KR101828219B1 - Tag for detecting a sink hole - Google Patents

Abstract

The present invention relates to a tag embedded in a certain depth of a ground, which can be recognized through a reader moving at a predetermined height on the ground, minimizing signal distortion in an underground environment, facilitating conjugate matching according to various dielectric properties of a buried soil medium The present invention relates to a tag that can be recognized by a reader that is buried in the ground and moves on the ground, An antenna that transmits and receives signals to and from the reader by the tagging of the reader according to the tagging of the reader; A body portion to which the antenna is attached; A base plate formed in a plate shape and supporting the body portion; A lid part which is formed in a tubular shape and accommodates the body part and engages with the bottom plate part; And a control unit.

Description

TAG FOR DETECTING A SINK HOLE}

More particularly, the present invention relates to a tag embedded in a certain depth of a ground, which can be recognized through a reader moving at a predetermined height on the ground, minimizing signal distortion in an underground environment The present invention relates to a tag for detecting a ground recess which can easily optimize the conjugate matching according to various dielectric constant characteristics of the buried soil medium and thus shows accurate cognitive performance irrespective of the type of the soil medium buried.

The development of the urban area has caused the depression of the downtown area frequently due to the development of the elevation, and the sensitivity to safety has increased. The ground depression of the pavement seems to occur suddenly, but it is due to the cavitation phenomenon occurring in the ground for a long time, so it is necessary to observe it periodically.

One of the ways to identify underground cavitation phenomenon is to use Ground Penetration Radar. This method provides a considerable degree of image of the structure of the underground environment and may be effective for the precise analysis of a specific area due to its technical characteristics, but it is inappropriate as a periodical monitoring means for a wide area. In addition, the technique of monitoring an underground condition by embedded an active detection sensor including an acceleration sensor or a humidity sensor is technically effective, but the sensor cost per surveillance area is so high that it is not preferable to be used for detection in a wide area.

The RFID tag is used as a sensor embedded in the ground and it is economical because the unit price of buried tag is comparatively low. Among the RFID tags, the passive RFID tag of the UHF band is excellent in recognition speed and relatively inexpensive because it is suitable for effective monitoring of a large area. As described above, the technique of detecting the ground subsidence under the RFID-based package is well disclosed in the applicant's patent (Patent Application No. 2016-0076599).

The RFID (passive) system consists of a tag and a reader, and provides an application service linked to the Internet through a host. When the tagged object is placed in the reader's recognition range, the reader sends an interrogation to the tag, and the tag responds to the reader's query. The reader modulates a continuous electromagnetic wave having a specific frequency to transmit a question signal to the tag, and the tag transmits the electromagnetic wave transmitted from the reader to transmit its information stored in the internal memory to the reader. The back scattering modulation is an electromagnetic wave When the tag is scattered and sent back to the reader, the tag information is transmitted by changing the magnitude and phase of the scattered electromagnetic wave.

The passive tag does not oscillate by itself, but rectifies the electromagnetic wave sent from the reader to obtain the operating power and uses it as its power source. Therefore, the recognition range of the tag is limited by the strength of the radio wave transmitted from the reader and reaching the tag.

The passive RFID tag rectifies the electromagnetic wave sent from the reader and uses it as its own power source. In order for the tag to operate normally, the intensity of the radio wave transmitted to the tag must be above a certain threshold. Also, if the intensity of the radio wave does not reach a certain threshold value, the recognition area is limited. It is impossible to increase the power indefinitely by the radio laws of each country. Since the intensity of the radio wave is limited in the reader, the tag must efficiently receive the radio wave received from the reader.

In order to increase the reception efficiency of the RFID tag, an antenna having a conjugate value of the resistance value and the capacitor value of the chip is required. If mismatching occurs, the maximum efficiency is not achieved, resulting in a reduced recognition distance. The addition of an inductor and a passive passive element to achieve matching in addition to the antenna is undesirable because of an increase in price. Therefore, the antenna should be matched with the chip using only the antenna.

The ground to which the bottom ground penetration detection technique is applied in the actual RFID-based pavement is composed of the pavement composition ground of the new road or urban railway section, the pavement of the replacement section of the water and sewage pipe, . If the tags are embedded in these grounds, the characteristics of the soil medium wrapped in the tags are slightly different. Therefore, it is necessary to match the tag matching according to the characteristics of the soil medium. However, at present, there has not been developed a dedicated tag for detecting the ground subsidence under the RFID-based package which can be recognized accurately by a reader which is buried at a certain depth of the ground and moves quickly at a certain height of the ground.

In addition, since the permittivity of the medium differs depending on the characteristics of the soil medium in the applied area, the conjugate matching of the tag should be slightly different for each application region. In the current tag antenna structure for public use, it is difficult to meet the conjugate matching according to various dielectric properties of the soil medium As a result, it is necessary to match the conjugate matching of the tag antenna for laying uniformly, so that there is a difference in the recognition performance of the tag according to the applied ground, which causes the reliability of the exploration data to deteriorate.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and its object is to provide a tag embedded in a certain depth of a ground, which can be recognized through a reader moving at a predetermined height on the ground, The purpose of this paper is to provide a tag for detection of ground cavities.

