JP3042316B2 - Antenna device and portable wireless device having the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small portable radio, and more particularly to an antenna device for improving antenna characteristics.

[0002]

2. Description of the Related Art As an antenna device using two substantially parallel conductor plates among the antenna devices of a portable radio device, as described in Japanese Patent Application Laid-Open No. 1-241927, there are two antenna devices. An example in which a conductor plate is placed with a gap, a conductor plate is short-circuited at a short-circuit portion, and a loop antenna is configured by loading a capacitive element at a feed point position as shown in the circuit diagram of the same publication, Japanese Patent Application Laid-Open No. 6-244618 discloses an example of a loop antenna in which a short-circuit conductor for short-circuiting a feeding point and two rectangular conductor plates is arranged near a diagonal position.

[0003]

However, the antenna device of such a conventional portable radio device using a loop antenna is used for a small portable radio device, and the antenna size is limited to a small size. However, it was difficult to obtain a necessary and sufficient antenna gain, and it was difficult to maintain satisfactory communication quality of a wireless device.

Accordingly, the present invention solves such a problem. In an antenna device of a portable radio, a structure which can obtain a larger antenna gain by using a slot antenna mode with a simple structure than in the past. It is intended to provide. It is another object of the present invention to provide a configuration of a portable wireless device that can effectively use a space in a wireless device main body without deteriorating antenna characteristics and can be downsized.

In order to achieve the above object, a portable wireless device of the present invention according to the present invention is characterized in that two rectangular conductor plates placed substantially in parallel with a gap therebetween and the two conductors are provided. A portable wireless device circuit portion configured between the plates, a short-circuit plate in which the conductor plates are short-circuited at the conductor plate ends, and the conductor plate end portion at a position diagonal to the position of the short-circuit plate on the conductor plate A portable wireless device having an antenna device having a capacitive element loaded on the two conductive plates, a feed point disposed on the two conductor plates at a position different from a position where the capacitive element is loaded, and the two conductors A notch portion formed in each of the plates, and the notch portion is formed at a position on the conductor plate facing the portable wireless device circuit portion, with a gap in the portable wireless device circuit portion. It is characterized by the following.

According to a second aspect of the present invention, in the first aspect, the opening is located near a local oscillator or a DC-DC converter in the portable wireless device circuit.

[0007]

[0008]

According to the structure of the portable wireless device of the present invention, it is considered that a loop antenna and a slot antenna are combined in order to improve the antenna characteristics. It is assumed that antenna gain can be obtained. Further, the influence of the radio circuit on the antenna can be reduced.

The principle will be described below. In an antenna device having a conventional configuration, a loop antenna functions by using two conductor plates and a short-circuit portion. In this antenna device,
Although a capacitive element is loaded for tuning to a desired frequency, the capacitive element is connected to a feed point of the antenna by a feed line and can be said to be electrically located at the same position.

On the other hand, in the antenna device of the present invention, the position of the feeding point of the antenna is shifted from the position where the capacitive element is loaded on the conductor plate, and both positions are separated. This makes it possible for a slot formed around the side of the antenna device sandwiched between the two conductor plates to function as a slot antenna. As a result, it is considered that both the loop antenna mode and the slot antenna mode are added, so that a larger antenna gain can be obtained than in the case where only the loop antenna is used.

FIG. 6 shows an example of the antenna radiation directivity pattern measurement of the conventional example and the present invention. The vertical polarization component on the XY plane is shown, and is normalized by the maximum antenna gain. The solid line portion 110 is the measurement result of the present invention, and the dotted line portion 111 is the measurement result of the conventional example, and the conditions such as the dimensions and frequency of the antenna are the same. The X-axis direction in which the capacitive element is loaded is the maximum radiation direction, but the antenna gain of the present invention is larger than that of the conventional example, and the radiation pattern is generally round. Thus, it can be seen that the antenna characteristics are improved by combining the slot antenna with the conventional loop antenna.

The capacitive element loaded between the conductor plates has the purpose of tuning the antenna to a desired frequency by adjusting the capacitance value even in the slot antenna, and the loading position depends on the distribution of the current flowing through the conductor plate. Because the balance can be taken, the opposite side of the short-circuit plate improves the antenna characteristics most,
desirable.

Further, in the present invention utilizing the above-described principle, an attempt is made to obtain a larger antenna gain by arranging the capacitive element and the short-circuiting plate. FIG. 7A is a plan view of the antenna device, and FIG.
(B) is a side view thereof. Two substantially parallel conductor plates 112a and 112b, a short-circuit plate 113, and a capacitive element 1
14. The slot antenna is a magnetic field detection type antenna, and the magnetic field component 115 at the time of vertical polarization is in a horizontal direction (Y-axis direction) as shown in the figure. Due to this magnetic field component, currents in the same direction flow in the conductor plates 112a and 112b in the slot antenna mode and the loop antenna mode, and the two are added to obtain a large antenna gain.

