JPH1127041A - Antenna for portable communication terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sensitivity and distance of communication by placing a secondary element at a position near a primary element and securing the resonance of coils of both primary and secondary elements with the prescribed frequency and improving the overall directivity. SOLUTION: A primary element 10 is combined with a secondary element 20 which is placed near the element 10. The element 10 includes a coil 12 of a prescribed pitch d1a which is formed on a longitudinal substrate 11 of thickness t1 via the conductors 12a and 12b formed on both sides of the substrate 11 and a through-hole 12c. The element 20 includes a coil 22 which is formed on a longitudinal substrate 21 of thickness t2 by connecting together the conductors 22a and 22b formed on both sides of the substrate 21 at a prescribed pitch d2a via a through-hole 22c. However, the pitch d2a of the coil 22 is set equal to the pitch d1a of the coil 12, and the coil 22 has the same number of turns as the coil 12 and also has the same shape as the coil 12 with the thickness t2 of the substrate 22 set equal to the thickness t1 of the substrate 11 respectively.

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 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 projecting 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. In addition, since the helical antenna is composed of an antenna element composed of an air-core coil, the communication sensitivity tends to change depending on the use posture, the direction of the base station, and the like, and it is difficult to maintain a good communication state, and the communication distance is short The problem of not being big was inevitable.

[0004] In view of the above-mentioned problems in the prior art, an object of the present invention is to minimize the external dimensions by combining the main element and the sub-element, improve the communication sensitivity and the communication distance, and improve the communication state. An object of the present invention is to provide an antenna for a portable communication terminal that can be maintained.

[0005]

According to an aspect of the present invention, there is provided a combination of a main element and a sub-element forming a coil having a predetermined pitch via a vertically long substrate. The gist is to dispose it near the element.

The main element and the sub-element can be arranged such that their respective central axes are included in two planes orthogonal to each other.

However, the main element and the sub element are
Each substrate can be arranged so as to be included in two planes orthogonal to each other or on the same plane.

[0008]

According to the structure of the present invention, the main element and the sub-element are formed with coils of a predetermined pitch via a vertically long substrate, and can resonate each coil at a predetermined use frequency. However, it is assumed that the main element is used as a monopole antenna in combination with a sufficiently large ground plane, and the sub-element is not electrically connected to the main element. Also, the coils of the main element and the sub-element are each formed to have a length electrically equivalent to an odd multiple of λ / 4 with respect to the wavelength λ of the operating frequency.

When the main element and the sub-element are arranged such that their respective central axes are included in two planes orthogonal to each other, the coil of the sub-element is vertically polarized when the coil of the main element resonates with horizontal polarization. When the coil of the main element resonates with the vertical polarization, it can resonate with the horizontal polarization, and as a whole, can transmit and receive both the horizontal polarization and the vertical polarization. A polarization combining array antenna can be configured.

When the main element and the sub-element are arranged so that each substrate is included in two planes orthogonal to each other, the main element and the sub-element have a directional characteristic of 3
It becomes broad in dimension, and good omnidirectionality can be easily realized.

When the main element and the sub-element are arranged so that the respective substrates are included in the same plane, the average gain in the directional characteristics increases, and high communication sensitivity can be realized as a whole.

[0012]

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

An antenna for a portable communication terminal is composed of a main element 10 and a sub-element 20 arranged near the main element 10 (FIGS. 1 and 2).

The main element 10 is formed by a conductor 12 formed on the front and back surfaces of a vertically long substrate 11 having a thickness t 1.
.., 12b, 12b.
The coils 12 having a predetermined pitch d1a are formed via the coils c, 12c,. The substrate 11 is a double-sided printed circuit board having good high frequency characteristics such as ceramics, fluororesin or epoxy resin, and a terminal 11a for cable connection having a through hole 11a1 is formed on one end of the substrate 11 at one end. ing.

