TWI634833B - Terahertz-gigahertz system housing capable of minimizing interference and noise - Google Patents

Abstract

A housing in the terahertz-Girh system that minimizes foreign noise and inherently stray terahertz-Gird waves. The choice of housing material is based on the frequency range of the terahertz-Gird waves that will be conducted through the space surrounded by the housing. Generally, the casing is formed of a foamed material such as a foamed material having a low relative dielectric constant, particularly a foamed material having a conductive additive. The foamed material used typically has a relative dielectric constant of about 1.0, which in turn minimizes the reflection of terahertz-Gird waves that are transmitted into the casing. The use of conductive additives can increase the absorption of terahertz-Girsch waves (and even other electromagnetic waves) inside the casing. Obviously, by using suitable materials (such as expanded polypropylene and / or styrofoam) and using appropriate conductive additives (such as graphite, carbon, silver, absorbent particles and / or absorbent dyes) The housing minimizes interference caused by unwanted stray terahertz-jihs waves (and even other noise).

Description

Housing of a terahertz-Gird system to reduce interference and noise

The present invention relates to a terahertz-gigahertz system housing that can minimize interference caused by at least unwanted stray terahertz-gigahertz waves (terahertz-gigahertz system housing) a terahertz-Girsch system housing made of foam materials having a conductive additive, where the foamed material may be a commonly used expanded polypropylene ( Expanded Polypropylene/EPP) and Styrofoam and conductive additives can be commonly used graphite particles and carbon particles.

In the past few years, terahertz-gehz waves have been used in some applications. For example, terahertz-gehz waves have been used on security inspection tools because of the unique transport of terahertz-gehz waves. Quality can be used to identify hidden objects such as metal weapons hidden under fiber clothing. The terahertz-Girh system requires a housing to hold and/or connect components of the terahertz-Girsch system. The development of high-performance terahertz-Girsch systems (such as terahertz-Ghèz imaging systems and terahertz-Ghiz communication systems) depends on external electromagnetic noise and internal stray terahertz-ji Whether the internal stray terahertz-gigahertz wave is negligible. Such considerations are more important when the wavelength of the terahertz-Girsch wave (often a few millimeters) is comparable to the size of the components in a terahertz-Girsch system. Therefore, it is critical to be able to effectively reduce both the reflection from the inside of the system and the terahertz-Girh system housing that absorbs electromagnetic waves from outside the system.

To date, some conventional techniques have used uneven (non-smooth) surfaces to reduce the reflection of incident electromagnetic waves. By way of example only, a surface that is not flat and has many pin-like structures or a plurality of wedge-like structures may significantly modify the propagation of incident electromagnetic waves. Some conventional techniques use special materials to reduce the reflection of incident electromagnetic waves and enhance their absorption. For example only, an electrically insulating and silicone based elastomer (elastomer) comprising a polymer at room temperature Polymerizing an aromatic/arophatic hydrocarbon, an electrically insulating material, a siliceous filler, with an inert gas instead of polysiloxane. And a curing agent. Some of the prior art are disclosed in US Pat. No. 7,940,204, US Pat. No. 6,674,609, US Pat. In any case, all of these conventional techniques are not yet suitable for making scalable (complex according to their size and structure), lightweight, compact, robust and inexpensive. The terahertz-Girsch system housing that minimizes interference caused by at least unwanted stray terahertz-Gird waves can be minimized.

In summary, there is a need to provide a terahertz-Girsch system housing that can minimize external noise and inherent stray electromagnetic waves in applications such as imaging, communications, or other future development applications.

The present invention proposes a housing for reducing noise and interference in a terahertz-Gird system. The present invention makes such a casing by using a special material to form a casing, and the materials used herein have specific electromagnetic properties. This allows the housing to effectively absorb as many terahertz-Gird waves as possible from only a multi-directional direction while minimizing internal reflections.

Some embodiments relate to forming a terahertz-Girsch system housing using a foamed material doped with absorptive particles/dyes (eg, conductive carbon and graphite), used herein. The material has a low relative dielectric constant (nearly 1.0). The electrically conductive particles/dyes can highly absorb stray electromagnetic waves from the exterior or interior of the casing, particularly stray terahertz-gehz waves that penetrate the casing of finite thickness. Incidentally, the low relative dielectric constant of the foamed material used can prevent harmful Fresnel reflections that may occur inside the casing, thereby reducing unwanted stray electromagnetic waves (especially stray terahertz - Ghiz wave).

