JPH0964624A - Auxiliray device for antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the gain of an antenna by mounting this antenna auxiliary device to a whip antenna fitted to a radio telephone set body to connect it. SOLUTION: An auxiliary antenna conductor 13 with λ/2 electric length is prepared so as to be fitted to the tip of a whip antenna 11 with the λ/2 electric length annexed to a portable telephone set 10. Since a pick part 12 composed of synthetic resin or the like which is used also as a protection member is formed on the tip part of a normal antenna 11, a mounting cap 14 annexed to the conductor 13 is engaged with the pick part 12. Thereby electrostatic capacity is generated between the cap 14 and the antenna 11 through the pick part 12, a high frequency current is supplied from the antenna 11 by high frequency coupling based upon the electrostatic capacity and the auxiliary antenna 13 with electric length corresponding to 1/2 high frequency current wavelength is resonated and radio waves are radiated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna auxiliary device which is used by being contactlessly coupled to an existing antenna, in particular, a whip antenna of a mobile phone or a specific low power radio which has been remarkably popular recently.

[0002]

2. Description of the Related Art Although various types of antennas are used in radio equipment, a whip antenna having a length of λ / 4 or λ / 4 is the most basic together with a dipole antenna having a length of λ / 2. This antenna is used as a standard when expressing the performance of the antenna. Because this whip antenna is small and has no directivity, it is often used in radios that are moved and used. If further miniaturization is required, insert an inductance etc. in the whip antenna. A so-called shortened antenna is used in which the electrical length is lengthened and the mechanical length is shortened as a result.

A λ / 4 whip antenna and an omnidirectional antenna will be described. In the present specification, the electric length is used to represent the length of the antenna unless otherwise specified. FIG. 1A is a schematic explanatory view of a λ / 4 whip antenna, and the λ / 4 whip antenna has a λ / 4 whip antenna.
A single conductor 1 having a length of / 4
A high-frequency power supply G that supplies high-frequency power by voltage feeding is connected between the base of the above and the ground 2. A high frequency wave having a wavelength corresponding to four times the electric length is supplied to the conductor 1 of the λ / 4 whip antenna, resonates, and is radiated into the air. As shown by the broken line in the figure, the current distribution at that time is maximum at the base, which is the feeding point, and minimum at the tip, which is the terminal.
On the contrary, the voltage distribution is minimum at the base, which is the feeding point,
It becomes the maximum at the tip, which is the end. Further, the radiated radio wave is radiated over the entire circumference in the direction perpendicular to the antenna element.

FIG. 1B is a schematic explanatory view of a λ / 2 whip antenna, which is composed of a single conductor 3 having a length of λ / 2. A high-frequency power source G ′ that supplies high-frequency power by current feeding is connected between the base of the conductor 3 and the ground 2.
A high frequency wave having a wavelength corresponding to twice the electric length is supplied to the conductor 3 of the λ / 2 whip antenna, resonates, and is radiated into the air. The current distribution at that time is as shown by the broken line in the figure,
The minimum is at the base, which is the feed point, and the front end, which is the end, and the maximum is at the center, and conversely, the voltage distribution is maximum at the base and the front end, which are the feed points, and maximum at the center. Further, the radiated radio wave is radiated over the entire circumference in the direction perpendicular to the antenna element. It should be noted that these whip antennas are attached with an inductance or capacitance for shortening the machine length at the base, if necessary.

In order to improve the gain of the antenna, a so-called omnidirectional antenna in which the gain in all directions is increased by increasing the number of radiators for entering and radiating the radio wave There is a so-called directional antenna in which the number of radiators to be used is one and the incoming and outgoing directions of radio waves are narrowed to increase the gain in a specific direction. FIG. 1C shows an outline of an omnidirectional antenna constructed based on the λ / 4 whip antenna. This omnidirectional antenna is the λ / 4 whip antenna shown in FIG. A high frequency power source G for supplying high frequency power by voltage feeding is connected between the base of the conductor 1 and the ground 2, and a conductor 4 having an electric length of λ / 2 is connected to the tip of the conductor 1. The number of conductors in the omnidirectional antenna is arbitrary. Shown in (d) is an outline of an omnidirectional antenna constructed based on a λ / 4 whip antenna. This omnidirectional antenna has a λ / shown in (b).
A high-frequency power source G ′ that supplies high-frequency power by current feeding is connected between the base of the conductor 3 of the 2 whip antenna and the ground 2, and a conductor 4 having an electrical length of λ / 2 is connected to the tip of the conductor 3. . The number of conductors in the omnidirectional antenna is arbitrary.

