RU2692832C1 - Passive wireless ultraviolet radiation sensor on surface acoustic waves - Google Patents

Abstract

FIELD: measuring equipment.

SUBSTANCE: invention relates to semiconductor devices for measuring ultraviolet radiation intensity. Sensor comprises housing with piezoelectric acoustic line inside, on ends of which there is sound absorber. On surface of acoustic line there are two transmit-receive interdigitated transducer (IDT) and two reflecting IDT. First transmit-receive IDT and the first reflecting IDT form a measuring channel, the second pair of the IDT is a reference channel. Distance between IDT in measurement channel is more than in reference one. Transmit-receive IDT are connected to antennas, which are half-wave vibrators. Measuring transmit-receive IDT is also connected to impedance. Impedance is an IDT arranged on a dielectric substrate, a photosensitive film is applied on the surface of the IDT, the conductivity of which depends on the intensity of the UV radiation.

EFFECT: high sensitivity and accuracy of measuring UV radiation intensity.

4 cl, 6 dwg, 3 tbl

Description

The invention relates to semiconductor devices for measuring the intensity of ultraviolet radiation, operating according to the principle of comparison with a reference electrical quantity, using piezoelectric transducers on surface acoustic waves.

Sensors for measuring the intensity of ultraviolet radiation are widely used in bactericidal lamps for disinfecting air, in water purification devices, measuring the level of ultraviolet radiation in habitable spacecraft and optical communication devices.

A known ultraviolet radiation sensor based on semiconductor films (RU 2392693, IPC H01L 31/101, publ. 06/20/2010) [1], which contains a silicon substrate, on one of the surfaces of which a titanium electrode is deposited, on the surface of which an aluminum nitride film is applied, on the surface of which is deposited a translucent platinum electrode. When ultraviolet radiation (UV radiation) hits the aluminum nitride film through a translucent electrode, a photo emf appears on the sensor electrodes, or it can operate in the photodiode back-up mode, the resistance of which depends on the power of the UV source. This method of displaying UVBs requires an additional voltage source, even if it works in photo-emf mode, since it is necessary to convert the signal to transmit it over the air or to connect wires to the sensor to read it, which is a disadvantage of this sensor. The sensor has the same drawback (US 9064987, IPC H01L 31/0232, publ. 06/23/2015) [2], in which a zinc oxide film is used as a sensitive layer. In addition, the presence of a translucent electrode leads to some weakening of the UV radiation, which reduces the sensitivity of the sensor. It was suggested in the works (Wenbo Peng, Yongning Nea, Changbao Wen, Ke Ma) to completely get rid of the translucent electrode, as well as directly affect the center frequency of the transmitter generator for radio communication. Sensors and Actuators A 184 (2012) 34-40) [3], (Venkata Chivukula, Daumantas Ciplys, Michael Shur, and Partha Dutta "ZnO nanoparticle surface acoustic wave UV sensor" // APPLIED PHYSICS LETTERS 96, 233512, 2010) [ 4], (Wen-Che Tsai, Hui-ling Kao, Kun-Hsu Liao, Yu-Hao Liu, Tzu-Ping Lin, and Erik S. Jeng "SAW UV photodetector with small temperature coefficient "// OPTICS EXPRESS, 9 Feb 2015 Vol. 23, No. 3, 2187) [5], (Sanjeev Kumar, Gil-Ho Kim, K. Sreenivas, RP" Tand on ZnO based surfac e. acoustic wave ultraviolet photo sensor "// J. Electroceram (2009) 22, p. 198-202) [6], (Wang Wen-Bo, Gu Hang, He Xing-Li, Xuan Wei-Peng, Chen Jin-Kai , Wang Xiao-Zhi, and Luo Ji-Kui, "Transparent Zeno / glass Surface Sensors", // Chin. Phys. In Vol. 24, No. 5 (2015) 057701) [7], (US 7989851, IPC H01L 29/82, published 02.08.2011) [8], (US 6914279, IPC H01L 29/82, published 07.05.2005) [9], (US 6621192, IPC H01L 41/08, published September 16, 2003) [10]. A sensor containing a piezo-substrate, on the working surface of which in one acoustic channel are located receiving and transmitting interdigital transducers and a film sensitive to ultraviolet radiation signals, between them [3, 4, 5] and acoustic absorber on the ends of the substrate. This allows the transmitter center frequency to measure the intensity of the UV radiation without any other signal converting circuits, which will simplify the design of UV radiation sensors and increase their reliability. The principle of operation of these sensors is based on the change in attenuation and velocity of surface acoustic waves (SAW) on the intensity of UV radiation due to the acoustoelectronic interaction of surfactants with conduction electrons in the semiconductor layer located on the surface of the piezoelectric substrate, along which the surfactants propagate. The concentration of electrons, in turn, depends on the intensity of the UV rays, which makes it possible to judge the presence and intensity of UV rays. Since the acoustoelectronic interaction changes the surfactant velocity, this leads to a change in the center frequency of the interdigital transducer [6, 7], if the interdigital transducers (IDT) are deposited on a zinc oxide film, which also has piezoelectric properties or a generation frequency shift [ 3, 4, 5, 8, 9, 10], if the film sensitive to UV radiation is between the receiving and transmitting IDT in the SAW resonator. Since the rate of the surfactant depends on the temperature, the central frequency of IDT or the frequency of the resonator will depend on the temperature, which must be taken into account when measuring the UVR. But this is not easy to do, because the acoustoelectronic interaction depends on the square of the electromechanical coupling coefficient, which is very small for thermally stable sections of quartz, which leads to a weak dependence of the surfactant velocity, and hence the frequency, on the intensity of UVR. In lithium niobate substrates, the square of the electromechanical coupling coefficient is 30 times greater, but in it the rate of surfactant depends on temperature much more than in quartz.

