JPH09162621A - Antenna structure for portable radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna structure for a portable radio equipment which does not receive an electromagnetic noise generated by a control circuit section in a case and obtains excellent speech quality even when the radio equipment is located in a weak electric field strength area at a weak electric field strength of a communication radio wave or while its antenna is set in a contained state. SOLUTION: A base end of a rod antenna 20 is covered by an insulating straw member 29 and the antenna 20 is housed in a case 10, the rod antenna 20 is fixed to an upper part of the case 10 by mount metal fittings 22, a tip of the rod antenna 20 is projected to the outside of the case 10 in an extension enable way, an antenna contact terminal 23 is connected to the mount metal fittings 22, which is connected to a communication circuit section housed in a shield case 19 via the terminal 23. Then a part of the rod antenna 20 toward its base end from the mount metal fittings 22 and in the vicinity of the mount metal fittings 22 is free-fit to a shield tube 30 whose outer circumference has a flat part, and the flat part of the shield tube 30 is in face contact with the shield case to make electric conduction between them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna structure for a portable wireless device, and more particularly to an antenna structure which eliminates the influence of electromagnetic noise generated by an internal control circuit.

[0002]

2. Description of the Related Art Generally, a portable wireless device such as a mobile phone has a communication circuit section and a control circuit section housed in a main body case.
The rod antenna connected to the communication circuit unit is configured such that the distal end portion thereof is projected outside the main body case and can be extended.
As is well known, the communication circuit section is housed in a shield case made of a conductive metal or the like to be electromagnetically shielded, and the rod antenna has a power supply section in the main body case. Connected with.

[0003]

However, in the portable wireless device, the impedance of the power feeding portion of the rod antenna is high, it is easy to receive the electromagnetic wave generated by the communication circuit portion in the case, and communication noise increases. It was a cause of deterioration of call quality. In particular, this tendency is remarkable when performing communication in a weak electric field region where the electric field strength of communication radio waves is weak, or when performing communication by accommodating the rod antenna in the case main body, and its solution has been desired. The present invention has been made in view of the above problems, and an object of the present invention is to provide an antenna structure of a portable wireless device that can prevent deterioration of communication quality due to electromagnetic waves generated by a control circuit unit.

[0004]

In order to achieve the above-mentioned object, a portable wireless device according to the present invention is provided with an antenna by projecting a front end portion of the main body case to the outside, and at the same time, a base from a power feeding portion of the antenna. At least the portion near the power supply portion on the end side is loosely inserted into a shield tube made of a conductive material,
The shield tube was brought into electrical contact with a shield case that covers the wireless circuit section and brought into contact therewith.

Examples of the portable wireless device which is the object of the present invention include a portable telephone such as PHS, a transceiver and the like. This portable wireless device can be applied to a device that uses a rod antenna for transmission and reception, and a device that has a built-in antenna in addition to the rod antenna and adopts a diversity system, regardless of the method of transmitting and receiving the rod antenna. Applied.

The shield tube is in the shape of a pipe into which the rod antenna can be loosely inserted, and is formed by forming a thin film of conductive metal on the outer or inner surface of the pipe such as conductive metal or resin. The conductive portion is electrically connected to the shield case and the ground. In a desirable mode, the shield tube has a flat surface on the outer surface of which the conductive portion is exposed, and the flat surface is provided so as to contact the shield case. The shield case is made of a conductive metal or a resin or the like on which a film of a conductive metal is formed.

In the portable wireless device antenna structure according to the present invention, the high impedance portion of the antenna, that is,
The vicinity of the power feeding portion is covered with a shield tube electrically connected to the shield case, and electromagnetically shielded. Therefore, the electromagnetic noise generated by the control circuit section in the main body case is not received, and good communication can be performed even in the state where the rod antenna is housed and in the weak electric field area.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 show an antenna structure of a portable wireless device according to an embodiment of the present invention,
FIG. 1 is a schematic view of a mobile phone which is a mobile wireless device, FIG. 2 is a front view of essential parts, and FIG. 3 is a plan view of main parts.

