Electric lamp and discharge devices: systems – Combined load device or load device temperature modifying... – Discharge device load with distributed parameter-type...
Reexamination Certificate
2002-12-12
2004-04-27
Clinger, James (Department: 2821)
Electric lamp and discharge devices: systems
Combined load device or load device temperature modifying...
Discharge device load with distributed parameter-type...
C315S005380, C313S039000
Reexamination Certificate
active
06727651
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a traveling wave tube, and more particularly to a traveling wave tube that is suitable for use in an antenna mounted on a satellite or in a transmitting device that employs a phased-array antenna.
2. Description of the Related Art
In the interest of minimizing heat loss in the collector and thus raising the efficiency of traveling wave tubes that are mounted in artificial satellites or traveling wave tubes that are used in phased-array antennas, a multistage collector structure is adopted in which the collector electrodes are divided into a plurality of units.
In a traveling wave tube having this type of multistage collector structure, different voltages are applied to the collector electrodes of each stage, and electron beams having a velocity distribution as a result of interaction with a high-frequency wave are discriminated and acquired according to the velocity of each.
FIG. 1
is a side view showing an example of the construction of a traveling wave tube, and
FIG. 2
is schematic sectional view showing the structure of a collector in the traveling wave tube shown in
FIG. 1
showing the relation between the high-voltage leads and the insulating ceramic parts. Further,
FIG. 3
is a sectional view showing the construction of an insulating ceramic part that is shown in FIG.
2
.
FIG. 2
shows a state in which high-voltage leads are routed through the lower-most portion of the insulating ceramic parts, but when four high-voltage leads pass through an insulating ceramic part as shown in
FIG. 3
, the high-voltage leads are not actually arranged at the lowermost portion but at positions that are slightly higher.
As shown in
FIG. 1
, the traveling wave tube is made up by: electron gun
50
having cathode
51
for emitting an electron beam; slow-wave circuit unit
60
made up by, for example, helix
61
; magnetic focusing unit
70
made up by a periodic magnetic field generation device; input unit
80
for receiving the high-frequency signal that is the object of amplification; output unit
90
for outputting the high-frequency signal that has been amplified; and collector
100
of multistage collector structure.
In this construction, the electron beam that is emitted from cathode
51
advances inside helix
61
while interacting with the high-frequency signal that has been received from input unit
80
. A high-frequency signal that has been amplified by interaction with the electron beam is then outputted from output unit
90
. The electron beam has an energy distribution, is applied to collector
100
, and is acquired at each collector electrode of collector
100
.
As shown in
FIG. 2
, collector
100
of a traveling wave tube of the prior art is a structure in which a plurality of collector electrodes (four stages in
FIG. 2
)
11
are each bonded and secured by insulating ceramic parts
12
in the radial direction of vacuum envelope
13
that is composed of metal. High-voltage leads
14
are connected to each collector electrode
11
to supply prescribed voltages from the outside, and these high-voltage leads
14
are routed to the outside through holes that are provided in insulating ceramic parts
12
.
As shown in
FIG. 3
, insulating ceramic parts
12
are of a construction formed in a cylindrical shape having uniform thickness in the radial direction so as to maintain a prescribed insulating capacity between vacuum envelope
13
, which is connected to the ground potential, and collector electrodes
11
, to which high voltages are applied; and in which a plurality of holes
15
are formed for routing the above-described high-voltage leads
14
. The central axis of the inside diameter substantially coincides with the central axis of the outside diameter of these insulating ceramic parts
12
.
In collector
100
of multistage collector structure, one high-voltage lead
14
passes through insulating ceramic part
12
that supports the first-stage collector electrode (C
1
in FIG.
2
), and two high-voltage leads
14
pass through insulating ceramic part
12
that supports the second-stage collector electrode (C
2
in FIG.
2
). Further, three high-voltage leads
14
pass through insulating ceramic part
12
that supports the third-stage collector electrode (C
3
in FIG.
2
), and four high-voltage leads
14
pass through insulating ceramic part
12
that supports the fourth-stage collector electrode (C
4
in FIG.
2
). In other words, high-voltage leads
14
do not pass through all of holes
15
provided in insulating ceramic parts
12
. Nevertheless, the same number of holes are provided at the same positions such that the same insulating ceramic parts
12
can be used at any stage in collector
100
of the prior art.
In addition, collector
100
shown in
FIG. 2
is a construction having an exhaust pipe attached (not shown in the figure), this exhaust pipe normally being affixed in an upper location of
FIG. 2
, and holes
15
for high-voltage leads in insulating ceramic parts
12
are therefore all formed on the lower side, as shown in FIG.
3
.
In recent years, however, there has been an ever-increasing demand for lighter and more compact traveling wave tubes for installation in artificial satellites or phased-array antennas.
In the collector in the above-described traveling wave tube, however, the thickness of the insulating ceramic parts in the radial direction must be equal to or greater than a prescribed thickness depending on the dielectric strength of the insulating ceramic material in order to maintain an insulative property between each of the high-voltage leads and between the collector electrodes and the vacuum envelope.
Reducing the thickness of insulating ceramic parts having holes for routing high-voltage leads has therefore been problematic, and it has been impossible to meet the demand for greater compactness using the construction of the prior art.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a traveling wave tube in which the diameter of the vacuum envelope is reduced to achieve greater compactness.
To achieve the above-described object, the insulating ceramic parts for insulating the collector electrodes and vacuum envelope in the traveling wave tube of the present invention are formed in a cylindrical shape in which the central axis of the inner diameter diverges from the central axis of the outer diameter. The traveling wave tube of the present invention is further constructed such that holes are provided in those portions having greater thickness in the radial direction, and the high-voltage leads for supplying prescribed voltages to the collector electrodes are routed through these holes.
By means of the above-described construction, the diameter of the vacuum envelope can be made smaller than in the prior art while maintaining a prescribed insulative property between each of the high-voltage leads as well as between the collector electrodes and the vacuum envelope.
A traveling wave tube that is more compact that the prior art can therefore be obtained, and in particular, the use of the traveling wave tube of the present invention in a system in which a multiplicity of antenna elements are arranged, such as in phased-array antenna, contributes greatly to making the system more compact.
The above and other objects, features, and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings, which illustrate examples of the present invention.
REFERENCES:
patent: 5177394 (1993-01-01), Kubo
patent: 6291935 (2001-09-01), Suzuki et al.
patent: 58-88762 (1983-06-01), None
patent: 04-359839 (1992-12-01), None
patent: 2001-118523 (2001-04-01), None
Japanese Office Action issued Aug. 13, 2003 (w/ English translation of relevation portion).
Nakagawa Hitoshi
Nemoto Akihiko
Nomoto Toshihiro
Alemu Ephrem
Clinger James
Dickstein Shapiro Morin & Oshinsky LLP.
NEC Microwave Tube, Ltd
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