JP3180034B2 - antenna - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitting / receiving antenna for a portable device such as a portable telephone, a radio such as AM and FM, and a radio device such as a TV. More particularly, the present invention relates to a small-sized antenna capable of transmitting and receiving two or more frequency bands having an even multiple relationship.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, an antenna for a wireless device such as a portable telephone is housed in a housing of a wireless device 31 when communication is not performed, and is removed from the housing during communication. A rod-shaped antenna 32 extending to the outside is used. The rod-shaped antenna 32 is formed so as to have a length of about ４ wavelength to about 波長 wavelength of a received signal. Therefore, when the frequency band to be received is determined, the length of the rod-shaped antenna is uniquely determined. Therefore, the length of an antenna for transmitting and receiving a signal in a low frequency band is inevitably increased. In order to shorten the external dimensions of the elongated rod-shaped antenna, a method of winding an antenna wire such as a piano wire in a coil shape and covering the outer periphery thereof with a resin or the like has been adopted.

On the other hand, the antenna of such a portable device is
It is housed inside the mobile device so that it does not get in the way when moving, and only a part of the antenna is installed to expose the outside of the mobile device to receive the ringing signal, or a separate antenna for receiving the ringing signal is mounted. During communication, the entire antenna is provided so as to extend out of the portable device. As a result, a paging signal can be received, and at the time of communication, communication can be performed with increased sensitivity.

Therefore, an antenna for receiving a paging signal needs to have a length of about 1/4 to about 1/2 wavelength of the received signal by itself. On the other hand, it is necessary that the antenna is small so as not to be in the way when being carried. Preferably, the antenna is usually wound in a coil shape to shorten the external length of the antenna. Also, the antenna at the time of communication is too long if the frequency band of the signal to be received is too low, which is inconvenient to handle, and the antenna for communication is also shortened in a coil shape.

[0005]

As described above, when the antenna is formed in a coil shape in order to reduce the length as an outer shape, when the coil interval is large, there is little electrical problem, but if the coil interval is sufficiently short, However, when the coil interval is narrowed (the coil is densely wound), the antenna length is shortened. However, there is a problem that the radiation resistance of the antenna is reduced and the antenna performance is deteriorated even when a matching circuit is additionally used.

Further, the length of the above-mentioned antenna is about 1/4.
In the case of wavelength length, about 3/4 for triple frequency band
Wavelength and function similarly to an approximately quarter-wave antenna.
Therefore, transmission and reception can be performed with the same antenna in an odd multiple frequency band such as three times or five times. But,
For a double frequency band, the wavelength is about 1/2 wavelength,
Unless a special matching circuit for two wavelengths is attached to the feeder side of the antenna, it will not function as an antenna. Cannot directly transmit and receive with the same antenna. Also, in the case of an antenna that is pulled out of the housing during communication and is extended, the length of the antenna to be pulled out is usually about 波長 wavelength, and for twice the frequency, it is reduced to 1 wavelength. In other words, since the phases are reversed every half-wavelength and cancel each other out, transmission and reception cannot be performed as they are for even-numbered frequency bands. However, in reality, for example, in portable telephones, GSM (Group Special)
Mobile) (PDC (Personal
(Corresponding to digital cellular)), the frequency of 900 MHz band is used, and DCS (digital cellular system) (corresponding to PHS (personal handy phone on system in Japanese system)) is 1800 MHz.
Preferably, frequencies in the z-band are used and both can be transmitted and received. Conventionally, in order to transmit and receive both, two antennas are separately provided, or an antenna wire is connected to the tip of the antenna for the high frequency band via a trap and further connected to an antenna line to match the length of the low frequency band. Must be used as

The present invention has been made to solve such a problem, and is an antenna which needs to be miniaturized, such as an antenna for transmission / reception of a portable device, and has a reduced outer dimension. It is an object of the present invention to provide an antenna capable of receiving a call signal by an antenna unit and extending the second antenna unit from a housing at the time of communication so that communication can be performed with high sensitivity.

