JPH08237016A - Connection method for helical top antenna and its connection structure - Google Patents

Abstract

PURPOSE: To reduce cost by allowing a composite antenna to be in capacitive coupling with a high frequency circuit so as to activate the antenna in the intermediate posture between the extended posture and the contained posture thereby avoiding improper electric contacts and increasing the mechanical strength. CONSTITUTION: A printed circuit board 4 with a high frequency circuit formed is placed in a case 1. Furthermore, in a helical top type composite antenna element 7, a helical antenna 7b whose electric length is λ/2 is fixed and in electric continuity to one end of a wire antenna 7a whose electric length is λ/2. Furthermore, a made guide sleeve 8 made of synthetic resin supporting the wire antenna 7a slidably and freely is fixed through a top wall of the case 1. Then the composite antenna element 7 is moved vertically and an exciter 10 is provided, which is located opposite to the λ/2 wire antenna 7a over the entire vertical movement stroke and apart therefrom and resonated at a length of λ/4. An open end 10a of the λ/4 exciter 10 is opposed to the λ/2 wire antenna 7a and is separated from it and a static coupling capacitance (c) is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mechanically supports a helical top type antenna when it is supported so as to extend and contract with respect to a case of a radio device, and electrically supports the helical top type antenna electrically. It is about connection technology.

[0002]

2. Description of the Related Art In a small mobile communication device, especially a portable radio telephone, it is desired that an antenna be expanded and contracted so that it can be carried easily, and it is necessary that an incoming call can be detected even in a contracted state. And That is, in the stored state, the sensitivity may not be as high as in the normal use state, but it is desired to maintain a certain level of sensitivity. A technique for providing a built-in antenna is known as a device that meets such a demand. However, it is necessary to provide a switch means for switching the built-in antenna and a telescopic antenna, and the high frequency radiated from the built-in antenna is used in other mounted products. Use of the built-in antenna because it must be equipped with a means to prevent it from affecting, and it is necessary to devise that the radio wave received by the built-in antenna is not blocked by the hand holding the mobile phone. Are subject to various constraints.

As a technique for detecting an incoming call even when the retractable antenna is housed without using a built-in antenna, a helical top system is used in which a helical antenna and a linear antenna are connected in series to conduct electricity. It is known to use antennas. If the helical top antenna is applied, the incoming call can be detected by making the helical antenna part project outside the case of the portable wireless telephone even in the stored posture. Then, by extending the linear antenna portion outside the case, a stable call can be obtained. As a recent technique for supporting a helical top type antenna so as to extend and contract with respect to a case of a mobile radio telephone and electrically connecting the antenna to a high-frequency circuit of the mobile radio telephone, Japanese Patent Laid-Open No. 6-58242 is known. −
The antenna disclosed in 196912 and US Pat. No. 5,204,687 (Apr. 20.19).
93) is known. In the present invention, “conductivity” refers to direct current coupling in which ohmic resistance is reduced by contact between electric conductors. Further, the term "electrical connection" has a wide meaning including not only the above-mentioned conduction but also high frequency coupling by electromagnetic response. That is, (electrical connection) = (direct current conduction) + (high frequency coupling).

Next, the above-mentioned known technique will be described by sequentially explaining FIGS. 5 and 6. FIG. 5 shows JP-A-6-19.
6 shows a known antenna disclosed in No. 6912, (A)
Is a vertical cross-sectional view schematically showing a state in which most of the linear antenna portion is drawn out of the case and extended, and (B) is a case where the linear antenna portion is pushed into the case and housed, and only the helical antenna portion is the case. FIG. 3 is a vertical cross-sectional view schematically illustrating a state in which it is projected to the outside. Reference numeral 1 is a case of a portable wireless telephone, and 2 is a helical top type composite antenna.
The composite antenna 2 is configured such that a helical antenna 2b having an electrical length of 1/4 wavelength is mechanically connected to the upper end of a linear antenna 2a having an electrical length of 1/4 wavelength and electrically connected to the helical antenna 2b. The sleeve-shaped conductive terminal 3 is fixedly inserted through the case 1. The electrical length of 1/4 wavelength means to resonate at 1/4 wavelength, and is abbreviated as λ / 4 hereinafter. Similarly, λ / 2 described below also intends to resonate at a half wavelength.

