JPH06204908A - Radio equipment antenna - Google Patents

Abstract

PURPOSE:To entirely miniaturize a radio equipment antenna and to secure the radiation characteristic equivalent to a dipole antenna by setting two plane antennas at the points near the edge part of a radio equipment to ensure a function equivalent to a 1/4-wavelength antenna and by constructing an equivalent 1/2-wavelength antenna for both transmission and reception. CONSTITUTION:The plane antennas 2 and 3 which function equivalently to a 1/4-wavelength antenna are set close to each other and electrically connected to a casing 1 where the short circuit elements 4 and 5 are set at ground potentials at their positions close to each other. Thus both antennas 2 and 3 can function as a whole equivalently to a 1/2-wavelength antenna for both transmission and reception. Therefore the antenna radiation characteristic substantially equal to that of a dipole antenna of 1/2 wavelength is secured. Then the satisfactory radiation characteristic is obtained comparing in case where a single antenna functioning equivalently to the 1/4-wavelength antenna is used. That is, the electric field induced at the casing 1 is reduced and the antenna radiation characteristic is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio antenna mounted on a housing of a radio, such as a portable radio,
It is used for MCA radios, radios used for commercial radios, mobile phones, and the like.

[0002]

2. Description of the Related Art A dipole antenna is known as an antenna for a portable radio device. Since this dipole antenna requires a half wavelength of a carrier wave,
This has been an obstacle to the demand for smaller antennas.

Recently, in order to meet the demand for miniaturization of the antenna, it has been considered to use a whip antenna or a microstrip antenna equivalently functioning as a 1/4 wavelength antenna.

However, in a whip antenna or a microstrip antenna equivalently functioning as a quarter-wave antenna, since the housing of the radio is usually made of metal, the radiation of the antenna is caused by an electric field induced in the metal housing. There is a problem that the characteristics are likely to deteriorate, and that a human holds the housing when using the radio, and the radiation characteristics of the antenna deteriorate due to the influence of the human.

Therefore, in order to solve such a problem, the following techniques have been conventionally proposed. (1) A whip antenna equivalently functioning as a 1/4 wavelength antenna is provided on the upper part of the metal housing of the radio, and an odd multiple of 1/4 wavelength is provided from the connection end of the whip antenna with the metal housing. A technique in which a strip-shaped metal body is wound around a position separated by a distance while being insulated from the metal housing (Japanese Patent Laid-Open No. 2-54631). (2) A technology in which a handset is provided on one surface of a metal housing of a wireless device, an inverted F-shaped antenna is attached to the other surface, and the inverted F-shaped antenna is grounded at the upper end of the metal housing (Japanese Patent Publication No. 63-
8655). (3) A technology in which a microstrip antenna and a whip antenna are provided in a metal housing of a radio device, and the microstrip antenna is used only for reception, and the whip antenna is used for transmission and reception, and has a diversity function at the time of reception. (JP-A-62-49729). (4) A technique in which an antenna unit is rotatably provided on a telephone body, a whip antenna and an inverted F-shaped antenna are housed in the antenna unit, and the antenna unit is erected when used (Japanese Patent Laid-Open No. 175826/1993). Gazette).

[0006]

However, the above conventional techniques have the following problems. (1) In the technique disclosed in Japanese Patent Application Laid-Open No. 2-54631, a metal body for improving radiation characteristics is placed at a position separated from the connection end of the whip antenna with the metal housing by an odd multiple of 1/4 wavelength. Since it needs to be provided, there is a problem that the mounting space is limited. In addition, since the human body holds the metal housing by hand when using the wireless device, the metal body for improving the radiation characteristic is also covered by the human hand, and as a result, the radiation characteristic is inevitably deteriorated. There are problems that arise. (2) In the technique disclosed in Japanese Patent Publication No. 63-8655, since the inverted F-shaped antenna is attached only to the side surface of the metal casing which stands up when used, the main radiation direction of the inverted F-shaped antenna is horizontal. I did not go inward and leaned downward,
There is a problem that the radiation characteristic during transmission is deteriorated. (3) In the technique of Japanese Patent Laid-Open No. 62-49729, a microstrip antenna and a whip antenna are used, but this is merely for adding a diversity function at the time of reception, and only a whip antenna is used at the time of transmission. Since it is not used, there is a problem that the radiation characteristic at the time of transmission deteriorates. (4) In the technique disclosed in JP-A-3-175826, a whip antenna and an inverted F-shaped antenna are used, but like the case of (3) above, this simply adds a diversity function at the time of reception. However, there is a problem that the radiation characteristic at the time of transmission is deteriorated.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a radio antenna which is small in size and capable of preventing deterioration of radiation characteristics. is there.

[0008]

According to the radio antenna of the present invention, two planar type antennas equivalently functioning as 1/4 wavelength antennas are arranged close to the end of the radio casing. It is characterized in that a half-wave antenna equivalent to both transmission and reception is configured.