Particularly, it is another object of the present invention to provide a tag for detecting the ground penetration, which can easily optimize the conjugate matching according to various permittivity characteristics of the buried soil medium, thereby showing accurate cognitive performance irrespective of the type of soil medium buried therein .

According to the present invention, there is provided an RFID tag embedded in the ground and recognizable through a reader moving on the ground, the antenna transmitting and receiving signals to and from the reader through the ground in accordance with the tagging of the reader; A body portion to which the antenna is attached; A base plate formed in a plate shape and supporting the body portion; A lid part which is formed in a tubular shape and accommodates the body part and engages with the bottom plate part; The tag for detecting the ground penetration is provided.

Preferably, the antenna is formed in a dumbbell shape in which a circular first radiation patch and a second radiation patch are connected at both ends around a connection patch in an unfolded state, and when the connection patch is attached to the body, The first radiation patch and the second radiation patch are folded at the same angle in the same direction to form a folded shape of a C-shaped structure.

Preferably, the antenna in the unfolded state is formed with a dual slot matching portion in the form of a straight line horizontal along the longitudinal direction in which the first radiation patch, the connection patch and the second radiation patch are arranged in a row, and the dual slot matching portion is parallel Wherein each of the slots is formed to extend from a left edge position of the connection patch to a right edge position of the second radiation patch and a length of the dual slot matching portion is set to a second radiation patch And the chip and the antenna are matched with each other according to the dielectric constant of the soil medium in which the tag is buried.

Preferably, the antenna in the unfolded state is formed with a linear line-shaped stub-matching portion along the longitudinal direction in which the first radiation patch, the connection patch and the second radiation patch are arranged in a row, and the stub- Wherein each of the slots is formed by extending to the right edge of the second radiation patch at a point where the side face and the bottom face of the connection patch meet the second radiation patch, And the length is extended horizontally toward the outer side of the second radiation patch to match the chip and the antenna according to the permittivity of the soil medium in which the tag is embedded.

Preferably, the antenna in the unfolded state is formed with an electric field direction matching portion in the form of a meander line in a direction perpendicular to the longitudinal direction in which the first radiation patch, the connection patch and the second radiation patch are arranged in a row, Slots formed in the dual slot matching portion of the patch in a direction perpendicular to the longitudinal direction in which the dual slot matching portion is formed and each slot is formed in a vertical direction in each slot of the dual slot matching portion And the length of the horizontal line extending from the last bent portion of the field direction matching portion is extended horizontally toward the outer side of the second radiation patch so that the length of the soil in which the tag is embedded And the chip and the antenna are matched according to the permittivity of each medium.

Preferably, the unfolded antenna is formed with a dual-slot GND matching portion in the form of a straight line horizontal along the longitudinal direction in which the first radiation patch, the connection patch and the second radiation patch are arranged in a row, and the dual- Wherein the dual patch comprises two long slots formed in parallel to each other and having a straight line shape in a direction opposite to the formation direction of the dual slot matching portion at a point where the dual slot matching portion and the field direction matching portion meet in the connection patch, The length of the slot GND matching portion is extended and changed to the first radiation patch direction to match the chip and the antenna according to the permittivity of the soil medium in which the tag is buried.

Preferably, the bottom plate is formed with a receiving groove capable of receiving a magnetic body at the center of the upper side, and the magnetic body accommodated in the receiving groove is provided with a magnetic force detector through which the magnetic force is detected, So that it is possible to judge whether or not it is possible.

Preferably, the body portion is disposed on the bottom plate portion and is covered by the lid portion to be received therein. The body portion is provided with an attachment plate to which the antenna can be attached, The patch is vertically attached, the second radiation patch is attached horizontally on the upper surface of the attachment plate, and the first radiation patch is horizontally attached to the lower surface of the attachment plate so that the antenna has a folded shape of the C shape .

Preferably, the inner side surface of the lid part is provided with a fitting protrusion, and the fitting protrusion is fitted into the fitting groove formed on the side of the body part, so that the lid part and the bottom plate part are engaged. On the outer side surface of the lid part, The coupling groove is formed at a position corresponding to the coupling protrusion of the base plate and the coupling groove is inserted into the coupling protrusion so that the coupling between the cover and the bottom plate is assisted and the coupling portion between the bottom plate and the cover is subjected to ultrasonic welding.

According to the present invention, a tag embedded in a certain depth of the ground can be recognized through a reader moving at a predetermined height on the ground, and signal distortion in an underground environment can be minimized.

In particular, the conjugate matching can be easily optimized according to the various permittivity characteristics of the buried soil medium, so that accurate cognitive performance is exhibited irrespective of the kind of the buried soil medium.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view of an antenna of a tag for ground penetration detection according to an embodiment of the present invention; FIG.
FIG. 2 is a view illustrating a state in which an antenna of a tag is folded to detect ground penetration according to an embodiment of the present invention. FIG.
FIG. 3 is an exploded view of a package of a tag for detecting ground penetration according to an embodiment of the present invention. FIG.
4 is a package assembly diagram of a tag for detecting ground penetration according to an embodiment of the present invention.
FIGS. 5 to 10 are diagrams for explaining an impedance matching matching test procedure for a tag antenna for detecting ground penetration according to an embodiment of the present invention. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that the same components or parts among the drawings denote the same reference numerals whenever possible. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as not to obscure the subject matter of the present invention.