As shown in FIG. 1, a case 10 is constructed by assembling front and back case halves of a mobile phone. The case 10 has a well-known receiver 11, a liquid crystal display 12, various function keys 13, and numerals on the surface. A key 14 and a microphone 15 are provided, and although not shown, a CPU is internally provided.
A control circuit unit having the above, a communication circuit unit having a transmitting / receiving circuit, the rod antenna 20, a built-in antenna, a battery, and the like are housed. As is well known, the communication circuit unit is housed in a shield case 19 (see FIG. 2) made of a conductive metal or a resin on which a conductive metal is deposited to form a conductive thin film.

As shown in FIG. 2, the rod antenna 20 has a distal end portion 20a projecting outside the case 10 so that it can expand and contract, and a proximal end portion 2 having a diameter smaller than that of the distal end portion 20a.
0b is covered with a straw member 29 made of an insulating material and housed in the case 10. This rod antenna 20
Is a fitting 2 made of a conductive metal at the upper end of the base end side portion 20b.
It is fixed to the upper part in the case 10 by 2. An antenna matching board 24 is connected to the mounting bracket 22 by an antenna contact terminal 23, and the rod antenna 20 is connected to the above-mentioned communication circuit section via the antenna matching board 24.
The mounting metal fitting 22 corresponds to a power feeding section.

Further, in the rod antenna 20, the shield tube 30 is loosely inserted in the vicinity of the mounting bracket 22 on the base end side of the mounting bracket 22. As shown in detail in FIG. 3, the shield tube 30 is formed by molding a conductive plate into a cylindrical shape having a substantially semicircular cross section, and a flat portion 31 is formed on the outer circumference. The shield tube 30 is attached to the case 1 by a fitting not shown.
0 is fixed inside the shield case 19 and the flat portion 31 is
It comes into contact with and becomes electrically conductive.

The length of the above-mentioned shield tube 30 is
The length of the rod antenna 20 in the vicinity of the mounting bracket 22, that is, the portion where the impedance of the rod antenna 20 has a high impedance is loosely inserted.
It is also possible to set the length so that the entire range from the mounting bracket 22 to the base end can be inserted. Further, the shield tube 30 does not necessarily have to be made of a conductive metal, but a conductive film is formed on the outer surface or the inner surface of an insulating pipe such as a resin, and this film is used for a shield case or an earth by using a conductor or the like. It is also possible to connect to terminals.

In the portable device of this embodiment, the seal tube 30 in which the portion near the mounting member 22 of the rod antenna 20, that is, the portion with a high impedance (hereinafter referred to as the high impedance portion) is electrically connected to the shield case 19 is provided. Thus, the high impedance portion does not receive the electromagnetic wave emitted by the control circuit portion or the like. Therefore, good communication can be performed without noise even in a weak electric field area where the electric field strength of the communication radio wave is weak, and good communication can be performed without noise even if communication is performed with the rod antenna 20 housed.

A flat portion 31 is formed on the shield tube 30, and the flat portion 31 is brought into surface contact with the shield case 19 to electrically connect the shield tube 30 and the shield case 19. It can be obtained reliably and the structure can be simplified because no wire or the like is required.

[0015]

As described above, according to the antenna structure of the portable communication device of the present invention, at least the vicinity of the feeding portion of the antenna is inserted into the conductive shield tube, and the shield tube accommodates the communication circuit section. Since it is in electrical contact with the shield case, it does not receive the electromagnetic noise generated by the control circuit section, and does not receive noise when communicating in a weak electric field area or when communicating with the antenna accommodated. The effect that a high telephone call can be performed is acquired. In particular, the present invention adopts a configuration in which a flat portion is formed on the shield tube and the flat portion is brought into contact with the shield case, so that electrical conduction between the shield tube and the shield case can be reliably obtained with a simple structure. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic view of a mobile phone which is a mobile wireless communication device according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a main part of the mobile phone.

FIG. 3 is a plan view of a shield tube which is a main component of the mobile phone.

[Explanation of symbols]

 10 Case Main Body 19 Shield Case 20 Rod Antenna 22 Mounting Bracket (Power Feeding Section) 23 Antenna Contact Terminal 24 Antenna Matching Substrate 29 Straw Member 30 Shield Tube 31 Flat Section

Claims (1)

[Claims] 1. A main body case is provided with an antenna by projecting a tip side portion thereof to the outside, and at least a portion near a power feeding portion on a base end side from a feeding portion of the antenna is loosely inserted into a shield tube made of a conductive material. An antenna structure for a portable wireless device, wherein the shield tube is electrically connected to a shield case that covers the wireless circuit section and brought into contact with the shield case.