MOBILE COMMUNICATION ANTENNA AND MOBILE COMMUNICATION APPARATUS USING IT

Abstract: The present invention relates to an antenna equipped in a mobile telecommunication apparatus such as a portable telephone. The object of the invention is to enhance the portability and the durability of the mobile telecommunication apparatus, to provide a mobile telecommunication antenna while is improved in the mass productivity and the electrical characteristics, and to provide a mobile telecommunication apparatus employing the antenna. To achieve the object of the present invention, the mobile communication apparatus has no projecting portion of the antenna provided on a case, and the antenna is accommodated in the case. This enhances both the portability and the durability. Also, the antenna is reduced to a chip size thus improving its mass-productivity and electrical characteristics.

Description: Mobile telecommunication apparatuses such as portable telephones or pagers have rapidly been commercialized. Fig. 40 illustrates a common portable telephone as a mobile telecommunication apparatus. As shown, reference numeral 10 denotes a portable telephone, and reference numeral 11 denotes a case of it. Antenna 5 is disposed in parallel with the longitudinal direction of case 11 and extending outwardly from case 11. Antenna 5 is joined at one end with power supply 13 mounted in the case for feeding a high-frequency signal. In the figure, reference numeral 1 denotes a microphone, reference numeral 2 denotes an operation unit, reference numeral 3 denotes a display, and reference numeral 4 denotes speaker. In such a conventional construction of the portable telephone, the extending antenna declines portability as a portable telephone accordingly declines. Also, the antenna is fragile and may be easily broken by any abrupt shock, for example, in dropped down. In the manufacturing process of the portable telephones, the antenna has to be mounted to the case by manually tightening screws. The process can be hardly automated thus increasing the overall cost of manufacturing. Also, the conventional telephone construction requests the antenna and a high-frequency circuit to be electrically connected to each other by a dedicated a connecting component, which possibly claims the cost-up, causes the power loss, and thus is also unfavorable in the electrical characteristics. WO 99/03166 discloses an antenna for a portable telephone with two antenna elements being tuned to different resonant frequencies. The antenna elements are either both of meander form or both of spiral form and connected to a common feed point. In another embodiment one antenna element is of meander form and the other in form of a straight line. In all embodiments the antenna elements are connected to a common feed point. A block of moulded or dielectric material in the form of a parallelepiped is suggested to integrate or support the antenna elements. This block is located in an upper longitudinal end region of the telephone case. An additional whip antenna is connected to the antenna elements, which extends outside of the telephone casing. EP 0 777 293 A1 describes a chip antenna having multiple resonance frequencies. Two conductors are embedded in a dielectric substrate of parallelepiped form. Both conductors are electrically connected with each other, either by being connected in parallel to a common feeding point or in series to each other. The conductors are both either of meander or both of helical shape. EP 0 860 897 A1 suggests a dual band antenna for a mobile wireless device which comprises a helical antenna element and a whip antenna element. The helical antenna element is a parasitic element to the whip antenna element. EP 0 871 238 A1 relates to antenna structures realised by microstrips, having certain resonance frequencies, which are tuned close to each other, so that the operating band is substantially continuous. The strips have quarter wave lengths and are arranged in the mobile unit in lengthwise direction. EP 0 878 863 A2 suggests a single band antenna in a mobile communication apparatus. The antenna element is a non-directional chip antenna embedded in a reinforced plastic or dielectric body in close proximity to a grounded reflecting plate to provide for directivity. The object of the invention is to provide for a mobile telecommunication apparatus according to the introductory part of claim 1 as known from WO 99/03166 with reliable construction and enhanced receiving/transmitting properties. This object is solved by the features of claim 1. Preferred embodiments are referred to in the depending claims. Fig. 1 is a schematic view of a portable telephone according to Embodiment 1 of the present invention; Fig. 2 is a radiation pattern of an antenna having a radiation-conductive element of substantially 1/2 wavelength according to the same