KR101459768B1 - Antenna - Google Patents

Abstract

An antenna according to an embodiment includes a ground layer; A dielectric layer formed on the ground layer; A first conductor layer formed on the dielectric layer and having a slot formed therein; And a second conductor layer formed on the dielectric layer and spaced apart from the first conductor layer and formed in the slot.

According to the embodiment, the conductor layer, the shorting pin, and the ground layer have a PIFA structure, and the antenna gain can be improved and the transmission / reception efficiency can be improved by using the CPW feeding method. In addition, since the antenna can be secured in a small size and a wide ground plane can be secured, it is possible to improve the transmission / reception performance of the antenna, easily mount the antenna in a device having a limited layout space such as a tag, have.

Antenna, slot, conductor layer, dielectric layer, shorting pin, ground layer, CPW

Description

Antenna {Antenna}

An embodiment relates to an antenna.

An antenna is a device that converts an electric signal expressed by a voltage / current and an electromagnetic wave expressed by an electric field / a magnetic field, and interchanges the change of the electromagnetic field outside the antenna and the electrical signal on the wire inside the antenna.

RFID (Radio Frequency Identification) transceiver is a device that recognizes or records information held by a tag using a radio frequency in a non-contact manner. By using this device, it is possible to recognize, track, and manage tagged objects or persons .

The RFID transceiver has a unique identification information and includes a tag (Tag or Transponder) attached to an object or an animal, and a reader (Reader or Interrogator) that reads or records the identification information held by the tag.

Especially, the tags that are based on mobility have a limitation on the size, so there are many difficulties in designing the antennas.

For example, a dipole-type tag antenna is often used as a film-type antenna on which a conductor is printed. When such a tag antenna is attached to a ground plane, it becomes short-circuited and can not function as an antenna.

Also, for the conjugate matching with the tag chip having the capacitive impedance, the tag antenna must have an inductive impedance, but it is difficult to realize it by the structure of the film tag antenna.

Accordingly, the tag antenna must be manufactured in various sizes and shapes in accordance with the type of the tag chip product, so that the production efficiency is lowered and mass production becomes difficult.

At present, the tag antenna has improved the grounding structure and the ground plane has been developed as an integral product. However, since it is necessary to secure a certain height in order to avoid the short-circuit state and the price is high, The production of the tag product of the present invention is limited.

Embodiments provide an antenna capable of maximizing an antenna gain by controlling energy flow of a radiated signal, ensuring a small size and a wide ground plane, improving transmission / reception performance, facilitating impedance control, and attaching to a metal surface.

An antenna according to an embodiment includes a ground layer; A dielectric layer formed on the ground layer; A first conductor layer formed on the dielectric layer and having a slot formed therein; And a second conductor layer formed on the dielectric layer and spaced apart from the first conductor layer and formed in the slot.

According to the embodiment, the following effects can be obtained.

First, the antenna gain can be improved and the transmission / reception efficiency can be improved by using a planar inverted-F antenna (PIFA) structure and a coplanar waveguide (CPW) feeding method.

Second, since the antenna can be secured in a small size and a wide ground plane can be secured, it is possible to improve the transmission / reception performance of the antenna, easily mount the antenna in a device having a limited layout space such as a tag, have.

Third, since the impedance of the antenna can be adjusted by using the shorting pin, it is possible to match various impedances of the tag chip with the single antenna product.

Fourth, since the PIFA structure can be manufactured in the form of a printed board that can be easily processed, it is possible to expand the field of use of the antenna, to mass-produce it, and to lower the production cost.

Fifth, by using the antenna according to the embodiment, a small and inexpensive tag product can be manufactured.

The antenna according to the embodiment will be described in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view illustrating a structure of an antenna according to an embodiment of the present invention, and FIG. 2 is a side cross-sectional view illustrating a cut surface taken along the line A-A 'of the antenna shown in FIG.

1 and 2, an antenna according to an embodiment includes a first conductor layer 112, a second conductor layer 114, a dielectric layer 120, a ground layer 130, a first shorting pin 118, And a second shorting pin (116).

A chip element 140 is positioned between the first conductor layer 112 and the second conductor layer 114 and the chip element 140 is electrically connected to the first conductor layer 112) and the second conductor layer, respectively.

The antenna according to the embodiment can be used in various RF communication systems, but in the embodiment, it is exemplified that it is used in an RFID (Radio Frequency IDentification) tag using a frequency of about 900 MHz band.

A dielectric layer 120 is formed on the ground layer 130 and the first conductor layer 112 and the second conductor layer 114 are formed on the dielectric layer 120.

The first conductor layer 112 and the second conductor layer 114 are made of a metal such as copper and the first conductor layer 112 has a slot S formed therein.

Although the first conductor layer 112 is formed on the entire surface of the dielectric layer 120 and has a rectangular shape, the first conductor layer 112 may be formed in a part of the dielectric layer 120 and may have various shapes.