This disadvantage is eliminated in the sensor of physical quantities (RU 2613590, IPC-2006.01 H01L 31/101, Н03Н 9/25, publ. 03/17/2017) [11], containing a piezoelectric substrate, on the working surface of which there is a transmitter and receiver in one acoustic channel unidirectional IDT and two reflective IDT, and between reflective IDT at a distance of no more than the SAW length at the center frequency of the IDT, a UV-sensitive semiconductor zinc oxide film deposited on a dielectric substrate that is transparent to the UVI, which lies n supports located on either side of the acoustic channel at the edges between the reflective pezopodlozhki IDT, and a transmit-receive IDT connected transceiver antenna.

In this design, the signals reflected from IDT before and after passing through the area under the film will differ significantly when exposed to UVR. In this case, changing the speed of the surfactant will not affect the amplitude of the reflected pulses, and, consequently, affect the accuracy of measuring the intensity of UV radiation. However, this design has a significant drawback due to the presence of a transparent window in the housing for UVBs, which complicates the design and reliability of the housing. This is due to the fact that in the microwave range, in which it is preferable to work with wireless passive sensors with miniature antennas, the housing must be sealed so that dirt and dust do not get into the acoustic path, since the microwave attenuation of the surfactant strongly depends on its pollution.

To eliminate these drawbacks allows the sensor (RU 2387051, IPC H01L 41/107, G01D 5/12 (2006.01), publ. 04/20/2010) [12], which is the closest analogue to the claimed invention by purpose, performance and the achieved result and is adopted prototype.

The sensor prototype contains a sealed enclosure inside which there is a piezoelectric acoustic conduit, on the working surface of which, in a single acoustic channel, there is a reflective and transceiver counter-whip transducer loaded onto the antenna through the terminals in the enclosure that is located outside the sealed enclosure, and reflective IDTs located on both sides of the receiving and transmitting IDT, with one of the reflective IDT connected to the impedance, the value of which is sensitive to temperature, pressure, wet ti, ionizing radiation, electromagnetic radiation, including and UVB, and forms together with the GSW transceiver measuring channel, the other reflective IDTs forms with the transceiver IDT reference channel. In this case, in the measuring channel, the reflection coefficient of the surfactant from reflective IDT depends on the magnitude of the impedance, the magnitude of which depends on the measured physical quantity, but not in the reference channel. Since the case is sealed, the IDT and the substrate are isolated from the environment, which increases the reliability of the sensor. The sensor is polled using a reader, sending a polling electromagnetic pulse, which is received by the sensor antenna and converted into surface acoustic waves (SAW), which are reflected from the reflective IDT, are received by the transceiver and IDT, and again converted into an electromagnetic signal, which is received by the receiver of the reader. The magnitude of this signal obviously depends on the reflection coefficient, which, in turn, depends on the magnitude of the impedance loaded on the reflective IDT in the measuring channel. This impedance, in turn, depends on the measured physical quantity, for example, the intensity of the UV radiation. In the reference channel, the magnitude of the signal due to the reflection of the surfactant from reflective IDT does not depend on the measured physical quantity. Then comparing the pulses reflected from the reference and measuring channel, determine the measured physical quantity.

