JPS6048626A - Portable radio equipment - Google Patents

Abstract

PURPOSE:To improve the reliability by providing a concaved part to a case so as to form the diversity antenna constitution where the height of a projected antenna is decreased in a radio equipment having the case containing a radio equipment section and an antenna. CONSTITUTION:The concaved part 8 is provided to the case 7 and plural inverse-F antennas having the construction folded with plate conductor elements 9, 10 is fitted to the concaved part. The radiation directivity of the 1st inverse- F form antennas 9, 11 and 13 and the 2nd inverse-F form antennas 10, 12 and 14 is different largely and then, the incoming wave received by each antenna element in a multiplex propagating path becomes a different wave. That is, even if the antenna distance is decreased, since the directivity of each antenna element is different largely, the correlation of the received wave extracted from each antenna element is decreased and the practically sufficient diversity effect is given. Further, the case part exists between a human body and the antanna in mounting the radio equipment by installing the antenna element at the back side of the case of the radio equipment opposite to a handset, thereby offering an advantage decreasing the effect of the human body.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a portable mobile device equipped with a diversity antenna that can be built into a radio device body.

(Background technology) What are the diversity antennas for conventional portable radios?
An antenna constructed of two 1/4 wavelength whip antennas l mounted on a housing as shown in the fSf diagram was used. In FIG. 1, 2 is a housing of the radio, 3 is a receiver, and 4 is a transmitter.

However, since the antenna element of the above-mentioned antenna protrudes from the top surface of the housing, it is easily damaged during operation, which is a major factor in lowering the reliability of the radio device.

Furthermore, the correlation coefficient between the output signals of two antenna elements, which represents the performance as a diversity antenna, depends on the antenna spacing d. In order to configure a practical diversity antenna, the antenna element spacing d should be d≧0.1・λ0
(80 is the wavelength) had to be satisfied. In particular, if a broadband antenna is required, the antenna spacing will be wider than the above condition. For example, in the 800 MHz band car telephone system, the fractional band is required to be about 8%, and in this case, d>0.225 people. It must be. That is,
Since it is a λop33 arm, d must be greater than 7.5 cm, which has the disadvantage of placing a large constraint on the miniaturization of portable devices.

(Objective of the Invention) In order to eliminate the above-mentioned drawbacks, the present invention provides a housing with a recess, and configures a plurality of inverted F-shaped antennas with radiating elements bent in the four parts, so that the antenna protrudes from the housing. The present invention is characterized by having a dipole antenna ratio configuration with a reduced height, and its purpose is to provide a highly reliable portable diversity radio.

(Structure and operation of the invention) Figure 1 shows an embodiment of the present invention, in which 5 is a transmitter, 6 is a receiver, 7 is a housing, 8 is a recessed portion, and 9.10 is a plate shaped like an L-shaped bent portion. The element, 11.12 is a ground conductor, and 13.degree. and 14 is a power feeding section. FIG. 2 shows an example in which there are two antenna elements. In Figure 2, the first inverted F-shaped antenna is configured at 9.11.13°, and the second inverted F-shaped antenna is configured at 10.12.14 degrees, and each is placed on the opposite side with the housing in between. The configuration is such that antenna elements are arranged. Because of this structure, the radiation directivities of the first and second inverted F-shaped antennas are significantly different, and therefore the arriving waves received by each antenna element within the multiplex transmission path are different waves.

In other words, even if the antenna spacing is made smaller than in the conventional configuration, the directivity of each antenna element is greatly different, so the correlation between the received waves extracted from each antenna element can be reduced, making it possible to achieve a practically sufficient diversity effect. You can have it. In addition, as shown in Figure 2, by installing the antenna element on the back side of the radio casing facing the handset, the casing part is present between the human body and the antenna when worn on the human body (during a call). This has the advantage of reducing the impact on the human body.

According to field experiments, the gain of each inverted F antenna of the present invention when worn on the human body is approximately -8 compared to a dipole antenna.
dB, which is similar to the gain of a conventional inverted-F antenna. Further, the correlation coefficient of the received voltages in each inverted F-shaped antenna element in the present invention is 0.6 or less, which is a sufficient correlation for practical use. ·I understand.

Further, according to the present invention, since the structure is such that the plate-like element is bent, the shape of the recessed portion of the housing can be determined arbitrarily, and there is an advantage that the interior of the housing can be effectively utilized.

FIGS. 3 and 4 show another embodiment of the present invention in which the shape of the four parts and the installation direction of the L cedar plate element are changed, and the diversity effect is the same as the structure shown in FIG. 2. Further, the plate-like element may have a shape other than the L-shape, an example of which is shown in FIG. (a
) is an example where the bending angle is larger than 80°, (b) is an example where the bending part is rounded, and (c) is an example where the bending angle is 90°.
Here is an example that is larger and rounder than °.

(Effects of the Invention) As explained above, according to the present invention, the antenna element can be configured without protruding from the radio device, and the antenna gain when worn on the human body does not deteriorate, and the antenna element does not depend on the antenna spacing. First, because the antenna configuration has a large diversity effect, it is possible to realize a highly reliable small portable diversity radio device, and it is especially effective in realizing small portable radio devices such as mobile phones for mobile phone systems. It is.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a portable radio device using a conventional whip antenna, Fig. 2 is a configuration diagram showing an embodiment of the present invention, and Fig. 3 is a schematic diagram of a portable radio device using a conventional whip antenna.
4 and 4 are block diagrams showing other embodiments of the present invention, respectively, and FIG. 5 is an example in which the shape of the plate element is changed. 1... Whip antenna, 2, 7... Housing 3.6
... Transmitter, 4, 5... Receiver 8... Housing recess, 9, 10... Plate elements 11, 12... Grounding part conductor, 13.14... Power feeding part patent Applicant: Nippon Telegraph and Telephone Public Corporation Patent attorney: Megumi Yamaki

Claims (1)

[Claims] In a portable radio device having a casing for housing a radio unit and an antenna, a diversity antenna is formed by providing a recess in the casing and attaching a plurality of inverted F-shaped antennas each having a structure of bent plate conductor elements to the four parts. A portable radio device characterized by comprising: