KR20070009062A - Polygonal helix antenna for rfid reader - Google Patents

Abstract

A polygonal helix antenna for an RFID reader is provided to adjust a reflective loss characteristic and an operational frequency of a wide band by adjusting an electrical length according to a frequency in a limited antenna size. A polygonal helix antenna for an RFID reader includes a path section. The path section is matched with a feeding line(11), and is operated as an antenna of a predetermined frequency band. The path section forms a polygonal shape when the path section is viewed from a radiation plane in parallel with a ground plane(14). The antenna section has at least one bent shape to the ground plane or a vertical direction. The antenna section comprises a single antenna path of a polygonal shape when the antenna section is viewed from the radiation plane.

Description

Polygonal Helix Antenna for RFID Reader

1 is a perspective view of a single-layer polygonal helix antenna for a UHF band RFID reader according to a first embodiment of the present invention.

FIG. 2 is a side view of the antenna shown in FIG. 1 as viewed in the direction of the arrow. FIG.

FIG. 3 is a plan view of the antenna shown in FIG. 1 from above, wherein the antenna lines form a single polygonal structure.

FIG. 4 is a development view in which the polygonal structure of the antenna shown in FIG. 1 is unfolded into a planar structure.

5 is a perspective view of a multi-layered polygonal helix antenna for a UHF band RFID reader according to a second embodiment of the present invention.

FIG. 6 is a side view of the antenna shown in FIG. 5 as viewed in the direction of the arrow. FIG.

FIG. 7 is a plan view of the antenna shown in FIG. 5 from above, wherein the antenna lines form a two-ply polygonal structure.

FIG. 8 is a development view in which the polygonal structure of the antenna shown in FIG. 5 is unfolded into a planar structure.

9 is an enlarged view of the dotted line of FIGS. 4 and 8, and the shape of the line is increased or decreased by the pitch angles θ ₁ , θ ₂ , θ ₃ , θ ₄ , θ ₅ , and θ ₆ . Seems to be made.

10 is a graph showing the radiation gain according to the size of the single-layer structure antenna and the multi-layer structure optimization antenna having two layers.

11 is a graph of return loss characteristic according to the frequency of a multi-ply antenna;

12 is an axial ratio graph showing circular polarization characteristics according to the frequency of an antenna in all directions (θ = 0 °) of a multi-ply antenna.

FIG. 13 is a single polarized gain graph of 912 MHz in all directions (θ = 0 °) of a multi-ply antenna; FIG.

FIG. 14 is a graph of antenna radiation gain of 912 MHz at Φ = 0 ° of a multi-ply antenna. FIG.

FIG. 15 is a graph of antenna radiation gain of 912 MHz at Φ = 90 ° of a multi-ply antenna; FIG.

16A to 16D show the unfolded forms of the multi-ply structure antennas having pitch angles of 1, 2, 3, and 4, respectively.

17 is a graph of return loss characteristics when the number of pitch angles of a multiple-ply antenna is 14, 16, and 19. FIG.

FIG. 18 is a graph of circular polarization axial ratio when the number of pitch angles of a multi-ply antenna is 14, 16, and 19. FIG.

** Description of the symbols for the main parts of the drawings **

10: antenna of single layer polygonal helix structure

11: antenna feeder coaxial line

12: dielectric substrate

13: microstrip line (external antenna line)

14: ground plane

31: internal angle of the external antenna of the polygon structure

41: Print shape of the external antenna line

42: some sections of the external antenna line

43: 1 / 4-wave matcher track

50: two-layered polygonal helix structure

51, 81: connection line between the external antenna line and the internal antenna line

52: Microstrip line (internal antenna line)

71: internal angle of the internal antenna of the polygonal structure

82: print pattern of internal antenna line

91: pitch angle of the antenna

The present invention relates to an antenna, and more particularly, to an antenna for a UHF band (860 MHz to 960 MHz) Radio Frequency Identification (RFID) reader.

RFID is gaining in importance as one of the major means for realizing the ubiquitous computing concept. According to the recent research trend, a lot of researches are conducted worldwide in the UHF band having excellent propagation characteristics.

The RFID device can be largely classified into a tag storing recognition information and a reader reading the information. The tag and reader use the antennas attached to each other to transmit information through the electromagnetic wave. RFID is realized in several bands, such as the HF band (13.56 MHz), the UHF band (860 MHz to 960 MHz), and the ISM band (2.4 GHz). However, the RFID of the HF band has a disadvantage that the antenna recognition area is very narrow by using the magnetic field coupling method. RFID in 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 best recognition rate and recognition distance of passive tags, and it has the advantage of recognizing a large number of tags at the same time using electromagnetic radiation. In addition, it is known to be the most popular band among RFID use bands because it is very stable in the surrounding environment and low-cost production of tags and tag chips is possible.

