Antenna device and method for manufacturing the same

Abstract
Relating to an antenna device used in wireless unit for mobile communication or the like, it is an object to present an antenna device hardly causing uneven pitch or deformation of antenna elements, high in gain and reliability, excellent in productivity, and having two or more impedance characteristics, and a method of manufacturing the same. Both ends of plural bands (16) are alternately connected consecutively, both ends of plural bands (18) are alternately connected consecutively in a first antenna element (11) made of a thin metal plate of nearly circular spiral form projecting alternately in the longitudinal direction, a second antenna element (12) made of a thin metal plate formed by projecting in a nearly semicircular tubular form in the front direction is disposed at a nearly concentrical position, a mounting bracket (13) is connected to one end of the first antenna element (11), and the outer circumference of the members is covered with a cover (15) made of an insulating resin, thereby composing an antenna device.
Description




TECHNICAL FIELD




The present invention relates to an antenna device mainly used in wireless unit for mobile communication or the like, and a method of manufacturing the same.




BACKGROUND ART




Recently there is a rapidly increasing demand for wireless unit for mobile communication such as cellular phone. The wireless unit is diversified in function so as to transmit and receive more information by one unit. To meet such demand for multiple functions, a wireless unit capable of transmitting and receiving radio waves in plural frequency bands is developed. To cope with plural frequencies, the wireless unit has an antenna setting two or more impedance characteristics.




As the antenna applicable to plural frequency bands, the helical antenna with coil winding is widely used.




A conventional antenna is explained by referring to FIG.


28


.





FIG. 28

is a sectional view of a conventional antenna device applicable to two frequency bands. As shown in

FIG. 28

, a conventional antenna device


6


comprises:




a) a first helical antenna element (HAE)


1


made of copper wire or copper alloy wire,




b) a second HAE


4


made of copper wire or copper alloy wire,




c) a core


3


made of insulating resin for winding the HAE


1


and HAE


4


while insulating the HAE


1


and HAE


4


,




d) a mounting bracket


2


made of metal for mounting the core


3


on which the HAE


1


and HAE


4


are wound, and further mounting on the wireless unit, and




e) an insulating cover


5


for covering the outer circumference of the HAE


1


, HAE


4


, and core


3


.




The HAE


1


includes an upward coil winding


1


A, and a junction


1


B for electrically connecting to the mounting bracket


2


. The mounting bracket


2


has a circular recess


2


A for fitting the lower end of the core


3


. The winding


1


A of the HAE


1


is wound around the core


3


which is fixed to the recess


2


A. The junction


1


B at the lower end of the HAE


1


is electrically connected to the recess


2


A of the mounting bracket


2


. The winding diameter and winding pitch of the HAE


1


are same as the winding diameter and winding pitch of the HAE


4


. In the winding pitch of the winding


1


A of the HAE


1


, the HAE


4


is wound. As a result, the HAE


1


and HAE


4


are mutually insulated. The HAE


4


is parasitic, and is insulated from the mounting bracket


2


. An insulating cover


5


is formed by insert molding of insulating resin on the outer circumference of the core


3


on which the HAE


1


and HAE


4


are wound.




In the antenna device


6


thus composed, when sending and receiving radio waves, an electric current is induced between the windings of the HAE


1


and HAE


4


by electromagnetic inductive action. Making use of the induced current, the wireless unit having the antenna


6


can send and receive radio waves in at least two frequency bands.




The configuration of the HAE


1


and parasitic HA


4


requires high precision so as not to contact with each other and to maintain the desired antenna characteristic. In the conventional antenna


6


, however, the winding may be uneven in pitch or may be deformed when winding the copper wire or copper alloy wire on the core


3


and covering with the insulating resin


5


. Therefore, in the conventional antenna device having such structure, it is hard to obtain an impedance characteristic corresponding to a desired frequency band. That is, in the gain of the conventional antenna device, fluctuations were large. Accordingly, in order to obtain an antenna having a desired characteristic, it was necessary to sort out. There was also a limit for enhancing the yield of the conventional antenna device. In the conventional antenna device, therefore, reduction of cost was limited by the sorting process and the yield.




SUMMARY OF THE INVENTION




The invention relates to an antenna device having two or more impedance characteristics capable of solving the problems of the conventional antenna device. It is hence an object of the invention to present an antenna device hardly causing uneven pitch or deformation of antenna elements, stable in gain, and high in reliability. It is also an object of the invention to present a method of manufacturing antenna devices excellent in productivity.




To achieve the object, the antenna device of the invention comprises:




a) a first antenna element (FAE) of spiral form having nearly parallel plural bands formed so that both ends may be connected alternately and consecutively, and formed so that at least one or more bands may be projected,




b) a second antenna element (SAE) of meandering form having nearly parallel plural bands formed so that both ends may be connected alternately and consecutively, and formed so that at least one or more bands may be projected,




c) a core made of an insulating resin for disposing the FAE and SAE nearly at concentrical positions,




d) a mounting bracket connected to one end of the FAE, and




e) a cover made of an insulating resin for covering the outer circumference of each member, by exposing a part of the mounting bracket.




The FAE and SAE are formed by pressing a conductive thin metal plate punched in a specified shape into a desired shape. In order that the FAE and SAE may be mutually insulated, each inner side is fixed to the core. One end of the FAE is electrically connected to the mounting bracket. The mounting bracket has a threaded portion for mounting on a wireless unit for mobile communication such as cellular phone. The threaded portion is exposed.