mbodiment; Fig. 3 is a radiation pattern of a conventional antenna, shown in Fig. 40, having a radiation-conductive element of substantially 1/2 wavelength; Fig. 4 is a schematic view showing the telephone according to the same embodiment in its actual use; Fig. 5 is a radiation pattern of the antenna having a radiation conductive element of substantially 1/2 wavelength in its actual use according to the same embodiment; Fig. 6 is a radiation pattern of the conventional antenna having a radiation conductive element of substantially 1/2 wavelength in its actual use; Fig. 7 is a radiation pattern of the antenna having a radiation-conductive element of substantially 1/4 wavelength according to the same embodiment; Fig. 8 is a radiation pattern of the conventional antenna having a radiation-conductive element of substantially 1/4 wavelength; Figs. 9(a) and 9(b) are a perspective view and a cross sectional view of an antenna according to Embodiment 2 of the present invention; Fig. 10 is a perspective view showing a modification of the antenna according to the same embodiment; Fig. 11 is a perspective view showing another modification of the antenna according to the same embodiment; Fig. 12 is a perspective view showing a further modification of the antenna according to the same embodiment; Figs. 13(a) and 13(b) are a perspective view and a cross sectional view showing a still further modification of the antenna according to the same embodiment; Figs. 14(a) and 14(b) are a perspective view and a cross sectional view showing a still further modification of the antenna according to the same embodiment; Fig. 15 is a perspective view showing a still further modification of the antenna according to the same embodiment; Fig. 16 is a perspective view showing a still further modification of the antenna according to the same embodiment; Fig. 17 is a perspective view showing a still further modification of the antenna according to the same embodiment; Figs. 18(a) and 18(b) are a perspective view and a cross sectional view showing a still further modification of the antenna according to the same embodiment; Figs. 19(a) and 19(b) are a perspective view and a cross sectional view showing a still further modification of the antenna according to the same embodiment; Fig. 20 is a perspective view showing a still further modification of the antenna according to the same embodiment; Fig. 21 is a perspective view showing a still further modification of the antenna according to the same embodiment; Figs. 22(a) and 22(b) are a perspective view and a cross sectional view showing a still further modification of the antenna according to the same embodiment; Figs. 23(a) and 23(b) are a perspective view and a cross sectional view showing a still further modification of the antenna according to the same embodiment; Fig. 24 is a perspective view showing a still further modification of the antenna according to the same embodiment; Fig. 25 is a perspective view showing a still further modification of the antenna according to the same embodiment; Fig. 26 is a perspective view showing a still further modification of the antenna according to the same embodiment; Figs. 27(a) and 27(b) are a perspective view and a cross sectional view showing a still further modification of the antenna according to the same embodiment; Figs. 28(a) and 28(b) are a perspective view and a cross sectional view showing a still further modification of the antenna according to the same embodiment; Fig. 29 is a perspective view of an installed antenna according to Embodiment 3 ; Fig. 30 is a perspective view showing a modification of the installed antenna according to the same embodiment; Figs. 31(a) and 31(b) are a schematic view and a partial cross sectional view showing the antenna installed into a portable telephone according to the same embodiment; Fig. 32 is a schematic view of the portable telephone in use according to the same embodiment; Fig. 33 is a perspective view showing a further modification of the installed antenna according to the same embodiment; Figs. 34(a) and 34(b) are a perspective view and a partial cross sectional view showing a further modification of the installed antenna installation according to the same embodiment; and Fig. 35 is a perspective view of another conventional antenna. Fig. 1 is a schematic view of a portable telephone according to Embodiment 1 of the present invention. Reference numeral 10 denotes a portable telephone, reference numeral 11 denotes its case. Antenna 12 having a radiation-conductive element is mounted in case 11 substantially vertical to the longitudinal direction of case 11 and not project outwardly from case 11. Antenna 12 is jointed at one end to power supply 13 mounted in case 11 for feeding a high-frequency signal. Reference numeral 1 denotes a microphone, reference numeral 2 denotes an operation unit, reference