JPH10270918A - Antenna for portable radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the antenna for portable radio equipment with high performance in which an excellent impedance characteristic is obtained by one matching circuit by making the impedance characteristic of the antenna in the extended state almost in matching with that in the contracted state. SOLUTION: In this antenna, a rod antenna element 1 having a characteristic of a half wavelength antenna and a cylindrical antenna element 2 having a characteristic of a <=1/4 wavelength antenna are coaxially placed, and the cylindrical antenna element 2 is fixed to a portable radio equipment main body and the rod antenna element 1 is extracted/contained from/to the portable radio equipment main body. In this case, in a extended state, base ends of the rod antenna element 1 and the cylindrical antenna element 2 are connected to allow only the rod antenna element 1 to act like the antenna, and in a contained state, the connection between both the elements is disconnected and only the cylindrical antenna element 2 acts like the antenna. Since the impedance characteristic of the cylindrical antenna element 2 is well in matching with the impedance characteristic of the rod antenna element 1, the impedance characteristic in the extended state of the antenna is almost made in matching with the impedance characteristic in the contracted state of the antenna.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna mounted on a portable radio such as a portable radio telephone, and more particularly, to an antenna provided with a rod-shaped antenna element and a cylindrical antenna element so that both antenna elements function exclusively. The present invention relates to a configured portable radio antenna.

[0002]

2. Description of the Related Art Portable wireless devices such as portable wireless telephones and transceivers are becoming smaller year by year, and there is a strong demand for smaller antennas mounted on portable wireless devices. For this reason, conventionally, this type of portable wireless device antenna is not used when the portable wireless device main body 31 is not used, as shown in FIG.
The antenna 32 can be housed inside, and at the time of use, FIG.
As shown in the figure, the antenna 32 can be pulled out from the portable wireless device main body 31. Various measures have been devised so that an incoming call can be detected even when the antenna is housed. For example, in the antenna disclosed in Japanese Patent Application Laid-Open No. 6-196912, a coil-shaped antenna element is connected to the tip of a rod-shaped antenna element that can be pulled out of and housed in a portable wireless device main body. A) A part of the antenna element protrudes from the main body of the portable wireless device so as to function as an antenna. In the antenna disclosed in Japanese Patent Application Laid-Open No. 7-508868, the rod-shaped antenna element and the helical antenna element are arranged coaxially with each other, and the helical antenna element is fixed to the main body of the portable wireless device. When used out of the radio unit, the base end of the rod-shaped antenna element and the base end of the helical antenna element are connected to each other, and only the rod-shaped antenna element functions as an antenna. When housed inside, the rod-shaped antenna element and the helical antenna element are disconnected from each other, so that only the helical antenna element functions as an antenna.

[0003]

However, in the antenna disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 6-196912,
The gain characteristic of the helical antenna element when housed is lower than the original characteristic value by about 0.5 dB to 1.0 dB.
This is because, since the rod-shaped antenna element and the helical antenna element are connected, the energy that should be originally supplied to the helical antenna element leaks to the rod-shaped antenna element housed in the portable wireless device main body. Further, in the antenna disclosed in Japanese Patent Application Laid-Open No. 7-508868, the helical antenna element and the rod-shaped antenna element are separated from each other at the time of storage, so that the gain characteristic of the helical antenna element can be obtained. Since the impedance characteristics of the elements are different, the impedance at the time of extension and the impedance at the time of storage do not match, and the voltage standing wave ratio (VSWR) is not good when matching is performed by one matching circuit.
Therefore, the problem to be solved by the present invention is to solve the above-mentioned drawbacks of the conventional technology, and to make the impedance characteristics at the time of extension and the impedance at the time of storage substantially coincide, thereby obtaining good impedance characteristics with one matching circuit. An object of the present invention is to provide a high-performance portable radio antenna.

