KR20110020617A - Circularly polarized antenna for uhf band rfid reader - Google Patents

Circularly polarized antenna for uhf band rfid reader Download PDF

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Publication number
KR20110020617A
KR20110020617A KR1020090078323A KR20090078323A KR20110020617A KR 20110020617 A KR20110020617 A KR 20110020617A KR 1020090078323 A KR1020090078323 A KR 1020090078323A KR 20090078323 A KR20090078323 A KR 20090078323A KR 20110020617 A KR20110020617 A KR 20110020617A
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KR
South Korea
Prior art keywords
base substrate
antenna
rfid reader
circular polarization
dielectric substrate
Prior art date
Application number
KR1020090078323A
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Korean (ko)
Inventor
서장원
Original Assignee
(주)바소콤
서장원
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Publication date
Application filed by (주)바소콤, 서장원 filed Critical (주)바소콤
Priority to KR1020090078323A priority Critical patent/KR20110020617A/en
Publication of KR20110020617A publication Critical patent/KR20110020617A/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
    • H01Q1/2225—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/44—Details of, or arrangements associated with, antennas using equipment having another main function to serve additionally as an antenna, e.g. means for giving an antenna an aesthetic aspect
    • H01Q1/46—Electric supply lines or communication lines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/48—Earthing means; Earth screens; Counterpoises
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/50—Feeding or matching arrangements for broad-band or multi-band operation

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  • Details Of Aerials (AREA)

Abstract

PURPOSE: A circular polarization antenna for the UHF RF ID reader is provided to offer an advantage of reducing the reflection loss while minimizing the size. CONSTITUTION: A circular polarization antenna for the UHF RF ID reader comprises a base substrate(110), a dielectric substrate(120), and a radiation plate. The base substrate is made of the aluminium alloy. A ground part(122) formed on the dielectric substrate is connected to the conductive material.

Description

Circularly polarized antenna for UHF band RFID reader

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circularly polarized antenna for a UEF RFID reader, and more particularly, to a circularly polarized antenna for a UEF RFID reader which can improve reception sensitivity.

RF ID (RFID) is able to transmit more information than the existing barcode system, and is being developed to be applied to new applications such as ubiquitous sensor networks.

In most countries, frequencies of 13.56Mhz (HF band), 860 to 960MHz (UHF band), and 2.4GHz (ISM band) are used in most countries.

However, the RFID of the HF band has a disadvantage in that the antenna recognition area is very narrow by using the magnetic field coupling method, and the RFID of the ISM band is sensitive to the surrounding environment and has the disadvantage that the performance of the entire RFID system is variable. On the other hand, the UHF band has the highest recognition rate and recognition distance of passive tags, and can recognize a large number of tags at high speed simultaneously using the electromagnetic radiation method. It is also known as the most popular band of RFID because it is very stable in the surrounding environment and low-cost production of tags and tag chips is possible. At present, the UHF band (908.5 ~ 914MHz) is allocated a frequency for RFID use, and research and development is in progress in various fields.

In the RFID system of the UHF band, the role of the antenna is important in the mutual wireless electromagnetic method of the reader and the tag. Especially in passive RFID which receives the power of tag from reader, the characteristic of antenna is one of important factors in determining communication recognition distance between reader and tag. Therefore, the RFID reader antenna characteristic should have little reflection loss in the operating frequency band and be designed to have good circular polarization. In addition, the reader antenna should have a high radiated power to enable remote recognition and multi-tag recognition, and the size of the antenna should have a small cross-sectional area in order to effectively use a given space.

SUMMARY OF THE INVENTION The present invention has been made to solve the above requirements, and an object thereof is to provide a circularly polarized antenna for a UEF RFID reader which can reduce the size and reduce the reflection loss.

In order to achieve the above object, a circular polarization antenna for a UEF RFID reader according to the present invention includes a base substrate; A dielectric substrate coupled to the base substrate in parallel with the base substrate; A feed line formed of a conductive material on the dielectric substrate for impedance matching; A phase conversion unit connected to one end of the power supply line to generate a signal having a phase difference of 90 ° through first and second connection ends; A first strip line connected to the first connection end and bent in multiple stages; A second strip line connected to the second connection end and bent in multiple stages; A ground part connected to the ground end of the phase shift part; And a radiating plate installed below the base substrate in a plate shape and connected through connection bars extending from the ends of the first and second strip lines through the base substrate.