The present invention provides a system for quickly detecting a ground surface depression, comprising: a tag embedded in a lower portion of a package installed on the ground; a sensing means for recognizing the tag on the ground; A sensing unit, a moving unit for moving the sensing unit and the sensing unit on a package, and a server for providing position information for each tag to the sensing unit, And may be configured to include an antenna and a reader. The rapid detection system for ground penetration in this configuration is well described in the applicant's patent (Patent Application No. 2016-0076599), so that a detailed description thereof will be omitted.

In the geotechnical indentation rapid detection system according to the present invention, RFID (Radio Frequency Identification) tag technology, which is one of contactless type object recognition techniques, is used.

In the present invention, the basic concept of the technology for detecting the ground depression using the RFID technology is as follows. The tag embedded in the specific depth below the package can communicate with the mobile antenna on the top of the package before the ground depression occurs, and the tag information can be transmitted to the reader. However, If the distance exceeds the communication distance, the communication with the antenna on the upper side of the package is stopped. Therefore, if the status of the RFID tag embedded in the ground is monitored periodically, it is possible to quickly grasp the subsidence of the bottom of the package and whether or not the underground cavity is formed.

An important point in the construction of the rapid detection system for ground penetration is to construct a suitable passive RFID tag. Since the tag must be embedded in the bottom of the package, it should be considered that the medium in which the radio waves propagate is not the air condition but the package and the ground structure. Under these conditions, the communication distance over a certain distance should be guaranteed. Because it is for underground burial, a strong housing is required for the tag, and the price of the tag should be low in order to bury it closely below a certain interval. In addition, the reaction speed must be good for the tag to communicate with the mobile antenna / reader on the package.

Generally passive RFID tags are affected by the permittivity of the medium to which the tag is attached, and the resonance frequency changes because the resistance and the capacitor value are changed. Especially, when buried in the ground, due to the characteristic of the soil medium wrapped with the tag, resonance frequency, antenna impedance, radiation pattern, reflection loss are distorted and smooth performance can not be exhibited. In addition, general commercial tags are manufactured considering the characteristics of the environment in the air. Therefore, when applied to the inner layer of the ground, there is a problem that it can not exhibit optimal performance due to a change in characteristics. Furthermore, the structure of the inner layer of the ground is vulnerable to moisture and durability.

Therefore, it has a suitable performance for the inner layer of the ground, has a threshold value that can not be recognized when the sinking occurs, and additionally uses a magnetic magnetic substance of the tag to construct a tag capable of detecting the degree of depression using the strength of magnetic force change It is important to do.

In particular, the ground to which the bottom ground penetration detection technique of the RFID-based package is applied is composed of the pavement structure of the new road or urban railway section, the pavement of the waterway and sewerage pipe replacement section, . If the tags are embedded in these grounds, the characteristics of the soil medium wrapped in the tags are slightly different. Therefore, it is necessary to match the tag matching according to the characteristics of the soil medium. In addition, since the permittivity of the medium differs depending on the characteristics of the soil medium in the applied area, the conjugate matching of the tag should be slightly different for each application region. In the current tag antenna structure for public use, it is difficult to meet the conjugate matching according to various dielectric properties of the soil medium As a result, it is necessary to match the conjugate matching of the tag antenna for laying uniformly, so that the recognition performance of the tag is different according to the applied ground.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view of a tag antenna for ground penetration detection according to an embodiment of the present invention; FIG.

Referring to FIG. 1, an antenna 10 of a tag for ground penetration detection according to an embodiment of the present invention includes a first radiation patch 11 and a second radiation patch 12, And are formed dumbbell-shaped as a whole. The first radiation patch 11 and the second radiation patch 12 are short-circuited by the connection patch 13.

3 and 4), the first radiation patch 11 and the second radiation patch 12 are formed in a circular shape so that the tag can be easily installed on the ground, It is advantageous for the tag construction to have a size of about 50 to 90 mm in diameter.

2, the first radiation patch 11 and the second radiation patch 12 are folded at a vertical angle in the same direction in a state in which the connection patch 13 is set straight, (30).

Since the diameter D of the first radiation patch 11 and the second radiation patch 12 in the antenna 10 is larger than the width W of the connection patch 13, the overall size of the antenna patch 10 is dumbbell- .

Meanwhile, the antenna 10 may be a structured microstrip folded antenna (not a planar antenna) to minimize the size of the tag.

FIG. 2 is a view illustrating a state in which an antenna of a tag for ground penetration detection is folded according to an embodiment of the present invention.

2, the antenna 10 has a first radiation patch 11 horizontally arranged on the lower side and a second radiation patch 12 horizontally on the upper side with respect to the vertically erected connection patch 13, Respectively. That is, the first radiation patch 11 and the second radiation patch 12 are folded at the same angle in the same direction in a state where the connection patch 13 is straight, and the radiation patch 11 has a C-shaped structure as a whole.

The antenna including the first radiation patch 11, the second radiation patch 12 and the connection patch 13 is made of PET (polyethylene telephtalene) and PI (polyimide) resin so as to be easily attached to the package 30 And conductive materials such as copper, aluminum, and silver are laminated on the resin. Here, the thickness of the resin may be within 60 μm, preferably from 40 to 60 μm, and the thickness of the antenna may be within 120 μm, preferably from 80 to 120 μm.

