A magnetron which generates a high-frequency energy in the Terahertz band is provided. The magnetron includes a cathode unit, which is connected to a terminal of a power source, and which selectively emits an electron according to when power is supplied; an anode block, which is connected to another terminal of the power source, and which has an operation chamber in which the emitted electron moves; and one or more resonance cavities which generate a high-frequency energy by a movement of the emitted electron; and a pair of magnet units forming a magnetic field in the operation chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2004-0113121 filed on Dec. 27, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a magnetron. More particularly, the present invention relates to a magnetron that can generate a high frequency energy of the Tera Hertz (THz) band.

2. Description of the Related Art

The magnetron generates a high-frequency energy and is widely used in home appliances such as a microwave oven, as well as in industrial applications, such as the areas of data signal transmitting, medicine, and biotechnology.

Briefly looking into the structure and principle of magnetrons, a magnetron generally comprises a cylindrical positive pole, a negative pole on a central axis of the cylindrical positive pole, a magnet which forms a magnetic field in parallel with the axis direction of the negative pole, and a resonance cavity for generating a resonance of electric current. When a high voltage is supplied to the negative and positive poles of the magnetron with the above structure, electrons are emitted from the negative pole. The electrons collide with the resonance cavity, moving in a cycloid, due to interaction between an electric field and the magnetic field of the negative and positive pole, such that an electric current flows. Due to the continuous collision of electrons, the electric current is oscillated in the resonance cavity. The resonance cavity is electrically equivalent to a series circuit of an inductor and a capacitor, and if the frequency of the electric current is accorded with a resonance frequency of the series circuit, a high-frequency energy is generated that is an electromagnetic wave of the resonance frequency of high frequency. The high-frequency energy is picked up by a coupling iris and emitted by an antenna to a necessary place.

The energy produced in accordance with the above principles has a frequency of approximately 95 GHz and below. However, a study has recently increased the frequency of the energy generated from a magnetron to an energy band that is potentially in the Terahertz region (e.g., 300 G Hz˜3 THz).

To increase the frequency of the energy, a large amount of electric current may flow to the negative pole. However, the negative pole may be easily deteriorated as the temperature thereof rises. Further, the negative pole may be damaged as emitted electrons return towards the negative pole and collide with the negative pole. Therefore, such conventional methods shorten the lifespan of the negative pole. Recently, a study has obtained a higher frequency by reducing the resonance cavity.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention has been conceived to solve the above-mentioned problems occurring in the prior art, and disadvantages not described above. Also, the present invention is not required to overcome the disadvantages described above, and an exemplary embodiment of the present invention may not overcome any of the problems described above.

An aspect of the present invention is to provide a magnetron that can generate energy in the Terahertz (THz) band.

Another aspect of the present invention is to provide a magnetron that can be microminiaturized.

According to an exemplary embodiment of the present invention, there is provided a magnetron comprising: a cathode unit connected to a terminal of a power source and selectively emitting an electron according to whether a power is supplied, an anode block connected to the other terminal of the power source and having an operation chamber with the emitted electron moving therein and at least one resonance cavity generating a high frequency energy by a movement of the electron, and a pair of magnet units forming a magnetic field in the operation chamber.

The cathode unit comprises a cathode electrode, and a nano-tube formed on an outer circumference of the cathode electrode.

According to an exemplary embodiment of the present invention, the resonance cavity comprises a plurality of resonance cavities, which are radially arranged at regular intervals on the basis of the operation chamber. The operation chamber and the resonance cavity are cylindrical. The anode block has a plurality of connection slots fluidly communicating with the resonance cavity and the operation chamber, and an emission part picking up the high frequency energy and emitting the energy to a necessary place. The emission part comprises a coupling iris fluidly communicated with at least one of the resonance cavities, and a waveguide fluidly communicated with the coupling iris. A sealing member is attached to the anode block to airtightly seal the waveguide, and comprises an insulator. The anode block comprises a first and a second anode block with same configurations at facing surfaces. The first and the second anode blocks are made of a silicon substrate, and a conductive layer is deposited on surfaces that face each other. The conductive layer comprises aurum (Au). The plurality of magnet units comprise a first and a second magnets respectively attached to opposite surfaces of the facing surfaces of the first and the second anode blocks and having first and second magnet connection holes in each center; and a first and a second sleeves of which part is inserted into the first and the second magnet connection holes, and of which the remaining part is inserted into first and second connection holes formed on both sides of the operation chamber, and in which both sides of the cathode unit are inserted. The first and the second sleeves are nonconductors.

According to another exemplary embodiment of the present invention, the pair of magnet units comprises a first and a second magnets with different magnetic poles; and first and second plates having first and second receiving parts receiving the first and the second magnets, and attached to both sides of the anode block. The anode block is made of conductive material.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals throughout the drawings. In the following description, detailed descriptions of known functions and configurations incorporated herein have been omitted for conciseness and clarity.

Referring toFIGS. 1 and 2, a magnetron according to an exemplary embodiment of the present invention comprises an power source100, a cathode unit110, an anode block120, a pair of magnet units140,150, and a sealing member160.