[0006] Some of these wireless telephones using a whip antenna have a structure in which the antenna can be replaced and a structure in which the antenna cannot be replaced. In the case of a wireless telephone whose antenna can be exchanged, the communication capability can be improved by exchanging it with an antenna having a large gain, but in the case of a wireless telephone whose antenna cannot be exchanged, such means Cannot be taken. Typical examples of devices in which the antenna cannot be replaced are a small-sized simplified wireless telephone, a portable telephone that has recently become popular, and a specific low-power communication device.

[0007] In the case of a simple type wireless telephone, the antenna is fixed to the main body of the wireless telephone due to price problems, and only the dedicated whip antenna attached to the wireless telephone can be used and other antennas can be used. It has a structure that cannot be replaced. Therefore, a wireless telephone in which these antennas cannot be replaced may not be able to perform desired communication in a bad environment.

The inventor of the present invention is a prior application, Japanese Patent Application No. 6-1908.
No. 9 proposes an antenna auxiliary device that can improve the gain of the entire antenna system without replacing the antenna attached to the communication device body.

FIG. 2 shows the antenna auxiliary device described in this prior application. The antenna auxiliary device shown in FIG. 2A is composed of a conductor 6 having a length of λ / 2, and the conductor 6 is attached to the tip of the λ / 4 whip antenna 1 of the high frequency voltage source G which is a communication device. The bases are arranged close together. As a result, the conductor 6 of the antenna auxiliary device is
/ 4 The whip antenna 1 is coupled to the tip of the whip antenna 1 by high-frequency coupling, and the high-frequency current fed from the high-frequency voltage source G to the whip antenna 1 is absorbed by the antenna auxiliary device 6 to absorb the high-frequency current. The conductor 6 of the device resonates and radiates radio waves all around.

This antenna auxiliary device is composed of a conductor 6 having a length of λ / 2. That is, this antenna auxiliary device is a resonator having a length of λ / 2 of the radio wave used. Therefore, this antenna auxiliary device resonates with respect to the absorbed radio wave and serves as a substantial antenna for the resonated radio wave, in other words, the λ / 4 whip antenna 1
Functions as a virtual antenna for the communication device to which the is attached and improves the gain.

The antenna auxiliary device shown in (a) is λ /
The conductor 6 having a length of 2 is brought close to and coupled to the tip of the λ / 4 whip antenna 1 of the communication device. However, not only the conductor 6 is made to approach but a part of the radiator 6 is parallel to the λ / 4 whip antenna 1. It is also possible to combine them by binding. (B) and (c) show an example in which a part of the conductor 6 is arranged in parallel with the λ / 4 whip antenna 1, and the conductor 7 of the antenna auxiliary device shown in (b) is λ. /
It has an electric length of 2, one end of which is arranged close to the tip of the λ / 4 whip antenna 1, and the central portion of which has λ /
It is arranged close to the base of the 4 whip antenna 1. The conductor 8 of the antenna auxiliary device shown in (c) is λ /
It has an electrical length of 4, and one end thereof is arranged close to the base of the λ / 4 whip antenna 1. In the case of these antenna auxiliary devices arranged in parallel, either capacitive coupling or electromagnetic inductive coupling occurs depending on the distance from the whip antenna, and the high frequency current fed from the high frequency voltage source G to the whip antenna 1 is The conductor of the antenna auxiliary device, which is absorbed by the antenna auxiliary device 7 or 8 and absorbs the high-frequency current, resonates and radiates radio waves to the entire circumference.
Note that the conductors of these antenna auxiliary devices can also have a multistage structure.

