KR20020069397A - Multiple bands type antenna Antenna and method for produeing the same - Google Patents

Abstract

PURPOSE: A multi-band type antenna and a method for fabricating the same are provided to enhance efficiency of an antenna by improving unbalance condition in the antenna. CONSTITUTION: A connector(10) includes a screw formed at the outer circumference of the cylindrical metal bar which is a cylindrical shape and has a predetermined length and a predetermined diameter. A connection part(14) is formed between a processing object(12) and the connector(10). The connection part(14) has a space(13). The first helical antenna part(15) is fabricated by forming a spiral shape on the connection part(14). The connection part(14) is covered by the dielectric body(20). A coating material(30) is molded on the first helical antenna(15).

Description

Multiple bands type antenna Antenna and method for produeing the same}

The present invention relates to a multi-band antenna and a method for manufacturing the same. More specifically, the dielectric wraps the outside of the lower portion of the connection terminal having a space between the helical antenna and the connector formed integrally to form an impedance transformer. The present invention relates to a multiband antenna formed by installing a separate helical antenna and a whip antenna at the center of a dielectric placed inside, and a method of manufacturing the same.

The general feeding structure of the small antenna used in the conventional wireless communication is a form of feeding the coaxial line directly. In the case of the monopole, the + part is fed to the coaxial line, and in the case of the dipole, the +, The part is fed to the antenna.

This method causes an unbalance between the feed lines of the antennas, which makes it difficult to actually match the impedances of the antennas. In addition, since the contact point between the antenna and the feed line is changed from time to time, the characteristics of the manufactured antenna are not constant and the efficiency of the antenna is considerably reduced.

As shown in FIG. 1, U.S. Patent No. 4,772,895 has been proposed, which relates to an antenna 500 for widening the frequency response, the structure having a feed port 550 including a signal feed part and a ground part and facing A helical first helical antenna 520 having both ends and having a first pitch and a first electrical length, wherein one end of the first helical antenna is coupled to a signal feed part of the feed port 550 and is opposed to And a second helical antenna 540 having both ends and representing a second pitch and a second electrical length.

The second helical antenna 540 is wound coaxially around a portion of the first helical antenna 520, and one end of the second helical antenna 540 is coupled to the ground of the feed port 550. Two pitches are approximately one half of the first pitch and the second electrical length is approximately one third of the first electrical length.

A cylindrical spacer means 530 disposed coaxially between the first helical antenna and the second helical antenna to electrically insulate the first helical antenna 520 and the second helical antenna 540 and the spacer means Reference numeral 530 is an antenna that is thin enough to be firmly coupled to the first helical antenna and the second helical antenna, thereby increasing the frequency response represented by the first helical antenna.

In the conventional antenna structure, a structure used between the first helical antenna installed inside the spacer means and the second helical antenna installed outside the ground means is used as a connecting means for grounding both of them. As a result, there is a problem in that the efficiency of the antenna is reduced and miniaturized.

In general, the unbalanced condition is divided into two types, axial antenna and normal mode. However, the case in which the helical antenna's outer edge is much smaller than the wavelength corresponding to the frequency used is called the normal mode. In general, the helical used in the wireless communication device generally corresponds to the normal mode.

The characteristic of the normal mode helical antenna is that the characteristic impedance is very large and the radiation resistance value corresponding to the actual radiation power is small. Therefore, as the overall input impedance value is very large, the return loss value is large due to a considerable impedance difference from the output impedance of 50 Ω at the actual terminal of the wireless communication device. do.

As shown in FIG. 2, there is shown another antenna structure of U.S. Patent No. 5,661,495, the structure of which transmits a radio signal as well as a feed point providing electrical coupling of the antenna device to the chassis 250 and the communication equipment. And / or an antenna device 200 having a circuit 230 for receiving, wherein the antenna device 200 is a helical antenna fixed to a cylindrical fixed terminal 260 to be fixed to the outside of the chassis 250. 210 and an antenna rod 220 that can slide through the helical antenna 210, the helical antenna 210 is a structure that is always coupled to the circuit 230 through the feed point.

