KR101684081B1 - Microwave Hybrid Coupler Gas Sensor using Conducting Polymer - Google Patents
Microwave Hybrid Coupler Gas Sensor using Conducting Polymer Download PDFInfo
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- KR101684081B1 KR101684081B1 KR1020150042406A KR20150042406A KR101684081B1 KR 101684081 B1 KR101684081 B1 KR 101684081B1 KR 1020150042406 A KR1020150042406 A KR 1020150042406A KR 20150042406 A KR20150042406 A KR 20150042406A KR 101684081 B1 KR101684081 B1 KR 101684081B1
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- G—PHYSICS
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- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
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- C—CHEMISTRY; METALLURGY
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- C08L101/00—Compositions of unspecified macromolecular compounds
- C08L101/12—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/403—Cells and electrode assemblies
- G01N27/414—Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS
- G01N27/4141—Ion-sensitive or chemical field-effect transistors, i.e. ISFETS or CHEMFETS specially adapted for gases
Abstract
The present invention relates to a microwave hybrid coupler gas sensor using a conductive polymer material, and includes a hybrid coupler operating in a microwave band and having a plurality of transmission lines and a plurality of ports, wherein the plurality of transmission lines are made of metal, Wherein at least one of the transmission lines includes a sensing region composed of a conductive polymer on at least one of the ports.
Description
The present invention relates to a gas sensor, and more particularly, to a microwave hybrid coupler gas sensor using a conductive polymer material.
With the development of industrial technology, the use of chemical substances is becoming more frequent, and the degree of human body exposure to harmful chemicals is increasing, directly or indirectly. When the harmful chemical substance is solid or liquid, it has a visible form and it is easy to detect and block. However, because the harmful substance in the form of gas is invisible, it is impossible for the human body to directly detect it, do.
In addition, as the domestic and overseas energy consumption increases along with the economic growth, the amount of pollutants such as NO x and CO x , and volatile organic compounds (VOCs) such as benzene emitted during the use of fossil fuels is increasing, The amount is gradually accumulating.
Exposure to harmful gas in daily life is very persistent and repetitive, and there are many types of harmful gas. Compared to most of the gas detecting apparatuses developed so far, only a single noxious gas is inspected at one time.
The development of low-cost sensors for detection of noxious gas has been continued from various perspectives, but it has low selectivity for various kinds of noxious gas, and has problems in performance such as sensitivity and response speed.
Therefore, in order to reduce the damage caused by harmful gas including organic compounds and effectively cope with gas leakage in everyday life, it is necessary to develop a gas sensor having a high sensitivity selectively so that leakage of harmful gas can be detected early.
Development of a gas sensor with high sensitivity can be used for biochemical terrorism and development of a real-time detection sensor for harmful pathogens such as cholera, Salmonella, and Anthrax, which are harmful to human body by being parasitic to air conditioner and air conditioner The necessity of industrialization and civilization is increasing day by day.
Gas sensors for detecting harmful gases can be roughly divided into semiconductor type gas sensors, solid electrolyte gas sensors, contact combustion gas sensors, optical gas sensors, and the like, depending on their sensing principles. Each sensor has advantages and disadvantages, and yet it does not have a small noxious gas sensor with high sensitivity and selectivity at the same time.
In general, the hazardous gas sensor does not respond to only one specific gas but has low selectivity to various kinds of harmful gas. Therefore, there is a lack of research on the application to detect multiple gases at the same time.
In order to improve the performance of the semiconductor type gas sensor using the change in the conductivity of the metal oxide as an output signal, it is important to increase the surface reactivity. Therefore, there is a tendency to use a nano structure having a much higher surface area to the volume so that the reactivity with the noxious gas is high.
Since the Industrial Revolution, environmental pollution problems have been emerging all over the world. Especially, the problem of air pollution in urban environment has been attracting attention. As the environmental pollution in metropolitan areas becomes more serious, it causes various health problems. Therefore, various types of gas sensors for detecting toxic gases in the atmosphere are used, and most of the gas sensors currently use structures based on semiconductor devices based on nano thin films, nanowires, and conductive polymer compounds.
In particular, conductive polymeric compounds have advantages in that they are easy to modify and apply the electrical characteristics of materials, and are cheap. For this reason, it has been developed since the 1970s and has been used not only in gas sensors but also in various fields such as biology, medicine, and electrical and electronic fields. Conducting polymer compounds are mostly used for electric and electronic fields because they have excellent conductivity and can control process in nm size. On the other hand, in the case of conductive polymer compounds, when they are exposed to gas, they are bonded to gas molecules having excellent reactivity, and the molecular structure thereof changes, so that the conductivity and the work function of the material change. Therefore, this mechanism has been utilized in gas sensors.