The terahertz-Gird system housing proposed by the present invention has several advantages over other prior art techniques described above. First, the absorbent particles/dye can be incorporated into the shell material before or after the shell is formed, that is, the size, shape and manufacturing process of the shell are not limited by the use of absorbent particles/dyes. Second, the doped absorbent particles / dyes The percentage can be adjusted precisely and elastically to change the properties of the terahertz-Girsch system housing. Incidentally, because the absorbent particles/dye are integrated into the housing, external retroreflection and absorption layers/structures that complicate the housing structure are not necessary.

100‧‧‧THz-Ghiz system

101‧‧‧ cylindrical shell

102‧‧‧ lenses

103‧‧‧ lenses

104‧‧‧left opening

105‧‧‧ right opening

106‧‧‧THz-Ghiz communication system

107‧‧‧Shell

108‧‧‧transmitter

109‧‧‧ Receiver

110‧‧‧THz-Ghzwave

210‧‧‧Steps

220‧‧‧Steps

230‧‧‧Steps

The first A and the first B are two examples of the terahertz-Gird system housing; the second is a flow chart for implementing some basic steps of the present invention; and the third is a test for the material of one example of the present invention. The results; and the fourth figure are the basic concepts, basic components and some example components of the shell material used in the present invention.

The detailed description of the present invention will be discussed by the following examples, which are not intended to limit the scope of the invention, and are applicable to other applications. The drawings disclose some details, and it must be understood that the disclosed details may differ from those disclosed, unless the features are explicitly limited.

A THz system typically requires a specific housing to hold and/or connect its components. Generally, the housing surrounds a space and has at least one opening to connect the enclosed space to the external space, and the different openings are separated from each other. For example, as shown in FIG. A, the terahertz-Girth system 100 has a cylindrical housing 101 and two lenses 102/103 that are respectively inside the cylindrical housing 101. Therefore, the terahertz-gehz wave reflected or transmitted from an object located on the left side of the cylindrical casing 101 can be sequentially sequentially transmitted through the left side opening 104, the lens 101, the lens 102, and the right side opening 105. The image sensor located on the right side of the cylindrical casing 101, that is, the terahertz-gehz image formed by the terahertz-gehz wave reflected or transmitted from the object can be formed into the cylindrical casing 101. Right. In another example, as shown in FIG. B, the terahertz-Girth communication system 106 has two housings 107 that are separated from each other by the transmitter 108 and the receiver 109, respectively. Therefore, the operation of both the transmitter 108 and the receiver 109 can be less affected by interference and noise due to the housing 107, respectively, and the terahertz-Gird wave 110 emitted by the transmitter 108 can be transmitted through The space between the two housings 107 reaches the receiver 109.

The present invention substantially reduces foreign and intrinsic terahertz-Gird noise. In particular, the material used in the formation of the casing of the present invention can hardly reflect any incident terahertz-Girsch waves (even other electromagnetic waves) and absorb almost all incident electromagnetic waves (including terahertz-Gird waves). .

A specific practice of the present invention to achieve the desired housing properties is to use at least one particular material, wherein the specific material has a relative dielectric constant of about 1.0 and the imaginary portion is non-negligible. Therefore, the Fresnel reflection on the surface of the casing can be greatly reduced. In other words, the reflection of terahertz-Girsch waves (or other electromagnetic waves) incident on the casing is negligible, but the absorption of terahertz-gehz waves (or other electromagnetic waves) cannot be ignored. Therefore, the housing can efficiently absorb terahertz-Gird-waves (or other electromagnetic waves) with very little reflection, so that the propagation of terahertz-jihz waves in the space surrounded by the housing is not disturbed by external noise or The impact of the inner noise.

The absorption of the side wall of the shell depends on two functions of the absolute value of the imaginary part of the relative dielectric constant of the shell material and the thickness of the side body of the shell. The former determines the absorption rate and the latter determines Accumulative absorption. Therefore, in order to achieve the same amount of attenuation, the larger the absolute value of the imaginary part of the relative dielectric coefficient, the smaller the thickness of the casing required, and vice versa. As an example, the standard for an example is that electromagnetic waves (or terahertz-gehz waves) can achieve 30 dB (decibel) attenuation in a few centimeters of thickness as they pass through the sidewalls of the housing.

Certain embodiments of the present invention achieve the above-described desirable terahertz-Gieher system housing properties by using a foam material (s) because of its low relative dielectric constant. One advantage of using a foamed material is that many types of commercial foamed materials have had a low relative dielectric constant of about 1.0. For example only, expanded polypropylene and styrofoam are two commercial materials with low relative permittivity, and some types of expanded polypropylene have a relative ratio of nearly 1.0 to certain types of styrofoam. Electric constant. The present invention requires only the properties of a low relative dielectric constant but does not limit the foaming material used. Any foaming material that is already in existence, in development, and in the future may be used in the present invention.