On the other hand, increasing the bandwidth of the helical antenna 210 and the ground plane is tuned adjacent to the feed point and does not make a direct galvanic (direct current) electrical contact, the ground plane is coupled to the protective earth of the communication equipment and mirror current The structure is designed to hold.

In the conventional antenna structure as described above, when the antenna rod is extended (drawn) from the housing, the antenna rod and the helical antenna are connected in parallel to the circuit 230, and the antenna rod 220 is contracted into the chassis 250. If you put it), only the helical antenna is connected to the circuit 230.

On the other hand, the equivalent circuit at the time of installing the helical antenna in the general cylindrical structure is an equalization of the parallel resonant of the feeder and L and C as shown in Figure 3, the conventional spiral antenna is the length of the conventional monopole antenna Although the frequency is reduced, the resonance frequency is made the same, but the frequency becomes narrower due to the increase of the Q value due to L and C parallel resonance.

Therefore, the graph showing the electrical characteristics of a typical spiral antenna measured by VSWR and the Smith chart for showing the impedance measurement data. As shown in FIG. 4, the larger the VSWR value, the more the Smith chart has the impedance value farther from the center. The higher the antenna return loss, the narrower the bandwidth.

The bandwidth of the conventional antenna of the structure shown in FIGS. 1 to 2 is positioned in a frequency range having a VSWR value of 2 or less. Therefore, the conventional antenna has a VSWR value between 5-18 and the Smith chart has a narrow frequency because the impedance value of the Smith chart is far from the 50 kHz value at the center of the Smith chart. Able to know.

In addition, in the conventional antenna structure, there is a problem that the efficiency of the antenna is lowered because the unbalance condition that is a problem in the antenna is not improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its object is to improve the efficiency of the antenna by improving the unbalanced condition that is a problem in the antenna in the conventional antenna structure, and to satisfy various frequencies. It is an object of the present invention to provide an antenna and a manufacturing method for forming a multi-band capable of coping with a shift in frequency immediately.

1 to 2 are cross-sectional views showing the structure of a typical antenna.

3 is an equivalent circuit when installing a helical antenna in a general cylindrical structure

Figure 4a is a graph showing the VSWR measurement of the electrical characteristics after installing the helical antenna in the conventional cylindrical fixture, Figure 4b is a smith chart for showing the impedance measurement data after installing the helical antenna in the conventional cylindrical fixture.

Figure 5a is a flow chart showing a manufacturing process of the multi-band antenna to which the technique of the present invention is applied, Figure 5b is a flow chart showing another manufacturing process of the multi-band antenna of the present invention.

Figure 6 is a perspective view showing the structure of the present inventors antenna.

Figure 7 is a cross-sectional view showing a coupling structure of the fixing portion and the dielectric which is the main part of the present invention.

FIG. 8 is an equivalent circuit of a structure in which the fixing part and the first helical antenna are integrally formed in FIG.

FIG. 9A is a graph illustrating VSWR measurement of electrical characteristics of a structure in which a fixed part and a first helical antenna are integrally formed in FIG. 7, and FIG. 9B is impedance measurement data of a structure in which a fixed part and a first helical antenna are integrally formed. Smith chart to show.

10A to 10D are cross-sectional views showing an antenna structure of another embodiment of the present invention.

11A is a graph showing VSWR measurement of electrical characteristics after installing a second helical terminal on a structure in which a fixed part and a first helical antenna are integrally formed. FIG. 11B is a structure in which a fixed part and a first helical antenna are integrally formed. Smith chart for showing impedance measurement data after installing second helical terminal.

12A is a graph showing VSWR measurement of electrical characteristics after installing a third helical terminal on a structure in which a second helical antenna is installed, and FIG. 12B is an impedance measurement data after installing a third helical terminal on a structure in which a second helical antenna is installed. Smith chart to show.

