JPH098689A - Whip antenna and radio - Google Patents

Abstract

(57) [Abstract] [Purpose] A single matching circuit is used to perform impedance matching in the lead-out mode and storage mode of the whip antenna. [Structure] A whip antenna (11a, 11b; 11c, 11d; 11) for a wireless device that is pulled out from the housing 12 when in use and is housed in the housing when not in use or in standby
e. The total length of 11f) is made different between when it is pulled out and when it is stored, so that it is longer than the time when it is pulled out. If the entire length of the whip antenna is longer than that when it is pulled out when it is stored, the antenna input impedance when it is stored and when it is pulled out can be ensured even if conditions such as the antenna length, housing length, and gap length between the antenna and housing change. There can be feed points that are equal. As a result, the matching circuit 15 is connected to the feeding point.
By connecting with, it is possible to achieve impedance matching at the time of storage and at the time of extraction with one matching circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a whip antenna having a structure in which an antenna is pulled out from a housing when in use, and the antenna is housed in the housing when not in use or in a standby state, and a radio equipped with the whip antenna.

[0002]

2. Description of the Related Art A whip antenna has been conventionally used as an antenna used in a portable radio such as a mobile phone. This whip antenna is pulled out from the housing when it is used, and is housed in the housing when not in use or in standby. That is, the whip antenna is used in two modes: a state where it is pulled out from the housing during use and a state where it is stored inside the housing during standby. Therefore, the whip antenna must function in both the retracted and stowed modes. By the way, when an antenna is used in a wireless device, a matching circuit is provided between the wireless circuit and the antenna in order to efficiently radiate radio waves, and impedance matching between the two is performed. The same applies to a radio device equipped with a whip antenna, and a matching circuit is provided so that impedance matching can be achieved in both modes when the whip antenna is pulled out and when it is stored. 15A and 15B are cross-sectional views of a conventional wireless device provided with a whip antenna. FIG. 15A shows a state in which the antenna is pulled out, and FIG. 15B shows a state in which the antenna is housed in a wireless device housing.

In the figure, 1 is a rod-shaped whip antenna,
Reference numeral 2 is a radio housing formed of an insulator, and has a board housing 2a for housing a circuit board and an antenna housing 2b for housing a whip antenna. Reference numeral 3 denotes a substrate on which a wireless circuit and a matching circuit are mounted, and 4 a metal body for electromagnetic shielding, which is installed so as to surround the wireless circuit. A matching circuit 5 is mounted on the circuit board, and is for matching the impedance of the antenna with the characteristic impedance of the wireless circuit. 6 is inserted through the whip antenna 1,
An antenna support fitting for supporting the whip antenna so as to be movable in the vertical direction, 7 is a matching circuit 5 and an antenna support fitting 6
It is a power supply contact metal fitting that electrically connects the two and supplies power to the antenna 1. The whip antenna 1 is formed of, for example, a titanium alloy, and has a knob 1a at the upper end and a stopper 1b at the lower end.
Is provided so that the antenna can be pulled out from the antenna housing portion 2b of the housing (see FIG. 15A) or housed in the antenna housing portion (see FIG. 15B).

The input impedance of the whip antenna 1 used in such a radio varies greatly depending on the position of the feeding point. Therefore, it is not easy to obtain impedance matching in both modes with one matching circuit 5,
Moreover, depending on the conditions such as the antenna length, the length of the housing, and the distance between the antenna and the housing, it is often impossible to perform impedance matching in both modes with one matching circuit.

However, conventionally, (1) how the input impedance of the whip antenna changes depending on whether the whip antenna is pulled out or housed, and (2) the total length of the whip antenna We have not examined how the elements such as the antenna and its placement affect the input impedance of the whip antenna, and we have adjusted the impedance matching by trial and error. In particular, conventionally, the state where the input impedances are the same when the whip antenna is pulled out and when the whip antenna is stored is not actively searched for. For example, we have not taken the method of positively adjusting the feed position of the whip antenna to match the impedances when it is pulled out and when it is stored. I was just saying that it was the end where power could be supplied.

As described above, conventionally, by trial and error adjustment, one matching circuit is used to perform impedance matching in both the mode when the whip antenna is pulled out and when the whip antenna is retracted, and the adjustment work is not easy. Moreover, no matter how the adjustment was made, impedance matching could not be obtained in both modes. Therefore, in order to eliminate the difficulty of matching by matching the input impedances in both modes (drawing mode and storage mode), a matching circuit is provided corresponding to each mode, and the matching circuit is set according to the mode. Are being switched. In this method, a mechanism such as a switch is provided to operate different matching circuits when the whip antenna is pulled out and when the whip antenna is housed, and impedance matching is performed in each mode, so that impedance matching can be reliably performed.

[0007]

However, in such a method, two systems of matching circuits must be provided, and a mechanism such as a switch for switching the matching circuits is also required,
There is a problem that the structure becomes complicated as a whole and the cost becomes high. From the above, the object of the present invention is to provide a matching circuit that
It is an object of the present invention to provide a whip antenna and a wireless device that can perform impedance matching in a pull-out mode and a storage mode of a whip antenna with one matching circuit without providing a system. Another object of the present invention is to ensure that the input impedances in both modes are matched and impedance matching is performed with one matching circuit regardless of the antenna length, the housing length, and the distance between the antenna and the housing. Another object of the present invention is to provide a whip antenna and a radio that can be used. Still another object of the present invention is to provide a whip antenna and a radio which can increase the degree of freedom in antenna design for impedance matching with one matching circuit in both modes.