FIG. 8 (a) is a plan view of a further improved antenna device of the present invention, and FIG. 8 (b) is a side view of the antenna device, which has the same configuration as that of FIG. Is attached. In FIG. 8, the short-circuit plate 113 and the capacitor 1
14 are arranged near the diagonal positions of the quadrangular conductor plates 112a and 112b, the substantial opening area 116 (hatched portion) of the side loop portion can be ensured as much as possible. Since the antenna gain increases as the aperture area of the loop antenna increases, the characteristics of the loop antenna can be improved, and a larger antenna gain can be obtained despite the same antenna dimensions. The effect of the optimum configuration of the antenna device as shown in FIG. 8 is that the antenna gain is improved by a maximum of about 3 dB as compared with the example of FIG.

[0015]

【Example】

(Embodiment 1) An antenna device according to the present invention and an embodiment for a portable radio equipped with the antenna device will be described in detail with reference to the drawings. FIG.
1 is a schematic perspective view of a portable wireless device according to an embodiment of the present invention. The two conductor plates 1a and 1b are placed substantially in parallel with a gap 2 therebetween. The material of the conductor plates 1a and 1b is copper, stainless steel, or the like. If copper is used, a relatively large antenna gain can be obtained because the electric resistance is small, and if it is made of stainless steel, it has excellent rust resistance and high durability. There are features. If there is no electrical influence, the outside of the conductor plates 1a and 1b and the outside of the radio device circuit section 5 may be covered with a plastic member or the like in order to improve the appearance. In this figure, the conductor plate 1a and the conductor plate 1b are drawn apart for the sake of explanation, but they are actually connected at the ends by the short-circuit plate 3.
The short-circuit plate 3 may not be formed integrally with the conductor plates 1a and 1b, but may be formed by means such as screwing as long as the conductor plates 1a and 1b can be electrically conducted. In this antenna device, a slot portion is formed around the side surfaces of the conductor plates 1a and 1b in such a configuration.

A capacitive element 4 mounted on the ends of the conductor plates 1a and 1b and on the opposite side of the short-circuit plate 3 is for tuning to a desired frequency, and is a fixed capacitor or a variable capacitor for fine adjustment. A capacitor or the like may be used. Also, a varactor diode may be used to cope with electronic tuning. The wireless device circuit unit 5 includes conductor plates 1a and 1b via power supply lines 7a and 7b.
And 8a and 8b, respectively.
When the feeding points 8a and 8b are the same as or very close to the loading position of the capacitive element 4, the present antenna device does not function as a slot antenna but only functions as a loop antenna, so that the antenna gain is reduced. Therefore, by properly shifting the positions of the feeding points 8a and 8b from the loading position of the capacitive element 4 on the conductor plates 1a and 1b, for example, as in this example, the present antenna device can reliably function as a slot antenna. Can be. In addition, since the power supply impedance of the conductor plates 1a and 1b also changes according to the power supply point position, the power supply impedance can be arbitrarily adjusted so that impedance matching with the wireless device circuit unit 5 can be easily achieved.

The radio circuit section 5 has a display means 6 such as a liquid crystal panel for displaying information of the portable radio, and is arranged outside the conductor plates 1a and 1b and parallel to the two conductor plates. Since there is no conductive material blocking between the conductor plates 1a and 1b, the antenna is in an ideal state and a large antenna gain can be obtained.

In the present invention, the slot antenna mode and the loop antenna mode are used, but both are magnetic field detection type antennas. Since the electromagnetic field distribution near the human body tends to have a strong magnetic field component and a small electric field component, when the portable wireless device of the present invention is worn on a human body or clothes in a portable state, the antenna characteristics are further improved as compared to a single unit. This has the effect of improving the sensitivity of the wireless device.

(Embodiment 2) FIG. 2 is a schematic perspective view of a portable radio device according to an embodiment of the present invention. A short-circuiting plate 10 connecting two rectangular conductor plates 9a and 9b, and a tuning capacitive element 1 mounted between the conductor plates 9a and 9b on the opposite side of the short-circuiting plate.
Reference numeral 1 is arranged near the diagonal position of the conductor plates 9a and 9b. With such a position arrangement of the short-circuit plate 10 and the capacitive element 11, a substantial opening area of the side loop portion can be secured as much as possible, and the characteristics as the loop antenna can be improved, and the antenna dimensions do not change. Nevertheless, the maximum antenna gain can be obtained. Also,
If there is no electrical influence, the outside of the conductor plates 9a and 9b and the outside of the radio device circuit section 12 may be covered with a plastic member or the like to improve the appearance.

