JP3090242B2 - 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 small portable radio having a linear antenna, and more particularly to an antenna portion thereof. FIG. 8 shows a conventional portable wireless device of this type. Radio housing 11
A wireless device circuit 12 is housed inside, and a whip-type linear antenna 13 is set up outside the wireless device housing 11, and the antenna 13 is connected to the wireless device circuit 12 via a matching circuit 14 in the wireless device housing 11. It is connected. The length of the antenna 13 is
The matching circuit 14 is generally required unless the wireless device has an electrical length of about の of the wavelength of the operating frequency of the wireless device.

[0002] In order to obtain good radiation pattern performance, the length of the antenna 13 is preferably about half the wavelength used. This is because a standing wave of 波長 wavelength is placed on the antenna element, and the antenna current becomes almost zero at a portion where the antenna element is attached to the housing, so that the antenna is hardly affected by the housing. However, as described above, in the conventional portable wireless device, the feeding point is located at a portion where the antenna element is attached to the housing. Power must be supplied with high impedance, and a matching circuit 14 is required. Since the matching circuit 14 is composed of a coil and a capacitor, which are lumped constant elements, these resistances cause a loss, and the use of the matching circuit 14 reduces the efficiency of the antenna to 0.1.
Degrades by about 5 to 2 dB.

[0003] The conventional portable wireless device having the above-described antenna configuration has a good radiation pattern shape with little influence of the housing, but has a drawback that efficiency is deteriorated. In addition, it is difficult to obtain broadband characteristics because such a linear antenna is used, and there are proposals such as devising a matching circuit, or loading a coil in the middle or at the end of the antenna element. There was a disadvantage that it became complicated.

Further, when the whip antenna is of a retractable type, a mismatch occurs at the feeding point when the whip antenna is retracted, so that the whip antenna hardly operates as an antenna, and the gain is greatly deteriorated. Was. From such a point, the one shown in FIG. 9 (JP-A-4-120902)
Has been proposed. A dielectric plate 15 protrudes from the housing 11 and stands up. A strip conductor 16 s is formed in the center of one surface of the dielectric plate 15 along the longitudinal direction.
5, a wide ground conductor 16e is formed opposite to the strip conductor 16s.
And the ground conductor 16e, the microstrip line 1
6 are constituted. Linear conductors 17a and 17b connected to both sides of the end of the ground conductor 16e opposite to the housing 11 are formed along both side edges of the dielectric plate 15, and
The electrical lengths of a and 17b are １ ／ of the used wavelength.
One end of the coil-shaped conductor 18 is connected to the strip conductor 16s on the opposite side of the dielectric plate 15 from the housing 11. The electrical length of the coiled conductor 18 is set to １ ／ of the used wavelength.

[0005] Coiled conductor 18 and strip conductor 16
s, the ground conductor 16e and the linear conductor 17a,
If the feeding point is set between the connection point 17b and the antenna element, the current becomes almost zero at the portion where the antenna element is attached to the housing, and is less likely to be affected by the housing like the half-wavelength dipole antenna. Also, the dielectric plate 15 can be pushed down and housed in the housing 11, and in this state, the inner ends of the linear conductors 17a and 17b and the ground conductor 16e are short-circuited, and the coil-shaped conductor 18
Project outside, and only the coiled conductor 18 functions as an antenna.

[0006]

The principle of operation as an antenna in a state in which the dielectric plate 15 is pulled out is that the center conductor of the coaxial cable is protruded by 1/4 wavelength and the outer conductor is turned outward by 1/4 wavelength. The operation principle is the same as that of a vertical antenna having a cylindrical sleeve. Therefore, the antenna characteristic on the surface including the plate surface of the dielectric plate 15 is good, but the surface perpendicular to this surface and including the strip conductor 16s becomes unbalanced, an unbalanced current flows through the housing 11, and the radiation pattern is disturbed. And housing 1
If there is a loss in 1, the efficiency will be poor.

Further, the microstrip line 16 requires a dielectric plate to be interposed between the strip conductor 16s and the ground conductor 16e, and there is a problem that the loss increases when the thickness of the dielectric plate is reduced. Further, depending on the thickness of the dielectric plate 15, the width of the ground conductor 16e is
s is required to be at least about three times the width of the ground conductor 1
There is also a disadvantage that the linear conductors 17a and 17b are required on both outer sides of 6e and the width of the dielectric plate 15 is increased.