Existing studies using polymeric compounds to date have been mainly representative of FET structures or nanowires operating on direct current. In the case of gas sensors in the AC phase, studies have been reported in which a polymer compound operating from tens of kHz to tens of MHz is formed into a thin film and applied to a resonator structure. However, gas sensors operating in such a direct current and low frequency range must be desorbed by heat treatment after gas adsorption. As a result, the detection time of the gas sensor is delayed, and there is a limit in terms of the quick response characteristic and the sensitivity.
An object of the present invention is to provide a gas sensor having a fast detection time, a low detection temperature, and excellent detection sensitivity.
In order to achieve the above object, the present invention provides a hybrid coupler operating in a microwave band and having a plurality of transmission lines and a plurality of ports, wherein the plurality of transmission lines are made of metal, And a sensing region composed of a conductive polymer on the side of the sensing region.
In the present invention, the hybrid coupler may be a four port 90 degree hybrid coupler including four transmission lines and four ports.
In the present invention, the sensing region may be formed on two adjacent ports of the four ports.
In the present invention, the sensing region may have a length of 1 to 10 mm, a width of 0.1 to 3 mm, and a thickness of 0.1 to 30 占 퐉.
The conductive polymer may be at least one selected from pentacene, polyaniline, polypyrrole, polythiophene, and derivatives thereof. Preferably, the conductive polymer is at least one selected from the group consisting of poly (3,4-ethylenedioxythiophene) Sulfonate).
In the present invention, the conductivity of the conductive polymer may be 0.1 to 1 x 10 5 S / m.
In the present invention, the conductive polymer doped with dimethyl sulfoxide may be used.
In the present invention, the sensing region may be formed by a spray coating method of a conductive polymer.
In the present invention, the gas may be at least one selected from organic phosphorus compounds, alcohols, carbon oxides, ammonia, nitrogen oxides, volatile organic compounds, oxygen, hydrogen, nitrogen and argon.
The detection sensitivity of the sensor according to the present invention may be 1 ppm or more, the detection temperature of the sensor may be 0 to 40 占 폚, and the detection time of the sensor may be 10 seconds or less.
The gas sensor according to the present invention has a fast detection time, low detection temperature, and excellent detection sensitivity by applying the conductive polymer material to the hybrid coupler operating in the micro-band. Therefore, it is possible to manufacture a highly sensitive, low-power, noxious gas sensor with low power consumption, high-temperature environment for improving reactivity, and high selectivity.
Figure 1 shows a gas detection mechanism.
2 shows the structure of a conductive polymer compound having a conjugated structure.
3 shows a structure of a gas sensor according to an embodiment of the present invention.
4 is a conceptual diagram of a gas sensor according to an embodiment of the present invention.
Figure 5 is an AFM image of a PEDOT: PSS film material.
6 is a photograph showing a gas sensor and a test fixture according to an embodiment of the present invention.
7 is a graph showing S-parameters measured using a gas sensor according to an embodiment of the present invention.
8 is a graph showing the phase response of S 21 according to gas exposure of a gas sensor according to an embodiment of the present invention.
9 is a graph showing changes in S 21 amplitude according to gas injection in a time domain measured using a gas sensor according to an embodiment of the present invention.
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
1. General gas detection mechanism
1 is a conceptual view showing a general gas sensor principle and a detection mechanism using a conductive polymer. The gas molecule distribution on the left side of the figure shows the general atmospheric state in which the gas molecules to be detected and other impurity molecules are present. At this time, in order to selectively detect only the gas molecules to be analyzed, a sensing material having high reactivity with a specific gas is used. In the present invention, a conductive polymer compound is used. The gas molecules and the conductive polymer compounds to be analyzed are adsorbed on the polymer compound due to their excellent reactivity. The adsorption phenomenon changes the electrical properties of the conductive polymer compound, and the transducer converts the chemical reaction into an electrical signal. By analyzing the finally converted electrical signal, the detection result for the desired gas can be obtained.
2. Detecting substances and mechanisms
In the case of a gas sensor using a conductive polymer material, conductivity is exhibited by a polaron and a free carrier moving along a polymer ring. Such a change in conductivity is mainly caused by surface adsorption by gas adsorption do. The change in sensitivity due to thickness change can also be explained by the change in conductivity. The thicker the sensing film, the lower the conductivity and the lower the sensitivity. The reason for this is that the total resistance change is small, and therefore the sensitivity is low, because it has a thick inner layer with a lower conductivity change than the surface layer where the conductivity change is large.
