KR100819201B1 - HF Band Passive RDF Metal Tag Antenna Using Indirect Coupled Feeding - Google Patents

Abstract

A passive type RFID(Radio Frequency Identifier) tag antenna of a UHF band using an indirect coupling feed is provided to reduce a manufacturing cost of a tag antenna and minimize a size of the tag antenna by forming and supporting a dielectric substrate without a vertical structure or a short circuit pin. A passive type RFID tag antenna of a UHF band using an indirect coupling feed includes a first substrate(100), a dielectric substrate(200), and a second substrate(300). A ground unit(110) is formed on a lower part of the first substrate. A feeding unit of a symmetric meander line is formed on an upper part of the first substrate. The dielectric substrate is formed on an upper layer of the substrate. A radiation unit of a dipole structure and a slot corresponding to a feeding line of the symmetric meander line are formed on an upper layer of the dielectric substrate. The feeding line of the symmetric meander line formed on the first substrate further has an IC(Integrated Circuit) chip which supplies a signal and a power.

Description

 HF Band Passive RDF Metal Tag Antenna Using Indirect Coupled Feeding {Design of UHF Band RFID Metal Tag Antenna Using Proximity Coupled Feed}

1 is a perspective view of a UHF band passive RFID metal tag antenna using indirect coupled feeding according to an embodiment of the present invention

2 is a side view of a UHF band passive RFID metal tag antenna using indirect coupled power feeding according to FIG. 1 of the present invention.

3 is a front view showing a top surface of the first substrate according to FIG. 1 of the present invention;

4 is a front view showing a top surface of the second substrate according to FIG. 1 of the present invention;

5 is an equivalent circuit diagram of a coupling-coupled feed according to FIG. 1 of the present invention.

6 is a view showing a simulation result and the actual measurement impedance of the power supply unit according to FIG. 1 of the present invention;

7 is a view showing a simulation result and the actual measurement impedance according to FIG. 1 of the present invention;

8 is a view showing the impedance on the Smith chart according to Figure 1 of the present invention

9 is a view showing a return loss according to FIG. 1 of the present invention

10 is a view showing a change in the radiation pattern according to the size of the attachment surface according to Figure 1 of the present invention

* Description of the main drawing codes *

100: first substrate 110: ground portion

120: feeder 121: feed point

130: IC chip 200: dielectric substrate

300: second substrate 310: slot

320: radiating part A, B: opening point

The present invention relates to a UHF band passive RFID metal tag antenna using indirectly coupled power supply, and more particularly, a first substrate having a ground part formed at a lower part thereof, and a feed part of a symmetric meander line formed at an upper part thereof. An IC chip is formed at the center of the feeder of the Ander line to supply a signal, and a feed point is formed at both ends, and a dielectric substrate formed on the upper layer of the first substrate and the symmetric meander line on the upper layer of the dielectric substrate. It relates to a tag antenna, characterized in that consisting of a slot corresponding to the feed portion and a second substrate on which the radiating portion of the dipole structure is formed.

As a technique related to a conventional tag antenna, Korean Laid-Open Patent Publication No. 10-2006-0101204 arranges a dipole portion shorter than 1/2 lambda of the antenna resonant wavelength and makes it possible to feed power from the feed portion to the chip. An inductance section for adjusting the inductance of the antenna to sandwich the feed section is provided. The inductance part is installed using the space inside the rolled-up dipole part. By providing the inductance section, the inductance of the antenna is adjusted to resonate with the capacity of the chip connected to the power supply section at a predetermined frequency. At this time, the radiation resistance of the antenna is very large in calculation, but in practice, it is a technology that is almost the same as the resistance of the chip due to the loss can supply power received from the antenna to the chip.

However, the conventional technology has a problem in that the performance of the tag antenna is changed according to the characteristics of the object to which the tag antenna is attached and the operating environment consisting of a feed part, a dipole part, and an end on which a chip is mounted.

