JPH10200318A - Antenna element for portable communication terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the external dimension of an antenna element to a minimum and to enable addition to the case of a portable communication terminal in good appearance by providing a 1nd conductor, with which one terminal of 1st conductor is successively linked to the other terminal, and forming these 1st and 2nd conductors through a substrate onto a coil. SOLUTION: An antenna element 10 for a portable communication terminal is provided with a substrate 11, 1st conductor 21 and 2nd conductor 22 to be arranged on the substrate 11. The 1st conductors 21 are parallelly arranged at the interval of a prescribed pitch d1 on the surface of the substrate 11. The 2nd conductor 22 successively links one terminal of each 1st conductor 21 to the other terminal respectively through holes 23 at both terminals. Therefore, the 1st and 2nd conductors 21 and 22 forms a coil 20 having length d2 and width d3 as a whole through the substrate 11. Thus, since the 1st and 2nd conductors 21 and 22 can form the coil 20 through the substrate 11, the external dimension can be minimized as a whole and the addition to the case of a portable communication terminal is enabled in extremely good appearance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can be suitably used for portable communication terminals such as portable telephones, simple portable telephones (so-called PHS portable telephones, the same applies hereinafter), pagers, portable information processing terminals and the like. The present invention relates to an antenna element for a mobile communication terminal.

[0002]

2. Description of the Related Art The mainstream of antennas used in portable communication terminals is rod antennas which are built in a case constituting the portable communication terminal so as to be extendable and contractible. Also, a helical antenna that always projects short outside the case is known.

[0003]

According to the prior art, the rod antenna needs to be pulled out of the case for a long time each time it is used. Therefore, the operation is troublesome, and the rod antenna is easily damaged by a slight external force. There was a problem that there was a danger of eye contact during use. Also, since the helical antenna is configured by protecting the antenna element made of an air-core coil with a cover material such as silicone rubber, the outer diameter tends to be large,
If it was fixed by protruding from the case, the problem of poor overall appearance was inevitable.

In view of the above-mentioned problems in the prior art, an object of the present invention is to minimize the external dimensions by forming a coil using first and second conductors on a substrate, thereby providing a portable communication terminal case. An object of the present invention is to provide an antenna element for a portable communication terminal that can be attached in a good appearance.

[0005]

In order to achieve the above object, the present invention comprises a substrate, a first conductor arranged in parallel on the surface of the substrate at a predetermined pitch, and a first conductor on the back surface of the substrate. A second conductor that sequentially connects one end of the first conductor to the other end, and the gist is that the first and second conductors form a coil via a substrate.

[0006] The first and second conductors can be connected via a through hole formed in the substrate.

[0007] However, the coil is formed by dividing on a plurality of layers of substrates, or a plurality of sets of different lengths are formed on the substrate at the same or different positions in the same direction, or on the substrate. In, a plurality of sets having the same length can be formed at different positions in a direction perpendicular to each other.

The substrate may be protected by a cover material. At this time, the substrate may be provided with a through hole.

[0009] Further, a fixing engagement projection can be protruded from the cover member.

[0010]

According to the structure of the present invention, the first conductors are arranged in parallel at a predetermined pitch on the front surface of the substrate, and the second conductor is connected to one end of each first conductor on the back surface of the substrate. Connect to the other end in order. Therefore, the first and second conductors can form a coil of a predetermined length as a whole on both surfaces of the substrate, and can resonate at a predetermined use frequency. However, the first and second conductors at this time form a coil having a length equivalent to an odd multiple of λ / 4 with respect to the wavelength λ of the operating frequency, and are combined with an electrically sufficiently large ground plane. It shall be used as a monopole antenna.

When the first and second conductors are connected via the through hole, the first and second conductors are connected at once through the through hole plating process to form a coil.

When a coil is formed by being divided on a plurality of stacked substrates, the coil has a broad resonance characteristic and can easily realize a wide band characteristic. However, for the coil at this time, for example, by using three substrates, half of the base side is formed on an intermediate substrate,
The half of the tip side can be formed overlapping on the upper and lower substrates.