Are arranged in parallel on the surface of the substrate 11 at every pitch d1a, and the conductors 12b, 12b.
One end of each conductor 12a is sequentially connected to the other end via c and 12c. Therefore, the conductors 12a, 12a.
., 12b... have a length d1 as a whole through the substrate 11.
b, a coil 12 having a width d1c is formed. However, the first conductor 12a on the proximal end side of the coil 12 is connected to the terminal portion 11a via the connection wire 12d.

The sub-element 20 is formed on a vertically long substrate 21 having a thickness t2 by a conductor 2 formed at predetermined pitches d2a on the front and back surfaces of the substrate 21 through through holes 22c, 22c.
2a, 22a..., 22b, 22b.
2 are formed. However, the coil 22 has a pitch d
2a = d1a, length d2b = d1b, width d2c = d1c, the number of turns is the same as that of the coil 12, and the thickness t2 of the substrate 22 =
It is formed in the same shape as the coil 12 as t1.

The main element 10 and the sub-element 20 are
For example, it is attached to the case B of the mobile phone (FIG. 1,
(Fig. 3). However, the main element 10 is protected via a vertically long tapered dome-shaped cover member 13. The cover member 13 is integrally formed in a predetermined shape with the terminal portion 11a exposed in the case B. The main element 10 includes the substrate 1
1 is parallel to the front surface of the case B, and is fixed by protruding from the front end of the case B.
Is parallel to the front end surface of the case B and is incorporated in the front end of the case B. That is, the sub-element 20 is arranged near the main element 10, and the coils 12, 22 of the main element 10 and the sub-element 20 are arranged such that their respective central axes C1, C2 are included in two planes orthogonal to each other. Are located. Furthermore, the substrates 11 and 21 of the main element 10 and the sub-element 20 are
It is arranged to be included in the plane.

In case B, a receiver B1, a display B2,
Various operation keys including the numeric keys B3, B3,...
4 etc. are incorporated. The main element 10
Is connected to a communication unit (not shown) in the case B via a core wire of a coaxial cable (not shown) connected to the terminal unit 11a. I have.

The antenna of FIG. 1 has a thickness t1 = t2 = 0.
Pitch d1a = d2a = 0.5 mm, length d1b = d2b = 22 mm, width d for 5 mm epoxy resin-based substrates 11 and 21.
When the coils 12 and 22 of 1c = d2c = 3.1 mm are formed and operated as a monopole antenna together with the ground plane, the received radio waves Sh and Sv composed of horizontally polarized waves and vertically polarized waves are
Horizontal directional characteristics and vertical directional characteristics as shown by solid lines in FIGS. 4 to 6 were obtained. However, in these figures, the alternate long and short dash line is the comparison characteristic when only the main element 10 is used, and the attached schematic diagram shows the 0 ° where the received radio waves Sh and Sv arrive.
The direction is illustrated. In the radial direction, the reception sensitivity dB
(DBd). That is, the main element 10 has the sub-element 20 resonating with the received radio waves Sh and Sv and operates as a director element or a reflector element. In addition, the directional characteristics are broadly improved, and good operation characteristics can be realized.

The antenna shown in FIG.
Compared to the case of only 0, the reception limit position of the communication wave S from the oscillation source P is expanded by the distance L and the height H (FIG. 7). However, in FIG. 7A, when there is no obstacle in the middle on a flat ground, the distance L = 1 when only the main element 10 is used.
The reception limit position is enlarged by 5.5 m, and FIG. 4B shows that when the slope F is an obstacle, the reception is performed by the distance L = 4 m and the height H = 0.5 m compared to the case where only the main element 10 is used. This indicates that the limit position has expanded.

[0021]

[Other Embodiment] In the main element 10, the substrate 11 may be arranged in the thickness direction of the case B (FIG. 8A).
(B)). In addition, the sub-element 20 may arrange the substrate 21 in parallel with the front surface of the case B (FIG.
(C)). That is, the main element 10 and the sub-element 20 may be arranged such that the respective substrates 11 and 21 are included in two planes orthogonal to each other (FIG. 8A,
(B)) and may be arranged so as to be included in the same plane (FIG. (C)). However, in FIG. 8C, the sub-element 20 may be offset from the main element 10 in the thickness direction of the case B.

