Antenna, and manufacturing method therefor

[0002] The present invention relates to an antenna and a manufacturing method therefor. Particularly, the present invention relates to an antenna and a manufacturing method therefor, in which the sensitivity characteristic of the dual band antenna utilizing a plurality of frequency bands is improved, and at the same time, the antenna can be miniaturized.

[0003] The generally known CDMA mobile communication terminal having a plurality of frequency bands is capable of transmitting and receiving voices and motion pictures. The dual mode antenna which is used in such a CDMA terminal has to be capable receiving signals through a plurality of frequency bands.

[0004] In this dual band antenna, a contacting-separating type antenna and a vertical antenna are coupled together, or a linear monopole antenna and a vertical antenna are coupled together. Or primary and secondary antennas are coupled together in a serial or parallel form.

[0005] One of this conventional vertical dual band antennas is disclosed in Japanese Patent Application Laid-open No. Hei-10-322122.

[0006] This dual band antenna is constituted a shown in FIG. 1. That is, there is formed a primary coil 10 which has a certain length and pitches. Further, a secondary coil 30 which has a length and pitches larger that those of the primary coil 10 is vertically connected to the lower end of the primary coil 10, thereby forming a dual band antenna 40.

[0007] In this antenna 40, a frequency band is provided over the entire primary and secondary coils 10 and 30, while another frequency band is provided in the secondary coil 30 which has a length and pitches larger than those of the primary coil 10.

[0008] In this antenna 40, however, the primary coil 10 and the secondary coil 30 are connected in the vertical direction, and therefore, the overall length of the antenna is extended, with the result that the miniaturization of the mobile communication terminal becomes difficult.

[0009] Meanwhile, in an attempt to overcome the above described disadvantages, recently the antenna is installed within the terminal, and when the terminal is used, the antenna is drawn out. In this method, however, an antenna accommodating space has to be provided within the terminal, and therefore, the mobile communication terminal cannot be miniaturized.

[0010] The present invention is intended to overcome the above described disadvantages of the conventional techniques.

[0011] Therefore it is an object of the present invention to provide an antenna in which the dual band antenna capable of receiving signals through a plurality of frequency bands is improved in its sensitivity characteristic, and the antenna can be miniaturized.

[0012] It is another object of the present invention to provide a manufacturing method for an antenna, in which the desired dielectric constant can be obtained by arbitrarily selecting the dielectric material so as to minimize the designing limitation, and the conductive line of the antenna can be constituted in an accurate manner so as to minimize the generation of defects during the manufacture.

[0013] In achieving the above objects, the antenna according to the present invention includes: a spiral primary coil; and a spiral secondary coil connected to one end of the primary coil, disposed outside the primary coil, and having pitches larger than those of the primary coil, whereby a frequency band is provided over the entire primary and secondary coils, and another frequency band is provided in the secondary coil.

[0014] In another aspect of the present invention, the method for manufacturing an antenna according to the present invention includes the steps of: forming a first cylindrical body; forming a first securing spiral channel around the first cylindrical body starting from an end of the first body to a certain part of the first body and having a predetermined length and pitches; installing a primary coil through the first securing spiral channel; forming a second cylindrical body having an inside diameter same as or larger than an outside diameter of the cylindrical first body, so as to receive the first cylindrical body; forming a second securing spiral channel around the second cylindrical body starting from an end of the second cylindrical body to a certain part of the second cylindrical body and having a predetermined length and pitches; installing a secondary coil through the second securing spiral channel; and inserting the first cylindrical body into the second cylindrical body, and contacting a portion of the exposed secondary coil of the second cylindrical body to a portion of the exposed primary coil of the first cylindrical body.

[0015] In still another aspect of the present invention, the method for manufacturing an antenna according to the present invention includes the steps of: i) preparing inner and outer ceramic substrates; ii) forming a via hole in each of the inner and outer ceramic substrates, and filling a conductive paste in the via hole; iii) forming a primary coil pattern on a surface of the inner ceramic substrate by using an antenna pattern forming means; iv) forming a secondary coil pattern on a surface of each of the outer ceramic substrates by using an antenna pattern forming means; v) bonding the inner and outer substrates together with the inner substrate having the primary coil disposed between upper and lower sheets of the outer substrates having the secondary coils, so as to make the primary and secondary coils connected together in a spiral form through the via holes of the inner and outer substrates; and vi) cutting the substrates thus bonded together into individual antennas.