The extended posture in which the composite antenna 2 is pulled out upward as shown in FIG. 5 (A) is in a normal use state used for a call, and at this time, the base end portion of the composite antenna 2 is circuited. In order to conduct electricity to the substrate 4, a lower conducting portion 2c which is closely fitted to the sleeve-like conducting terminal 3 is formed at the lower end portion of the λ / 4 linear antenna 2a. Also, FIG.
As shown in (B), the storage posture pushed downward is in a state of being used when being carried, and since the λ / 4 helical antenna portion 2b projects out of the case 1, it is possible to detect an incoming call. In order to electrically connect the composite antenna 2 to the circuit board 4 in this state, an upper conducting portion 2d which is closely fitted to the sleeve-like conducting terminal 3 is formed at the upper end portion of the λ / 4 linear antenna 2a. Then, in the storage posture described above, λ / 4
An earth contact piece 5 is provided which grounds the lower end of the linear antenna 2a (specifically, conducts the earth circuit of the circuit board 4).

The connection structure of the helical top antenna according to the above-mentioned US patent is similar in appearance to the antenna of FIG. 5 described above, but the electrical conduction state is basically different.
FIG. 6 shows a connection structure of a helical top antenna according to US Pat. No. 5,204,687, and FIG. 6A schematically shows a state in which a linear antenna portion of a composite antenna is pulled out upward, and FIG. FIG. 6 is a vertical cross-sectional view of the publicly known example shown in FIG. 5, and (B) schematically illustrates a state in which the linear antenna portion is housed in a case, and illustrates the housed state of the publicly known example shown in FIG. 5. It is a vertical cross-sectional view corresponding to FIG. Considering the difference between the configuration shown in FIG. 6 and the configuration shown in FIG.
a and the helical antenna 6c are mechanically connected to each other via the electric insulator 6e and are not electrically connected.
A part of the electric insulator 6e encloses the linear antenna 6a. When the composite antenna 6 is extended as shown in FIG. 6 (A), the linear antenna 6a is electrically connected to the circuit board 4,
The structure in which a large-diameter linear antenna conducting portion 6b is formed at the lower end portion of the external linear antenna 6a so as to be closely fitted to the sleeve-shaped conducting terminal 3 is similar to that shown in FIG. When the composite antenna 6 contracts as shown in FIG. 6 (B), the helical antenna 6c is electrically connected to the substrate 4,
The helical antenna conducting portion 6d is the helical antenna 6c.
The helical antenna conducting portion 6d is tightly fitted to the sleeve-like conducting terminal 3. In this state of FIG. 6 (B), since the linear antenna 6a is not electrically connected to the sleeve-shaped conductive terminal 3, the means for grounding the linear antenna 6a (a member corresponding to the ground contact piece 5 in FIG. 5) is Not provided.

[0007]

Due to the structure in which the helical top type composite antenna is slidably supported, the incoming call can be detected even in the stored posture without using the built-in antenna, and the extended posture is favorable. The basic technique of obtaining high reception sensitivity is publicly known. However, the characteristics of the helical top type composite antenna change depending on how it is mechanically supported and how it is electrically connected. Therefore, if you try to apply this to a portable wireless telephone,
A technical improvement is how to maximize the various characteristics required for a portable wireless telephone.
It emerges in the focus of ingenuity. The main characteristics required are a. Functions as an antenna even in an intermediate state between the extended posture and the stored posture. B. No electrical continuity will occur in the electrical contacts when the antenna is stored or extended. C. Sufficient mechanical strength and excellent durability. D. The storage and extension operations are performed smoothly and the operation feel is good. E. It is waterproof and rainwater does not enter the case through the sliding parts of the antenna. F. It has excellent electrostatic withstand voltage. G. To obtain the highest possible gain. J. Manufacturing cost is low. Is mentioned. Completely fulfilling all these items is
Although it is considered that it is difficult as a practical problem to be almost impossible, the engineers related to the antennas of the mobile radio telephones have tried to obtain the characteristics as close to perfect as possible for as many items as possible. I am continuing my research.
The two known inventions described above as the prior art have respective advantages, but also have respective disadvantages.

An engineer who is involved in the comprehensive development of a mobile wireless telephone will understand the advantages and disadvantages of each method and then select a method suitable for the specifications and usage conditions of the mobile wireless telephone to be developed. Therefore, as an antenna-related development engineer, even if it is not perfect, it is possible to contribute to the development of the portable radio telephone industry by creating a method having different lengths from the two known inventions. . Of course, it is the duty of an antenna engineer to meet the social demands to make more perfect characteristics for more requirements. The two publicly known inventions described above each have a high value as pioneering creations of technological progress, but in order to further explore the room for improvement, the above-mentioned two inventions are added to each of the items a to h. Considering the characteristics of, it is as follows.

