GB2436168A

GB2436168A - Liquid coupled antenna using a plurality of different polar liquids

Info

Publication number: GB2436168A
Application number: GB0625705A
Authority: GB
Inventors: Samsung Electro-Mechanics Ltd; Hyun Hak Kim; Jae Chan Lee; Jong Lae Kim; Seok Min Woo; Yong Bum Lee
Original assignee: Samsung Electro Mechanics Co Ltd
Current assignee: Samsung Electro Mechanics Co Ltd
Priority date: 2006-03-16
Filing date: 2006-12-22
Publication date: 2007-09-19
Anticipated expiration: 2026-12-22
Also published as: KR100703220B1; DE102006060566A1; ITMO20060425A1; GB0625705D0; FI20065843L; FI20065843A0; GB2436168B

Abstract

A liquid coupled antenna 50 comprises a sealed container 51 with an inner space divided into a plurality of sections 51a-c by at least one partition wall P1, P2. Polar liquids 52a-c are housed in respective sections 51a-c of the container inner space and differ in at least one of electrical conductivity, dielectric constant and permeability. A conductive material radiator 55 is disposed in the inner space of the sealed container 51 and a feed is arranged to extend through the container 51 to connect with the said radiator. The radiator 55 may be electrically insulated from the polar liquids by a layer of insulating material. The feed may be a radio frequency cable 53 with an inner feed line 53a insulated from an outer ground part 53c by a sheath of insulating material 53b. The inner feed line 53a connects to the radiator 55 whilst the ground part 53c may be connected to at least one of the polar liquids. The polar liquids 52a-c may be at least one selected from the group consisting of water, alcohol, acetonitrile, acetone, a SAR solution and an electrolyte. The polar liquids 52a-c may also contain a conductive powder, an ethylene glycol-based anti-freeze liquid and/or a corrosion inhibitor such as nitrite, triethanolarnine or mixtures thereof. The radiator 55 may be a monopole, dipole, helical or printed conductive-pattern structure. The liquid-coupled antenna is intended to provide high gain, broadband and/or improved low frequency performance for compact antenna structure which may be readily used in mobile hand-held devices.

Description

LIQUID COUPLED ANTENNA

CLAIM OF PRIORITY

[0001] This application claims the benefit of Korean Patent Application No. 2006-24475 filed on March 16, 2006 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND PART OF TE INVENTION

Field of the Invention

[0002] The present invention relates to a liquid coupled antenna, more particularly, in which a resonance frequency is easily determined, a frequency bandwidth is more effectively enhanced and various antenna properties can be improved through two types of liquids.

Description of the Related Art

[0003] Antennas are essential for wireless and broadcasting communication in a mobile communication terminal and can be varied in their structure and material in accordance with a frequency bandwidth and usage thereof. In general, the antennas for use in the mobile communication terminal tend to be miniaturized due to the demand for smaller size and lighter weight of the terminal.

(0004] However, the more compact antennas experience a

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degradation in their properties. Chiefly, the smaller-sized antennas are narrowed in their bandwidth. Thus, antennas such as DVB-H, DVB-T and DVB-UMTB for use in a VHF/UHF bandwidth, are degraded in transmission/reception efficiency due to narrower bandwidth. Moreover, the antennas of smaller size are lowered in radiation gain since the antenna has gain proportional to volume thereof.

StTh*ARY OF THE INVENTION [0005] The present invention has been made to solve the foregoing problems of the prior art and therefore an aspect of the present invention is to provide a novel liquid coupled antenna which utilizes two liquids to satisfy more various antenna properties.

[0006] According to an aspect of the invention, the invention provides a liquid coupled antenna. The liquid coupled antenna includes a sealed container having an inner space divided into a plurality of sections by at least one partition wall; a plurality of polar liquids housed in the respective sections and differing in at least one of electrical conductivity, dielectric constant and permeability; a radiator disposed in the inner space of the sealed container, and made of a conductive material; and a feed part extending from an exterior of the sealed container into an interior of the sealed container to connect to the radiator.

[0007] Preferably, the radiator has a surface applied with an insulating material so as not to contact the polar liquids directly. The polar liquids may expand a frequency bandwidth but a desired resonance frequency bandwidth can be maintained by a pre-designed radiator structure.