[0008]

FIG. 1 is a diagram illustrating the principle of the present invention. In FIG. 1 (A), 11a is a rod-shaped first antenna element that can be pulled out and stored, and 11b is a rod-shaped second antenna element with a predetermined length, and when the first antenna element is stored, It makes electrical contact with the lower end to increase the antenna length,
A receiving portion 11b-1 which is separated from the first antenna element when the first antenna element is pulled out, and 11b-1 is provided at an upper end portion of the second antenna element and receives a stopper provided at a lower end of the first antenna element. Is. 1
Reference numeral 2 denotes a wireless device housing, which has a circuit board housing portion 12a and an antenna housing portion 12b. Reference numeral 13 is a circuit board on which a wireless circuit or the like is mounted, 15 is a matching circuit for matching impedance between the wireless circuit and the antenna in both extraction and storage modes of the whip antenna, and 16 is a movable first antenna element 11a. A holding member that holds the first antenna element and makes electrical contact with the first antenna element; 17 is a power feeding unit that connects the antenna and the output terminal of the matching circuit via the holding member; and 18 is the first antenna element when the first antenna element is stored. The second antenna element fixing portion fixes the second antenna element 11b so as to make electrical contact with the lower end portion of the first antenna element.

In FIG. 1B, 11c is a conductor portion 11c-
The rod-shaped first antenna element is provided with an insulator 11c-2 at the tip of 1 and can be pulled out from and housed in the radio housing 12, and a knob 11 is provided at the upper end of the first antenna element.
c-3 and a stopper 11c-4 at the lower end. Reference numeral 11d is a second antenna element fixed to the upper part of the antenna housing portion 12b in the radio housing 12 so that the first antenna element is movably inserted therein and electrically contacting the conductor portion of the first antenna element. It also has a function as a support fitting for the first antenna element. In FIG. 1C, 11e is a rod-shaped first antenna element that can be pulled out from and housed in the radio housing 12.
Reference numeral 11f is a second antenna element, and 11g is a holder provided on the upper end of the first antenna element and formed of an insulator that movably holds the second antenna element.

[0010]

[Operation] The total length of the whip antenna for the wireless device, which is pulled out from the housing during use and stored in the housing when not in use or in standby, is made different between when it is pulled out and when it is stored. Make it longer than the total length. If the total length of the whip antenna when stored is longer than the total length when it is pulled out,
Even if conditions such as the antenna length, the length of the housing, and the distance between the antenna and the housing change, it is possible to ensure that there is a feeding point at which the antenna input impedances at the time of storage and at the time of extraction are equal. As a result, by connecting a matching circuit to the feeding point, one matching circuit can perform impedance matching at the time of storage and at the time of drawing. ... Claim 1 and Claim 8

In order to make the total length of the whip antenna longer than when the whip antenna is pulled out, the whip antenna is shown in FIG.
As shown in (A), a first antenna element 11a having a predetermined length L1 that can be pulled out from and housed in the radio housing 12, and an antenna housing portion 12b in the radio housing.
Is fixed below the first antenna element 11a and electrically contacts the lower end portion of the first antenna element 11a when the first antenna element 11a is housed to increase the antenna length, and when the first antenna element 11a is pulled out, the first antenna element 11a is pulled out. A rod-shaped second antenna element 12 having a predetermined length L2 which is separated from the element
a. According to the configuration of FIG. 1 (A), the total length of the antenna when it is pulled out is L1, and when it is stored (L1 + L2)
And can be made longer when stored than when pulled out. A bulge portion formed at the lower end of the first antenna element 11a at the tip of the second antenna element 11b.
By providing the receiving portion 11b-1 for receiving the (stopper), the first and second antennas can be surely brought into electrical contact when the antenna is housed. ... Claims 2, 3,
9, 10

Further, in order to make the whole length of the whip antenna longer when the whip antenna is stored, the whip antenna is shown in FIG.
As shown in (B), a rod-shaped first antenna that is provided with an insulator 11c-2 having a length L2 'at the tip of a conductor portion 11c-1 having a length L1 and that can be pulled out and stored from the radio housing 12 The first antenna element 1 is fixed to the element 11c and the antenna housing 12b in the radio housing.
1c is movably inserted and has a predetermined length L that makes electrical contact with the conductor portion 11c-1 of the first antenna element.
2 (> L2 ') 2nd antenna element 11d is provided. According to the configuration of FIG. 1B, the total length of the antenna when it is pulled out is L1, and it is approximately (L1 + L2) when it is stored, so that the total length of the antenna can be made longer when it is stored.

