KR101151833B1 - Antenna for Near Field Communication and Radio Frequency IDentification Reader Having the Same - Google Patents

Abstract

The present invention relates to an antenna for a short range wireless communication and an RFID reader including the same, wherein one end is connected to an antenna port, the other end is connected to ground, and a signal supply unit supplying a signal input to the antenna port, and connected to the signal supply unit. A balun unit for converting a signal supplied from the signal supply unit into a 0 to 180 degree phase as a balanced signal, a resonator unit connected to the balun unit and resonating the phase-converted signal, and disposed between both ends of the resonator unit Load impedance to be formed.

Description

Antenna for near field communication and RDF reader comprising same {Antenna for Near Field Communication and Radio Frequency IDentification Reader Having the Same}

The present invention relates to an antenna for short range wireless communication and an RFID reader including the same. More particularly, the present invention is used in an ultra high frequency (UHF) radio frequency identification (RFID) reader antenna, and uses a near field of the antenna. The present invention relates to an antenna for short range wireless communication for recognizing an object having a plurality of small tags attached thereto and an RFID reader including the same.

In the field of RFID, the area of the RFID is expanded to individual items. In general, high frequency (HF) band RFID technology has been preferred for the recognition of individual items, but the tag size, price, recognition distance and data processing speed, and compatibility with the existing UHF band RFID standard It has been a problem.

The RFID technology of the HF band uses a magnetic coupling method, whereas the RFID technology of the UHF band uses a back scattering method of electromagnetic waves. RFID of UHF band is widely used because it has a relatively long advantage than RFID of HF band with recognition distance of 3 ~ 5m.

However, the RFID of the UHF band has a problem that the recognition rate is drastically decreased due to scattering and interference of electromagnetic waves in an application field in which a large number of articles are recognized as individual item units. In order to overcome this problem, the development of RFID technology using the near field of the UHF band has been actively conducted.

When using the near field of the UHF band, unlike the HF band using the magnetic field coupling method, it is possible to recognize a large amount of individual items by appropriately selecting the magnetic field coupling method and the electric field coupling method according to the tagged goods and the service environment. Can be.

However, because the near-field antenna of the UHF band has a high operating frequency and a short wavelength of radio waves, there is a problem in that a null point where a signal is not recognized in the near field often occurs. Since the operating frequency of the reader antenna changes, there is a problem in that the performance of the RFID reader antenna changes with the change in the number of articles.

The present invention provides an antenna for short range wireless communication and an RFID reader including the same, which can maintain a constant performance regardless of the number of articles without a shadow portion occurring in the near field.

According to an aspect of the present invention, one end is connected to the antenna port, the other end is connected to the ground and the signal supply unit for supplying a signal input to the antenna port, the signal supply unit is connected to the signal supply and the signal supplied from the signal supply unit 0 degree Provided is a short range wireless communication antenna including a balun converting to a 180 degree phase, a resonating part connected to the balun and resonating the phase-converted signal, and a load impedance disposed between both ends of the resonating part to form a loop.

The signal supply unit may be formed of any one of a straight feed line or a strip line.

The balun may be configured as any one of a coupling transmission line, a lumped element circuit, or a hybrid structure in which the coupled transmission line and the lumped element circuit are combined.

The resonator may include a unit resonator configured to resonate a phase-converted signal, and the plurality of unit resonators may be formed in series.

The unit resonator may be formed of a spiral inductor and a chip capacitor or a strip line and a chip capacitor.

The unit resonator may have a pair of resonant circuits including one inductor and one capacitor disposed side by side in a direction in which current flows.

A plurality of unit resonators may be disposed in the longitudinal direction in which current flows.

The load impedance may be made of a resistor.

The load impedance may be connected at one end to ground.

The short range wireless communication antenna further includes a dielectric layer, and a signal supply line may be formed on an upper surface of the dielectric layer and a ground may be formed on the lower surface of the dielectric layer.

According to another aspect of the present invention, one end is connected to the antenna port, the other end is connected to the ground and the signal supply unit for supplying a signal input to the antenna port, the signal supply unit is connected to the signal supply and the signal supplied from the signal supply unit 0 degree The article includes an antenna and an antenna including a balun portion converting to a 180 degree phase, a resonator portion connected to the balun portion and resonating the phase-converted signal, and a load impedance disposed between both ends of the resonator portion to form a loop. Provided is an RFID reader including a receiver for receiving information from an attached RFID tag.

According to the present invention, there is an effect that the shadow portion does not occur in the near field while using the frequency of the UHF band.

In addition, even when a plurality of articles are densely placed on the upper surface of the RFID antenna, it is possible to accurately obtain information of the RFID tag without changing the frequency by using the frequency of the UHF band.