In the UHF band RFID system, the role of the antenna connecting the reader and the tag is important. In particular, passive RFID, which receives tag power through radio waves of the reader antenna, determines the communication efficiency of the system according to the characteristics of the reader antenna. An effective RFID reader antenna should have little return loss in the operating frequency band (VSWR <2) and be designed to have good circular polarization (Axial Ratio <3 dB). In addition, the reader antenna must have a high radiation gain and the radiation pattern required by the system to enable remote recognition and multi-tag recognition, and the size of the antenna must be small to efficiently use a given space.

At present, many antennas for transmitting / receiving circular polarization have been developed, but there is a side that is not suitable for use as an RFID reader antenna. It is necessary to develop a reader antenna for transmitting / receiving suitable for RFID and have an antenna characteristic that matches the reader antenna.

Conventional RFID reader antennas currently commercially available are patch antennas using microstrip. However, the patch antenna has a disadvantage in that the return loss bandwidth and the circular polarization bandwidth are narrow, and it is very difficult to control the antenna recognition area, which is an important characteristic of the reader antenna. That is, since the antenna radiation pattern which determines the antenna recognition area is radiated in the frontside direction of the patch in the case of a single patch type antenna, an array method is required to solve this problem. As another example, there are many types of helix antennas such as cylindrical, spherical, hemispherical, and quadrifilar helix, and generally emit high-quality circular polarization, but gain and return loss. Because of their advantages and disadvantages in terms of bandwidth, beam width, and ease of fabrication, a new type of antenna is required to design antennas for RFID readers.

The present invention has been made in view of the necessity set forth above, and an object thereof is to provide an antenna capable of transmitting / receiving irrespective of a radiation polarization of a tag having a high quality circular polarization characteristic.

Another object of the present invention is to provide an antenna having a high radiation gain to facilitate remote recognition of a tag.

In addition, another object of the present invention is to provide an antenna that can easily control the radiation pattern to satisfy the recognition area required by the system.

Furthermore, another object of the present invention is to provide an antenna having a structure capable of mass production at a low price.

Furthermore, an object of the present invention is to provide an antenna that can operate without return loss by matching with a reader system.

According to the present invention for achieving the above object, is matched with the feed line is operated as an antenna of a predetermined frequency band, the antenna line includes a line section forming a polygonal shape when viewed from the plane of radiation parallel to the ground plane, The antenna line is provided with an antenna having a polygonal helix structure having a shape bent at at least one point in a direction perpendicular to the ground plane.

According to a preferred configuration, the antenna line, when viewed in the radiation plane, consists of only one layer of polygonal antenna line, the antenna may be a single-layer polygonal helix structure. In addition, according to another preferred configuration, the antenna line, when viewed in the radiation plane, the antenna lines of different polygonal shape of different sizes overlap each other, the antenna may be a multi-polygon helix structure. In this case, the antenna line includes an external antenna line, at least one or more internal antenna lines, and a connection line connecting each antenna line to each other. As such, the antenna of the present invention may form a stacked structure therein to improve the remote recognition characteristics of the antenna. In particular, when using a laminated structure composed of an outer layer antenna and a plurality of stages repeated therein, the antenna structure of the inner stage shows high gain radiation characteristics. Furthermore, in the antenna of the present invention, the number of times the line is wound, the electrical length, and the antenna height are determined by the pitch angle and the antenna structure of the stage. As described above, the antenna of the present invention has an advantage in that the antenna radiation pattern can be easily adjusted by changing the stack structure and the pitch angle.

The antenna line is preferably made of a microstrip line which is printed on the surface of the dielectric substrate bent in a polygonal shape to form a polygon when viewed in the radiation plane. That is, the dielectric on which the antenna line is printed is folded in a polygonal shape so that the antenna main body line has a polygonal structure that appears to be folded when viewed in a direction parallel to the ground plane. By adjusting the angle and angle of the polygon, it is possible to control the rotational angular velocity of the current induced in the line, which makes it possible to have good circular polarization radiation characteristics. The dielectric substrate is preferably a substrate of a material that can be folded to maintain a polygonal tubular shape. Examples of such substrates include paper board materials. As such, in order to enable commercialization of the antenna of the present invention, the main body line of the antenna is implemented in a microstrip structure on a dielectric substrate which is inexpensive and easy to mass-produce, and the dielectric substrate may be folded into a polygonal structure.