The first antenna element 11c has a stopper 11c-4 at the lower end and a knob 11c-3 at the upper end so that the first antenna element 11c-4 engages with the lower end of the second antenna element. The element 11c is pulled out, and the first antenna element 11c is pushed in and housed until the knob 11c-3 engages with the upper end portion of the second antenna element 11d. By doing so, it is possible to reliably connect the first and second antenna elements at the time of storage and to make the total length of the antenna longer than when the antenna is pulled out. Furthermore,
The length L2 of the second antenna element 11d is equal to the insulator length L
By making the length a little longer than 2 ', the insulator 11c-2 is housed in the second antenna element 11d when the first antenna element 11c is housed, and the second antenna element 11d is placed in the conductor portion 11c of the first antenna element 11c. -1 can be electrically contacted. ... Claims 4, 5, 6, 11

Further, in order to make the total length of the whip antenna longer when it is retracted than when it is retracted, the whip antenna is rod-shaped with a length L1 that can be retracted and accommodated from the radio housing 12 as shown in FIG. 1C. Of the first antenna element 11e, the second antenna element 11f having a length L2, and an insulator provided at the upper end of the first antenna element 11e and movably holding the second antenna element 11f. The holder 11g is provided. According to the configuration of FIG. 1C, the second antenna element 1 is pushed by the pushing force when the antenna is stored.
The lower end of 1f is brought into electrical contact with the upper end of the first antenna element 11e to set the antenna length to (L1 + L2), and when the antenna is pulled out, the second antenna element 11f is pulled from the first antenna element 11e by a pulling force. The antenna length is set to L1 by separating them. As a result, the total length when the antenna is stored can be made longer than when the antenna is pulled out. ... Claims 7 and 12

If there is a feeding point where the antenna input impedance is the same even when the antenna is pulled out and the antenna is housed without changing the total length of the antenna, a matching circuit is connected to the feeding point to make one matching. Make impedance matching in the circuit. ... Claim 13

[0016]

【Example】

(A) Consideration by computer simulation (b) Consideration on general wireless device configuration In order to more concretely explain the conventional problems and the principle of the present invention, the input impedance characteristic of the whip antenna in the portable wireless device is considered. To do. FIG. 2 is a cross-sectional view showing the structure of a general wireless device such as a mobile phone.
It has the same structure as that shown in FIG. The whip antenna 1 has a structure in which it is pulled out from the insulator housing 2 or is housed in the housing. There is a board 3 on which a wireless circuit is mounted in the housing, and a metal body 4 for electromagnetic shielding is installed so as to surround the wireless circuit. Further, a matching circuit 5 for matching the impedance of the whip antenna with the characteristic impedance of the wireless circuit is provided on the substrate, and power is supplied to the whip antenna 1 from there through a power supply contact fitting 7.

As shown in FIG. 3, the whip antenna 1 having the structure in which the circuit board 3 and the metal body 4 such as its shield and the like which are present in the vicinity of the circuit board 3 and are pulled out or housed is used as shown in FIG. We modeled it on a grid and analyzed its impedance characteristics. For the calculation, the electromagnetic analysis simulator "Numerical Electromagnetics Code"
(NEC-2) ”(manufactured by Lawrence Livermore Laboratory) was used.
Fig. 4 shows the locus of the impedance change of the antenna on the Smith chart. Whip antenna 1 with a total length of L = 100 mm, which is a straight conductor, is gradually pulled out from radio case 2, whip at a frequency of 1.5 GHz. The change in the input impedance of the antenna is shown using the extraction length (extraction length from the feeding point) lp as a parameter. still,
The total length of the antenna is 100 mm, the size of the metal housing is 46 x 20 x 130 m
m, the distance d between the housings is 10 mm, and the total length of the antenna is 100
mm is a half wavelength of 1.5 GHz.

From the time when the whip antenna 1 is completely housed (1p = 0), the whip antenna is gradually pulled out (increases 1p) until the whip antenna 1 is completely pulled out (1p = 100mm). , Frequency 1.5GH
The input impedance at z draws a loop-shaped locus as shown on the Smith chart. In this way, the loci of impedance intersect again or become close to each other where the impedance is high when the whip antenna is housed and when it is pulled out.

In FIG. 4, the loci of impedance intersect. That is, there is a point where the impedance is the same when the whip antenna is pulled out and when it is stored. Therefore, if this point is set as the feeding position when the whip antenna is pulled out and when the whip antenna is housed, the impedances of both modes can be perfectly matched by one matching circuit. FIG.
FIG. 4A is an explanatory diagram of a power feeding position in such a case, where (a) shows a power feeding position in an antenna withdrawn state, and (b) shows a power feeding position in an antenna housed state. When the antenna is pulled out, the position where the antenna is pulled out by 95 mm is the feeding position, and when the antenna is stored, the antenna is 23 mm from the feeding position.
The protruding position is the power feeding position. With this configuration, the impedances match when the antenna is pulled out and when the antenna is stored.

By the way, in the example of FIG. 4, there is an impedance matching intersection, but for example, the total length L of the whip antenna is shortened, the distance d between the whip antenna and the metal portion of the housing is shortened, or the metal housing portion is used. If the total length T of the whip antenna is lengthened, the influence of the metal casing portion on the impedance of the whip antenna becomes stronger, and particularly when the whip antenna is housed. In such a case, the loci of impedance changes do not intersect, and there are no intersections of impedance matching. In addition, it has been clarified by simulation calculation that the loci do not intersect. In this way, if there is no impedance matching intersection, no matter how the feeding position or matching circuit is adjusted,
Impedance matching cannot be achieved in the antenna extraction mode and the antenna accommodation mode by one matching circuit.