numeral 3 denotes a display, and reference numeral 4 denotes a speaker. As shown, antenna 12 is disposed in case 11 substantially orthogonal to the longitudinal direction of case 11. That results that the telephone has no projecting portion, enhances its portability, and is protected from broken.. Fig. 2 illustrates a radiation pattern of antenna 12 having a radiation-conductive element of substantially 1/2 wavelength. For comparison, Fig. 3 illustrates a radiation pattern of a conventional antenna (of which radiation-conductive element has 1/2 wavelength) disposed parallel to the longitudinal direction of the case, as shown in Fig. 35. In common, portable telephone 10 is sensitive to a vertically polarized wave along the Z-axis radiated from case 11 and a horizontally polarized wave along the Y-axis radiated from the radiation-conductive element of antenna 12. In comparison, the antenna according to this embodiment exhibits a sensitivity greater than or equal to -10 (dBd) to five different polarized waves, i.e., two in the XY plane, two in the ZX plane, and one horizontally polarized wave in the YZ plane as shown in Fig. 2. The conventional antenna exhibits a sensitivity greater than or equal to -10 (dBd) to three different polarized waves, i.e., one vertically polarized wave in the XY plane, one horizontally polarized wave in the YZ plane, and one horizontally polarized wave in the ZX plane as shown in Fig. 3. The antenna according to this embodiment works in more polarization planes, and its antenna characteristic is reduced in a declination in actual use. As an antenna at a base station for the portable telephones is disposed generally in vertical, a vertically polarized wave often reach the portable telephones or mobile communication apparatuses. The antenna according to this embodiment enables to minimize declination in the sensitivity to the vertical polarized wave in actual use. This will be explained in more detail referring to Fig. 4 where the portable telephone is positioned in actual use corresponding to an ear and a mouth of a user. As shown, portable telephone 10 in the use is tilted about 60° from the vertical, and its antenna characteristic to the vertically polarized wave may accordingly be declined. The radiation-conductive element of antenna 12 mounted in vertical to the longitudinal direction of case 11 is tilted only 30° from the vertical direction. Consequently, its antenna characteristic for the vertical polarized wave does not decline in actual use as compared with the conventional antenna, which is disposed in parallel with the longitudinal direction of the case. Fig. 5 shows a radiation pattern of the antenna of the portable telephone operated at the position shown in Fig. 4. Fig. 6 shows that of the conventional portable telephone for comparison. As shown, a pattern average gain (PAG) to a vertically polarized wave of the portable telephone according to this embodiment in actual use is about 3 (dBd) higher. Moreover, as the radiation-conductive element of antenna 12 is located at the upper end in case 11, it may hardly be covered with a hand of the user. That reduces a declination in the antenna characteristic caused by the user's body. The radiation-conductive element is located at the upper end in the case, its electrical length is set to substantially an n/2 wavelength (where n is an odd number), and consequently, a current hardly runs along the case. Accordingly, even if the hand grips the case, an impedance change of the antenna as well as an attenuation of the antenna radiation is reduced, and the antenna characteristic is favorably reduced in a declination. Also, the radiation-conductive element disposed substantially in vertical to the longitudinal direction of the case works as an antenna not only for the vertically polarized wave but also for the horizontally polarized wave. Consequently, the antenna characteristic is reduced in the declination in actual use. Fig. 7 shows an antenna radiation pattern of antenna 12 having the radiation conductive element of substantially 1/4 wavelength. For comparison, Fig. 8 shows an antenna radiation pattern of the conventional antenna (of which radiation conductive element has substantially a 1/4 wavelength) disposed in vertical to the longitudinal direction of the case. As shown in comparing these, substantially the same radiation characteristic as of the projecting antenna is obtainable even if the antenna having the radiation-conductive element is disposed in substantially vertical to the longitudinal direction of the case, and a portability of a mobile telecommunication apparatus is improved thanks to the non-projecting antenna. When the electrical length of the radiation conductive element is substantially an n/4 wavelength (where n is an odd number), a more current runs through the case. This causes the antenna impedance to be