Such a folded structure will reduce the overall volume of the antenna 10 and eventually reduce the size of the package 30 on which the antenna 10 is mounted, thereby achieving miniaturization of the tag.

FIG. 3 is an exploded view of a package of a tag for detecting ground penetration according to an embodiment of the present invention, and FIG. 4 is a package assembly view of a tag for detecting ground penetration according to an embodiment of the present invention.

3 and 4, the package 30 to which the antenna 10 is attached is composed of a base plate 31, a body portion 32, and a lid portion 33.

The bottom plate 31 is formed in a plate shape and an outer side surface thereof is formed with a coupling protrusion 32a for coupling with the lid unit 33. In addition, a receiving groove 31a capable of receiving the magnetic body 20 is formed at the center of the upper surface of the bottom plate 31.

The magnetic body 20 of the receiving groove 31a is for magnetic sensing technology that can be operated in parallel with the RFID antenna 10 described above. The magnetic body 20 can determine whether the magnetic force is detected through the magnetic probe, .

The magnetic body 20 may be fixed to the receiving groove 31a of the base plate 31. The magnetic body 20 may be a neodymium magnet.

The magnetic body 20 acts as an ideal body when buried in the underground, and the presence or absence of the magnetic body will be detected by detecting the magnetic force value through a ground magnetic force gauge. Accordingly, the magnetic force gauge can check the time when the ground subsidence is proceeding. In addition, it is possible to determine whether the ground is submerged or not by monitoring the change in the degree of detection of the ground magnetic body 20 in addition to the method of determining whether the ground is depressed only by sensing the magnetic force value of the magnetic body 20. In the case of detection, it is possible to reduce the error of exploration through the confirmation survey by moving the target area by the moving means, performing the RFID survey quickly, and then performing the magnetic field search for the area where the tag is not recognized. In addition, it is possible to carry out simultaneous RFID inspection and magnetic exploration through tags and concurrently confirm that the underground pavement under the pavement is suspected to be a suspicious area when the two explorations show the same abnormal reaction.

Concrete detection methods related to the magnetic body 20 are well described in the applicant's patent (Patent Application No. 2016-0076599), and therefore, a detailed description thereof will be omitted.

The lid portion 33 is formed in a cylindrical shape, and the opened lower portion is disposed on the upper surface of the bottom plate portion 31 to be engaged. A fitting protrusion 33b is formed on the inner side surface of the lid part 33. The fitting protrusion 33b is inserted into the fitting groove 32c formed on the side of the body part 32, (31) can be engaged. An engaging groove 33a is formed on the outer surface of the lid portion 33 at a position corresponding to the engaging projection 31b of the bottom plate portion 31 so that the engaging groove 33a is inserted into the engaging projection 31b So that the lid portion 33 and the bottom plate portion 31 can be joined together.

In addition, due to the characteristics of the tag embedded in the ground, the joining portions of the bottom plate 31 and the lid portion 33 are treated by ultrasonic welding so that the waterproofing and the dustproofing are performed from the external environment.

On the other hand, the body portion 32 is disposed on the bottom plate portion 31 and is covered by the lid portion 33 to be completely accommodated therein. The body 32 has a ring shape as a whole, and an attachment plate 32d for attaching the antenna 10 is formed inside the ring.

The attachment plate 32d is formed horizontally in the body 32 and has a constant thickness. The thickness of the attachment plate 32d corresponds to the length of the connection patch 13 of the antenna 10.

That is, the connection patch 13 of the antenna 10 is vertically attached to the side surface of the attachment plate 32d, the second radiation patch 12 is horizontally attached to the upper surface of the attachment plate 32d, The first radiation patch 11 is horizontally attached to the lower surface of the plate 32d so that the antenna 10 can be attached to the first radiation patch 11 and the second radiation patch 12 in a state in which the connection patch 13 is straight, Are folded in the same direction at a vertical angle to have a C-shaped structure as a whole.

Meanwhile, according to the present invention, the tag for detecting the ground penetration is embedded in the ground. Especially, since the characteristics of the soil medium surrounding the tag are slightly different from each other, the tag matching is different according to the permittivity characteristics of the soil medium But it has its characteristics.

Domestic RFID UHF readers should use 917 ~ 923.5MHz according to the regulations of radio facilities and have to use 4W or less of radiated power. RFID UHF tags can also achieve maximum performance when entering 917 ~ 923.5MHz.

In order to design the antenna 10 of the tag, an antenna having a value conjugated with the tag chip must be provided for smooth communication. Therefore, the antenna design applying the conjugate matching 27.11 + 201.63j to the chip impedance 27.11-201.65j is performed.

The permittivity of sediments without porosity has a relative dielectric constant of 2.5 in the 1 GHz band, and the dielectric constant of the saturate containing 3.88% of moisture has a relative dielectric constant of 4.5 in the 1 GHz band. It can be seen that the relative dielectric constant of the medium increases with the increase of soil moisture. The change in the relative dielectric constant of the soil medium changes the impedance value of the antenna and causes the resonance frequency to shift, resulting in a performance decay.

When a commercial label tag is used, it is directly affected by the permittivity of the soil, resulting in frequency shift and attenuation of the antenna value. Also, when the density of the soil is increased, the antenna efficiency is significantly lowered, and it is necessary to increase the efficiency by separating the antenna matching portion into various portions.