A. Regarding the antenna performance in an intermediate state, the invention disclosed in Japanese Patent Laid-Open No. 6-196912 shown in FIG. 5 (hereinafter abbreviated as the invention of FIG. 5) is also disclosed in US Pat.
No. 5.204,687 (hereinafter, abbreviated as the invention of FIG. 6) also has a structure in which it is electrically connected to the sleeve-shaped conductive terminal 3 in the extended (A) view and the stored (B) view, respectively. Yes, conduction is interrupted in the intermediate state of extension and storage (specifically, conduction is extremely unstable in the invention of FIG. 5 and completely insulated in the invention of FIG. 6). Therefore, it cannot function as an antenna in the intermediate state of extension and storage. B. Regarding the fear of defective conduction, in both the invention of FIG. 5 and the invention of FIG. 6, the conduction switching between the extended state of FIG. 5A and the stored state of FIG. Since it depends on the continuity due to, it is difficult to ensure the continuity of the poor continuity due to rusting or the entrapment of foreign matter. C. Regarding the mechanical strength, since the composite antenna 6 according to the invention of FIG. 6 mechanically connects the helical antenna conducting portion 6d and the linear antenna 6a via the electrical insulator 6e, the mechanical strength is not sufficient. Especially, when it is subjected to a bending external force, it is easily broken. Further, in the invention of FIG. 5, in the intermediate state of extension and storage,
The sleeve-shaped conducting terminal 3 and the linear antenna 2a are fitted with each other with a large amount of play and rattling, so that the sleeve is easily damaged unless handled very carefully. D. Regarding the operation feeling, in the invention of FIG. 5, the operation feeling is not good because it rattles in the intermediate state of extension and storage as described above. In the invention of FIG. 6 as well, if the sleeve-shaped conducting terminal 3 and the linear antenna conducting portion 6b are surely conducted to each other and the sleeve-shaped conducting terminal 3 and the helical antenna conducting portion 6d are surely conducted to each other, the The operation feeling is not smooth because the fitting must be tight. Further, if a strong spring piece is attached to the sleeve-shaped conductive terminal 3 in order to ensure the conduction, new problems such as a complicated structure and an increase in manufacturing cost and a problem of spring fatigue are derived. . E. With respect to waterproofness, the invention of FIG. 5 has a sleeve-shaped conducting terminal 3 and a linear antenna 2 in an intermediate state between the extended posture (FIG. A) and the storage posture (B).
There is nothing to block the infiltration of water from the gap with a, and there is no waterproof property. In the invention of FIG. 6, in order to allow sliding of pulling out / pushing in when the composite antenna 2 is extended / stored, an appropriate clearance is required between the composite antenna 2 and the sleeve-shaped conducting terminal 3, and external water (for example, raindrops) is required. Cannot be prevented. F. Regarding the electrostatic withstand voltage, since the invention of FIG. 6 is provided with the electric insulator 6e, it is possible to take the electrostatic withstand voltage by covering the sleeve-shaped conducting terminal 3 with an insulator, but a structural ingenuity is required. is there. G. Regarding the gain, since the electrical length of the helical antenna is λ / 4 and the electrical length of the linear antenna is also λ / 4, there is an advantage that the mechanical shape can be made small, but the gain should be increased. There is a limit about.

The present invention has been made in view of the above circumstances. (A) It functions as an antenna in an intermediate state between the extended posture and the stored posture, and (b) causes a trouble such as poor continuity of electrical contacts. (C) It has high mechanical strength and excellent durability, (d) it has a smooth extension / storing operation and a good operation feeling, and (e) is suitable for taking a waterproof structure. ) An object of the present invention is to provide a simple and low-cost method for connecting a helical top antenna and a structure for connecting the same, which is excellent in electrostatic withstand voltage and (g) provides high gain. However, the expression of characteristics such as excellent or good is
This is a relative meaning based on the known inventions of FIGS. 5 and 6.

[0011]

In order to achieve the above-mentioned object (all items of A to E), a method of connecting a helical top antenna according to the present invention is a method of connecting a helical top system in a case in which a high frequency circuit of a radio device is housed. A method of attaching an antenna, mechanically supporting the antenna, and electrically connecting the antenna to a high frequency circuit, wherein one end of a linear antenna having an electrical length of about ½ wavelength , A helical antenna having an electrical length of about 1/2 is connected, and mechanically directly contacted and electrically conducted to form a helical top type composite antenna element, and the helical antenna is positioned outside the case. The linear antenna is slidably supported by penetrating the wall of the case, and the linear antenna is electrically connected to the high-frequency circuit without mechanical contact. Even opposition without conductive, electromagnetically coupled via the electrostatic capacitance, and, from the point at which the filament antenna are capacitively coupled to the high-frequency circuit,
"One side where the helical antenna is connected to the linear antenna"
When viewed in the opposite direction, the impedance is markedly higher than the impedance on the antenna side. As a mode recommended when carrying out the method of connecting the helical top antenna according to the present invention, when the composite antenna element is slid in the direction to be pushed into the case, the linear antenna is used for a high frequency circuit. Insert the "side not connected to the helical antenna" into the conductive tube or ring rather than the point where it is capacitively coupled, and ground the tube or ring to the above It is desirable to increase the impedance on the side not connected to the helical antenna so that it is significantly higher than the impedance on the antenna side, and to isolate this part from the circuit to prevent the influence on the high frequency circuit. .