Thus is presented an antenna device hardly causing uneven pitch or deformation of the antenna elements during manufacture, and having two or more impedance characteristics. It is high in reliability because uneven pitch or deformation hardly occurs.




Moreover, the antenna device having such structure can be produced easily, and the product yield is high.




The invention also provides a method of manufacturing antenna device which comprises:




a) a step of forming a first element plate by a step of punching a conductive thin metal plate of a specified dimension, and a step of pressing a part of the punched thin metal plate,




b) a step of forming a second element plate by a step of punching a conductive thin metal plate of a nearly same dimension as the first element plate, and a step of pressing a part of the punched thin metal plate,




c) a step of stacking up the outer circumferential parts of the first element plate and second element plate in the thickness direction,




d) a step of primary insert molding of a resin dielectric element for forming a core having a plurality of resin support parts by fixing the pressed portion of the stacked first element plate and the pressed portion of the second element plate,




e) a step of separating the core from the outer circumference by cutting off the flat outer circumferential parts of the pressed portion of the first element plate and the pressed portion of the second element plate near the core, and




f) a step of secondary insert molding of a resin dielectric element for forming a cover for covering the outer circumference by holding the resin support parts.




In the step of forming the first element plate of the invention,




a conductive thin metal plate of a specified dimension is blanked, and nearly parallel plural rectangular holes of same length are provided so that both ends may be convex and concave alternately, thereby forming plural linear portions,




one side of convex and concave portion of the plural rectangular holes is separated from the outer circumferential part in a linked state,




a band is formed by pressing at least a part of the linear portion of the plural linear portions,




the band is formed so as to be coupled to the outer circumference at the other side, and




a mounting bracket is connected and fixed to one end of the band, thereby forming a first element plate.




In the step of forming the second element plate of the invention,




a conductive thin metal plate is blanked, and nearly parallel plural hook holes of same length are provided alternately in reverse directions, so that plural linear portions are linked in a thin linkage alternately right and left,




one side of the plural hook holes is separated from an outer frame in a linked state,




a band is formed by pressing at least a part of linear portion of the plural linear portions, and




other side of the band is coupled to the outer circumference, thereby forming a second element plate.




In the primary insert molding step of the invention,




outer circumferential parts of the first element plate and second element plate are held,




an insulating resin is processed by insert molding,




the band of the first element plate and the band of the second element plate are fixed by resin from the inner side by this insert molding,




the mounting bracket is coupled, and




a core having a plurality of resin support parts projecting by a specified dimension from the outer circumference of the band of the first element plate and the band of the second element plate is formed.




In the step of separating the core from the outer circumference of the invention,




the core is separated from the outer circumference by cutting off near the core coupled to the outer circumference of the first element plate and second element plate, and the convex and concave linked portion at the end of the plural slots and the thin linkage are separated.




By this separation, an FAE is formed from the first element plate and an SAE is formed from the second element plate.




In the step of secondary insert molding of a resin dielectric element of the invention,




the FAE and SAE formed in the above step, and the core are molded and processed by an insulating resin, while holding the mounting bracket and the resin support parts, and




a part of the mounting bracket is exposed, and a cover for covering the outer circumference of the FAE and SAE is formed.




In the antenna device by the manufacturing method of the invention, uneven pitch or deformation of antenna elements hardly occur during manufacture, and the antenna device having two or more impedance characteristics is obtained. Moreover, since uneven pitch or deformation hardly occurs, the reliability is high.




According to the manufacturing method of the invention, the antenna device can be produced easily, and the product yield is high.




The antenna device of the invention can be used in wireless unit for mobile communication or the like, personal computer, transceiver, professional communication for example, taxi, fishing boat, police), and other wireless unit for wireless communication.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a perspective view of partial section of an antenna device according to a first embodiment of the invention.





FIG. 2A

is a front view of a first antenna element of he antenna device in FIG.


1


.





FIG. 2B

is a perspective view of the first antenna element of the antenna device in FIG.


1


.





FIG. 3A

is a front view of a second antenna element of the antenna device in FIG.


1


.





FIG. 3B

is a perspective view of the second antenna element of the antenna device in FIG.


1


.





FIG. 4A

is a front view of the antenna element of the antenna device in FIG.


1


.





FIG. 4B

is a perspective view of the antenna element of the antenna device in FIG.


1


.





FIG. 5A

is a top view of the first antenna element shown in

FIGS. 2A

,


2


B.





FIG. 5B

is a top view of the second antenna element shown in

FIGS. 3A

,


3


B.





FIG. 5C

is a top view showing the combined structure of the first antenna element shown in FIG.


5


A and the second antenna element shown in FIG.


5


B.





FIG. 6

is a perspective view of a first antenna element of a second antenna device.





FIG. 7

is a perspective view of a second antenna element of the second antenna device.





FIG. 8

is a perspective view of an antenna element combining the first antenna element and second antenna element of the second antenna device.





FIG. 9A

is a top view of the first antenna element of the second antenna device.





FIG. 9B

is a top view of the second antenna element of the second antenna device.





FIG. 9C

is a top view of the antenna element of the second antenna device.





FIG. 10

is a perspective view of a first antenna element of a third antenna device.





FIG. 11

is a perspective view of a second antenna element of the third antenna device.