In the case of FIG. 4, the point where the impedances match in both the pulling-out and storing modes is 1 as a matter of course.
It is limited to one. That is, when the structure of the wireless device and the total length of the antenna are determined, the position of the feeding point when the antenna is pulled out and stored and the length of the portion where the whip antenna projects from the housing are determined. Originally, considering that the protrusion length of the whip antenna should be optimized from the radiation pattern characteristics, it is understood that the conventional whip antenna has a considerably limited degree of freedom in antenna design. Furthermore, depending on the conditions such as the antenna length and the length of the housing, there is no point where the impedances match in both modes, as described above.

(B) Principle of the Present Invention FIG. 6 shows the impedance locus of FIG.
And the impedance locus at 90 mm (mainly when the antenna is pulled out) are superimposed, and the part where the loci of impedance intersect is enlarged. As you can see from Figure 6,
The impedance locus when the antenna with a total length of 100 mm is housed (when lp is small) is not only the impedance locus when the antenna with a total length of 100 mm is pulled out, but also with the impedance locus when the antenna with a total length of 95 mm or 90 mm is pulled out (when lp is large). There are matching points. In addition, the impedance loci intersect deeply as the difference between the total lengths of the drawn state and the stored state increases. Applying this result, if the total length of the antenna is variable when the antenna is pulled out and when the antenna is stowed, it is possible to freely adjust the antenna feed length and the antenna protrusion length from the housing when the impedances match in both modes. It can be set, and the degree of freedom in antenna design can be given.

More specifically, for example, if the total length L of the antenna is 100 mm both when it is pulled out and when it is stored, the antenna protrusion length 1p when it is pulled out is about 95 mm, and when the antenna protrusion length 1 p is about 1 mm when it is stored. The impedance matches at 23 mm. Therefore, if this point is used as a feeding point, the antenna functions well in both modes with one matching circuit. However, when the total length of the antenna is not changed when the antenna is pulled out and when the antenna is stored, the feeding point of the antenna, that is, the protruding length of the antenna is determined to be one from the viewpoint of impedance, and the degree of freedom in antenna design is small. However, as described above, there is a demand to optimize the protrusion length of the whip antenna from the radiation pattern characteristics. If there is such a demand, for example, by providing a structure in which the total length when the whip antenna is pulled out is 95 mm and the total length when the whip antenna is retracted is 100 mm, the intersection point of impedance matching as shown in FIG. You can change the protrusion length 1p = 80mm and the protrusion length 1p = 27mm when stored. In FIG. 7, reference numeral 8 denotes an antenna addition element that is coupled to the antenna body when it is stored. In addition, by providing a structure that allows the total length when the whip antenna is pulled out to be 90 mm and the total length when it is stored to be 100 mm, the intersection point of impedance matching is projected at a protrusion length of 1 p when the whip antenna is pulled out as shown in FIG.
It can be changed to 72 mm and the protruding length when stored is 1 p = 32 mm.

As described above, by appropriately selecting the total length when the antenna is pulled out and when the antenna is stored, it is possible to adjust the antenna protrusion length (feeding point position) without deteriorating the impedance characteristics, and as a result, radiation is performed. It is possible to optimize characteristics such as patterns. Further, as described above, in the case where the total length of the antenna is the same when the antenna is pulled out and when it is stored, the total length L of the antenna is shortened or the distance d between the antenna and the metal housing is shortened.
If the total length T of the metal casing is increased, the influence of the metal casing on the antenna impedance becomes stronger, and the intersection point of impedance matching does not exist. For example, in FIG. 3, when the total length L of the antenna is changed from 100 mm to 90 mm, the impedance matching intersection point does not exist. Similarly, FIG.
The distance d between the antenna and the metal housing is 10mm to 5m
At m, the impedances will not match. FIG. 9 is an explanatory diagram of the locus of impedance when the distance d between the antenna and the housing is changed. As is clear from this figure, when the distance d between the antenna and the metal casing is set to 5 mm, the locus intersection point does not exist, and the larger d is, the deeper the loci of impedance intersect.

The first method effective when the impedance loci do not intersect is the total length L of the antenna when stored.
Is to lengthen. If the total length L of the antenna is set to be longer than half the wavelength, the distance d between the antenna and the metal housing will be 5 mm or 2
It has been clarified by simulation that the existence of the intersection of the impedance loci can be guaranteed even when shortened to mm. There is a limit to the length of the antenna,
Note that if it is too long, it will not fit in the housing. A second effective method in the case where the impedance loci do not intersect is to make the total length of the antenna at the time of storage longer than the total length at the time of extraction. Considering FIG. 6, as described above, the intersection point of the impedance loci can be guaranteed by making the total antenna length during storage longer than the total antenna length during extraction. In addition, as the total length when stored is made longer than the total length when pulled out, and the difference is increased, the loci of impedance can be deeply intersected. Therefore, even if the influence of the metal housing on the antenna impedance becomes large due to the distance d between the antenna and the housing becoming shorter, the total length of the antenna when pulled out should be set shorter than the total length when stored. Thus, it is possible to guarantee the existence of the intersection point of impedance matching. By using this second method, it is possible to find the intersection point of impedance matching without setting the total length of the antenna to a half wavelength or longer.

As described above, under various conditions when designing a radio device and its antenna, in order to match the impedance when the antenna is pulled out and when the antenna is stored,
It is an effective method to set the total length of the antenna to a half wavelength or more, or to set the total length when pulled out to be shorter than the total length when stored. In particular, the total length of the antenna when it is pulled out and the total length when it is stowed are variable, and by appropriately selecting the respective lengths, there is an effect that the antenna protrusion length can be optimally designed while matching the impedance in both states. .