If a plurality of sets of coils having different lengths are formed at the same position in the same direction on the substrate, each coil resonates at a different frequency, and is optimal for, for example, two frequencies for transmission and reception. Can be used in the state.
At this time, the coils can be formed at the same position by shifting the positions in the axial direction by １ ／ pitch from each other.

If a plurality of sets of coils having different lengths are formed at different positions in the same direction, the coils can resonate at different frequencies to achieve a wider band. For example, as in a portable telephone or a simple portable telephone, etc. In a device used close to the body, it is possible to easily cover fluctuations in the resonance frequency due to the body effect.

If a plurality of sets of coils having the same length are formed at different positions in the perpendicular direction, it is possible to satisfactorily receive and transmit both horizontally polarized waves and vertically polarized waves. An array antenna element can be configured.

When protecting the substrate with a cover material,
The coil formed on the substrate can be effectively protected from mechanical external force via the cover material. The cover material at this time is, for example, silicone rubber,
It is assumed that a synthetic resin material having appropriate elasticity and good radio wave transmittance is used, and is integrally formed into a predetermined external shape so as to cover the entire substrate except for the terminals.

If a through hole is provided in the substrate, a part of the cover material is also filled in the through hole during molding, and the integrity with the substrate can be enhanced. In addition, if the cover member is provided with the engagement protrusion, the whole can be easily fixed to the case of the portable communication terminal or the like via the engagement protrusion.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

Antenna element 10 for portable communication terminal
Is a substrate 11 and first conductors 2 arranged on the substrate 11
, And the second conductors 22, 22 (FIG. 1).

The substrate 11 is a double-sided printed circuit board having a good high frequency characteristic such as a fluororesin type or an epoxy resin type. A large-diameter through hole 11a is formed at one end of the substrate 11, and a small-diameter through hole 11a is formed at the other end of the substrate 11.
b is formed. The substrate 11 is formed in a rectangular shape having a length d4 and a width d5.

Are arranged in parallel at a predetermined pitch d1 on the surface of the substrate 11 (FIGS. 1 and 2). The second conductors 22, 22,... Connect one end of each first conductor 21 to the other end in turn via the through holes 23, 23 at both ends, and accordingly, the first and second conductors 21, 21,. , 22, 22, ... are the substrates 1
1, a coil 20 having a length d2 and a width d3 is formed as a whole. However, the first first conductor 21 on the base end side of the coil 20 is connected to the through hole 11a of the substrate 11 via the connection line 24a. Also, the coil 20
It bypasses the through hole 11b of the substrate 11 via another connection line 24b. That is, the length d2 of the coil 20 is
1b is divided into a long base end portion d2a and a short front end portion d2c via a portion d2b, and d2 = d2a + d2b + d2c.
It has become.

The through holes 11a of the substrate 11 are provided with terminals 12 made of a double-sided printed board (FIGS. 1 and 3). The terminal 12 is connected to the through-hole 11
It is inserted into a and soldered to the substrate 11 by soldering, and a through hole 12b is formed at the tip.
However, the coaxial cable 1 for the feeder is provided in the through hole 12b.
The base plate 14 is connected to the shield jacket 13b of the coaxial cable 13 by inserting and soldering the three core wires 13a.

The antenna element 10 includes a cover material 15
(FIGS. 1 and 4). Cover material 15
The terminal 12 is exposed to the outside and integrally molded into a predetermined shape, and an engaging projection 15a is provided on the lower surface of the distal end. However, the engagement rib 1 is provided at the base of the engagement protrusion 15a.
5a1 are formed. The cover material 15 is also filled in the through holes 11b of the substrate 11.

The antenna element 10 can be compactly attached to, for example, a case C of a mobile phone via the cover member 15 (FIGS. 4 and 5). However, the case C is constituted by attaching a cover C1 to a main body C2, and the antenna element 10 is provided on the inner surface of the distal end portion of the cover C1. A transmitter C1a is incorporated at the tip of the opening / closing lid C1, and various operation keys including numeric keys C2a, C2a, etc., a display C2b,
A receiver C2c and the like are incorporated. In the antenna element 10, the terminal 12 and the engaging projection 15a are inserted into the mounting holes C1b and C1c of the opening / closing lid C1, respectively.
It is fixed via a1. The coaxial cable 13 attached to the antenna element 10 is connected to a communication unit (not shown) in the main body C2, and the main plate 14 is incorporated in the opening / closing lid C1.