Accordingly, the present invention has been made to solve the above problems, and the object of the present invention is conjugate matching with the impedance of the IC chip and the ground part is formed by itself, so that the antenna performance changes even when the tag antenna is attached at any position. Since the radiating part of the dipole structure resonates at 1 / 2λ and is fed by coupling with the feeding part of the meander line, it is a simple structure that forms and supports a dielectric substrate without the need for a shorting pin or a vertical structure. The object of the present invention is to provide a tag antenna having a low cost and a small size.

In order to achieve the above object, a UHF band passive RFID metal tag antenna using indirectly coupled power feeding according to an embodiment of the present invention includes a first substrate having a ground portion formed at a lower portion thereof and a feed portion of a symmetric meander line formed at an upper portion thereof; A dielectric substrate formed on an upper layer of the first substrate, and a second substrate formed on the upper layer of the dielectric substrate and a slot corresponding to the feed portion of the symmetric meander line and the radiation portion of the dipole structure.

According to an embodiment of the present invention, the feeding part of the symmetric meander line formed on the first substrate may further include an IC chip for supplying signals and power.

According to an embodiment of the present invention, the symmetric meander line feeder formed on the first substrate is formed to correspond to the slot formed on the second substrate so as to minimize signal interference.

According to an embodiment of the present invention, the feeding part of the symmetric meander line formed on the first substrate is characterized in that each feeding point for feeding a signal to the radiating part formed on the second substrate.

According to an embodiment of the present invention, the feed points formed at both ends of the feed part of the symmetrical meander line formed on the first substrate may be coupled to the radiating part formed on the second substrate by coupling.

According to one embodiment of the present invention, the feed portion of the symmetric meander line formed on the first substrate is formed at both ends of the feed portion and the radiating portion to minimize parasitic capacitance components that may occur. The overlapping area except for the feed point is formed to be minimized.

According to one embodiment of the present invention, the feeder of the symmetric meander line formed on the first substrate is characterized in that the input resistance is adjusted by modifying the lengths of the feed points formed at both ends.

According to an embodiment of the present invention, the material of the first substrate is FR4, and the material of the dielectric substrate formed on the upper layer of the first substrate is air or foam.

According to an embodiment of the present invention, the radiation part formed on the second substrate is characterized in that the resonance at 1 / 2λ.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view of a UHF band passive RFID metal tag antenna using indirect coupled feeding according to an embodiment of the present invention, Figure 2 is a UHF band passive RFID metal tag antenna using an indirect coupled feeding according to Figure 1 of the present invention As a side view, a ground portion 110 is formed at the bottom and a symmetrical meander line feed portion 120 is formed at the top, and the IC chip 130 is formed at the center of the feed portion 120 of the meander line. The first substrate 100, the dielectric substrate 200 formed on the upper layer of the first substrate 100, and the feed part 120 of the meander line symmetric to the upper layer of the dielectric substrate 200. The slot 310 is formed of a second substrate 300 on which a radiating part 320 having a dipole structure is formed.

More specifically, the first substrate 100 is made of a material of 89 × 19mm size and FR4, the ground portion 110 for grounding the signal is formed at the bottom, the IC for supplying the signal and power at the top The chip 130 is formed, and the feed part 120 of the meander line symmetrical with respect to the IC chip 130 is formed, and the feed point 121 is formed at both ends of the feed part 120. do.

The feeder 120 is transmitted along a meander line in which signal power formed from the IC chip 130 is symmetrically formed, and the transmitted signal is provided at both ends of the meander line feeder 120 symmetrically formed. By being induced at the feed point 121 formed, it is finally coupled to the radiating part 320 formed on the second substrate 300 by coupling.

In addition, the feeder 120 of the symmetric meander line corresponds to the slot 310 formed in the second substrate 300 to reduce signal interference with the radiator 320 formed in the second substrate 300. Is formed.

In particular, the tag antenna of the present invention has a size of 89 × 19 × 5.5 mm and is conjugately matched with the impedance of the IC chip 130 formed in the power supply unit 120, and because the ground unit 110 is formed on its own, the metal It is attachable to the material.

