BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The present invention relates to mobile communication apparatuses having a chip antenna
in them for use in mobile communication and in a local area network (LAN).
2. Description of the Related Art
[0002] In a portable telephone 50, which is an example of a conventional mobile communication
apparatus, as shown in Figs. 10 and 11, a nondirectional whip antenna 51 is protrusively
mounted at the upper part of a portable telephone body 52 and an electric wave is
transmitted and received with the use of this whip antenna 51.
[0003] In the portable telephone, which is one of conventional communication apparatuses,
however, since the whip antenna is nondirectional, a transmitted electric wave is
affected by the person who is holding the portable telephone during use and therefore
antenna characteristics deteriorate. Especially in a high-power portable telephone,
a person using it greatly affects its antenna characteristics.
[0004] To reduce the effects of the person who is holding the portable telephone, the whip
antenna can be mounted, for example, at the lower part of the portable telephone body;
however, since the whip antenna protrudes near the mouth of the person, the antenna
may be an obstacle during communication.
SUMMARY OF THE INVENTION
[0005] The present invention is made to solve such problems. Accordingly, it is an object
of the present invention to provide a mobile communication apparatus which prevents
transmitted electric waves from receiving the effects of a person who is holding the
apparatus and which is configured such that its antenna is not an obstacle during
communication.
[0006] The object of the present invention is achieved through the provision of a mobile
communication apparatus including a chip antenna provided with: a base member made
from at least one of a dielectric material and a magnetic material, at least one conductor
formed at at least one of the inside and a surface of the base member, and at least
one electric power supply terminal provided on a surface of the base member in order
to apply a voltage to the conductor; and a body for accommodating the chip antenna
within its interior, wherein the chip antenna is disposed at a place in the body where
an electric wave used for transmission and receiving is not significantly affected
adversely.
[0007] According to the mobile communication apparatus described above, an electric wave
used for transmission and receiving is prevented from being adversely affected by
disposing the chip antenna at a position in the portable telephone body where the
electric wave is unlikely to receive the effects of a person who is using the mobile
communication apparatus. Therefore, the deterioration of the antenna characteristics
during transmission and receiving caused by the effects of the person who is using
the telephone can be reduced.
[0008] Since the chip antenna is disposed inside the portable telephone body, the antenna
is not an obstacle during communication.
[0009] In the mobile communication apparatus, the chip antenna may be disposed at a place
which is positioned at the lower part of the body during use.
[0010] According to the mobile communication apparatus described above, since the chip antenna
is disposed at a portion located at the lower part of the body during use, the deterioration
of the antenna characteristics during transmission and receiving caused by the effects
of the person who is using the telephone can be further reduced.
[0011] According to a mobile communication apparatus of the present invention, a transmitted
electric wave can be prevented from being adversely affected by disposing the chip
antenna at a place in the body where the transmitted electric wave is unlikely to
receive the effects of a person who is holding the apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Fig. 1 is a partially transparent elevation of a portable telephone, which is an
example of a mobile communication apparatus according to a first embodiment of the
present invention.
[0013] Fig. 2 is a partially transparent side view of the mobile communication apparatus
shown in Fig. 1.
[0014] Fig. 3 is a transparent perspective view of a chip antenna which can be used in a
mobile communication apparatus of the present invention.
[0015] Fig. 4 is an exploded perspective view of the chip antenna shown in Fig. 3.
[0016] Fig. 5 is a transparent perspective view of a modification of the chip antenna shown
in Fig. 3.
[0017] Fig. 6 is a transparent perspective view of another modification of the chip antenna
shown in Fig. 3.
[0018] Fig. 7 is a chart indicating the antenna gain of the mobile communication apparatus
shown in Fig. 1.
[0019] Fig. 8 is a partially transparent elevation of a portable telephone, which is an
example of a mobile communication apparatus according to a second embodiment of the
present invention.
[0020] Fig. 9 is a partially transparent side view of the mobile communication apparatus
shown in Fig. 8.
[0021] Fig. 10 is an elevation of a conventional mobile communication apparatus.
[0022] Fig. 11 is a side view of the mobile communication apparatus shown in Fig. 10.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] As examples of a mobile communication apparatus of the present invention, portable
telephones according to embodiments will be described below by referring to the drawings.