Another object of the present invention is to provide a low frequency band signal for a signal in a frequency band such as an even multiple other than an odd multiple of the low frequency band, such as a low frequency band and a double frequency band. It is an object of the present invention to provide an antenna capable of transmitting and receiving simultaneously with one signal with one signal.

[0009] Still another object of the present invention is to provide a second communication method for communication.
Another object of the present invention is to provide an antenna which can shorten the total length thereof even when the antenna is extended, and can easily put the second antenna in and out.

[0010]

SUMMARY OF THE INVENTION The present inventors have made it possible to reduce the size of an antenna portion of a portable device or the like that can receive a call signal when the antenna is stored for movement without adding a special matching circuit. In order to obtain an antenna that does not degrade the performance, it is necessary to use a small
Intensive studies have been made to obtain an antenna capable of transmitting and receiving signals in the above frequency bands. As a result, by bending the antenna element so as to be substantially parallel along the long (axial) direction, if the number of times of bending is about 1 to 6 times, for example, a first frequency band of about 900 MHz is applied. In this case, the electrical length of the antenna element does not change so much, it acts as an antenna having a preset length of 1/4 wavelength, and the electrical length changes greatly for the second frequency band which is twice as high. Act as a / 4 wavelength antenna,
It has been found that by adjusting the number of times of return and the interval thereof, it is possible to transmit and receive signals in two or more desired frequency bands that are not odd-numbered frequencies.
No. 6 discloses this.

However, if the second antenna unit is extended from the housing to the outside and connected to the first antenna unit configured as described above in order to increase the sensitivity at the time of communication, for example,
When transmitting and receiving in the frequency band of
When the second antenna unit is configured to have an electrical length of about 波長 wavelength, the first antenna has an electrical length of ４ wavelength.
The phase is reversed with respect to the electrical length portion of the 2/4 wavelength of the antenna section, and the sensitivity is reduced. Further, also in the second antenna section, the first frequency band having a low frequency and the second frequency
When transmitting and receiving both frequency bands, if the wavelength is １ ／ wavelength for the first frequency band, it becomes one wavelength for the second frequency band, and the phase is also changed every 波長 wavelength. It reverses and sensitivity decreases.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the outer dimensions are shortened by being bent in the above-described axial direction. A first antenna unit capable of transmitting and receiving both of the double frequency band and a second antenna unit extending from the housing to improve the sensitivity at the time of communication or the like. It is characterized in that a means for coupling the second antenna section or a means for transmitting and receiving signals in two or more frequency bands having an even multiple relationship with the second antenna section is provided.

[0013] The antenna according to the present invention is mounted on a housing, and is folded at least once so that an antenna element made of a long conductor is substantially parallel along the long direction to form a folded portion. The first antenna unit is electrically separated from the first antenna unit when housed in the housing, and one end of the first antenna unit extends from the housing to the outside. And a second antenna section electrically connected to the first antenna section. The first antenna section is adjacent to the first antenna section by folding the antenna element.
Adjust the spacing and / or the number of folds of elements
As a result, the electrical length of the entire first antenna section becomes substantially １ ／ wavelength with respect to the first frequency band , and the second antenna section is almost twice as long as the first frequency band. For the frequency band, the first antenna unit is formed so that its electrical length is substantially ／ wavelength, and the second antenna unit is provided for the second frequency band. A first antenna element having an electrical length substantially equal to a half wavelength, and electrically connected to the first antenna element;
The entire second antenna section includes a second antenna element formed so as to have substantially a half wavelength with respect to the first frequency band.

Here, "substantially parallel" does not mean completely parallel, but means that the antenna elements are folded back so that they can be capacitively and / or inductively coupled between adjacent antenna elements. Further, the long direction means a direction in which the electromagnetic wave propagates mainly along the conductor. In addition, the electric length is substantially 1/4 wavelength, which is a length that can resonate at about 1/4 wavelength after the bent portion or the like is formed, and the R component and L component of the housing and various fittings to be attached. It means the length finely adjusted by cut and try due to the influence of the component. Actually, if the length is set to 1/4 wavelength or less, resonance can occur at about 1/4 wavelength due to line capacitance or the like. Substantially 3 /
Four wavelengths and substantially one-half wavelength have the same meaning. Furthermore, in addition to connection by conductor contact,
The meaning includes a conductor and a conductor that are capacitively and / or inductively coupled and connected.