The antenna element 10 has a length d4 = 2
A pitch d1 = 0.5 m on an epoxy resin substrate 11 having a thickness of 7 mm, a width d5 = 4.5 mm and a thickness of 0.5 mm.
m, d2a = 0.5 × 38 = 19 mm, d2b = 2 mm, d
2c = 0.5 × 2 = 1 mm, length d2 = d2a + d2b + d2c
When the coil 20 having a width of 22 mm and a width d3 of 3.1 mm was formed and operated as a monopole antenna together with the ground plane 14, the frequency characteristics shown in FIG. 6 were obtained. However, FIG.
The horizontal axis indicates the frequency f (MHz), and the vertical axis indicates the voltage standing wave ratio SWR. In addition, this antenna uses a received radio wave S composed of horizontal polarization and vertical polarization for each installation direction.
The horizontal directional characteristics as shown by the solid lines in FIGS. 7 to 9 with respect to h and Sv. However, in these figures, the alternate long and short dash line is the comparison characteristic of the rod antenna RD, and the attached schematic diagram shows the 0 ° direction at which the received radio waves Sh and Sv arrive. In the radial direction, the reception voltage V (dBμV)
It is. That is, the antenna element 10 can realize good operating characteristics comparable to the rod antenna RD.

[0026]

[Other Embodiments] The antenna element 10 has a terminal 1
2 may be formed as a part of the substrate 11 (FIG. 10).
The cover member 15 is formed in a vertically long tapered dome shape, and is fixed to the surface of the case C so as to protrude. Also,
Through holes 11b, 11b are formed in the upper and lower portions of the substrate 11, and one end of the coil 20 on the terminal 12 side is led out to the terminal 12 via a connecting wire (not shown). Therefore,
The antenna element 10 can operate as a monopole antenna by inserting and connecting the core wire 13a of the coaxial cable 13 into the through hole 12b of the terminal 12 and connecting the ground plate 14 to the shield jacket 13b.

The antenna element 10 can be formed by dividing the coil 20 on a plurality of substrates 11, 11,... The coil 20 is １ ／ of the whole
Is formed on the intermediate substrate 11, and the tip side 20 b corresponding to the other half is the upper and lower substrates 1.
1 and 11 (FIG. 11A,
(B)), the base side 20a and the front end sides 20b, 20b are connected via connection lines 24c passing through the substrates 11, 11,.... The substrates 11, 11... Can be integrally finished by closely contacting and layering (FIG. (C)). However, one end of each substrate 11 has a through hole 12b
Are integrally formed, and the terminals 12, 12... Connecting one end of the coil 20a through a continuous wire 24a are provided with:
It is assumed that the core wires 13a of the coaxial cables 13 are commonly connected.

When the dimensions of each part of the antenna element 10 of FIG. 11 are substantially the same as those of FIG.
The following frequency characteristics were obtained. That is, the antenna element 10 includes the coil 20 and the plurality of substrates 11, 11.
.. Can be broadened to broaden the resonance characteristics and broaden the band.

In the antenna element 10, a plurality of sets of coils 20 having different lengths may be formed at the same position on the substrate 11 in the same direction (FIG. 13). Coil 2
0 and 20 are led out to the common terminal 12 via the connection line 24a. Since the coils 20 and 20 resonate at different frequencies, the antenna element 10 can realize a double peak frequency characteristic as a whole (FIG. 14).

In the antenna element 10, a plurality of sets of coils 20, 20... Having different lengths may be formed at different positions in the same direction on the substrate 11 (FIG. 15). Substrate 1
1 have different resonance frequencies, and therefore, the antenna element 10 exhibits a multi-peak broadband frequency characteristic as a whole (FIG. 1).
6). When a single coil antenna element is used in, for example, a simple cellular phone, the resonance frequency greatly varies depending on the use state (FIG. 17). However, the antenna element 10 of FIG. Can be effectively covered. However, the solid line, the one-dot chain line, and the two-dot chain line in FIG. 3 shows an example of each frequency characteristic when left on a desk.