In addition, the radiating unit 320 resonates at 1 / 2λ like the dipole antenna, and is coupled and fed to the feed points 121 formed at both ends of the feed unit 120 of the symmetrical meander line, respectively. There is no short circuit pin or vertical structure to form a simple structure that is fixedly supported by the dielectric substrate 200.

Therefore, since there is no electrical short circuit between the radiating part 320, the power feeding part 120 and the grounding part 110, the characteristic change of the tag antenna according to the change of the attachment surface to which the tag antenna is attached is reduced. It is light in weight, inexpensive, and coupled with coupling, which has broadband antenna characteristics.

3 is a front view showing an upper surface of the first substrate according to FIG. 1 of the present invention, in which an IC chip 130 in which signal power is formed is formed at the center and is symmetrically to the left and right sides of the IC chip 130. A feed point 121 is formed at both ends of the feed part 120 and the feed part 120 of the formed meander line.

In more detail, the IC chip 130 forms signal power using a chip (= 9-j127Ω) manufactured by Alien Corporation, and the shape of the feeder unit 120 of the meander line formed symmetrically to the left and right sides. The signal power is transmitted, and the feed point 121 formed at both ends of the feed part 120 of the symmetrically formed meander line and the radiator 320 formed on the second substrate 300 are coupled to each other. Will be combined.

In addition, the feed part 120 of the symmetrically formed meander line is formed to correspond to the slot 310 formed in the second substrate 300, respectively, to suppress signal interference.

4 is a front view illustrating a top surface of a second substrate according to FIG. 1 of the present invention, wherein the second substrate 300 corresponds to the feed part 120 of the symmetric meander line of the first substrate 100. And a radiating part 320 having a dipole structure formed to correspond to the feeding point 121 formed at both ends of the feeding part 120 of the first substrate 100.

More specifically, the radiator 320 is resonant at 1 / 2λ and is coupled to each of the feed points 121 formed on the first substrate 100 by coupling to receive a signal.

FIG. 5 is an equivalent circuit diagram of a coupling coupling feed according to FIG. 1 of the present invention, in which a parallel RLC resonant circuit and a coupling capacitor are connected in series. The coupling capacitor value is an important parameter in impedance matching of an antenna. Is operated.

In addition, the type or thickness of the substrate used in the stacked tag antenna is an important variable to improve the bandwidth.

Therefore, the tag antenna of the present invention has a wider bandwidth by a feeding method coupled with a coupling, and is structurally simple because no electrical coupling is required between the radiating unit 320 and the feeding unit 120. It can be seen that there is an advantage in reducing costs.

6 is a view showing a simulation result and the actual measurement impedance of the power supply unit according to Figure 1 of the present invention, Figure 7 is a view showing a simulation result and the actual measurement impedance according to Figure 1 of the present invention, the tag antenna of the present invention Is attached to the attachment surface of size 1/2 and includes the radiating part 320, and the result of using the simulation tool for the impedance value of the tag antenna and the actual measured value using the Agilent's E5071B. To indicate.

More specifically, the impedance of the tag antenna should have a high inductance value with a small resistance in order to have a complex conjugate value of the impedance of the IC chip 130, so that sufficient inductance value and at least in the power supply 120 itself It can be seen that it should have a resistance component of, FIG. 6 shows the resistance and reactance values according to the frequency of the feeder, and FIG. 7 shows the resistance and reactance values of the tag antenna including the radiator 320. .

FIG. 8 is a diagram illustrating an impedance on a Smith chart according to FIG. 1 of the present invention. The reactance component of the tag antenna may be adjusted by adjusting the length of the feeding part 120 of the symmetrically formed meander line.

In addition, when the length of the feeder 120 of the symmetrically formed meander line is reduced, the impedance locus moves in the direction of power on the Smith chart, and when the length of the feeder 120 of the symmetrically formed meander line is increased, the impedance is increased. The locus moves in the load direction, and the input resistance component of the tag antenna depends on the coupling coefficient between the radiator 320 and the feeder 120.

Accordingly, it can be seen that the input resistance can be adjusted by adjusting the distances of the opening points A and B of the feed part 120 of the meander line symmetrically formed, and the interval between the opening points A and B is The narrower the impedance locus, the larger the bandwidth can not be satisfied, the wider the gap between the opening point (A, B), the coupling coefficient is reduced, the resonance is to be adjusted properly.