The first antenna element and the second antenna element are connected to each other via a trap that performs parallel resonance with respect to a second frequency band, so that a second antenna element is provided.
For the frequency band of, the second antenna element portion above the trap does not electrically operate, and thus operates with a length of 波長 wavelength. In addition, since the trap has no effect on the first frequency band, signals in both frequency bands can be transmitted and received with high sensitivity.

Also, the first and second antenna elements are connected via a phase shifter which is 180 ° out of phase with respect to the second frequency band, so that both elements are in phase and have a half wavelength. Are connected in series, and the sensitivity is greatly improved.

The first antenna portion has a coupling turn-up portion at an electrical length of substantially 1/4 wavelength of the second frequency band from one end on the feeder side, and the coupling turn-up portion and the coupling turn-up portion are provided. First
Even if the second antenna unit is disposed so as to be capacitively and / or inductively coupled to both the other end of the antenna unit and the second antenna unit, both of the first and second frequency bands are Electrical connection between the first and second antenna units can be efficiently performed.

According to another aspect of the antenna of the present invention, there is provided a first antenna portion which is formed to have an electrical length of substantially 3/4 wavelength for one frequency band and is attached to a housing; Is formed so as to act as an electrical length of substantially 波長 wavelength as a whole, and is electrically separated from the first antenna portion when housed in the housing, and is externally connected to the housing. A second antenna portion, one end of which is electrically connected to and connected to an end of the first antenna portion on the side opposite to the power supply portion when the first antenna portion is extended. parts are in a portion corresponding to the electrical length of 2/4 wavelength of the frequency band from an end portion to which the second antenna unit are connected
In the current part of the same size, the direction of the current is opposite
The folded portions are formed so as to face each other, and the electric fields of the portions corresponding to the electric length of the ／ wavelength cancel each other out to act as a phase shifter. As a result, even if the first antenna section and the second antenna section are connected by direct electrical contact, the electric length portion of the 2/4 wavelength becomes a phase shifter, and is about 1/4 of the first antenna section. The electrical length portion of the wavelength and the electrical length portion of about a half wavelength of the second antenna portion have the same phase, and a high-sensitivity antenna that reinforces each other is obtained. The phrase “acts as an electrical length of substantially 波長 wavelength with respect to the frequency band as a whole” includes a case in which a tip portion is separated from the frequency band by a trap or the like and the portion does not operate as an antenna. And a case in which two portions operating as a half wavelength are connected via a phase shifter, and the two portions are in phase with each other and function as a half wavelength antenna as a whole.

[0019] Yet another embodiment of the antenna of the present invention, housing
Attached to the body, a first antenna portion folded portion is folded at least once so as to be substantially parallel is formed by an antenna element consisting of an elongated conductor along the longitudinal direction, the housing The first when stored in the body
The antenna portion is electrically separated consists of a second antenna portion having one end portion is connected to the first antenna portion electrically when it is extended to the outside from the housing, the second Is a series resonant circuit having an inductor element and a capacitor element, and is capacitively and / or inductively coupled to the first antenna section. As a result, the second antenna unit can be formed very small, and the extension and storage of the second antenna unit can be easily performed with a push button.

The first antenna section is formed with the folded section so as to be able to transmit and receive both the first frequency band and the second frequency band, and the second antenna section is connected in series in the first frequency band. A first series resonant circuit that resonates and a second
A second series resonance circuit that performs series resonance in the following frequency band, and each of the first and second series resonance circuits is capacitively and / or inductively coupled to the first antenna unit. Two or more frequency bands can be transmitted and received with a short antenna.

[0021]

Next, an antenna according to the present invention will be described with reference to the drawings.