Preferably, the base substrate is formed of an aluminum material and connected to a ground portion formed on the dielectric substrate.

The circular polarization antenna for the UEF RFID reader according to the present invention provides an advantage of reducing the return loss while miniaturizing the size.

Hereinafter, with reference to the accompanying drawings will be described in more detail a circular polarization antenna for a UEF RFID reader according to a preferred embodiment of the present invention.

1 is a plan view showing a circular polarization antenna for a UEF ID reader according to the present invention, Figure 2 is a side view of the circular polarization antenna for a UEF ID reader of Figure 1, Figure 3 is a Ue of FIG. This is a block diagram of a signal transmission system of a circular polarization antenna for a chief RFID reader.

1 to 3, a circular polarization antenna 100 for a UEF RFID reader includes a base substrate 110, a dielectric substrate 120, and a radiation plate 130.

The base substrate 110 is formed in a rectangular shape.

The base substrate 110 is formed of an aluminum material, and is preferably connected to the ground portion 122 formed on the dielectric substrate 120 using a conductive material.

The base substrate 110 is installed between the radiating plate 130 and the dielectric substrate 120 to be described later to bind the radiating plate 130 and the dielectric substrate 120 to be mutually supported, and to extend the ground portion 122. Function.

The dielectric substrate 120 is coupled to the base substrate 110 in parallel with the base substrate 110 to be spaced apart from the base substrate 110 on the base substrate 110. Reference numeral 112 is a coupling member for coupling the base substrate 110 and the dielectric substrate 120 to be spaced apart from each other, a screw of a conductive metal material may be applied.

The dielectric substrate 120 applies to a dielectric material having a dielectric constant ε r in the range of 4 to 5. Preferably, the dielectric substrate 120 applies a FR-4 epoxy substrate having a dielectric constant of 4.3.

The feed line 124 is formed to be bent from the conductive material in the cavity 123 formed to expose the dielectric substrate 110 inside the ground portion 122 so as to have 50 kHz for impedance matching to the dielectric substrate 120.

The phase shifter 125 is connected to one end of the power supply line 124 so as to output a signal having a phase difference of 90 ° through the first and second connection ends 125a and 125b, respectively.

As the phase shifter 125, a hybrid coupler is preferably applied.

The ground plane 124 is formed of a conductive material under the dielectric substrate 120 and is connected to the ground terminal 125c of the phase shifter 125.

The first strip line 126 is connected to the first connection end 125a and is bent and extended in multiple stages.

The second strip line 127 is connected to the second connection end 125b and is bent and extended in multiple stages.

Here, the first and second strip lines 126 and 127 each have a length of half wavelength λ / 2 of the center wavelength λ and are formed of a conductive material in a bent pattern so as to form circular polarizations. Is preferred. In the illustrated example, the first and second strip lines 126 and 127 are bent to have a polarization characteristic of left turn circular polarization (LHCP).

The radiating plate 130 is formed of a conductive material in the form of a square plate to form the base substrate 110 from the ends 126a and 127a of the first and second strip lines 126 and 127 under the base substrate 110. It is connected through connecting bars 128 and 129 extending through. The connection bars 128 and 129 may be formed of a conductive material, but may be formed of a diameter which does not come into contact with the through holes formed in the base substrate 110.

The UHF band circular polarization antenna 100 structure for the UHF reader was manufactured to have an impedance of 50 Ω in the UHF band, and each strip 124, 126, 127 has a width of 2 mm and a length of the feed line 124. ) And 4 cm, and the first and second strip lines 126 and 127 are each 18 cm. In addition, the dielectric constant of the dielectric substrate 120 was 4.3, 1.0mm thick FR-4 epoxy substrate was used, 11cm in width, 11cm in length was made of a square. The radiation plate 130 was manufactured to be 13.4 cm in width and length, respectively.

