JP3119553B2 - Radio antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna for a radio, which comprises a combination of a linear antenna and a coil element.

[0002]

2. Description of the Related Art In portable radios such as portable telephones, portable antennas have been reduced in size and weight, such as external dimensions of a housing, in consideration of portable convenience. ing. Such a small antenna is required to be able to always respond to a call signal from the other party when stored as a bidirectional communication means, and there is a strong demand for improvement in antenna sensitivity. Conventionally, a built-in antenna element is separately provided so as to be able to respond even when the antenna is stored, and a method of appropriately switching these antennas has been considered, but the structure is complicated and the overall shape is enlarged. For example, Japanese Patent Application Laid-Open No. 1-101702 or 1-10
As disclosed in Japanese Unexamined Patent Publication No. 703-703, there has been proposed an antenna in which when an antenna is housed in a housing, power is directly supplied to a loading coil unit attached to the antenna to secure the sensitivity of the antenna.

FIG. 6 shows the structure of a conventional small antenna of this type.
9 will be described with reference to FIGS. 6 and 7.
Is related to Japanese Patent Application Laid-Open No. 3-245603, in which a required number of turns having an electrical length of approximately 1/4 of the resonance wavelength is loaded onto the tip of a linear antenna 8 having an electrical length of approximately 1/4 of the resonance wavelength. When the linear antenna 8 is extended, the linear antenna 8 and the loading coil 70 are connected to each other.
When the linear antenna 8 is housed in the housing 1 as shown in FIG. 7, it protrudes upward from the housing 1 so as to function as an antenna having an electrical length of about １ ／ of the resonance wavelength. Only the loading coil 70 is configured to function as the shortened antenna 7 having an electrical length of about １ ／ of the resonance wavelength. In the drawing, reference numeral 9 denotes a circuit board, reference numeral 90 denotes a power supply unit, and reference numeral 91 denotes a contact fitting. When the linear antenna 8 is housed in the housing 1, a metal portion 81 is provided.
Contacting the contact fitting 91, the loading coil 7
0 is supplied.

In the second prior art example shown in the schematic diagrams of FIGS. 8 and 9, the linear antenna 8 having an electrical length of approximately 1/4 of the resonance wavelength is placed above the distal end of the linear antenna 8 approximately 1/4 of the resonance wavelength. The coiled element 70 having the required number of turns and having an electrical length of 4 is covered and fixed by the element cover 71 in a separated state, and when the linear antenna 8 is extended, power is supplied substantially at the lower end of the linear antenna 8. Only the linear antenna 8 works,
When the linear antenna 8 is stored in the housing 1,
The connection between the linear antenna 8 and the power supply unit 90 is cut off, and at the same time, the lower end of the coil-shaped element 70 is connected to the power supply unit 90 and supplied with power, so that substantially only the coil-shaped element 70 functions as a shortened antenna. Is what it is.
Incidentally, reference numeral 51 in the figure denotes a matching circuit.

[0005]

In the first conventional example, in order to exchange electric signals, a loading coil 70 built in the shortened antenna 7 is provided at the tip of the linear antenna 8 inside the antenna. A machine that requires a processing step for direct mechanical connection at the connection portion 80 and that allows the lower end portion of the linear antenna 8 and the metal portion 81 to contact the contact fitting 91 between the antenna and the wireless device body In the second conventional example, a linear antenna 8 must be provided between the antenna and the radio body.
When the linear antenna 8 is extended, power is supplied at the lower end portion of the linear antenna 8, and when the linear antenna 8 is stored,
A complicated mechanical configuration such that the lower end of the coil-shaped element 70 is connected to the power supply unit 90 at the same time as the connection with the power supply unit 90 is cut off, and the structure is complicated and the cost is increased accordingly. The metal part 81 of the mechanical connection part 80 is separated from the element cover 71 and the contact fitting 91 of the power supply part 90.
Is exposed from the housing 1 and has a poor appearance, and a frequency change occurs when a human body approaches or comes into contact with the exposed portion, which has a serious effect on the wireless device.