In addition, the antenna line is preferably a structure having a negative pitch and a positive pitch by bending at multiple points in a direction perpendicular to the ground plane. The pitch angle is preferably set to a value such that the current phase induced in the line is constantly reduced so that traveling waves are formed in the line. That is, according to the structure of the antenna of the present invention, the pitch angle (pitch angle) of the antenna line can be repeated a number of times to increase and decrease, and has a structure that can change the change point of the pitch angle. Various changes in pitch angle provide a constant phase change, which is a current characteristic that appears when a current emits a circular polarization. The improved line freedom of the antenna of the present invention increases the total electrical length of the antenna line, thereby minimizing the size of the antenna, and adjusts to reduce the current phase induced in the line uniformly, thereby forming a traveling wave with easy circular polarization radiation. do.

Furthermore, in order to be used as an RFID reader antenna, the feed line has an impedance of 50 Ω, and the operating frequency of the antenna is preferably in the frequency band of 860 MHz to 960 MHz.

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

1-9 exemplarily show the structure of two representative sample antennas according to the present invention. 1 to 4, according to the first embodiment of the present invention, is a polygonal helix antenna having a single layer structure having an external antenna stage of a pentagon. The antenna 50 shown in FIGS. 5 to 8 is an example of a multi-ply antenna according to the second embodiment of the present invention. In particular, the antenna 50 shows a 2-ply antenna having a pentagonal external antenna stage and a pentagonal internal antenna stage. .

First, the structure of the polygonal helix antenna 10 having a single layer structure according to the first embodiment of the present invention will be described. 1 is a perspective view of this antenna 10, FIGS. 2 and 3 are side and top views, respectively, of the antenna shown in FIG. 1, and FIG. 4 is a development view showing a planar printing structure of the single-layer antenna of FIG. The illustrated antenna 10 is a sample antenna structure of a polygonal helix antenna, which is formed by printing a single line of the microstrip line 13 on the surface of the dielectric substrate 12. The start end of the microstrip line 13 is fed from a 50 Ω feed line coaxial line 11 to a ground plane 14 having a size of 20 cm x 20 cm, for example.

More specifically, the antenna 10 is configured as a microstrip line in the outer antenna portion 41 and has a broadband return loss bandwidth by a quarter-wave transformer 43. The dielectric substrate 12 may be made of a material such as a thick paper. The microstrip line 13 is implemented by printing on one surface of the dielectric substrate 12. The dielectric substrate 12 is installed along the ground plane 14 so as to form a polygonal tube shape by folding along a plurality of bend lines 42. Accordingly, the antenna 10 has a polygonal antenna shape when viewed from above as shown in FIG. 3.

In addition, referring to FIG. 4 and a partially enlarged view of FIG. 9, the microstrip line 13 of the antenna 10 divided by the bending line 42 is variously bent up and down at various points when viewed from the side. By taking the equation, a structure having a change in various pitch angles 91 (θ ₁ , θ ₂ , ..., θ ₆ ) is obtained. The polygon number of the polygonal structure formed by folding the dielectric substrate 12 on which the microstrip line 13 is printed and the internal angle 31 of the polygonal structure can be freely set, and an optimization technique such as Pareto Genetic Algorithm The optimal design value can be found by applying.

5 to 8 show a structure of a polygonal helix antenna 50 having a multi-ply structure according to a second embodiment of the present invention. FIGS. 5, 6, and 7 are perspective, side and top views, respectively, of the antenna. 8 is a development view showing a planar printing structure of the multi-layered antenna 50 of FIG. 5. The illustrated antenna 50 is a two-ply antenna, which is an example of a multi-ply structure.

In the two-ply polygonal helix antenna 50, the inner antenna part 82 is disposed inside the outer antenna part 41, and the striplines 13 and 52 of these two parts 41 and 82 are connected to each other. It is connected to the stripline (connecting line) 51 of the part 81 to form a two-ply antenna. The antenna is embodied in a microstrip line structure on the dielectric substrate 12 and is matched and fed from a feed line coaxial line 11 of 50 Ω to a ground plane 14 of 20 cm x 20 cm, for example. The antenna 50 has a structure in which the antenna 10 having the single-layer structure of the first embodiment is used as the outer end antenna part 41 and the inner end antenna part 82 is added therein, and the connecting parts 81 are connected to each other. can see.