FIG. 12

is a perspective view of an antenna element combining the first antenna element and second antenna element of the third antenna device.





FIG. 13A

is a top view of the first antenna element of the third antenna device.





FIG. 13B

is a top view of the second antenna element of the third antenna device.





FIG. 13C

is a top view of the antenna element of the third antenna device.





FIG. 14

is a perspective view of a first antenna element of a fourth antenna device.





FIG. 15

is a perspective view of a second antenna element of the fourth antenna device.





FIG. 16

is a perspective view of an antenna element combining the first antenna element and second antenna element of the fourth antenna device.





FIG. 17A

is a top view of the first antenna element of the fourth antenna device.





FIG. 17B

is a top view of the second antenna element of the fourth antenna device.





FIG. 17C

is a top view of the antenna element of the fourth antenna device.





FIG. 18

is a perspective view of a first antenna element of a fifth antenna device.





FIG. 19

is a perspective view of a second antenna element of the fifth antenna device.





FIG. 20

is a perspective view of an antenna element combining the first antenna element and second antenna element of the fifth antenna device.





FIG. 21A

is a top view of the first antenna element of the fifth antenna device.





FIG. 21B

is a top view of the second antenna element of the fifth antenna device.





FIG. 21C

is a top view of the antenna element of the fifth antenna device.





FIG. 22

is a perspective view explaining a forming method of a first element plate in a manufacturing method of antenna device according to a second embodiment of the invention.





FIG. 23

is a perspective view explaining a forming method of a second element plate of the antenna device in FIG.


22


.





FIG. 24

is a perspective view showing a combined state of the first element plate and second element plate of the antenna device in FIG.


22


.





FIG. 25

is a perspective view showing a state after primary insert molding process of the antenna device in FIG.


22


.





FIG. 26

is a perspective view of a core with a mounting bracket of the antenna device in FIG.


22


.





FIG. 27

is a perspective view showing a state after secondary insert molding process of the antenna device in FIG.


22


.





FIG. 28

is a sectional view of a conventional antenna device.











BEST MODE FOR CARRYING OUT THE INVENTION




Referring now to the drawings, preferred embodiments of the invention are described in detail below.




Embodiment 1





FIG. 1

is a perspective view of partial section o an antenna device according to a first embodiment of the invention.




The antenna device shown in

FIG. 1

comprises:




a) an FAE


11


formed in a nearly circular spiral form by punching and pressing a thin metal plate,




b) an SAE


12


as a parasitic antenna element formed in a nearly semicircular tubular form by punching and pressing a thin metal plate,




c) a mounting bracket


13


for connecting and fixing one terminal end


11


A of the FAE


11


(see

FIGS. 2A

or


2


B),




d) a core


14


made of an insulating material coupled with the mounting bracket


13


, for fixing the FAE


11


and SAE


12


in a mutually insulating state at nearly concentrical positions, and




e) a cover


15


made of an insulating material cove ring the outer circumference of the FAE


11


and SAE


12


, by exposing the vicinity of a threaded portion


13


A of the mounting bracket


13


.




As a thin metal plate for forming the FAE and SAE, a conductive copper plate or copper alloy plate, or a conductive aluminum plate or aluminum alloy plate is suited. But any other metal may be used as far as it is conductive.




The mounting bracket


13


has a threaded portion


13


A on its outer circumference for mounting this antenna device on a wireless unit to be used.




The detailed shape of the FAE


11


is shown in a front view in FIG.


2


A and in a perspective view in FIG.


2


B. The FAE


11


is formed by blanking a thin metal plate.




In the FAE


11


, being made of a thin metal plate,




a terminal end


11


A of the FAE


11


connected to the mounting bracket


13


,




plural junctions


17


B,




plural bands


16


A projecting in a nearly semicircular form in the front direction,




plural junctions


17


A, and




plural bands


16


B projecting in a nearly semicircular form in the rear direction




are formed continuously in a nearly spiral form as shown in the front view in FIG.


2


A. The terminal end


11


A, plural bands


16


A, and plural bands


16


B are formed nearly parallel to each other as seen from the front side as shown in FIG.


2


A. The width WA of the bands


16


A and bands


16


B is nearly equal. The interval WB of the adjacent band


16


A and band


16


B is larger than the width WA of the band. The plural junctions


17


B and plural junctions


17


A are formed nearly parallel to each other as seen from the front side as shown in FIG.


2


A.




Further, as shown in

FIG. 2B

, the plural bands


16


B are processed in a nearly semicircular form to project to the inner depth, and the plural bands


16


A are processed in a nearly semicircular form to project to the front side. As shown in

FIG. 2B

, the FAE


11


is formed, on the whole, in a nearly circular spiral form.




The detailed shape of the SAE


12


is shown in a front view in FIG.


3


A and in a perspective view in FIG.


3


B. The SAE


12


is formed by blanking a thin metal plate.




In the SAE


12


, being made of a thin metal plate,




plural junctions


19


A,




plural bands


18


projecting in a nearly semicircular form, and




plural junctions


19


B




are formed continuously in a nearly meandering form as shown in the front view in FIG.


3


A. The plural bands


18


are formed nearly parallel to each other as seen from the front side as shown in FIG.


3


A. The width WC of the bands


18


is nearly equal to or narrower than the width WA of the bands of the FAE


11


. Supposing the interval of the mutually adjacent band


18


to be WD, the following relation is established.