changed when the case is gripped by the hand, hence making the impedance matching difficult and making the antenna radiation unfavorable. Accordingly, the antenna characteristic may marginally be declined. On the contrary, the impedance of the antenna is close to 50Ω when the case is not touched by the hand, and thus, a matching circuit can be omitted. The fabricating process hence increases in the efficiency and decreases in the cost. The construction of antenna 12 shown in Fig. 1 will be described in more detail referring to Figs. 9 through 28. The antenna construction here is designed for transmitting and receiving signals in two different frequency bands, but not limited to it. Throughout the drawings, like components are denoted by like numerals, and their description will not be repeated. In Fig. 9, reference numeral 12 denotes an antenna. First radiation-conductive element 15 is arranged in a helical form in dielectric substrate 14 and second radiation-conductive element 16 is arranged in a zigzag, meander form on the top of or within the dielectric substrate 14 over first radiation-conductive element 15. First radiation conductive element 15 and second radiation conductive element 16 are insulated from each other while only first radiation conductive element 15 is connected to power supply terminal 13a for feeding a high-frequency signal. Second radiation conductive element 16 is fed with a high-frequency signal by an electromagnetic coupling effect with first radiation conductive element 15. This allows first radiation-conductive element 15 and second radiation-conductive element 16 to resonate at different frequencies, thus permitting to transmit and receive signals at each two different frequency, respectively. Dielectric substrate 14 is formed by laminating plural dielectric layers and assembling them to a single unit. Patterns of conductors and relevant through-holes at specific positions on specific layers are arranged to form desired shapes of first radiation conductive element 15 and second radiation conductive element 16. Other modifications of this embodiment described blow are also implemented through forming first radiation conductive element 15 and second radiation conductive element 16 of desired shapes. The first and second radiation-conductive elements may be accompanied with a third, a fourth, and more radiation-conductive elements which are disposed at different locations and electrically insulated from the first and second radiation-conductive elements. And the antenna can accordingly transmit and receive signals at a more number of frequency bands. The radiation-conductor elements are selected from helical elements and meander elements. Accordingly, while the apparatus is capable of transmitting and receiving the plural frequency bands of signals, its overall dimensions can significantly be reduced. The antennas shown in Figs. 9 through 14 commonly comprise first radiation conductive element 15 formed of a helical element connected to power supply terminal 13a for feeding a high-frequency signal, second radiation conductive element 16 formed of a meander element of zigzag shape. Those differ from each other in the relationship between positions of first radiation conductive element 15 and second radiation conductive element 16. More specifically, Fig. 9 illustrates the helical axis of helical element 15 and the zigzag direction of meander element 16 both arranged substantially in parallel with the longitudinal direction of dielectric substrate 14. Fig. 10 shows the elements are arranged substantially orthogonal to the longitudinal direction. Fig. 11 illustrates the helical axis of helical element 15 arranged substantially in parallel with the longitudinal direction of dielectric substrate 14 while the zigzag direction of meander element 16 arranged substantially orthogonal to the longitudinal direction. Fig. 12 is the reverse to that, where the helical axis of helical element 15 arranged substantially orthogonal to the longitudinal direction of dielectric substrate 14 while the zigzag direction of meander element 16 is arranged substantially in parallel with the longitudinal direction. Fig. 13 illustrates meander element 16 disposed along the center of the helical element 15 while two elements 15 and 16 are arranged as shown in Fig. 9. Fig. 14 illustrates meander element 16 located on the side of helical element 15. The antennas shown in Figs. 15 through 18 commonly comprise first radiation-conductive element 17 and second radiation-conductive element 18 both arranged of a helical shape, where only first radiation conductive element 17 is connected to power supply terminal 13a for feeding high-frequency signals. Those differ from each other in the relationship between positions of first radiation conductive element 17 and second radiation conductive element 18. More specifically. Fig. 