The radio circuit section 12 includes power supply lines 14a, 14
b, they are connected at the feeding points of the conductor plates 9a, 9b and 15a, 15b, respectively. Also in this example, the feeding points 15a and 15b on the two conductor plates 9a and 9b are configured to be shifted from the position where the capacitive element 11 is loaded. The wireless device circuit unit 12 includes a display unit 13 such as a liquid crystal panel for displaying information on the portable wireless device.
Outside of the conductor 9b, the conductors are arranged parallel to the two conductor plates, and there is no conductor blocking between the conductor plates 9a, 9b, so that a larger antenna gain can be secured.

(Embodiment 3) FIG. 3 is a schematic perspective view of a portable wireless device according to an embodiment of the present invention. Two conductor plates 17a,
17b are placed substantially parallel with a gap. In this figure, the conductor plate 17a and the conductor plate 17b are drawn apart for the sake of explanation, but they are actually connected at the ends by short-circuit plates 18. If there is no electrical influence, the outside of the conductor plates 17a and 17b may be covered with a plastic member or the like to improve the appearance. Capacitors 19 loaded at the ends of the conductor plates 17a and 17b and on the opposite side of the short-circuit plate 18 are for tuning to a desired frequency, and are ceramic capacitors or the like.

The radio device circuit section 20 includes power supply lines 22a, 22
are connected at the power supply points of the conductor plates 17a, 17b and 23a, 23b via the b. Two conductor plates 17
a and 17b are connected to the capacitive element 19
Is shifted from the position at which it is loaded.

The radio device circuit section 20 has a display means 21 such as a liquid crystal panel, and is formed between the conductor plates 17a and 17b. In such a configuration, the space in the portable wireless device including the antenna device can be effectively used, and the size of the entire device can be reduced. A cutout (hereinafter referred to as a window) 24 is provided at a position on the conductor plates 17a and 17b which overlaps the radio circuit.
a and 24b are arranged. In the upper conductor plate 17a, the display contents of the display means 21 can be confirmed from the outside, and in the lower conductor plate 17b, the battery (not shown) of the portable wireless device is replaced. There is a purpose to make it easier. In the case of a structure in which the battery is replaced from the side, the window 24b may not be provided and only the window 24a may be provided. In addition, this window 24
a, 24b, the conductor plates 17a, 17b
And the radio device circuit section 20 can be made large,
There is also a role of reducing the amount of noise generated by the radio device circuit 20 to enter the antenna and obtaining good antenna characteristics. So this window is 24a, 24b
Is more effective when it is provided near a local oscillator, a DC-DC converter, or the like, which tends to generate particularly large noise even in a radio circuit.

(Embodiment 4) FIG. 4 is a schematic perspective view of a portable wireless device according to an embodiment of the present invention. The capacitive element 27 loaded between the two substantially parallel rectangular conductor plates 25a and 25b includes a short-circuit plate 26 and the square conductor plates 25a and 25b.
5b are arranged near the diagonal position. By such a position arrangement of the short-circuiting plate 26 and the capacitive element 27, the substantial opening area of the side loop portion can be ensured as much as possible, and the characteristics as the loop antenna are improved, and the antenna dimensions do not change. Nevertheless, a larger antenna gain can be obtained. Power supply line 30a,
30b is connected to each of the conductor plates 25a, 25b and 31a, 31b at a feeding point. Also in this example, the positions of the feeding points 31a and 31b are shifted from the position where the capacitive element 27 is loaded. If there is no electrical influence, the outside of the conductor plates 25a and 25b may be covered with a plastic member or the like to improve the appearance.

A radio circuit section 28 having a display means 29 such as a liquid crystal panel is placed between the conductor plates 25a and 25b. In such a configuration, the space in the portable wireless device including the antenna device can be effectively used, and the size of the entire device can be reduced.

Cutouts (hereinafter referred to as windows) 32a and 32b are formed at the center of the conductor plates 25a and 25b.
The upper conductor plate 25a has a purpose of allowing the display contents of the display means 29 to be externally confirmed, and the lower conductor plate 25b has a purpose of facilitating replacement of a battery (not shown) of the portable wireless device. . In the case of a structure in which the battery is replaced from the side, the window 24b may not be provided and only the window 24a may be provided. Further, by providing the windows 32a and 32b, the distance between the conductor plates 25a and 25b and the radio circuit section 28 can be increased, and the amount of noise generated by the radio circuit section 28 entering the antenna can be reduced. There is also a role that good antenna characteristics can be obtained.