Accordingly, in the present invention, five matching portions are provided on the antenna 10 and the impedance matching can be adjusted by changing the shape and position of the matching portion. Particularly, the characteristics (the dielectric constant, the density, etc.) ), So that it is possible to provide a tag for the detection of the ground penetration that shows accurate cognitive performance irrespective of the type of the soil medium to be buried.

The matching portion of the antenna 10 is largely composed of five parts. And the dual slot GND matching portions D5 and D5 'are connected to the feed point D1, the dual slot matching portions D2 and D2', the stub matching portions D3 and D3 ', the field direction matching portions D4 and D4' It is divided.

Basically, to design an antenna in UHF band, antenna lengths of 2λ, λ, 2 / λ, 4 / λ, 8 / λ are required. The efficiency of the antenna is better with the use of the original wavelength, but in order to design the antenna of the circular special tag, microstrip folded type is adopted.

UHF band antennas are basically structured using dipole, meander, folded, spiral, monopole, microstrip, etc. T matching and slot matching are mainly used for the matching method. In the present invention, a structural microstrip folded type antenna is used instead of a flat antenna, thereby maximizing the size and efficiency of the tag.

The antenna of the tag changes the capacitance and the inductance value according to the value of the relative dielectric constant of the medium, resulting in a frequency change. In addition, due to the mismatch between the chip and the antenna, a performance damping phenomenon occurs.

5 to 10 are diagrams for explaining impedance matching matching test results of a tag antenna for ground penetration detection according to an embodiment of the present invention.

First, Fig. 5 is a view for explaining the feeding point D1 of the antenna 10. Fig.

The feed point D1 is a point of connection between the tag chip and the antenna 10 and is located on the opposite side of the portion connected to the connection patch 13 in the second radiation patch 12 as shown in FIG. As shown in Fig. In the various matching experiments described later, the position of this feeding point D1 is fixed.

In the present invention, as shown in the figure, the dual-slot matching parts D2 and D2 ', the stub matching parts D3 and D3', the field-direction matching part D4 And D4 'and the dual slot GND matching sections D5 and D5', the antenna radiation efficiency is increased so that the tagging performance is not degraded even if the tag is buried at a specific depth below the package.

6 is a diagram for explaining a dual slot matching unit D2 and D2 'of the antenna 10 and a variable test procedure thereof.

Referring to FIG. 6, the dual slot matching units D2 and D2 'are used to derive double real part matching at the time of impedance matching. The dual slot matching units D2 and D2' Are formed in the form of straight lines horizontally along the longitudinal direction in which they are arranged in a line. The dual slot matching portions D2 and D2 'are formed by two dual slots D2 and D2' formed parallel to each other, and each slot is formed at a left edge position of the connecting patch 13 with a second radiation patch 12 to the right edge. The slot width of such dual slot matching portions D2 and D2 'may be 0.5 to 3 mm.

7 is a view for explaining the stub matching portions D3 and D3 'of the antenna 10 and its variable experimental procedure.

Referring to FIG. 7, the stub matching portions D3 and D3 'compensate the inductance value to compensate for the length of the antenna in the form of folded antennas. The first radiation patch 11, the connection patch 13, The second radiation patches 12 are formed in the form of straight horizontal lines along the longitudinal direction in which they are arranged in a line. The stub matching portions D3 and D3 'are composed of two elongated slots D3 and D3' formed in parallel with each other, and each of the slots has a side surface and a bottom surface on the connecting patch 13, 12 to the right edge of the second radiation patch 12. The slot width of the stub matching portions D3 and D3 'may be 0.5 to 3 mm.

8 is a view for explaining the field direction matching sections D4 and D4 'of the antenna 10 and a variable experimental procedure thereof.

Referring to FIG. 8, the electric field direction matching portions D4 and D4 'are provided to increase the antenna gain value when forming the folded type antenna and to facilitate conjugate matching according to the position of the chip. 11, the connecting patch 13 and the second radiation patch 12 are arranged in a line in the longitudinal direction and in the vertical direction in the form of a meander line. The electric field direction matching portions D4 and D4 'are formed in the direction perpendicular to the longitudinal direction in which the dual slot matching portions D2 and D2' are formed in the dual slot matching portions D2 and D2 ' Two curved meander line slots D4 and D4 'are made up of dual. Each of the slots D4 and D4 'extends in the vertical direction in the slots D2 and D2' of the dual slot matching portions D2 and D2 ', and the two meander line slots D4 and D4' (That is, the outward direction of the connection patch 13) so that the two electric field direction matching portions D4 and D4 'do not meet.

9 is a view for explaining the dual slot GND matching units D5 and D5 'of the antenna 10 and its variable experimental procedure.

9, the dual slot GND matching units D5 and D5 'are provided for raising the gain value of the antenna and include a first radiation patch 11, a connection patch 13 and a second radiation patch 12 in a line. Are formed in the form of straight horizontal lines arranged along the longitudinal direction in which they are arranged. The dual slot GND matching portions D5 and D5 'are connected to the dual slot matching portions D2 and D2' at the points where the dual slot matching portions D2 and D2 'and the field direction matching portions D4 and D4' D2 ', D2'), that is, in the direction opposite to the forming direction of the first radiation patch 11, and are parallel to each other.

