CZ26489U1 - Microwave antenna with integrated function of organic vapor sensor - Google Patents

Description

Microwave antenna with integrated organic vapor sensor function

Technical field

The invention relates to a microwave antenna with an integrated organic vapor sensor function, in particular to a ground plane microstrip antenna for transmitting information in wireless networks, the second function of the antenna being the possibility of detecting organic vapor. BACKGROUND OF THE INVENTION

At present, antennas of various designs are used in microwave bands. In the field of microstrip antennas, one can encounter, from a material point of view, antennas formed most often by thin copper, silver or other metal patches or just by layers of these metals deposited on an electrically non-conductive substrate (dielectric). These pads are in the form of structurally adapted structures (microstrip) for specific frequencies. The ground plane of the antenna is usually located on the back of the microstrip antenna. These antennas have a surface formed by a solid structure that is not able to react to changes in vapors found in the operating environment and therefore cannot be used for signal transmission and also for detection of organic vapors.

and? Nowadays, antennas with parts or layers based on carbon nanotubes are gaining ground.

The antenna according to Korean patent application KR 20090105991 is made of a polymer composite comprising carbon nanotubes in a polymer matrix based on polyamide (nylon).

The conductive material used in the antenna of Japanese Patent Application JP 2002109489 is a conductive paste composite comprising carbon nanotubes, a conductive metal powder and a polymer matrix.

US patent application 2005116861 relates to a small size antenna with a carbon nanotubes emitter having excellent functional characteristics in the high frequency band.

The subject of US patent application 2011220722 is an RFID tag antenna comprising a patterned layer on a substrate formed by interconnected segments of carbon nanotubes.

In the solution according to PCT International Patent Application WO 2012113322, a layer of carbon nanotubes is deposited on the surface of a solar panel, the function of which in this case is integrated with the photon capture function. This is an indication of a combination of multiple product features that carbon nanotube layers allow for their technological and utility properties. However, this combination of multiple functions is based on a combination of separate functions of its two components. However, insufficient attention has been paid to the more possible functions of the carbon nanotubes layer itself.

The essence of the technical solution

A microwave antenna with integrated sen35 function of organic vapor according to the present invention contributes to overcoming the above mentioned deficiency. The essence of the solution is that the antenna consists of a substrate of electrically non-conductive material in the shape of a sheet, on whose surface is applied an electrically conductive functional layer with the ability to receive / emit signals and concurrently reversible adsorption / desorption of organic vapor molecules nanotrubic. This functional layer is a filter cake on the filter membrane

4ii from polymeric nano fibers (a product of vacuum filtration of a carbon nanotube dispersion through a filter membrane of polymer nano fibers), either as a self-supporting functional layer or even with an integrated filter membrane.

The carbon nanotubes of the functional layer preferably have a diameter of 10 to 30 nm and a length of 1 to 10 µmη, and the functional layer preferably has a thickness of 30 µm to 500 µm. To increase sensitivity, the top of the functional layer may form its oxidation product.

- 1 GB 26489 U1

The microwave antenna with an integrated organic vapor sensor function according to the invention preferably takes the form of a flame or flame bikonic dipole. It can also be made in a miniaturized design such as a PIFA antenna. The shape and size of the antenna can be adjusted to the desired frequency.

So far, antennas capable of operating in the microwave band have not been described and at the same time can detect organic vapors by varying the resistance of the layer applied to the substrate used in the high-frequency technique. With the help of nanotubes it is possible to design an antenna which does not significantly influence its adaptation when organic vapors are detected. Such a solution is innovative in that more functions can be performed on a small area in the form of an antenna embedded in a mobile device, including the possibility of signal transmission and the possibility of detecting organic vapors. Structurally, it is not yet used technology of layer production, which is part of the substrate used in antenna technique for microstrip antennas. Thus, the antenna can simultaneously detect organic vapors in the atmosphere and after evaluation, notify the user of such a device that there is some type of organic vapor in the atmosphere, which is usually dangerous for human health even in larger and smaller concentrations. The evaluation itself is not performed by this antenna, in this case the antenna is understood as part of the chain, where it is in the chain at the position of the passive antenna and at the same time at the position of the sensor (sensor) of organic vapors. Clarification of drawings

In order to clarify the nature of the technical solution, the attached drawing shows:

FIG. 1 is an illustration of an antenna / organic vapor sensor;

Fig. 2 - illustration of antenna / organic vapor sensor - cross section;

Fig. 3 - wiring diagram of antenna / organic vapor sensor in the evaluation chain.