The second conductor layer 114 is formed in the slot S, spaced apart from the first conductor layer 112.

In an embodiment, the slot S and the second conductor layer 114 may also take various forms, and are illustrated as having a square shape in the embodiment.

The mutually opposing surfaces of the second conductor layer 114 may be formed to have the same distance as the first conductor layer 112.

That is, the distance between the top and bottom surfaces of the second conductor layer 114 and the first conductor layer 112 are the same, and the distance between the left and right surfaces of the second conductor layer 114 and the first conductor layer 112, May be formed to have the same length.

The distance between the left and right sides of the second conductor layer 114 and the first conductor layer 112 is greater than the distance between the top and bottom surfaces of the second conductor layer 114 and the first conductor layer 112 However, the spacing distance can be adjusted according to the radiation pattern.

The first conductor layer 112 and the second conductor layer 114 having such a structure are operated by a CPW (Coplanar Waveguide) method.

The dielectric layer 120 may have a square structure such as a square or a rectangle in order to efficiently radiate an RF signal and may be formed of a dielectric substrate such as FR-4 or an insulator such as an insulating film.

When the dielectric layer 120 is formed of a dielectric substrate, a copper foil is formed on the substrate surface and the copper foil is etched to form the first conductor layer 112, the second conductor layer 114, and the ground layer 130 And the capacitive reactance of the antenna can be adjusted according to the permittivity of the substrate (for example, 3.5 to 4.7).

When the dielectric layer 120 is formed using an insulating film, it is preferable to use an insulating film such as a PET film, a polyimide (PI), a polyethylene naphthalate (PEN), a polyvinyl chloride (PVC), a paper, an acetate, a polyester, The first conductor layer 112, the second conductor layer 114, the ground layer 130, and the like may be used as the first conductor layer 112. The first conductor layer 112, the second conductor layer 114, and the ground layer 130 may be made of a material such as polypropylene, polypropylene having calcium carbonate, acrylonitrile butadiene styrene May be formed by applying a conductive material to the surface of the insulating film.

In an embodiment, the dielectric layer 120 may be formed of a FR4 substrate through a printed circuit board (PCB) process.

The first conductor layer 112 and the second conductor layer 114 serve as a line through which a current from the chip device 114 or a current due to an energy signal in the atmospheric air flows, Causing a capacitance component.

The size, shape and position of the slot S and the distance between the first conductor layer 112 and the second conductor layer 114 can be adjusted according to the characteristic impedance of the antenna.

The chip element 140 is die-bonded to the dielectric layer 120 exposed through the slot S and the first conductor layer 112 and the second conductor layer 114 ). At this time, the chip device 160 may be positioned at an intermediate portion of the slot S in consideration of current flow.

The chip device 140 may include an RF transceiver circuit, a control logic, a memory, and the like, and transmits and receives RF frequencies through the first conductor layer 112 and the second conductor layer 114.

In addition, since the chip device 140 is connected to the first conductor layer 112 and the second conductor layer 114, there is no directionality with respect to electrical polarity, and the chip device 140 operates without polarity A feed current can flow in both directions of the first conductor layer 112 and the second conductor layer 114.

The connection member 142 may be formed using a conductive pad or a lead and the electrical connection between the chip element 140 and the first and second conductor layers 112, Chip bonding, wire bonding, or the like.

In addition, the antenna according to the embodiment can be used for an RFID tag or an RFID reader according to the type of the chip device 140, and can be manufactured in various sizes according to the use environment.

For example, the size of the antenna according to the embodiment may be about 140 mm x 20 mm and the thickness about 1 mm, and the first conductor layer 112 and the second conductor layer 114 may have a thickness of about 0.5 mm As shown in FIG.

The first shorting pin 118 extends from the first conductor layer 112 to the ground layer 130 to electrically connect the first conductor layer 112 and the ground layer 130.

The first shorting pins 118 are arranged along one end of the first conductor layer 112. The number and the interval of the first shorting pins 118 may be adjusted according to the impedance characteristics of the antenna.

For example, assuming that the impedance of the antenna according to the embodiment is "16 + j117 ?, " the first shorting pins 118 are provided in a number of about ten, and the first shorting pins 118 are formed on the entire one end of the first conductor layer 112 They can be arranged at regular intervals.

The first conductive layer 112, the first shorting pin 118 and the grounding layer 130 have a modified PIFA (Planar Inverted-F Antenna) structure and have a band width and reflectance at a resonant frequency The size of the first conductor layer 112 and the ground layer 130, and the number and position of the first shorting pins 118 can be adjusted according to factors such as loss, return loss, and impedance matching efficiency.

The antenna according to the embodiment using the vertical PIFA structure has an advantage of being easy to deform and work.