In the above description, the sub-element 20
May be protected over the entire surface via a suitable cover material, and may be attached to the front end surface of the case B from outside. Further, the sub-element 20 is entirely protected by the cover member 23 (FIG. 9).
It may be detachably connected to the cover material 13 for the main element 10 via a mounting opening 23a formed in the cover material 23.

The main element 10 and the sub element 2
0 is a plurality of substrates 11, 11,.
The coils 12 and 22 can be formed on 1, 21,... Separately (FIG. 10). However, FIG. 10 shows only the main element 10.

The coil 12 has a base side 12e corresponding to a half of the whole, formed on the intermediate substrate 11 (FIG. 10).
(A), (B)), front end side 12f corresponding to the other half
Are formed so as to overlap the upper and lower substrates 11, 11, and the base 12 e and the distal ends 12 f, 12 f
Are connected via a connection line 12g that passes through. In addition,
The substrates 11, 11... Can be integrally finished by closely contacting and layering (FIG. (C)). Each substrate 11
Is formed integrally with a terminal portion 11a having a through hole 11a1. Coil 1 via connecting wire 12d
The core wire 15a of the coaxial cable 15 is commonly connected to the terminal portions 11a, 11a,... Connected to one end of the second 2, and the shield jacket 15b of the coaxial cable 15 is connected to the base plate 14.

In the main element 10, a plurality of sets of coils 12, 12 having different lengths may be formed at the same position in the same direction on the substrate 11 (FIG. 11A). May be formed at different positions in the same direction (FIG. (B)), and a plurality of sets of coils 12, 12 having the same length may be formed at different positions at right angles to each other. Good (FIG. (C)). In addition, FIG.
In (C), each coil 12 is connected to a connecting wire 12.
d is drawn out to the terminal portion 11a. Further, the sub-element 20 can be configured in exactly the same manner.

[0026]

As described above, according to the present invention, by disposing the sub-element in the vicinity of the main element, the main element and the sub-element have their respective coils resonating at a predetermined operating frequency, and As the directional characteristics can be improved, the communication sensitivity and the communication distance can be improved, the communication state can be kept good, and the outer dimensions of each can be minimized. There is an excellent effect that it can be attached in a good style.

Further, since the sub element is not electrically connected to the main element, the VSWR of the main element
The effect on the characteristics is small and the overall adjustment is easy.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view of the overall configuration.

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

FIG. 3 is an illustration of a use state.

FIG. 4 is an operation characteristic diagram (1).

FIG. 5 is an operation characteristic diagram (2).

FIG. 6 is an operation characteristic diagram (3).

FIG. 7 is an explanatory diagram of operating characteristics.

FIG. 8 is a view (1) corresponding to FIG. 1 showing another embodiment.

FIG. 9 is a diagram (2) corresponding to FIG. 1, showing another embodiment.

FIG. 10 is a configuration explanatory view showing another embodiment (1).

FIG. 11 is a configuration explanatory view showing another embodiment (2).

[Explanation of symbols]

 d1a, d2a: Pitch C1, C2: Central axis 10: Main element 20: Subelement 11, 21, Substrate 12, 22: Coil

Claims (4)

[Claims] 1. A portable communication terminal comprising a combination of a main element and a sub-element forming a coil of a predetermined pitch via a vertically long substrate, wherein the sub-element is arranged near the main element. Antenna. 2. The antenna for a portable communication terminal according to claim 1, wherein the main element and the sub-element are arranged such that respective central axes are included in two planes orthogonal to each other. 3. The mobile communication terminal according to claim 1, wherein the main element and the sub-element are arranged such that each of the substrates is included in two planes orthogonal to each other. antenna. 4. The antenna for a portable communication terminal according to claim 1, wherein the main element and the sub-element are arranged such that the respective substrates are included in the same plane.