1 is a block diagram showing an embodiment of an antenna for short range wireless communication according to an aspect of the present invention.
2A to 2D are diagrams illustrating an embodiment of a unit resonance unit of a short range wireless communication antenna according to an aspect of the present invention.
3 is a diagram illustrating a radiation pattern according to an embodiment of a magnetic field formed around an antenna for short range wireless communication according to an aspect of the present invention.
4 is a view showing a radiation pattern of a far field magnetic field of the antenna for short range wireless communication according to an aspect of the present invention.
5 is a view showing an input impedance of a short range wireless communication antenna according to an aspect of the present invention.

An embodiment of an antenna for short range wireless communication and an RFID reader including the same according to the present invention will be described in detail with reference to the accompanying drawings. In describing the accompanying drawings, the same or corresponding components are given the same reference numerals. Duplicate explanations will be omitted.

1 is a diagram schematically showing a configuration of an embodiment of a short-range wireless communication antenna 100 according to an aspect of the present invention.

According to this embodiment, as shown in Figure 1, the signal supply unit 110 for supplying the input signal to the antenna, the balun unit 120 for generating a balanced signal by phase-shifting the supplied signal, the resonance signal An antenna 100 for short range wireless communication including a resonator 130, and a load impedance 140 for suppressing and banding radiation of a resonance signal are provided.

As described above, according to the present exemplary embodiment, the signal supply unit 110, the balun unit 120, the resonator unit 130, and the load impedance 140 are connected so that signals input to the signal supply unit 110 are sequentially transferred to each component. As a result of the transmission, a uniform magnetic field in which no shadow is generated may be formed.

The antenna 100 for short range wireless communication may further include a dielectric layer (not shown). A signal supply line 110 may be formed on an upper surface of the dielectric layer, and a ground may be formed on the lower surface of the dielectric layer. The dielectric layer may be composed of a single printed circuit board (PCB).

One end of the signal supply unit 110 may be connected to an antenna port to receive a signal from a communication system, and the other end thereof may be connected to ground.

A signal is input to an antenna port formed at one end of the signal supply unit 110 and may generate a magnetic field and an electric field as the input signal is transmitted.

The signal supply unit 110 may be formed of any one of a straight feed line or a strip line to serve a feeding function, and the end of the signal supply unit 110 may be formed to be open.

The balloon unit 120 may be connected to the signal supply unit 110 and may convert a signal supplied from the signal supply unit 110 into a phase of 0 degrees and 180 degrees, which is a balanced signal.

The balloon unit 120 may be configured as any one of a coupling transmission line, a lumped element circuit, or a hybrid structure in which the coupling transmission line and the lumped element circuit are combined to function as a matching function.

Specifically, the balloon unit 120 may be implemented as a hybrid structure in which a marand balun using a coupled transmission line, an LC balun using a lumped element, a hybrid of the coupled transmission line and a lumped element, and the like.

The resonator 130 is connected to the balloon 120 and functions to resonate the phase-converted signal, and includes unit resonators 130a to 130n for resonating the phase-converted signal. The portions 130a to 130n may be formed in series.

The resonator 130 may generate a strong near field by generating resonance at an operating frequency.

Each unit resonator 130a to 130n may be formed of an inductor and a capacitor.

2A to 2D are diagrams illustrating an exemplary embodiment of the unit resonator units 130a to 130n of the short range wireless communication antenna 100 according to an aspect of the present invention.

For example, as illustrated in FIGS. 2A to 2D, the unit resonators 130a to 130n may be formed of a spiral inductor, a chip capacitor, a meander line, a chip capacitor, or the like.

In addition, the unit resonators 130a to 130n may be arranged side by side in the direction of current flow a pair of resonant circuit consisting of one inductor and one capacitor, the unit resonators 130a to 130n is the size of the RFID reader or RFID A plurality of tags may be arranged in a longitudinal direction in which current flows according to the recognition area of the tag.

The load impedance 140 may be disposed between both ends of the resonator 130 to form a loop, and one end of the load impedance 140 may be connected to ground. Here, the ground may be formed of a structure using physical ground or using virtual ground in an equilibrium state.

The load impedance 140 may use any one of a resistor, an inductor, or a capacitor, or a combination thereof.

3 is a view showing a radiation pattern according to an embodiment of the magnetic field formed around the antenna for short-range wireless communication according to an aspect of the present invention, Figure 4 is a radiation of a far field magnetic field of the antenna for short-range wireless communication according to an aspect of the present invention 5 is a diagram illustrating a pattern, and FIG. 5 is a diagram illustrating an input impedance of an antenna for short range wireless communication according to an aspect of the present invention.