[0008] The partition wall may be varied in the number, structure and size thereof. Also, the radiator comprises a conductivepatternformedonorinsjdethepartjtionwall Here, the radiator is formed inside the insulating partition wall so as not to contact the polar liquids directly.

[0009] Preferably, the liquid coupled antenna further includes a ground part extending from the exterior of the sealed container into the interior of the sealed container to contact the polar liquids. The ground part contacts the polar liquids to further enhance bandwidth properties.

[0010] Here, the ground part and feed parts comprise an RE' cable structure including a feed line and a ground part line that are electrically insulated from each other by an insulator.

Preferably, the RF cable is of a coaxial cable structure. That is, the feed line is connected to the radiator, the insulator comprises an insulating sheath for surrounding the feed line, and the ground part line is formed on the insulating sheath to be in contact with at least one of the polar liquids.

[0011] Each of the polar liquids comprises one selected from a group consisting of water, methanol, ethanol, butanol, acetonitrile, acetone and SAR solution.

[0012] The polar liquids with different characteristics may be prepared by adding an electrolyte or a conductive powder into a same kind of polar liquid. That is, at least one of the polar liquids comprises an electrolytic solution with at least one typeof electrolyte solvedtherein. On the otherhand, at least one of the polar liquids comprises a conductive powder that is attractable by magnetic force.

[0013] Preferably, the polar liquids further include an ethylene glycol solution. Moreover, the polar liquids further include a corrosion inhibitor. The corrosion inhibitor comprises one selected from a group consisting of nitride, triethanolamine and mixtures thereof.

[0014] The invention can be configured in combination with various radiator structures. The radiator comprises a structure selected from a group consisting of monopol, dipole and helical structures. Alternatively, the radiator comprises a conductive pattern formed on a solid dielectric body.

BRIEF DESCRIPTION OF TBE DRAWINGS

[0015] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: [0016] FIGs. la and lb are perspective views illustrating p conventional liquid coupled antennas; [0017] FIG. 2 is a perspective view illustrating a liquid coupled antenna according an embodiment of the invention; and [0018] FIGs.3a to 3c are perspective views illustrating liquid coupled antennas each employing a different radiator structure according to a preferred embodiment of the invention.

DETAILED DESCRIPTION OF TRE PREFERRED EMBODIMENT

[0019] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0020] Vigorous studies have been underway to miniaturize antennas while achieving wide band performance and boosting gain thereof. Meanwhile, the inventor judged that the conventional solid antenna would not be able to overcome narrower band and lower radiation gain resulting from more compact size. Thus, the inventor proposed in Korean Patent Application No. 2005-0070730 (entitled "Broadband Antenna Using Liquid Medium," published on August 2, 2005) an antenna structure (hereinafter "liquid-coupled antenna") in which a conventional conductive radiator is coupled with a new radiation medium of a polar liquid having very low conductivity and a certain dielectric constant. Such a liquid coupled antenna achieves wide band and low band performance easily. The liquid coupled antennas 10 and 10' as described in the aforesaid document are depicted in FIGs. la and lb. [0021) 1s shown in FIG. la, the liquid coupled antenna 10 includes a radiator 5 and a sealed container 1. The radiator is connected to a feed part 3 and configured as a wire or monopol structure. The sealed container 1 has a polar liquid 2 housed therein. The radiator 6 is combined with the polar liquid 2 having new radiation medium properties to adjust a radiation frequency without lengthening or geometrically modifying a conductor pattern.

[0022] This liquid coupled antenna may be configured in combination with various conventional antenna structures such as a chip antenna. For example, the liquid coupled antenna 10' shown in lb has a radiator 15 configured as a helical structure and connected to a feed part 13. Similarly to FIG. la, the radiator 15 is disposed in the sealed container 11 to contact the polar liquid 12.

[0023] The liquid coupled antennas shown in FIGs. la and ib, have the radiator disposed inside the sealed container to be in direct contact with the polar liquid. In this structure, the conventional radiator is combined with the polar liquid to adjust a resonance frequency, notably, in a wide band. In the liquid coupled antenna, an adjustable width of the resonance frequency depends on a single liquid, thereby hardly changing antenna properties variously.

[0024) In addition, typically, the antennas for the mobile communication terminal need to be designed not to deteriorate antenna properties in various environments where the terminal is employed. So do the liquid coupled antennas.

