KR20070081295A - Telescopic antenna - Google Patents

Abstract

A multiple stage retractable antenna is provided to enlarge an operation bandwidth of the antenna by using an impedance converter which is formed on a helical antenna portion. A multiple stage retractable antenna has two operation states, such as a long mode and a short mode. The antenna includes a conductive load antenna(200), an upper helical antenna(100), a conductive fixing member, and a lower helical antenna(300). The upper helical antenna is installed on the load antenna. At the long mode, the upper helical antenna is electrically coupled with an upper end of the load antenna. The conductive fixing member has a hollow structure for enclosing the load antenna, so that the load antenna is moved therein. The fixing member is fixed on a terminal and electrically coupled with a lower end of the load antenna at the long mode. The lower helical antenna is electrically coupled with a lower portion of the fixing member.

Description

Multistage Retractable Antenna {TELESCOPIC ANTENNA}

1 is a drawing showing a drawing state of a multi-stage retractable antenna according to an embodiment of the present invention.

2 is a view illustrating an insertion state of a multistage retractable antenna according to an embodiment of the present invention.

3 is a diagram illustrating an upper helical antenna portion of a multi-stage retractable antenna according to another embodiment of the present invention.

4 is a diagram illustrating an upper helical antenna unit of a multi-stage retractable antenna according to another embodiment of the present invention.

5 is a view showing a lower helical antenna portion of a multi-stage retractable antenna according to another embodiment of the present invention.

6 is a view showing a lower helical antenna unit of a multi-stage retractable antenna according to another embodiment of the present invention.

7 is a view showing a drawing state of a conventional retractable antenna;

8 is a view showing an insertion state of a conventional retractable antenna;

Explanation of symbols on the main parts of the drawings

100: upper helical antenna unit 110: upper helix

120: upper helix cover 130: upper trans-metal

200: rod antenna portion 210: first rod

220: second load 230: third load

240: fourth rod 250: fifth rod

300: lower helical antenna portion 310: lower helix

320: lower transmetal

The present invention relates to a multi-stage retractable antenna, and more particularly, to a multi-stage retractable antenna having an electrical length including a helical antenna on the top and bottom thereof.

A wireless communication terminal such as a mobile phone is essentially provided with an antenna for transmitting and receiving wireless signals. As the antenna, an external antenna such as a helical antenna, a rod antenna, a retractable antenna combining a helical antenna and a rod antenna, and an internal antenna such as an inverted L-type antenna and a Planar Inverted F Antenna (PIFA) are widely used.

7 and 8 show a conventional retractable antenna. The conventional retractable antenna is largely comprised of the rod antenna part 10 and the helical antenna part 20 with reference to FIG. The rod antenna portion 10 includes a rod 12 made of a conductive material and a rod antenna cover 18 covering the rod 12. A conductive stopper 14 is coupled to the lower portion of the rod antenna unit 10 so that the rod antenna unit 10 is fixed so as not to be drawn out by a predetermined height, and the transmetal 24 and the rod 12 are electrically connected when the rod antenna unit 10 is pulled out. Be sure to In addition, a knob 16 is formed on an upper portion of the rod antenna portion 10 to limit the insertion depth of the rod antenna portion 10 and to provide a user with convenience of operation. The helical antenna unit 20 includes a conductive transmetal 24 electrically connected to an internal circuit of the terminal and a helix 22 coupled to the upper portion of the transmetal 24. In addition, the helix 22 is protected by the helix cover 26. An upper portion 28 of the helix cover 26 has an opening larger than the outer diameter of the rod antenna cover 18 but smaller than the outer diameter of the knob 16 to allow movement of the rod antenna portion 10 in a limited range. . On the other hand, the helical antenna unit 20 is fixedly coupled to the terminal 30 by a screw formed in the transmetal 24.

Referring to FIG. 7, the conventional retractable antenna operates as a main radiator because the rod 12 is fed through the transmetal 24 and the stopper 14 when the rod antenna unit 10 is pulled out. The helix 22 fed by 24 also acts as a radiator. On the other hand, when the rod antenna portion 10 is inserted, referring to FIG. 8, since the rod 12 is electrically separated from the transmetal 24, the rod 12 does not operate as a radiator, and the helix connected to the transmetal 24 is formed. 22) Only the radiator acts. On the other hand, by adjusting the length of the rod antenna portion 10, it is possible to adjust the overlap length of the helix 22 and the rod 12 in the inserted state, thereby adjusting the influence by the electromagnetic coupling of the two conductors.