Further, the connection structure of the helical top antenna of the present invention constructed so as to be suitable for carrying out the method of the present invention is as follows:
In a structure in which a helical top type antenna is attached to a case accommodating a high frequency circuit of a radio device, the antenna is mechanically supported, and the antenna is electrically connected to the high frequency circuit, the electrical length is At one end of the linear antenna, which is about 1/2 wavelength, the electrical length is about 1/2.
The helical antenna is connected to form a helical top type composite antenna element.The helical antenna is positioned outside the case, and the linear antenna is slidably supported through the wall of the case. The linear antenna is opposed to the high-frequency circuit without being in direct mechanical contact with the high-frequency circuit, is electrically non-conducting, and is electromagnetically coupled through a capacitance, and From the point where the wire antenna is capacitively coupled to the high frequency circuit,
"One side where the helical antenna is connected to the linear antenna"
When viewed in the opposite direction, the impedance is markedly higher than the impedance on the antenna side.

[0013]

According to the above-described means, a) Since the composite antenna is capacitively coupled to the high frequency circuit, the capacitive coupling is maintained even when the composite antenna is in the intermediate state of extension and storage, so that (2) Since it has a function and does not have a contact part that is capacitively coupled as described above and electrically switches between conduction and insulation, there is no possibility of causing a trouble of conduction due to imperfect contact. ) The composite antenna can be integrally formed of a metal material, and since it does not have a structure in which a plurality of metal members are joined by an insulating material, it has high mechanical strength and excellent durability. Since the antenna is capacitively coupled to the high-frequency circuit, and it is not necessary to provide a conducting part in which the metallic member slides while strongly rubbing, the composite antenna can be smoothly extended and stored, and the operation can be performed. It has a high commercial value because it has a good feeling, and (e) It is not necessary to make contact and conduction between the composite antenna and the contact member fixed to the case, so it is a restriction to attach a waterproof member such as an O-ring. It is suitable for taking a waterproof structure without receiving it. F) As mentioned above, since the composite antenna is capacitively coupled to the high frequency circuit and insulated from the direct current, it has excellent electrostatic withstand voltage. Since the / 2 helical antenna and the λ / 2 linear antenna are connected in series, the antenna operates at 1/2 wavelength both when the antenna is extended and when it is stored. This makes it possible to maximize the gain to the standard.

As described above, the characteristics of (a) to (f) are combined, and as a portable radio telephone antenna, it is possible to exhibit a far superior performance as compared with the prior art.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, referring to FIGS.
An embodiment of the present invention will be described. FIG. 1 shows an embodiment of a connection structure of the present invention configured to carry out a method of connecting a helical top antenna according to the present invention. (A) shows a composite antenna pulled out of a case to make a normal call state. FIG. 6B is a schematic cross-sectional view in the extended posture, and FIG. 9B is a schematic cross-sectional view in the storage posture in which the linear antenna portion of the composite antenna is pushed into the case and the helical antenna portion is projected outside the case. Reference numeral 1 denotes a case in which a circuit board 4 having a high frequency circuit formed therein is installed.
Reference numeral 7 denotes a helical top type composite antenna element, in which a helical antenna 7b having an electric length of λ / 2 is fixed and electrically connected to one end of a linear antenna 7a having an electric length of λ / 2. FIG. 1A illustrates a normal operation state of the mobile wireless phone. Since the figure (B) is in a carrying state,
The vertical and horizontal postures are not fixed. However, for convenience of explanation, the upper part of the posture shown in (A) and the posture shown in (B) are referred to as "upper", and the lower part of the diagram is referred to as "lower". Therefore, the λ / 2 helical antenna 7b has
This means that it is fixed and electrically connected to the upper end of the / 2 wire antenna 7a.