In the antenna element 10, a plurality of sets of coils 20 having the same length may be formed at different positions in the direction perpendicular to each other on the substrate 11 (FIG. 18).
The antenna element 10 is connected via the coils 20 and 20,
As a whole, it operates as a so-called polarization-synthesizing array-type antenna element, and it is possible to realize substantially uniform horizontal directivity for both received radio waves Sh and Sv composed of horizontally polarized waves and vertically polarized waves (FIG. 19). ). However, the solid line in FIG. 19 shows the characteristic for the received radio wave Sv composed of the vertically polarized wave, and the one-dot chain line shows the characteristic for the received radio wave Sh composed of the horizontal polarization.

[0032]

As described above, according to the present invention, the first conductor arranged on the front surface of the substrate and the second conductor connecting one end of each first conductor to the other end on the back surface of the substrate are sequentially arranged. By providing the conductor, the first and second conductors can form a coil via the substrate, so that the overall external dimensions are minimized and the first and second conductors are attached to the case of the portable communication terminal in a very well-formed manner. In addition to this, there is an excellent effect that good operation characteristics comparable to those of the conventional antenna can be realized.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of the entire configuration.

FIG. 2 is an explanatory view of a main part of a coil.

FIG. 3 is an enlarged sectional view of a main part of FIG. 1;

FIG. 4 is a view corresponding to a longitudinal section of FIG. 1;

FIG. 5 is an explanatory view of a use state.

FIG. 6 is an operating characteristic diagram (1).

FIG. 7 is an operation characteristic diagram (2).

FIG. 8 is an operation characteristic diagram (3).

FIG. 9 is an operation characteristic diagram (4).

FIG. 10 is an explanatory view of a use state showing another embodiment.

FIG. 11 is a configuration explanatory view showing another embodiment.

FIG. 12 is an operation characteristic diagram (5).

FIG. 13 is a conceptual view showing the configuration of another embodiment (1).

FIG. 14 is an operating characteristic diagram (6).

FIG. 15 is a conceptual diagram showing the configuration of another embodiment (2).

FIG. 16 is an operation characteristic diagram (7).

FIG. 17 is an operation characteristic diagram (8).

FIG. 18 is a conceptual view showing the configuration of another embodiment (3).

FIG. 19 is an operation characteristic diagram (9).

[Explanation of symbols]

 d1 pitch 11 board 11b through-hole 12 terminal 15 cover material 15a engaging projection 20 coil 21 first conductor 22 second conductor 23 through hole

Claims (9)

[Claims] 1. A substrate, a first conductor arranged in parallel on a front surface of the substrate at a predetermined pitch, and a second conductor connecting one end of each of the first conductors to the other end on the back surface of the substrate.
And an antenna element for a portable communication terminal, wherein the first and second conductors form a coil via the substrate. 2. The antenna element for a portable communication terminal according to claim 1, wherein said first and second conductors are connected via a through hole formed in said substrate. 3. The apparatus according to claim 1, wherein the coil is divided and formed on a plurality of the stacked substrates.
Or an antenna element for a portable communication terminal according to claim 2. 4. The antenna element for a mobile communication terminal according to claim 1, wherein the coil is formed by forming a plurality of sets having different lengths at the same position in the same direction on the substrate. . 5. The antenna element for a mobile communication terminal according to claim 1, wherein the coil forms a plurality of sets having different lengths at different positions in the same direction on the substrate. . 6. The portable communication terminal according to claim 1, wherein a plurality of sets of the coils having the same length are formed at different positions in a direction perpendicular to each other on the substrate. Antenna element. 7. The antenna element for a portable communication terminal according to claim 1, wherein said substrate is protected by a cover material. 8. The antenna element for a portable communication terminal according to claim 7, wherein a through hole is provided in said substrate. 9. The antenna element for a portable communication terminal according to claim 7, wherein an engaging projection for fixing is projected from said cover member.