FIG. 5 is a block diagram showing one embodiment of the configuration of the portable wireless device of the present invention. In the figure, an antenna device 100 includes a receiving circuit 101 including an antenna matching circuit.
Is connected to The signal from the VCO 102 is applied to the receiving circuit unit 101 via the frequency synthesizer 103. The signal amplified and filtered by the receiving circuit 101 is demodulated by the demodulation circuit 104, decoded and processed by the signal processing circuit 105, and enters the CPU 106. CPU10
6 is a display means 107 such as a liquid crystal panel,
The sounding means 108 such as a piezoelectric element or an electromagnetic buzzer is driven. In some cases, an audio signal is transmitted through a speaker. Further, input means 109 such as a switch is connected to the CPU 106. Power is supplied to these components from a built-in battery.

In this embodiment, an example is shown in which the portable radio has a receiving function. However, the effects of the antenna apparatus of the present invention and the portable radio equipped with the same do not change even if the portable radio has only the transmission / reception function. .

[0029]

As described above, in the antenna device according to the present invention, the position of the feeding point on the two conductor plates is made different from the position where the capacitive element for tuning is loaded.
This antenna device can reliably function as a slot antenna, and an antenna gain larger than that of a conventional loop antenna can be obtained. Also, by arbitrarily moving the position of the feeding point so that the impedance matching between the wireless device circuit unit and the antenna unit can be easily achieved, the feeding impedance of the conductor plate at the feeding point can be arbitrarily adjusted.

Further, by disposing the short-circuiting plate and the capacitive element near the diagonal position of the rectangular conductor plate, a larger antenna gain can be obtained by maximizing the loop antenna mode without increasing the size of the portable radio. Obtainable. Both the slot antenna and the loop antenna are magnetic field detection type antennas, and the electromagnetic field distribution near the human body has a large magnetic field component, so the sensitivity of the wireless device is improved, making it suitable as an antenna device for a portable wireless device used near the human body. I have.

Further, according to the portable wireless device of the present invention, 2
The circuit portion of the radio device is formed between the conductor plates, and the cutout (window) is provided in the conductor plate, so that the influence of noise and the like from the radio device circuit can be reduced. It is possible to configure a small-sized portable wireless device that makes effective use of the internal space.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing Embodiment 1 of a portable wireless device including an antenna device of the present invention.

FIG. 2 is a schematic perspective view showing Embodiment 2 of a portable wireless device including the antenna device of the present invention.

FIG. 3 is a schematic perspective view showing Embodiment 3 of a portable wireless device including the antenna device of the present invention.

FIG. 4 is a schematic perspective view showing Embodiment 4 of a portable wireless device including the antenna device of the present invention.

FIG. 5 is a block diagram showing an embodiment of the configuration of the portable wireless device of the present invention.

FIG. 6 is a graph showing the antenna radiation directivity of the antenna device of the present invention and the conventional example.

FIGS. 7A and 7B are diagrams showing antenna characteristics depending on the arrangement position of a capacitive element, wherein FIG. 7A is a plan view of the antenna device, and FIG. 7B is a side view thereof.

FIG. 8 is a diagram for explaining the operation of the present invention,
(A) is a top view of the antenna device by this invention,
(B) is a side view thereof.

[Explanation of symbols]

 2 gap 1a, 9a, 17a, 25a, 111a conductor plate 1b, 9b, 17b, 25b, 111b conductor plate 3, 10, 18, 26, 112 short-circuit plate 4, 11, 19, 27, 113 capacitance element 5, 12, 20, 28 wireless device circuit section 7a, 14a, 22a, 30a power supply line 7b, 14b, 22a, 30b power supply line 114 magnetic field component 115 loop opening 6, 13, 21, 31 display means 8a, 15a, 23a, 31a power supply Points 8b, 15b, 23b, 31b Feeding points 24a, 32a Cutouts (windows) 24b, 24b Cutouts (windows) 100 Antenna device 101 Receiving circuit 102 VCO 103 Frequency synthesizer 104 Demodulation circuit 105 Signal processing circuit 106 CPU 107 Display means 108 Sounding means 109 Input means 110 Antenna directivity of the present invention Constant results 111 antenna directivity measurement result of the conventional example

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01Q 1/24 H01Q 13/10

Claims (2)

(57) [Claims] An electronic device comprising: two rectangular conductor plates placed substantially in parallel with a gap therebetween; a portable radio device circuit portion formed between the two conductor plates; and an end portion of the conductor plate. In a portable wireless device having an antenna device having a short-circuit plate in which the conductor plates are short-circuited, and a capacitive element loaded at an end of the conductor plate at a position diagonal to the position of the short-circuit plate on the conductor plate, A feeding point disposed on a position different from the position where the capacitive element is loaded on the two conductor plates, a notch formed in each of the two conductor plates, and the notch; A portable wireless device formed at a position on the conductive plate facing the portable wireless device circuit portion with a gap in the portable wireless device circuit portion. 2. The portable wireless device according to claim 1, wherein the opening is located near a local oscillator or a DC-DC converter in the portable wireless device circuit unit.