JPH0748612B2 - Portable radio - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable wireless device having a tie-pole antenna attached, and more particularly to a structure of a dipole antenna and a mounting position on a wireless device housing.

SUMMARY OF THE INVENTION According to the present invention, in a portable radio equipped with a dipole antenna, both ends of the dipole antenna are bent so that a central portion of the element is parallel to the back surface of the radio housing and is orthogonal to both side surfaces. This is a portable wireless device mounted in the wireless device housing with improved sensitivity to vertically polarized waves in a call state.

Prior Art FIG. 13 is a perspective view showing an example of a conventional portable wireless device, in which a 1/4 wavelength whip antenna is vertically projected from a portable wireless device housing 2. A handset 3 and a transmitter 4 are mounted on the front surface of the portable radio casing 2, and the built-in radio unit and the antenna element 1 are connected at a feeding point 5.
A curve 6 shown by a dotted line in the figure shows a current distribution on the antenna element 1. In this portable wireless device, since the antenna element 1 operates by using the portable wireless device housing 2 as a ground conductor, an antenna current flows through the portable wireless device housing 2 so that a person can carry the portable wireless device housing 2 together.
When the handheld device is operated with a hand, there is a disadvantage that the current flowing in the portable wireless device housing 2 leaks to the human body and the antenna characteristics are greatly deteriorated.

As shown in FIG. 14, the portable wireless device in which the antenna element 1 is a 1/2 wavelength dipole antenna and a feeding point 5 is provided in the center thereof has a current distribution on the antenna element 1 of a curve 6 '.
The portable wireless device housing 2 has the antenna element 1 as shown in FIG.
Since it is not used as a ground conductor of the portable radio device, and is arranged so that the position where the antenna current amplitude is almost 0 is close to the portable radio device casing 2, the current flowing in the portable radio device casing 2 is reduced. In addition, the characteristic deterioration due to the current leakage when being held in the hand is extremely small.

If you want to hold a call with these portable radios in your hand, make a call with the handset 3 part on your ear and the handset 4 part close to your mouth, as you normally would on a handset. Is to do. That is, in the call state, the portable wireless device housing 2 is used while being tilted considerably from the upright state, and accordingly, the antenna element 1 is also tilted.
The angle of inclination can range from 60 to 70 °.

On the other hand, in mobile communication, vertical polarization is often used in order to simplify the configuration of the mobile station antenna. Many wireless systems, such as car phones, taxi radios, MCA systems, and personal radios, use vertically polarized waves.

Therefore, the above-described conventional portable wireless device has a drawback that the antenna sensitivity is significantly lowered due to the inclination of the antenna in a call state.

This drawback is due to the fact that two monopole antenna elements 1 as shown in FIG. 15 are provided, and a portable radio device for diversity reception (Taga, Mishima "Study on antenna for portable device" Showa
The same applies to the 56th academic year's financial resources 8-204 (see Sho 56-4). In this portable radio, the correlation between the outputs of the two antennas can be made almost zero by setting the distance between the two antennas to about 0.125λ (λ is the wavelength of the used frequency) (Yamada, Sawaya et al. "Experiment of Switching Diversity for Mobile Communication Using Monopole Antenna with Small Element Spacing", 1987 Tohoku Branch of the Institute of Electrical Engineers, 2B15 (Sho 57), etc.).

Further, in each of the above-mentioned various conventional portable wireless devices, since the antenna is projected from the wireless device housing, breakage or the like is likely to occur and the reliability of the wireless device is deteriorated.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention solves the above-mentioned conventional drawbacks, prevents characteristic deterioration due to leakage of antenna current when held in a hand, and tilts the radio housing in a call state. Also provides a portable wireless device having an antenna structure which has good sensitivity to vertically polarized waves and is less likely to cause antenna breakage.

The portable wireless device of the present invention is a portable wireless device in which a dipole antenna is attached to a wireless device housing in which a wireless device is housed and a transmitter and a receiver are mounted on a front surface, wherein the dipole antenna is a wireless device housing. Of the element, which is arranged in a direction parallel to the back surface of the element and orthogonal to the side surfaces, and is bent at a right angle to the element central part.
It is characterized in that it is composed of two element ends.