[0024] Fig. 1 and Fig. 2 are a partially transparent elevation and a partially transparent
side view of a mobile communication apparatus according to a first embodiment of the
present invention. In Figs. 1 and 2, a portable telephone 10 includes a portable telephone
body 14 made from, for example, plastic having a receiver 11, a transmitter 12, and
dial keys 13, and a chip antenna 17 which is mounted on a circuit board 15 secured
at the inside of the portable telephone body 14 and which is electrically connected
to an RF section 16 provided on the circuit board 15 in the portable telephone 10
with a transmission line (not shown) on the circuit board 15. The chip antenna 17
is disposed at a place where a transmitted electric wave is unlikely to receive the
effects of a person who is holding the portable telephone 10, for example, near the
transmitter 12.
[0025] Even when the chip antenna 17 of a nondirectional type is used in the portable telephone
10 configured as described above, since the emission path of an electric wave transmitted
from the chip antenna 17 is away from a person who is holding the portable telephone
10, the transmitted electric wave is unlikely to receive the effects of the person
and the antenna characteristics of the chip antenna 17 are prevented from deteriorating.
[0026] The chip antenna 17 is formed, for example, by a conductor 19 helically wound in
the longitudinal direction of a rectangular-parallelepiped base member 18 and disposed
in the inside of the member 18, as shown in Fig. 3 and Fig. 4. The base member 18
is made from laminated rectangular sheet layers 18a to 18c which are made from a dielectric
material having barium oxide, aluminum oxide, and silica as main components. Among
these layers, on surfaces of the sheet layers 18b and 18c, straight or almost L-shaped
electrically conductive patterns 19a to 19h made from copper or a copper alloy are
formed by printing, deposition, bonding, or plating. Via holes 20 are also provided
for the sheet layer 18b in the thickness direction. By laminating the sheet layers
18a to 18c and connecting the electrically conductive patterns 19a to 19h with the
via holes 20, winding cross sections perpendicular to a winding axis C become rectangles
and the helically wound conductor 19 is formed.
[0027] One end of the conductor 19 (one end of the electrically conductive pattern 19a)
is led to a surface of the base member 18 to form an electric power supply section
21 and is connected to an electric power supply terminal 22 provided on a surface
of the base member 18 in order to apply a voltage to the conductor 19. The other end
of the conductor 19 (one end of the electrically conductive pattern 19h) forms a free
end 23 at the inside of the base member 18.
[0028] Fig. 5 and Fig. 6 are transparent perspective views of a modification of the chip
antenna 17 shown in Fig. 3. A chip antenna 171 shown in Fig. 5 includes a rectangular-parallelepiped
base member 181, a conductor 191 helically wound in the longitudinal direction of
the base member 181 along surfaces of the base member 181, and an electric power supply
terminal 221 used for applying a voltage to the conductor 191 and provided on surfaces
of the base member 181. One end of the conductor 191 is connected to the electric
power supply terminal 221 on a surface of the base member 181. The other end of the
conductor 191 forms a free end 231 on a surface of the base member 181. In this case,
since the conductor can be easily formed helically on surfaces of the base member
by printing or other methods, the manufacturing process of the antenna can be simplified.
[0029] A chip antenna 172 shown in Fig. 6 includes a rectangular-parallelepiped base member
182, a conductor 192 formed in a meander shape on a surface of the base member 182,
and an electric power supply terminal 222 used for applying a voltage to the conductor
192. One end of the conductor 192 is connected to the electric power supply terminal
222 on a surface of the base member 182. The other end of the conductor 192 forms
a free end 232 on a surface of the base member 182. In this case, since the meander-shaped
conductor is formed only on one main surface of the base member, the base member can
be made to a low profile, and thereby the chip antenna can also be made to a low profile.
The meander-shaped conductor may be formed inside the base member.
[0030] An antenna gain in a case when the chip antenna 17 is disposed near the transmission
section 12 in the portable telephone body 14 as shown in Fig. 1 is compared with an
antenna gain in a case when the whip antenna 50 is protrusively mounted at the upper
section of the portable telephone 51. Fig. 7 shows a comparison result. In Fig. 7,
a solid line indicates an antenna gain in the present embodiment, and a dotted line
indicates an antenna gain in the conventional case. Point A indicates the position
of the portable telephones 10 and 50, and point B indicates the position of a person
who is holding the telephones.
[0031] It is understood from the result that, in the portable telephone according to the
present embodiment, the antenna gain is substantially constant in the range of 0 degrees
to 360 degrees and the person who is holding the telephone does not affect the antenna
gain.
[0032] In contrast, the antenna gain of the conventional portable telephone greatly decreases
near a person who is holding the telephone. This indicates that a transmitted electric
wave receives the effects of the person.