It is an object of the present invention to provide a portable radio having an antenna having a small radiation pattern disturbance, a high efficiency, and a high gain even when the antenna is housed. Another object of the present invention is to provide a portable wireless device having an antenna capable of easily obtaining wideband characteristics in addition to the above objects.

[0009]

According to the first aspect of the present invention, one end of a dielectric plate is protruded and attached to the outside of the radio device housing, and the one end of the dielectric plate is connected to the other end of the dielectric plate. A first linear antenna element having an electrical length of about 1/4 of the operating wavelength is formed on the dielectric plate, and a zigzag is formed on the opposite side of the first linear antenna element from the radio housing. A second antenna element having an electrical length of about の of the used wavelength (hereinafter simply referred to as wavelength) is formed on the dielectric plate, and the first linear antenna element and the second antenna element are mutually bent. A parallel (balanced) two-line feed line, one end of which is connected to the approaching inner end, is formed on the dielectric plate, and the other end of the parallel two-line feed line is connected to the radio circuit in the radio housing through the second feed line. It is connected.

[0010] The second antenna element is not a coil, it may be folded linear conductor zigzag formed in the dielectric plate.

[0011] Then, the dielectric plate is capable housed in radio housing, the connection between the parallel two linear feeder line and the second feeder line is performed by mutually slidable contact, radio housing the dielectric plate On the body
In a completely housed state, it is connected near the connection point between the first and second antenna elements and the parallel two linear feeders. In the state where the dielectric plate is incompletely stored, the connection near the connection point of the second feeder line is disconnected from the first antenna element side.

According to a third aspect , in the first aspect of the present invention,
Along with one linear antenna element, the length is different
A third linear antenna element is formed on the dielectric plate,
The opposite side of the linear antenna element from the radio unit housing is the first linear antenna.
Connected to the tenor element.

[0013]

The first linear antenna element on one side of the feeding point of the antenna has approximately one-quarter wavelength, the second antenna element is mainly composed of a zigzag conductor, and the impedance of the feeding point is low. By matching the characteristic impedance of the linear feeder line, a matching circuit is not required for connection to the radio device circuit, there is no loss due to the matching circuit, and the shape does not increase. The overall antenna length is also 1
Shorter than / 2 wavelengths.

Due to the presence of the first and third linear antenna elements, two resonance points are generated, and the band can be widened. Further, with the antenna housed in the housing, a relatively large antenna gain can be obtained by the second antenna element. Dielectric plate
In the storage state of, to adjust the depth of the storage
Therefore, the antenna gain can be made variable.

[0015]

FIG. 1 shows an embodiment of the invention of claim 1, and FIG.
The same reference numerals are given to portions corresponding to. Radio case 1
Reference numeral 1 denotes a case in which a relatively thin quadrangular shape is formed as in the conventional case, and a radio device circuit 12 is housed therein. In the present invention, one end of the dielectric plate 21 is attached to the radio device housing 11 and is provided so as to protrude outside. In this example, one end of the upper surface 11a of the wireless device housing 11 is substantially parallel to the side surface 11b adjacent to the upper surface 11a and has a thickness smaller than the thickness of the wireless device housing 11, ie, the width of each of the upper surface 11a and the side surface 11b. Is set up. The dielectric plate 21 has a small dielectric loss, for example, is made of a fluorine resin and retains a linear shape by itself. However, the dielectric plate 21 does not need to be rigid and may be flexible. On one surface of the dielectric plate 21, a first linear antenna element 22 extending from one end of the radio device housing 11 side to the other end of the dielectric plate 21
Is formed. A second antenna element 23 is provided on the side of the first linear antenna element 22 opposite to the radio device housing 11. In this example, the second antenna element 23 is formed on the dielectric plate 21 in a zigzag manner while extending back and forth in the width direction of the dielectric plate 21 in a direction opposite to the first linear antenna element 22. The electric length of the second antenna element 23 is made substantially equal to that of the first linear antenna element 22, and the dipole having an electric length of 波長 wavelength (used wavelength) between the first linear antenna element 22 and the second antenna element 23. Antenna 2
5. In this example, the first linear antenna element 2
The electrical length of No. 2 is approximately 1/4 wavelength.