Embodiments of the Invention Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing a first embodiment of the present invention.
That is, the feeding point 5 is provided at the center of the element central portion 10 of the dipole antenna, and both end portions thereof are bent at right angles at points B and C to form two element end portions 11 and 21. Element central part 10,
The dimensions of the element ends 11 and 21 are about the length of the operating frequency band.
It is configured to have a half wavelength and operates as a dipole antenna. The element central portion 10 is arranged so as to be parallel to the line of intersection between the back surface 9 and the top surface 8 of the portable wireless device housing 2. Therefore, the directions are orthogonal to both side surfaces. One of the element ends 11 is the back surface 9 of the portable wireless device housing 2.
And a direction parallel to the side surface and orthogonal to the bottom surface 14, and the other element end portion 21 is bent in a direction parallel to the side surface and orthogonal to the back surface 9. The element end 11 is attached to the back surface 9 by the antenna element support 7.
And the element end 21 is fixed to the top surface 8 by the antenna element support 7 so that the entire antenna can be attached to each surface of the portable wireless device housing 2 with a gap. In the figure, A represents the tip of the element end 11, D represents the tip of the element end 21, and curve 6 represents the current distribution on the antenna element.

FIG. 2A is a rear view of the portable wireless device of this embodiment in a call state, in which the portable wireless device housing 2 is tilted sideways and the element central portion 10 is close to vertical. FIG. 6B is a vector diagram showing the relationship between the sensitivity 12 for the vertically polarized wave component and the sensitivity 13 for the horizontally polarized wave component when the tilt angle θ is large. It shows that the sensitivity to the component 12 is higher. On the other hand, when the conventional portable wireless device is tilted sideways as shown in FIG. 7C, the sensitivity 12 to the vertical polarization component increases as the tilt angle θ increases as shown in FIG. It is getting smaller. That is, the present embodiment has an effect that the sensitivity to vertical polarization is high in a call state. This is because the element central portion 10 having the feeding point 5 is a portion where the current distribution of the dipole antenna becomes large, and this portion stands up close to vertical in a talking state.

In addition, in the present embodiment, since the respective parts of the dipole antenna are arranged so as to be orthogonal to each other, in any part, regardless of the state in which the portable wireless device housing 2 is placed, vertical polarization with respect to the vertically polarized wave is obtained. Have sensitivity. For example, when the portable wireless device housing 2 is in the upright state, the element end 11 is sensitive to the vertically polarized wave, and when the portable wireless device housing 2 is tilted with the handset 3 sideways, The element end 21 has sensitivity when the central portion 10 is laid down with the handset 3 down.
Also, when the handset 3 is tilted upward and a call is made, the element ends 11 and 21 have sensitivity. As described above, the element central portion 10 has a great sensitivity in a call state. Therefore, the present embodiment has an advantage that the sensitivity to the vertically polarized wave does not extremely decrease regardless of the state of the portable wireless device housing 2 placed. This is extremely advantageous in the standby state.

FIG. 3 is a perspective view showing a second embodiment of the present invention. In this case, a dipole antenna with a total length of 1 / 2λ is bent in a U shape, and the central portion 10 of the element is parallel to the line of intersection between the back surface 9 and the top surface 8 and is farthest from the handset 3. As shown in FIG. Therefore, the directions are orthogonal to both side surfaces. Both of the element end portions 11 and 21 are bent in a direction orthogonal to the back surface 9 and parallel to both side surfaces, and the antenna element support 7 allows the top surface 8 to be bent.
It is fixed at a fixed distance from. In this case, since the element ends 11 and 21 are arranged in parallel, the element end 11
Since the currents flowing in and 21 are in opposite directions and the radiated electromagnetic fields are in opposite phases and cancel each other, the sensitivity is lower than that in the first embodiment, but the main purpose is to increase the antenna gain in a talking state. Is achieved.

FIG. 4 is a front view in the case where the portable wireless device is held in the hand and the handset 3 is put on the ear, and the transmitter 4 is placed near the mouth to make a call. The central part 10 of the element stands nearly vertically. FIG. 6B is a diagram showing the relationship between the sensitivity 12 for the vertical polarization component and the sensitivity 13 for the horizontal polarization component in this case, and the sensitivity 12 for the vertical polarization component may increase as the tilt angle θ increases. To be understood.

FIG. 5 is a perspective view showing a third embodiment of the present invention,
In this case, a dipole antenna with a total length of 1 / 2λ is bent in a U shape, and the central portion 10 of the element is parallel to the line of intersection between the back surface 9 and the top surface 8 and is farthest from the handset 3. Thus, it is arranged at a constant distance from the back surface 9. Therefore,
The directions are orthogonal to both sides. Both the element ends 11 and 21 are parallel to the back surface 9 and both side surfaces, and
It is bent in a direction orthogonal to the bottom surface, and is fixed at a constant distance from the back surface 9 by the antenna element support 7. In this case, since the element ends 11 and 21 are arranged in parallel, the currents flowing through the element ends 11 and 21 are in opposite directions, and the radiated electromagnetic fields cancel each other out of phase.
Although the sensitivity is lower than that of the first embodiment, the main purpose of increasing the antenna gain in the talking state is achieved.

