastic, or a combination of these materials is used. In order to reduce the interference with the adjacent antenna when not in use, it is preferable to use an inert gas having a relative dielectric constant close to that of vacuum, a fluororesin or a carbon reinforced plastic having a low relative dielectric constant, or the like. In addition, by using a plastic or a composite material, resistance to external impact can be improved.

  As described above, according to the first embodiment, the plasma excitation electrode terminals 3 and 4 are separated from the high frequency power supply electrode terminals (metal pins 6 and 7), and the metal pins 6 and 7 are separated from each other. Since the filter 905 that cuts off the low frequency band is provided in the feed line 9 that connects the high frequency power supply 8 at a high frequency, it is possible to reduce interference with radio waves when not in use, and for plasma excitation in accordance with the wavelength. It is not necessary to change the size of the electrode terminals 3 and 4, and an antenna operation in a high frequency band (for example, a microwave band) can be realized.

  That is, in the present invention, when the plasma excitation power source 5 is ON, it operates as an antenna, and when the plasma excitation power source 5 is OFF, it behaves as being electrically transparent in the radiation region. Therefore, it does not become an interference source of adjacent antennas.

  Further, in the prior art, as the frequency increases, the electrode terminal for plasma excitation becomes finer, and considering the durability, only a small discharge power can be supplied to excite the plasma. For this reason, the loss of the plasma conductor is increased, and the amount of radiation from the plasma conductor in the radiation region is reduced. On the other hand, in the present invention, since the size of the electrode terminals 3 and 4 for plasma excitation can be made constant regardless of the frequency, a high discharge power can be supplied to excite plasma. Therefore, the loss of the plasma conductor is small, and the operation as an antenna is possible without causing a decrease in the amount of radiation in the radiation region.

  In addition, by providing the filter 905 in the high-frequency power supply line 9, it is possible to prevent the application of a high voltage to the high-frequency power source 8 and to stably maintain the plasma state.

Embodiment 2. FIG.
In the second embodiment, an antenna device capable of increasing the radiation amount in the radiation region as compared with the first embodiment will be described.
FIG. 5 is a perspective view showing a configuration of an antenna device according to Embodiment 2 of the present invention, and FIG. 6 is a cross-sectional view. The antenna device according to the second embodiment shown in FIGS. 5 and 6 is obtained by adding a metal box 10 to the antenna device according to the first embodiment shown in FIGS. Other basic configurations are the same, and only the different parts will be described with the same reference numerals.

  In the antenna device according to Embodiment 2, as shown in FIGS. 5 and 6, a metal box 10 that covers the metal pins 6 and 7 is provided. The metal box 10 is a box-shaped member having an upper surface opened, and the upper end is grounded to the lower surface (lower surface) of the ground conductor 1. That is, the metal box 10 and the ground conductor 1 are electrically connected and held at the ground potential of the high frequency power. As a connection method between the metal box 10 and the ground conductor 1, for example, a general connection method such as soldering, welding, or contact by screwing can be used. The member of the metal box 10 may be a low resistance to high frequency power, and materials such as copper (Cu) and aluminum (Al) can be applied. In addition, holes 1001 through which both ends of the dielectric tube 2 pass are provided on the bottom surface of the metal box 10. Further, a notch groove (or hole) 1002 through which the feeder line 9 passes is provided on the side surface of the metal box 10. Note that the sizes of the hole 1001 and the notch groove 1002 are as small as possible.

  Next, the operation principle of the antenna device according to Embodiment 2 shown in FIGS. Here, the operation when the plasma excitation power source 5 is OFF is the same as the configuration of the first embodiment, and only the case where the plasma excitation power source 5 is ON will be described below.

  In the antenna device shown in the first embodiment, the metal pins 6 and 7 are connected to the dielectric tube 2, and the current flowing from both ends of the dielectric tube 2 to the both ends (lower side) of the dielectric tube 2 is a radio wave outside the radiation region. Radiate. Therefore, this radiation deteriorates the radiation efficiency in the radiation region. Therefore, in the second embodiment, the metal box 10 is provided in order to improve the radiation efficiency deterioration.

  The radio wave radiated from the dielectric tube 2 or the metal pins 6 and 7 in the metal box 10 is retained inside by the metal box 10 and leaks and radiates from the hole 101 of the ground conductor 1 provided to pass the dielectric tube 2. Radiated to the area. In addition, this radio wave excites the plasma conductor and increases the amount of radiation from the plasma conductor.