A synthetic resin guide sleeve 8 for slidably supporting the linear antenna 7a in the vertical direction penetrates the top wall of the case 1 and is fixed, and the guide sleeve 8 is waterproof. The O-ring for is attached. The linear antenna 7a of the composite antenna element 7 is closely fitted and inserted into the O-ring, whereby a waterproof function is achieved, and the composite antenna element 7 has an appropriate frictional resistance against vertical sliding. Is given to improve the operation feeling, and the composite antenna element 7 in the expanded state holds its position, and there is no risk of contraction by normal handling unless it is intentionally pushed. Although the composite antenna element 7 moves up and down, it is positioned so as to face the λ / 2 linear antenna 7a over the entire vertical movement stroke thereof, and does not come into contact with the linear antenna to conduct. An exciter 10 that resonates at λ / 4 is installed separately. The λ / 4 exciter 10 of this embodiment is formed in a zigzag shape on the circuit board 4 on which the high frequency circuit of the mobile radio telephone is provided. FIG. 2 is a perspective view schematically showing the above-described embodiment shown in FIG. 1 including the periphery of the portion shown in FIG. However, in order to simplify the drawing, the drawing method is appropriately used. Reference numeral 12 shown in FIG. 2 is a high-frequency unit forming the main body of the wireless device, and a high-frequency circuit covered and hidden by the shield case 14 is formed on the circuit board 4. The high frequency unit 12 is provided on one surface of the circuit board 4.
Although the ground plane 12b is laminated, the ground plane 12b does not cover the front surface of the circuit board 4. In the area where the ground plane 12b is not provided, the λ / 4 exciter 10 is formed as a zigzag conduction pattern. The open end 10a of the λ / 4 exciter 10 faces and is separated from the λ / 2 linear antenna 7a to form an electrostatic coupling capacitance c. Through the above-mentioned coupling capacitance c, the composite antenna element 7 is in the extended state (see FIG. 1A) and the housed state (see FIG. 1B), and in an intermediate state between them. Also, it is electromagnetically connected to the high-frequency unit 12 and functions as an antenna. In particular, the maximum gain is obtained in the expanded state (see FIG. 1A). Further, since the composite antenna element 7 is insulated from the λ / 4 exciter 10 without being electrically connected in terms of direct current, the electrostatic withstand voltage is secured in the basic structure. The value of the coupling capacitance c can be set as desired by design calculation, or can be experimentally measured or can be increased or decreased. By adjusting this value to the critical coupling state, excellent antenna characteristics can be obtained.
Even in the stored state shown in (B), the extended state (A
A gain close to that shown in the figure) is obtained. FIG. 3 is a directional characteristic / gain graph in the antenna connection structure of the above embodiment,
(A) shows the front-back pattern in the vertical plane in the extended posture,
Similarly, (B) shows the front and rear patterns in the vertical plane in the stored posture, respectively. Since it is not necessary to consider transmission / reception in the direct upward direction and the direct downward direction in the mobile radio telephone, considering a direction close to the horizontal direction, it is possible to perform highly sensitive communication at the time of extension shown in FIG. It can be seen that sufficient sensitivity can be obtained for incoming call detection even during storage shown in FIG. When the antenna is pushed into the case gradually, the antenna characteristics deteriorate,
It becomes the worst when it is pushed in about half, but it tends to improve again when pushed further, and it functions as an antenna at all positions. Then, if the radio wave condition is good, the call can be made even in the housed state shown in FIG.

(See FIG. 2) The feeding end 10b of the λ / 4 exciter 10 formed as a zigzag type conduction pattern in the "area where the ground plane 12b is not layered" of the circuit board 4.
Is electrically connected to the output end 12a of the high frequency unit 12 by the microstrip line 13 formed on the "opposite side of the circuit board 4 facing the ground plane 12b". According to the configuration of this embodiment, the λ / 4 exciter 10 and its conductive connection are formed as part of the operation of printing, developing, and fixing the conductive pattern on the circuit board, and the component cost and assembly cost are significantly reduced. It As shown in FIGS. 1A and 1B, align the guide sleeve 8 concentrically,
A metal tube 11 is installed below the metal tube 11 and is housed so that the linear antenna 7a of the composite antenna element 7 does not come into contact with or conduct to the metal tube 11 when the housing posture shown in FIG. The stored λ / 2 wire antenna 7a is the metal tube 1
In this embodiment, an insulating tube 12 made of an electrically insulating material is fitted in the metal tube 11 so as not to come into contact with 1 and conduct electricity. Since the scales of FIGS. 1A and 1B are small, for convenience of reading, the insulating tube 12 is drawn by a broken line to show a schematic shape and position. 4A and 4B show three examples of concrete embodiments for preventing conduction of the linear antenna in the antenna mounting structure according to the present invention, and FIG. 4A is a diagram showing an example of a configuration similar to that of FIG. Sectional view,
(B) is a sectional view of a main part of a similar embodiment, and (C) is a sectional view of a main part of an application example. See FIG. 4 (A). The metal tube 11 is grounded. However, in the present invention, grounding does not mean conducting to the earth's crust, but conducting to the earth circuit of the radio, and means conducting to the ground plane 12b of FIG. 2, for example. The insulating tube 12 is formed of a synthetic resin material, press-fitted and fixed in the metal tube 11, and the wire antenna 7a.
It is slidably fitted to.