WA+WB≈WC+WD








The plural junctions


19


A and plural junctions


19


B are formed nearly parallel to each other as seen from the front side as shown in FIG.


3


A.




Further, as shown in

FIG. 3B

, the plural bands


18


are processed in a nearly semicircular form to project to the front direction. The radius of the nearly semicircular form of the plural bands


18


is processed to be nearly same as the radius of the nearly circular spiral form of the FAE


11


. The arc shape of the first antenna element


11


and second antenna element


12


is described later.




The configuration of the FAE


11


and SAE


12


mounted on the mounting bracket


13


is shown in a front view of the antenna element in FIG.


4


A and in a perspective view in FIG.


4


B. As shown in FIG.


4


A and

FIG. 4B

, the bands


18


of the SAE


12


are combined to enter parallel while keeping an insulating state, among the plural bands


16


A of the FAE


11


.




The interval of a certain band


16


A and its adjacent band


16


A in the FAE


11


is






WA+2WB.






The total dimension of a certain band


18


and its adjacent band


18


of the SAE


12


to be inserted in this interval is






2WC+WD.






Hence, as mentioned above, WA+WB≈WC+WD,




Further, since WA<WB, and WA>WC, it follows that






WA+2WB>2WC+WD.






Therefore, the FAE


11


and SAE


12


are kept insulated from each other.




Positioning the junctions


17


A,


17


B, and


19


A,


19


B, the FAE


11


and SAE


12


are combined so as to keep an insulated state. As shown in

FIG. 1

, the FAE


11


and SAE


12


are supported by a core


14


made of an insulating resin. The outer circumference of the FAE


11


and SAE


12


is fixed by a cover


15


made of an insulating resin.




The core


14


and cover


15


are made of a same insulating resin. The core


14


and cover


15


are processed and formed in individual steps. Since the materials are the same, the adhesion of the core


14


and cover


15


is favorable. The level of thermal expansion of the core


14


and cover


15


is also identical. Therefore, the effect is very small due to temperature changes when using the antenna device, and the strength and other mechanical characteristics of the antenna device are stable.




A configuration of combination for maintaining the insulated state of the FAE


11


and SAE


12


is explained below.





FIG. 5A

is a top view of the FAE


11


.

FIG. 5B

is a top view of the SAE


12


.

FIG. 5C

is a top view showing a combined structure of FAE


11


and SAE


12


.




As shown in

FIG. 5A

, a top view of a shape enclosed by the band


16


A, junction


17


A, band


17


B, and junction


17


B of the FAE


11


is an oval form. That is, the both sides of a circle (indicated by dotted line in

FIG. 5A

) formed by the arc of the band


16


A and the arc of the band


16


B are cut off in width C. As shown in

FIG. 5B

, a top view of a shape enclosed by the junction


19


A, band


18


, and junction


19


B of the SAE


12


is nearly semicircular. It is, however, slightly smaller (dimension d in

FIG. 5B

) than the semicircle of the circle (indicated by dotted line in

FIG. 5B

) formed at the radius of the arc of the band


18


. The radius of the arc of the band


16


A, the arc of the band


16


B, and the arc of the band


18


is nearly equal.




The relation between the width C shown in FIG.


5


A and the width D shown in

FIG. 5B

is as follows:






C<D







FIG. 5C

is a top view showing a combined structure of the FAE


11


shown in FIG.


5


A and the SAE


12


shown in FIG.


5


B. When composed as shown in

FIG. 5C

, the band


16


A of the FAE


11


and the junctions


19


A,


19


B of the SAE


12


do not contact with each other, and an insulated state is maintained.




The antenna device of the embodiment has such structure, and the operation of this antenna device is explained below.




The antenna device shown in

FIG. 1

is fixed at a specified position of a wireless unit by means of the threaded portion


13


A formed on the outer circumference of the mounting bracket


13


. A radio frequency signal corresponding to the radio wave sent and received by the antenna device is transmitted between the electric circuit of the wireless unit and the antenna device through the mounting bracket


13


. The FAE


11


set at a specified electric length operates electrically by matching with a first frequency band. The SAE


12


set at a different electric length operates electrically by matching with a second frequency band.




The FAE


11


has an inductance L


1


. There is a floating capacity C


1


between the mutual plural bands (


16


A,


16


B) of the FAE


11


, and between plural bands (


16


A,


16


B) of the FAE


11


and the band


18


of the SAE


12


. The electric length determined by the inductance L


1


and floating capacity C


1


matches with the radio frequency signal of the first frequency band. By this matching, the FAE


11


is set so as to have an impedance characteristic capable of sending and receiving radio wave of the first frequency band most efficiently.




The SAE


12


has an inductance L


2


. There is a floating capacity C


2


between the mutual plural bands


18


of the SAE


12


, and between plural bands


18


of the SAE


12


and the bands (


16


A,


16


B) of the FAE


11


. The electric length determined by the inductance L


2


and floating capacity C


2


matches with the radio frequency signal of the second frequency band. By this matching, the SAE


12


is set so as to have an impedance characteristic capable of sending and receiving radio wave of the second frequency band most efficiently.




The radio frequency signal of the first frequency band is directly transmitted to the electric circuit of the wireless unit from the FAE


11


through the mounting bracket


13


connected to the FAE


11


. The radio frequency signal of the second frequency band is transmitted to the electric circuit of the wireless unit from the SAE


12


, by making use of the capacitive coupling and electromagnetic induction coupling between the FAE


11


and SAE


12


.