More specifically, the antenna 50 is implemented with microstrip lines 13, 51, 52 printed on the dielectric substrate 12, which is inexpensive as the first embodiment. Thick paper can be used. For example, the microstrip lines 13, 51, and 52 are printed on one dielectric substrate 12 as shown in FIG. 8, and then the dielectric along several bend lines 42 (indicated by 'dotted lines' in FIG. 8). The substrate is folded to form a multi-layered tubular structure having a 2-ply structure as shown in FIG. 5. In this way, the microstrip lines 13, 51, and 52 are folded at points of the bend line 42 to form a double-layered polygonal antenna as shown in the plan view of FIG. 6, 8, and 9, antenna cross-sections divided by the bend lines 42 have various pitch angles 91 by variously bending the antenna lines in the vertical direction at various points. The quarter-wave matcher 43 of the outer antenna portion 41 has a wideband return loss bandwidth.

Although the antenna of the two-ply structure has been exemplarily illustrated in the drawings, the antenna according to the second exemplary embodiment may have a three-ply or more multi-ply structure with the number of internal antenna stages. Furthermore, the number and shape of the polygon structures of the quarter-wave matcher 43, the pitch angle 91 in the vertical direction, and the microstrip line formed by folding the dielectric substrate 12, and the inside of the polygon structure of the external antenna The angle 31 and the inner angle 71 of the polygonal structure of the inner stage antenna can be freely set. These factors can also be found by applying optimization techniques such as genetic algorithms.

Next, the main points to be considered in determining the detailed design parameters of the antenna of the present invention are largely the following three parts.

(1) feeder

The antenna of the present invention uses a quarter-wave matcher in the subsequent portion of the feeder to secure the broadband return loss bandwidth. In general, the helix antenna has a constant impedance of 100 to 200 Ω, thereby securing a wide bandwidth return loss bandwidth. However, in order to match the characteristic impedance of the feeder to 50Ω, a matcher is required. In the present invention, a quarter-wave matcher is used at a portion where the antenna line starts to lower the antenna main body impedance of 100 to 200Ω by 50Ω to match the feed impedance.

(2) pitch angle of antenna line

The antenna of the present invention has a structure capable of repeating the pitch angle increase and decrease of the line a plurality of times to change the circular polarization bandwidth of the line, and also changes the change point of the pitch angle. The pitch angle must be determined so that the current phase induced in the line is constantly reduced so that a traveling wave is formed in the line.

(3) Polygonal structure of antenna line

It is possible to adjust the rotational angular velocity of the induced current in the antenna line of the polygonal structure. The angular velocity of circular polarization is determined by the following equation and E ₁ (0, t) and E ₂ (0, t) represent the horizontal and vertical components of circular polarization when viewed from the front of the radiation.

As shown in the equation above, the rotational angular velocity is determined by the ratio of E ₁ (0, t) and E ₂ (0, t) over time. The antenna of the present invention can obtain a rotational angular velocity that is easy to circularly polarize radiation if the length of the line at each end is approximately an integer multiple of the wavelength, provided that the traveling wave is formed in the line.

The optimal design parameters of the antenna of the present invention can be determined using the optimization technique and the performance prediction simulator simultaneously. When applying the antenna of the present invention as a reader antenna for RFID, it is possible to design the antenna by an optimization technique using, for example, Pareto genetic algorithm. Specific examples of use of this Pareto genetic algorithm are as follows.

The sample antennas are estimated for performance by the EM simulation tool and then evaluated for conformance by the cost evaluation function. After evaluating the antennas, the optimized laws are applied to the optimized antennas. The cost evaluation function for the reader antenna is composed of equations (2) to (5).

(2)

(2)

(3)

(3)

(4)

(4)

(5)

(5)

In equations (2) and (3), Eff _Reader is the antenna efficiency at the operating frequency. BW _RFID represents a frequency bandwidth for _{RFID and} is set to 100 MHz in the present invention based on the UHF band 860 ~ 960 MHz used worldwide. The BW _Reader and CPBW _Reader represent the return loss bandwidth (S11 <-10 dB) and circular polarization bandwidth (axial ratio <3 dB) of the designed antenna, respectively. In cost estimation using Equations (1) and (2), Return loss Quality ( RQ ) and Axial ratio Quality ( AQ ) were added for qualitative evaluation of return loss and circular polarization axial ratio within operating bandwidth. . RQ and AQ allow the antenna to have a low return loss and a good circular polarization ratio in the 860-960 MHz band.

