RU2803289C1 - Device for bidirectional signal transmission of communication systems through a metal screen - Google Patents

Abstract

FIELD: radio communication systems.

SUBSTANCE: invention is intended for organizing bidirectional communication channels with devices located inside metal screens and can be used, for example, in medicine for exchanging data with implantable devices enclosed in a metal case; in robotics for data exchange with devices completely enclosed in a metal case. The device for bidirectional signal transmission of communication systems through a metal screen comprises two transceivers and two resonators placed on both sides of the screen. The first resonator is connected to the first transceiver, and the second one to the second transceiver. The resonators have a magnetic coupling coefficient k greater than the critical one. The central operating frequency of the device coincides with the frequency of the second maximum on the amplitude-frequency characteristic of the direct losses of the interacting resonators as measured without a screen.

EFFECT: bidirectional signal transmission of communication systems through a metal screen.

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Description

The invention relates to the field of radio communication systems and is intended for organizing bidirectional communication channels with devices located inside metal screens. The invention can be used, for example, in medicine for exchanging data with implantable devices enclosed in a metal case; in robotics - for exchanging data with devices completely enclosed in a metal case.

A device is known for organizing channels for bidirectional signal transmission [Sklyar, B. Digital communication. Theoretical foundations and practical application. Ed. 2nd, rev.: Trans. from English - M.: Williams Publishing House. - 2003. - 1104 p. (prototype)], containing two transceivers. A disadvantage of the known design (prototype) is the impossibility of exchanging data between devices in the case where one device is located in a completely closed metal screen or both devices are in different completely closed metal screens with one common wall.

The technical result of the claimed solution is to enable bidirectional transmission of communication system signals through a metal screen.

The claimed technical result is achieved by the fact that in a device for bidirectional transmission of communication system signals through a metal screen containing two transceivers, what is new is that it contains a screen, and on both sides of the screen two additional microwave resonators are placed, the first being connected to the first transceiver, and the second - to the second, while these two microwave resonators have a magnetic coupling coefficient k greater than the critical one, and the central operating frequency of the device approximately coincides with the frequency of the second maximum on the amplitude-frequency characteristic of direct losses of interacting microwave resonators, measured without a screen.

A comparative analysis with the prototype shows that the claimed device is distinguished by the presence of two microwave resonators located on both sides of the metal screen. Each microwave resonator is connected to its own transceiver. It is important that microwave resonators are located in such a way and have such characteristics that their magnetic coupling coefficient k is greater than the critical one, i.e. On the amplitude-frequency dependence of the transmission coefficient, measured without a screen, two signal transmission maxima are observed. In this case, the central operating frequency of the communication systems approximately coincides with the frequency of the second maximum.

Thus, the characteristics listed above that are distinctive from the prototype allow us to conclude that the proposed technical solution meets the “novelty” criterion.

The features that distinguish the claimed technical solution from the prototype are not identified in other technical solutions and, therefore, ensure that the claimed solution meets the “inventive step” criterion.

This invention is illustrated by drawings. In fig. 1 shows a device for bidirectional transmission of communication system signals through a metal screen. In fig. Figure 2 shows a section of a metal screen in the area where microwave resonators are located. In fig. Figure 3 shows the calculated dependences of the modulus of the system transmission coefficient for two cases: without a metal screen between the microwave resonators and with a screen. In fig. Figure 4 shows the modulus of the transmission coefficient and the modulus of the reflection coefficient at the operating frequencies of the system. In fig. Figure 5 shows the dependence of the skin layer thickness on frequency for various materials.

A device for bidirectional transmission of communication system signals through a metal screen contains (Fig. 1) two transceivers - (1) and (2), separated by a metal screen (3). Various design options are possible. For example, the metal screen (3) can be implemented in the form of a large metal sheet, the dimensions of which in the plane are orders of magnitude greater than the operating wavelength of communication systems. A case is possible when one of the transceivers, for example, the transceiver (1) is placed in a completely closed metal screen (4), and the transceiver (2) is located outside this screen - in open space. It is also possible that both the transceiver (1) is located in a completely closed metal screen (4) and the transceiver (2) is located in its own completely closed metal screen (5). In this case, metal screens (4) and (5) must have one common wall. On both sides of the metal screen (3) are placed (Fig. 2), for example, coaxial connectors (6) and (7), connected to microwave resonators (8) and (9). It is important to note that transceivers (1) and (2) can be connected (Fig. 1) both using waveguide structures to microwave resonators (8 and 9 in Fig. 2), and can be connected through a near electromagnetic field or through radio waves - using antennas. The microwave resonators (8) and (9) are separated by a metal partition (10), which is part of the screen (3). The thickness of the partition is selected comparable to the thickness of the skin layer in the selected material for a given frequency range. Thus, the integrity of the metal screen (3) is not compromised, one of the transceivers (1) or (2), or both transceivers (1) and (2) can remain in a completely enclosed metal screen. The design of microwave resonators (8) and (9) can be any and is selected based on the operating frequency range, as well as design considerations. For example, for the frequency range of 2.45 GHz, microwave resonators can be manufactured in stripline design. In this case, the parameters of the microwave resonators (8) and (9) and their location must be chosen in such a way as to ensure that the value of their magnetic coupling k is greater than the critical value, i.e. such that in the amplitude-frequency characteristic of direct losses, in the absence of a metal partition (10), two maxima of energy transfer will be observed. The operating frequency range corresponds to the second (high-frequency) maximum.