In general, the antenna should be manufactured to have a predetermined electrical length (1/4 of the wavelength in the case of a monopole antenna) determined by the wavelength to be transmitted and received. Therefore, the length of the antenna must be extended for use in long-wavelength services, for example, Terrestrial Digital Multimedia Broadcasting (T-DMB) services using low frequency bands below 300 MHz. However, according to the prior art, the electrical length of the antenna is determined by the length of each of the helix 22 and the rod 12, and it is impossible to extend the electrical length of the antenna by insertion and withdrawal. Therefore, in order to extend the electrical length of the antenna, it is necessary to extend the rod 12 or the helix 22. In this case, the overall size of the antenna increases, so it is difficult to apply. In particular, when the T-DMB function is combined with a mobile phone using a high frequency band of 900 MHz or higher, the antenna's electrical length is short when the antenna is inserted, so it is impossible to service the T-DMB. In order to receive, the length of the rod 12 becomes too long to be practical.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object thereof is to provide a retractable antenna that enables electrical transmission and reception of a low frequency signal to be greatly extended when the antenna is drawn out.

In addition, an object of the present invention is to provide a retractable antenna that can be kept small at the time of insertion, even if the electrical length is greatly extended during extraction.

According to an aspect of the present invention for achieving the above object, in a retractable antenna for a wireless terminal having two operating states of the pulled out state and the inserted state, a conductive rod antenna, provided on the rod antenna, An upper helical antenna unit electrically coupled to an upper end of the rod antenna in a pulled out state, and has a hollow structure for capturing the rod antenna to enable movement of the rod antenna and is fixed to the terminal. There is provided a retractable antenna including a conductive fixing member electrically coupled to a lower end, and a lower helical antenna unit electrically coupled to a lower portion of the fixing member.

Preferably, the rod antenna is not connected to the fixing member in the inserted state, and the upper helical antenna portion is electrically coupled to the fixing member in the inserted state.

Preferably, the rod antenna includes a protrusion connected to an upper portion of the fixing member in an inserted state, and the upper helical antenna portion is electrically coupled to the protrusion in the inserted state.

More preferably, the upper helical antenna portion and / or the lower helical antenna portion helix to operate as a radiator; And a support part supporting the helix and electrically coupled to the helix, wherein the support part has an outer diameter smaller than an inner diameter of the helix and includes an impedance transformer projecting inwardly of the helix.

The fixing member may be electrically coupled with an internal circuit of the terminal.

Alternatively, a lower end of the lower helical antenna unit may be electrically coupled with an internal circuit of the terminal.

In addition, the rod antenna preferably has a foldable multi-stage structure.

More preferably, the rod antenna comprises two or more rods, the lower rod having a larger inner diameter than the upper rod.

The rod antenna includes three or more rods, and an intermediate rod may preferably have a larger inner diameter than rods above and below it.

Further, preferably, the upper helical antenna portion and / or the lower helical antenna portion is a helix that operates as a radiator, a support portion electrically coupled to the rod antenna in a drawing state, and electrically connects the helix and the support portion to the It includes an impedance transformer of the open form on one side, forming a space between the helix and the support.

The fixing member may be electrically coupled with an internal circuit of the terminal.

Alternatively, a lower end of the lower helical antenna unit may be electrically coupled with an internal circuit of the terminal.

In addition, the rod antenna preferably has a foldable multi-stage structure.

More preferably, the rod antenna comprises two or more rods, the lower rod having a larger inner diameter than the upper rod.

The rod antenna includes three or more rods, and an intermediate rod may preferably have a larger inner diameter than rods above and below it.

In this specification, the term "electromagnetic coupling" means that two elements are arranged with or without a dielectric so that a current path is not formed between the two elements and is electrically isolated but mutual current is induced by electromagnetic waves. As used herein, the term "electrical coupling" is used to mean that two elements are electromagnetically coupled, or two elements are combined such that a current path is formed between the two elements so that charge can move with each other.

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

1 and 2 are diagrams illustrating a multi-stage retractable antenna according to an embodiment of the present invention. 1 and 2, the multi-stage retractable antenna of the present invention may include an upper helical antenna unit 100, a rod antenna unit 200, and a lower helical antenna unit 300.

The upper helical antenna unit 100 may be wound around the hollow upper transmetal 130 and the upper transmetal 130, and may include a conductive upper helix 110 that operates as a radiator. The transmetal 130 and the helix 110 may be protected by being covered with the upper helix cover 120 made of an insulator material. In the opening formed at the center of the upper transmetal 130, the first rod 210 may be inserted as described below to allow electrical connection between the upper helical antenna unit 100 and the rod antenna unit 200.