See FIG. 4 (B). In this example, the metal tube 11
The inner peripheral surface of is exposed, and the insulating coating 15 is applied to the outer peripheral surface of the linear antenna 7a. Even with this configuration,
It is possible to prevent conduction between the metal tube 11 and the wire antenna 7a without hindering the wire antenna 7a from entering and exiting the metal tube 11. From the same idea, it is conceivable to apply an insulating coating (not shown) to the inner peripheral surface of the metal tube 11, but if the linear antenna 7a is covered as shown in the example of FIG. This is convenient because it is protected from wind and rain in the extended posture that is pulled out of the case. When the length of the metal tube 11 in FIG. 4A is shortened, the metal ring 17 shown in FIG. 4C is obtained. Although it is difficult to clearly define the distinction between a tube and a ring, for convenience of explanation, a tube whose length is shorter than the diameter (outer diameter) is called a ring. However, a conductive tube, a cylinder, or a ring belongs to the technical scope of the present invention.

[0019]

When the present invention is applied, a) Since the composite antenna is capacitively coupled to the high frequency circuit, the capacitive coupling is maintained even when the composite antenna is in the intermediate state of extension and storage, and B) As mentioned above, since there is no contact part that is capacitively coupled as described above and electrically switches between conduction and insulation, there is no fear of causing a trouble of conduction failure due to imperfect contact. , C) The composite antenna can be integrally formed of a metal material, and since it does not have a structure in which a plurality of metal members are joined by an insulating material, it has high mechanical strength and excellent durability. Since the composite antenna is capacitively coupled to the high frequency circuit, and there is no need to provide a conducting part in which the metallic member slides while strongly rubbing, the expansion and storage operation of the composite antenna is smooth. Since the feeling of operation is good, the product value is high. (E) Since it is not necessary to make contact and conduction between the composite antenna and the contact member fixed to the case, it is possible to attach a waterproof member such as an O-ring. It is not restricted and is suitable for a waterproof structure. F) As mentioned above, since the composite antenna is capacitively coupled to the high frequency circuit and insulated from the direct current, it has excellent electrostatic withstand voltage. ) Since the λ / 2 helical antenna and the λ / 2 linear antenna are connected in series, the antenna operates at 1/2 wavelength both when the antenna is extended and when it is stored. This makes it possible to maximize the gain to the standard.

As described above, the characteristics of (a) to (f) are combined, and a practical effect that the performance as a portable radio telephone antenna can be remarkably excellent as compared with the prior art is exhibited.

[Brief description of drawings]

FIG. 1 shows an embodiment of a connection structure of the present invention configured to carry out a method of connecting a helical top antenna according to the present invention. FIG. FIG. 3B is a schematic cross-sectional view in the extended posture, and FIG. 6B is a schematic cross-sectional view in the storage posture in which the linear antenna portion of the composite antenna is pushed into the case and the helical antenna portion is projected outside the case.

FIG. 2 is a perspective view schematically showing the above-described embodiment shown in FIG. 1 including the periphery of the portion shown in FIG. However, in order to simplify the drawing, the drawing method is appropriately used.

3A and 3B are directional characteristics / gain graphs of the antenna connection structure of the above-described embodiment, where FIG. 3A is a front-back pattern in a vertical plane in an extended posture, and FIG. 3B is a front-back pattern in a vertical plane in the stored posture. , Respectively.

FIG. 4 is a view showing three examples of specific examples for preventing conduction of the linear antenna in the antenna mounting structure according to the present invention, in which (A) is an example configured as in FIG. 1 above. FIG. 3B is a cross-sectional view of a main part, FIG. 3B is a cross-sectional view of a main part of a similar embodiment, and FIG.

FIG. 5 shows a known antenna disclosed in Japanese Patent Laid-Open No. 6-196912, (A) is a vertical cross-sectional view schematically illustrating a state in which most of the linear antenna portion is pulled out of the case and extended; (B) is a vertical cross-sectional view schematically illustrating a state in which the linear antenna portion is pushed into the case and housed, and only the helical antenna portion is projected outside the case.