[0025] FIG. 2 is a perspective view illustrating a liquid coupled antenna according to an embodiment of the invention.

(0026] Referring to FIG. 2, the liquid coupled antenna 20 of the invention includes a sealed container 21 filled with a polar liquid 22 and a radiator 25 disposed in the sealed container 21.

(0027] The sealed container 21 according to this embodiment has first and second inner spaces 21a and 21b divided by a partition wall. The first and second inner spaces 21a and 21b are filled with first and second polar liquids 22a and 22b of different types, respectively.

[0028] The first and second polar liquids 22a and 22b of this embodiment have very low but certain conductivity and dielectric constant. The polar liquids 22a and 22b include but not limited to at least one selected from a group consisting of water, methanol, ethanol, butanol, acetonitrile, acetone and SAR solution. However, the polar liquids should be preferably low in electrical conductivity to improve radiation gain. The polar liquids have an electrical conductivity of preferably 10 S/rn or less, and more preferably 8 S/rn or less. The polar liquids may be represented by water.

[0029] "The polar liquids of different types" of this specification refer to polar liquids differing in at least one of electrical conductivity, dielectric constant and permeability which govern radiation properties. For example, the first and second polar liquids 22a and 22b are polar liquids of different types or polar liquids of different compositions which each are selected from a group consisting of water, methanol, ethanol, butanol, acetonitrile, acetone and SAR solution. Alternatively, the first and second polar liquids 22a and 22b can be of the same type, differing only in the mixing method (kind and/or addition amount) of electrolytes or a conductive powder. Here, electrolytes are a factor for electrical conductivity, while the conductive powder is a factor for magnetic properties.

[0030] The first and second polar liquids 22a and 22b are selected to differ in at least one of electrical conductivity, dielectric constant and permeability and are adequately positioned in a respective desired area depending on the partition wall P designed. The two polar liquids and arrangement thereof as described above can contribute to antenna designs with various properties.

[0031] In this embodiment, the radiator disposed inside the sealed container 21 is connected to the feed part extending outside. The radiator 25 is wire-structured, and extends through the partition wall P inside the sealed container 21 to be in contact with the two liquids 22a and 22b. Here, the radiator may demonstrate different characteristics depending on the type of the polar liquids. Also, two characteristics of the polar liquids 22a and 22b can be suitably combined to improve a desired frequency bandwidth more precisely.

[0032] However, according to the invention, the radiator is not necessarily in contact with both of the polar liquids. For example, optionally, the radiator may contact only one of the polar liquids (see FIG. 3a) and the radiator itself may be applied with an insulating material not to contact the polar liquids directly (see FIGs. 3a to 3c) [0033] Furthermore, unlike a conventional solid conductor, the first and second polar liquids 22a and 22b are easily affected by environments where the antennas are used, thereby undermining reliability thereof.

[0034] To relieve the problem, the polar liquids 22a and 22b may further include an ethylene glycol solution, which is a non-freezing solution. The polar liquids 22a and 22b in combination of the ethylene glycol solution may be beneficially applied when the polar liquids 22a and 22b are water. The polar liquids 22a and 22b may further include a corrosion inhibitor with or without the ethylene glycol solution to prevent undesired corrosion in a metal medium such as the radiator 25 or feed part 23 which may be in direct contact with the polar liquids 22a and 22b. The corrosion inhibitor is selected from a group consisting of nitride, triethanolamine and mixtures thereof, although not limited thereto.

[0035] The invention can be variously embodied according to divisional configuration of the inner space by the partition wall or modification in the antenna structure.

(0036] Especially, the polar liquids, when in contact with the radiator, may lead to too great change in a resonance frequency determined by the radiator, thereby hardly improving a bandwidth as desired.

[0037] To overcome this problem, as shown in FIGs. 3a to 3c, according to the invention, preferably, an insulating material is applied on the radiator designed to suit a specific resonance frequency bandwidth. Here, the polar liquids, even if not in direct contact with the radiator by the insulating material, are electromagnetically coupled with each other to thereby engage in radiation.

(0038] Moreover, as shown in FIGs. 3a to 3c, the antenna structure (i.e., radiator structure) of the invention can be variously embodied by modifying the partition wall.

(0039] The liquid coupled antenna 30 of FIG. 3a includes a cylindrical sealed container 31, a radiator 35 disposed in the container 31 and applied with the insulating material 37, and an RF cable 33 having a feed line 33a and a ground part 33c formed therein.