Examples of technical solutions

Example 1

The microstrip antenna in the exemplary embodiment (see Figs. 1 and 2) is comprised of a functional layer 2 of randomly entangled carbon nanotubes (MWCNT) of 1 to 10 µm in length and 10 to 30 nm in diameter. This functional layer 2 is deposited on an electrically non-conductive substrate 1 made of PMMA. The substrate 1 is formed by a 45 mm long and 9 mm wide strip anchored in the ground plane 4 formed by the PCB board. The thickness of the functional layer 2 is 200 μπι and is connected to the coaxial line 3. The antenna can be incorporated into the packaging of a portable device using wireless information transmission.

Functional layer 2 is a filter cake on the filter membrane of polymer nanofibers - it is made by vacuum filtration of an aqueous dispersion composed of carbon nanotubes and a mixture of surfactants through a polymer membrane. The filtering polymer membrane of polyurethane nanofibres is made by electrostatic spinning from a solution of polyurethane in dimethylformamide. The amount of dispersion corresponding to a thickness of 200 μην is filtered through this membrane. After reaching this thickness, the resulting layer is washed with alcohol and water to remove residual surfactants. The filter membrane is removed and the filtered layer is dried between filter papers. After drying, a suitable shape is created in this layer which corresponds to the frequency requirements of the antenna,

4d, in a particular case, a 9x45 mm strip. The strip is coated on a PMMA substrate. This formation is best adapted to the frequency of 1.28 GHz.

The resulting functional layer 2 is used as a self-supporting (filter nanofibrous membrane is separated), it is electrically conductive, capable of receiving / transmitting a signal. It is also capable of adsorbing organic vapor molecules upon melting these vapors. This process is reversible, ie when this layer is removed

4? organic vapors are desorbed from the vapors. Vapor adsorption and desorption can be easily detected by measuring the change in DC resistance. However, it is also possible to evaluate it by scalar measuring the reflection coefficient of the antenna formed from this resistive layer or by measuring the change in its resonance frequency, or by detecting a change in the resonant frequency of the antenna, without losing its function.

The above functions are realized by connecting an antenna / organic vapor sensor in the evaluation chain (see diagram in Fig. 3) in which the antenna A is connected via the converter P and the evaluation member V to the display D of the mobile device.

Example 2

The design of the antenna is similar to Example 1. The functional layer is again produced by vacuum filtration of an aqueous dispersion composed of carbon nanotubes and a mixture of surfactants.

The filter polymer membrane of polystyrene or polyamide 6 is made by electrostatic spinning from solution. The dispersion is filtered through these membranes. An amount corresponding to a functional layer 2 having a thickness of 30 µm is filtered. Upon reaching this thickness, the resulting layer is washed with alcohol and water to remove surfactant residues. The filter membrane is part of the resulting structure and is dried between filter papers. After drying, a suitable shape is created from this layer, which corresponds to the frequency requirements of the antenna, eg triangle, i? square and other formations as required by frequency. The resulting formation is then bonded to the non-conductive substrate i.

The size and shape is always dependent on the specific frequency for which the antenna is to be impedance matched. The antenna can be implemented without difficulty in unlicensed ISM bands, eg 2.45 GHz, 5.8 GHz, and it is also possible to manufacture and operate the antenna even in lower frequency bands. Antenna can

It can also be made in a miniaturized design such as a PIFA antenna.

Example 3

The construction of the antenna and its manufacture corresponds to Example 1 or 2. However, to increase the sensitivity, the surface of the functional layer 2 forms its oxidation product. Specifically, the functional carbon nanotubes layer 2 in this exemplary embodiment is subsequently functionalized by oxidation to increase the sensitivity.

Claims (6)

PROTECTION REQUIREMENTS Microwave antenna with integrated function of an organic vapor sensor, characterized in that it consists of a substrate (1) of an electrically non-conductive material in the form of a sheet, the surface of which is provided with an electrically conductive functional layer (2) reversible adsorption / desorption of organic vapor molecules, wherein the layer (2) is constituted on the basis of randomly entangled carbon nanotubes of the filter cake on the filter membrane of polymer nanofibres, either as a self-supporting functional layer or with an integrated filter membrane. Microwave antenna with integrated organic vapor sensor function according to claim 1, characterized in that the carbon nanotubes of the functional layer (2) have a diameter of 10 to 30 nm and a length of 1 to 10 µm. Microwave antenna with integrated organic vapor sensor function according to claim 1, characterized in that the functional layer (2) has a thickness of 30 µm to 500 µm. Microwave antenna with integrated organic vapor sensor function according to claim 1, characterized in that the surface of the functional layer (2) forms an oxidation product thereof for increasing the sensitivity. Microwave antenna with integrated organic vapor sensor function according to claim 1, characterized in that it is in the form of a flaming or flaming bikonic dipole. Microwave antenna with integrated organic vapor sensor function according to claim 1, characterized in that it is made in a miniaturized design such as a PIFA antenna.