The upper helical antenna unit 100 may have an outer diameter that is substantially the same as the upper outer diameter of the lower transmetal 320 to be described later, so that the outer diameter may coincide when the upper helical antenna unit 100 is inserted. The upper helix 110 has an outer diameter that can be inserted into the upper helix cover 120, and when the upper helical antenna unit 100 is inserted, an electrical that can operate as an antenna along with the lower helix 310 as described below. It may be formed to have a length.

The rod antenna unit 200 may have a foldable multistage structure and may include first to fifth rods 210, 220, 230, 240, and 250 of a cylindrical conductive material. The first rod 210 is inserted into the central opening of the upper transmetal 130, and the first rod upper stopper 212 may be formed at an upper portion thereof. The second rod 220 may be inserted below the first rod 210. A lower end of the first rod 210 is bent to reduce an inner diameter, and a second rod upper stopper 222 is formed at an upper end of the second rod 220 to limit the length of the second rod 220. . In addition, a lower portion of the second rod 220 is inserted into the third rod 230, and withdrawal may be restricted by the second rod lower stopper 224 at the upper portion 232 of the bent third rod.

The third rod 230 is connected to the upper and lower parts by the connector 234 at the center, the connector 234 may protrude out of the rod 230. The fourth rod 242 may be inserted into the lower portion of the third rod 230. Again, the lower portion 236 of the third rod may be bent and the stopper 242 may be formed on the upper portion of the fourth rod 240 to limit the movement of the rod. In addition, the fourth rod 240 and the fifth rod 250 may be coupled in the same manner. As such, the multi-stage structure is formed such that the inner diameter of the intermediate third rod 230 is the largest, so that the upper and lower rods 220, 240, 250 can be inserted into the third rod 230, thereby As a result, the length of the extraction can be greatly extended while minimizing the internal diameter at the time of insertion. Alternatively, the multi-stage structure may be formed such that the inner diameter of the fifth rod 250 is the largest, so that the rods 210, 220, 230, and 240 are all inserted into the fifth rod. However, in order to minimize the overall diameter, it is advantageous to configure the inner diameter of the third rod 230 to be the largest.

Meanwhile, a lower stopper 254 is formed at a lower portion of the fifth rod 250, and may be electrically coupled to the leaf spring 322 inside the lower transmetal 320 when being pulled out, as described below. The length of each of the rods 210, 220, 230, 240, 250 can be determined to be an electrical length that is connected to the upper helix 110 and the lower helix 310 to be operated as an antenna upon withdrawal, as described below. have.

The lower helical antenna unit 300 has a screw formed and wound around the transmetal 320 coupled to the terminal 400 and the protrusion 324 below the transmetal, and the lower helix 310 electrically coupled to the transmetal 320. ) May be included. The trans metal 320 may be formed in a hollow shape to allow the rod antenna unit 200 to move. The leaf spring 322 is installed inside the transmetal 320 to achieve electrical coupling with the rod antenna unit 200. In addition to the leaf spring 322, it is also possible to make the electrical connection while fixing the rod antenna unit 200 to be movable using a long spring or the like. The internal circuit of the terminal 400 may be connected to the lower transmetal 320 or may be connected to the lower end of the lower helix 310. The lower helix 310 may have an appropriate electrical length to act as an antenna upon antenna withdrawal and insertion, as described below.

Referring to FIG. 2, when the antenna is inserted, the second rod 220 is inserted into the first rod 210 and the third rod 230, and the first rod 210 and the third rod 230 are inserted. An upper portion of the may be inserted into the upper helix 110. In addition, the fifth rod 250 is inserted into the fourth rod 240, the fourth rod 240 is inserted into the third rod 230, and the lower portion of the third rod 230 is formed of the transmetal 320. It can be inserted inward. The connector 234 is in contact with the upper portion of the lower transmetal 320, and the connector 234 may be connected to the upper transmetal 130 again. Accordingly, the lower helix 310 and the upper helix 110 may be electrically connected to each other through the transmetals 130 and 320. Alternatively, it is also possible for the upper helix 110 and the lower transmetal 320 to be directly connected without the connector 234. In this case, the rod antenna unit 200 is completely isolated from the inserted state, but may affect the radiation characteristics of the antenna by electromagnetic coupling with the helix 110 and 310. The electromagnetic coupling with the helix 110 or 310 may be adjusted by changing the multi-stage structure of the rod antenna unit 200 or by changing the length of each rod. In addition, the transmetals 130 and 320 may be electromagnetically coupled to each other to feed the helix 110.