15 shows the helical axis of first helical element 17 and the helical axis of second helical element 18 both arranged substantially in parallel with the longitudinal direction of dielectric substrate 14. Fig. 16 shows both elements arranged substantially orthogonal to the longitudinal direction. Fig. 17 shows that the helical axis of first helical element 17 is arranged substantially orthogonal to the longitudinal direction of dielectric substrate 14, and the helical axis of second helical element 18 is arranged substantially in parallel with the longitudinal direction. Fig. 18 shows that helical element 18 disposed along the center of the helical shape of helical element 17 while two elements 17 and 18 are shaped as shown in Fig. 15. The antennas shown in Fig. 19 through 22 commonly comprise first radiation conductive element 19 and second radiation conductive element 20 both arranged of a meander shape, where only first radiation conductive element 19 is connected to power supply terminal 13a for feeding a high-frequency signal. Those differ from each other in the relationship between positions of first radiation conductive element 19 and second radiation conductive element 20. More specifically, Fig. 19 shows the zigzag directions of first meander element 19 and second meander element 20 both arranged substantially in parallel with the longitudinal direction of dielectric substrate 14. Fig. 20 shows the elements are arranged substantially orthogonal to the longitudinal direction. Fig. 21 shows that the zigzag direction of first meander element 19 is arranged substantially in parallel with the longitudinal direction of dielectric substrate 14, and the zigzag direction of second meander element 20 is arranged substantially orthogonal to the longitudinal direction. Fig. 22 shows two meander elements 19 and 20 disposed orthogonal to the bottom of dielectric substrate 14 while two elements 19 and 20 are shaped as shown in Fig. 19. The antennas shown in Figs. 23 through 28 commonly comprise first radiation-conductive element 21 formed of a zigzag, meander shape connected to power supply terminal 13a for feeding a high-frequency signal and second radiation-conductive element 22 is formed of a helical shape. Those differ from each other in the relationship between positions of first radiation-conductive element 21 and second radiation-conductive element 22. More specifically, Fig. 23 shows the zigzag direction of meander element 21 and the helical axis of helical element 22 both arranged substantially in parallel with the longitudinal direction of dielectric substrate 14. Fig. 24, like Fig. 9, shows both arranged substantially in orthogonal to the longitudinal direction. Figs. 23 and 24 where power supply terminal 13a is connected to meander element 21 differs from Figs. 9 and 10 where power supply terminal 13a is connected to helical element 15. Fig. 25 shows that the zigzag direction of meander element 21 is arranged substantially in parallel with the longitudinal direction of dielectric substrate 14, and the helical axis of helical element 22 is arranged substantially in orthogonal to the longitudinal direction. Fig. 26, in reverse to that, shows that the zigzag direction of meander element 21 is arranged substantially in orthogonal to the longitudinal direction of dielectric substrate 14, and the helical axis of helical element 22 is arranged substantially in parallel with the longitudinal direction Figs. 25 and 26 where power supply terminal 13a is connected to meander element 21 differs from Figs. 11 and 12 where power supply terminal 13a is connected to helical element 15. Fig. 27 illustrates meander element 21 disposed in helical element 22 while elements 21 and 22 are disposed as shown in Fig. 23. Fig. 28 illustrates meander element 21 disposed on the side of helical element 22 in the same construction. The installation of antenna 12 shown in Fig. 1 will be specifically described referring to Figs. 29 through 34. The installation of the antenna operable to transmit and receive signals in two different frequency bands, respectively, but is not limited to that. Throughout the drawings, like components are denoted by like numerals, and their description will not be repeated. In Fig. 29, reference numeral 12 denotes an antenna. In the antenna, first radiation-conductive element 23 is formed of a helical shape on the surface of core member 33 made of dielectric material, magnetic material, or insulating resin material, and second radiation-conductive element 24 is formed of a zigzag meander shape insulated from first radiation-conductive element 23. Also, only first radiation conductive element 23 is connected to power supply terminal 13a for feeding a high-frequency signal. Matching circuit 14 is connected between power supply terminal 13a and power supply 13. Matching circuit 14 may comprise chip