Certain embodiments of the present invention achieve the desired terahertz-Gird system housing properties by using a foamed material doped with a conductive additive, wherein the details of the foamed material are as discussed above. Use conductivity to add One advantage of the materials is that these conductive additives can increase the absorption of terahertz-Gird waves and/or other electromagnetic waves. For example only, the conductive additive may be graphite or carbon, or even silver or other conductive material. By way of example only, the electrically conductive additive may be an absorbent granule or an absorbent dye, particularly an absorbent granule and an absorbent dye having a high dielectric loss. Of course, not only the size and shape of the conductive additive can be adjusted, but the ratio of the conductive additive to the foamed material can also be adjusted to fine tune its absorption/reflection properties. Further, as discussed above, the absorption coefficient and thickness of the housing are also dependent on the above adjustable items, and the doping amount of the conductive additive has an adjustable range.

In practice, the present invention also has a method for minimizing interference and noise in a terahertz-Girth system housing, minimizing the terahertz-Girsch system shell that does not require spurious terahertz-Gird-wave noise and interference. Body, or other similar application methods. As shown in the second figure, each method contains the following basic steps. First, as shown in step block 210, the frequency range of the terahertz-Gird electromagnetic waves intended to be transmitted through the terahertz-Gird system is confirmed, in particular, transmitted through the space surrounded by the housing of the terahertz-Girsch system. The frequency range of electromagnetic waves. Then, as in step block 220 Show that it is suitable for materials that do not reflect these terahertz-Ghz electromagnetic waves and absorb all other terahertz-Ghz electromagnetic waves. Finally, as shown in step block 230, the selected material is used to fabricate the housing of the terahertz-Gird system. Here, the choice of material is based on the electromagnetic properties of the material selected. It must be able to sufficiently absorb terahertz-gehitz waves and other electromagnetic waves from the external environment, absorb noise generated inside the material, and have a low relative dielectric constant to reduce reflection. Of course, whenever more than one material is qualified, usually only one of the qualified materials is used at a time, although it is also possible to use a mixture of at least two acceptable materials to make the housing of the terahertz-Girsch system. .

In addition to this, although not essential but advantageous, a preferred option is to use materials having high mechanical strength and high chemical stability. The high mechanical strength allows the housing to effectively hold and protect the components located inside the housing, and can have a robust structure that can be less deformed in the event of an impact. By way of example only, the so-called components may be lenses and/or sensors of a terahertz-Girsch imaging system, or may be transmitters and/or receivers of a terahertz-Ghz communication system. High chemical stability allows housing Can be used in many extreme environments. As an example only, the variables of these environments include at least temperature, humidity, and others. Incidentally, when the shell material is a foamed material and conductive particles/dyes, whether the conductive particles/dyes are simply and uniformly doped into the foamed material is also a material selection of the terahertz-Girsch system housing. One factor in the middle.

An example of the invention is a housing material that can effectively absorb terahertz-Gird waves having a frequency range of at least from 90 GHz to 96 GHz. The material of this example is a mixture of expanded polypropylene and carbon particles, wherein the weight percentage of carbon particles is about 13 to 15 percent. As shown in the third figure, the absorption strength of the material of this example is about fifteen dB per centimeter for the three different frequencies of 90 GHz, 93 GHz and 96 GHz, in which the horizontal axis represents The thickness is in centimeters, where the vertical axis represents power and the unit is dBm (decibel-meter). Obviously, by using such an example material, the thickness of the casing can be reduced to only fifty to four centimeters to achieve fifty dB of attenuation. Of course, thicker housings are also acceptable to enhance mechanical strength. Furthermore, although not specifically described herein, other examples/simulations have shown foamed materials (especially expanded polypropylene and foamed cotton) and conductive additives (especially carbon particles). And graphite particles) also have similar absorption intensities over a large frequency range, such as eighty to three hundred GHz, one hundred to five hundred GHz, and three to five hundred and fifty GHz. These non-specially described examples/simulations also show that the weight percentage of carbon particles can be about 0.1 to 3 percent, about 1 to 5 percent, and about 100 percent. From three to nine percent, about seven to three percent and about ten to fifteen percent. Of course, acceptable weight percentages of absorbent particles/dyes are a function of parameters including at least the density of the foamed material, the relative dielectric constant of the foamed material, and the thickness of the foamed material, even terahertz-Girsch The system housing is designed to handle the frequency range of the terahertz-Girsch wave. As an example only, the higher the weight percentage of carbon particles, the more absorption of terahertz-Girsch waves (and even other electromagnetic noise). Furthermore, in order to achieve the same degree of attenuation, the required housing thickness can be reduced.