  As described above, according to the second embodiment, since the metal box 10 that covers the metal pins 6 and 7 and is grounded to the ground conductor 1 is provided, the amount of radiation in the radiation region is different from that of the first embodiment. It becomes possible to increase more.

Embodiment 3 FIG.
In the third embodiment, an antenna device capable of increasing the radiation amount in the radiation region as compared with the second embodiment will be described.
FIG. 7 is a sectional view showing a configuration of an antenna apparatus according to Embodiment 3 of the present invention. The antenna device according to Embodiment 3 shown in FIG. 7 is obtained by adding a metal tube 11 to the antenna device according to Embodiment 2 shown in FIGS. Other basic configurations are the same, and only the different parts will be described with the same reference numerals.

  In the antenna device according to the third embodiment, as shown in FIG. 7, a metal cylinder 11 surrounding the dielectric tube 2 is provided in the metal box 10. The bottom surface of the metal cylinder 11 is grounded to the bottom surface in the metal box 10. That is, the metal cylinder 11 and the metal box 10 are electrically connected and held at the ground potential of the high frequency power. As a connection method between the metal cylinder 11 and the metal box 10, for example, a general connection method such as soldering, welding, fitting, screwing, or the like can be used. As a member of the metal cylinder 11, what is necessary is just low resistance with respect to high frequency electric power, and materials, such as copper (Cu) and aluminum (Al), can be applied. Further, the metal box 10 and the metal cylinder 11 can be integrally formed by machining or the like. Further, the upper end of the metal tube 11 is located on both ends (lower side) of the dielectric tube 2 with respect to the metal pins 6 and 7. The height of the metal cylinder 11 is configured to be shorter than about ¼ of the wavelength of the high frequency.

  Next, the operation principle of the antenna device according to Embodiment 3 shown in FIG. 7 will be described. Here, the operation when the plasma excitation power source 5 is OFF is the same as the configuration of the first embodiment, and only the case where the plasma excitation power source 5 is ON will be described below.

  In the antenna device according to the third embodiment, a part of the radio waves radiated from the metal pins 6 and 7 or the dielectric tube 2 accumulates in the metal box 10 and propagates downward through the inside of the metal tube 11 to radiate. Radiates out of the area. At this time, since the transmission path is between the dielectric tube 2 and the metal cylinder 11, when the height of the metal cylinder 11 is set to about 1/4 of the wavelength of the high frequency, the lower end of the metal cylinder 11 (metal box) The transmission line is cut off at the hole 1001) provided at 10 so that it is released and the upper end is short-circuited. Therefore, in terms of high frequency, it can be considered that there is a short-circuit wall at the upper end of the metal cylinder 11, and the amount of radio waves in the metal box 10 propagating through the metal cylinder 11 and radiating out of the radiation region is reduced. By reducing the amount of radiation outside the radiation region, radio waves leaking from the hole 101 provided in the ground conductor 1 increase, or electromagnetic waves (wave sources) that excite the plasma conductor increase. Therefore, the amount of radiation in the radiation region also increases.

  As described above, according to the third embodiment, the dielectric tube 2 is surrounded in the metal box 10, is grounded to the bottom surface in the metal box 10, and the upper end is connected to the dielectric tube 2 from the metal pins 6 and 7. Since the metal cylinders 11 located on both end sides of the first and second ends are provided, the amount of radiation in the radiation region can be further increased compared to the second embodiment.

  FIG. 7 shows the case where the lower end of the metal cylinder 11 is grounded to the bottom surface of the metal box 10 and the height of the metal cylinder 11 is given to the upper side. However, the present invention is not limited to this, and a configuration in which the upper end of the metal tube 11 is grounded on the bottom surface of the metal box 10 and the height of the metal tube 11 is provided on the lower side may be obtained, and similar effects can be obtained. .

Embodiment 4 FIG.
In the fourth embodiment, an antenna device capable of increasing the radiation amount in the radiation region as compared with the second embodiment will be described.
FIG. 8 is a sectional view showing a configuration of an antenna apparatus according to Embodiment 4 of the present invention. The antenna device according to Embodiment 4 shown in FIG. 8 is obtained by adding a capacitor 12 to the antenna device according to Embodiment 2 shown in FIGS. Other basic configurations are the same, and only the different parts will be described with the same reference numerals.