When the internal circuit of the terminal is connected to the lower transmetal 320, the terminal operates as a parallel connected monopole antenna composed of the lower helix 310 and the upper helix 110, and the terminal inside the terminal at the lower end of the lower helix 310. When the circuit is connected, it may operate as a monopole antenna having an electrical length from the lower end of the lower helix 310 to the upper end of the upper helix 110. The antenna at such insertion can be designed to resonate with services that use relatively high frequencies (ie, short wavelengths). When using low frequency (that is, long wavelength), an antenna can be taken out and used as mentioned later.

Referring to Fig. 1, the operation of drawing out the antenna will be described. At the time of drawing, the load antennas 210, 220, 230, 240, 250 are drawn out to a position restricted by the stopper, and can be electrically connected to each other. In addition, since the first rod upper stopper 212 is connected to the upper transmetal 130, and the upper transmetal 130 is electrically connected to the upper helix 110, the rod antenna unit 200 and the helix 110 are provided. Can be electrically coupled. Meanwhile, the lower stopper 254 of the fifth rod 250 may be electrically coupled to the transmetal 320 while being fixed by the leaf spring 322. Accordingly, the lower helix 310 may be electrically coupled to the rod antenna unit 200 through the transmetal 320.

As such, the lower helix 310, the rods 210, 220, 230, 240, 250 and the upper helix 110 may be electrically connected in series. Therefore, when the internal circuit of the terminal is connected to the lower transmetal 320, the lower helix 310 and the parallel connection monopole antenna including the rods 210, 220, 230, 240 and 250 and the upper helix 110 may operate. Can be. In addition, when the internal circuit of the terminal is connected to the lower end of the lower helix 310 can operate as a monopole antenna consisting of the lower helix 310, the rods (210, 220, 230, 240, 250) and the upper helix (110). have.

According to the present embodiment, since the helix 110 and 310 are connected to both the upper end and the lower end of the antenna, the electrical length can be extended without greatly extending the substantial length of the antenna. In particular, since the lower helix 310 is installed in the internal space of the terminal occupied by the rod antenna, the influence of the size increase of the antenna is small. In addition, since the rod antenna unit 200 is formed in multiple stages, the antenna may be kept small when the antenna is inserted, and the electrical length may be further extended during extraction. In services using very long wavelength signals such as T-DMB, it is particularly useful to extend the electrical length significantly.

In another embodiment of the present invention, the upper helical antenna portion 100 may be replaced with the upper helical antenna portion 100a as shown in FIG. In FIG. 3, the same reference numerals are used for the same components as in the previous embodiment, and will not be described in detail. A conductive impedance transformer 132 protruding into the helix 110 may be formed in the trans metal 130 of the upper helical antenna unit 100a of the present embodiment. Impedance transformer 132 is formed to have an outer diameter smaller than the inner diameter of the helix 110, it may be formed in a semi-cylindrical shape so that the rod antenna portion can be inserted in the antenna insertion state. On the other hand, when the rod antenna portion is not inserted into the upper helical antenna portion 100a in the antenna insertion state, the impedance transformer 132 may be formed in a semi-cylindrical shape having no cavity inside.

Alternatively, the multi-stage retractable antenna of the present invention may use the lower helical antenna portion 300a as shown in FIG. 5 as the lower helical antenna portion. In Fig. 5, the same reference numerals are used for the same components as in the previous embodiment and will not be described in detail. The lower helical antenna unit 300a of the present embodiment may include an impedance transformer 326. The impedance transformer 326 is formed of a conductive material so as to protrude and extend inwardly of the helix 310, and may be formed in a semi-cylindrical shape so that the rod antenna part is inserted inward in the inserted state of the antenna. Alternatively, the impedance transformer 326 may be formed in a semi-cylindrical flat inside.

Such impedance transformers 132, 326 are disclosed in Applicant's US Patent No. 6,219,008, which is incorporated herein by reference. According to the present embodiments, the impedance transformers 132 and 326 can be included to induce series resonance to expand the bandwidth of the antenna, and the bandwidth of the impedance transformer 132 can be easily adjusted by adjusting the size.

In another embodiment, the upper helical antenna portion 100b as shown in FIG. 4 can be used. In Fig. 4, the same reference numerals are used for the same components as in the previous embodiment and will not be described in detail. The upper helical antenna unit 100b may include an impedance transformer 134 that electrically connects the helix 110 and the transmetal 130. The impedance transformer 134 may be formed by cutting a portion of a cylinder, and may be formed so that one side thereof is opened, and a space may be formed between the upper transmetal 130 and the helix 110 by the impedance transformer 134. .