FIG. 6 shows a connection structure of a helical top antenna according to US Pat. No. 5,204,687, (A) schematically showing a state where a linear antenna portion of a composite antenna is pulled out upward, FIG. 6 is a vertical sectional view of (A) of the known example shown in FIG. 5, (B) schematically illustrates a state in which the linear antenna portion is housed in a case, and the housed state of the known example shown in FIG. FIG. 3 is a vertical cross-sectional view corresponding to the part (B) drawn and in which a part is broken.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Case, 2 ... Composite antenna, 2a ... (lambda) / 4 filament antenna, 2b ... (lambda) / 4 helical antenna, 2c ... Lower conducting part, 2d ... Upper conducting part, 3 ... Sleeve-like conducting terminal, 4 ...
Circuit board, 5 ... Ground contact piece, 6 ... Composite antenna, 6a ...
Wire antenna, 6b ... Wire antenna conducting portion, 6c ... λ /
4 helical antenna, 6d ... Helical antenna conducting part,
6e ... Electric insulator, 7 ... Composite antenna according to the present invention, 7
a ... λ / 2 linear antenna, 7b ... λ / 2 helical antenna, 8 ... Guide sleeve, 9 ... O-ring, 10 ... λ / 4
Exciter, 10a ... Open end, 10b ... Feed end, 11 ... Metal tube, 12 ... Radio device main body high frequency unit, 12a ... Radio device main body high frequency unit output end, 12b ... Main plate, 13 ... Microstrip line, 14 ... Shield case , C ... Coupling capacitance.

Claims (23)