In the present invention, a variable is applied to the dual slot matching parts D2 and D2 'at a single frequency of 920 MHz to induce matching of resistance components.

Table 1 below shows the lengths of the feed point D1, the stub matching portions D3 and D3 ', the field direction matching portions D4 and D4' and the dual slot GND matching portions D5 and D5 ' The length of the dual slot matching portions D2 and D2 'is extended horizontally in units of 1 mm from the position of the reference point D2S0 to the position of the outer side D2S5 of the second radiation patch 12, This is the result of measuring the reactance. Here, the position of the reference point D2S0 is located on the right side of the second radiation patch 12, and the lengths of D2 and D2 'are simultaneously changed.

Dual slot impedance matching portion Variable D2
Fixed D1 = 0mm
D3 = 0 mm
D4 = 0 mm
D5 = 0 mm
Freq. 920MHz


Z (Re)



Z (Im) D2S0 0 mm 42.28 350.5 D2S1 1 mm 39.27 340.6 D2S2 2 mm 38.68 337.65 D2S3 3 mm 35.87 335.78 D2S4 4 mm 33.27 330.45 D2S5 5 mm 31.12 327.7

As shown in Table 1, when the matching slot loop from 0 mm to 5 mm is changed, the resistance value of the antenna gradually decreases and the inductance value decreases. In order to conjugate the resistance component of the antenna to the chip first, a 5mm section approximate to 27.11 is fixed.

In the case of a commercial label antenna, the technique is used to reduce the size of the tag, and the efficiency of the antenna is reduced. By using the microstrip folded structure, the overall length of the antenna is insufficient. To compensate for the existing antenna length, a stub is used for the upper circular emitter. Such stubs are formed by dual stub matching portions D3 and D3 '.

The length of the stub has an absolute effect on the impedance matching between the tag chip and the antenna. If the length of the stub is long or short, the antenna efficiency is attenuated.

In the following Table 2, the dual slot matching portions D2 and D2 'are fixed to the matching point D2S5 which is expanded in the horizontal direction by 5 mm from the reference point D2S0 according to the experimental results of Table 1, The lengths of the electric field direction matching portions D4 and D4 'and the dual slot GND matching portions D5 and D5' are fixed to the reference point and the length of the stub match portions D3 and D3 ' To the position of D3S5 on the outer side of the second radiation patch 12 in the horizontal direction by 1 mm unit, and the resistance and the reactance were measured. Here, the position of the reference point D3S0 is located on the right side of the second radiation patch 12, and the lengths of D3 and D3 'are simultaneously changed.

The stub inductance impedance matching portion Variable D3
Fixed D1 = 0mm
D2 = 5 mm
D4 = 0 mm
D5 = 0 mm
Freq. 920MHz


Z (Re)



Z (Im) D3S0 0 mm 31.12 327.7 D3S1 1 mm 30.0 325.79 D3S2 2 mm 29.89 323.58 D3S3 3 mm 29.65 320.89 D3S4 4 mm 29.5 318.74 D3S5 5 mm 29.14 315.78

The stub length of the stub matching portions D3 and D3 'is adjusted to adjust the inductance value of the antenna by fixing the resistance value close to the chip impedance. Here, after the dual slot matching portions D2 and D2 'are fixed to the matching point D2S5, the lengths D3 and D3' are adjusted between 0 mm and 5 mm in 1 mm increments. As can be seen from Table 2, it can be seen that the resistance component decreases and the inductance component decreases in the D3S5 region of 5 mm.

On the other hand, in the case of the conventional injection type tag, side direction slot matching is used to determine the direction of the electric field and the direction of the magnetic field but does not play a role of fine adjustment of the impedance. According to the present invention, the field direction matching sections D4 and D4 'are formed as the microstrip lines in the area of the dual slots on the side surface to finely adjust the impedances to precisely align the antennas and increase the antenna efficiency.

In the following Table 3, the dual slot matching portions D2 and D2 'and the stub matching portions D3 and D3' extend horizontally by 5 mm from the reference points D2S0 and D3S0 according to the results of Table 1 and Table 2 And the length of the feed point D1 and the dual slot GND matching sections D5 and D5 'are fixed to the reference points, and the lengths of the electric field direction matching sections D4 and D4' The length is extended horizontally in the unit of 1 mm from the position of the reference point D4S0 to the position of the outer side D4S5 of the second radiation patch 12, and the resistance and the reactance are measured.

Here, the field direction matching portions D4 and D4 'are formed as meander lines formed in a zigzag shape with a plurality of bent portions. The line shape of the field direction matching portions D4 and D4 'in the present invention has five bent portions after extending in the vertical direction in the dual slot matching portions D2 and D2' of the connecting patch 13, A horizontal line extending from the first radiation patch 11 is formed horizontally along the longitudinal direction in which the first radiation patch 11, the connection patch 13, and the second radiation patch 12 are arranged in a line. The length of the horizontal line extending from the last bending portion is expanded horizontally in the unit of 1 mm from the position of the reference point D4S0 to the position of the outer side D4S5 of the second radiation patch 12 to change the resistance and reactance The results are shown in Table 3 below. At this time, the position of the reference point D4S0 is located in the connection patch 13, and the lengths of D3 and D4 'are simultaneously changed.

