JPH06260826A - wireless device - Google Patents

Abstract

(57) [Abstract] [Purpose] A wireless device that obtains good sensitivity in a call state by a spell top, and is particularly suitable for use in a wireless device that transmits weak power such as a cordless telephone, and is low cost and downsized. The purpose is to provide a wireless device that is easy to operate. According to the present invention, a dipole antenna is converted into unbalance by forming a spell top between an outer conductor 5b of a coaxial feed line 5 and a conductor 10 inside a housing 3 so as to break a loop of high frequency current. It is a wireless device configured in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile phone used for mobile communication, a portable radio transmitter, a receiver and the like.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 4-179302 has been proposed for the purpose of preventing characteristic deterioration due to leakage of an antenna current when a housing of a radio is touched. This technique is applied to the antenna 1 fed from the central conductor 5a of the coaxial feed line 5 as shown in FIG. 3 and a radio forming a dipole antenna by the ground wire 7 of the antenna 1, and a casing 12 covered with the conductor and its By forming a spell top with the conductor 13 that covers the upper surface to have a high impedance when viewed from the antenna 1 side, the antenna current is prevented from flowing to the housing.

[0003]

However, the structure in which the casing 12 is covered with the conductor and the upper surface of the casing 12 is covered with the conductor 13 for forming the spell top as in the above-mentioned conventional technique is not only costly. Contrary to the recent thinning of the housing, the housing becomes large and there is a mounting problem. In particular, in a device that transmits weak electric power such as a cordless telephone, since the weak electric power does not affect the internal circuit and the like, it is not necessary to cover the housing with a conductor, and it is possible to configure as in the above-mentioned conventional technique. The cost will increase and the equipment will become larger.

In order to solve the above-mentioned problems of the prior art, the present invention is a radio device that obtains good sensitivity in a call state by a spell top, and is particularly used for a radio device that transmits weak power such as a cordless telephone. It is an object of the present invention to provide a suitable low-cost radio device that can be easily downsized.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art, the present invention provides a dipole antenna, which is a balanced antenna, with a spertop inside the radio housing and with an outer conductor of its coaxial feed line. It is a wireless device in which conductors are arranged so as to be formed, and the formed spell top converts the conductor into unbalance to break the loop of high frequency current.

Specifically, an n / 4 wavelength antenna (n is an odd number) having a feeding point at the center conductor of the coaxial feed line and an n / 4 wavelength (n is an odd number) connected to the outer conductor of the coaxial feed line. ) Is provided, and a dipole antenna is configured by the n / 4 wavelength antenna and the ground wire, wherein the coaxial feed line is n / 4 from the feed point.
The outer conductor is grounded to the ground conductor of the circuit board at a position separated by a wavelength (n is an odd number) and is connected to one end of a conductor having a length of n / 4 wavelength (n is an odd number), and is connected to the coaxial feed line. A conductor having a length of n / 4 wavelength is arranged in parallel from the ground to the vicinity of the feeding point to form a spell top, and a radio housing portion covering the ground wire and the spell top forming portion is an insulator. It is a configured radio.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a wireless device showing an embodiment of the present invention, in which a quarter-wave antenna 1, a housing 3, a circuit board 4,
The wireless device is composed of the coaxial feeder 5, the ground wire 7 having a quarter wavelength, and the conductor 10 having a quarter wavelength.

The quarter-wave antenna 1 is connected to the center conductor 5a of the coaxial feeder 5 at a feeding point 2. A ground wire 7 having a length of ¼ wavelength is formed on the circuit board 4, and is connected to the outer conductor 5b of the coaxial power supply line 5 at a position 11 near the power supply point 2 to connect the antenna 1 and the ground wire 7 to each other. And constitute a dipole antenna. Further, the outer conductor 5b of the coaxial feed line 5 is connected to the ground conductor of the circuit board 4 for grounding at a ground point 6 which is a quarter wavelength away from the power feed point 2 and has a length of a quarter wavelength. It is connected to one end of the conductor 10. This conductor 1
0 is arranged in parallel with the coaxial feed line 5 from the grounding point 6 to the vicinity of the feed point 2 to form a spell top between the conductor 10 and the coaxial feed line 5.