FIG. 9 is a diagram illustrating a return loss according to FIG. 1 of the present invention, and illustrates a return loss normalized based on an impedance of an IC chip based on an impedance calculated by a tag antenna and a network analyzer. .

More specifically, it can be seen that the calculated value and the actual measured value match, and the bandwidth of the measured 3dB return loss is 55 MHz wideband.

10 is a view showing a change in the radiation pattern according to the size of the attachment surface according to Figure 1 of the present invention, the tag measured by displaying the minimum output power of the RFID reader for operating the tag antenna in the electromagnetic anechoic chamber for each angle It represents the normalized radiation pattern of the antenna.

In detail, as a result of comparing the radiation pattern when contacting the metal adhesion surface of 1 / 2λ and the metal adhesion surface of 1λ, the change in the principal leaf direction of the radiation pattern with respect to the metal adhesion surface is almost It can be seen that the size of the posterior lobe changes.

Therefore, the measured maximum recognition distance according to the change of the size of the metal adhesion surface in contact is 3.5m at 1 / 2λ and 5m at 1λ, respectively, so that the tag antenna has no significant change in performance depending on the changing ground plane size. .

The present invention has been described in detail so far, but the embodiments mentioned in the process are only illustrative and are not intended to be limiting, and the present invention is provided by the following claims and the technical spirit and field of the present invention. Within the scope not departing from the scope of the present invention, changes in the components that can be coped evenly will fall within the scope of the present invention.

 As described above, the present invention is conjugated with the impedance of the IC chip, and the ground part is formed by itself, so that the tag antenna can be used without any change in the antenna performance even when attached to any position, and the dipole structure Since the radiating part resonates at 1 / 2λ and is fed by the feeding part of the meander line, it is a simple structure that is supported by forming a dielectric substrate without the need of a shorting pin or vertical structure. It has the effect of miniaturization.

Claims (9)

A first substrate having a ground portion formed at a lower portion thereof and a feed portion of a symmetrical meander line formed at an upper portion thereof; A dielectric substrate formed on the upper layer of the first substrate; And UHF band passive RFID metal tag antenna using indirectly coupled feeding, characterized in that the upper layer of the dielectric substrate consisting of a second substrate is formed with a slot corresponding to the feed portion of the symmetrical meander line and the dipole structure. The UHF band passive RFID metal tag antenna of claim 1, wherein the feeder of the symmetric meander line formed on the first substrate further comprises an IC chip for supplying a signal and power. The method of claim 1 or 2, wherein the symmetric meander line feeder formed on the first substrate is formed to correspond to the slot formed on the second substrate to minimize signal interference. UHF Band Passive RFID Metal Tag Antenna. The UHF of claim 3, wherein a feed point of a symmetric meander line formed on the first substrate is provided with a feed point for feeding a signal to a radiation portion formed on the second substrate, respectively. Band passive RFID metal tag antenna. The indirectly-coupled feed according to claim 4, wherein the feed points formed at both ends of the feed section of the symmetric meander line formed on the first substrate are coupled to the radiating section formed on the second substrate by coupling. Passive RFID Metal Tag Antenna Using UHF Band. The feeding part of the symmetrical meander line formed on the first substrate, wherein both ends of the feeding part and feeding points of the radiating part are minimized to minimize parasitic capacitance components that may occur. UHF band passive RFID metal tag antenna using indirect coupled feeding, characterized in that the overlapping area is formed to minimize. 6. The UHF of claim 5, wherein the feeding part of the symmetric meander line formed on the first substrate adjusts input resistance by varying the length of each feeding point formed at each end. Band passive RFID metal tag antenna. 8. The UHF band passive RFID metal tag antenna according to claim 7, wherein the first substrate is made of FR4, and the dielectric substrate formed on the upper layer of the first substrate is made of air or foam. The UHF band passive RFID metal tag antenna according to claim 5, wherein the radiating portion formed on the second substrate resonates at 1 / 2λ.

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