In the antenna device according to the fourth embodiment, as shown in FIG. 8, a capacitor 12 that short-circuits the bottom surface of the metal box 10 and the dielectric tube 2 at a high frequency is provided. At this time, the distance from the position where the capacitor 12 is provided to the position where the metal pins 6 and 7 are inserted into the dielectric tube 2 is about ¼ of the wavelength of the high frequency.
In installing the capacitor 12, for example, first, a new metal pin is inserted into the dielectric tube 2 at a position close to the bottom surface of the metal box 10. And it comprises by making the bottom face of the metal box 10 and the dielectric tube 2 conduct | electrically_connect in high frequency through the filter similar to FIG. In this case, in the filter in this case, the length of the portion where the lines on both sides of the dielectric substrate overlap is set to about ¼ of the in-tube wavelength of the high frequency used.

  Next, the operating principle of the antenna device according to Embodiment 4 shown in FIG. 8 will be described. Here, the operation when the plasma excitation power source 5 is OFF is the same as the configuration of the first embodiment, and only the case where the plasma excitation power source 5 is ON will be described below.

  In the antenna device according to the fourth embodiment, the dielectric tube 2 serving as the plasma conductor is short-circuited with the ground conductor 1 by the capacitor 12 that conducts at a high frequency. Therefore, the ideal impedance becomes infinite at a position about 1/4 of the wavelength of the high frequency from the shorted position. Therefore, the current that branches from the position where the metal pins 6 and 7 are inserted into the dielectric tube 2 to both ends (lower side) of the dielectric tube 2 hardly propagates to the dielectric tube 2. Therefore, the amount of radiation outside the radiation region decreases, and the amount of radiation in the radiation region increases.

  As described above, according to the fourth embodiment, the capacitor 12 that short-circuits the bottom surface of the metal box 10 and the dielectric tube 2 at a high frequency is provided. It becomes possible to increase more.

Embodiment 5. FIG.
In the fifth embodiment, an antenna device capable of increasing the radiation amount in the radiation region as compared with the first to fourth embodiments will be described.
FIG. 9 is a sectional view showing a configuration of an antenna apparatus according to Embodiment 5 of the present invention. The antenna device according to the fifth embodiment shown in FIG. 9 is obtained by adding a metal box 10, a metal cylinder 11, and a capacitor 12 to the antenna device according to the first embodiment shown in FIG. Other basic configurations are the same, and the same reference numerals are given and description thereof is omitted.

  Thus, with respect to the configuration of the first embodiment, the metal box 10 that is the point of the configuration of the second embodiment, the metal cylinder 11 that is the point of the configuration of the third embodiment, and the configuration of the fourth embodiment. By using together the capacitor 12 which is the point, it is possible to further reduce the radiation amount to the outside of the radiation region and further improve the radiation efficiency of the radiation region as compared with the first to fourth embodiments.

Embodiment 6 FIG.
In the sixth embodiment, an antenna device capable of increasing the radiation amount in the radiation region as compared with the second embodiment will be described.
FIG. 10 is a sectional view showing a configuration of an antenna apparatus according to Embodiment 6 of the present invention. The antenna device according to the sixth embodiment shown in FIG. 10 is obtained by adding a metal box 10b to the antenna device according to the first embodiment shown in FIG. Other basic configurations are the same, and only the different parts will be described with the same reference numerals.

  In the antenna device according to the sixth embodiment, as shown in FIG. 10, the metal box 10 b that covers both ends (lower side) of the ground conductor 1 of the dielectric tube 2, the metal pins 6, 7 and the electrode terminals 3, 4 is provided. Is provided. The metal box 10b is a box-shaped member having an upper surface opened, and the upper end is grounded to the lower surface (lower surface) of the ground conductor 1. In addition, a hole 1003 through which a wiring connecting the lead wires 302 and 402 and the plasma excitation power source 5 passes is provided on the bottom surface of the metal box 10b. Further, a notch groove (which may be a hole) 1002 through which the feeder line 9 passes is provided on the side surface of the metal box 10b. Note that the size of the hole 1003 and the notch groove 1002 is as small as possible.

  Next, the operation principle of the antenna device according to Embodiment 6 shown in FIG. 10 will be described. Here, since the principle of operation as an antenna is the same as that of the second embodiment, only the parts different from the above will be described. Hereinafter, only the case where the plasma excitation power source 5 is ON will be described.