However, with weak changes in the reflection coefficient, due to a change in intensity, the ratio of the amplitudes of the pulses received by the reader will change very little, making it impossible to determine the intensity of the UVR in a real disturbing environment and leads to a decrease in the sensitivity and accuracy of the UVI intensity measurement. In the prototype, under the action of electromagnetic waves, the reflection coefficient of the surfactant from reflective IDT changes, therefore the reflection coefficient of electromagnetic waves from the antenna is determined only by the reflection coefficient of the surfactant from reflective IDT.

The problem to which the invention is directed, is to create a wireless UVI devoid of these shortcomings.

The task is solved due to the achievement of a new technical result - increasing the sensitivity and accuracy of measuring the intensity of UVBs by changing the impedance matching of the ACP IDP with the impedance of the antenna connected to it depending on the frequency of the readout signal, which leads to an increase in the irregularity of the frequency response, and as a result, an increase in amplitude pulse of the inverse Fourier transform.

This technical result is achieved by the fact that the passive wireless sensor of ultraviolet radiation on surface acoustic waves contains a sealed housing, inside which is located a piezoelectric acoustic duct, on the working surface of which in one acoustic channel are located transceiver interdigitated transducer (IDT) connected antenna, the first unidirectional reflective IDT, which forms a measuring channel with external transceiver IDT, external impedance, led rank which is sensitive to the measured value of the intensity CFIs, and a second unidirectional reflective IDTs, which forms with the transceiver IDT perch channel akustopoglotitel supported on the ends of the acoustic line.

According to the invention, the external impedance contains an interdigital structure located on a dielectric substrate, made in the form of two comb-shaped electrodes nested into each other, on the surface of which a photosensitive film is applied, the conductivity of which depends on the intensity of the UV radiation, and the comb-shaped electrodes are connected to the receptacles -transmitting unidirectional IDT, which, together with one of the reflective unidirectional IDTs, forms the measuring channel, in parallel with which the reference acoustic is input A common channel containing reflective unidirectional transducer and unidirectional transceiver transducer connected via terminals in the housing with the antenna, both antennas are made in the form of half-wave vibrators located on the same straight line, and the distance between transducer in the reference acoustic channel is less than the distance between transducer in the measuring acoustic channel, at least the length of the reflective IDT. In preferred embodiments, execution:

- the period of comb electrodes is equal to the period of IDT;

- dielectric substrate is made of a piezoelectric material;

- photosensitive film made of zinc oxide.

Increasing the sensitivity and accuracy of UV intensity measurements is due to the fact that the external impedance, the magnitude of which depends on the intensity of the UV radiation is connected in the measuring channel to the transceiver, and not to reflective IDT.

The invention is illustrated by the figures of the drawings, where:

FIG. 1. Passive wireless sensor of ultraviolet radiation on surface acoustic waves, general view.

FIG. 2. Frequency dependences of the parameter S ₁₁ , where curve 1 is the frequency dependence of the parameter S _{11 of the} measuring channel in the presence of a PFI, curve 2 is the frequency dependence of the parameter S _{11 of the} measuring channel in the absence of a PFI.

FIG. 3. The time dependence of the parameter S ₁₁ , where curve 1 is the Fourier transform amplitude of the frequency dependence of the parameter S ₁₁ in the presence of UVI, curve 2 is the Fourier transform amplitude of the frequency dependence of the parameter S ₁₁ in the absence of UVI, where curve 3 is the Fourier transform amplitude of frequency dependences of the parameter S ₁₁ in the reference channel.

FIG. 4. The time dependence of the parameter S ₁₁ , where curve 1 is the Fourier transform amplitude of the frequency dependence of the parameter S ₁₁ in the presence of UVI, curve 2 is the Fourier transform amplitude of the frequency dependence of the parameter S ₁₁ in the absence of UVR, curve 3 is the Fourier transform amplitude of the frequency dependences of the parameter S ₁₁ in the reference channel.