By the way, the most important usage form of the wireless telephone is "calling". In addition to "calling" to call the other party and "calling" to talk to the other party, the call from the other party is also used. There are "answers" to receive calls and "waits" for replies. The whip antenna attached to the wireless telephone is, of course, a protrusion that protrudes from the housing of the wireless telephone. It is often said that it can be stored. Such a whip antenna is often stored in the housing of the wireless telephone at times other than "call" or "calling" when it is necessary to maximize the communication capability of the wireless telephone. The gain of the whip antenna in the stored state is small. For this reason, there are some radio telephones in which a receiving diversity antenna is built in and shared with a whip antenna, but it is not possible to expect a sufficient gain in the built-in receiving diversity antenna.

Therefore, when the whip antenna is housed in the housing of the radiotelephone and the gain is extremely small, the identification information transmitted from the radiotelephone is not confirmed by the radiotelephone system. In some cases, a call cannot be made because it is judged to be out of the calling range or the power is cut off.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to secure the gain of a whip antenna attached to a wireless telephone in order to deal with such a situation. Providing a specific mounting structure for application to a telephone, and ensuring a gain even when the whip antenna attached to the wireless telephone is housed in the casing of the wireless telephone It is an object of the invention to provide the above.

In order to achieve these objects, in the present application, the structure of the antenna auxiliary device is such that the structure of the base is mechanically coupled to the tip of the whip antenna and is also coupled at high frequency, and further, We propose a structure of the main body of the antenna auxiliary device in which the radiator is composed of a flexible conductor.

The antenna auxiliary device having these configurations can be easily attached to the whip antenna attached to the wireless telephone. Further, when the radiator is made of a flexible conductor, the radiator exists outside the housing even when it is housed in the housing, so that the gain can be secured and even if it exists outside the housing, it is an obstacle. Never be.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The number of radio waves used is 800 for mobile phones that have become very popular recently.
There are telephones in the MHz range and 1500 MHz. When the radio wave used is 800 MHz, the wavelength is 37.5 cm, so λ / 4 is 9.375 cm, and the radio wave used is 1500.
Since the wavelength in the case of MHZ is 20.0 cm, λ / 4 becomes 5.0 cm, so that the electric length of the whip antenna used in the mobile phone is often λ / 2. In the case of the invention of the prior application shown in FIG. 2, only a whip antenna having an electric length of λ / 4 is targeted, but a whip having an electric length of λ / 2 is considered in consideration of use in a portable telephone. The antenna also needs to be targeted.

Shown in FIG. 3 is a first embodiment of the present invention. In this figure, (a) shows a state in which the whip antenna 11 is extended outside the housing of the mobile phone 10, and (b) shows a whip antenna 11.
Is stored outside the housing of the mobile phone 10. The antenna auxiliary device of the first embodiment is a conductor 13 also having an electric length of λ / 2, which is attached to the tip of a whip antenna 11 having an electric length of λ / 2 attached to the mobile phone 10. It is configured. The high frequency coupling of the conductor 13 with the whip antenna 11 is a metallic mounting cap 1 which is elastically attached to the tip of the whip antenna.
4 and the whip antenna 11 provide the electrostatic capacitance present.

In the case of an ordinary whip antenna, since the knob 12 made of synthetic resin or the like also serving as a protective member is provided at the tip, a metallic mounting cap 14 is fitted to the knob 12 made of synthetic resin. After being attached, a capacitance is generated between the mounting cap 14 and the whip antenna 11 via the synthetic resin which is an insulator. The whip antenna 11
If the conductor is exposed because the knob portion 12 made of a synthetic resin is not provided at the tip of the or the knob portion 12 is made of a conductor, a synthetic resin layer is provided inside the mounting cap 14. By forming the mounting cap 14
An electrostatic capacitance is generated between the whip antenna 11 and the whip antenna 11. The antenna auxiliary device having such a configuration includes the knob 1
A high frequency current is supplied from the whip antenna 11 by the high frequency coupling caused by the electrostatic capacitance generated between the tip of the whip antenna 11 and the mounting cap 14 via 2, and the half of the wavelength of the supplied high frequency current is supplied. An antenna auxiliary device having an electrical length resonates and radiates radio waves. In this embodiment, the whip antenna 11
Although the electrical length of the above is described as λ / 2, the same operation is possible even when the electrical length is λ / 4.