A parallel 2 is arranged alongside the first linear antenna element 22.
A linear feed line 26 is formed on the dielectric plate 21, one end of the parallel two linear feed lines 26 is connected to a feed point of the antenna 25,
In other words, the lines 26a, 26 constituting the parallel two linear feeder lines 26
6b are connected to the inner ends of the first linear antenna element 22 and the linear part 23a, respectively. The two parallel feeders 26 are formed on the surface of the dielectric plate 21 on which the first linear antenna element 22 is formed, along the other side edge. The characteristic impedance of the parallel two-line feed line 26 is set substantially equal to the feed impedance of the antenna 25. The other end of the parallel two-line feed line 26 is connected to the wireless device circuit 12 through the second feed line 27 at the end of the dielectric plate 21 on the side of the wireless device housing 11 without using a matching circuit in this example. That is, the feed impedance at the center of the half-wave whip antenna is as low as about 75Ω, and the input impedance of a general internal circuit such as a filter and a receiver is also as low as about 50Ω. Therefore, if a connection is made to the internal circuit from the center of the antenna 25 corresponding to the whip antenna by the parallel two-linear feed line 26 and the second feed line 27 having low characteristic impedance, there is no need to pass through a matching circuit.

With such a configuration, power can be supplied to the dipole antenna 25 having an electrical length of 波長 wavelength without using a matching circuit. Accordingly, since the antenna 25 has an electrical length of １ ／ wavelength, the antenna current becomes zero at the lower end of the antenna 25, that is, at the end on the side of the housing 11, and the antenna 25 is not much affected by the housing 11. Since good radiation pattern characteristics are obtained and no matching circuit is required, there is no loss and little deterioration in efficiency. In addition, since it is configured in a flat plate shape, it can be relatively easily configured and can be made flexible like a normal whip antenna.

FIG. 2 is a partial modification of FIG.
The same reference numerals are given to portions corresponding to. In this example, the first linear antenna element 22 is provided on one surface of the dielectric
An antenna element 23 is formed on the other surface of the dielectric plate 21, a line 26a of the parallel two-line feed line 26 is formed on the surface on which the first linear antenna element 22 is formed, and a line 26b is formed on the second linear antenna element 22.
The line 26a and the dielectric plate 2 are formed on the surface on which the antenna element 23 is formed.
1 are formed to face each other.

FIG. 3 shows an embodiment in the case of wide band.
Parts corresponding to those in FIG. 1 are denoted by the same reference numerals. In this embodiment, the third linear antenna element 28 having a different length from the first linear antenna element 22 is replaced with the first linear antenna element 22.
The third linear antenna element 28 is connected to the first linear antenna element 22 on the side opposite to the wireless device housing 11. The electrical length of each of the first linear antenna element 22 and the third linear antenna element 28 is set to a quarter of each of the wavelengths λ ₁ and λ ₂ of the target resonance frequency as a design value. Adjust within 10%. According to this antenna, the first and third linear antenna elements 2 exhibit two-band resonance characteristics.
By selecting each of the lengths 2 and 28 and bringing both resonance frequencies close to each other, a wideband characteristic can be obtained.

FIG. 4 shows an embodiment in which the antenna can be housed freely. In this embodiment, the dielectric plate 21 can be stored in the wireless device housing 11. Figure 4 As shown in A, in this example the slits 30 are formed on the upper surface 11a of the housing 11, the dielectric plate 21 through the slit 30 is slid in close proximity facing the side surface 11b of the housing 11 and the housing 11
This is the case where it can be stored freely. Parallel two linear feeder 26
Contact piece 2 elastically contacting each of the lines 26a, 26b
9a, 29b are held in the housing 11, and the contact pieces 29a, 29
The second power supply line 27 is connected to the parallel two linear power supply lines 26 via 9b. One end of the second antenna element 23 is connected to the line 26.
a line 27b formed on the extension of the line b and connected to the line 26b in the lines 27a and 27b constituting the second feeder line 27
Is connected to the plus side of the radio circuit 12, and the line 27a is connected to the minus side (ground side) of the radio circuit 12.

As shown in FIG. 4B, in a state where the dielectric plate 21 is housed in the radio equipment housing 11, the contact piece 29a comes off the line 26a, and the contact piece 29b comes into contact with the second antenna element 23. The storage depth of the body plate 21 is selected. Also, at this time, the inner end of the dielectric plate 21 is in contact with the bottom plate 11c of the housing 11, and the dielectric plate 21 can be easily pulled out with the second antenna 23 portion protruding from the housing 11 of the dielectric plate 21. You.