In the first conventional example, the total length of the linear antenna 8 and the coil element 70 is the sum thereof, and in the second conventional example, the linear antenna 8 and the coil element 70 are separated and fixed. Therefore, the total length is larger than the sum, and it is impossible to reduce these dimensions.

According to the present invention, there is provided a processing step for mechanically connecting the distal end of a linear antenna and a loading coil for exchanging an electric signal and for mechanically connecting the linear antenna to a radio unit as described above. Unnecessary, simplifying the structure,
It facilitates manufacturing, lowers costs, and eliminates the exposed portion to simplify its appearance, and reduces the effect of the human body on close contact with the exposed portion to affect the frequency change. It is an object of the present invention to make effective use of the space in the wireless device.

[0008]

In order to solve the above-mentioned problems, an antenna for a radio device according to the present invention comprises a linear antenna mounted in a housing so as to be able to be taken in and out, and a longitudinally extending axis of the linear antenna. a coil-shaped element of the required number of turns around, the whole being inserted into the interior of the linear antenna and the tip portion the coiled element linear antenna as a coiled element is a capacitive coupling state A covered antenna whose outer periphery is connected to the feeder and
Made a part of a ring, wherein the wire antenna is moved, the wire antenna to the linear antenna and coupling means you the capacitive coupling state and the power supply unit to set <br/> when all housed in a housing only, and the linear antenna when all housed in a housing
A grounding means for connecting the linear antenna is provided, and a part of the linear antenna is brought into contact with a ground point.

[0009] The linear antenna section may be composed of a superelastic metal and a covering material of the superelastic metal. Further, the linear antenna section may have a multi-stage rod antenna structure.

[0010]

According to the structure of the present invention, the tip of the linear antenna is inserted into the coil element so that the linear antenna and the coil element are in a capacitively coupled state. Since the linear antenna and the feeding unit are provided with a coupling unit in which the linear antenna and the feeding unit are in a capacitively coupled state when all of them are stored in the linear antenna and the coil-like element, and between the coil-like element and the feeding unit,
High-frequency signals can be exchanged without forming a mechanical connection part for transmitting and receiving electric signals. Since the whole of the linear antenna and the coil-shaped element is covered and the element is not exposed, there is no influence on the frequency change and the like due to the close contact of the human body. Since the grounding means is provided so that a part of the linear antenna comes into contact with the ground point when the linear antenna is entirely housed in the housing, when the linear antenna is entirely housed in the housing, the antenna has only a coil-shaped element. In contrast, when the linear antenna is pulled out, the antenna operates as an antenna having an electrical length that is the sum of the electrical lengths of the linear antenna and the coil element.

Further, if the element of the linear antenna portion is made of a superelastic metal, the flexibility becomes extremely good. In the above-mentioned first and second conventional examples, the mechanical connection to the coil-shaped element and other parts is performed.
If superelastic metal is used, connection processing will be extremely difficult and the cost will be extremely high, but according to the capacitive coupling of the present invention,
Connection to coiled elements and other parts is also easy.

If the linear antenna section has a multi-stage rod antenna structure, the rod antenna can be folded small, so that the overall size of the portable wireless device can be further reduced.

[0013]

Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

FIG. 1 is a partial cross-sectional view of an embodiment of the present invention when an antenna is extended, FIG. 2 is a schematic view of FIG. 1, FIG. 3 is a partial cross-sectional view of the same embodiment when the antenna is housed, and FIG. FIG. 6 is a schematic diagram illustrating an example of dimensions of each part of the antenna of the embodiment of FIG. 5.

This embodiment relates to an antenna system for a portable telephone using a 900 MHz band, and has a resonance wavelength of λ / 2.
Antenna part 2 having an electrical length of 167 mm
The whip antenna section 3 and the shortened whip antenna section 3 are coaxially provided with a required number of turns of the shortened whip antenna section 3 having an electrical length (25 mm) of the resonance wavelength λ / 4 at the tip of the whip antenna section so as to exhibit capacitive coupling C1. , Whip antenna part 2
Of the element 20 is inserted into the loading coil 30 of the shortened whip antenna unit 3, the loading coil 30 is covered with the coil case 4, and the element 20 is covered with the element cover 40.