Thus, according to the embodiment, the antenna elements are formed by blanking and pressing a thin metal plate. Therefore, the antenna device of the embodiment is mostly free from uneven pitch or deformation of antenna elements, and is easy in assembly and inexpensive.




The electric length of the antenna element is a function of the product of the inductance of the antenna element, and the floating capacity of the antenna element itself and its peripheral parts. Generally, the inductance of the antenna element is a function of the length of the antenna element. In the antenna elements of the embodiment, since a thin metal plate is used, the floating capacity is large. Therefore, the inductance of antenna elements of the embodiment can be set smaller. That is, in the antenna elements of the embodiment, the same electric length is realized by the antenna element of a shorter length.




Therefore, the antenna device of the invention is small in size, light in weight, and high in gain and reliability.




Methods of adjusting the electric length of the FAE


11


or SAE


12


are explained below. This adjustment is intended to obtain an impedance characteristic corresponding to the frequency band.




In a first adjusting method, a part of the bands (


16


A,


16


B) of the FAE


11


or the band


18


of the SAE


12


, or an extension for adjustment provided preliminarily is cut off. By this adjustment, an impedance characteristic corresponding to the intended frequency band is obtained.




In a second adjusting method, a second strip


18


projecting ahead of the SAE


12


is inclined by a specified angle. This specified angle is an angle corresponding to a first strip


16


A projecting ahead of the FAE


11


.




Further, by using a plurality of SAEs


12


, the FAE


11


and SAE


12


can be set at a desired electric coupling degree. For example, the SAE


12


shown in

FIG. 3B

may be cut into upper and lower halves. That is, plural SAEs are provided for the FAE. In this constitution, between the plural SAEs mutually, and at plural positions between them and the FAE


11


, it is possible to set and adjust to a desired electric coupling degree. Accordingly, the impedance characteristic of the antenna device can be controlled easily, and the antenna device is easily applicable to a wide band.




The shape of first antenna element and second antenna element in other example of antenna device of the invention is described below.




The configuration of the second antenna device is shown in

FIG. 6

to FIG.


9


. Only characteristic parts different from the first antenna device are described below. The difference between the second antenna device and the first antenna device lies in the shape of the first antenna element. Other structure is identical except for the parts varying in relation to this difference.





FIG. 6

is a perspective view of a first antenna element


111


of the second antenna device. As shown in

FIG. 6

, a band


116


B of FAE


111


is pressed in a nearly semicircular formal while a band


116


A is flat. That is, the band


116


A is not processed by projection. Shaping as shown in

FIG. 6

, the thickness of the band


116


B is less than the initial thickness owing to the projection process of the band


116


B.




As shown in

FIG. 7

, the shape of a second antenna element


112


of the second antenna device is same as that of the second antenna element


12


of the first antenna device.

FIG. 8

is a perspective view of the antenna element combining the first antenna element


111


and second antenna element


112


of the second antenna device.

FIG. 9A

is a top view of the first antenna element


111


of the second antenna device.

FIG. 9B

is a top view of the second antenna element


112


of the second antenna device.

FIG. 9C

is a top view of the antenna element of the second antenna device.




In the second antenna device, too, the relation of the width WA, interval WB, width WC, and interval WD is same as defined in the first antenna device.




In the second antenna device, nearly same effects as in the first antenna device are obtained.




The configuration of a third antenna device is shown in

FIG. 10

to FIG.


13


. Only characteristic parts different from the first antenna device are described below. The difference between the third antenna device and the first antenna device lies in the shape of the first antenna element. Other structure is identical except for the parts varying in relation to this difference.





FIG. 10

is a perspective view of a first antenna element


211


of the third antenna device. As shown in

FIG. 10

, a band


216


A of FAE


211


is pressed in a nearly semicircular form, while a band


216


B is flat. That is, the band


216


B is not processed by projection. Shaping as shown in

FIG. 10

, the thickness of the band


216


A is less than the initial thickness owing to the projection process of the band


216


A.




As shown in

FIG. 11

, the shape of a second antenna element


212


of the third antenna device is same as that of the second antenna element


12


of the first antenna device.

FIG. 12

is a perspective view of the antenna element combining the first antenna element


211


and second antenna element


212


of the third antenna device.

FIG. 13A

is a top view of the first antenna element


211


of the third antenna device.

FIG. 13B

is a top view of the second antenna element


212


of the third antenna device.

FIG. 13C

is a top view of the antenna element of the third antenna device.




In the third antenna device, too, the relation of the width WA, interval WB, width WC, and interval WD is same as defined in the first antenna device.




In the third antenna device, nearly same effects as in the first antenna device are obtained.




The configuration of a fourth antenna device is shown in

FIG. 14

to FIG.


17


. Only characteristic parts different from the first antenna device are described below. The difference between the fourth antenna device and the first antenna device lies in the shape of the first antenna element and second antenna element. Other structure is identical except for the parts varying in relation to this difference.





FIG. 14

is a perspective view of a first antenna element


311


of the fourth antenna device. As shown in

FIG. 14

, a band


316


A of FAE


311


is pressed in a nearly trapezoidal form, while a band


316


B is flat. That is, the band


316


B is not processed by projection. Shaping as shown in

FIG. 14

, the thickness of the band


316


A is less than the initial thickness owing to the projection process of the band


316


A.