FIG. 5 The time dependence of the parameter S ₁₁ , where curve 1 is the Fourier transform amplitude of the frequency dependence of the parameter S ₁₁ in the presence of UFI, curve 2 is the Fourier transform amplitude of the frequency dependence of the parameter S ₁₁ in the absence of UFI, where curve 3 is the Fourier transform amplitude of the frequency dependence parameter S ₁₁ in the reference channel.

FIG. 6 The dependence of the Fourier transform amplitude on the intensity of the UV radiation of the inventive passive wireless sensor of ultraviolet radiation on surface acoustic waves, where curve 1 is the impedance performed on a piezoelectric substrate, curve 2 is the impedance made on a dielectric substrate.

A passive wireless ultraviolet radiation sensor on surface acoustic waves (Fig. 1) contains a sealed housing 1, inside which is located a piezoelectric transducer 2, on the working surface of which in one acoustic channel are located transceiver interdigitated transducer (IDT) 3 connected via pins 4 in housing to the antenna 5, the first unidirectional reflective IDT 6, which forms a measuring acoustic channel with the transmitting IDT 3. Acousto-absorbers 7 are applied on the ends of the piezoelectric Zvukovaya 2. The interdigital structure of VShS 8 is made in the form of two comb-shaped electrodes nested in each other located on a dielectric substrate 9, a photosensitive film 10 is applied on the surface of VShS 8, the conductivity of which depends on the intensity of the UFI, comb-shaped electrodes through the terminals in the housing are connected to the transceiver unidirectional IDT 3; Parallel to the measuring instrument, a reference acoustic channel is inserted, containing a reflective unidirectional WB 11 and the receiving-transmitting unidirectional IDT 12 connected through terminals in the housing with an antenna 13. Antennas 5 and 13 are in the form of half-wave dipoles disposed on one straight line.

When applying to the receiving-transmitting antenna 5 of the reading electromagnetic pulse from the interrogator, the latter transforms into the SPT 3 into a SAW pulse, which is reflected from the reflective IDT 6. The IDT 3 and IDT 6 are made unidirectional (RU 2195069 IPC H03H 9/145 publ. 2002.12. 20) [13], so that the surfactants are emitted (received), mainly towards the (from the side) reflective IDP 4, which will reduce the attenuation of the electromagnetic pulses reflected from the sensor, since the emission of the surfactant in the opposite direction (towards the surfactant absorber) 10 times smaller Than toward the reflective IDTs 3, which reduces the loss of electromagnetic pulse energy conversion in the SAW propagating in the direction of the reflective IDTs. So that surfactants emitted to the ends do not distort the sensor operation (they did not lead to spurious impulses), an acousto-absorber 7 was applied at the end of the piezoelectric acoustic duct, which absorbs the surfactant and prevents them from falling back into the IDT 3. The SAW pulses reflected from the reflective IDT are returned to the receiving-transmitting IDT. There they are converted into an electrical signal, which induces an electromagnetic pulse in the antenna, which is radiated back to the interrogator.

Since the reader can be located at different distances when interrogating the sensor or the propagation conditions of electromagnetic waves (rain, fog) can change, the amplitude of the pulse reflected from the sensor will depend on the propagation conditions and the distance between the reader and the sensor. To prevent this from happening, a reference acoustic channel is introduced parallel to the measuring channel, consisting of a receiving and transmitting IDT 11. The reflecting IDT 13 is also in the same channel. IDT 12 is connected to the receiving and transmitting antenna 13, the half-wave vibrators of which are in one straight line with half-wave vibrators in the antenna 6 connected to the transceiver IDT 3 connected to the impedance (Fig. 1). In this case, there is almost no connection between the antennas, since they emit electromagnetic waves perpendicular to the half-wave vibrators. Since the IDT 3 and IDT 6 are located in the measuring channel, we can assume that the measuring and reference channels are not interconnected and will not affect each other. In the reference channel, the distance between IDT 11 and IDT 12 is selected smaller by IDT 3 along the SAW propagation direction than the distance between IDP 3 and 4. Therefore, the reflection peak from the reference channel appears earlier than the reflection peak from the measuring channel. FIG. 3, it can be seen that the peak of reflection from the reference channel 3 appears earlier than the peak of reflection from the measuring channel; these peaks are separated in time and can be easily identified and compared. When the propagation conditions of electromagnetic waves between the sensor and the reader change, the reflected signals may change, but their ratio will not depend on these conditions, since the peaks of reflection from the reference and measuring channels will also change at the same time.