[0033] As described above, in the first embodiment, a transmitted electric wave is prevented
from being adversely affected by disposing the chip antenna near the transmission
section at the lower section of the portable telephone, which is a position in the
portable telephone where a transmitted electric wave is unlikely to receive the effects
of a person who is holding the telephone. Therefore, the deterioration of the antenna
characteristics caused by the effects of a person who is holding the telephone during
transmission and receiving can be reduced.
[0034] Since the chip antenna is disposed inside the portable telephone body, the antenna
is not an obstacle during communication.
[0035] Fig. 8 and Fig. 9 are a partially transparent elevation and a partially transparent
side view of a mobile communication apparatus according to a second embodiment of
the present invention. In Figs. 8 and 9, a portable telephone 30 is equipped with
a cover 32 rotatably connected to the lower part of a portable telephone body 14 through
a hinge section 31. A chip antenna 17 mounted on a circuit board 33 is disposed at
a tip of the cover 32. This chip antenna 17 is electrically connected with a lead
(not shown) to the RF section 35 of the portable telephone 30 provided on a circuit
board 34 secured to the inside of the portable telephone body 14. In this case, the
tip of the cover 32 is used as a portion where a transmitted electric wave is unlikely
to receive the effects of a person who is holding the telephone. With the cover 32
being opened, dial keys 13 are pressed to use the portable telephone 30.
[0036] As described above, in the second embodiment, by disposing the chip antenna at the
tip of the cover in the portable telephone, where a transmitted electric wave is unlikely
to receive the effects of a person who is holding the telephone, the distance between
the person who is holding the telephone and the chip antenna can be extended during
transmission and receiving. Therefore, in addition to the same advantages as in the
first embodiment, the deterioration of the antenna characteristics during transmission
and receiving caused by the effects of the person who is holding the telephone can
be further reduced.
[0037] In the first and second embodiments, the base member of the chip antenna is made
from a dielectric material. The material of the base member is not limited to a dielectric
material and may be a magnetic material such as ferrite, or a combination of a dielectric
material and a magnetic material.
[0038] In the above embodiments, a single conductor is used. A plurality of conductors disposed
in parallel to each other may be used. In this case, a plurality of resonant frequencies
can be provided according to the number of conductors, and one antenna can handle
multiple bands.
[0039] In the above embodiments, the conductor is formed inside the base member of the chip
antenna or on a surface of the base member. Conductive patterns may be wound on a
surface and in the inside of the base member to form the conductor.
1. A mobile communication apparatus (10; 30) comprising:
an apparatus body (14) having a transmitter (12) and a receiver (11), and a chip antenna
(17; 171; 172) in said apparatus body, said chip antenna (17; 171; 172) comprising:
a base member (18; 181; 182) made from at least one of a dielectric material and a
magnetic material;
at least one conductor (19; 191; 192) formed at least at one of the inside and a surface
of said base member (18; 181; 182); and at least one electromagnetic signal supply
terminal (21; 221; 222) on a surface of said base member for applying an electromagnetic
signal voltage to said conductor;
wherein said chip antenna (17; 171; 172) is disposed at a place in said apparatus
body (14) such that a location of said chip antenna (17; 171; 172) is closer to a
location of said transmitter (12) than to a location of said receiver (11).
2. A mobile communication apparatus (10) according to claim 1, wherein said chip antenna
(17; 171; 172) is disposed at a lower part of said apparatus body (14) during use.
3. A mobile communication apparatus (30) according to claim 2, wherein said apparatus
body (14) comprises a cover (32) which is extendable away from a main part of the
apparatus body (14) during use, said chip antenna (17; 171; 172) being disposed at
said cover.
4. A mobile communication apparatus (10; 30) comprising:
an apparatus body (14) having a transmitter (12) and a receiver (11), and a chip antenna
(17; 171; 172) in said apparatus body (14), said chip antenna comprising:
a base member (18; 181; 182) made from at least one of a dielectric material and a
magnetic material;
at least one conductor (19; 191; 192) formed at least at one of the inside and a surface
of said base member; and at least one electromagnetic signal supply terminal on a
surface of said base member (18; 181; 182) for applying an electromagnetic signal
voltage to said conductor (19; 191; 192);
wherein said chip antenna (17; 171; 172) is disposed at a lower part of said apparatus
body (14) during use.
5. A mobile communication apparatus (30) according to claim 4, wherein said apparatus
body (14) comprises a cover (32) which is extendable away from a main part of the
apparatus body during use, said chip antenna being disposed at said cover.