[0016] In still another aspect of the present invention, the method for manufacturing an antenna according to the present invention includes the steps of: i) preparing green sheets consisting of inner and outer ceramic substrates; ii) forming via holes in each of the inner and outer ceramic substrates of the green sheet, and spreading a conductive pattern in each of the via holes; iii) forming primary coil patterns on a surface of each of the inner ceramic substrates by using an antenna pattern forming means; iv) forming secondary coil patterns on a surface of each of the outer ceramic substrates by using an antenna pattern forming means; v) stacking the inner substrates with the primary coils formed thereon between upper and lower sheets of the outer substrates with the secondary coils formed thereon so as to make the via holes of the inner and outer substrates aligned; vi) cutting the stacked structure into individual antennas; and vii) baking the inner and outer substrates of the stacked structure with the primary and secondary coils formed thereon at a predetermined temperature so as to complete the antenna.

[0017] In still another aspect of the present invention, the method for manufacturing an antenna according to the present invention includes the steps of: i) preparing a plurality of flexible substrates; ii) forming a diagonal conductive pattern on a first flexible substrate of the plurality of the flexible substrates; iii) forming a plurality of inclined conductive patterns on a surface of a second flexible substrate of the plurality of the flexible substrates at predetermined gaps; iv) winding the first flexible substrate around a cylindrical support; and v) winding the second flexible substrate around the first flexible substrate.

[0018] The above object and other advantages of the present invention will become more apparent by describing in detail the preferred embodiment of the present invention with reference to the attached drawings, in which:

[0019] FIG. 1 illustrates the constitution and the installed state of the conventional dual band antenna;

[0020] FIG. 2 is a schematic view showing the constitution of the dual band antenna according to the present invention;

[0021] FIG. 3 is a sectional view showing the installed state of the dual band antenna according to the present invention;

[0022] FIGS. 4a, 4band 4cillustrate the manufacturing process for the dual band antenna according to the present invention;

[0023] FIG. 5 illustrates the installing procedure for the dual band antenna in a first embodiment of the present invention;

[0024] FIG. 6 schematically illustrates the manufacturing process for the dual band antenna in a second embodiment of the present invention;

[0025] FIG. 7 schematically illustrates the manufacturing process for the dual band antenna in a third embodiment of the present invention;

[0026] FIG. 8 schematically illustrates the manufacturing process for the dual band antenna in a fourth embodiment of the present invention; and

[0027] FIG. 9 is a graphical illustration showing the reception band and sensitivity characteristics of the dual band antenna according to the present invention.

[0028] The present invention will be described in detail referring to the attached drawings.

[0029] FIG. 2 is a schematic view showing the constitution of the dual band antenna according to the present invention. FIG. 3 is a sectional view showing the installed state of the dual band antenna according to the present invention.

[0030] The dual band antenna according to the present invention includes: a primary coil 100; and a secondary coil 200 surrounding the primary coil 100, thereby forming an antenna 300.

[0031] The primary coil 100 is formed in a spiral shape, and has a predetermined length and predetermined pitches, while the primary coil 100 has also a constant coiling diameter. The center line of the primary coil 100 is disposed substantially on a vertical line.

[0032] Meanwhile, as shown in FIG. 4a, the primary coil 100 is a spiral coil accommodated within a spiral securing channel 120 which has a predetermined length and predetermined pitches and which is coiled around a cylindrical first body 110. The cylindrical first body 110 is made of a resin, a ceramic or a magnetic material.

[0033] Under this condition, the primary coil 100 consists of a wire of a certain diameter which is made of Cu, Ag or a shape memory alloy. Or the primary coil 100 consists of a rolled band. Thus the primary coil 100 is secured into the spiral securing channel 120 of the first body 110, while the upper port ion of the primary coil 100 is made to project from a side of the first body 110.

