JP3096095B2 - Portable radio - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable wireless device, and more particularly to a portable wireless device having an antenna structure in which a gain is hardly deteriorated even when used near a human body or the like.

[0002]

2. Description of the Related Art FIG. 7 is a view showing an example of a conventional portable radio, in which (a) is a dielectric-coated antenna, (b) is a helical antenna, and (c) is a portable radio having a linear antenna. Is shown. In the figure, 27 is a dielectric rod, 28
Is a linear metal antenna element, 29 is a metal housing, 30 is an antenna holding dielectric rod, 31 is a helical metal antenna element, 32 is a metal housing, 33 is a linear metal antenna element, 3
Reference numeral 4 denotes a metal housing.

In FIG. 1A, a linear antenna element is covered with a dielectric material to shorten the antenna element. The dielectric element resonates at an electric length of about 1/4 wavelength, and the dielectric element loses a little. The gain is low. In this case, the radiation pattern on the horizontal (XY) plane is non-directional, that is, circular. Also, the one shown in FIG. 3B is a helical winding of the antenna wire as a miniaturization method.
The radiation pattern on the -Y) plane is non-directional. Figure (c)
Are the most common ones, and are examples in which a quarter-wave linear antenna is used. In this case, the antenna gain does not decrease, but the radiation pattern on the horizontal (XY) plane is also non-directional.

[0004]

As described above, all conventional portable radios have omnidirectional antennas, so when handled near a human body, radiated power in the direction of the human body is absorbed and reflected, and There is a disadvantage that the characteristics are degraded and the gain is greatly reduced.

FIG. 4 shows a free space and a talking state when a conventional antenna as described above is attached to a portable radio having a volume of about 100 cc (a person is holding a radio and talking with his ear). 7 shows a change in gain. In the figure, numeral 13 is 1
In the case of a 波長 wavelength linear antenna, reference numeral 14 denotes a case of a helical antenna. As is clear from this figure, the 状態 wavelength antenna is -13 dBd and the helical antenna is -14.7 dBd, which is extremely low in a talking state.

As described above, the conventional portable wireless device has a drawback that the antenna gain becomes extremely low when worn on a human body (during a call) because the antenna radiation pattern is omnidirectional in a horizontal plane. Further, in the conventional antenna, since the shape substantially determines the resonance frequency, it is necessary to change the antenna shape to adjust the resonance frequency, and there is a problem that it takes much time and effort.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem. It is an object of the present invention to reduce the antenna gain even in the vicinity of a radio wave obstruction such as a human body and to have good characteristics. Another object of the present invention is to provide a portable wireless device having an antenna that can easily adjust a resonance frequency.

[0008]

According to the present invention, a conductor plate is attached to a rod-shaped dielectric along the longitudinal direction thereof,
At least one linear or band-shaped conductor is attached to the surface of the dielectric facing the conductor plate, and an antenna is formed by connecting one point on the conductor and one point on the conductor plate with a conductor. A portable wireless device configured to supply power with one end of the conductor being a plus side and one end of the conductor plate being a minus side.

[0009]

In the portable radio of the present invention, the antenna has the above-mentioned structure, so that the antenna radiation pattern becomes unidirectional, and even when used near a human body, radiation on the human body side is suppressed to a low level. Therefore, it is possible to realize a portable wireless device which has less deterioration in antenna gain during a call and has good characteristics. Further, it is possible to easily change the resonance frequency without significantly changing the antenna structure. Hereinafter, the operation and the like of the present invention will be described in detail based on examples.

[0010]

FIG. 1 shows an embodiment of the present invention.
FIG. 2 shows a perspective view of the portable wireless device. In the figure, 1 is a dielectric rod, 2 is a linear metal (hereinafter also referred to as a linear metal), 3 is a flat metal mounted on a surface opposed to the linear metal 2, and 4 is a linear metal Metal wire connecting the flat metal and
Reference numeral 5 denotes a feeding point, 6 denotes a metal housing, 7 denotes a coaxial feeding line, 8 denotes a receiver, and S denotes a distance between a connection point of the metal wire and a housing surface (the lower end of the antenna). . The core wire of the power supply line 7 is connected to the linear metal 2, the jacket is connected to the metal housing 6, and the flat metal 3 is connected to the metal housing 6. Therefore, the linear metal 2 is supplied as a positive power and the flat metal 3 is supplied as a negative power.

FIG. 2 shows the return loss characteristics of this portable radio.
FIG. 3 shows the radiation pattern characteristics. 3 represents an E９ component and 10 represents an EΦ component. In this case, the dielectric rod has a relative permittivity of 17, a size of 10 × 5 × 60 mm (X × Y × Z), and S is 25 mm. As is apparent from these figures, the resonance resonates at 920 MHz at only 60 mm, and the radiation pattern has a difference between the maximum and minimum levels of the EΘ component of about 8 dBd, and becomes a unidirectional pattern.