capacitors, chip inductors, or reactance elements, e.g. a circuit pattern on printed circuit board 8. Matching antenna 12 with power supply 13 reduces the power loss of reflections. Core member 33 made of a dielectric material shortens its electrical length due to a wavelength-shortening effect on the dielectric material thus contributing to the smaller size of antenna 12. Antenna 12 having core member 33 made of magnetic material, antenna 12 is favorable for low-frequency signals. In case that core member 33 is made of an insulating resin material, antenna 12 may be fabricated at higher efficiency. First radiation conductive-element 23 and second radiation-conductive element 24 are placed in advance at such locations as to realize a desired antenna characteristic and are encapsulated with the resin material by mold forming. First and second radiation-conductive elements 23, 24 may be shaped by pressing process. The whole manufacturing process can accordingly be easily automated with high productivity. The relationship between positions of first radiation-conductive element 23 and second radiation-conductive element 24 may be modified for controlling the strength of electromagnetic coupling. This facilitates to adjust the impedance in the respective frequency band. Also, the antenna construction according to this embodiment is favorable for modifying the relationship between positions of the first and second radiation conductive elements. The installation of antenna 12 will now be explained. Antenna 12 comprises three mounting terminals 25 formed on the bottom and sides thereof for being easily mounted on printed circuit board 8. Power supply terminal 13a is also formed over the bottom and a side of antenna 12. On the other hand, on printed circuit board, mounting lands 26 and power supply land 27 are formed on the corresponding four locations. Antenna 12 is securely soldered at the four locations, together with other components, to printed circuit board 8 by an automatic mounting technique. Fig. 30 is a perspective view explaining a modification of the antenna installation. As shown, power supply terminal 28a connected to first radiation-conductive element 23 is formed on one end of core member 33, and mounting terminal 29a is formed on the other end. Power supply jig 28b and mounting jig 29b corresponding to the terminals, respectively, are provided on printed circuit board 8. The antenna is mounted, power supply terminal 28a and mounting terminal 29a are put in and fixed to jigs 28b and 29b, respectively. Consequently, antenna 12 is securely mounted by employing a simple arrangement, prevented from exposing to high temperatures in the reflow process, and thus, made of low fusing point material. And its characteristic is thus hardly declined. Fig. 31 illustrates a schematic plan view and a partially cross sectional view of a portable telephone to which the antenna is installed. Fig. 32 is a schematic view illustrating an example of the actual use of the portable telephone. As shown, antenna 12 is mounted at the upper end on printed circuit board 8 embedded in case 11 of portable telephone 10. More specifically, antenna 12 is mounted on the opposite side to speaker 4 of printed circuit board 8 so that the antenna is distanced from head 6 of the user as much as possible when speaker 4 is put to the ear during his/her talking. This reduces the power loss caused by the influence of head 6 and thus maintains the antenna radiation characteristics. This also reduces an unfavorable influence by holding case 11 with a hand. Antenna 12 can locate far from an interruptive object, e.g. shield cover 9 for electrically shielding a high-frequency circuit or grounding patterns formed on printed circuit board 8. This reduces an electrical coupling with the object, the power loss caused by the electrical coupling, and thus declination of the antenna characteristics. Fig. 33 is a perspective view illustrating another modification of the antenna installation. As shown, power supply terminal 34 connected to first radiation-conductive material 31 is formed on one end of the surface of core member 33 having a round shape in cross section thereof, and mounting terminal 37 is formed on the other end. Each terminal is designed so as to hold printed circuit board 8. Printed circuit board 8 has an opening formed therein operable to accommodate antenna 12. Power supply lands 36 and mounting lands 37 corresponding respectively to power supply terminal 34 and mounting terminal 35 are formed on both sides of printed circuit board 8. Power supply terminal 34 and mounting terminal 35 are soldered to their corresponding lands 36 and 37 so that antenna 12 can be securely fixed to printed circuit board 8. For accommodating antenna 12, the opening formed in printed circuit board 8 according to this embodiment may be replaced by a notch of