FIG. 6 is a diagram for explaining the basic structure of the antenna disclosed in the above-mentioned Japanese Patent Application No. 8-160016.
In FIG. 6, reference numeral 1 denotes an antenna element made of a long conductor such as a piano wire, a strip-shaped conductive plate or a thin film, and one end of which is connected to a power supply portion of a connector 3 via a housing 2 of a portable device or the like. 3a, and the power supply unit 3a
Are connected to a transmitting / receiving circuit (not shown) by a cord 4. As shown in FIG. 6, the antenna is folded so as to be substantially parallel along the longitudinal direction of the antenna element 1, and a folded portion 1a is provided.

As described above, the present inventors have found that the antenna element 1 is bent so as to be substantially parallel along its longitudinal direction as shown in FIG.
It has been found that resonance is possible even in a frequency band such as an even multiple other than an odd multiple of a certain frequency band. That is, for example, the above-mentioned folded portion 1a is formed adjacent to the antenna element 1 formed to have an electrical length of about _１ ／ wavelength of a certain frequency band f1 (substantial meaning, the same applies hereinafter). Capacitive coupling between the antenna elements 1 and even mode (ev
en) and the odd mode (odd), etc., the electrical length does not change much for the frequency band f _1, whereas for an even multiple such as 2 times or in the vicinity thereof, It has been found that the electric length can be greatly changed by adjusting the number of turns and the distance between the antenna elements due to the turn.

The basic structure of the antenna will be described in more detail with reference to FIG. The antenna element 1 has a total length A + B + C (a,
b is very small and can be ignored), but is formed so as to have an electrical length of about 波長 wavelength of the _first frequency band f1, which is the lowest frequency band of the signal to be transmitted and received. In the example shown in FIG. 6, the antenna element 1 has two folded portions 1a and is folded in three. The lengths A, B, and C in the longitudinal direction of each folded into three are:
The distances a and b are almost equal, and as described above, for example, the second frequency band f ₂ (= 2) which is twice the _first frequency band f _1.
f ₁ ) is adjusted to resonate. The intervals a and b are almost the same, but are smaller than the lengths A, B, and C in the longitudinal direction, and the length is negligible.

The spacing a, by adjusting the number of b and folded, whereas unaffected electrical length less for the first frequency band f _1, a second frequency band f ₂ (= 2
For f ₁ ), the electrical length can be about ／ wavelength. This is the frequency band f ₁ (eg 900 MHz)
Is maintained without being affected by the bending of the antenna element 1 in order to maintain the matching state of １ ／ wavelength, while the antenna element is not affected by an even multiple of f ₁ or a frequency band near the same. This is considered to be because the electrical length changes depending on the capacitance between the 1 and the current direction due to the relationship between the even mode and the odd mode.

As described above, since the antenna element 1 is folded into three, the total length L of the antenna is reduced to about 1/3 of the 1/4 wavelength, and about 3 cm for the frequency of 900 MHz. Can be as short as possible. By further increasing the number of turns, the total length of the antenna can be further reduced.

The above-mentioned antenna element 1 may be a linear wire such as a copper wire or a piano wire, as shown in FIG. 6 by punching a metal plate, etching a thin film formed by vapor deposition or the like. The belt-shaped body (thin and wide) having a thin shape may be bent.

Further, as shown in FIG. 6, the bending direction of the antenna element 1 may be bent in the same direction on the same plane. For example, in FIG. 6, the third element piece (C Long element) may be folded three-dimensionally so as to be closer to and parallel to the other two element pieces on the front side of the drawing. In short, the antenna element 1 may be bent so that the direction in which the antenna element 1 is bent is substantially parallel to the longitudinal direction.

As described above, since this antenna is bent along its long direction, the long direction of the antenna element with respect to the plane of polarization of the electromagnetic wave is always constant, and the electrical length is an odd number of about 1/4 wavelength. If the length L is adjusted so as to be doubled, the length L of the outer shape of the entire antenna can be reduced without deteriorating the performance of the antenna without adding a matching circuit. However, in order to further reduce the length of the outer shape of the entire antenna, a coarse zigzag shape or a coil that does not deteriorate the antenna performance can be formed. An example is shown schematically in FIG.