[Claims] 1. A method of attaching a helical top type antenna to a case accommodating a high frequency circuit of a radio device to mechanically support the antenna and electrically connecting the antenna to the high frequency circuit, A helical antenna with an electrical length of approximately 1/2 is connected to one end of a linear antenna with an electrical length of approximately 1/2 wavelength, and is mechanically brought into direct contact and electrically connected to form a helical antenna. A top-shaped composite antenna element is formed, the helical antenna is positioned outside the case, the linear antenna is pierced through the wall of the case, and slidably supported. They are made to face each other without being brought into direct mechanical contact with each other, and are not electrically connected to each other, and are electromagnetically coupled via a capacitance. It is characterized by the provision of means for making the impedance significantly higher than the impedance on the antenna side when looking at the opposite direction of "one side where the helical antenna is connected to the linear antenna" from the point where capacitive coupling is performed. , How to connect the helical top antenna. 2. When the composite antenna element is slid in a direction to be pushed into the case, the wire antenna is "not connected to the helical antenna" rather than "where the wire antenna is capacitively coupled to the high frequency circuit". Side '' into a conductive tube or ring and ground the tube or ring so that the impedance on the side not connected to the helical antenna is greater than the impedance on the antenna side. The method of connecting the helical top antenna according to claim 1, further comprising increasing the number of the elements so that the portions are separated from each other in a circuit manner to prevent the influence on the high frequency circuit. 3. The wire antenna according to claim 1 or 2, wherein the linear antenna is opposed to an open end of an exciter installed in a case and having an electrical length of about ¼ wavelength. How to connect the helical top antenna described in. 4. The helical top antenna according to claim 3, wherein a capacitance formed between the linear antenna and an exciter is adjusted to achieve a substantially critical coupling state. How to connect. 5. The helical top according to claim 3, wherein the exciter is formed as a zigzag conduction pattern on a substrate on which the high frequency circuit is formed. How to connect the antenna. 6. A microstrip line is formed on a substrate shared by the exciter and the high-frequency circuit, and the microstrip line serves as a power supply end of the exciter and an output end of a high-frequency circuit of a radio device. 6. The method for connecting a helical top antenna according to claim 5, wherein the connection is conducted. 7. A wire antenna of the composite antenna element is closely attached to an O-ring for insertion, and the O-ring is attached to a wall of the case to be waterproof.
A method of connecting the helical top antenna according to any one of claims 1 to 6. 8. A composite antenna element is obtained by fitting an electrically insulating tubular member into the electrically conductive tube and introducing the filament antenna of the composite antenna element into the electrically insulating tube. 8. The method for connecting a helical top antenna according to claim 2, wherein conduction with the conductive tubular member is prevented. 9. The metal tube when the conductive tube is made of a metal material, and the inner peripheral surface of the metal tube is provided with an electrically insulating coating so that a linear antenna is introduced into the metal tube. And the wire antenna do not come into direct contact,
8. The method for connecting a helical top antenna according to claim 2, wherein conduction between the both is prevented. 10. The wire antenna of the composite antenna element is provided with an electrically insulating and water resistant coating to prevent contact and conduction between the wire antenna and a conductive tube or ring, and 7. The method for connecting a helical top antenna according to claim 2, wherein the linear antenna is protected from rain and dew. 11. When the linear antenna of the composite antenna element is slid in a direction to be pushed into the case, the linear antenna element is guided into a tube made of an electrically insulating material, and
By preliminarily fitting a conductive annular member onto the tube made of the electrically insulating material, the linear antenna is allowed to enter the annular member without contacting or conducting with the annular member. A method of connecting the helical top antenna according to any one of claims 2 to 6. 12. A structure in which a helical top type antenna is attached to a case accommodating a high frequency circuit of a radio device to mechanically support the antenna and electrically connect the antenna to the high frequency circuit, A helical top type composite antenna element is formed by connecting a helical antenna having an electric length of about 1/2 to one end of a linear antenna having an electric length of about 1/2 wavelength. With the helical antenna positioned outside the case, the linear antenna is slidably supported through the wall of the case, and the linear antenna is not mechanically directly contacted with the high frequency circuit. , Where they face each other without being electrically conducted, are electromagnetically coupled through a capacitance, and where the linear antenna is capacitively coupled to a high frequency circuit, A connection structure for a helical top antenna, characterized in that when viewed in the opposite direction of "one side in which the helical antenna is connected to the linear antenna", the impedance is significantly higher than the impedance on the antenna side. . 13. When the helical antenna of the composite antenna element is directed upward and the linear antenna is placed in a substantially vertical posture, the conductive antenna is grounded or is grounded concentrically with the linear antenna. A conductive annular member is provided, and when the linear antenna slides vertically with respect to the case, the linear antenna is configured to move in and out of the internal space of the tubular member or the annular member. The connection structure for a helical top antenna according to claim 12. 14. An exciter tuned at about 1/4 wavelength is fixed in the case, and the linear antenna faces the exciter without contact or conduction. The helical top antenna connection structure according to claim 12 or 13. 15. The helical structure according to claim 14, wherein the linear antenna is substantially critically coupled to the open end of the exciter via an electrostatic capacitance. Top antenna connection structure. 16. A zigzag conduction pattern having an electrical length of about ⅛ wavelength is formed on the circuit board on which the high frequency circuit is formed so as to function as an exciter. The helical top antenna connection structure according to claim 14 or 15, characterized in that. 17. A microstrip line formed on the circuit board, wherein a feeding end of the exciter having the zigzag-shaped conduction pattern is electrically connected to an output end of the high frequency circuit. The connection structure for a helical top antenna according to claim 16. 18. A guide sleeve is fixed through the wall of the case, and an O-ring is held by the guide sleeve, and the linear antenna of the composite antenna element is inserted into the O-ring. The helical top antenna connection structure according to any one of claims 12 to 17, wherein the connection structure is the same as that of the first embodiment. 19. The filament antenna of the composite antenna element is vertically supported by a guide sleeve with the helical antenna upward, and the filament antenna is concentric with the guide sleeve below the guide sleeve. The helical top antenna according to claim 18, wherein a metal tube having an inner diameter larger than an outer diameter of the antenna is fixed to the case and electrically connected to the ground of the high frequency circuit. Connection structure. 20. A tubular member made of an electrically insulating material that is loosely fitted to the linear antenna is inserted into the metal tube and fixed to the metal tube. 20. The helical top antenna connection structure according to claim 19, wherein the upper end of the electrically insulating tubular member is located above the upper end of the metal tube. 21. An electrically insulative coating is applied to the inner peripheral surface of the metal tube so that both members are not electrically conducted when the linear antenna enters the metal tube. 20. The connection structure for a helical top antenna according to claim 19, wherein: 22. A coating having electrical insulation and water resistance is applied to the filament antenna, and when the filament antenna descends and enters the metal tube, conduction with the metal tube is prevented. 20. The helical top antenna according to claim 19, wherein the linear antenna is designed to be waterproof against rain and dew when the linear antenna rises and is located outside the case. Connection structure. 23. In a state where the linear antenna of the composite antenna element is vertically supported by a guide sleeve with the helical antenna facing upward, a linear filament is provided below the guide sleeve and concentrically with the guide sleeve. A tube made of an electrically insulating material having an inner diameter larger than the outer diameter of the antenna is fixed to the case, and an electrically conductive material annular member is externally fitted to the electrically insulating tube, When the filament antenna descends,
The helical top antenna connection structure according to claim 18, wherein the connection structure is configured to be guided by the electrically insulating tube to enter into the conductive annular member.