Conductive Polymer (CP) has high sensitivity, fast response time, and can operate at room temperature. Most existing studies using conductive polymers have focused on the resistance or current change of conductive polymers using field effect transistors (FETs) at the DC level. By applying a conductive polymer to a gas sensor based on a hybrid coupler, a highly sensitive, quick response gas sensor can be easily manufactured.
Since the conductive polymer has a very high volume-to-surface area ratio and is formed of a thin film layer, unlike other semiconductor type thick film gas devices or multilayer porous silicon gas devices, when the conductive polymer is used in a hybrid coupler based detection device, The thin film layer can be very sensitive to the partial pressure before reaching the state, and the adsorption reaction rate also occurs very rapidly. Conventional gas sensors have a low sensitivity of the sensor, and it is difficult to detect gas at a low concentration (tens of ppm or less). Further, since the resistance of the sensor is changed by another oxidizing gas and a reducing gas, selective sensing of the gas is limited.
The present invention provides a gas sensor that operates in a microwave band by combining a characteristic that electrical characteristics change when a conductive polymer material adsorbs a gas with a hybrid coupler. When the conductive polymer material is applied to the hybrid coupler, the frequency characteristics of the hybrid coupler change depending on whether the gas is adsorbed or not.
Examples of the conductive polymer include pentacene, polyaniline, polypyrole, polythiophene, and derivatives thereof. Particularly preferably, poly (3,4-ethylenedioxythiophene (Poly (3,4-ethylenedioxythiophene), PEDOT): poly (styrene sulfonate) (PSS). The weight ratio of PEDOT: PSS can be, for example, from 1: 1: 1 to 1: 5.
PEDOT: PSS, a derivative of polythiophene, is a conductive plastic material that has excellent stability in air and has high electrical conductivity at room temperature. PEDOT: PSS solution of water dispersion type is environmentally friendly solution process. In addition, PEDOT: PSS has a property of increasing the solubility and electric conductivity of a general organic solvent by a functional dopant. In the case of polypyrrole, the thermal stability, solubility and electrical conductivity are excellent. However, when the device is manufactured, the contact surface between the substrate and the sensing layer becomes poor and the coating on the substrate is poor. On the other hand, PEDOT: PSS is very suitable for use as a device because of its excellent adhension with the substrate. Therefore, in the present invention, it is ideal to use PEDOT: PSS as the conductive polymer.
When a conductive polymer is used as the conductive material, the sensing region may be formed by coating a solution containing a conductive polymer, a solvent, and the like on the substrate by a method such as spray coating or the like. The conductive polymer solution may include a dopant, and examples of the dopant include dimethyl sulfoxide (DMSO). The concentration of the conductive polymer in the solution may be, for example, 0.1 to 10 w / v%, and the concentration of the dopant may be, for example, 1 to 10 v / v%.
When the alkyl group, which is the hydrophobic tail of the alcohol gas molecule, is selectively adsorbed, such as ethanol gas, it interferes with the movement of freely moving carriers in the polymer chain, so that the conductivity of the sensing membrane is lowered and the sensitivity is also lowered.
However, in the case of PEDOT: PSS, electrons migrate through pi-orbital overlapping, which occurs when a single bond and a double bond of a typical carbon atom of a conductive polymer are crossed with each other when treated with a solvent DMSO. In the case of the sensing material PEDOT: PSS, the pie-orbital lapping becomes stronger by the solvent treatment, and the movement of electrons can be made much faster. Because of this ease of movement, electrons can be used as sensing material when exposed to ethanol gas.
3. Signal transducer
The signal transducer is used to convert the change in physical properties of the detection material into an electrical signal that is easy to interpret. The transducer can be designed variously according to the type of gas substance to be detected and the analysis mechanism. In the present invention, a hybrid coupler well known as an RF element can be used to precisely detect minute chemical property changes. The hybrid coupler may operate in the microwave band, i.e., the radio frequency (RF) band. The RF band may range from 3 kHz to 300 GHz, for example.
3 illustrates a modified 4-port 90 degree hybrid coupler usable in the present invention. The hybrid coupler may have a plurality of transmission lines and a plurality of ports formed on a substrate, and may be a four-port 90 degree hybrid coupler preferably having four transmission lines and four ports.