The micro-strip microstrip line impedance matching portion Variable D4
Fixed D1 = 0mm
D2 = 5 mm
D3 = 5 mm
D5 = 0 mm
Freq. 920MHz


Z (Re)



Z (Im) D4S0 0 mm 29.14 315.78 D4S1 1 mm 31.05 301.52 D4S2 2 mm 32.26 298.1 D4S3 3 mm 33.78 280.3 D4S4 4 mm 34.65 278.52 D4S5 5 mm 35.25 270.45

As shown in Table 3, when the micro-end microstrip length of the field-direction matching portions D4 and D4 'was adjusted between 0 mm and 5 mm in 1 mm increments, the increase in resistance component and the increase in inductance component in the 5 mm interval D4S5 It is possible to confirm that the impedance is fine, adjust the impedance to precisely match the antenna, and increase the antenna efficiency.

In the following Table 4, the dual slot matching portions D2 and D2 ', the stub matching portions D3 and D3' and the field direction matching portions D4 and D4 ' D5S0, D3S0 and D4S0 in the horizontal direction and fixed to the variable matching points D2S5, D3S5 and D4S5 while the feed point D1 is fixed to the reference point and the dual slot GND matching portions D5 and D5 'Is extended horizontally in the unit of 1 mm from the position of the reference point D5S0 to the position of the position D5S5 of the direction of the first radiation patch 11, and the resistance and the reactance are measured. Here, the position of the reference point D5S0 is located in the connection patch 13, and the lengths of D3 and D4 'are simultaneously changed.

Dual slot GND impedance matching part Variable D5
Fixed D1 = 0mm
D2 = 5 mm
D3 = 5 mm
D4 = 5 mm
Freq. 920MHz


Z (Re)



Z (Im) D5S0 0 mm 35.25 270.45 D5S1 1 mm 34.89 260.24 D5S2 2 mm 33.28 254.1 D5S3 3 mm 32.58 250.2 D5S4 4 mm 31.59 246.3 D5S5 5 mm 30.97 230.87

As shown in Table 4, when the length of the dual slot GND matching portions D5 and D5 'is adjusted in the range of 0 mm to 5 mm in 1 mm increments, the resistance component decreases and the inductance component decreases most in the 5 mm section of D4S5 I could confirm.

10 is a view for explaining the antenna 10 whose slot length is finally determined.

According to the experimental results, the variable lengths of the dual slot matching portions D2 and D2 ', the stub matching portions D3 and D3' and the dual slot GND matching portions D5 and D5 'are fixed to the matching points D2S5, D3S5 and D5S5 And finally the electric field direction matching portions D4 and D4 'are adjusted to finely adjust the impedance value.

Therefore, by precisely adjusting the impedance value according to the kind of the soil medium in which the tag is embedded, accurate cognitive performance can be ensured without being influenced by the kind of the soil medium.

Table 5 shows the performance of the finally determined tag.

Performance of the final special tag frequency Antenna impedance value Antenna gain (dBi) Recognition distance (Cm)
Freq. 920MHz
26.11 + 211.84j
3.7dBi ~ 50Cm can be recognized

~ 60Cm not recognized
(It can not be recognized when the tag sinks due to the pupil)

Finally, the tag for the customized ground penetration detection gets 3.7 dBi of antenna gain when installed inside the soil. In the packaging section, spatial packaging is performed to minimize the change in permittivity transferred according to the proximity of the tag antenna and the soil. The impedance matching is induced by varying the matching area of the tag antenna, and then the efficiency Performance).

Determination of the tag burial depth is a very important factor in the present invention. In general, the communication distance of the UHF band passive tag is up to 12m. This is the case where the medium is air and there are no obstacles in the middle. In the present invention, since the tag is buried in the ground, the medium in which radio waves propagate is a package structure. The pavement is mainly classified into concrete pavement and asphalt pavement. In general, the urban road is mostly composed of asphalt pavement, and its structure is composed of asphalt, middle layer, base layer, supporting layer, roadbed and road surface. The type and thickness of each layer in the pavement cross section of the pavement design differ slightly depending on the nature of the road and the allowable load size.

If the underground cavity underneath the pavement is created with a certain cause and the cause continues, the size of the underground cavity will gradually increase. The rate at which the creation and scale of the underground cavity develops depends on various environmental factors, which can either be rapid or slow over several decades. The asphalt concrete and base layer which form the surface layer above the pavement have a considerable strength and bear the load of the road which acts on the road for a specific period even when the roadbed and the road surface are depressed. If cracks develop in the surface layer due to the continuous load, or if the underground cavity of the lower part becomes larger in size horizontally, the surface layer will not survive the load, it will be destroyed and lead to road depression. Generally, the pavement is composed of 20cm of asphalt layer and 10cm of asphalt surface layer on the upper part of the auxiliary layer 30cm, but it can be changed depending on road characteristics and allowable shear. In actual asphalt road pavement, asphalt with excellent adhesive strength hardens the coarse-grained material in the base layer and the surface layer. In the case of the auxiliary layer, the cement paste is used in addition to compaction for stabilization at the time of laying. Compared to roadbed and roadbed, particles have excellent bond strength. On the other hand, since the bedrock and hearth are pure ground materials with no additive giving particle binding force, there may be particle movement and collapse due to gravity, and the reduction of the particle binding force due to an increase in water content can accelerate this. In addition, when water in the ground is formed, the loosened particles move along the water path. That is, the underground cavity formed at a specific depth is expanded to the upper part while expanding through continuous collapse and particle loss. However, as shown in FIG. 6, when the auxiliary cavity layer having some binding force is encountered, And the size of that.