Alternatively, the lower helical antenna portion 300b as shown in FIG. 6 may be used as the lower helical antenna portion. In Fig. 6, the same reference numerals are used for the same components as in the previous embodiment and will not be described in detail. The lower helical antenna portion 300b may include an impedance transformer 328 that interconnects the helix 310 and the transmetal 320 and forms a space therebetween.

These impedance transformers 134, 328 are described in detail in Applicants' Patents Nos. 374752 and 415385, which are incorporated herein by reference. According to this embodiment, it is possible to extend the bandwidth of the antenna by inducing series resonance by the impedance transformers 134 and 328.

Further, both the upper helical antenna portion and the lower helical antenna portion are connected to the upper helical antenna portions 100a and 100b shown in FIGS. 3 and 4 and the lower helical antenna portions 300a and 300b shown in FIGS. 5 and 6, respectively. It is also possible to replace. In this case, the bandwidth of the antenna can be further extended by an impedance transformer formed in the upper and lower helical antenna units.

While the present invention has been described above in connection with specific embodiments of the present invention, this is only an example and the present invention is not limited thereto. For example, the term trans-metal used in the above descriptions is not intended to limit the component to be made only of metal, and may be made of a plastic other Any material can be used. In addition, the rod antenna portion of the multi-stage structure may include more loads or less loads than the described configuration, or may use any known configuration. In addition, those skilled in the art will be able to make various changes and modifications based on the described embodiments, and it is obvious that such changes and modifications are also within the scope of the present invention.

According to the present invention, by installing the helix in the upper and lower parts of the load antenna, and by configuring the load antenna in multiple stages, while maintaining the size of the antenna at the time of insertion, while extending the electrical length of the antenna and using a low frequency band such as T-DMB Can support

In addition, according to the present invention, by adding an impedance transformer between the upper and lower helix and the transmetal, the bandwidth of the antenna can be expanded and the bandwidth can be easily adjusted.

Claims (15)

In the retractable antenna for a wireless terminal having two operating states of the drawing state and the insertion state, Conductive rod antennas; An upper helical antenna unit installed on an upper portion of the rod antenna and electrically coupled to an upper end of the rod antenna in a pulled out state; A conductive fixing member having a hollow structure for capturing the rod antenna to enable movement of the rod antenna and fixed to the terminal and electrically coupled to a lower end of the rod antenna in a pulled out state; And And a lower helical antenna unit electrically coupled to a lower portion of the fixing member. The method of claim 1, In the inserted state, the rod antenna is not connected to the fixing member, And the upper helical antenna portion is electrically coupled with the fixing member in the inserted state. The method of claim 1, The rod antenna includes a protrusion connected to an upper portion of the fixing member in an inserted state. And the upper helical antenna portion is electrically coupled with the protrusion in the inserted state. The method according to any one of claims 1 to 3, The upper helical antenna unit and / or the lower helical antenna unit Helix acting as a radiator; And A support for supporting the helix and electrically coupled with the helix, The support portion has a smaller outer diameter than the inner diameter of the helix and includes an impedance transformer protruding inward of the helix, retractable antenna. The method of claim 4, wherein And the fixing member is electrically coupled with an internal circuit of the terminal. The method of claim 4, wherein A lower end of the lower helical antenna unit is electrically coupled with an internal circuit of the terminal. The method of claim 4, wherein The rod antenna has a foldable multi-stage structure, retractable antenna. The method of claim 7, wherein The rod antenna includes two or more rods, A retractable antenna, wherein the lower rod has an inner diameter larger than that of the upper rod. The method of claim 7, wherein The rod antenna includes three or more rods, A retractable antenna, wherein the intermediate rod has a larger inner diameter than the rods above and below it. The method according to any one of claims 1 to 3, The upper helical antenna unit and / or the lower helical antenna unit Helix acting as a radiator; A support part electrically coupled to the rod antenna in a pulled out state; And And an impedance transformer having an open shape on one side, which electrically connects the helix and the support and forms a space between the helix and the support. The method of claim 10, And the fixing member is electrically coupled with an internal circuit of the terminal. The method of claim 10, A lower end of the lower helical antenna unit is electrically coupled with an internal circuit of the terminal. The method of claim 10, The rod antenna has a foldable multi-stage structure, retractable antenna. The method of claim 13, The rod antenna includes two or more rods, A retractable antenna, wherein the lower rod has an inner diameter larger than that of the upper rod. The method of claim 13, The rod antenna includes three or more rods, A retractable antenna, wherein the intermediate rod has a larger inner diameter than the rods above and below it.

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