※ Explanation of symbols about main part of drawing ※

10: connector 12: workpiece

13 space 14 connection

15: helical antenna 17: the original

20: dielectric 30: coating body

40: second helical antenna 50: whip antenna

60: third helical antenna S1: first processing process

S2: Second Processing Process S3: Third Processing Process

S4: Fourth Processing S5: Fifth Processing

An object of the present invention is to form a circular plate integrally with the connector formed with a screw on the outer circumferential surface and to form a fixing portion having a space on its upper surface and the connecting member formed integrally with the first helical antenna at the end of the fixing portion, It is achieved by a multi-band antenna characterized in that the inner portion of the first helical antenna constituting the connecting member and the center portion penetrated, and insert molding the coating material on the outside of the first helical antenna,

The antenna may be implemented by forming a connector having a screw formed on an outer circumferential surface of a cylindrical metal rod having a predetermined length and diameter, and processing the first machining to have a workpiece having a central portion penetrated therethrough. And a second processing step of forming a fixing part having a space in a portion where the workpiece and the connector formed by passing through the central portion are adjacent to each other, and having a spiral shape from a portion spaced a predetermined distance from the space of the fixing part. And a third processing step of forming a first helical antenna part, a first part of the first helical antenna formed by the third processing step, a central part penetrating therethrough, and a fixing part having a space and a first helical antenna being started. A fourth processing step of installing a dielectric to flow out of the part to surround the fixing part, and to the outside of the first helical antenna Is achieved by the fifth method of producing the multiple band-type antenna, it characterized in that is formed by a processing step to re-insert molding.

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

Figure 5a is a flow chart showing the manufacturing process of the multi-band antenna to which the technique of the present invention is applied, according to the present invention forms a connector 10 is formed on the outer peripheral surface of the cylindrical metal rod having a predetermined length and diameter And a workpiece formed by the first machining step S1 for processing the connector 10 to have the workpiece 12 penetrated therein, that is, the workpiece 12 formed through the central portion thereof. The connector 14 having the space 13 is formed in the portion adjacent to the connector 10 by the second machining step S2.

On the other hand, the third processing step (S3) and the third processing step of forming a first helical antenna portion 15 to have a spiral form from a portion spaced a predetermined distance from the space 13 of the connecting portion 14 It enters inside of the first helical antenna 15 formed by S3 and penetrates the center portion, and flows out of the portion where the connecting portion 14 and the first helical antenna 15 having the space 13 start. The dielectric 20 is installed by the fourth processing step S4 to surround the connecting portion 14.

After the dielectric 20 is installed, an antenna is manufactured by a fifth processing step S5 of insert molding the coating material 30 on the outside of the first helical antenna 15. Otherwise

As shown in FIG. 5B.

The present invention is to form a connector 10 is formed on the outer peripheral surface of the cylindrical metal rod having a predetermined length and diameter and to be processed to have a workpiece 12 through which the center portion is penetrated upwards of the connector 10. In the workpiece formed by the first processing step (S1), after performing the third processing step (S3) to form the first helical antenna (15) by forming the workpiece 12 to have a spiral shape, the original plate (17) The connecting portion 14 having the space 13 is formed in the portion adjacent to the start of the first helical antenna 15 formed integrally with the second through the second processing step (S2).

The connecting part 14 and the first helical antenna 15 having a space 13 are started in the inner part of the first helical antenna 15 formed by the third processing process S3 and penetrate the central part. The dielectric 20 is installed by a fourth processing step S4 that flows out of the portion to surround the connection portion 14.

After the dielectric 20 is installed, an antenna is manufactured by a fifth processing step S5 of insert molding the coating material 30 on the outside of the first helical antenna 15.

On the other hand, according to the antenna manufacturing method of another embodiment of the present invention, as shown in Figure 10a attached to the coating material 30 in the inside of the dielectric 20 formed by the third processing step (S3) before insert molding 2. A manufacturing method including a step of installing the helical antenna 40 and a plurality of steps including a step of installing the whip antenna 50 in the assembly after insert molding, as shown in FIG. 10B. It is possible to use a method of manufacturing an antenna forming a band.