FIG. 2 is a diagram showing the operating principle of FIG.
The impedance between the outer conductor 5b of the coaxial feed line 5 and the conductor 10 in the direction of the ground point 6 from the position 11 near the
Since 0 is grounded to the ground conductor of the circuit board 4 inside the housing 3 at the ground point 6, the impedance becomes high and a spur top is formed. Therefore, the outer conductor 5 of the coaxial feeder 5
High-frequency current in the direction of arrow 8 flowing outside b does not flow 1 /
It efficiently flows through the ground wire 7 having a length of 4 wavelengths, resulting in a current distribution 9. For this reason, the leakage current of the antenna does not flow in the ground conductor of the circuit board 4, and it is possible to prevent the characteristic deterioration when the housing 3 of the wireless device is touched, reduce unnecessary radiation due to the leakage of the antenna current, and improve the antenna efficiency. The performance of mobile phones, portable wireless transmitters and receivers can be improved.

Further, in order to improve the characteristics of the spell top and improve the current distribution 9, at least the conductor 10 and the ground wire 7 cannot be covered with a conductor. Therefore, it is necessary that at least the portion of the housing 3 which is in the vicinity of the ground wire 7 and the spertop formation portion and covers them is made of an insulating material. In particular, in the case of a wireless device with extremely low transmission power such as a cordless telephone, even if the housing 3 is made of an insulating material, the transmission power does not adversely affect the circuit inside the board. Good sensitivity can be obtained. Therefore, it is not necessary to further cover the housing 3 with a conductor, which facilitates miniaturization and contributes to a large cost reduction.

In the description of the embodiment of the present invention, it is natural that the antenna 1 and the ground wire 7 can be similarly applied even if the wavelength is n / 4 wavelength (n is an odd number), and the feeding point 2 and the ground point 6 are also applicable.
And the length of the conductor 10 are n / 4 wavelengths (n is an odd number)
You can Further, the antenna 1 and the ground wire 7 can be miniaturized by spirally winding them.

[0012]

INDUSTRIAL APPLICABILITY As described above, the present invention is particularly suitable for use in a wireless device such as a cordless telephone that transmits weak power, and a spertop is formed in the housing of the wireless device to generate a common-mode component of high frequency current. By breaking the loop, it is possible to reduce unnecessary radiation due to leakage of antenna current and prevent characteristic deterioration when touching the radio housing, so that good sensitivity can be obtained in the call state and the size of the housing can be easily reduced. Thus, it contributes to a large cost reduction.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a wireless device showing an embodiment of the present invention.

FIG. 2 is an operation principle diagram of FIG.

FIG. 3 is a cross-sectional view of a wireless device showing a conventional technique.

[Explanation of symbols]

 1 antenna 2 feeding point 3 housing 4 circuit board 5 coaxial feeding line 5a central conductor 5b outer conductor 6 grounding point 7 ground line 8 arrow 9 current distribution 10 n / 4 wavelength (n is an odd number) conductor

Claims (1)

[Claims] 1. An n having a feeding point at a central conductor of a coaxial feeding line.
/ 4 wavelength antenna (n is an odd number), and a ground wire having a length of n / 4 wavelength (n is an odd number) connected to an outer conductor of the coaxial power supply line, and the n / 4 wavelength antenna, A radio that comprises a dipole antenna with the ground line,
The coaxial feeder has a length of n / 4 wavelength (n is an odd number) and an outer conductor is grounded to a ground conductor of a circuit board at a position separated from the feeding point by n / 4 wavelengths (n is an odd number). The coaxial feed line and a conductor having a length of n / 4 wavelength are connected in parallel to one end of a conductor and are arranged in parallel from the ground to the vicinity of the feed point to form a spell top. A wireless device in which a wireless device housing portion that covers the forming portion is made of an insulating material.