Equation (4) was set to the antenna size to the product of the wave number (wave number) k (2π / λ) to the smallest sphere radius r kr comprising an antenna Standardization (Size _Norm) to limit the size of the reader antenna.

Equation (5) is a cost evaluation function for optimizing the recognition region of the reader antenna. This equation calculates the maximum recognition distance from the reader antenna to the reader antenna's recognition zone ( RR _Reader ) and quantifies it by comparing it with the ideal ideal recognition zone RR _RFID . In the present invention, the ideal recognition area RR _RFID is set to a 3m × 3m rectangular area having a width of 9m ² on the assumption of a logistics ticket gate environment. According to the standard of commercial RFID reader, input power P _T was set to 1W and minimum detectable power P _{R, min} (minimum detectable power) was set to -50 dBmW. Tag Antenna Radiation Gain G _Tag is the gain of polarization on the E-plane when the dipole antenna emits. G _Reader represents the radiation gain of the reader antenna.

Next, the characteristics of the antennas according to the embodiment of the present invention will be described. FIG. 10 is a graph showing gain characteristics of the size of each of the antenna 10 having a single layer structure according to the first embodiment and the antenna structure 50 having a double layer structure according to the second embodiment. This graph shows the performance difference between these two antennas (10) and (50) .Gain log (dB) data according to the antenna size (kr) shown in the graph shows that the antenna of the two-ply structure It can be seen that better than single-layer structure in. In general, two or more multi-layer antennas show better gain characteristics than single-layer antennas. The dotted line in FIG. 10 means the maximum theoretical radiation gain that can be obtained at a given size of the limited antenna.

11 shows the return loss bandwidth of the multi-ply structured sample antenna 50 according to the second embodiment. The actual measurement results are roughly similar to the simulation results. As a result of the optimization of the genetic algorithm, the optimized antennas all operated with very low return loss and good circular polarization characteristics at 860MHz to 960MHz, the UHF band RFID frequency. In particular, the UHF band RFID shows low return loss and good circular polarization even at the operating frequency of 912 MHz.

Also, according to the actual measurement, the optimization antennas of the multi-layer structure showed superior characteristics in the forward gain than the optimization antennas of the single-layer structure. That is, the multi-layered optimized antenna showed a gain characteristic close to the theoretical maximum radiated gain value at the same antenna size ( kr ). FIG. 12 shows the circular polarization axial ratio in the omni-directional direction (θ = 0 °) of the sample antenna of FIG. 5, and it is possible to verify the characteristics of the high quality circular polarization at an operating frequency of 912MHz. FIG. 13 shows an omnidirectional (θ = 0 °) single polarization gain obtained by rotating a linear antenna at 912 MHz of a two-ply structured antenna. Considering the difference between the maximum gain and the minimum gain, the sample antenna emits a good circular polarization. FIG. 14 is a graph showing antenna radiation gain of 912 MHz at Φ = 0 ° of a double-ply antenna; FIG. FIG. 15 is a graph of antenna radiation gain of 912 MHz at Φ = 90 ° of a two-ply structure antenna.

The antenna 50 proposed in the second embodiment of the present invention is a two-ply optimized antenna, having an antenna size ( kr ) of about 3.2, a return loss bandwidth of 15.8% (904 MHz to 1038 MHz), and a circular polarization bandwidth of 31.9. % (780 MHz to 1071 MHz), radiation gain of about 6 dBi, and 91% radiation efficiency. The optimized multi-layered antennas show performance differences according to the limited number of changes in pitch angle, and the increase in the number of changes in pitch angle increases the return loss bandwidth and the circular polarization bandwidth. 16A to 16D are planar printing structure development views of the antenna lines when the number of changes of the pitch angle 91 is 1, 2, 3, and 4, respectively. FIG. 17 is a graph showing return loss of a multi-ply antenna having 14, 16, and 19 pitch angles 91. This graph shows that the return loss bandwidth of the antenna increases as the number of pitch angle changes increases. FIG. 18 is a graph showing the omnidirectional (θ = 0 °) circular polarization axis ratio of a multi-layered antenna having a pitch angle 91 of 14, 16, and 19 values. This graph shows that the circularly polarized bandwidth of the antenna increases as the number of pitch angle changes increases. Table 1 below shows the relationship between the pitch angle change frequency and the antenna performance.