The substrate may be, for example, a printed circuit board (PCB). The substrate may comprise an insulating layer. The size of the substrate is not particularly limited, and can be preferably made small. The size of the substrate may be, for example, 1 mm < 2 > to 100 cm < 2 >
A transmission line may be formed on the substrate and may be in the form of a line having a constant length, width, and thickness. The number of the transmission lines may be plural, preferably four. 3 and 4, the transmission line includes, for example, a first transmission line for connecting the first port (port 1) and the third port (port 3), a transmission line formed substantially in parallel with the first transmission line, A second transmission line connecting the first port (port 2) and the fourth port (port 4), and a third transmission line and a fourth transmission line for vertically connecting the first transmission line and the second transmission line.
The plurality of transmission lines may be made of metal, and one or more transmission lines may include a sensing area formed of conductive polymer on one or more ports. That is, the transmission line may be made of metal such as copper, silver, gold, etc., except for the sensing area. The sensing region may be composed of the conductive polymer as described above. In Fig. 3, the middle rectangular portion can be covered with a mask.
The sensing area may be formed on two adjacent ports of the four ports, and may be formed on the third and fourth ports, for example, as shown in FIGS. 3 and 4. The length of the sensing area is not particularly limited and can be, for example, 1 to 10 mm. The width of the sensing area is not particularly limited and can be, for example, 0.1 to 3 mm. The thickness of the sensing region may be from 0.1 to 30 mu m, preferably from 1 to 20 mu m. If the thickness of the sensing area is too thin, the change due to the gas may be small. If the sensing area is too thick, the introduced gas may be trapped and not be able to escape.
The conductivity of the sensing region (conductive polymer) may be 0.1 to 1 × 10 5 S / m, preferably 0.5 to 1 × 10 5 S / m, more preferably 1 to 1 × 10 5 S / m. If the conductivity of the sensing region is too small, the structure of the coupler may have to be changed due to the proximity of the nonconductor. If the conductivity is too large, the sensitivity of the sensing region may be decreased because the conductivity is decreased.
The sensor shown in Fig. 3 is equivalently shown in Fig. Here, in FIG. 3, the conductive polymer compound located at the
[Equation 1]
Z cp = R cp + jX cp
At this time, when the conductive polymer compound is exposed to the gas, the impedance of the compound changes. Therefore, the changed impedance Z ' cp can be expressed as follows.
&Quot; (2) "
Z ' cp = (R cp + DELTA R) + j (X cp + DELTA X)
In FIG. 4, impedance mismatch occurs between the Z 0 and conductive polymeric compound Z cp or Z ' cp in the 50-ohm transmission line, and the reflection coefficient Γ cp or Γ' cp at that time is obtained as follows.
&Quot; (3) "
&Quot; (4) "
The S-parameter due to the change of the impedance Z cp of the conductive polymer is as follows.
&Quot; (5) "
In Equation (5), R cp ? Z cp is approximated and the equation can be summarized as follows using reflection coefficients.
&Quot; (6) "
The phase shift angle φ between the
&Quot; (7) "
When the polymer compound is exposed to gas, the impedance of the sensor changes. Therefore, the change in amplitude and phase of the signal results in the change.
4. Target gas and sensor characteristics
The target gas of the gas sensor according to the present invention may be at least one selected from Organophosphorus Compound, alcohol (ethanol, etc.), carbon oxide, ammonia, nitrogen oxide, volatile organic compound, oxygen, hydrogen, nitrogen, have.
In particular, DMMP (dimethyl-methyl-phosphonate) among the organic phosphorus compounds is a similar agent of nerve agent sarin, one of the weapons of mass destruction, and has a phosphorus having strong electron affinity. Various methods for detecting DMMP have been studied so far, but it has been difficult to develop a DMMP sensor capable of measuring a room temperature at a very small temperature, because toxicity is very strong and a long time exposure may have a fatal effect. The sensor according to the present invention can be usefully used as a DMMP detection sensor capable of measuring a room temperature at a very small size.
The detection sensitivity of the sensor according to the present invention can be at least 1 ppm based on the concentration of the target gas, and can be at least 10 ppm or more. That is, the sensor according to the present invention is a high sensitivity sensor. The sensor according to the present invention has a high sensitivity by using a hybrid coupler and a conductive polymer. The upper limit of detection sensitivity is not particularly limited, and may be, for example, 1,000,000 ppm, 100,000 ppm, 10,000 ppm, or 1,000 ppm.