Another manufacturing method of the present invention includes a method of coating a dielectric on an outer surface of a second helical antenna 40 installed inside the first helical antenna 15 and the second drawing as shown in FIG. 10C. After installing the helical antenna 20 and insert molding the covering material 30, a whip antenna 50 penetrating the center portion is installed or a third helical is provided at one end of the whip antenna 50 as shown in FIG. 10D. An antenna manufacturing method for laying the antenna 60 may be used.

In addition, by changing the structure of the covering material 30 by the insert molding to the cap may be to obtain the assembly time and the convenience of work.

The antenna manufactured by the above method improves the efficiency of the antenna by improving the unbalanced condition which is a problem in the antenna in the conventional antenna structure, and can satisfy various frequencies, so that the antenna is immediately moved in frequency due to various environments of the antenna. There is a coping effect.

On the other hand, according to another method of the present invention may change the process order to perform the third processing step after the second processing step (S2) to perform the second processing step (S2) after the third processing step (S3) and The reason for this depends on the order of processing depending on the convenience of processing.

Referring to the structure of the multi-band antenna manufactured by the manufacturing method of the present invention as described above are as follows.

6 is a perspective view showing the structure of an antenna to which the technique of the present invention is applied, whereby the multi-band antenna 1 to which the technique of the present invention is applied is integrally formed with a connector 10 having a screw 10 formed on an outer circumferential surface thereof. ) And a connecting portion 14 having a space 13 is formed on the upper surface thereof, and the first helical antenna 15 is integrally formed at the end of the connecting portion 14, but inside the first helical antenna 15. While being buried as a dielectric 20 penetrated through the center is installed.

The installation structure of the dielectric is installed inside the first helical antenna (15) formed by the third processing step (S3) of the antenna manufacturing method as shown in the accompanying drawings, Figures 5 to 7, the central portion penetrates, It is a structure installed so as to surround the connecting portion 14 is leaked to the outside of the beginning portion of the connecting portion 14 and the first helical antenna 15 having a space 13, the outside of the first helical antenna 15 It is a structure formed by insert molding the coating | covering material 20.

On the other hand, the reason why the dielectric 20 is formed to surround the connecting portion 14 by flowing out to the starting portion of the connecting portion 14 and the first helical antenna 15 is because the covering material 30 is space 13 during insert molding. This is to prevent the space 13 drawn in to form the impedance transformer.

As illustrated in FIG. 5, the working effect of the antenna of the present invention having a single band as shown in FIG. 5 is that the connector 10 having a screw formed on the outer circumferential surface is fixed to the housing and the disc 17 sags. Will be prevented.

On the other hand, when a part of the cylindrical metal rod is cut off, the space 13 formed between the first helical antenna 15 and the disc 17 integrally formed at the end of the connecting portion 14 becomes an impedance transformer.

More specifically, FIG. 9A is a graph showing VSWR measurement of electrical characteristics of a structure in which the first helical antenna 15 is integrally formed at the connecting portion 14 in FIG. 7, and FIG. As a Smith chart for showing impedance measurement data of a structure in which a first helical antenna 15 is integrally formed, the antenna of the present invention has a prominent series inductance effect where a space 13 is formed, and this is an impedance transformer. Becomes

Although there is an impedance change according to the length of the first helical antenna 15, but the bandwidth is generally determined by the structure, the soluble content (capacitance component) of the helical is wideband in the initial impedance matching step by deformation of the feed portion. Have characteristics.

Indeed, the increase in series inductance effect is synonymous with the decrease in the series capacitance effect between the impedance transformer and helical antenna, which is generally seen in helical antennas.

Therefore, it can be seen that resonance occurs in space, and the results of the above structure are described as follows.