Shown in FIG. 4 is the first shown in FIG.
It is the 2nd Example which improved the Example. In this figure,
(A) shows a state where the whip antenna 11 is extended outside the housing of the mobile phone 10, and (b) shows that the whip antenna 11 is stored outside the housing of the mobile phone 10. It is in the state of having done. The antenna auxiliary device according to the second embodiment is also attached to the mobile phone 10 and is attached to the tip of the whip antenna 11 having an electric length of λ / 2, and is also flexible having an electric length of λ / 2. Conductor 15
It is composed of The high frequency coupling of the flexible conductor 15 with the whip antenna 11 is provided by the electrostatic capacitance existing between the whip antenna 11 and the metallic mounting cap 16 attached to the tip of the whip antenna.

As the flexible conductor 15, a conductive wire having an insulating coating is desirable from the viewpoint of protecting the flexible conductor. Further, when the tip portion of the whip antenna is provided with a synthetic resin knob 12 which also serves as a protection member, a metallic mounting cap 16 is fitted to the synthetic resin knob 12, If the conductor is exposed because the knob portion 12 made of synthetic resin is not provided at the tip of the antenna or the knob portion 12 is made of a conductor, the synthetic resin layer is formed inside the mounting cap 16. To form.
The mounting cap having this structure can also be mounted on a whip antenna provided with a synthetic resin knob 12 that also functions as a protective member at the tip of the knob.

FIG. 5 shows the third embodiment, and unlike the first and second embodiments, the antenna auxiliary device is arranged in parallel with the whip antenna. In this figure,
A conductor 19 of an antenna auxiliary device having an electric length of λ is arranged in parallel with a whip antenna 17 having an electric length of λ / 2 attached to the mobile phone 10. Reference numerals 18 and 20 denote protective knobs attached to the tips of the whip antenna 17 and the conductor 19.

In this embodiment, the conductor 19 of the antenna auxiliary device is parallel to the whip antenna 17 at a predetermined interval, and the high frequency current supplied to the whip antenna 17 induces a high frequency current in the conductor 19. Radio waves are radiated from the conductor 19 by the high frequency current.
In this case, if the length of the conductor 19 is selected to be an electrical length slightly different from the wavelength λ of the high frequency current, the antenna system including the whip antenna 17 and the conductor 19 can have directivity. Although the whip antenna 17 has an electrical length of λ / 2 and the conductor 19 has an electrical length of λ in this embodiment, the same operation is performed even when the electrical lengths are λ / 4 and λ / 2, respectively. Is possible. Further, when the whip antenna 17 can be housed outside the housing of the mobile phone 10, the antenna auxiliary device can also be made telescopic by adopting a telescopic structure or the like.

FIG. 6 shows a fourth embodiment of the present invention, in which the antenna auxiliary device is arranged in parallel with the whip antenna as in the third embodiment. In this figure,
(A) shows the antenna auxiliary device in a stretched state, and (b) shows the antenna auxiliary device in a contracted state. In this figure, the total electrical length of the conductor 23 and the conductor 24 is λ in parallel with the whip antenna 21 of electrical length λ / 2 attached to the mobile phone 10.
An antenna auxiliary device having a telescopic structure or the like that can be stored in the conductor 24 is arranged. 22 and 2
Denoted by 5 is a protective knob attached to the tips of the whip antenna 21 and the conductor 23.

In this embodiment, the conductors 23 and 24 of the antenna auxiliary device are parallel to the whip antenna 21 at a predetermined interval, and the high frequency current supplied to the whip antenna 21 induces a high frequency current in the conductors 23 and 24. , The conductors 23 and 2 by the induced high frequency current
Radio waves are radiated from 4. Also in this case, if the length of the conductors 23 and 24 is selected to be an electrical length slightly different from the wavelength λ of the high frequency current, the whip antenna 21 and the conductors 23 and 24 are selected.
It is possible to give directivity to the antenna system configured by. In this embodiment, the whip antenna 21
However, the same operation is possible even when the electrical lengths of the conductors 23 and 24 are λ / 4 and λ / 2, respectively. When the whip antenna 21 can be stored outside the housing of the mobile phone 10, the antenna auxiliary device shortened by the telescopic structure or the like is installed outside the housing of the whip antenna 2.
It can be stored at the same height as 1.