FIG. 15

is a perspective view of a second antenna element


312


of the fourth antenna device. As shown in

FIG. 15

, a band


318


of the SAE


312


is pressed in a nearly trapezoidal form.

FIG. 16

is a perspective view of the antenna element combining the first antenna element and second antenna element of the fourth antenna device.

FIG. 17A

is a top view of the first antenna element


311


of the fourth antenna device.

FIG. 17B

is a top view of the second antenna element


312


of the fourth antenna device.

FIG. 17C

is a top view of the antenna element of the fourth antenna device.




In the fourth antenna device, too, the relation of the width WA, interval WB, width WC, and interval WD is same as defined in the first antenna device.




In the fourth antenna device, nearly same effects as in the first antenna device are obtained.




The configuration of a fifth antenna device is shown in

FIG. 18

to FIG.


21


. Only characteristic parts different from the first antenna device are described below. The difference between the fifth antenna device and the first antenna device lies in the shape of the first antenna element and second antenna element. Other structure is identical except for the parts varying in relation to this difference.





FIG. 18

is a perspective view of a first antenna element of the fifth antenna device. As shown in

FIG. 18

, a band


416


A of FAE


411


is pressed in a nearly trapezoidal form, projecting toward the front side, while a band


416


B is pressed in a nearly trapezoidal form, projecting toward the rear side.





FIG. 19

is a perspective view of a second antenna element


412


of the fifth antenna device. As shown in

FIG. 19

, a band


418


of the SAE


412


is pressed in a nearly rectangular form.

FIG. 20

is a perspective view of the antenna element combining the first antenna element


411


and second antenna element


412


of the fifth antenna device.

FIG. 21A

is a top view of the first antenna element


411


of the fifth antenna device.

FIG. 21B

is a top view of the second antenna element


412


of the fifth antenna device.

FIG. 21C

is a top view of the antenna element of the fifth antenna device.




In the fifth antenna device, too, the relation of t he width WA, interval WB, width WC, and interval WD is same as defined in the first antenna device.




In the fifth antenna device, nearly same effects as in the first antenna device are obtained.




Meanwhile, the first antenna element and second antenna element used in the antenna device are not limited to those shown in the first to fifth antenna devices alone. For example, the first antenna elements and second antenna elements of the first to fifth antenna devices may be used in combination. Further, other first antenna element and second antenna element conforming to the scope of the invention may be used, for example, both may be formed in square, or triangular, pentagonal or other polygonal shapes may be combined. Alternatively, one terminal end of the FAE may be formed in a shape to be connected electrically and mechanically to a specified position of a wireless unit directly, and the mounting bracket may be formed integrally.




Embodiment 2




A manufacturing method of antenna device according to a second embodiment of the invention is described below while referring to

FIG. 22

to FIG.


26


.





FIGS. 22A

,


22


B,


22


C are perspective views explaining the forming method of a first antenna element plate. First, as shown in

FIG. 22A

, nearly parallel rectangular holes


22


of same length are punched and processed in a conductive thin metal plate


21


of a specified dimension. The plural rectangular holes


22


are formed in a convex and concave shape by shifting both ends alternately by dimension D. By this processing, plural linear portions


23


are formed between the adjacent rectangular holes


22


. The linear portions


23


correspond to the bands (for example,


16


A and


16


B) in embodiment 1. In a later process, an opening hole


40


is formed for mounting the mounting bracket


13


. Two bumps


27


for mounting the mounting bracket


13


are formed in the linear portion


23


B between the rectangular hole


22


and opening hole


40


at the lowest end.




Consequently, as shown in

FIG. 22B

, one side


24


A of the convex and concave shape of the plural rectangular holes


22


is cut off from the outer circumference in a linked state. After cutting off the side


24


A, the plural linear portions


23


are processed to project in a nearly semicircular form alternately in the longitudinal direction. However, the linear portion


23


B at the lowest end is not processed. Herein, as shown in

FIG. 22B

, the linear portion


23


projecting in the front direction on the sheet of paper is supposed to be band


25


A, and the linear portion


23


projecting in the rear direction on the sheet of paper is supposed to be band


25


B. In this projecting state, each end of the bands


25


A,


25


B remains connected to the thin metal plate


21


. Other ends of the bands


25


A,


25


B are coupled to the outer circumference by way of the side


24


A. Next, as shown in

FIG. 22C

, the mounting bracket


13


is connected and fixed by crimping to two bumps


27


of the linear portion


23


B at the lowest end. Hereinafter, by blanking and processing the thin metal plate


21


, the mounting bracket


13


is fixed, and a first antenna element plate


26


is obtained.




Similarly,

FIGS. 23A

,


23


B are perspective views explaining the forming method of a second antenna element plate. First, as shown in

FIG. 23A

, a thin metal plate


28


of a nearly same dimension as the first antenna element plate


26


is blanked. It is blanked nearly parallel so that plural hook holes


29


of same length may be formed alternately in reverse directions. Plural linear portions


30


are formed between the adjacent hook holes


29


. The plural linear portions


30


are blanked in a form linked alternately right and left by means of a linkage


31


.