When the resonant circuit of the antenna generally causes parallel resonance, the Q value (goodness of the lossy reactance element or the resonant circuit) becomes considerably large, resulting in a considerably smaller bandwidth.

However, in the present invention, it can be seen that the desired bandwidth can be obtained in a wide frequency band if the structure of the structure is converted into a distributed constant circuit and the input impedance viewed from the feed point causes series resonance.

On the other hand, the modulation of the parallel resonance, which is a general characteristic by the impedance transformer, into the series resonance is because the inherent capacitance value of the helical antenna is canceled by the series inductance using the structure to induce the antenna having only the pure resistance value.

At this time, the parallel resonance and the series resonance of the C and the spiral element L in the transformer are inserted by inserting a transformer that can be equalized in a parallel structure of R and C between the feeding part and the parallel resonance as shown in FIG. 8. As a characteristic, the adjacent frequency of the center frequency due to double resonance becomes the series resonance frequency.

Therefore, both frequency and gain are improved due to resonance of adjacent frequencies. This means that the bandwidth is widened by compensating the increase of the Q value due to L and C parallel resonance due to the series resonance.

On the other hand, since the value of C in the transformer is controlled in the equivalent circuit according to the size of the space 13, it is possible to flexibly adjust the series resonance frequency adjacent to the center frequency, which is in the transformer regardless of the matching circuit according to the required bandwidth. According to the C value, the usable bandwidth range can be controlled, and the width of the first helical antenna can be made wide to adjust the bandwidth.

Meanwhile, in the antenna having the structure of FIG. 5, the whip antenna 50 is inserted into the inside of the first helical antenna 13 as shown in FIG. 10B of the first helical antenna 15. When installed to penetrate through the center, the contact is formed at the bottom of the structure to change the resonance characteristics to obtain the desired frequency and gain.

This is because only the first helical antenna 15 is inserted to change the resonance characteristics by inserting the whip antenna 50 into a fixed structure that forms a space, which is the point of the whip antenna 50 and at the same time the helical antenna at the same time. Because of the coupling effect, the coupling effect between the whip antenna 50 and the helical antenna affects both the series resonance characteristic due to the impedance transformer and the parallel resonance characteristic due to the spiral element, resulting in a small decrease in the Q value.

If you look at the gain comparison according to the position of the whip antenna connected to the helical antenna,

1. Gain comparison according to frequency when whip antenna is pulled from helical antenna

Frequency [MHZ] Conventional antenna [dBm] The present invention [dBm] Gain comparison [dB] 822 -20.64 -19.86 +0.78 851 -21.17 -21.15 +0.02 867 -20.53 -20.37 +0.16 898 -20.87 -20.70 +0.17

2. Comparison of gain with frequency when whip antenna is inserted into helical antenna

Frequency [MHZ] Conventional antenna [dBm] The present invention [dBm] Gain comparison [dB] 822 -19.31 -19.22 +0.09 851 -20.53 -20.25 +0.28 867 -19.56 -19.32 +0.24 898 -19.93 -19.93 +0.00

Accordingly, the present invention can extend the frequency by compensating parallel resonance, which is a general characteristic of a monopole antenna and a dipole antenna, by serial resonance by modifying only a fixed structure without modifying an existing antenna.

Indeed, the increase in series inductance effect is generally equivalent to the reduction in series capacitance effect between the fixed structure and the spiral antenna.

In the conventional antenna structure, the gain decreases when the frequency range is wider and the gain increases when the frequency range is reduced, whereas the gain increases when the frequency range is wider, and the gain increases when the frequency bandwidth decreases. Going down is a big difference between the conventional antenna and the present invention.

On the other hand, Figure 10a is a cross-sectional view showing another structure of the antenna forming a multi-band according to the present invention, one end is grounded to the disc 17 and the other end is formed inside the dielectric 20 while forming a free end The second helical antenna 30 has a structure formed by installing the second helical antenna 30, and in order to prevent the coating material from entering the space and forming the space during insert molding, the reason why the lower dielectric is drawn out is formed outside the first helical antenna 15. This is to allow the second helical antenna 30 to be placed inside, without making the contact point.

