JP2989946B2 - Telescopic telescopic antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telescopic antenna device which uses a duplexer to share a carrier wave transmitted and received by a cellular telephone, a portable telephone or the like in an ultra-high frequency band via a duplexer. It is characterized in that an impedance matching unit capable of equivalently moving a feeding point to the antenna by electrostatic coupling is provided.

[0002]

2. Description of the Related Art An antenna used in a portable cellular telephone is configured such that a conductor (passive element) having a length of λ / 4 is appropriately proportional to a ground conductive portion of a housing of the telephone body. It is easy to match with the radio circuit, especially the high frequency part, but if you hold the phone with your hand and put the earpiece on your ear because of the grounding type, the efficiency as a ground radiator will be degraded. As a measure, a quarter-wave radiator had to be separately installed at right angles to the spiral antenna.

Another prior art employs a configuration in which the amount of projection of a linear conductor that can move within a sleeve-like conductor from the sleeve-like conductor is set in accordance with a plurality of effective antenna lengths. This is provided with a variable impedance matching section corresponding to the detected value of the amount of protrusion of the linear conductor.

[0004]

Therefore, in the former prior art described above, one method for compensating for the deterioration of the efficiency of the radiator is described.
Since the / 4 radiator must be arranged orthogonally to the spiral antenna, it does not meet the requirements for extremely small size and light weight, such as a portable telephone, and has a decent antenna performance. is not.

Further, in the latter prior art, a separate component must be provided to detect the amount of protrusion of the rod-shaped antenna from the sleeve-shaped antenna and to form an impedance matching section responsive to the detected amount. This is even an obstacle to miniaturization and weight reduction.

Thus, the present invention solves the above-mentioned drawbacks by providing impedance matching between a spiral antenna and a rod antenna which can be used for transmitting and receiving carriers of a small and lightweight telephone in an ultra-high frequency band without any external components. The telescopic antenna can be removed.

[0007]

According to the present invention, there is provided a housing of a radio device having a deep hole having a guide wall which is housed over substantially the entire length of a rod-shaped antenna, and a coaxial center formed by an opening edge of the deep hole. A spiral antenna having an input end as a feeding point, and a rod-shaped antenna having a core layer conductor covered with an insulating sheath and having a conductive layer divided on a base surface thereof; When the antenna is pulled out of the housing, it is grounded and forms an impedance matching section in which stray capacitance between the spiral conductor of the spiral antenna and the stray capacitance terminates in parallel. The rod antenna is moved near the output end of the linear antenna, and when the rod antenna is pulled out, part or all of the spiral antenna matches the impedance of the rod antenna to adjust the length of the rod antenna. Pick also it is an unsusceptible ungrounded antenna device influences the human body.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. First, FIG. 1 is a longitudinal sectional side view of a telescopic antenna device of the present invention. FIG. 1A is a diagram showing a state in which a rod-shaped antenna 1 is housed in a guide deep hole 5 of a housing 4, and FIG. FIG. 6 is a partially cut-out state drawing drawn outward so that the bulging portion of the rod-shaped antenna base stops at the position shown in FIG. 2 is housed in the coil holding body 3, the guide expressive hole and disposed on the coaxial center line has spiral-shaped antenna, 6 feeder cable 7 in the housing to the input terminal of the spiral-shaped antenna and the feed point S ₁ A stopper engaging portion 9 provided on a bulging surface of the base of the rod-shaped antenna is shown in FIG.
The elastic stopper is fitted and grounded when it is pulled out as shown in FIG. 2. The rod-shaped antenna has an insulated core conductor (radiator) 1-1 as shown in FIG. It is embedded in the sheath, extends to the neck of the bulged portion having the inner diameter of the connected deep slot, and is electrically connected to the conductive layer 1-2 provided separately on the outer surface thereof. I have.

Now, it can be seen from the schematic diagram of FIG. 2 that a rod-shaped antenna provided with a conductive layer provided on the surface of the swollen portion is drawn out through the hollow portion of the spiral antenna. , in between the conductive layers 1-3 of the screw engagement conductors and the rod-shaped antenna of spiral-shaped antenna, the stray capacitance C ₁ -C ₄ occurring contribute rod-shaped antenna impedance matching to the surroundings as a coaxial center like Are connected in parallel. At this time, the spiral conductor near the output end of the spiral antenna is electrically coupled as indicated by the dotted line near the boundary of the bulging portion of the rod antenna. This dotted line part is a rod-shaped antenna that moves up and down, so there is no contact by the elastic contact or the capacitor counter electrode,
What is necessary is just to electrically connect with the outer surface conductive part of the base part of a rod-shaped antenna.

FIG. 3 is a schematic view of an essential part of a rod-shaped antenna which is drawn out through a hollow portion of the spiral antenna by an electric equivalent circuit. They are connected in parallel with the spiral conductors of the antenna and are inserted in such a manner that they are terminated to the ground, and impedance matching is measured. At this time, the feeding point S ₁ at the input end of the spiral antenna moves to S ₂ near the output end thereof, and the rod-shaped antenna is connected ahead of it. , The rod-shaped antenna will not be hidden by the human body, especially the head, so that the efficiency of the radiator is avoided.

With the above antenna configuration, when the rod antenna is housed in the housing, the spiral antenna functions as a current feeding type, and when the rod antenna is pulled out, it functions as a voltage feeding type.

[0012]

As described above, the telescopic antenna device of the present invention is accommodated in the narrow space in the housing of the portable telephone body without being hindered, and the rod antenna is passed through the hollow portion of the spiral antenna. When pulled out, the feed point can be moved from the input end to the vicinity of the output end of the spiral antenna by using the impedance matching by the stray capacitance coupling with the base of the rod-shaped antenna. It does not require any additional elements, such as a detecting and adjusting means, and can satisfy the radiation characteristics as an antenna while sufficiently responding to the demand for a small and lightweight telephone.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a telescopic antenna device of the present invention,
(A) shows a state where the rod-shaped antenna is housed in the deep guide hole in the housing, and (B) shows a state where the rod-shaped antenna is drawn out of the housing.

FIG. 2 is a schematic diagram of a main part of FIG. 1 (B).

FIG. 3 is an electrical equivalent circuit diagram of FIG. 2;

[Explanation of symbols]

Reference Signs List 1 rod antenna 1-1 core conductor 1-2, 1-3 conductive layer 2 spiral antenna 3 coil holder 4 housing 5 guide long hole 6 cable insertion hole 7 power supply cable 8 elastic stopper 9 stopper engaging portion C ₁ -C ₄ stray capacitance S _1, S ₂ feed point

Claims (1)

(57) [Claims] 1. A telescopic radio device in which impedance matching is achieved by electrical coupling between a spiral antenna corresponding to a transmission / reception carrier frequency and a part of a λ / n-length rod antenna coupled to the spiral antenna. In telephone antennas,
A housing for a radio device having a deep hole with a guide wall accommodated over substantially the entire length of the antenna, and a spiral wire arranged at the coaxial center at an opening edge of the deep hole and having an input end as a feeding point; Antenna and a rod-shaped antenna that covers the entire core conductor with an insulating sheath and has a conductive layer divided on the base surface thereof, and is grounded when the rod-shaped antenna is pulled out of the housing. Forming an impedance matching section in which the stray capacitance between the spiral conductor of the spiral antenna and one of the conductive layers is terminated in parallel,
A telescopic antenna device for a radio telephone, wherein the feeding point is moved to a position near an output end of the spiral antenna.