[0004]

In order to solve the above-mentioned problems, a portable radio antenna according to the present invention has a rod-shaped antenna element having a half-wavelength antenna characteristic and an antenna characteristic having a quarter wavelength or less. And a cylindrical antenna element having an inner diameter larger than the outer diameter of the rod-shaped antenna element is arranged coaxially with each other, the cylindrical antenna element is fixed to the portable radio device main body, and the rod-shaped antenna element is connected to the portable radio device main body. An antenna configured so that it can be pulled out or stored from the main body of the portable wireless device when the rod-shaped antenna element is pulled out and used. Are connected to each other and only the rod-shaped antenna element functions as an antenna, and when the rod-shaped antenna element is stored in the portable wireless device main body. , Only the cylindrical antenna element connection is cut off and the rod-shaped antenna element and the cylindrical antenna element is characterized by being configured to function as an antenna. In the antenna for a portable wireless device of the present invention, when the rod-shaped antenna element is housed in the portable wireless device main body, the cylindrical antenna element and the rod-shaped antenna element are separated from each other. When the rod-shaped antenna element can be transmitted and received and the base end of the rod-shaped antenna element and the base end of the cylindrical antenna element are connected to each other when the rod-shaped antenna element is pulled out of the portable wireless device main body, the cylindrical antenna element is The function of the rod antenna element can be apparently stopped to transmit and receive radio waves with the inherent gain characteristics of the rod antenna element, and the impedance characteristics of the cylindrical antenna element and the rod antenna element match well compared to the helical antenna element. Therefore, the impedance at the time of extension and the impedance at the time of storage can be matched well.

[0005]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a partially broken front view showing an example of an embodiment of a portable wireless device antenna according to the present invention. FIG. 1 (a) shows a state of extension and FIG. 1 (b) shows a state of storage. Is shown. 2 is a perspective view showing a main part of the antenna for a portable wireless device shown in FIG. 1, wherein FIG. 2 (a) shows a state of extension and FIG. 2 (b) shows a state of storage. I have. In the drawing, reference numeral 1 denotes a rod-shaped antenna element having the characteristics of a half-wavelength antenna, 2 denotes a cylindrical antenna element having the characteristics of an antenna of 1/4 wavelength or less, and the rod-shaped antenna element 1 and the cylindrical antenna element 2 are coaxial with each other. It is arranged in a shape. The cylindrical antenna element 2 is fixed to an upper surface of a portable wireless device main body (not shown), and the rod-shaped antenna element 1 can be pulled out of the portable wireless device main body through the cylindrical antenna element 2 and stored therein. The rod-shaped antenna element 1 is formed of a nickel-titanium alloy or the like, and its peripheral surface is coated with a resin such as nylon. A resin cap 3 is attached to the distal end of the rod-shaped antenna element 1, and a connection fitting 4 for electrically connecting to the cylindrical antenna element 2 when extended is provided at the base end.
Is connected. The cylindrical antenna element 2 is made of brass or the like, and is substantially entirely molded with a resin, except for a feeder unit 5 integrally formed at the lower end thereof.
The power supply unit 5 is connected to a matching circuit 7 in the portable wireless device main body.

[0006] The feeding portion 5 is configured to extend the rod-shaped antenna element 1 when extended.
The connection fitting 4 at the base end of the rod-shaped antenna element 1 is fitted.
And the cylindrical antenna element 2 are electrically connected to each other, and are also holding portions for holding the rod-shaped antenna element 1 in an extended state or a stored state. An annular spring 6 made of beryllium steel is provided on the inner peripheral portion of the power supply portion 5. When extended, the connecting fitting 4 provided at the base end portion of the rod-shaped antenna element 1 is tightened and held. The middle portion of the cap 3 extending from the tip of the element 1 is fastened and held. The portable wireless device antenna of the present embodiment configured as described above has a state shown in FIGS. 1A and 2A, that is, in a state where the rod-shaped antenna element 1 is pulled out from the portable wireless device main body. The base end of the rod-shaped antenna element 1 and the base end of the cylindrical antenna element 2 are mutually connected. In this state, since the cylindrical antenna element 2 apparently becomes a part of the rod-shaped antenna element 1 and does not function itself, only the rod-shaped antenna element 1 functions as an antenna. Further, in the state shown in FIGS. 1B and 2B, that is, in a state where the rod-shaped antenna element 1 is stored in the portable wireless device main body, the cylindrical antenna element 2 and the rod-shaped antenna element 1 are electrically connected. Since they are separated, radio waves can be transmitted and received with the original gain characteristics of the cylindrical antenna element 2.