Meanwhile, a coating layer made of a dielectric may be further formed on an outer surface of the second helical antenna 30 installed inside the first helical antenna 15, wherein the coating layer is formed of the first helical antenna 15 and the second helical antenna. This is because the contact point of the antenna 30 can be more reliably prevented.

As shown in FIG. 10B, the effect of the antenna, which is an embodiment of the present invention, in which the second helical antenna 30 is installed inside the first helical antenna 15 to form a dual band, is described. As shown in Figs. 11A and 11B, the band has a bandwidth of 230 MHz in the band where the VSWR is 2 or less at the frequencies 800 MHz to 900 MHz, and a 250 MHz bandwidth at the frequencies 1800 MHz to 1900 MHz.

Meanwhile, as shown in FIG. 10C, in the structure in which the second helical antenna 30 is installed inside the first helical antenna 15 and the whip antenna 50 penetrates the center thereof, the helical antenna is installed in the helical antenna. Looking at the gain comparison according to the position of the electrically connected whip antenna,

1. Gain comparison according to frequency when whip antenna is pulled from helical antenna

Frequency [MHZ] Conventional antenna [dBm] The present invention [dBm] Gain comparison [dB] 890 -47.72 -46.58 +1.14 960 -47.69 -46.72 +0.97 1710 -52.37 -51.89 +0.48 -1880 -53.17 -51.85 +1.32

2. Comparison of gain with frequency when whip antenna is inserted into helical antenna

Frequency [MHZ] Conventional antenna [dBm] The present invention [dBm] Gain comparison [dB] 880 -49.69 -49.15 +0.54 960 -50.52 -49.80 +0.72 1710 -54.69 -54.34 +0.35 1880 -56.72 -55.22 +1.5

Therefore, it can be seen that the antenna having the structure of one embodiment of the present invention has an improved bandwidth than when only the first helical antenna is installed, and this also deforms only the fixed structure without modifying the existing antenna, and actually a monopole antenna. In addition, the frequency can be extended by compensating the parallel resonance, which is a general characteristic of the DIPOLE antenna, with serial resonance.

As illustrated in FIG. 10D, the cover 30 is installed with a whip antenna 50 penetrating through the center after insert molding, and a third helical antenna 60 is installed on the top of the whip antenna to tripple band. As shown in FIGS. 12A and 12B, the effect of the antenna, which is another embodiment of the present invention forming a (Triplel-Band), has a bandwidth of 140 MHz between 800 MHz and 900 MHz in a VSWR value of 2 or less and 1800. It has a bandwidth of 700MHz at MHz-1900MHz and 1885MHz-2200MHz.

On the other hand, if you look at the gain comparison according to the position of the whip antenna connected to the helical antenna,

1. Gain comparison according to frequency when whip antenna is pulled from helical antenna

Frequency [MHZ] Conventional antenna [dBm] The present invention [dBm] Gain comparison [dB] 824 -48.19 -47.47 +0.72 894 -47.98 -47.47 +0.51 1750 -53.21 -53.08 +0.13 1870 -53.22 -51.75 +1.47 1750 -59.69 -58.75 +1.25 1870 -59.42 -58.35 +1.07

2. Comparison of gain with frequency when whip antenna is inserted into helical antenna

Frequency [MHZ] Conventional antenna [dBm] The present invention [dBm] Gain comparison [dB] 824 -50.65 -50.22 +0.43 894 -51.05 -50.39 +0.66 1750 -55.46 -55.04 +0.42 1870 -54.92 -53.62 +1.3 1885 -60.18 -59.01 +1.17 2200 -60.07 59.09 0.98

Accordingly, it can be seen that the antenna having the structure of another embodiment of the present invention also has an improved bandwidth than the antenna forming the general triple band, such as the antenna forming the single band and the dual band described above. ) It is possible to extend the frequency by compensating parallel resonance which is a general characteristic of antenna and DIPOLE antenna with serial resonance.