FIG. 6 is a rear view showing a call state of the portable wireless device, and the element central portion 10 stands nearly vertically like the above-mentioned embodiment. FIG. 6B is a diagram showing the relationship between the sensitivity 12 for the vertical polarization component and the sensitivity 13 for the horizontal polarization component in this case, and the sensitivity 12 for the vertical polarization component may increase as the tilt angle θ increases. To be understood.

In each of the above-described embodiments, in addition to the effect that the sensitivity does not decrease in a call state, since the element central portion 10 is arranged at the farthest position with respect to the handset 3, when the handset 3 is put on the ear, The configuration is such that the variation in antenna characteristics due to the influence of the human body is minimized.

According to the field experiment in the 900 MHz band, the decrease in the antenna gain in the talking state was about 2 dB in the dipole ratio in the configuration of FIG. 3, and about 6 dB in the conventional example of FIG.
That is, it was confirmed that the present invention can improve the antenna gain by about 4 dB as compared with the conventional example.

FIG. 7 is a perspective view showing a fourth embodiment of the present invention,
Two dipole antennas similar to the above are attached. The element central portions 10 and 10 'are mounted in parallel at positions near the upper and lower edges of the back surface 9, respectively, and
11, 21, 11 ', 12' and the like are fixed to the portable wireless device housing 2 by the antenna element support 7. Various combinations of the bending directions of the element end portion 11 and the like are possible. In this case as well, since the element central portions 10 and 10 'are both mounted in a direction having sensitivity in a talking state, the same effect as that of the above-described embodiment is obtained, and two more elements are provided than in the conventional example shown in FIG. By increasing the antenna spacing, there is an effect that the correlation between the outputs of both antennas can be lowered.

8 to 10 are perspective views showing fifth to seventh embodiments of the present invention, respectively. Figure 8 (A), (B), (C)
In both cases, the element end portions 11 and 21 are constituted by plate-shaped conductors, and their longitudinal directions are both perpendicular to the element central portion 10. By increasing the width of the plate conductor,
This has the advantage that the resonant frequency of the antenna can be kept constant and the longitudinal dimension of the element ends 11 and 21 can be shortened.Moreover, the element ends 11 and 21 are equivalently thickened to improve the band characteristic of the antenna. Has the effect of In FIG. 3A, the longitudinal direction of the element end portion 11 is orthogonal to the bottom surface of the portable wireless device housing 2, and the longitudinal direction of the element end portion 21 is orthogonal to the back surface 9. FIG. 2B shows a direction in which the longitudinal directions of the element end portions 11 and 21 are both orthogonal to the back surface 9, and FIG.
The longitudinal directions of 1, 21 are both directions orthogonal to the bottom surface of the portable wireless device housing 2. As a matter of course, each of them has the effect of improving the gain during a call as in the case described above. In these figures, the feeding structure of the central portion 10 of the element is different from that shown in FIG. 1, FIG. 3, and FIG. 5, but this is for matching the tie-pole antenna with the feeding line. Therefore, a structure corresponding to the feeding shape when performing T matching (for balanced feeding line), γ matching (for unbalanced feeding), etc., which is well known in the past, or when a balun or the like is loaded is used. It is shown. It should be noted that the operation and effect of the present invention are the same regardless of which power supply structure is adopted.

9 (A), (B), and (C) are respectively the sixth embodiment of the present invention.
Is a perspective view showing an example of, both of the element central portion 10,
Element end portions 11, 12 and the like are formed on a dielectric plate 15 by printing. Although the directions (A), (B), and (C) of the elements are different from each other in the element end portions 11 and 21, respectively, they have the same effects as described above and can reduce the manufacturing cost during mass production. is there.

10 (A) and 10 (B) are perspective views showing a seventh embodiment of the present invention, in which a step 16 is provided on the back surface 9 and all or part of the antenna is arranged at that portion. It is a thing. FIG. 7A shows the element end portion 11 alone arranged in the step portion of the back surface 9, and FIG. 9B shows the entire antenna arranged in the step portion of the back surface 9. Both have the same effects as described above, and the portable radio housing 2 of the antenna
Since it is possible to reduce the protrusion from, there is an advantage that the portable wireless device can be configured compactly.