Finally, with reference to FIG. 7, a structure for attaching the antenna auxiliary device to a mobile phone or a specified low power radio will be described. For convenience of explanation, this figure shows the case of using it for a mobile phone, but these mounting structures are more effective when used for a specific low-power radio than the mobile phone. One example of a structure for mounting the antenna auxiliary device to the whip antenna is a mounting structure using a mounting cap as shown in FIGS. Since this mounting structure uses the rod-shaped knob at the tip of the whip antenna, if the knob has a flat plate shape as shown in FIG. 5, the mounting structure using this mounting cap is adopted. Can not do it. In such a case, FIG.
As shown in (a), an antenna assist is provided by using an insulating elastic clip 31 formed of synthetic resin or the like at the end of the whip antenna near the flat plate-shaped grip portion 28 of the whip antenna 27 of the mobile phone 10. Attach the device 29.
In this case, the electrostatic capacitance 32 generated between the lower end of the antenna auxiliary device 31 and the upper end of the whip antenna 27 causes the antenna auxiliary device 31 to be coupled to the whip antenna 27 at high frequency. It should be noted that this mounting structure can also be adopted for a whip antenna having a bar-shaped grip portion or a whip antenna having no grip portion at all.

In the case of the mounting structure using the mounting cap as shown in FIGS. 3 and 4, if the length of the auxiliary antenna is large, the load on the mounting cap becomes large and the antenna auxiliary device having a large gain is installed. It is difficult to use. In such a case, a pipe 36 formed of an insulator made of synthetic resin or the like, into which the entire whip antenna 33 of the mobile phone 10 can be inserted, is provided at the base of the conductor 34 of the antenna auxiliary device. The whole whip antenna 33 is configured to be inserted. In this case, the electrostatic capacitance 37 generated between the lower end of the antenna auxiliary device 34 and the upper end of the whip antenna 27 causes the antenna auxiliary device 34 to be coupled to the whip antenna 33 at high frequency. In this embodiment, the pipe 36 is provided at the base of the conductor 34. However, if it is necessary to secure the attachment strength between the pipe 36 and the conductor 34, the pipe 36 should be extended in the distal direction of the conductor 34. Therefore, the conductor 34 is also inserted into the pipe 36. If a sufficient electrostatic capacity cannot be ensured between the lower end of the antenna auxiliary device 34 and the upper end of the whip antenna 27, a conductor pipe connected to the antenna auxiliary device 34 should be provided at the upper end of the pipe 36. Form. Further, the antenna auxiliary device may have a telescopic structure for the pipe 36 and the conductor 34 so that the antenna auxiliary device can be stored easily when not in use.

As is apparent from the configuration of the prior application shown in FIG. 2, the antenna auxiliary device is arranged on the same axis with respect to the whip antenna as shown in FIG. In some cases, the antenna auxiliary devices are arranged on the same axis with respect to the whip antenna, although they may be arranged on parallel axes as shown in b) and (c). It is about the case.
A mounting structure in the case where the antenna auxiliary device is arranged on the parallel axis with respect to the whip antenna will be described with reference to FIGS.

FIG. 7C shows a structure for attaching the antenna auxiliary device 40 to the whip antenna 38 of the mobile phone 10. Antenna auxiliary device is conductor 4
0 and the conductor 41 are connected by a telescopic structure, and the base of the conductor 41 is fixed to one end of a plate-shaped mounting member 43 made of an insulating material such as synthetic resin. Further, an insertion hole 44 is formed at the other end of the attachment member 43 in parallel with the conductor 41, and the antenna auxiliary device is attached to the mobile phone 10 by inserting the whip antenna 38 into the insertion hole 44. . Mounting member 4
3 is attached to the whip antenna 38 by simply inserting the through hole 4
It is possible to just insert the whip antenna 38 into 4,
In order to make the attachment firm, the insertion hole 43 is formed with an elastic holding portion. Although the lower end of the conductor 41 is lower than the upper end of the casing of the mobile phone 10 in this figure, in such a state, the lower end of the conductor 41 is arranged on the back or the whole of the casing of the mobile phone. Further, when the lower end of the whip antenna 38 is above the upper end of the housing, the lower end of the conductor 41 need not be below the upper end of the mobile phone 10.