On the other hand, the antenna having the structure of forming the triple band may be formed to control the size and shape of the space to form a single band and dual band, the present invention according to the deformation of the structure space of the antenna resonant circuit in parallel resonance By converting to serial resonance, any antenna that generally generates parallel resonance at the center frequency can obtain a frequency range of 2-3 times more than the conventional one, and the gain is also improved.

Such a multi-band antenna and a manufacturing method of the present invention has a space between the helical antenna and the connector integrally formed in the dielectric to surround the outside of the lower portion of the connection terminal forming the impedance transformer, the upper portion is placed inside the dielectric By installing separate helical antennas and whip antennas in the center of the antenna structure to improve the efficiency of the antenna by improving the unbalanced condition which is a problem in the antenna in the conventional antenna structure, and to satisfy the various frequencies, the center frequency due to various environments of the antenna It is effective to deal with the movement immediately.

Claims (16)

A first processing step of forming a connector having a screw formed on an outer circumferential surface of a cylindrical metal rod having a predetermined length and diameter, and machining the connector to have a workpiece having a central portion penetrated therethrough; A second processing step of forming a fixing part having a space at a portion where the central portion penetrates the connector and the connector are adjacent; A third processing step of forming a first helical antenna part by forming a spiral shape from a part spaced a predetermined distance from the space of the fixing part; The dielectric is installed inside the first helical antenna portion formed by the third processing process and penetrates the center portion and flows out to the outside of the fixing portion having the space and the portion where the first helical antenna starts and surrounds the fixing portion. A fourth processing step of installing; And a fifth processing step of insert molding a coating material on the outside of the first helical antenna. The method of manufacturing a multiband antenna according to claim 1, wherein the processing step of performing the third processing step after the second processing step is performed to perform the second processing step after the third processing step. The method of manufacturing a multiband antenna according to claim 1, further comprising the step of installing a second helical antenna inside the dielectric formed by the fourth machining step before insert molding the coating material. The method of manufacturing a multiband antenna according to claim 3, comprising the step of installing a second helical antenna and installing a whip antenna penetrating the center portion after insert molding the covering material. The method of claim 3, wherein a dielectric is coated on an outer surface of the second helical antenna installed inside the first helical antenna. The method of manufacturing a multiband antenna according to claim 1, further comprising the step of installing a whip antenna on the assembly after insert molding. The method of claim 6, further comprising a helical antenna disposed at one end of the whip antenna. The method of manufacturing a multiband antenna according to claim 1, wherein the coating material by insert molding is formed as a cap. The method of claim 1, wherein the size of the space is adjusted to adjust a usable frequency range. A connecting member having a circular plate integrally formed with a connector formed with a screw on an outer circumferential surface thereof, and having a fixing portion having a space on an upper surface thereof, and having a first helical antenna integrally formed at the end of the fixing portion; A dielectric embedded in the first helical antenna constituting the connecting member and having a central portion penetrated therethrough; Multi-band antenna, characterized in that the insert molding the coating material on the outside of the first helical antenna. The multiband antenna of claim 10, wherein one end of the circular plate is grounded and the other end of the circular plate forms a free end, and a second helical antenna is provided inside the dielectric. 12. The multiband antenna according to claim 11, wherein the second helical antenna is installed and the whip antenna penetrates the center portion after insert molding the covering material. The antenna of claim 10, wherein a whip antenna penetrates the center after the insert molding to cover the covering material. 13. The multiband antenna of claim 12, further comprising a third helical antenna attached to one end of the whip antenna. The multiband antenna according to claim 10, wherein a coating layer made of a dielectric is formed on an outer surface of the second helical antenna installed inside the first helical antenna. 11. The multiband antenna of claim 10, wherein the cross-sectional shape of the first helical antenna has a plate shape.