 TABLE 1

Number of pitch angle changes Return Loss Bandwidth Circular polarization bandwidth 14 6.9% 14.18% 16 15.35% 15.1% 19 21.38% 33.2%

According to the invention, the phase of the current induced in the line is controlled by various pitch angles 91 to radiate high quality circular polarization in a wide band. The number and structure of internal antennas affects the radiation gain when the antenna is operating and is a design variable for increasing the radiation gain in all directions (θ = 0 °). When viewed from the antenna radiation plane parallel to the ground plane, the number of screw turns, the shape and electrical length of the entire line affects the radiation pattern and the return loss bandwidth, especially when the quarter-wave matcher around the feed By having a broadband return loss bandwidth, the system has a stable recognition area with low power loss in a wide band.

Antenna according to the above two embodiments is an antenna applicable to the UHF band (860 MHz ~ 960 MHz) RFID reader (reader), is designed to radiate high-gain circular polarization suitable for transmission and reception. While the conventional helix antenna has a constant pitch angle, the antenna of the present invention has a structure in which the pitch angle is freely increased and decreased, which is advantageous for radiating circular polarization in a wide band. This free pitch angle is advantageous in that the antenna of the present invention has a low operating frequency and can operate in a wide band because the electrical length can be increased in a limited size. In addition, the antenna of the present invention has an excellent structure in terms of radiation gain by having a multi-layered antenna structure inside to favor the remote recognition. Furthermore, the antenna body is constructed of microstrip structures on inexpensive dielectric substrates to meet practical purposes.

As mentioned above, although preferred embodiments of the present invention have been described in detail, those of ordinary skill in the art to which the present invention pertains should realize the present invention without departing from the spirit and scope of the present invention as defined in the appended claims. It will be appreciated that various modifications or changes can be made. For example, although an antenna having a two-ply structure has been described as an example of a multi-ply structure, even if a polygonal antenna line is overlapped with three or more plies, those skilled in the art will be able to change the embodiment relatively easily from the above description. Therefore, changes in the future embodiments of the present invention will not depart from the technology of the present invention.

As described above, the antenna according to the present invention is a helix antenna having a completely new structure, that is, a multi-layered polygonal helix antenna, and has the following advantages or effects.

The antenna of the present invention has a current phase characteristic advantageous to circular polarization characteristics by various pitch angles of the line, and can control the electrical length according to the frequency in a limited antenna size more flexibly than the general helix antenna, so that the excellent return loss characteristics of the broadband and It is easy to adjust the operating frequency.

In addition, since the antenna of the present invention folds the dielectric substrate to form various polygonal structures, it is easy to adjust the angular velocity and the radiation pattern of the circular polarization, and has a high gain radiation characteristic by the antenna of the inner stage to secure the recognition region at a long distance. have.

Furthermore, the antenna of the present invention is characterized by low return loss in broadband, high quality circular polarization radiation, adaptability of recognition region, etc., and is easy to manufacture at low cost.

Claims (9)

The antenna line includes a line section having a polygonal shape when viewed from a radiation plane parallel to the ground plane, the antenna line being matched with a feed line, the antenna line being at least perpendicular to the ground plane. An antenna having a polygonal helix structure, characterized in that it has a shape bent at one point. The antenna of claim 1, wherein the antenna line comprises only one layer of polygonal antenna lines when viewed from the radiation plane. The antenna of claim 1, wherein the antenna lines have multiple polygonal antenna lines of different sizes when viewed from the radiation plane. 4. The antenna line of claim 3, wherein the antenna line comprises an outer polygonal antenna line having an arbitrary polygon shape, at least one or more inner layer antenna lines arranged inside the outer antenna line to form a multi-layer structure, and antenna layers of each layer. Antenna of a polygonal helix structure, characterized in that it comprises a connecting line for connecting to each other. The antenna of claim 1, wherein the antenna line is a microstrip line that is printed and supported on a surface of a dielectric substrate bent in a polygonal shape and forms a polygon when viewed from the radiation plane. The polygonal helix structure antenna according to claim 1, wherein the dielectric substrate is made of a paper sheet capable of being folded to maintain a polygonal tubular shape. The antenna of claim 1, wherein the antenna line has a structure having negative and positive pitch angles by bending at multiple points in a direction perpendicular to the ground plane. 8. The polygonal helix structure of claim 7, wherein the pitch angle is set to a value such that a current wave induced in a line is constantly reduced to form a traveling wave in the line. The polygonal helix antenna of claim 1, wherein the feed line has an impedance of 50 Ω and an operating frequency of the antenna is in a frequency band of 860 MHz to 960 MHz.

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