In view of the process from the generation of the underground cavity to the road depression, it is preferable that the tag according to the present invention is installed at the upper part of the auxiliary equipment layer, the bedrock boundary or the bedrock. Therefore, the tags to be used must have a communication distance of about 40 cm to 60 cm, preferably about 50 cm, in the package structure medium. For this purpose, the tag 10 has a depth of 40 cm to 60 cm, It is effective to be buried in the depth of degree.

The feed point D1, the dual slot matching portions D2 and D2 ', the stub matching portions D3 and D3', the field direction matching portions D4 and D2 ' D4 ') and dual-slot GND matching sections (D5, D5') to induce matching, thereby reducing performance degradation due to chip-to-antenna mismatch depending on the permittivity of the soil medium and ensuring uniform tagging performance Will be.

As described above, an optimal embodiment has been disclosed in the drawings and specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: antenna 11: first radiation patch
12: second radiation patch 13: connection patch
20: magnetic body 30: package
31: base plate portion 32: body portion
33:

Claims (9)

A tag that is embedded in the ground and can be recognized through a reader moving on the ground,
An antenna for transmitting and receiving signals to and from the reader through the ground according to the tagging of the reader;
A body portion to which the antenna is attached;
A base plate formed in a plate shape and supporting the body portion; And
A lid part which is formed in a cylindrical shape and accommodates the body part and engages with the bottom plate part; / RTI >
The antenna is formed in a dumbbell shape in which a circular first radiation patch and a second radiation patch are connected to both ends with a connection patch as a center,
The first radiation patch and the second radiation patch are folded at a vertical angle in the same direction with respect to the connection patch in a state in which the connection patch is straight up when attached to the body,
The antenna in the unfolded state is formed with a dual slot matching portion in the form of a straight line horizontal along the longitudinal direction in which the first radiation patch, the connection patch and the second radiation patch are arranged in a row,
The dual slot matching part is formed by two dual slots which are formed parallel to each other. Each slot extends from the left edge of the connection patch to the right edge of the second radiation patch,
And wherein a resistance and an inductance of the antenna are adjusted according to a length of a slot constituting the dual slot matching unit.
delete delete The method according to claim 1,
The antenna in the unfolded state is formed with a linear line-shaped stub-matching portion along the longitudinal direction in which the first radiation patch, the connection patch and the second radiation patch are arranged in a row,
The stub matching portion is composed of two elongated slots formed parallel to each other, each slot extending from a point at which the upper and lower sides of the connecting patch meet the second radiation patch to the right edge of the second radiation patch Respectively,
Wherein a resistance and an inductance of the antenna are adjusted according to a length of a stub constituting the stub matching unit.
5. The method of claim 4,
The antenna in the unfolded state is formed with a field direction matching portion in the form of a meander line in a direction perpendicular to the longitudinal direction in which the first radiation patch, the connection patch and the second radiation patch are arranged in a row,
Wherein the electric field direction matching portion is formed by two dual bent meander line slots formed in a direction orthogonal to the longitudinal direction in which the dual slot matching portion is formed in the dual slot matching portion of the connection patch, And extending in the vertical direction in each of the slots of the sub-
Wherein the antenna has a characteristic that a resistance and an inductance of the antenna are adjusted according to a length of a horizontal line extending from a last bent portion of the electric field direction matching portion.
6. The method of claim 5,
In the unfolded antenna, a dual slot GND matching portion in the form of a straight line is formed along the longitudinal direction in which the first radiation patch, the connection patch and the second radiation patch are arranged in a row,
The dual slot GND matching unit includes two long slots formed in parallel to each other and having a horizontal straight line shape in a direction opposite to the formation direction of the dual slot matching unit at a point where the dual slot matching unit and the field direction matching unit meet, Lt; / RTI >
Wherein the antenna has a characteristic that a resistance and an inductance of the antenna are adjusted according to a length of a slot constituting the dual slot GND matching unit.
The method according to claim 1,
The bottom plate has a receiving groove formed at an upper center thereof for receiving a magnetic substance,
Wherein the magnetic body accommodated in the receiving groove is capable of determining whether the magnetic force is detected through a magnetic force probe moving on the ground or not.
The method according to claim 1,
The body portion is disposed on the bottom plate portion and is covered by the lid portion to be received therein,
Wherein an attachment plate for attaching the antenna is formed on the body portion,
And a second radiation patch is attached horizontally to the upper surface of the attachment plate on the upper surface of the attachment plate, and a first radiation patch is attached to the lower surface of the attachment plate on the lower surface of the attachment plate, So that the antenna has a folded shape of a C-shaped structure.
The method according to claim 1,
A fitting protrusion is formed on an inner side surface of the lid part. The fitting protrusion is fitted into a fitting groove formed on a side of the body part. A coupling groove is formed on an outer surface of the lid part at a position corresponding to a coupling protrusion of the outer surface of the bottom plate part By engaging the engaging groove with the engaging projection, the lid portion and the bottom plate portion are engaged with each other,
And a joining portion between the bottom plate and the lid is ultrasonic welded.

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