A terminal of the power source100is connected to the cathode unit110, and the other terminal of the power source100is connected to the anode block120so as to supply a high voltage to the cathode unit110and the anode block120.

The cathode unit110comprises a cathode electrode112connected to a terminal of the power source100, and a nano-tube114on an outer circumference of the cathode electrode112. The cathode electrode112is made of a conductive material, and formed at the anode block120. The nano-tube114is spread on the outer circumference of the cathode electrode112according to Chemical Vapor Deposition (CVD) so as to be located in an operation chamber122of the anode block120. The nano-tube114is made of a conductive material such as a carbon nano-tube, and emits electrons by means of an electric field formed between the cathode electrode112and the anode block120. The nano-tube114emits electrons to the operation chamber122, which will be explained below, by so-called Field Emission Effect.

The anode block120comprises a first anode block120aand a second anode block120b. The first anode block120aand the second anode block120bare combined to provide a single anode block120. The first anode block120aand the second anode block120btake on the symmetrical configuration with respect to each other.

In the first and the second anode blocks120a,120b, the operation chamber122, the resonance cavity124, and an emission part130are provided.

The cylindrical operation chamber122is formed in the center of the anode block120. The nano-tube114is located in the center of the operation chamber122so that electrons emitted from the nano-tube114can move. The operation chamber122has first and second connection holes137and138to mount the cathode unit110and the magnet units140and150thereto.

In this exemplary embodiment, eight cylindrical resonance cavities124are radially arranged at regular intervals along the operation chamber122. However, the number and configuration of the resonance cavities124are not limited as set forth above, and various numbers of resonance cavities and various configurations may be applied as required. Between each of the resonance cavities124and the operation chamber122, connection slots126are formed for allowing the resonance cavities124to fluidly communicate with each other.

The emission part130comprises a coupling iris132and a waveguide134.

The coupling iris132is provided in a form of a small slot fluidly communicated with one of the eight resonance cavities124, and the coupling iris132picks up a high-frequency energy generated from each of the resonance cavities124.

The waveguide134is fluidly communicated with the coupling iris132, and guides the high-frequency energy picked up from the coupling iris132to the necessary place.

An exemplary manufacturing process of the anode block120will be explained hereinafter. First, a silicon ingot is cut to make the first anode block120aand the second anode block120b. A mask is patterned except for the configurations of the operation chamber122of the first anode block120a, the first and the second connection holes137,138, the resonance cavities124, the connection slot126, and the emission part130. The operation chamber122, the first and the second connection holes137and138, the resonance cavities124, the connection slot126, and the emission part130are etched according to a Reactive Ion Etching (RIE). A conductive material is deposited onto a surface of the etched first anode block120ato form a conductive layer136. The conductive layer136is formed to the operation chamber122, the first and the second connection holes137and138, the resonance cavities124, the connection slot126, the emission part130, and the unetched portion of the first anode block120a. In other words, the conductive layer136is formed on a surface of the first anode block120afacing to the second anode block120b. The conductive layer136may be made of aurum (Au), for example, with a high conductivity. The conductive material is deposited because the first anode block120a, which is formed from silicon, is nonconductive.

The second anode block120btakes on the symmetrically same configuration of the first anode block120a, and therefore, the manufacturing process of the first anode block120ais once repeated to form the second anode block120b.

Then, the first and the second anode blocks120aand120bare combined with each other by the above process. The anode block120is manufactured according to a semiconductor fabrication process so that each of the resonance cavities124can be manufactured with a small size of about several tens of micrometers in diameter and the small size allows the resonance cavities124to generate a high frequency energy in the Terahertz band.

The pair of magnet units140and150comprise a first magnet unit140attached to a surface of the first anode block120a, and a second magnet unit150attached to a surface of the second anode block120b.

The first magnet unit140comprises a first magnet142and a first sleeve144. The first magnet142has a first magnet connection hole143in the center to engage with the first sleeve144. The first sleeve144is inserted into the connection hole137and the first magnet connection hole143, and an end of the cathode electrode112is inserted and fixed into the first sleeve144. The first sleeve144prevents the cathode electrode112and the first anode block120afrom electrically connecting to each other. In particular, the first sleeve144electrically separates the cathode electrode112and the conductive layer136of the first anode block120afrom each other.

The second magnet unit150comprises a second magnet152with a second magnet connection hole153in the center and a second sleeve154, which are the same as those of the first magnet unit140. The second magnet152has a magnetic pole that is opposite to that of the first magnet142. In other words, if the first magnet142has a “N” magnetic pole, the second magnet152has a “S” magnetic pole so as to form a magnetic field, which is in parallel with a center axis of the cathode unit110in the operation chamber122. The second sleeve154is inserted into the second magnet connection hole153in the center of the second magnet152and the second connection hole138of the second anode block120bin the same manner as that of the first sleeve144. The other end of the cathode electrode112is inserted into the second sleeve154.