FIG. 7D shows a structure for attaching the antenna auxiliary device 40 to the housing of the mobile phone 10. The antenna auxiliary device has a structure in which a conductor 47 and a conductor 48 are joined by a telescopic structure, and an upper portion of the conductor 48 is fixed to one end of a plate-shaped mounting member 50 made of an insulating material such as synthetic resin. The attachment member 50 is fixed to the housing of the mobile phone 10 by an appropriate means such as a surface fastener. In this figure, the conductor 4
7 has a structure in which the conductor 48 is connected by a telescopic structure, but when the electric length of the antenna auxiliary device is equal to the electric length of the whip antenna 45, such a structure is not necessary. 7 (b), (c) and (d), 35, 39, 42, 46 and 49 are
Each is a knob provided on the whip antenna or the antenna auxiliary device.

The coupling between the whip antenna and the antenna auxiliary device in the embodiments shown in FIGS. 3 and 4 and the embodiment shown in FIG. 7B described above is described as capacitive coupling, and The coupling between the whip antenna and the antenna auxiliary device in the other embodiments was not particularly described. The high frequency coupling between the antenna and the adjacent conductor that is excited at a high frequency may be capacitive coupling or inductive coupling depending on the distance and arrangement relationship between the two. Therefore, what kind of high-frequency coupling should be used can be appropriately determined when designing the antenna auxiliary device.

[0032]

As is apparent from the above description, the antenna auxiliary device of the present invention can be easily attached to a radio telephone, and by attaching and coupling it to a whip antenna attached to the radio telephone main body. The antenna gain can be improved. Further, when the antenna auxiliary device is configured with a flexible conductor, the gain of the antenna system can be secured even when the whip antenna is stored in the housing of the wireless telephone. It doesn't get in the way.

[Brief description of drawings]

FIG. 1 is a conceptual explanatory diagram of a whip antenna and an antenna.

FIG. 2 is a conceptual explanatory view of an antenna auxiliary device of the invention of the prior application.

FIG. 3 is a conceptual explanatory diagram of an antenna auxiliary device according to the first embodiment of the present invention.

FIG. 4 is a conceptual explanatory diagram of an antenna auxiliary device according to a second embodiment of the present invention.

FIG. 5 is a conceptual explanatory diagram of an antenna auxiliary device according to a third embodiment of the present invention.

FIG. 6 is a conceptual explanatory diagram of an antenna auxiliary device according to a fourth embodiment of the present invention.

FIG. 7 is an explanatory view of an example of mounting means of the antenna auxiliary device of the present invention.

[Explanation of symbols]

10 Mobile phone G, G'High frequency power source 1, 11, 17, 21, 27, 33, 38, 45 Whip antenna 6, 7, 8, 13, 15, 19, 23, 24, 29, 3
3,34,40,41,47,48 Conductor 12,18,20,22,25,28,30,35,3
9, 42, 46, 49 knob part 14, 16 mounting cap 36 mounting pipe 31, 43, 50 mounting tool 44 insertion hole 32, 37 coupling part

Claims (3)

[Claims] 1. An antenna auxiliary device coupled to a whip antenna belonging to a portable wireless telephone, wherein the antenna auxiliary device has a conductor having a length that resonates with a radio wave used, and the conductor is connected to the whip antenna. An antenna auxiliary device having a coupling part for coupling. 2. The antenna auxiliary device according to claim 1, wherein the coupling portion is a capacitive coupling portion attached to a tip of the whip antenna. 3. The antenna auxiliary device according to claim 2, wherein the conductor is a flexible conductor.