Consequently, as shown in

FIG. 23B

, one side


32


A of the plural hook holes


29


is cut off from the outer circumference in a linked state. After cutting off, the plural linear portions


30


are processed to project in a nearly semicircular form in the front direction. The radius of the nearly semicircular form is nearly same as that of the bands (


25


A,


25


B) of the first antenna element plate


26


. Herein, as shown in

FIG. 23B

, the linear portion


30


projecting in the front direction on the sheet of paper is supposed to be band


33


. The band


33


of a nearly semicircular tubular form is coupled to other side


32


B through a linkage


38


. Hereinafter, by blanking and processing the thin metal plate


28


as shown in

FIG. 23B

, a second antenna element plate


34


is obtained.




Then, as shown in a perspective view in

FIG. 24

, outer circumferential parts of the first antenna element plate


26


and second antenna element plate


34


are overlaid. As a result, between the upward projecting bands


25


A of the first strips


25


, upward projecting bands


33


are combined by entering parallel. Further, holding the outer circumference by the molding die, an insulating resin is processed by primary insert molding. Thus, as shown in a perspective view in

FIG. 25

, the band


25


(not shown) of the first element plate


26


and the band


33


(not shown) of the second element plate


34


are fixed from the inner side by means of the insulating resin. Still more, by this insert molding, the mounting bracket


13


is also coupled and fixed. By this insert molding, a core


36


having four resin support parts


35


projecting by a specified dimension from the outer circumference of the band


25


and band


33


is formed.




As shown in a perspective view in

FIG. 26

, moreover, linkages


37


and


38


overlapping and projecting on the outer circumference of the core


36


are cut off near the outer circumference of the core


36


. The projecting dimension of the cut-off linkages


37


and


38


from the core


36


is set so as to be smaller than the projecting dimension of the resin support parts


35


. This state is shown in

FIG. 26

, and the core with mounting bracket


39


is obtained. By this cutting, the core with mounting bracket


39


is separated from the outer circumference of the first element plate


26


and second element plate


34


.




At this time, the narrow linkage


31


of the linked portion of convex and concave ends of rectangular holes


22


of the first element plate


26


, and the portion of hook holes


29


of the second element plate


34


is also cut off. As a result, the end of each band of the first element plate


26


is connected to the end of the adjacent band, and is formed in a spiral form. Therefore, a continuous FAE


11


is formed (see FIG.


2


B). Also both ends of each band


33


of the second element plate


34


are connected to the ends of the bands


33


at both adjacent sides, and formed in a meandering form. Therefore, a continuous SAE


12


is formed (see FIG.


3


B).




The resin support parts


35


of the mounting bracket


13


of the core with mounting bracket


39


and the outer circumference of the core


36


being thus separated are held by the molding die. In this state, by the same insulating resin as in the primary insert molding process, the core with mounting bracket


39


is processed by secondary insert molding so that a threaded portion


13


A of the mounting bracket


13


may be exposed. By this secondary insert molding, as shown in a perspective view in

FIG. 27

, the antenna device of the embodiment is completed by forming a cover


15


for covering the FAE


11


and SAE


12


.




Thus, according to the embodiment, the antenna device small in fluctuation of gain and having two or more impedance characteristics can be manufactured stably by a method hardly causing deformation of antenna elements during the process.




The explanation of the manufacturing method in embodiment 2 relates to the first antenna device of embodiment 1 shown in

FIG. 1

to FIG.


5


. But, the manufacturing method of embodiment 2 may be similarly applied in manufacture of the second to fifth antenna devices shown in

FIG. 6

to FIG.


21


.




INDUSTRIAL APPLICABILITY




As described herein, according to the invention, the antenna device having two or more impedance characteristics, hardly causing uneven pitch or deformation of antenna elements, and high in gain and reliability is easily obtained. The invention also provides a manufacturing method of antenna device having two or more impedance characteristics, hardly causing uneven pitch or deformation of antenna elements, and excellent in productivity.




The antenna device of the invention can be used in wireless unit for mobile communication or the like, personal computer, transceiver, professional communication (for example, taxi, fishing boat, police), and other wireless unit for wireless communication.