The detection temperature of the sensor according to the present invention may be 0 to 40 占 폚. That is, the sensor according to the present invention is detectable at room temperature. The sensor according to the present invention has the advantage that gas can be detected at room temperature by using a hybrid coupler and a conductive polymer.
The detection time of the sensor according to the present invention may be 10 seconds or less, preferably 7 seconds or less, more preferably 5 seconds or less. That is, the sensor according to the present invention has an advantage that the gas can be detected almost in real time by using the hybrid coupler and the conductive polymer.
Further, the sensitivity of the sensor according to the present invention may be 30% or more, the reproducibility may be 5 or more, and the consumed power may be 100 uW or less.
[Example]
A three-port 90 degree hybrid coupler as illustrated in Figures 3 and 4 was fabricated as a gas sensor. A CER-10 PCB substrate with a dielectric constant of 9.7 and a thickness of 0.76 mm from Taconic Inc. was used and the tangent loss was 0.0035. For the high dielectric constant, the total size of the sensor is 20 × 30 ㎟. The sensor was composed of four transmission lines and copper wire was used except for the sensing area. The middle rectangle consisted of a copper wire covered with a mask. The fabricated sensor was operated at 2.4 GHz and the impedance was matched to 50 ohms. The ends of the
PEDOT: PSS solution (Clevios PH 1000, Heraeus) was used as the conductive polymer (CP). The solids content of this solution was 1.1 wt%, and the weight ratio of PEDOT: PSS was 1: 2.5. Also, DMSO (Samseon Pure Chemical Industries) was used.
To optimize the electrical properties of the PEDOT: PSS film, DMSO doping was performed as follows. DMSO was added to the PEDOT: PSS aqueous solution (5.0 v / v%) and gently stirred at room temperature. The solution was then filtered through a syringe filter (0.45 um pore size nylon membrane).
PEDOT: The PSS material is fabricated using a polyimide film to form the material at the correct location. PEDOT: Thin film was formed by spray coating method to improve uniformity of thickness when PSS material was formed on a substrate.
The PEDOT: PSS film on the gas sensor was fabricated as follows. A polyimide tape was applied to the surface as a shield to protect the gold electrode area. The gas sensor substrate is inherently hydrophobic, but the surface can be made temporarily hydrophilic by exposing the surface to an oxygen plasma for improved adhesion. Spray coating treatment of PEDOT: PSS film was carried out by heating at 150 ° C for 1 minute using a hot plate under atmospheric conditions. Because the sprayed PEDOT: PSS liquid droplets dry quickly, a uniform layer could be formed when deposited by spray deposition on a heated substrate.
The electrical conductivity (S / cm) of the PEDOT: PSS film formed on the substrate was measured by a van der Pauw method using a Keithley 2182 nanovoltameter and a Keithley 2400 SMU with a Keithley 7001 switch system ) Were measured in a four-contact configuration. The electrical conductivity was measured to be about 5 × 10 4 S / m. Also, the thickness of the PEDOT: PSS film was measured using an AS-500 alpha-step surface profiler (KLA-Tencor Co., USA), and its thickness was uniformly measured at about 10 μm.
5 shows the results of measurement using an AFM (Demension 3100, Digital Instrument Co.) to observe the surface morphology, and it can be confirmed that a spherical uniform thin film is formed.
The sensor test experiment was conducted by exposing the sensors manufactured in the atmosphere and spraying the sensor with 100 ppm ethanol gas. The carrier gas of ethanol used low-reactivity nitrogen and the exposure level was maintained at 1,000 cc / min through a flow meter to precisely control the injection quantity. The experiment was conducted in a high temperature and humidity environment maintained at a temperature of 28 ° C and a humidity of 85%. For the measurement, a network analyzer (E8364A, manufactured by Agilent) and a jig system (3,680 K, ANRITSU) were used as shown in FIG.
FIG. 7 is a graph showing a comparison between simulation and S-parameter measured in the frequency domain using the manufactured gas sensor. The 90-degree hybrid coupler used was designed to operate in the 2.4 GHz band when all signal lines were metal, but the resonance frequency was measured at 2.3 GHz and about 0.1 GHz away from the design purpose by replacing some of the metal with a conductive polymer material. As a result, it was confirmed that the S 11 value was measured at the lowest value of about -32 dB in the 2.3 GHz band and was similar to the simulation value. In case of S 21 , -2.6 dB was measured in 2.4 GHz band, and loss was higher than simulation.