The magnitude of the impedance consisting of a VSH 8 with a photosensitive film 9 deposited on it, which are located on the substrate 10, changes its value under the action of the UVR. This not only leads to a change in the reflection coefficient of the surfactant from the IDT, but also the degree of its coordination with antenna 6. It is obvious that at some frequencies in this case the degree of matching increases, and at some frequencies it decreases, which leads to an increase in the range of oscillations at the frequency dependence parameter S ₁₁ (the ratio of the electromagnetic wave reflected from the sensor antenna to the incident one, see Fig. 2), and, consequently, to an increase in the reflection coefficient of the electromagnetic signal from the sensor. In this case, in contrast to connecting impedance to reflective IDT, the effect of a change in impedance on the reflection coefficient of the electromagnetic signal from the sensor will increase. From FIG. 3 it can be seen that when external impedance is connected to the transceiver transceiver, the impulse response value changes 2.05 times (the ratio of the area of curve 1 to the area of curve 3) under the influence of UVR, and when external impedance is connected to reflective transducer, as can be seen from FIG. 4, this ratio (the ratio of the area of curve 2 to the area of curve 3) under the influence of UVB changes only 1.46 times. Moreover, in this case, with an increase in the intensity of the UVI, the amplitude of the reflected pulses falls, unlike in the case when the impedance is connected to the receiving and transmitting IDT 3, where the amplitude of the reflected pulses increases with the intensity of the UVI.

The HSG 8 period is equal to the period of the IDT 3 and IDP 4, and the substrate 10 is made of the same piezoelectric material as the piezoelectric sound conduit 1, then the influence of external impedance may increase due to the fact that HShS 8 acquires additional active impedance due to the emission of a surfactant. In this case, the photosensitive film will, upon irradiation of the UVR, affect the magnitude of the reflection coefficient, as well as the degree of matching of the transceiver of the IDT with antenna 6, since the impedance value will be close to the radiation resistance of the IDT 3 and IDT 4 already without the presence of the UFI IDT 12. The presence of a PFI will only lead to a greater mismatch of the impedance of the IDT with the antenna. If the GSM 8 period is different from the IDT 3 and the IDT 4 or the substrate is not piezoelectric, which is equivalent, then the effect on the reflectance of electromagnetic waves from the sensor will be less, as shown in FIG. 5. It can be seen that the ratio of peak 1 reflection in the presence of UVRs differs from peak reflection 3 by 1.6 times, which is less compared to the same ratio when the period of HSS 8 is comparable to the period of IDT 3 and IDT 4 12. The fact is that in the case of a difference between the period of the VShS 8 and the period of the IDT 3, the VShS 8 is a capacitance, and the resistance in the impedance is caused only by the presence of a photosensitive film. The same can be said if the VSW is located on a dielectric (not piezoelectric) substrate.

When external impedance is connected to the transceiver IDT 4, it may seem that the reflective IDT becomes unnecessary, since the impedance affects the reflection coefficient without it, but without reflective IDT 4 the electromagnetic signal reflected from the sensor antenna will come almost at one and the same same time as signals reflected from surfaces near the sensor. In this case, it will be impossible to separate these signals and measure the intensity of the UV radiation. In the presence of reflective IDP 4, the signal reflected from it will come a few microseconds later, because the SAW speed is five orders of magnitude lower than the speed of electromagnetic waves, and the distance between the IDT can be 6-20 mm. This corresponds to the reflection of an electromagnetic signal from surfaces located at a distance of 600-1200 m from the sensor. In this case, the magnitude of the signals reflected from the surfaces will be greatly weakened. At the same time, the signal caused by the reflection of surfactant from reflective IDT will be much larger and will be easily identified. Thus, without the presence of reflective IDT 6, the sensor will be inoperative.