In the state where the dielectric plate 21 is housed in the housing 11, the contact piece 29a is displaced from the line 26a, so that no power is supplied to the antenna from the minus 27a of the second power supply line. Inside, the minus side is connected to a wireless device housing 11 made of a conductive material.
That is, when viewed from the internal radio circuit 12, the plus side is connected to the second antenna element 23, and the minus side is connected to the radio housing 11 made of a conductive material. Therefore, since the second antenna element 23 has an electrical length of about ４ wavelength, it operates as a monopole antenna on the housing 11.

FIG. 5 is an explanatory diagram of the operation principle of the embodiment shown in FIG. As shown by the curve 31 in FIG. 5A, the current distribution in the state where the dielectric plate 21 is drawn out is such that the current rides over the first and second antenna elements 22 and 23,
Zeros at both ends. As described above, in the pulled-out state, power is supplied from the lower end of the dielectric plate 21,
6 to the center of the current distribution 31 to be fed with low impedance. On the other hand, the current distribution in the housed state is distributed over the second antenna element 23 and the housing 11 made of a conductive material as shown by a curve 32 in FIG. . Therefore, the current distribution does not change much in both the drawn state and the housed state, and both are matched, and a high gain is obtained. However, in this case, since the current is distributed over the entire housing, the current distribution is considerably different from that of the half-wavelength dipole antenna. In the state where the dielectric plate 21 is stored, the contact piece 29a is connected to the first linear antenna element 2 of the line 26a.
2, the antenna current rides over the first and second antenna elements 22 and 23 in the same manner as the curve 31 even if the housing 11 is made of a non-conductive material.
Since it radiates through the non-conductive casing 11, it operates as an antenna in the housed state. On the other hand, in this case, when the housing 11 is made of a conductive material, although the contact piece 29a is in contact with the second antenna element 23, current flows on the antenna. 1 antenna element 2
No radiation from 2 Therefore, as shown in FIG.
Is emitted, so that it does not matter if the contact piece 29a is off the line 26a.

In the embodiment shown in FIG. 4A, with the dielectric plate 21 housed, the inner end of the parallel two-line feeder line 26 elastically contacts the short-circuiting piece 33 as shown in FIG. The piece 29a does not come off the track 26a,
a. The numbers in the other figures are
Corresponds to A. With this configuration, even when the dielectric plate 21 is housed, the plus line 27 of the second power supply line 27 is also provided.
From b, the 1/4 wavelength monopole antenna constituted by the second antenna element 23 is connected, and matching is achieved. Further, since the inner end of the parallel two-line feed line 26 is short-circuited and the length of the feed line is about 1/4 wavelength, the feed point, that is, the side of the parallel two-line feed line 26 from the contact pieces 29a and 29b. And the impedance becomes infinite,
No current flows on the side of the parallel two-line feeder 26. In this case, the current distribution when the housing 11 is a non-conductive material is shown by a curve 34 in FIG. 6B. That is, it operates as a half-wave dipole antenna. Also in this case, if the housing 11 is made of a conductive material, a current flows through the first antenna element 23 and the housing 11 in the housed state, and operates as an antenna.

As shown in FIG. 7A by assigning the same reference numerals to parts corresponding to those in FIG. 6, the second antenna element 23 may be formed in a coil shape instead of a zigzag shape. That is, the thickness of one end of the dielectric plate 21 is increased, the coil 23b is wound around the thick portion 21a, and one end of the coil 23b is connected to the extension 23a of the line 26b on the dielectric plate 21 to form the second.
Here, the antenna element 23 is used. The coil 23b may be formed in a spiral shape on one surface of the dielectric plate 21 or the coil 2b.
3b may be formed as a cylindrical spiral, and may hold the coil shape by itself and protrude from one end of the dielectric plate 21. Even when the second antenna element 23 is formed in a coil shape, as shown in FIG. 2, the lines 26a and 26b of the parallel bilinear feed line 26 are separately formed on one surface of the dielectric plate 21 and the other surface. Alternatively, the third linear antenna element 28 may be provided side by side with the first linear antenna element 22 as shown in FIG. Further, as shown in a horizontal cross-sectional view of the dielectric plate 21 in FIG. 7B, one of the lines 26a is connected and fixed along a reinforcing wire 36 made of a thin line having a diameter of, for example, 0.5 mm to mechanically move the dielectric plate 21. It may be reinforced. As shown in FIG. 7B, the whole of the dielectric plate 21, the first linear antenna element 22, the second antenna element 23, and the two parallel linear feeders 26 may be covered with a dielectric protective layer 37. . This protective layer 37
Can be attached by, for example, a dielectric mold.