FIG. 8 shows a phase change of S 21 in the frequency domain according to gas exposure of the manufactured gas sensor. When the gas sensor is exposed to the gas, the phase response to the frequency appears to be shifted to the right as a whole. It was confirmed that Δ (∠S 21 ) was measured at about 9 degrees at 2.4 GHz, and Δf was about 2.875 MHz at -360 degree signal.
9 shows the S 21 value change at 2.4 GHz in the time domain according to the gas exposure of the fabricated gas sensor. The result is that the sensor is repeatedly exposed to 50 ppm and 100 ppm ethanol gas from the gas inlet to the gas outlet. As a result of measurement, the value of Δ | S 21 | was measured at a maximum of 0.13 dB for 100 ppm ethanol gas, and the maximum value of 0.023 dB was measured for 50 ppm ethanol gas. In particular, unlike conventional gas sensor studies, it was confirmed that the graph variation due to gas exposure changes in real time. From the time of gas injection, it was estimated that the sensor takes about 1.5 seconds on average to detect gas. In addition, even when gas is injected several times, the results are similar to each other, and it is confirmed that the repeatability of the gas sensor is excellent.
In Fig. 9, while the ethanol gas is being injected from the gas inflow point to the gas outflow point, the result that the value of? S 21 is slightly shaken is interpreted as due to the high temperature and high humidity environment and the experimental conditions measured in the air, If the experiment through a static vacuum at a relatively low temperature and relative humidity conditions proceeds, more △ | S 21 |, and the value increases, it is supposed that at the same time be measured at a stable level.
As described above, the 90-degree hybrid coupler capable of operating in the 2.4 GHz band is a modified antenna or phase shifter structure in a 4-port hybrid coupler that uses a conductive polymer, PEDOT: PSS, as a sensing material to accurately measure minute amounts of ethanol It is designed so that it can detect and measure quickly with high sensitivity.
Sensitivity is improved by coating a conductive polymer material, which is a sensing material not used in the existing technology, on a transmission line, and it is possible to measure an electrical change such as conductivity, permittivity, impedance and reactance of a conductive polymer according to gas exposure in real time And the time required for adsorption / desorption of gas at room temperature was remarkably reduced to improve returnability.
In addition, since the sensor is easy to fabricate, the application field also varies, and in detecting the organic phosphorus gas, it is possible to speed up the reactivity and reduce the power consumption while correcting the return.
According to the present invention, unlike the conventional static gas detection environment, the gas sensor employing the hybrid coupler type in which the conductive polymer is bonded in the RF band has a high temperature and high humidity condition with a temperature of 28 DEG C and a relative humidity of 85% The measurement was also relatively good.
Claims (13)
Wherein the plurality of transmission lines are made of metal, and at least one transmission line includes a sensing area formed of a conductive polymer on one or more ports,
The hybrid coupler is a four-port 90 degree hybrid coupler with four transmission lines and four ports,
The sensing area is formed on two adjacent ports of the four ports,
The length of the sensing region is 1 to 10 mm, the width is 0.1 to 3 mm, the thickness is 5 to 30 占 퐉,
And the conductivity of the conductive polymer is 0.1 to 1 × 10 5 S / m,
The detection time of the sensor is 5 seconds or less,
The sensitivity of the sensor is not less than 30%, the reproducibility is not less than 5 times, and the power consumption is not more than 100 uW.
Wherein the conductive polymer is at least one selected from pentacene, polyaniline, polypyrrole, polythiophene, and derivatives thereof.
Wherein the conductive polymer is poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate).
Wherein the conductive polymer is doped with dimethyl sulfoxide.
Wherein the sensing region is formed by a spray coating method of a conductive polymer.
Wherein the gas is at least one selected from organic phosphorus compounds, alcohols, carbon oxides, ammonia, nitrogen oxides, volatile organic compounds, oxygen, hydrogen, nitrogen and argon.
Wherein the detection sensitivity of the sensor is 1 ppm or more.
And the detection temperature of the sensor is 0 to 40 占 폚.
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| Title |
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| Byung-Hyun Kim et al., "A Gas Sensor Using Double Split-Ring Resonator Coated With Conducting Polymerat Microwave Frequncies". IEEE SENSORS 2014 Proceedings. pp.1815-1818* |
| J. Fontecha et al., "Fine-tuning of the resonant frequency using a hybrid coupler and fixed components in SAW oscillators for gas detection". SENSORS AND ACTUATORS B. Vol.103 (2004) 139-144* |
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