(B) First Embodiment of the Present Invention FIG. 10 is a cross-sectional view of a wireless device equipped with a whip antenna according to the first embodiment of the present invention, (a) is a cross-sectional view when the antenna is pulled out, ( b) is a sectional view when the antenna is stored. 11
a is a rod-shaped first antenna element having a predetermined length L1 that can be pulled out and stored, 11b is a rod-shaped second antenna element having a predetermined length L2, and the lower end portion of the first antenna element when the first antenna element is stored The first antenna element is separated from the first antenna element when the first antenna element is pulled out. The first and second antenna elements 11a,
A whip antenna is formed by 11b.

A knob 11a-2 is formed at the upper end of the conductor portion 11a-1 of the first antenna element, and a stopper 11a-3 having a diameter larger than that of the conductor portion is formed at the lower end. The antenna is pulled out or stored by holding the knob portion 11a-2. The stopper 11a-3 engages with the lower end of an antenna support fitting described later when the antenna is pulled out, and
It has a function of preventing a from being pulled out from the housing, and a function of letting the operator recognize that the antenna has been fully pulled out. At the upper end of the second antenna element,
A receiving portion 11b-1 for receiving the stopper 11a-3 of the first antenna element is provided, and the stopper 11a-3 is provided when the antenna is housed.
Are fitted in the receiving portion 11b-1 so that mutual electrical contact can be surely obtained.

Reference numeral 12 denotes a radio housing, which has a circuit board housing portion 12a and an antenna housing portion 12b. Reference numeral 13 is a circuit board on which a wireless circuit or the like is mounted, 14 is a metal body for electromagnetic shielding that is installed so as to surround the wireless circuit, and 15 is impedance matching between the wireless circuit and the antenna in both antenna extraction and storage modes. A holding circuit for holding the first antenna element 11a so that the first antenna element 11a is movable, and a holding metal for electrically contacting the first antenna element. 17 is between the antenna and the output terminal of the matching circuit via the holding metal. A reference numeral 18 designates a contact metal fitting for power supply, which is a second antenna element fixing portion for fixing the second antenna element 11b to the housing.

FIG. 11 is an explanatory view of the main part of the wireless device of the first embodiment, and the same parts as those in FIG. 10 are designated by the same reference numerals. On the circuit board 13, a transmitter circuit 13c-1, a receiver circuit 13c-2, a matching circuit 15, and a duplexer 13c-3 for connecting the transmitter circuit 13c-1 and the receiver circuit 13c-2 to the matching circuit 15 are provided. . The matching circuit 15 has a filter configuration including a coil 15a and a chip capacitor 15b, one end of which is connected to the duplexer 13c-3, and the other end of which is electrically connected to the antenna via a power supply contact fitting 17 and an antenna support fitting 16. Connected to each other to feed the antenna.
Incidentally, 16a is a feeding point to the antenna. Transmission circuit 13c-
The RF signal from 1 is input to the matching circuit 15, and is fed / transmitted from the matching circuit 15 to the antenna support fitting 16 and the antenna through the feeding contact fitting 17. The RF signal received by the antenna 11 follows the reverse route and is input to the receiving circuit 13c-2.

When talking on the radio, the antenna is pulled out and power is supplied to the lower end of the antenna as shown in FIG. 10 (a). When in standby mode, the antenna is shown in Fig. 10 (b).
The antenna is stored as shown in (the antenna knob 11a-2 is out of the radio housing), and power is supplied near the top of the antenna. The protruding length Lp of the antenna at this time is designed not only for the purpose of picking up and pulling out the antenna, but also for considering the radiation characteristic of the radio wave during storage. Second antenna element 11
b is the lower end stopper 11a-3 and the receiving portion 11b-1 of the first antenna element 11a when the first antenna element 11a is stored (FIG. 10 (b)).
It is fixed at a position where and are engaged. Thus, the second
Since the antenna element 11b is fixed to the radio housing 12b, it completely separates when the first antenna element 11a is pulled out, and does not function as an antenna when pulled out.

That is, the total length when the antenna is pulled out is
The length L1 is the same as the length of the first antenna element 11a, and the total length when stored is the sum of the lengths L1 and L2 of the first and second antenna elements 11a and 11b. As described above, if the total length of the antenna is longer than when it is pulled out when it is stored, it can be reliably stored and withdrawn even if conditions such as the antenna length, housing length, and gap length between the antenna and housing change. There can be feed points with equal input impedance. As a result, by connecting the matching circuit 15 to the feeding point and feeding the power, it is possible to perform impedance matching between the housed state and the drawn state with one matching circuit 15. Also, with the above structure, it becomes easy to match the input impedance when the antenna is pulled out and when the antenna is housed, and the antenna protrusion length, which is a parameter that affects the radiation characteristics in both states, is freely designed. Will be able to.