In addition, since the impedance characteristics of the cylindrical antenna element 2 match the impedance characteristics of the rod-shaped antenna element 1 better than that of the helical antenna element, the impedance when the antenna is extended and the impedance when the antenna is stored can be matched well. . Therefore, according to the antenna for a portable wireless device of the present embodiment, good impedance characteristics can be obtained with one matching circuit 7. Also, when communication is performed using two types of frequencies, a matching circuit can be easily designed.
One antenna can cope with a case where communication is performed by selectively switching two kinds of frequencies of Hz. For reference, the characteristics test results of the antenna of this embodiment are shown in FIG.
4 and FIG. 4 show a comparative example in which a cylindrical antenna element is replaced with a helical antenna element (Japanese Patent Application Laid-Open No. 7-5088).
FIG. 5 and FIG. 6 show the characteristic test results of the antenna disclosed in Japanese Unexamined Patent Publication No. 68).

FIGS. 3 and 5 are Smith charts showing characteristic test results at the time of extension, and FIGS. 4 and 6 are Smith charts showing characteristic test results at the time of storage. In the figure, four specific frequency points on the characteristic curve
△ 4. Δ1 to Δ4 are 890MH in order
The frequency points of z, 960 MHz, 1895 MHz, and 1918 MHz are shown. From the above test results, in the case of the antenna of the comparative example, the positions of specific frequency points # 1 to # 4 on the characteristic curve greatly change between when the antenna is expanded and when the antenna is housed, whereas in the antenna according to the present embodiment, when the antenna is expanded. It can be seen that there is almost no change in time and storage.
This means that the impedance of the antenna of the comparative example does not match the impedance at the time of extension and that of the antenna of the present embodiment, and the impedance of the antenna at the time of extension and the impedance at the time of accommodation are almost the same. The antenna for a portable wireless device according to the present invention can be used for a portable telephone such as a digital portable / automobile telephone (PDC) and a personal handyphone system (PHS).
It can be effectively applied to antennas of various portable wireless devices such as a transceiver and a portable computer with a built-in wireless communication device.

[0009]

As described above, according to the portable radio antenna of the present invention, when the rod-shaped antenna element is stored in the main body of the portable radio, the radio wave is transmitted and received at the gain characteristic of the cylindrical antenna element. In the state where the rod-shaped antenna element is pulled out from the portable wireless device main body,
Radio waves can be transmitted and received with the inherent gain characteristics of the rod-shaped antenna element, and the impedance characteristics of the cylindrical antenna element are well matched to the impedance characteristics of the rod-shaped antenna element. it can.

[Brief description of the drawings]

FIG. 1 is a partially broken front view showing an example of an embodiment of a portable wireless device antenna according to the present invention, wherein FIG. 1 (a) shows a state at the time of extension and FIG. 1 (b) shows a state at the time of storage. ing.

FIGS. 2A and 2B are perspective views showing a main part of the antenna for a portable wireless device shown in FIG. 1, wherein FIG. 2A shows a state of extension and FIG.

FIG. 3 is a Smith chart showing characteristics test results of the antenna according to the present invention.

FIG. 4 is a Smith chart showing another characteristic test result of the antenna according to the present invention.

FIG. 5 is a Smith chart showing characteristics test results of the antenna of the comparative example.

FIG. 6 is a Smith chart showing another characteristic test result of the antenna of the comparative example.

FIG. 7 is a perspective view of a portable wireless device on which a conventional antenna is mounted.

[Explanation of symbols]

1 rod-shaped antenna element, 2 cylindrical antenna element, 3 caps, 4 fittings 5 feeder, 7 matching circuit, 6 spring.

Claims (1)

[Claims] 1. A rod-shaped antenna element having the characteristics of a half-wavelength antenna and a cylindrical antenna element having the characteristics of an antenna of 1/4 wavelength or less and having an inner diameter larger than the outer diameter of the rod-shaped antenna element. And an antenna configured such that the cylindrical antenna element is fixed to the portable wireless device main body so that the rod-shaped antenna element can be pulled out or housed from the portable wireless device main body. When used by being pulled out from the wireless device main body, the base end of the rod-shaped antenna element and the base end of the cylindrical antenna element are connected to each other, and only the rod-shaped antenna element functions as an antenna; Is stored in the body of the portable wireless device, the connection between the rod-shaped antenna element and the cylindrical antenna element is disconnected, and Mobile phone antenna only the tubular antenna element is characterized by being configured to function as an antenna.