The second shorting pin 116 penetrates from the second conductor layer 114 to the grounding layer 130 to electrically connect the second conductor layer 114 and the grounding layer 130.

Since the second shorting pin 116 does not participate in the PIFA structure unlike the first shorting pin 118, the number and position of the second shorting pin 116 are relatively free from deformation.

Also, the first shorting pin 118 and the second shorting pin 116 may be formed through a via hole process.

As such, the first shorting pin 118 and the second shorting pin 116 affect the current distribution of the first conductor layer 112 and the second conductor layer 114, The antenna element 112 and the second conductor layer 114 are strengthened by the first shorting pin 118 and the second shorting pin 116 to improve the antenna performance.

3 is a diagram illustrating a form of a radiation pattern when a signal is resonated in the antenna according to the embodiment.

The radiation pattern shown in FIG. 3 is obtained by vertically positioning the antenna according to the embodiment and sequentially moving the angle of the signal source in the axial direction from 0 degrees to 90 degrees. It can be observed that the gain is evenly enhanced.

The areas displayed on the radiation pattern represent the difference in power gain.

For reference, the frequency efficiency at the measurement was 0.1926 and the gain (dB) was measured at 3.334 dB in the S parameter (S1.1; meaning the input and output ports are equal).

The general PIFA type antenna does not have a uniform radiation pattern in all directions as in the embodiment, and the gain is only about 3dBi.

However, the overall gain of the antenna according to the embodiment is more than 5 dBi, which is more than 2 dBi higher than that of the general PIFA type antenna.

FIG. 4 is a graph showing a band of a signal resonated by the antenna according to the embodiment, and FIG. 5 is a Smith chart showing the impedance of the antenna according to the embodiment.

In the graph of FIG. 4, the y-axis represents the power value (dB) and the x-axis represents the frequency band (Hz).

Referring to FIG. 4, a frequency band F of a frequency signal resonated by the first conductor layer 112 and the second conductor layer 114 is measured. When resonance occurs in the range of about 0.90239 GHz to 0.91933 GHz, (BW) of about 0.01694 GHz.

The resonance frequency band of the antenna according to this embodiment is a value including both the North American type RFID (902 to 930 MHz) and the Korean type RFID (908.5 to 915 MHz) frequency band.

Therefore, by using the antenna according to the embodiment, it is possible to satisfy a plurality of frequency bands allocated to the RFID communication channel, and thus it can be utilized in an RFID transmission / reception system such as an RFID tag or an RFID reader used for various purposes.

5, the impedance according to each frequency band of the antenna according to the embodiment is displayed. The display point "E" is a case where frequency resonance hardly occurs, and an impedance of about 0.006203-j3.062e-015 Numbers are shown.

The display point "C" in the band of about 909 MHz and the display point "D" in the band of about 915 MHz have impedance values of (7.525 + j89.75)?, (31.65 + j167.6)?, The design of the slot S, the first shorting pin 118, the second shorting pin 116, etc. according to the 900 MHz band standard is satisfied.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications other than those described above are possible. For example, each component specifically shown in the embodiments of the present invention can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

1 is a perspective view illustrating a structure of an antenna according to an embodiment.

FIG. 2 is a side cross-sectional view showing a cut surface taken along the line A-A 'of the antenna shown in FIG. 1; FIG.

3 is a diagram illustrating a form of a radiation pattern when a signal is resonated in an antenna according to an embodiment.

FIG. 4 is a graph showing a band of a signal resonated in the antenna according to the embodiment; FIG.

5 is a Smith chart showing an impedance of an antenna according to an embodiment.

Claims (10)

A ground layer; A dielectric layer formed on the ground layer; A first conductor layer formed on the dielectric layer and having a slot formed therein; A second conductor layer formed on the dielectric layer and spaced apart from the first conductor layer and formed in the slot; And And a second shorting pin penetrating from the second conductor layer to the ground layer and electrically connecting the second conductor layer and the ground layer. The method according to claim 1, Wherein the slot and the second conductor layer are in a rectangular shape, And the mutually opposing surfaces of the second conductor layers have the same distance as the first conductor layer. The method according to claim 1, And a first shorting pin penetrating from the first conductor layer to the grounding layer and electrically connecting the first conductor layer and the grounding layer. The connector of claim 3, wherein the first shorting pin And arranged along one end of the first conductor layer. delete The method according to claim 1, A chip element is provided in the slot, and the chip element is electrically connected to the first conductor layer and the second conductor layer. The connector of claim 3, wherein the first shorting pin An antenna that forms a via hole structure. The connector of claim 1, wherein the second shorting pin An antenna that forms a via hole structure. The method of claim 1, wherein the dielectric layer An antenna comprising an FR4 substrate. The connector of claim 3, wherein the first shorting pin And the number and spacing are adjusted according to the impedance.

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