the same size provided in the upper end of printed circuit board 8. Also, the mounting terminal and the mounting land are not limited to one pair but two or more pairs so as to fix the antenna more securely. Fig. 34 is a perspective view showing a further modification of the antenna installation. As shown, power supply terminal 34 connected to first radiation-conductive material 31 is provided on one end region of the surface of core member 33 having a round shape in cross section thereof, and three mounting terminals 35 are provided on the remaining region with an equal interval. Each terminal is designed so as to hold printed circuit board 8. Power supply lands 36 and mounting lands 37 corresponding to power supply terminal 34 and mounting terminals 35 respectively are provided on both sides of printed circuit board 8. Power supply terminal 34 and mounting terminals 35 are soldered to corresponding lands 36 and 37 so as to fix the antenna to printed circuit board 8 securely. The arrangements shown in Figs. 33 and 34 permit the space in upper portion of case 11 to be used effectively, and the antenna characteristic is improved. As set forth above, the antenna according to the present invention is mounted in substantially vertical to the longitudinal direction of a case of a mobile telecommunication apparatus, thus eliminating an undesired projecting portion on the case. This improves the portability of the mobile telecommunication apparatus, and minimizes its broken-down at any accident such as dropping down. Also, this allows the antenna to function for not only vertically polarized waves but also horizontally polarized waves to the case hence minimizing a declination in the antenna characteristic. Moreover, the antenna can be reduced to a chip size thus improving its mass-productivity and the electrical characteristics.

Claims: Mobile telecommunication reception and transmitting apparatus, as a mobile telephone, operable in two different frequency bands, comprising: a case (11) with an antenna embedded within the case (11) and located in an upper longitudinal end region of the case (11), the antenna comprising a first radiation-conductive element (15 or 16) being connected to a power supply terminal (13a) with its one end and its other end being open, the power supply terminal being connected to a high frequency transmitter/receiver circuit arranged within the case, a second radiation-conductive element (16 or 15) having two ends, both radiation-conductive elements being adapted to resonate at different of the two frequency bands, one of the two radiation-conductive elements having a meander shape, both radiation-conductive elements being electromagnetically coupled to each other, characterised in that, the other of the two radiation-conductive elements having a helical shape, the second of the two radiation-conductive elements has its two ends open to be electrically isolated from the other radiation-conductive element. Apparatus according to claim 1, characterised in that , the longitudinal extensions of the two radiation-conductive elements (15, 16) are arranged either in parallel or orthogonal to each other. Apparatus according to claim 1 or 2, characterised in that , the two radiation-conductive elements (15, 16) are integrated in a resin-molded or dielectric body (12, 14). Apparatus according to claim 3, characterised in that , the body (12, 14) is of parallelepiped shape and arranged in the case (11) with its longitudinal extension perpendicular to the longitudinal extension of the case. Apparatus according to claim 3, characterised in that , the body (12, 14) is of cylindrical shape and arranged in the case (11) with its longitudinal extension perpendicular to the longitudinal extension of the case. Apparatus according to one of claims 3 - 4, characterised in that , the meander shape radiation-conductive element is arranged on a surface of the body (12, 14). Apparatus according to one of claims 3 to 6, characterised in that , the power supply terminal (13a) is formed on the body (12, 14). Apparatus according to one of claims 1 - 7, characterised in that , the body (12, 14) is surface-mounted on a printed circuit board (8) by the power supply terminal (13a). Apparatus according to claim 5, characterised in that , the body (12, 14) projects from both sides of the printed circuit board (8). Apparatus according to any of claims 1 - 8, characterised in that , there is provided a third radiation-conductive element, being electrically isolated from the other two radiation-conductive elements (15, 16).

Inventors: FUKUSHIMA SUSUMU, IGUCHI AKIHIKO, SATOH YUKI, YUDA NAOKI, FUKUSHIMA, SUSUMU, IGUCHI, AKIHIKO, SATOH, YUKI, YUDA, NAOKI
Applicants: MATSUSHITA ELECTRIC IND CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Application year: 2000
Main classification: H01Q1
IPC codes: H01Q21, H01Q1, H01Q5