FIG. 4 is a diagram showing the antenna gain in the case where the antenna is set upright in free space (in the figure, simply referred to as free space) and in the state of talking. (This figure is also mentioned in the section of “Problems to be Solved by the Invention” earlier.) In the figure, 13 is a （wavelength (85 mm) linear antenna, 14 is a 60 mm helical antenna, and 15 is this embodiment. The case of the dielectric antenna of the example is shown. As shown in this figure, in the free space, the 1/4 wavelength antenna is the highest at 1 dBd, and then the dielectric antenna of this embodiment is 2 dBd.
In the dielectric antenna of this embodiment, the highest is -12 dBd. Thus, it can be seen that the antenna of the present invention has higher characteristics than other antennas during a call.

Another feature of the present antenna is that the resonance frequency can be easily changed. FIG. 5 shows the relationship of the resonance frequency when the distance S between the connection metal wire 4 and the housing surface (the lower end of the antenna) is changed in the antenna having the same dimensions as the first embodiment. As is apparent from this figure, the antenna resonance frequency is set to about 300 MHz by the distance S.
z can also be varied. That is, the resonance frequency can be changed by adjusting S without changing the outer dimensions of the antenna at all. Therefore, it is possible to adjust the antenna very easily.

As described above, in the present embodiment, since the radiation pattern can be made unidirectional, good characteristics can be obtained with little deterioration of the gain characteristic during a call, and the antenna resonance frequency can be easily adjusted. A portable wireless device can be realized.

FIG. 6 is a view showing another embodiment of the present invention, in which 16 is a dielectric rod, 17 and 18 are linear metals, respectively, and 19 is mounted on a surface opposed to the linear metals 17 and 18. A flat metal, 20 is a metal wire connecting the linear metal 17 and the flat metal 19, 21 is a metal wire connecting the linear metal 18 and the flat metal 19, and 22 and 23 are feed points, respectively.
4 and 25 each represent a receiver or a transmitter. In this embodiment, when there are two linear metals, the system operates in two systems connected to the respective linear metals, and when two systems are accessed, transmission / reception is performed separately, or reception is performed. This is an example of a case where a configuration such as a baseband diversity system is performed using two devices.

In this embodiment, since the basic structure is the same, the effect is not different from that of the above embodiment, and the antenna characteristics are not deteriorated when worn on a human body. Further, by changing the positions of the connecting metal wires 20 and 21, it is possible to easily resonate the two antennas at different frequencies. Of course, the number of linear metals is not limited to two, but may be plural. According to the present embodiment, a plurality of antennas having good characteristics when approaching a human body and easily resonating at arbitrary different points can be integrally formed.

[0017]

As described above, according to the present invention,
Since the antenna radiation pattern is unidirectional and antenna radiation on the human body side when used near the human body can be suppressed low, a portable wireless device with less antenna gain deterioration during a call can be realized. Further, there is an advantage that the adjustment is easy because the resonance frequency can be easily changed without changing the structural dimensions of the antenna.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of the present invention.

FIG. 2 is a diagram illustrating return loss characteristics of the antenna according to the embodiment.

FIG. 3 is a diagram illustrating radiation pattern characteristics of the antenna according to the embodiment.

FIG. 4 is a diagram illustrating gain characteristics of an antenna.

FIG. 5 is a diagram showing a relationship between a connection point between a flat metal plate and a metal wire and a resonance frequency.

FIG. 6 is a diagram showing another embodiment of the present invention.

FIG. 7 is a diagram illustrating an example of a conventional portable wireless device.

[Explanation of symbols]

1,16 Dielectric rod 2,17,18 Linear metal 3,19 Flat metal 4,20,21 Metal wire connecting linear metal and flat metal 5,22,23 Feed point 6,26 Metal housing Body 7 Coaxial feed line 8 Receiver 9 EΘ component 10 EΦ component 13 Characteristics of 1/4 wavelength (85 mm) linear antenna 14 Characteristics of 60 mm helical antenna 15 Characteristics of dielectric antenna of this embodiment 24, 25 Receiver or Transmitter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-242029 (JP, A) JP-A-3-183201 (JP, A) JP-A-4-120902 (JP, A) 160614 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01Q 1/24

Claims (1)

(57) [Claims] 1. A conductor plate is attached to a rod-shaped dielectric along a longitudinal direction thereof, and at least one linear or band-shaped conductor is attached to a surface of the dielectric facing the conductor plate. An antenna formed by connecting one point on the conductor and one point on the conductor plate with a conductor, wherein power is supplied with one end of the conductor being a plus side and one end of the conductor plate being a minus side. And portable radio.