FIG. 11 is a perspective view showing an eighth embodiment of the present invention. In this case, the element end portions 11 and 21 are each composed of two conductor elements arranged in parallel. By making the dimensions of the two conductor elements different, it is possible to obtain antenna characteristics having a plurality of resonance frequencies. The feeding point 5 is connected to the feeding coaxial line 17. Figure 12 shows
11 is a diagram showing the results of actual measurement of the return loss characteristic of the embodiment of the configuration of FIG. 11 in the 900 MHz band, the return loss characteristic 18 has a plurality of resonance points 19, each resonance point 19 is an element end 11 or 21.
The desired frequency can be set by changing the dimensions of the two conductor elements. As a result, it is possible to compensate for the narrowing of the band of the antenna element caused by disposing the dipole antenna element near the surface of the portable wireless device housing 2. This is an extremely advantageous configuration when applied to a system in which is separated.

As described above, in the present invention, the end portion of the dipole antenna is bent, and the central portion of the element is arranged parallel to the back surface of the housing of the portable wireless device and orthogonal to both side surfaces. Therefore, there is an effect that the sensitivity to vertically polarized waves is improved in a call state in which the portable wireless device housing is tilted. Further, since the antenna has a structure in which the portion protruding from the portable wireless device housing is small, it can be easily covered with the antenna cover, and it is possible to provide a highly reliable portable wireless device by preventing breakage of the antenna element and the like. it can.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention, and FIG. 2 is a rear view showing a communication state of the above-mentioned embodiment and a conventional portable radio, and its inclination angle and sensitivity to vertical and horizontal polarization components. FIG. 3 is a perspective view showing a second embodiment of the present invention, and FIG. 4 is a front view showing the usage state thereof and a relationship between the tilt angle and the sensitivity to vertical and horizontal polarization components. FIGS. 5 and 6 are perspective views showing a third embodiment of the present invention, and FIG.
FIG. 7 is a rear view showing its use state and a view showing the relationship between the tilt angle and the sensitivity to vertical and horizontal polarization components. FIG. 7 is a perspective view showing a fourth embodiment of the present invention, and FIGS. The drawings are perspective views showing fifth to eighth embodiments of the present invention, FIG. 12 is a view showing an example of characteristics of the eighth embodiment, and thirteenth to fifteenth embodiments.
Each of the drawings is a perspective view showing an example of a conventional portable wireless device. In the figure, 1: antenna element, 2: portable wireless device housing, 3: receiver, 4: transmitter, 5: feeding point, 6: curve, 7: antenna element support, 8: top surface, 9: back surface , 10: Element center part, 11, 21: Element end part, 12: Sensitivity to vertical polarization component, 13: Sensitivity to horizontal polarization component, 14: Bottom surface, 15: Dielectric plate, 16: Step, 17: Antenna Coaxial line for feeding, 18: return loss characteristic, 19: resonance point.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ikuo Takekawa 1-2356 Takeshi, Yokosuka City, Kanagawa Prefecture Yokosuka Electro-Communications Research Laboratories, Nippon Telegraph and Telephone Public Corporation (72) Koichi Tsunekawa 1-2356 Takeshi City, Yokosuka Kanagawa Prefecture Nippon Telegraph and Telephone Corporation Telephone Public Corporation Yokosuka Electro-Communications Research Laboratory (56) References JP-A-60-7204 (JP, A) Actual development 55-26987 (JP, U) Actual development 59-106205 (JP, U)

Claims (7)

[Claims] 1. A portable radio in which a dipole antenna is attached to a radio housing in which a radio is housed and a transmitter and a receiver are mounted on the front surface, the dipole antenna being parallel to the back of the radio housing. An element central portion which is arranged in a direction orthogonal to both sides and receives a signal of an electric field parallel to its longitudinal direction, and an electric field which is bent at a right angle to the element central portion and is parallel to each longitudinal direction. A portable wireless device comprising: two element ends for receiving the signal of. 2. The portable wireless device according to claim 1, wherein the two element ends are arranged in parallel with the back surface or the bottom surface of the wireless device housing. 3. The portable wireless device according to claim 1 or 2, wherein two dipole antennas are attached. 4. The portable wireless device according to claim 1, wherein at least one of the two element ends is constituted by a plurality of conductor elements arranged in parallel. What is characteristic. 5. The portable wireless device according to any one of claims 1 to 4, wherein the two element ends are plate conductors. 6. The portable wireless device according to any one of claims 1 to 5, wherein a step is provided on a back surface of the wireless device housing, and at least one of the two element end portions is the above-mentioned. Characterized by being arranged in a stepped portion. 7. The portable wireless device according to any one of claims 1 to 6, wherein a dielectric is provided in all or a part of a gap between the dipole antenna and a surface of a housing of the wireless device. What to do.