(C) Second Embodiment of the Present Invention FIG. 12 is a cross-sectional view of a wireless device equipped with a whip antenna according to the second embodiment of the present invention. (A) is a cross-sectional view when the antenna is pulled out, (b) ) Is a cross-sectional view when the antenna is stored. 12, the same parts as those of the first embodiment of FIG. 10 are designated by the same reference numerals. Reference numeral 11c is a rod-shaped first antenna element that can be pulled out from and housed in the radio housing 12.
A conductor portion 11c-1 having a length L1 is provided with an insulator portion 11c-2 having a length L2 'at a tip thereof, and a knob 11c-3 is formed at the tip thereof, and a lower end of the conductor portion has a diameter smaller than that of the conductor portion. Big stopper
11c-4 is formed. Pull out or store the antenna with the knob 11c-3. The stopper 11c-4 engages with the lower end of a second antenna element (described later) when the antenna is pulled out to prevent the first antenna element 11a from being pulled out from the housing, and also allows the operator to fully pull out the antenna. It has a function to recognize the fact.

Reference numeral 11d is a cylindrical second antenna element having a length L2 (> L2 '), and the antenna housing portion 12 is provided.
It is fixed to the upper part of b and has a function as an antenna and also has a function of movably supporting the first antenna element 11c. Second antenna element 1
The first antenna element 11a is vertically movably inserted into the cylindrical portion 1d, and the inner surface of the cylindrical portion and the conductor portion 11c-1 of the first antenna element are electrically contacted with each other. ing. The length L2 of the second antenna element 11d is determined by the first antenna element 11c.
It is slightly longer than the length of the insulator part 11c-2. A whip antenna is formed by the first and second antenna elements 11c and 11d.

When the antenna is pulled out (FIG. 12 (a)), the second antenna element 11d functions as an antenna support fitting, and the total length of the antenna at this time is L1 which is the same as the length of the first antenna element 11c. Become. When the antenna is housed (Fig. 12 (b)), the second antenna element 1
Since the length L2 of 1d is made slightly longer than the insulator length L2 ', the insulator portion 11c-2 has the second antenna element 11d.
Of the second antenna element 11d and the conductor portion 11 of the first antenna element 11c.
Electrical contact between c-1 is maintained. As a result, the total length of the antenna when stored is approximately equal to the sum of L1 and L2. With this structure, it is easy to match the input impedance when the antenna is pulled out and when the antenna is housed, and the antenna protrusion length, which is a parameter that affects the radiation characteristics in both states, can be freely designed. Will be able to.

(D) Third Embodiment of the Present Invention FIG. 13 is a cross-sectional view of a wireless device equipped with a whip antenna according to the third embodiment of the present invention, (a) is a cross-sectional view when the antenna is pulled out, and (b) ) Is a cross-sectional view when the antenna is stored. 13, the same parts as those in the first embodiment of FIG. 10 are designated by the same reference numerals. Reference numeral 11e is a rod-shaped first antenna element having a predetermined length L1 that can be pulled out and stored from the radio housing 12, 11f is a second antenna element having a predetermined length L2,
11g is provided on the upper end of the first antenna element,
It is a holder formed of an insulator that movably holds the second antenna element. A whip antenna is configured by the first and second antenna elements 11e and 11f and the holder 11g.

Second antenna element 11 of length L2
f is connected to the first antenna element 11e having a length L1 by an insulator holder 11g, and the first antenna element 11e is held in the radio housing 12 by an antenna support fitting 16. Insulator holder 11
There is a gap between the two antennas within g, and the second antenna element 11f has a structure that can freely slide within the holder. Therefore, when the second antenna element 11f is picked up and pulled when the antenna is pulled out, the pulling force separates the first and second antenna elements 11e and 11f from each other in the holder to cause no contact. Has a total length of L1.

On the other hand, when the second antenna element 11f is held and pushed in at the time of storage, the pushing force causes the first and second antenna elements 11e, 11 in the holder.
The fs are engaged with each other and come into contact with each other. At this time, the total length of the operating antenna is L1 + L2. With such a structure, it becomes easy to match the input impedance when the antenna is pulled out and when the antenna is housed, and the antenna protrusion length, which is a parameter that affects the radiation characteristics in both states, can be freely designed. become able to.

(E) Fourth Embodiment of the Present Invention FIG. 14 is a sectional view of a radio device according to a fourth embodiment of the present invention, (a) is a sectional view when the antenna is pulled out, and (b) is an antenna housed. FIG. 14, the same parts as those in the first embodiment of FIG. 10 are designated by the same reference numerals. First to third
In the embodiment, the total length of the antenna when stored is made longer than the total length of the antenna when pulled out, a feeding point at which the input impedance of the antenna is the same during storage and when pulled out is obtained, and the matching point is connected to the feeding point to feed the antenna. It was something to do.
However, when there is a feeding point that can match the input impedance without changing the total length of the antenna, the degree of freedom in antenna design is reduced, but the total length of the antenna does not necessarily need to be changed.

As described above, the input impedance of the antenna largely changes depending on the position of the feeding point, and the input impedance is the antenna element length L, the distance d to the conductor existing near the antenna, and the size of the radio device. Is also strongly influenced by. Therefore, by computer simulation or actual impedance measurement, we found a point where the impedance was the same when the antenna was pulled out and when it was stored without changing the total length of the antenna, and the position of that point was set as the feeding point when the antenna was pulled out and when it was stored. To do. This reduces the degree of freedom in antenna design, but has the effect of reducing impedance mismatch loss in both modes and reducing antenna efficiency degradation.