Moreover, in order to further minimize unwanted Fresnel reflections occurring on the inner sidewalls of the housing, one or more options of the present invention are to provide the housing inner sidewall with no exposure that would cause additional internal noise due to scattering and/or reflection. The component, like it does not cause additional internal noise due to scattering and reflection from sharp corners or highly reflective surfaces. Housing The inner side walls may also be either smooth or textured, and the only restriction is that the geometrical configuration of the inner side walls does not result in additional interactions between the terahertz-gehz waves and the inner side walls. The inner noise. Incidentally, the details of these components (such as pipes or joints) depend on the details of the terahertz-Girsch system, but the invention is not related to these details. It should be noted that the density of the foamed material, such as the density of polyethylene, can also be adjusted. In general, the higher the density of the foamed material, the less air is present in the foamed material to form a higher reflectivity and heavier foamed material. Therefore, for a foamed material having a high density, the reflection of the terahertz-gehz wave will be relatively high. Under such conditions, the textured (or rough) terahertz-Girh system inner sidewalls can increase the number of bounces of the terahertz-gehz wave at the material interface (or as multiple The probability of reflection), in turn, leads to an increase in absorption and reflection of the terahertz-gehz wave. Again, this also means that interference and internal/external noise can be reduced.

Further, although the above discussion focused on the use of materials to fabricate terahertz-Girsch system housings, it can reduce interference and miscellaneous The electromagnetic properties of such materials that can be used to minimize interference and noise are independent of the geometry of the terahertz-Girsch system housing. In other words, the present invention does not require limiting the shape, size and position of the terahertz-Girtz system housing. Therefore, in addition to the above-described discussion of the case where the casing is used to surround the space through which the terahertz-Girsch wave will propagate, the terahertz-Girsch system shell proposed by the present invention is in other situations not specifically discussed. The body may also be a predetermined propagation path adjacent to (but not around) the terahertz-Girsch wave, and may even be integrated with any element of the terahertz-Girsch system. Therefore, regardless of the configuration of the terahertz-Girsch system housing, by using the materials discussed above to form the terahertz-Girsch system housing, the terahertz-Girsch wave noise and interference can always be minimized. Chemical. By way of example only, the outline of the terahertz-Girtz system housing may be a hollow shell having one or more openings, a cylindrical shell having one or more openings, having One or more open polygonal shells, a columnar shell with one or more openings, a curved surface with one or more openings, a planar surface without openings Planar surface, any contour with one or more openings, and any contour without any openings.

As a brief summary, the present invention proposes a terahertz-Girsch system housing using special materials that can simultaneously absorb at least stray terahertz-Gird waves and minimize stray terahertz-Gird wave reflections. As shown in the fourth figure, the basic concept of the material used is that the real part of its relative dielectric constant is about 1.0 and the absolute value of the imaginary part is large enough to cause high absorption; the basic composition of the material used is foamed material, especially It is a foamed material with a conductive additive; some examples of the materials used are: a mixture of polypropylene and carbon particles, a mixture of polypropylene and graphite particles, a mixture of styrofoam and carbon particles, and styrofoam Mixture with graphite particles.

Obviously, many modifications and differences may be made to the invention in light of the above description. It is therefore to be understood that within the scope of the appended claims, the invention may be The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the claims of the present invention; any equivalent changes or modifications made without departing from the spirit of the present invention should be included in the following patents. Within the scope.

Claims (32)