Claims
  • 1. An antenna device comprising:a) a first antenna element of spiral form having nearly parallel plural bands formed so that both ends of the plural bands may be connected alternately and consecutively, and formed so that at least one of the plural bands may be projected, b) a second antenna element of meandering form having nearly parallel plural bands formed so that both ends of the plural bands may be connected alternately and consecutively, and formed so that at least one of the plural bands may e projected, c) a core made of an insulating resin for disposing said first antenna element and second antenna element as being insulated from each other, d) a mounting bracket connected to one end of said first antenna element, and e) a cover made of an insulating resin for covering the outer circumference of said first antenna element, second antenna element, core and mounting bracket, while exposing a part of said mounting bracket.
  • 2. The antenna device of claim 1, wherein said plural bands of the first antenna element have a shape so that a conductive thin metal plate is punched and then projected.
  • 3. The antenna device of claim 1, wherein at least two or more bands of said plural bands of the first antenna element are formed to project alternately.
  • 4. The antenna device of claim 3, wherein at least two or more bands of said plural bands of the first antenna element are formed to project alternately in a nearly semicircular form in the longitudinal direction.
  • 5. The antenna device of claim 3, wherein at least two or more bands of said plural bands of the first antenna element are formed to project by every other one in a nearly semicircular form.
  • 6. The antenna device of claim 3, wherein at least two or more bands of said plural bands of the first antenna element are formed to project alternately in a nearly trapezoidal form in the longitudinal direction.
  • 7. The antenna device of claim 3, wherein at least two or more bands of said plural bands of the first antenna element are formed to project by every other one in a nearly trapezoidal form.
  • 8. The antenna device of claim 3, wherein at least two or more bands of said plural bands of the first antenna element are formed to project alternately in a nearly square form in the longitudinal direction.
  • 9. The antenna device of claim 3, wherein at least two or more bands of said plural bands of the first antenna element are formed to project by every other one in a nearly square form.
  • 10. The antenna device of claim 3, wherein at least two or more bands of said plural bands of the first antenna element are formed to project alternately in a nearly polygonal form in the longitudinal direction.
  • 11. The antenna device of claim 3, wherein at least two or more bands of said plural bands of the first antenna element are formed to project by every other one in a nearly polygonal form.
  • 12. The antenna device of claim 1, wherein said plural bands of the second antenna element are formed to project after punching a conductive thin metal plate.
  • 13. The antenna device of claim 1, wherein at least two or more bands of said plural bands of the second antenna element are formed to project in a same direction.
  • 14. The antenna device of claim 13, wherein at least two or more bands of said plural bands of the second antenna element are formed to project in a nearly semicircular form in a same direction.
  • 15. The antenna device of claim 13, wherein at least two or more bands of said plural bands of the second antenna element are formed to project in a nearly trapezoidal form in a same direction.
  • 16. The antenna device of claim 13, wherein at least two or more bands of said plural bands of the second antenna element are formed to project in a nearly square form in a same direction.
  • 17. The antenna device of claim 13, wherein at least two or more bands of said plural bands of the second antenna element are formed to project in a nearly polygonal form in a same direction.
  • 18. The antenna device of claim 1, further comprising an extension for adjustment preliminarily formed for cutting off part of the plural bands of the first antenna element or plural bands of the second antenna element, for adjusting the electric length of the first antenna element or second antenna element.
  • 19. The antenna device of claim 1, wherein the width between junctions at both ends of the plural bands formed spirally in said first antenna element is set smaller than the width between junctions at both ends of the plural bands projecting in a meandering form of said second antenna element.
  • 20. The antenna device of claim 1, wherein the plural bands disposed nearly parallel of said second antenna element are inclined by a specified angle to the plural bands disposed nearly parallel of said first antenna element.
  • 21. The antenna device of claim 1, wherein the insulating resin for forming said core and the insulating resin for forming said cover are the same.
  • 22. The antenna device of claim 1, wherein said mounting bracket is formed integrally with said first antenna element.
  • 23. A manufacturing method of antenna device comprising the steps of:a) forming a first element plate by punching a conductive thin metal plate of a specified dimension and pressing a part of said punched thin metal plate, b) forming a second element plate by a step of punching a conductive thin metal plate of a nearly same dimension as said first element plate, and a step of pressing a part of said punched thin metal plate, c) stacking up the outer circumferential parts of said first element plate and second element plate in the thickness direction, d) insert molding for forming a core having a plurality of resin support parts by fixing the pressed portion of the stacked first element plate and the pressed portion of the second element plate, e) cutting off the outer circumference of said first element plate and second element plate being stacked up, near said core, and separating said core including the pressed portion of said first element plate and the pressed portion of said second element plate from said outer circumference, and f) insert molding for forming a cover for covering the outer circumference by holding said resin support parts of said core.
  • 24. The manufacturing method of antenna device of claim 23,wherein said step of forming said first element plate comprises the steps of: punching a conductive thin metal plate of a specified dimension, and providing nearly parallel plural rectangular holes of same length so that both ends may be convex and concave alternately, thereby forming plural linear portions, separating one side of convex and concave portion of the plural rectangular holes from the outer circumferential part in a linked state, and projecting at least a part of the plural linear portion, in a state coupled to the outer circumference at other side.
  • 25. The manufacturing method of antenna device of claim 23,wherein said step of forming said second element plate comprises the steps of: punching a conductive thin metal plate in a state of plural linear portions linked alternately right and left at narrow linkage, so that nearly parallel plural hook holes of same length may be alternately reverse in direction, separating one side of said plural hook holes from the outer frame in a linked state, and projecting at least a part of said plural linear portions.
Priority Claims (1)
Number Date Country Kind
11-208627 Jul 1999 JP
Parent Case Info

This Application is a U.S. National Phase Application of PCT International Application PCT/JP00/04867.

PCT Information
Filing Document Filing Date Country Kind
PCT/JP00/04867 WO 00
Publishing Document Publishing Date Country Kind
WO01/08256 2/1/2001 WO A
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Number Name Date Kind
4730195 Phillips et al. Mar 1988 A
5910790 Ohmuro et al. Jun 1999 A
6075488 Hope Jun 2000 A
6112102 Zhinong Aug 2000 A
6127979 Zhou et al. Oct 2000 A
6137452 Sullivan Oct 2000 A
6163300 Ishikawa et al. Dec 2000 A
6198442 Rutkowski et al. Mar 2001 B1
6204826 Rutkowski et al. Mar 2001 B1
6232930 Faulkner May 2001 B1
6278415 Matsuyoshi et al. Aug 2001 B1
Foreign Referenced Citations (4)
Number Date Country
3-253009 Nov 1991 JP
7-7112 Jan 1995 JP
409083238 Mar 1997 JP
11-41025 Feb 1999 JP