In FIG. 14, stoppers 11a provided at both ends of the antenna element 11 and having a diameter larger than that of the conductor portion 11a-1 are provided.
-3, by changing the length of the knob 11a-2, it is possible to adjust the position of the power feeding point during withdrawal and storage. As a result, the feeding point position when the antenna is pulled out is
The antenna can be adjusted to a position of a distance p1 from the lower end of the antenna with respect to the total length L of the antenna and to a position of a distance p2 from the upper end of the antenna when stored, so that the impedances in both modes can be matched. Although the present invention has been described above with reference to the embodiments, the present invention can be variously modified according to the gist of the present invention described in the claims, and the present invention does not exclude these.

[0042]

As described above, according to the present invention, the total length of the whip antenna is made different between when it is pulled out and when it is stored, and the total length when stored is longer than the total length when it is pulled out.
Even if conditions such as the antenna length, the length of the housing, and the distance between the antenna and the housing change, it is possible to ensure that there is a feeding point at which the antenna input impedances at the time of storage and at the time of extraction are equal. As a result, by feeding power to the feeding point, 1
Impedance matching at the time of storing and pulling out can be achieved by one matching circuit. In addition, it becomes easy to match the input impedance when the antenna is pulled out and when the antenna is housed, and it is possible to freely design the antenna protrusion length, which is a parameter that affects the radiation characteristics and the like in both states. .

According to the present invention, the first antenna element that can be pulled out from the radio housing and stored, and the lower end of the first antenna element that is fixed below the antenna storage portion when the first antenna element is stored. A second antenna that electrically contacts the portion to increase the antenna length and separates from the first antenna element when the first antenna element is pulled out.
A whip antenna is constructed with the antenna element of. With this configuration, the total length of the antenna when stored can be made longer than the total length of the antenna when pulled out with a simple structure. Further, by providing a receiving portion for receiving the stopper portion formed at the lower end portion of the first antenna element at the tip of the second antenna element, the first and second antennas can be surely electrically contacted when the antenna is housed. Can be made.

Further, according to the present invention, the first antenna element having the insulator of length L2 'at the tip of the conductor portion of length L1 is fixed to the upper part of the antenna housing portion in the radio housing. , A second antenna element having a predetermined length L2 (> L2 ') that movably supports the first antenna element and is in electrical contact with the conductor portion of the first antenna element, and forms a whip antenna. . With this configuration, the total length of the antenna when stored can be made longer than the total length of the antenna when pulled out with a simple structure.

Further, a stopper is provided at the lower end of the first antenna element and a knob is provided at the upper end, and the first antenna element is pulled out until the stopper engages with the lower end of the second antenna element. The first antenna element is pushed and stored until it engages with the upper end. By doing so, it is possible to reliably connect the first and second antenna elements at the time of storage and to make the total length of the antenna longer than when the antenna is pulled out. Further, the length L2 of the second antenna element is set to the insulator length L
By making it slightly longer than 2 ', the second antenna element can be reliably brought into electrical contact with the conductor portion of the first antenna element when the first antenna element is housed.

Further, the first antenna element that can be pulled out from and housed in the radio housing, the second antenna element having a predetermined length, and the second antenna element provided at the upper end of the first antenna element A whip antenna is configured with a holder formed of an insulator that holds it movably, and when the antenna is housed, the second antenna element is brought into contact with the first antenna element by the pushing force, and when the antenna is pulled out, the first antenna element is pulled by the pulling force. The second antenna element is separated from the first antenna element. With this configuration, the total length when the antenna is housed can be made longer than the total length when the antenna is pulled out with a simple structure. Further, according to the present invention, even if the total length of the antenna is not changed between when the antenna is pulled out and when the antenna is housed, if there is a feeding point where the input impedance is the same in both modes, the feeding point is calculated, Power the antenna from the feeding point. By doing so, impedance matching can be achieved by one matching circuit, impedance mismatch loss in both modes can be reduced, and antenna efficiency deterioration can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a cross-sectional view showing structures of a wireless device and an antenna.

FIG. 3 is an explanatory diagram of a wire grid model.

FIG. 4 is a locus diagram of a change in impedance of an antenna.

FIG. 5 is an explanatory diagram of a power feeding position.

FIG. 6 is a locus diagram of impedance when the total antenna length L is variable.

FIG. 7 is an explanatory diagram of a power feeding position when the total length of the antenna is changed between when it is pulled out and when it is stored.

FIG. 8 is an explanatory diagram of another power feeding position when the total length of the antenna is changed between when it is pulled out and when it is stored.

FIG. 9 is an impedance locus diagram when the distance between the antenna and the housing is changed.

FIG. 10 is a configuration diagram of a wireless device including a whip antenna according to the first embodiment.

FIG. 11 is an explanatory diagram of a main part of a wireless device.

FIG. 12 is a configuration diagram of a wireless device including a whip antenna according to a second embodiment.

FIG. 13 is a configuration diagram of a wireless device including a whip antenna according to a third embodiment.

FIG. 14 is a configuration diagram of a wireless device according to a fourth embodiment.

FIG. 15 is a sectional view of a conventional portable wireless device.