(0040] The sealed container 31 is divided into first and second sections 31a and 31b by the substantially cylindrical partition

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wall P. The first and second sections 31a and 31b are filled with first and second polar liquids 32a and 32b, respectively.

The radiator 35 of a helical structure of the invention is disposed only in the first section 3la. Here, the second polar liquid 3lbrnay influence antenna properties along with the first polar liquid 31a, even if with a relatively moderate degree due to its distance from the radiator 35.

[0041] Moreover, the helical radiator 35 has pitch angle and spacing designed so as to attain a desired resonance frequency bandwidth. The helical radiator 35, as described above, is applied with the insulating material 37. Thus the helical radiator 35 is electromagnetically coupled with the first polar liquid 32a without direct contact therewith to perform radiation.

f0042] In this embodiment, the feed part and the ground part are simply configured as a single cable structure. But the RE' cable 33 employed in this embodiment includes a feed line 33a directly connected to the radiator 35, an insulating sheath 33b for surrounding the feed line 33a, and a ground part 33c formed on the insulating sheath 33b. Here, the insulating sheath 33b electrically insulates the feed line 33a from the ground part 330.

(0043] As in this embodiment, the ground part 33c may feature a coaxial cable structure for surrounding the insulating sheath 33b. An additional insulating sheath (not illustrated) may be disposed around the ground part 33c. The RE' cable 33 is at least partially inserted into the first section 31a through an end face of the container 31 in such a fashion that the feeding line 33a exposed at one end of the RE' cable 33 is connected to one end of the radiator 35 and the ground part 33c exposed at the one end of the RE' cable 33 contacts the polar liquids 32. By virtue of this structure, the polar liquids 32a and 32b and the radiator can function as an antenna. In this embodiment, the RE' cable 33 is of a coaxial cable structure but may have various known configurations in which, for example, the feed line is insulated from the feed line by an insulator.

[0044] As described above, the ground part 33c of the RF cable 33 may contact the first polar liquid 32a to realize desired antenna properties. This structure allows the liquid coupled antenna 30 to significantly boost properties of a resonance frequency bandwidth of the radiator 35 itself.

[0045] FIG. 3billustratesaliquid coupled antenna 40 in which a radiator 45 is formed in a partition wall P according to another embodiment of the invention.

[0046] The liquid coupled antenna 40 includes a cylindrical container 41 having a partition wall P formed along a longitudinal cross-section and an RF cable 43 having a feed line 43a and a ground part 43c formed therein. The radiator 45 applied to this embodiment is formed on or inside the partition wall P. (0047] Typically, the partition wall P is made of an insulating material in a like manner to the container 41. In a case where the radiator 45 is disposed inside the partition wall P, the partition wall P serves as an insulating material to prevent the radiator 45 from making direct contact with the first and second polar liquids 42a and 42b.

[0048] In this embodiment, similarly to FIG. 3a, the feed part and the ground part may be configured as a single cable structure to assure a simple RE' coaxial cable structure. That is, the RE' cable 43 includes a feed line 43a directly connected to the radiator 45, an insulating sheath 43b for surrounding the feed line 43a, and a ground part 43c formed on the insulating sheath 43b. More specifically, the feed line 43a exposed at one end of the RE' cable 43 is connected to the radiator 45. The RE' cable 43 can be fixed integrally to the sealed container 41 and the radiator 45. However, optionally, the RE' cable 43 may be detachably configured with respect to the sealed container 41.

[0049] Furthermore, the RF cable 43 can be at least partially inserted through an end face of the container 41 so that the ground part line 43c contacts the first or second polar liquid 42a or 42b directly. This structure allows the liquid coupled antenna 40 to significantly boost properties of a resonance frequency bandwidth of the radiator 45 itself.

[0050] According to the embodiments, the sealed container has an inner space divided into two sections by a partition wall but alternatively, as shown in FIG. 3c, at least two partition walls may be adopted to divide the inner space into at least three sections. Here, at least three polar liquids may be used to improve various antenna properties.

[0051] Referring to FIG. 3c, the liquid coupled antenna 50 of this embodiment includes a cylindrical sealed container 51, a radiator 55 disposed inside the container 51 and applied with an insulating material, and an RF cable 53 having a feed line 53a and a ground part line 53c formed therein.