The loading coil 30 is formed by winding a phosphor bronze wire, and the element 20 is formed of a superelastic alloy.

The whip antenna section 2 is mounted so as to be able to be inserted into and removed from the housing 1 of the portable telephone. When the whip antenna section 2 is extended, the element 20 inside the whip antenna section 2 is connected to a ring 10 provided inside the access port.
Is directly connected to the matching circuit 51 on the substrate 5 via the power supply unit 50 by direct power supply. When the whip antenna unit 2 is completely housed in the housing 1, the whip antenna unit 2 is attached to the housing 1 by a metal fitting 21 having a cutout 22 on a side surface attached to the lower end of the whip antenna unit 2.
It is configured to be connected via a grounding section 60 to a grounding metal fitting 6 provided at a lower portion in the inside.

In the present invention, the tip of the whip antenna 2 is inserted into the shortened whip antenna 3, so that the tip of the whip antenna 2 can be shortened regardless of the expansion or contraction of the whip antenna 2. The whip antenna unit 3 is capacitively coupled (C1) at a high frequency. Therefore, when the antenna of the present invention is in the extended state, the lower end of the whip antenna unit 2 is at the position of the ring 10 and the capacitive coupling C2 is performed with the feed unit 50. As a result, the present antenna and the feed unit 50 And high frequency signals can be exchanged without forming a mechanical connection for transmitting and receiving electric signals. That is, when the present antenna is in the extended state, the electric length of the entire antenna becomes 3λ / 4 which is the sum of the electric length of λ / 2 of the whip antenna unit 2 and λ / 4 of the shortened whip antenna unit 3, and A characteristic almost equivalent to that of an antenna having an electrical length of λ / 2, which is optimal as an antenna, is obtained.

When the whip antenna section 2 is completely housed in the housing 1, the whip antenna section 2 is provided at a lower portion in the housing 1 by a metal fitting 21 having a notch 22 on a side surface attached to a lower end thereof. A grounding part 60 is attached to the grounding metal 6.
And the upper end of the whip antenna unit 2 is located at the position of the ring 10 connected to the feeding unit 50, and the shortened whip antenna unit 3 performing capacitive coupling C1 with the upper end of the whip antenna unit 2 Performs capacitive coupling C2 with the power supply unit 50 . As a result, the antenna is between only the short whip antenna section 3 of the power feeding unit 50, it is possible to exchange the tooth frequency signal to form a mechanical connection portion for electrical signal exchange. That is , when the present antenna system is stored, the effective electrical length of the entire antenna is only λ / 4 of the shortened whip antenna unit 3. FIG. 4 shows this state. In this case, since the impedance Z of the whip antenna unit 2 in the housed state is made infinite and the power supply to the whip antenna unit 2 is completely cut off, the whip antenna unit 2 does not exist. They are equal.

In this embodiment, the loading coil 30 is covered by the coil case 4, the element 2 is covered by the element cover 40, the element 20 is not exposed, and the capacitive coupling portions C1 and C2 are also removed. It has a configuration in which various connection fittings are not exposed as in the conventional example. This eliminates the need for a processing step for mechanically connecting the upper end of the whip antenna unit 2 and the shortened whip antenna unit 3 and exchanging the whip antenna unit 2 with the wireless device body for exchanging electric signals. Because of the simplicity, manufacturing is easy, the cost of manufacturing is low, the exposed part is eliminated and the appearance is quite simple, the influence on the frequency change etc. due to close contact of the human body is reduced, The space within the portable telephone can be effectively used by the capacity coupling portion C1.

In this embodiment, since the element 20 of the whip antenna 2 is formed of a Ni-Ti alloy, a so-called superelastic metal, the flexibility of the whip antenna 2 is extremely good. Due to this good flexibility, there is no fear of breaking or bending without being very careful in handling the antenna. Further, the conventional whip antenna section 2 has a loading coil 30.
However, due to the mechanical connection, the use of super-elastic metal makes connection processing extremely difficult and the cost becomes extremely high. I was able to do it.

If the whip antenna section 2 (element 20) adopts a multi-rod antenna structure, the overall configuration can be reduced in size.