  In the antenna device shown in the second embodiment, the radiation from the dielectric tube 2 extending below the metal box 10 deteriorates the radiation efficiency in the radiation region. On the other hand, in the sixth embodiment, as shown in FIG. 10, the dielectric tube 2 is configured to be accommodated in the metal box 10b. Therefore, there is no amount that the dielectric tube 2 radiates radio waves outside the radiation area. And the electromagnetic wave from the dielectric tube 2 is radiated | emitted in the metal box 10b, and is stopped in the metal box 10b. The radio waves accumulated in the metal box 10b leak into the radiation region from the hole 101 provided in the ground conductor 1 and excite the plasma conductor. Therefore, it contributes to the improvement of radiation efficiency in the radiation region.

  As described above, according to the sixth embodiment, the metal box 10b that covers both ends of the dielectric tube 2 from the ground conductor 1 and the metal pins 6 and 7 and is grounded to the ground conductor 1 is provided. Compared to mode 2, the amount of radiation in the radiation region can be further increased.

  As described above, in all the embodiments, when the plasma excitation power source 5 is ON, it operates as an antenna, and when the plasma excitation power source 5 is OFF, matching is difficult, so that the radiation amount as an antenna becomes extremely small, and the surroundings It becomes an antenna apparatus which can reduce interference with the antenna arrange | positioned.

  Further, in the prior art, as the frequency increases, the electrode terminal for plasma excitation becomes finer, and only a small electric power can be supplied to excite the plasma, and the loss of the plasma conductor is large. On the other hand, in all the embodiments of the present invention, since the size of the electrode terminals 3 and 4 for plasma excitation does not depend on the frequency, high power can be supplied to excite plasma. Therefore, the loss of the plasma conductor is small, and the operation as an antenna is possible without causing a decrease in the amount of radiation in the radiation region.

  In addition, by providing the filter 905 in the high-frequency feed line, application of a high voltage to the high-frequency power source 8 is prevented and stable plasma generation is enabled.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 Ground conductor, 2 Dielectric tube, 3, 4 Electrode terminal, 5 Plasma excitation power supply, 6, 7 Metal pin, 8 High frequency power supply, 9 Feeding line 10, 10b Metal box, 11 Metal cylinder, 12 Capacitor, 101 hole, 201 Folded part, 301, 401 Discharge electrode, 302, 402 Lead wire, 901 Dielectric substrate, 902 Ground pattern, 903 line (first line), 904 line (second line), 905 filter, 1001, 1003 hole , 1002 Notch groove.

Claims (4)

With ground conductors,
A dielectric tube having an ionizing gas inside, having a folded portion, and penetrating the ground conductor so that the folded portion and both ends are arranged with the ground conductor as a boundary,
Electrode terminals provided at both ends of the dielectric tube;
A plasma excitation power source connected to the electrode terminal to bring the ionizable gas into a plasma state;
At the both ends of the dielectric tube from the ground conductor, metal pins inserted into the dielectric tube,
A high frequency power supply for supplying high frequency power to the metal pin;
A feed line that has a filter that cuts off a low frequency band, and connects the metal pin and the high-frequency power source at a high frequency through the filter;
A metal box covering the metal pin and grounded to the ground conductor;
An antenna device comprising: a metal tube that surrounds the dielectric tube, is grounded to a bottom surface of the metal box, and has an upper end positioned on both ends of the dielectric tube with respect to the metal pin. The antenna device according to claim 1, further comprising a capacitor for short-circuiting the bottom and the dielectric tube of the metal box in a high frequency. With ground conductors,
A dielectric tube having an ionizing gas inside, having a folded portion, and penetrating the ground conductor so that the folded portion and both ends are arranged with the ground conductor as a boundary,
Electrode terminals provided at both ends of the dielectric tube;
A plasma excitation power source connected to the electrode terminal to bring the ionizable gas into a plasma state;
At the both ends of the dielectric tube from the ground conductor, metal pins inserted into the dielectric tube,
A high frequency power supply for supplying high frequency power to the metal pin;
A feed line that has a filter that cuts off a low frequency band, and connects the metal pin and the high-frequency power source at a high frequency through the filter;
A metal box covering the metal pin and grounded to the ground conductor;
The antenna apparatus provided with the capacitor which short-circuits the bottom face of the said metal box, and the said dielectric material tube at high frequency. The feeder line is composed of first and second lines formed on both surfaces of the dielectric substrate,
The filter, an antenna device according to any one of claims 1 to 3, characterized in that said first and second line is configured by being overlapped across the dielectric substrate.

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