[Explanation of symbols]

 11a, 11c, 11e ··· First antenna element 11b, 11d, 11f ··· Second antenna element 12 · · Radio housing 13 · · Circuit board 15 · · Matching circuit 16 · · Holding bracket 17 · · Power supply contact Metal fitting 18 ··· Second antenna element fixing part

Claims (13)

[Claims] 1. When using, the antenna is pulled out from the housing,
A whip antenna for a wireless device, which has a structure in which the antenna is stored in the housing when not in use or in standby, characterized in that the entire length of the antenna is switched while the impedance is almost the same when the antenna is pulled out and when it is stored. 2. The whip antenna is fixed to a first antenna element that can be pulled out from and housed in a radio housing, and is fixed below an antenna housing portion in the radio housing.
When the first antenna element is housed, the antenna length is increased by making electrical contact with the lower end portion of the first antenna element to increase the antenna length, and when the first antenna element is pulled out, the antenna is separated from the first antenna element by a predetermined length. The whip antenna according to claim 1, further comprising a second antenna element. 3. The whip antenna according to claim 2, wherein the tip of the second antenna element is provided with a receiving portion for receiving the lower end portion of the first antenna element. 4. The whip antenna is provided with an insulator having a length L2 ′ at a tip of a conductor portion having a length L1.
A first antenna element that can be pulled out from and housed in the radio housing, and is fixed to the upper part of the antenna housing in the radio housing,
The first antenna element includes a second antenna element having a predetermined length L2 (> L2 ′), which is movably inserted into the first antenna element and is in electrical contact with a conductor portion of the first antenna element. The whip antenna according to claim 1, wherein the whip antenna operates as an antenna having a total length of L1 when pulled out, and operates as an antenna having a total length of (L1 + L2) when housing the first antenna element. 5. The first antenna element is provided with a stopper at the lower end and a knob at the upper end so that the first antenna element can be pulled out until the stopper engages with the lower end of the second antenna element. The whip antenna according to claim 4, wherein the first antenna element can be housed until the first antenna element is engaged with the upper end portion of the second antenna element. 6. The second antenna element length L2 is made longer than the insulator length L2 ′, whereby the insulator is housed in the second antenna element in the housed state of the first antenna element, and the second antenna element is The whip antenna according to claim 5, wherein the whip antenna is configured to make electrical contact with the conductor portion of the first antenna element. 7. The whip antenna has a first length L1 that can be pulled out and stored from a radio housing.
Antenna element, a second antenna element having a length L2, and a holder that is provided at the upper end of the first antenna element and is formed of an insulator that movably holds the second antenna element. The lower end of the second antenna element is electrically contacted with the upper end of the first antenna element during storage to set the antenna length to (L1 + L2), and the second antenna element is separated from the first antenna element when the antenna is pulled out. The whip antenna according to claim 1, wherein the antenna length is L1. 8. In a wireless device for transmitting and receiving a signal by wireless, a circuit board on which a wireless circuit is mounted, and a wireless device that is pulled out from the wireless device housing when in use and is housed in the housing when not in use or in standby A whip antenna with a structure that switches the total length of the antenna between when it is stored and when it is stored, a matching circuit that controls impedance matching between the radio circuit and the antenna, and the input impedance of the antenna becomes the same when the antenna is pulled out and when the antenna is stored. A wireless device comprising a power feeding unit for feeding power from a matching circuit to an antenna position. 9. The whip antenna is fixed to a first antenna element in the form of a rod that can be pulled out and stored, and below an antenna storage portion in a radio housing,
When the first antenna element is housed, the antenna length is increased by making electrical contact with the lower end portion of the first antenna element to increase the antenna length, and when the first antenna element is pulled out, the antenna is separated from the first antenna element by a predetermined length. The wireless device according to claim 8, further comprising a second antenna element. 10. The wireless device includes a holding metal member for movably holding the first antenna element and electrically contacting the first antenna element, and a second antenna for fixing the second antenna element to a housing. The radio device according to claim 9, further comprising an element fixing portion. 11. The whip antenna comprises an insulator having a length L2 ′ at a tip of a conductor portion having a length L1.
A first antenna element that can be pulled out from and housed in the radio housing, and is fixed to the upper part of the antenna housing in the radio housing,
The first antenna element is movably held and includes a second antenna element having a predetermined length L2 (> L2 ') that electrically contacts the conductor portion of the first antenna element. 9. The radio device according to claim 8, wherein the radio device sometimes operates as an antenna having a total length L1 and operates as an antenna having a total length of approximately (L1 + L2) when the first antenna element is housed. 12. The whip antenna has a first length L1 that can be pulled out and stored from a radio housing.
Antenna element, a second antenna element having a length L2, and a holder provided at the upper end portion of the first antenna element and formed of an insulator that movably holds the second antenna element. The lower end of the second antenna element is electrically contacted with the upper end of the first antenna element during storage to set the antenna length to (L1 + L2), and the second antenna element is separated from the first antenna element when the antenna is pulled out. 9. The wireless device according to claim 8, wherein the antenna length is set to L1. 13. A wireless device for transmitting and receiving a signal wirelessly, comprising: a circuit board on which a wireless circuit is mounted; and a whip antenna which is pulled out from the wireless device housing when in use and is housed in the housing when not in use or in standby. A matching circuit that controls impedance matching between the wireless circuit and the antenna; and a power feeding unit that feeds power from the matching circuit to an antenna position where the input impedance of the antenna is equal when the antenna is pulled out and when the antenna is housed. transceiver.