The measurement result of the return loss (Return Loss) of the manufactured UHF RFID reader antenna 100 is as shown in Figure 4, it was confirmed that the return loss is reduced by obtaining the measurement data values as shown in Table 1 below.

frequency Return loss 908.5 MHz -33.355 dB 911.9 MHz -38.168 dB 914 MHz -45.529 dB

In addition, the -10dB return loss bandwidth is 670MHz-940MHz (270MHz: 33.5%) and has a wideband characteristic, and the ratio ratio is 1.2dB at 911MHz, the center frequency band of the UHF RFID reader.

On the other hand, the impedance matching parameter measurement results of the fabricated antenna are shown in FIG. 5, and the measured values as shown in Table 2 below were obtained.

frequency impedance 908.5 MHz 50.09Ω 911.9 MHz 50.48Ω 914 MHz 50.72Ω

Next, in order to examine the characteristics of the radiation pattern of the fabricated antenna, the fabricated antenna is rotated in the horizontal and vertical directions with a distance of 2.36m with respect to the antenna fabricated with respect to the standard antenna. Was measured.

The gain data of the radiation pattern measured in an environment in which the standard antenna is placed horizontally and the antenna fabricated in front is shown in FIG. 6, and the gain is 5.59 dBi. In addition, the gain data of the radiation pattern measured in an environment in which the standard antenna is placed vertically and the antenna which is manufactured in front is shown in FIG. 7, and the gain is 6.09 dBi. 8 is a gain data of a radiation pattern measured in an environment in which the antenna manufactured with the standard antenna horizontally rotated by 90 degrees. The gain value is 6.19 dBi. FIG. 9 shows the antenna manufactured with the standard antenna vertically. It is the gain data of the radiation pattern measured in the environment rotated 90 degrees and the gain value is 5.09dBi.

On the other hand, the VSWR of the manufactured antenna was excellent as 1.037.

As described above, the antenna has a high antenna gain while miniaturizing its size, and it is confirmed that the antenna provides a recognition distance of about 4 m as a result of measuring the tag recognition distance accordingly.

1 is a plan view showing a circular polarization antenna for a UEF RFID reader according to the present invention,

Figure 2 is a side view of the circular polarization antenna for the UEF RFID reader of Figure 1,

FIG. 3 is a block diagram of a signal transmission system of a circular polarization antenna for a UEF RFID reader of FIG. 1,

FIG. 4 is a graph measuring return loss of an antenna manufactured with the structure of FIG. 1;

FIG. 5 is a graph measuring matching impedance of an antenna manufactured with the structure of FIG. 1. FIG.

6 to 9 are views showing the results measured for the radiation pattern of the antenna manufactured in the structure of FIG.

Claims (2)

In the circular polarization antenna for the UEF RFID reader, A base substrate; A dielectric substrate coupled to the base substrate in parallel with the base substrate; A feed line formed of a conductive material on the dielectric substrate for impedance matching; A phase conversion unit connected to one end of the power supply line to generate a signal having a phase difference of 90 ° through first and second connection ends; A first strip line connected to the first connection end and bent in multiple stages; A second strip line connected to the second connection end and bent in multiple stages; A ground part connected to the ground end of the phase shift part; UEP RFID reader having a plate shape installed below the base substrate and connected through a connecting bar extending through the base substrate from the ends of the first and second strip lines. Circularly polarized antenna. 2. The circular polarization antenna of claim 1, wherein the base substrate is formed of an aluminum material and is connected to a ground portion formed on the dielectric substrate.
KR1020090078323A 2009-08-24 2009-08-24 Circularly polarized antenna for uhf band rfid reader KR20110020617A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020090078323A KR20110020617A (en) 2009-08-24 2009-08-24 Circularly polarized antenna for uhf band rfid reader

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105098339A (en) * 2014-05-15 2015-11-25 中国科学院微电子研究所 UHF frequency range RFID reader-writer antenna and system
US9887464B2 (en) 2015-10-22 2018-02-06 Ajou University Industry-Academic Cooperation Foundation Compact dipole antenna for RFID tag

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105098339A (en) * 2014-05-15 2015-11-25 中国科学院微电子研究所 UHF frequency range RFID reader-writer antenna and system
CN105098339B (en) * 2014-05-15 2018-06-01 中国科学院微电子研究所 A kind of uhf band RFID reader antenna and system
US9887464B2 (en) 2015-10-22 2018-02-06 Ajou University Industry-Academic Cooperation Foundation Compact dipole antenna for RFID tag

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