JPH0225282B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a portable radio device in which an inverted F-shaped antenna is attached to a housing housing a radio unit, a receiver, and a transmitter.

``Prior Art'' Conventionally, portable radio devices that use an inverted F-shaped antenna and can incorporate an antenna into the radio device body (casing) include those with the antenna element mounted on the top surface of the radio device casing; Or there was one on the back of the radio case. As shown in FIG. 6, the receiver 13 is attached to the upper part and the transmitter 14 is attached to the lower part of the front surface 12 of the radio housing 11, which has a substantially rectangular cylindrical shape. A radio unit is housed within the body 11. Top surface 15 of housing 11
An inverted F-shaped antenna 16 is attached to the antenna. That is, a plate-shaped antenna element 17 is arranged opposite to the top surface 15, and the plate-shaped antenna element 17 is connected to the housing 11 at a grounding part 18, and a power feeding part 19 is provided near the grounding part 18.

Alternatively, as shown in FIG.
An inverted F-shaped antenna 16 is attached to the top of the antenna. Inverted F-shaped antenna 1 in these portable radios
Measurement examples of the radiation directivity of No. 6 are shown in FIGS. 8 and 9, respectively. FIG. 8A shows the x-y plane directivity of the inverted F-shaped antenna 16 in the top installation structure of FIG.
Figure B is an example of measurement of x-z plane directivity, and Figure 9A
7B is an example of measurement of the x-y plane directivity of the inverted F-shaped antenna 16 in the rear installation structure shown in FIG. 7, and FIG. 9B is an example of measurement of the x-z plane directivity. The coordinate systems in FIGS. 8 and 9 are based on the coordinate systems shown in FIGS. 6 and 7, respectively.
In addition, in FIGS. 8 and 9, the solid line 22 represents the |E〓| component, and the broken line 23 represents the |E〓| component.
0dBd represents the maximum radiation level of a standard dipole antenna.

Because of this directivity, Figure 6,
The portable radio device with the conventional configuration shown in Fig. 7 is
When the housing 11 is used in a nearly upright position, x-
Since the directivity of the |E〓| component in the y plane corresponds to the vertical polarization sensitivity in the horizontal plane, it has good sensitivity in a mobile radio system using vertical polarization. However, when the receiver 13 is placed against the human ear, the transmitter 1
When making a call with the radio device 4 close to the mouth, the radio housing 11 is tilted significantly.
The directivity of the antenna has characteristics close to the x-z plane directivity, and the vertical polarization sensitivity in that case is the |E〓| component (dashed line) in the x-z plane in Figures 8B and 9B.
As is clear from this figure, the effective gain of the antenna is significantly degraded.
According to field experiments, when the radio is placed upright, the effective antenna gain is about -8 dB compared to a dipole antenna in a top-mounted structure, and about -5 dB compared to a dipole antenna in a rear-mounted structure; When attached to the head side of the human body, the antenna effective gain is about -11 dB compared to the dipole antenna with the top-mounted structure.
With the rear-mounted structure, the dipole antenna ratio was about -8 dB.

As a means to solve this drawback, it is conceivable to install an inverted F-shaped antenna 16 on the side surface 24 of the radio device housing 11 as shown in FIG. The upper part of the side surface 24 is further pulled in to form a stepped portion 25.
is provided, and a plate-shaped antenna element 17 is attached to the retracted portion. Inverted F-shaped antenna 1
The grounding portion 18 of No. 6 is arranged at the upper end of the side surface 24 of the casing, which is the antenna mounting surface. When a feeding current flows through the power feeding section 19, a considerable amount of current flows through the grounding section 18. Therefore, when the grounding section 18 is placed at the lower end of the plate antenna element 17, the side surface 2 of the housing
Since the antenna characteristics are significantly deteriorated due to capacitive coupling with the stepped portion 25 of the ground portion 18, it is desirable that the ground portion 18 be placed at the upper end of the side surface 24 of the housing.

According to the side installation structure shown in FIG. 10, the radiation directivity of the inverted F-shaped antenna 16 is as shown in FIG. 11. 11A and 11B are the x-y plane and x-z plane of the inverted F-shaped antenna 16 in the side-mounted structure, respectively.
In the measurement example of in-plane directivity, the solid line 22 is |E〓|
The broken line 23 represents the |E〓| component. Also
0dBd represents the maximum radiation level of a standard dipole antenna. Because of this directional characteristic, vertical polarization sensitivity when the radio device housing 11 is placed upright can be maintained at the same level as the rear installation structure shown in FIG. x-z in Figure 11B even when talking while tilting the phone.
|E〓|component directivity in surface directivity (dashed line 23)
It is considered that the sensitivity to vertically polarized waves is almost the same, so that the sensitivity to vertically polarized waves during a call can be made better than the conventional configurations shown in FIGS. 6 and 7. According to field experiments, when the radio housing 11 is placed upright, the antenna effective gain is about -4 dB compared to a dipole antenna, and when the radio housing 11 is tilted and attached to the human head, the antenna effective gain is inverted F. When the shaped antenna 16 is directed upward, the dipole antenna ratio is about -6 dB, and the inverted F-shaped antenna 16
When the antenna was directed downward, the dipole antenna ratio was about -7 dB. As explained above, the first
In the side installation structure shown in Figure 0, at least Figures 6 and 7
The effective gain during communication of the inverted F-shaped antenna can be improved compared to the structure shown in the figure. However, this side-mounted structure has the disadvantage that the effective gain varies depending on whether the antenna is installed upward or downward during a call.