[0034] The secondary coil 200 which is integrally connected to the primary coil 100 is connected to the upper portion of the primary coil 100. The secondary coil 200 has a spiral form, and has a length and pitches larger than those of the primary coil 100.

[0035] The secondary coil 200 is made of a material and a diameter same as those of the primary coil, or is made of a rolled band. The vertical axis of the secondary coil 200 lies on the same position as that of the primary coil.

[0036] Meanwhile, a second body 220 has a supporting hollow space 210 to accommodate the first body 110 around which the primary coil 100 is wound along the spiral securing channel 120. Another spiral securing channel 230 is formed around the second body 220, and the spiral securing channel 230 has a length and pitches same as those of the secondary coil 200, so that the secondary coil 200 can be inserted into the spiral securing channel 230.

[0037] As shown in FIG. 4b, the second body 220 around which the secondary coil 200 is wound has a dielectric constant and a permeability same as those of the first body 110, or different from those of the first body 110.

[0038] As shown in FIG. 4c, the primary coil 100 which is wound around the first body in the spiral form projects to the outside of the first body 110. The projected portion of the first coil 100 is electrically connected to the secondary coil 200 which is wound around the second body 220, with the result that a dual band antenna 300 is formed.

[0039] In the primary and secondary coils 100 and 200, the pitches and the angular direction can be adjusted, so that a single band antenna can be formed for receiving signals through a single frequency band.

[0040] Thus by the primary and secondary coils 100 and 200, an antenna of a single frequency band is formed. Further, the secondary coil 200 which is wound around the second body 220 in the spiral form makes it possible to form an antenna for receiving signals through another frequency band. Thus a dual band antenna 300 can be formed.

[0041] Then as shown in FIG. 5, the antenna 300 which includes the primary and secondary coils 100 and 200 is inserted into a cap housing 310 which is made of a resin.

[0042] Then a filling stuff consisting of an epoxy resin or a thermosetting resin is injected into the cap housing 310, so that the dual band antenna can be securely accommodated within the cap housing 310.

[0043] Under this condition, the antenna 300 does not require any particular securing means, but is firmly secured by filling the filling stuff 320 into the cap housing 310. Accordingly, the workability and the productivity are improved.

[0044] Alternatively, the dual band antenna 300 which includes the primary and secondary coils 100 and 200 can be formed by an insert injection molding by making a plastic composite material or a ceramic dielectric material surround the antenna 300. Here, the ceramic dielectric material has to have a dielectric constant of 2˜50.

[0045] As graphically illustrated in FIG. 9, the antenna 300 which includes the primary and secondary coils 100 and 200 shows an expanded frequency reflection band width and a decreased frequency reflection magnitude (dB). Thus the frequency receiving capability becomes superior.

[0046] FIG. 6 schematically illustrates the manufacturing process for the dual band antenna in a second embodiment of the present invention. In order to form two spiral coils having different pitches and diameters, a plurality of via holes 440 are formed at regular intervals on an inner substrate 410aand outer substrates 410b, thereby forming a ceramic substrate (or a tefrone or resin substrate may be used). On the ceramic substrate, there are formed conductive patterns by using a pattern forming means.

[0047] The conductive patterns are formed in the following manner. That is, a coating layer is formed upon the ceramic substrate by using Cu, Ni, Ag or Au and by applying a non-electrolytic coating. Then the coated layer is etched by the photo lithography, so that primary coating patterns 430acan be formed on the inner substrate 410a, and that secondary coil patterns 410bcan be formed on the outer substrates 410b.

[0048] Then the portion of the ceramic substrate where the coil patterns are not formed is cut off, and a cream solder is printed between the inner substrate 410aand the outer substrates 410bto carry out a soldering. Or the general adhesive and a glass frit is used to bond the inner and outer substrates 410aand 410btogether.