Further, the radio antenna of the present invention comprises a rod-shaped antenna equivalently functioning as a quarter-wave antenna and a planar antenna equivalently functioning as a quarter-wave antenna, and a casing of the radio. It is characterized in that a half-wave antenna equivalent to both transmitting and receiving is arranged close to the end of the antenna.

[0010]

In the present invention, since two antennas equivalently functioning as 1/4 wavelength antennas are used to equivalently configure a 1/2 wavelength antenna, the radiation characteristic is less deteriorated.
So to speak, the same performance as a dipole antenna can be obtained.

Further, since the two antennas are concentratedly provided at the end of the casing of the radio, the antenna is not covered with human hands even when the radio is used, and the deterioration of radiation characteristics is reduced. .

Further, since at least one of the antennas is a plane type antenna, it can be sufficiently miniaturized as compared with the case of using a normal dipole antenna.

[0013]

EXAMPLES Examples of the present invention will be described below. Embodiment 1 This embodiment corresponds to claim 1, and as shown in FIG. 1, the planar antennas 2 and 3 are provided on the side surface and the upper surface of the corner portion of the housing 1 made of metal of the radio device, respectively. It is installed close to each other. These planar antennas 2 and 3 are
Each of them independently functions as a quarter-wave antenna equivalently.

On the other hand, the planar antenna 2 has a function as a main radiating element, and is, for example, a microstrip antenna having an inverted F-shaped antenna structure.

The other planar antenna 3 has a function as a sub-radiating element, and is, for example, a microstrip antenna having an inverted L-shaped antenna structure.

Here, the microstrip antenna means an antenna made of a strip (strip) of thin (micro) conductors, but normally, a conductor plate for grounding the strip of thin conductors forming a microstrip line. A thin insulator 22 is sandwiched between 21 and 21, and has a large electrical length (wavelength becomes short). However, the insulator is not always necessary when configuring the planar antenna of the present invention. Further, the planar antenna 3 may have an S-shaped or key-shaped bent shape (shape having an S-shaped curve as a key shape) when viewed from a position facing the planar antenna 3 to increase its length.

Short-circuit elements 4 and 5 for grounding are provided at positions close to each other of the planar antennas 2 and 3, respectively.
Are provided, and these short-circuit elements 4 and 5 are electrically connected to the housing 1 which is set to the ground potential. The positions of these short-circuit elements 4 and 5 should be as close as possible to one another, so that
The function as a wavelength dipole antenna can be sufficiently enhanced. Furthermore, the connection positions of the short-circuit elements 4 and 5 and the housing 1 may be the same.

Reference numeral 6 is a power supply line, which is used when the radio is used.
A current is supplied to the planar antenna 2 from the feeder line 6.

According to this embodiment, the planar antennas 2 and 3 equivalently functioning as the quarter-wave antenna are arranged close to each other, and the short-circuit elements 4 and 5 are set to the ground potential at positions close to each other. Since it is electrically connected to the housing 1, it functions as an equivalent 1 / 2-wavelength antenna for both transmission and reception as a whole. Therefore, the radiation characteristic of the antenna is almost the same as that of the dipole antenna of 1/2 wavelength, and the radiation characteristic is excellent as compared with the case where only the antenna equivalently functioning as the 1/4 wavelength antenna is used alone. can get. That is, the fed current concentrates on the planar antennas 2 and 3, and the current flowing in the housing 1 is suppressed to a small level, so that the electric field induced in the housing 1 is reduced and the radiation characteristics of the antenna are reduced. Be improved.

Since the planar antennas 2 and 3 are both planar and small in size, the antenna composed of both of them has a small structure as a whole.

Further, since the planar antennas 2 and 3 are concentratedly provided on the upper part of the housing 1, the planar antennas 2 and 3 are not covered with human hands when the radio is used, Radiation characteristics due to humans are unlikely to deteriorate.

FIG. 2 shows the radiation characteristic of the antenna of this embodiment, and FIG. 3 shows the radiation characteristic of the antenna when the planar antenna 3 is not provided in FIG. Note that FIG.
And in FIG. 3, the solid line indicates the radiation characteristic in the horizontal plane,
The dotted line shows the radiation characteristic in the vertical plane. As can be seen from FIGS. 2 and 3, according to the antenna of this embodiment, the gain in the horizontal plane is improved by 2 to 10 dB.

FIG. 4 shows the frequency characteristic of the antenna of this embodiment, and FIG. 5 shows the frequency characteristic of the antenna when the planar antenna 3 is not provided in FIG. As can be seen from FIGS. 4 and 5, the frequency band at 10 dB (indicated by A in FIGS. 4 and 5) is about 3.7 times wider with the antenna of this embodiment. .

In this embodiment, the short-circuit element 4 of one of the planar antennas 2 is to be connected to the housing 1 which is set to the ground potential in order to achieve matching as an inverted F-shaped antenna. If it is not necessary to connect the short-circuit element 4 to the housing 1 when matching is to be performed inside the housing 1, it is not necessary to connect the short-circuit element 4 to the housing 1.