To assess the increase in the accuracy of the claimed sensors, measurements were made of the intensity of UV radiation with the help of the Obzid-304 impedance analyzer. This device measured the frequency dependence of the parameter S ₁₁ transceiver IDT. Next, the Fourier transform of the measured frequency response was performed and the impulse response of the sensor was obtained. The VShS was connected to the delay line using a 20 cm long compact coaxial cable, and the VShS itself was fixed on the optical bench and the UV radiation from a helium-cadmium laser (325 nm) was fed through the hole in the metal plate. Moreover, the laser beam was focused to a diameter of 1.5 mm at a distance of 12.3 cm from the lens. Next, the VSW was removed from the lens. At the same time, the beam diameter became larger, but at the VShS it remained unchanged due to the fact that a metal plate with a hole of 1.5 mm in diameter was directly in front of it. Due to the fact that the beam diameter increased, the intensity of the UV rays decreased with increasing distance to the lens. This allowed to change the intensity of the UV radiation from 1312 mW / cm ² to 35.6 mW / cm ² . Thus, it was possible to measure the dependence of the surfactant reflection coefficient on the reflective IDT, if the HS was connected to it, and the dependence of the transfer coefficient on the receive-transmit IDT, if the HS was connected to it, on the intensity of the UVR.

Unidirectional IDT 3, 4, and 11, 12 contained 18 active and reflective sections. The aperture of the IDT was chosen to be 1.72 mm, and the distance between the IDT in the measuring channel was 18.7 mm, and in the reference channel - 12 mm. The IDTs were located on a piezoelectric YX / 127 ° sound line - a cut of lithium niobate.

FIG. 2 shows the frequency dependence of the parameter S ₁₁ VSHS when the film is connected to the transceiver transmitting IDT and stored, or when no UVB (curve 2) or under the effect of UVB maximum intensity equal to 1312 mW / cm ² (curve 1). FIG. 3 shows the impulse response of the sensor, representing the Fourier transform of the above frequency dependencies. In this case, the external impedance is a VSH 8 with the same period as the IDT 3 and 4, on which a photosensitive film of zinc oxide with a thickness of 200 nm is applied. HS 8 with a film 9 are located on a piezoelectric substrate of lithium niobate YX / 127 ° - cut, i.e. the substrate is the same as the piezoelectric transducer 2 sensor.

To compare the pulse areas, in the absence of a UVI (curve 1) and with a UVI (curve 2), we took the ratio of the pulse areas without UVI, which are equal to the pulse areas in the reference acoustic channel, to the pulse areas at UVI, respectively. In this case, the areas of the pulses in the absence of CFIs (q ₀ ) were equal to the area of the pulses reflected in the reference acoustic channel (q _reference ). The areas were defined as integrals over time, starting from the point in time where the corresponding reflection peak is still close to zero (no more than 0.01) and ending with the time point where the reflection peak is already close to zero (no more than 0.01).

Table 1 shows the calculations of the areas of reflection peaks when the external impedance is connected to the transceiver.

From table 1 it can be seen that with increasing UVI intensity, the reflection coefficient of the electromagnetic signal from the sensor increases and takes the maximum value equal to q1 ₀ / q1 ₈ = 2.05 when the radiation intensity is 1312 mW / cm ² .

Table 2 shows the changes in the reflection coefficient from the sensor when the external impedance is connected to reflective IDT (see Fig. 4, curves 1 and 2)

From Table 2 it can be seen that with increasing UVI intensity, the reflection coefficient of the surfactant from the IDT 4 decreases and the maximum change is 1/0696 = 1.464, which is less than in the case of connecting external impedance to the receiving-transmitting IDT 3.

Table 3 shows the dependence of the reflection coefficient from the sensor when the external impedance connected to the transceiver transceiver is located on the piezoelectric substrate, but the HSG 8 period differs from the IDT period, so that its operating frequencies as the IDT are lower by 6 MHz, than the VSP 3 and 4 sensors. Then a VSW without a film can be considered as the capacitance and the piezoelectric properties of the substrate no longer matter.

From table 3 it can be seen that with increasing UVI intensity, the reflection coefficient of the electromagnetic signal from the sensor increases as in the first case.