[0049] When bonding the inner and outer substrates 410aand 410btogether, the primary coil patterns 430awhich are formed on the upper and lower faces of the inner substrate 410aare connected together through the via holes 440 so as to form a primary coil 100. Further, the secondary coil patterns 430bof the outer substrates 410bwhich are respectively bonded to the upper and lower faces of the inner substrate 410aare connected together respectively through the via holes 440 so as to form a secondary coil 200. Thus a dual band antenna 400 is formed.

[0050] FIG. 7 schematically illustrates the manufacturing process for the dual band antenna in a third embodiment of the present invention.

[0051] A plurality of via holes 540 are formed in each of green sheets 510 which are formed by using a ceramic paste, so that coil shaving different pitches and diameters can be formed on each of the green sheets 510.

[0052] Primary coil patterns 530awhich are printed on the inner substrates 510aare connected through the via holes 540 to secondary coil patterns 530bof outer substrates 510b, thereby forming a spiral antenna 500.

[0053] Under this condition, the pattern forming means which forms the primary and secondary coil patterns 530aand 530boperates as follows. That is, a conductive paste made of Cu, Ni, Ag or Au is printed to form the patterns, and thus, when stacking the green sheets, spiral coils are formed by being electrically connected together respectively through the via holes 540.

[0054] After stacking the inner substrates 510aand the outer substrates 510bwith the primary coil patterns 530aand the secondary coil patterns 530bformed thereon, the substrates are pressed together at a pressure of 80˜120 Kg/cm²so as to form a final structure. This structure is cut into individual antennas, and they are baked at a temperature of 800˜1000° C., thereby forming a dual band antenna 500.

[0055] If the antennas of the second and third embodiments which are formed by stacking the ceramic substrates or the green sheets are applied in the hand phone or the like, the antennas do not protrude to the outside of the apparatus, and therefore, the apparatus can be miniaturized.

[0056] FIG. 8 schematically illustrates the manufacturing process for the dual band antenna in a fourth embodiment of the present invention.

[0057] As shown in this drawing, a first conductive pattern 620ais printed on a first flexible substrate in the diagonal direction, while a grounding pattern 640 is printed on the other face of the substrate in such a manner as to be connected to the first conductive pattern 620a.

[0058] Then a plurality of second conductive patterns 620bare printed on a second flexible substrate 610bat a certain inclination angle. Then the second flexible substrate 610ais wound around a cylindrical support 630 which is made of a resin, a ceramic or a magnetic material.

[0059] The second conductive patterns 620bof the second flexible substrate 610bwhich has been wound around the cylindrical support 630 form a primary coil 100. Then the first flexible substrate 610ais wound around the second flexible substrate 610b, and thus, the first conductive pattern 620abecomes a secondary coil 200.

[0060] The grounding pattern 640 which has been printed on the other face of the first flexible substrate 610ais connected to the second conductive patterns 620bof the second flexible substrate 610b, and therefore, the two sets of the conductive patterns 620aand 620bare electrically connected together, so as to form a dual band antenna 600.

[0061] Besides the connections between the two sets of conductive patterns 620aand 620bof the first and second flexible substrates 610aand 610bby utilizing the grounding pattern 640, the connections can also be carried out by soldering.

[0062] Thus the antenna 600 can be embodied in a simple manner by winding the first and second flexible substrates around the cylindrical support 630. The cylindrical support 630 may have a minimum diameter, and therefore, the miniaturization of the antenna becomes possible as well as improving the reception sensitivity.

[0063] According to the present invention as described above, the dual band antenna which receives signals through a plurality of frequency bands is improved in its reception sensitivity, is miniaturized, and is prevented from being deformed or damaged upon receiving an external impact. Further, the reception band width can be expanded.

[0064] Further, the desired dielectric constant can be obtained by arbitrarily selecting the dielectric material, and therefore, the design limitation can be minimize. Further, the conductive lines can be accurately provided, and therefore, the defect rate can be minimized.

[0065] In the above, the present invention was described based on the specific preferred embodiments and the attached drawings, but it should be apparent to those ordinarily skilled in the that various changes and modifications can be added without departing from the spirit and scope of the present invention which will be defined in the appended claims.