A device for bidirectional transmission of communication system signals through a metal screen operates as follows (Fig. 1). The signal from one of the transceivers (1) or (2) is supplied (Fig. 2) to the corresponding microwave resonator - (8) or (9). Since microwave resonators (8) and (9) are electromagnetically coupled oscillatory systems, the frequencies of their coupled oscillations are split. At the frequency of the lowest (first) oscillation mode, common-mode currents are induced in the metal partition (10) separating the microwave resonators (8) and (9), which leads to a high level of losses. While at the frequency of the second oscillation mode, antiphase currents are induced in the metal partition (10), which mutually cancel each other out - signals from transceivers (1) and (2) are transmitted to each other practically without attenuation.

The performance of the device for bidirectional transmission of communication system signals through a metal shield was evaluated using 3D numerical simulation. For this purpose, an electrodynamic model of the device was created for the frequency range of 2.45 GHz, including a closed cylindrical screen with an internal diameter of 4 mm and a height of 5 mm, in which the first microwave resonator was located. The second microwave resonator was placed openly on one of the flat walls of the first screen. Two identical microwave resonators are formed by copper strip conductors 1.2 mm wide and 3.7 mm long. One end of the strip conductors is shorted to ground, and the other is loaded with a capacitance of 2.2 pF. The distance between the inner surfaces of the strip conductors of the two microwave resonators is 0.3 mm, while the thickness of the screen is 200 μm, and the conductivity is 166 S/m. It is important to note that copper can be chosen as the screen material; in this case, the thickness of the screen due to a decrease in the skin layer depth should be approximately 0.3 microns. In fig. 3 and fig. Figure 4 shows the simulation results. Curve (11) shows the magnitude of the coefficient S ₂₁ . It can be seen that at frequencies above the passband there is significant signal attenuation up to the upper simulation frequency of 100 GHz. In practice, suppression of high-frequency signals up to optical frequencies is expected. Curve (12) shows the magnitude of the coefficient S ₂₁ for the case when there is no screen between the microwave resonators. It is clearly seen that such a system does not suppress signals at frequencies above the passband. Curves (13) and (14) in Fig. 4 shows modules S ₂₁ and S ₁₁ in the frequency region of the device bandwidth. The passband loss is less than 3 dB.

A device for bidirectional transmission of communication system signals through a metal screen satisfies the stated technical result, namely, it allows for bidirectional data exchange between devices located in metal screens. In addition, the device additionally suppresses high frequencies - up to the optical range. The device can be used to organize channels for transmitting digital information with implantable medical devices, with robotic platforms operating inside closed metal structures, etc. The scope of applicability of the invention is limited by the thickness of the skin layer in the screen material for the operating frequency range. For information, FIG. Figure 5 shows the dependence of the skin layer thickness on frequency for copper (15), nichrome (16) and for material (17) with a conductivity of 166 S/m, used in modeling the device. As can be seen, for example, for a copper screen with a wall thickness of 1 mm, the operating frequency should be no higher than 5 kHz, whereas with a copper wall thickness of 1 micron, signal transmission is possible at frequencies up to 1 GHz. In case of shielding using materials with low conductivity, the permissible thickness increases. For example, for a nichrome screen with a wall thickness of 1 mm, it is possible to operate at frequencies up to 250 kHz, and with a wall thickness of 10 microns - above 2 GHz. It should be noted that a given wall thickness can only be realized in the area where the resonators of the device are located.

Claims (1)

A device for bidirectional transmission of communication system signals through a metal screen, containing two transceivers, characterized in that two resonators are additionally placed on both sides of the screen, the first being connected to the first transceiver, and the second to the second, and these two resonators have a magnetic coupling coefficient k is greater than critical, and the central operating frequency of the device coincides with the frequency of the second maximum in the amplitude-frequency characteristic of direct losses of interacting resonators, measured without a screen.