A terahertz-Girsch system housing, which is a terahertz-Gird system housing that minimizes interference caused by at least unwanted stray terahertz-Girsch waves; here, the material of the housing is almost It does not reflect terahertz-jihz waves and effectively absorbs terahertz-jihz waves. The terahertz-Gird system housing of claim 1, wherein the housing surrounds a space and has at least one opening connected to the enclosed space, wherein the terahertz-Girsch wave can be transmitted through the opening And entering or leaving is surrounded by space. The terahertz-Girsch system housing as described in claim 1 is designed for terahertz-Gird waves with frequencies between 80 GHz and 550 GHz. As described in the terahertz-Girsch system housing of claim 1, the thickness and material of the housing are designed to cause a terahertz-Girsch wave transmitted through the housing to have a decay of at least 30 dB. The terahertz-Girsch system housing of claim 1 is characterized in that the real part of the relative dielectric constant of the material used in the housing is approximately 1.0 and the absolute value of the imaginary part is large enough to cause a high degree of absorption. The terahertz-Girsch system housing according to claim 1, wherein the material of the housing is a foamed material. The terahertz-Girsch system housing according to claim 6, wherein the material of the housing is a foamed material having a low relative dielectric constant. The terahertz-Girsch system housing according to claim 1, wherein the material of the housing is a foamed material having a conductive additive. The terahertz-Girsch system housing according to claim 8, wherein the foaming material is selected from one of the following or any combination thereof: expanded polypropylene and styrofoam. The terahertz-Gird system housing according to claim 8, wherein the conductive additive is selected from one of the following or any combination thereof: graphite, carbon, Silver, absorbent particles and/or absorbent dyes. The terahertz-Girsch system housing as described in claim 10, both of the absorbent particles and the absorbent dye have a high dielectric loss. The housing of the terahertz-Gird system described in claim 6 is a conductive foamed polypropylene. The terahertz-Gird system housing according to claim 12, the conductive foamed polypropylene is a mixture of expanded polypropylene and carbon particles, and the carbon particles are about 13 to 100 percent by weight. Fifteenth. The terahertz-Gird system housing according to claim 12, wherein the conductive foamed polypropylene is a mixture of expanded polypropylene and carbon particles, wherein the weight percentage of the carbon particles is selected from the following One: about 0.1% to 3%, about 1% to 5%, about 3% to 9%, about 7 to 7%. Thirteen and about 10% to 15%. The terahertz-Girh system housing as described in claim 1 of the patent scope, The housing is formed using a material having a relatively low dielectric constant between 80 GHz and 550 GHz. The inner wall of the housing may be smooth or may be textured as described in the terahertz-Girsch system housing of claim 1. As described in the terahertz-Girth system housing of claim 1, the inner side wall of the housing does not have any exposed components that would cause additional internal noise due to scattering and/or reflection. The terahertz-Girsch system housing according to claim 1, wherein the housing has two separate openings so that the terahertz-Girsch waves can be sequentially transmitted through an opening, surrounded by space and another An opening. A method for minimizing interference and noise in a terahertz-Girsch system housing, comprising: confirming a terahertz-jihz wave frequency range corresponding to a housing of a terahertz-Girsch system; selecting at least one of which does not reflect this Terahertz-Girsch waves in the frequency range and terahertz-jihz that effectively absorb this frequency range The material of the wave; and the shell of the terahertz-Girsch system using the selected material. The method of claim 19, the corresponding terahertz-gehz wave frequency is about 80 GHz to 550 GHz. The method of claim 19, further comprising using a material having a relative dielectric constant of about 1.0 and an absolute value of the imaginary part being large enough to cause low reflection and high absorption to produce terahertz-ji The housing of the Hertz system. The method of claim 19, further comprising selecting the thickness and material of the housing such that the terahertz-Girsch wave transmitted through the housing has a decay of at least 30 dB. The method of claim 19, further comprising using a foamed material, such as a foamed material having a low relative dielectric constant, in the fabrication of the casing. The method described in claim 19, which is further included in the production of the shell A foamed material having a conductive additive is used in the body. The method of claim 24, wherein the foamed material is selected from one of the following or any combination thereof: expanded polypropylene and styrofoam. The method of claim 24, wherein the electrically conductive additive is selected from one of the following or any combination thereof: graphite, carbon, silver, absorbent particles, and/or an absorbent dye. The method of claim 26, wherein both the absorbent particles and the absorbent dye have a high dielectric loss. The method of claim 19, further comprising using conductive foamed polypropylene in the production of the casing. The method of claim 28, wherein the electrically conductive foamed polypropylene is a mixture of expanded polypropylene and carbon particles, wherein the weight percentage of the carbon particles is about 13% to 100%. Fifteen. The method described in claim 28, wherein the conductive foam Polypropylene is a mixture of expanded polypropylene and carbon particles, wherein the weight percentage of the carbon particles is selected from one of the following: about 0.1% to 3%, about 1% to Five percent, about three to nine percent, about seven to three percent, and about ten to fifteen percent. The method of claim 19, further comprising using a material having a low relative dielectric constant with respect to the terahertz-Girsch wave of the frequency range in the fabrication of the housing of the terahertz-Gird system. The method of claim 19, wherein the housing of the terahertz-Girth system surrounds a space and has at least one opening connected to the enclosed space, wherein the terahertz-Girsch wave can pass through the opening Being transmitted into or out of this is surrounded by space.