It should be noted that the present invention is not limited to the above-described embodiment, and a configuration in which the shortened whip antenna section 3 can be at least partially housed inside the housing 1 can be adopted.

[0024]

As described above, in order to solve the above-mentioned problems, the present invention provides a linear antenna which can be inserted into and removed from a housing, and a coil having a required number of turns about the extension axis of the linear antenna in the front end direction. Element, the tip of the linear antenna is inserted inside the coil-shaped element so that the linear antenna and the coil-shaped element are in a capacitively coupled state, and the whole is covered. At the time of extension, the linear antenna is electrically connected to the power supply unit by direct power supply, and in a state where the linear antenna is completely housed in the housing, there is a coupling means that the linear antenna and the power supply unit are in a capacitive coupling state. The radio antenna is provided with a grounding means provided with a part of the linear antenna in contact with a ground point. Further, the linear antenna portion has a structure made of a superelastic metal and a covering material of the superelastic metal. The linear antenna section has a multi-stage rod antenna structure.

As a result, a processing step for mechanically connecting the tip of the linear antenna and the loading coil for exchanging high-frequency signals becomes unnecessary, and the loading coil in a state in which the linear antenna is completely housed is not required. There is no need for a processing step for mechanically connecting the power supply unit, and the structure is simple, manufacturing is easy and low cost, there is no exposed metal part, the appearance is simple, and the effect of frequency changes due to close contact with the human body Is eliminated, and at the same time, it is possible to effectively use the limited space in the wireless device.

Further, when the element of the linear antenna portion is made of a superelastic metal, the flexibility is extremely good, and there is no fear that the antenna will be bent or bent without being so careful in handling the antenna. The problem in using a superelastic metal is solved.

In the case where the linear antenna has a multi-stage rod antenna structure, the rod antenna itself can be folded small, so that the overall size of the portable wireless device can be further reduced.

[0028]

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of one embodiment of the present invention at the time of extension.

FIG. 2 is a schematic diagram of FIG.

FIG. 3 is a partial cross-sectional view at the time of reduction in the embodiment.

FIG. 4 is a schematic diagram of FIG.

FIG. 5 is a schematic diagram showing dimensions of each part of the antenna at the time of reduction according to the embodiment.

FIG. 6 is a diagram illustrating a first conventional example at the time of extension.

FIG. 7 is a diagram illustrating a first conventional example at the time of reduction.

FIG. 8 is a diagram for explaining a second conventional example at the time of extension.

FIG. 9 is a diagram for explaining a second conventional example at the time of reduction.

[Explanation of symbols]

 1 housing 10 rings

Continuation of the front page (72) Koji Umeda 300-18, Tohara, Motohara, Kamikawa-cho, Kodama-gun, Saitama Prefecture Inside of Saitama NEC Co., Ltd. (72) Takao Ono 3-50-1, Kamiishihara, Chofu-shi, Tokyo (56) References JP-A-4-58603 (JP, A) EP 467822 (EP, A2) WO 92/16980 (WO, A1) (58) Fields investigated (Int. Cl. ^7, DB name) H01Q 1/24 H01Q 9/36

Claims (3)

(57) [Claims] 1. A linear antenna, which is attached to a housing so as to be able to be taken in and out, and a coil-like element having a required number of turns substantially centered on a longitudinal extension axis of the linear antenna. When the element and the capacitive coupling state
Comprising as the tip portion of the linear antenna is inserted inside the coiled element antenna that whole is covered
And the outer periphery is connected to the feeder and the linear antenna moves inside.
It made that the ring, the coupling means shall be the capacitive coupling state and the linear antenna and the power supply portion when the total housing the wire antenna in the housing is provided, and housing the wire antenna
A connection that connects to the linear antenna when fully stored inside the body
Has a ground unit, radio antenna that characterized thereby partially the ground point contact <br/> touch of the linear antenna. 2. The linear antenna according to claim 1, wherein the linear antenna comprises a superelastic metal and a covering material of the superelastic metal.
An antenna for a radio as described. 3. The radio antenna according to claim 1, wherein the linear antenna has a multi-rod antenna.