"Means for Solving the Problem" According to the present invention, one inverted F-shaped antenna is fixed on each side of the radio device housing at a position almost adjacent to the receiver, and these two inverted F-shaped antennas The grounding part of the antenna is placed at the upper end of the antenna mounting surface of the housing, and the radio unit is connected to the power feeding part of these two inverted F-shaped antennas by switching with a high-frequency signal switcher, and a detector detects the tilt of the housing. The detection signal controls switching of the high frequency signal switch.

Embodiment FIG. 1 shows an example of a portable wireless device according to the present invention, and parts corresponding to those in FIGS. 6, 7, and 10 are given the same reference numerals. In this embodiment, the housing 11
An inverted F-shaped antenna 1 is installed on the top of both sides 24, 24' of the
6 and 16' are respectively attached. The mounting of the inverted F-shaped antenna 16 is the same as the configuration shown in FIG. 10, and the inverted F-shaped antenna 16' is also the same, so the same numbers are indicated with a dash "'". Housing 11
The radio device section 27 in
It is switched and connected to each feeder line 30, 30' of 9'.
A detector 2 inside the housing 11 detects the inclination of the housing 11.
9 is provided, and the switching of the high frequency signal switch 28 is controlled by the detection signal of this detector 29.

The detector 29 for detecting the inclination of the housing can be realized using a non-contact displacement sensor using a magnetoresistive element, for example, in the longitudinal direction of the wireless device housing 11 (in the Z direction in FIG. ) is tilted at an inclination angle θ with respect to the vertical axis as shown in Figure 2, that is, the direction perpendicular to the two planes on which the inverted F-shaped antenna is provided (the Y direction in Figure 6) is at an angle θ with respect to the horizontal plane.
When the tilt angle is θ, the detector 29 outputs a detection signal as shown in FIG. 3 with respect to the tilt angle θ. The polarity of θ is Y
Corresponds to whether the direction is tilted upward or downward with respect to the horizontal plane. As shown in FIG. 2, the movable element 31 in the detector 29 moves to
Move to the opposite end of 9. In other words, this movable element 3
1 can be imagined as a small iron ball, detector 29
It always moves downwards depending on the tilt of the portable radio. In FIG. 3, a solid line 32 is an example in which the detection signal does not have hysteresis with respect to a change in the inclination angle θ, and a dashed-dotted line 33 is an example in which the detection signal has hysteresis.

The high-frequency signal switch 28 is switched and controlled by the detection signal of the detector 29, so that the feed line of the inverted F-shaped antenna is always directed upward, regardless of the direction of inclination of the radio housing 11, as shown in FIG. is the radio section 2
7 and be electrically connected.

The effect of this configuration is that of the two inverted F-shaped antennas 16 and 16', the antenna with the higher effective gain is connected to the radio section 27, which reduces the antenna gain during a call. Fluctuations can be eliminated, and an antenna with good sensitivity can always be used.

FIG. 5 is a rear view of another embodiment of the present invention, which has a structure in which no step is provided in the inverted F-shaped antenna installation portion of the side surfaces 24 and 24' of the housing, and the same effect and effect as in the case where there is a step is obtained. is obtained.

"Effects of the Invention" As explained above, according to the present invention, the antenna effective gain during a call of a portable radio device with a built-in antenna in the radio device casing is - compared to a dipole antenna.
This is approximately 6 dB, making it possible to increase the effective antenna gain by approximately 2 dB compared to the conventional configuration. Therefore, the present invention greatly contributes to improving the call quality when using a portable radio, expanding the service area, etc., and its effects are extremely high in practical terms. In addition, since the inverted F-shaped antenna has wideband characteristics, it is convenient to apply to mobile communication systems using multiple channels.
This is extremely effective in realizing a portable wireless device with excellent portability.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing an embodiment of the present invention, Fig. 2 is a conceptual diagram showing the relationship between the inclination of the housing and the operation of the detector 29, Fig. 3 is a diagram of the output characteristics of the detector, and Fig. 4 5 is a rear view showing another embodiment of the invention, and FIGS. 6 and 7 are perspective views showing a portable wireless device using a conventional inverted F-shaped antenna. Figure 8 is a diagram showing an example of measuring antenna directivity in the conventional configuration of Figure 6, Figure 9 is a diagram showing an example of measuring antenna directivity in the conventional configuration of Figure 7, and Figure 10 is an inverted F FIG. 11 is a perspective view showing an example of a portable radio device having a shaped antenna attached to the side surface of the housing. 11: Housing, 13: Receiver, 14: Transmitter, 1
6, 16': Inverted F-shaped antenna, 17, 17': Plate antenna element, 18, 18': Power feeding section, 19, 1
9': Grounding part, 22: |E〓| Directivity of component, 2
3: |E〓|directivity of component, 24, 24': side of housing, 27: radio unit, 28: high frequency signal switch,
29: Detector for detecting the inclination of the housing, 30,3
0': Power supply line.

Claims (1)

[Scope of Claims] 1. A casing having at least first and second opposing side surfaces and accommodating a radio unit, a receiver, and a transmitter; The third
In the portable radio device in which the transmitter and the receiver are fixed to the surface of the receiver, a first inverted F-shaped antenna and a second inverted F-shaped antenna are arranged on the first side surface and the second side surface, respectively. The grounding parts of the first and second inverted F-shaped antennas are respectively arranged at the upper end of the antenna mounting surface of the housing, and the feed lines of these two inverted F-shaped antennas are connected to high-frequency signals. Switchable and connected to the radio unit via a switch, detects whether the direction orthogonal to the first side surface and the second side surface of the housing is upward or downward with respect to the horizontal plane, and changes the direction. 1. A switching antenna type portable wireless device, characterized in that a detector that outputs a detection signal from time to time is housed in the housing, and switching of the high frequency signal switch is controlled by the detection signal from the detector.