[0052] The sealed container 51 has an inner space divided into three sections 51a, Sib and 51c by two partition walls P1 and P2 which are installed along a latitudinal cross-section thereof. The first section 51a is filled with the first polar liquid 52a, the second section 51b is filled with the second polar liquid 52b and the third section 51c is filled with the third polar liquid 52c.

[0053] A radiator 55 of a monopol structure of this embodiment extends through the first and second partition walls P1 and P2 to contact the first to third polar liquids 52a, 52b, and 52c.

Here, unlike FIG. 3a, the first to third polar liquids 52a,52b and 52c exert similar effects over radiation properties of the antenna.

[0054] Similarly to the aforesaid embodiment, the RF cable includes a feed line 53a directly connected to the radiator 55, an insulating sheath 53b for surrounding the feed line 53a and a ground part line 53c formed on the insulating sheath 53b.

[0055] As described above, the liquid coupled antenna of the invention can utilize at least two polar liquids with different properties to be housed in a container having various configurations of a partition wall. Also, according to the invention, the radiator is configured to be applicable to various conventional antenna structures. The radiator features e.g., monopol, helical and wire configurations. But the invention may directly employ a chip antenna structure having a conductor patterned as a radiator on a dielectric block.

[0056] As set forth above, according to exemplary embodiments of the invention, a liquid coupled antenna adopts at least two polar liquids to exhibit different radiation properties by means of a partition wall. Here, the polar liquid types and divided area geometries by the partition wall can be modified to achieve various antenna properties. Moreover, the radiator is applied with an insulating material not to make direct contact with the polar liquids. Additionally, a ground part is formed in direct contact with the polar liquids to further improve a bandwidth.

[0057] While the present invention has been shown and described in connection with the preferred embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

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That Is Claimed Is: 1. A liquid coupled antenna comprising: a sealed container having an inner space divided into a plurality of sections by at least one partition wall; a plurality of polar liquids housed in the respective sections and differing in at least one of electrical conductivity, dielectric constant and permeability; a radiator disposed in the inner space of the sealed container, and made of a conductive material; and a feed part extending from an exterior of the sealed container into an interior of the sealed container to connect to the radiator.

2. The liquid coupled antenna according to claim 1, wherein the radiator has a surface applied with an insulating material so as not to contact the polar liquids directly.

3. The liquid coupled antenna according to claim 1, wherein the radiator comprises a conductive pattern formed on or inside the partition wall.

4. The liquid coupled antenna according to claim 3, wherein the partition wall comprises an insulating material, and the radiator comprises an insulating material formed inside the partition wall so as not to contact the polar liquids *1 directly.

5. The liquid coupled antenna according to claim 1, further comprising a ground part extending from the exterior of the sealed container into the interior of the sealed container to contact the polar liquids.

6. The liquid coupled antenna according to claim 5, wherein the ground part and feed parts comprise an RF cable structure including a feed line and a ground part line that are electrically insulated from each other by an insulator.

7. The liquid coupled antenna according to claim 6, wherein the feed line is connected to the radiator, the insulator comprises an insulating sheath for surrounding the feed line, and the ground part line is formed on the insulating sheath to be in contact with at least one of the polar liquids.

8. The liquid coupled antenna according to claim 1, wherein each of the polar liquids comprises one selected from a group consisting of water, methanol, ethanol, butanol, acetonitrile, acetone and SAR solution.

9. The liquid coupled antenna according to claim 1, wherein at least one of the polar liquids comprises an electrolytic solution with at least one type of electrolyte solved therein.

10. The liquid coupled antenna according to claim 1, where at least one of the polar liquids comprises a conductive powder that is attractable by magnetic force.

11. The liquid coupled antenna according to claim 1, wherein the polar liquids further comprise an ethylene glycol solution.

12. The liquid coupled antenna according to one of claims 1 to 11, wherein the polar liquids further comprise a corrosion inhibitor.

13. The liquid coupled antenna according to claim 12, wherein the corrosion inhibitor comprises one selected from a group consisting of nitride, triethanolamine and mixtures thereof.

14. The liquid coupled antenna according to claim 1, wherein the radiator comprises a structure selected from a group consisting of monopol, dipole and helical structures.

15. The liquid coupled antenna according to claim 1, wherein the radiator comprises a conductive pattern formed on a solid dielectric body.