[0026]

As described above, according to the present invention, since the second antenna element 23 has a zigzag line,
The total antenna length can be shortened, and the electric length of the antenna 25 acts as a dipole antenna having a half wavelength, and the feed point having a low impedance is connected to the second feed line 27 through the parallel bi-linear feed line 26. Connected to the radio circuit 1 without passing through a matching circuit.
2, no loss in the matching circuit, high efficiency can be obtained, and the device can be made compact. Further, the current on the antenna 25 becomes zero near the connection point with the housing 11.
Therefore, it is hardly affected by the housing, and the radiation pattern characteristics are good.

When the antenna is formed on both sides of the dielectric plate 21 as shown in FIG. 2, the width of the dielectric plate 21 can be reduced. Further, by providing the third linear antenna element 28, two resonance frequencies are provided,
Broadband characteristics can be obtained. Further, according to the present invention, the antenna can be housed in the housing, and in the housed state, the antenna operates as a quarter-wave monopole antenna or a half-wave dipole antenna, so that a high gain can be obtained and the radio apparatus has a low impedance. Connected to circuit 12.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an appearance part of the present invention .

FIG. 2A is a perspective view showing an external part of the present invention in which a parallel two linear feeder is formed with a dielectric plate interposed therebetween, and FIG. 2B is a partial perspective view of FIG. 2A viewed from the opposite side.

FIG. 3 shows an embodiment of the present invention in which a third linear antenna element is added.
The perspective view which shows a viewing part .

4A and 4B show an embodiment of the present invention in which a dielectric plate can be housed . FIG. 4A is a perspective view of a state where an antenna is pulled out and a front plate of a housing 11 is removed, and FIG. 4B is a state where the antenna is completely housed. It is a perspective view.

FIGS. 5A and 5B are diagrams showing antenna current distributions in the embodiment shown in FIGS. 4A and 4B, respectively.

FIG. 6A is a perspective view of another example in which the front plate is removed in an antenna housed state, and FIG. 6B is a view showing an antenna current distribution of the embodiment shown in FIG. 6A.

FIG. 7A shows a short-circuiting device arranged at the lower end of the parallel linear feeder.
Location was FIG, B is a horizontal enlarged cross-sectional view of the dielectric plate 21 in the various embodiments.

FIG. 8 is a perspective view showing a conventional portable wireless device.

FIG. 9 is a perspective view showing a conventional portable wireless device obtained by improving the wireless device of FIG. 1;

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01Q 1/24 H01Q 1/38 H01Q 9/26 H04B 1/38

Claims (3)

(57) [Claims] 1. A wireless device housing, a wireless device circuit provided in the wireless device housing, and a wireless device housing capable of being housed in and out of the wireless device housing.
And the two parallel feeders and the first and second antenna elements are shaped.
A dielectric plate formed and extending from an intermediate portion of the dielectric plate to one edge thereof,
The first linear antenna element having an electrical length of about 1/4 of the length.
And extending from the middle part of the dielectric plate to the other edge,
It has an electrical length of about 1/4 of its length and is folded in a zigzag
The second antenna element, and the first linear antenna element and the second antenna element.
One end is connected to the inner ends that are close to each other, and the other end is
The two parallel feeders terminating at one edge of the body plate, and one end of each of the two ends according to the movement of the dielectric plate.
Slidably connected to each of the parallel two linear feeders
And the dielectric plate is sufficiently housed in the wireless device housing.
And one of the one ends is connected to the second antenna element side.
And the other of the one end is connected to the second antenna element.
The dielectric plate is not connected to the slave side, and the dielectric plate is sufficiently taken out of the wireless device housing.
In the state, each of the one ends is the parallel two linear feeder.
The other end of the line is connected to the radio
And a second power supply line connected to the circuit . 2. The first linear antenna element and one of the two parallel feeders connected to the first linear antenna element are formed on one surface of the dielectric plate, and are parallel to the other surface of the dielectric plate. The portable wireless device according to claim 1, wherein the other line of the two-line feeder line is formed. 3. A third linear antenna element substantially parallel to the first linear antenna element and having a different length from the first linear antenna element is formed on the dielectric plate, and the third linear antenna element is connected to the radio device. The portable wireless device according to claim 1, wherein the portable wireless device is connected to the first linear antenna element on a side opposite to a housing.