When the physical length of a conventional signal supply unit is long, shaded points are generated at intervals of λ / 2 (where λ represents an effective wavelength) according to a wavelength of an applied signal. Is located near the signal supply, the RFID reader may not recognize the RFID tag.

On the other hand, according to the exemplary embodiment of the present invention, the magnetic field radiation pattern of the antenna for short range wireless communication in which three unit resonators are connected in series may be formed in a uniform shape in which no shade is generated.

The antenna for short-range wireless communication of the present invention is for short-range wireless communication. Referring to the experimental data of a far field magnetic field radiation pattern, as shown in FIG. You can see that.

In addition, the input impedance of the antenna for short-range wireless communication according to an aspect of the present invention, as shown in Figure 5, it can be seen that the impedance bandwidth is increased by approximately three times as compared to the case where the conventional signal supply unit at f. .

That is, according to the embodiment of the present invention, it can be seen that it is designed to maintain 50 ohms over a wide frequency range.

According to another embodiment of the present invention, an RFID reader including a receiving unit for receiving information from an RFID tag attached to an article through an antenna for short range wireless communication.

The RFID reader antenna may include a signal supply part, a balloon part, a resonator part, and a load impedance, and may further include a dielectric layer having a signal supply part, a balloon part, a resonator part, and a load impedance.

The signal supply part is connected to the antenna port at one end and the other end is connected to the ground and supplies the signal input to the antenna port, and the balun part is connected to the signal supply part and converts the signal supplied from the signal supply part into a balanced signal 0 degree and 180 degree phase can do.

The resonator may be connected to the balloon and resonate the phase-converted signal, and may include a plurality of unit resonators.

Here, the plurality of unit resonators are arranged to be connected in series in a current flow direction, and the number of unit resonators may be variously adjusted according to the size of the reader.

The RFID reader according to the present invention includes an antenna composed of a plurality of unit resonators, and thus the magnetic field distribution of the antenna may be uniformly formed without a shaded portion, thereby reducing the influence of the number of tagged articles.

As described above, according to the present invention, the RFID reader antenna may include a plurality of unit resonators connected in series to increase impedance bandwidth, and may have a constant tag recognition rate regardless of the number of articles placed on the RFID reader antenna and the number of tags attached to the article. Can be obtained.

Therefore, by using the frequency of the UHF band in the place where the goods are loaded, not only can the recognition speed and recognition rate of the RFID tag be increased at a short distance, but also the status of each item can be accurately managed without being affected by the quantity of the goods. .

As mentioned above, although an embodiment of the present invention has been described, those of ordinary skill in the art may add, change, delete or add components within the scope not departing from the spirit of the present invention described in the claims. The present invention may be modified and changed in various ways, etc., which will also be included within the scope of the invention.

100: antenna for short range wireless communication
110: signal supply
120: balloon
130: resonator
130a ~ 130n: unit resonance
140: load impedance

Claims (11)

A signal supply unit having one end connected to the antenna port and the other end connected to ground and supplying a signal input to the antenna port;
A balun unit connected to the signal supply unit and converting a signal supplied from the signal supply unit into a balanced signal having a phase of 0 degrees and 180 degrees;
A resonator configured to resonate the balanced signal converted by the balun; And
And a load impedance disposed between both ends of the resonator to form a loop.
The method of claim 1,
The signal supply unit is a short range wireless communication antenna, characterized in that formed in any one of a feed line or strip line of a straight form.
The method of claim 1,
The balun is a short-range wireless communication antenna, characterized in that any one of a combination transmission line, a lumped element circuit or a hybrid structure combining the combined transmission line and the lumped element circuit. The method of claim 1,
The resonator unit includes a unit resonator unit for resonating the balanced signal converted by the balun unit, a plurality of unit resonator antenna for short range wireless communication, characterized in that formed in the form connected in series.
The method of claim 4, wherein
And the unit resonator includes a spiral inductor, a chip capacitor, or a strip line, and a chip capacitor.
The method of claim 4, wherein
And a pair of resonant circuits including one inductor and one capacitor are disposed side by side in a direction in which current flows.
The method of claim 4, wherein
And a plurality of unit resonators are disposed in a longitudinal direction in which current flows.
The method of claim 1,
The load impedance is a short-range wireless communication antenna, characterized in that consisting of a resistor.
The method of claim 1,
The load impedance is a short-range wireless communication antenna, characterized in that one end is connected to the ground.
The method of claim 1,
And a dielectric layer, wherein the signal supply line is formed on an upper surface of the dielectric layer and the ground is formed on a lower surface of the dielectric layer.
The antenna for short range wireless communication of any one of Claims 1-10; And
And a receiver configured to receive information from an RFID tag attached to an article through the antenna.

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