FIG. 6 shows the calibration curves for the sensor, in which the external impedance with VShS 8, having a period equal to the period of the IDT 3 and 4 (curve 1), as well as for the sensor, when the HSV has a period different from the period of the IDT (curve 2). These curves represent the ratio of the amplitude of the primary reflected pulse without UVR to the amplitude of the same pulse at different UVI intensities. It can be seen that in the first case, the calibration curve depends more strongly on the radiation intensity at low UV radiation intensities. Knowing this relationship, it is possible to determine the intensity value of the UV radiation from this curve. For example, if the ratio q1 _i / q1 ₀ = 1.71, the intensity of the UV radiation is 140 mW / cm ² (dotted lines in Fig. 6).

Information sources:

1. RU 2392693, IPC H01L 31/101, publ. 06/20/2010

2. US 9064987, IPC-2014.01, H01L 31/0232, publ. 06.23.2015

3. Wenbo Peng, Yongning Nea, Changbao Wen, Ke Ma, "Sensors and Actuators A 184 (2012) 34-40

4. Venkata Chivukula, Daumantas Ciplys, Michael Shur, and Partha Dutta "ZnO nanoparticle surface acoustic wave UV sensor" // APPLIED PHYSICS LETTERS 96, 233512, 2010

5. Wen-Che Tsai, * Hui-ling Kao, Kun-Hsu Liao, Yu-Hao Liu, Tzu-Ping Lin, and Erik S. Jeng "SAW UV" photodetector with small temperature coefficient "// OPTICS EXPRESS, 9 Feb 2015 Vol. 23, No. 3.2187.

6. Sanjeev Kumar, Gil-Ho Kim, K. Sreenivas, R. P. "Tand on ZnO-based surface acoustic wave ultraviolet photo sensor" // J Electroceram (2009) 22, p. 198-202.

7. Wang Wen-Bo, Gu Hang, He Xing-Li, Xuan Wei-Peng, Chen Jin-Kai, Wang Xiao-Zhi, and Luo Ji-Kui "Transparent ZnO / glass surface acoustic wave based high-performance ultraviolet light sensors" // Chin. Phys. In Vol. 24, No. 5 (2015) 057701.

8. US 7989851, IPC-2006.01 H01L 29/82, publ. 08/02/2011.

9. US 6914279, IPC-2006.01 H01L 29/82, publ. 05/07/2005.

10. US 621192, IPC ⁷ H01L 41/08, publ. September 16, 2003.

11. RU 2613590, MPK-2006.01 H01L 31/101, H03H 9/25, publ. 03/17/2017.

12. RU 2387051, IPC H01L 41/107, G01D 5/12 (2006.01), published 04/20/2010 - a prototype.

13. RU 2195069, 7MPK H03H 9/145, publ. 12.20.2002.

Claims (4)

1. Passive wireless ultraviolet radiation sensor on surface acoustic waves, containing a sealed enclosure, inside which is located a piezoelectric acoustic conductor, on the working surface of which, in one acoustic channel, there is a transceiver transmitting interdigital transducer (IDT) connected through the terminals in the housing to the antenna, the first unidirectional reflective IDT, forming with the transceiver IDT measuring channel, external impedance, the value of which is sensitive to the measured intensity ultraviolet radiation (UV), and the second reflective unidirectional IDT, which forms a supporting channel with the transmitting and receiving IDT, acousto-absorber deposited on the ends of the acoustic duct, characterized in that the external impedance contains an interdigital structure located on the dielectric substrate, made in the form two comb electrodes nested into each other, on the surface of which a photosensitive film is applied, the conductivity of which depends on the intensity of UV radiation, the comb electrodes through the terminals in the bus is connected to the first transceiver unidirectional transducer, which, together with one of the reflective unidirectional transducer, forms a measuring channel, parallel to which a reference acoustic channel is inserted, containing the second reflective unidirectional transducer and the second unidirectional transceiver transceiver, connected via the terminals in the housing to the antenna, both antennas are made in the form of half-wave vibrators located on one straight line, and the distance between the IDT in the reference acoustic channel is less than the distance between IDT in an acoustic measuring channel, at least for the length of reflective IDTs. 2. Passive wireless sensor according to Claim. 1, characterized in that the period of the comb electrodes is equal to the period of the IDT. 3. Passive wireless sensor according to Claim. 1, characterized in that the dielectric substrate is made of a piezoelectric material. 4. Passive wireless sensor according to Claim. 1, characterized in that the photosensitive film is made of zinc oxide.

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