The planar antenna 3 may be provided not on the upper surface of the housing 1 but on the side surface, and the same effect can be obtained in this case as well. The planar antenna 2 may have a structure in which a strip-shaped antenna is wound around the housing 1. Example 2 This example corresponds to claim 2. As shown in FIG. 6, a quarter wavelength antenna is equivalently provided on the upper surface of the corner portion of the housing 1 made of metal of the wireless device. The rod-shaped antenna 7 functioning as is provided so as to be insulated from the housing 1. As the rod-shaped antenna 7, for example, a whip antenna equivalently functioning as a 1/4 wavelength antenna can be used.

On the other hand, at a position on the side surface of the corner portion of the housing 1 and near the connecting portion between the rod-shaped antenna 7 and the housing 1, the planar antenna 8 equivalently functions as a quarter-wave antenna. Is provided. The planar antenna 8 is, for example, a microstrip antenna and has an inverted F-shaped antenna structure.

The planar antenna 8 is provided with a short-circuit element 9, and the short-circuit element 9 includes the rod-shaped antenna 7 and the housing 1.
It is electrically connected to the housing 1 at earth potential at a position close to the connection portion with.

According to this embodiment, the rod antenna 7 equivalently functions as a 1/4 wavelength antenna and 1 / equivalently.
Since the planar antenna 8 functioning as a four-wavelength antenna is arranged close to the end portion of the housing 1, a half-wave antenna equivalent to both transmission and reception is constructed. Therefore, the radiation characteristic of the antenna is almost the same as that of the dipole antenna of 1/2 wavelength, and the radiation characteristic is excellent as compared with the case where only the antenna equivalently functioning as the 1/4 wavelength antenna is used alone. can get. That is, the fed current concentrates on the rod-shaped antenna 7 and the planar antenna 8 and the current flowing through the housing 1 is suppressed to a small level.
The electric field induced in the housing 1 is reduced, and the radiation characteristic of the antenna is improved.

Further, since the planar antenna 8 is provided on the upper portion of the housing 1, the planar antenna 8 is not covered with human hands when the radio is used, and therefore the radiation characteristics caused by humans are eliminated. It is possible to prevent deterioration of

Further, since the planar antenna 8 is small, it can be sufficiently miniaturized as compared with the case where a dipole antenna is used.

FIG. 7 shows the radiation characteristic of the antenna of this embodiment, and FIG. 8 shows the radiation characteristic of the antenna when the planar antenna 8 is not provided in FIG. It is understood from FIGS. 7 and 8 that the antenna of this example improves the gain in the horizontal plane by 5 dB.

The planar antenna 8 may have a structure in which a strip-shaped antenna is wound around the top of the housing 1.

[0033]

(1) According to the invention of claim 1, two planar antennas equivalently functioning as quarter-wave antennas are arranged close to the end of the casing of the wireless device, and transmission is performed. Since an equivalent 1/2 wavelength antenna that doubles as a receiver is configured,
It is possible to reduce the size of the entire antenna, obtain the radiation characteristic equivalent to that of the dipole antenna, and prevent the radiation characteristic from being deteriorated due to human beings even during use. (2) According to the invention of claim 2, a rod-shaped antenna equivalently functioning as a quarter-wave antenna and a planar antenna equivalently functioning as a quarter-wave antenna are provided at an end of a casing of a radio device. Since the half-wave antenna equivalent to both transmitting and receiving is arranged close to the section, the entire antenna can be downsized, and radiation characteristics equivalent to those of the dipole antenna can be obtained. Even during use, it is possible to prevent deterioration of the radiation characteristics due to human beings.

[Brief description of drawings]

FIG. 1 is a perspective view of a wireless device antenna according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a radiation characteristic of the antenna of the first embodiment.

FIG. 3 is a diagram showing radiation characteristics of the antenna in the case where the planar antenna 3 is not provided in the first embodiment.

FIG. 4 is a diagram showing frequency characteristics of the antenna of the first embodiment.

FIG. 5 is a diagram showing frequency characteristics of the antenna when the planar antenna 3 is not provided in the first embodiment.

FIG. 6 is a perspective view of a wireless device antenna according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a radiation characteristic of the antenna of the second embodiment.

FIG. 8 is a diagram showing radiation characteristics of the antenna in the case where the planar antenna 8 is not provided in the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 case 2 planar antenna 3 planar antenna 4 short-circuit element 5 short-circuit element 6 feed line 7 rod-type antenna 8 planar antenna 9 short-circuit element

Claims (2)

[Claims] 1. An equivalently ½ wavelength antenna for transmitting and receiving, wherein two planar type antennas equivalently functioning as ¼ wavelength antennas are arranged close to an end of a casing of a radio device. An antenna for a wireless device, which is configured by 2. A rod-shaped antenna equivalently functioning as a quarter-wave antenna and a planar antenna equivalently functioning as a quarter-wave antenna are arranged close to the end of the casing of the radio device, An antenna for a wireless device, characterized in that a half-wave antenna equivalent to both transmission and reception is configured.