The sealing member160attaches to one side of the anode block120with the waveguide134so as to form an airtight seal with the operation chamber122and the resonance cavity124so as to maintain a vacuum state. The sealing member160is made of dielectric material through which the high-frequency energy emitted via the waveguide134can pass and which is an electrical insulator.

With reference toFIG. 3, the operation principle of the magnetron according to an exemplary embodiment of the present invention will be explained hereinafter.

Referring toFIG. 3, a high voltage is supplied from the power source100(refer toFIG. 2) to the conductive layer136of the anode block120, and to the cathode electrode112. Electrons are emitted from the nano-tube114on the outer circumference of the cathode electrode112. The emitted electrons move towards an inner surface128of the operation chamber122, moving in a cycloid due to the magnetic field and the electric field. The magnetic field is formed in parallel with the center axis of the cathode electrode112in the operation chamber122by the first and the second magnets142and152(referring toFIG. 2), and the electric field is formed in the operation chamber122by the cathode electrode112and the anode block120. The electrons collide with the conductive layer136on the inner surface128of the operation chamber122. The electric current oscillates in the conductive layer136on the inner surface128of the resonance cavities124as a plurality of electrons collide with the conductive layer136of the inner surface128with time intervals. The resonance cavities124are electrically equivalent to the series circuit of a capacitor and an inductor so that the oscillation of the electric current reaches the resonance frequency of the resonance cavities124. A high resonance frequency in the Terahertz band is formed due to the small size of the resonance cavities124, which have a diameter of approximately several tens of micrometers so that the high frequency energy in the Terahertz band is generated. The high-frequency energy is generated in each of the resonance cavities124, and is picked up by the coupling iris132. The picked-up high-frequency energy is transmitted to a necessary place by the waveguide134. The sealing member160is made of material through which the high frequency energy can pass, and an electrical nonconductor, so as to not block the emission of the high-frequency energy.

FIG. 4andFIG. 5depict a magnetron according to another exemplary embodiment of the present invention. The magnetron according to the exemplary embodiment of the present invention shown inFIG. 4andFIG. 5differs from the magnetron according to the first exemplary embodiment in that an anode block220is a single layer, the anode block220is made of conductive material, and dedicated first and second plates244and254are used to cover both sides of the anode block220. The magnetron according to the exemplary embodiment of the present invention shown inFIG. 4andFIG. 5will be explained in detail hereinafter.

The magnetron according to the exemplary embodiment of the present invention shown inFIG. 4andFIG. 5comprises a power source200, a cathode unit210, an anode block220, a pair of magnet units240and250, and a sealing member260.

The power source200, the cathode unit210, and the sealing member260have the same structure as those described with respect to the first exemplary embodiment of the present invention, and therefore, detailed description thereof will be omitted.

The anode block220comprises an operation chamber222, connection slots226, resonance cavities224, a coupling iris232, and an emission part230with a waveguide234, which are the same as those according to the first exemplary embodiment of the present invention. The configurations, sizes, and positions of the aforementioned features are the same as those of the first exemplary embodiment of the present invention, and therefore, detailed description thereof will be omitted. However, according to the exemplary embodiment shown inFIG. 4andFIG. 5, it is not necessary to form a dedicated conductive layer since the anode block220is made of conductive material in a different way from the first exemplary embodiment of the present invention.

The pair of magnet units240and250comprises a first magnet unit240and a second magnet unit250.

The first magnet unit240comprises a first magnet242and a first plate244having a first receiving part246for receiving the first magnet242. The first magnet242has a first magnet connection hole243in the center, and the first receiving part246has a first connection hole248in the center of the first receiving part246. An end of the cathode unit210is inserted and fixed into the first magnet connection hole243and the first connection hole248in an airtight manner. The first plate244is attached to a surface of the anode block220. The first magnet242is located at an end of the operation chamber222.

The second magnet unit250comprises a second magnet252and a second plate254with a second receiving part256for receiving the second magnet252. The second magnet252and the second receiving part256have a second magnet connection hole253and a second connection hole258to insert the other end of the cathode unit210therein. The second plate254is attached to the other end of the anode block220. The second magnet252is located at the other end of the operation chamber222to face the first magnet242such that a magnetic field forms in parallel with a central axis of the cathode unit210in the operation chamber222.

The operation principle of the magnetron according to the exemplary embodiment of the present invention shown inFIG. 4andFIG. 5is as the same as that according to the first exemplary embodiment of the present invention, and therefore, detailed description thereof will be omitted.

If exemplary embodiments of the present invention are applied as described above, the resonance cavities124and224are manufactured according to a semiconductor fabrication process so that the resonance cavities124and224can be manufactured with diameter of several tens of micrometers, and the small size allows the resonance cavities to generate a high-frequency energy in the Terahertz band.

Additionally, according to exemplary embodiments of the present invention, the magnetron is manufactured according to the semiconductor fabrication process so as to be microminiaturized to several hundred micrometers.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made to the exemplary embodiments of the invention without departing from the spirit and scope of the invention as defined by the appended claims.