FIGS. 7 (a) and 7 (b) show the antenna element 1 in which a zigzag pattern is formed in advance or a coil in which a rough coil is formed is folded in the longitudinal direction as shown in FIG. FIG. 7 (c) shows a roughly coiled antenna element 1 having a folded portion as shown in FIG. In any of the examples, by forming a coarse zigzag shape or coil that does not affect the radiation characteristics of the antenna, the overall length of the outer shape of the antenna can be shortened without being affected by the antenna performance.

Next, the above-mentioned folded antenna is used as a first antenna section, and a second antenna section extending from a housing at the time of communication is electrically connected to the first antenna section to a portable device such as a mobile phone. A suitable antenna of the present invention will be described in detail with reference to FIGS.

FIG. 1A is a conceptual diagram illustrating the structure of the antenna of the present invention. In FIG. 1A, reference numeral 10 denotes a first
At the antenna portion, as shown in Figure 6, the elongated conductor is bent along its longitudinal (axial) direction, by the folded portion is formed, for example, a first frequency band of 900MHz band Is formed so as to have an electrical length substantially equal to 1/4 wavelength (λ _L / 4) of the wavelength of 1800
The second frequency band of the MHz band is formed to have an electrical length of substantially ／ wavelength (3λ _H / 4). As a result, it is possible to transmit and receive both frequency bands of the first and second frequency bands, which are approximately doubled, and odd multiples of the respective frequency bands. Reference numeral 30 denotes a power supply unit.

Reference numeral 20 denotes a second antenna unit which is used for normal carrying.
Is housed in a housing (not shown),
To be electrically connected to the first antenna unit.
Thus, the sensitivity at the time of communication is improved. this
The second antenna section 20 is substantially equivalent to the second frequency band.
１ ／ wavelength (λ_H/ 2) The first antenna with an electrical length of
And the first antenna element 21
Connected to the first frequency band substantially substantially 1 /
Two wavelengths (λ_L/ 2) to make the electrical length
Antenna element 22 and an impedance connecting the two.
And a dance element 23. Such a configuration
As a result, as shown in FIG.
About 1/2 of the second frequency band by the antenna element 21
Wavelength (λ _H/ 2) operates as the antenna of the first and second antennas.
The second antenna elements 21 and 22 generate the first frequency.
About one-half wavelength (λ_L/ 2) Operates as an antenna
I do.

The first antenna element 21 and the second
1 is directly connected to the antenna element 22 of FIG.
As shown in (b), both the first and second antenna elements 21 and 22 have an electrical length of one wavelength (λ _H ) with respect to the second frequency band, and the phase is reversed as a whole. The sensitivity is reduced by canceling each other out. Therefore, in the present invention, the impedance element 23 is connected between the antenna elements 21 and 22.

The impedance element 23 includes an inductance L1 of an inductor element and a capacitance C1 of a capacitor element, for example, as shown in FIG. Trap 23a. By doing so, for the second frequency band, the trap 23a
Since the impedance becomes infinite, the portion of the second antenna element 22 is electrically separated and becomes irrelevant, and the antenna of the normal half wavelength (λ _H / 2) is formed only by the first antenna element 21. Becomes Also, the first
For the frequency band of, the trap 23 does not form a parallel resonance, so that the trap 23 does not perform the separating operation, and the first and second antenna elements 21 and 22 use the half wavelength (λ
_L / 2). This trap 23
a is an insulator 2 such as polyethylene, which covers a conductor 231 made of copper or the like as shown in FIG.
It is formed by winding a coil 233 around 32.

FIG. 3A is a diagram for explaining another example of the impedance element 23. In this example, the impedance element 23 is a phase shifter 23b that converts the phase of the second frequency band by 180 °. When represented by an equivalent circuit, the phase shifter 23b has an inductor element having an inductance L2 and a capacitor element having a capacitance C2 connected in parallel as shown in FIG. L2 and C2 are set so as to have an impedance corresponding to the wavelength, and the operation differs from that of the trap 23a. As a result, the phase is inverted at the phase shifter 23b, and the first and second antenna elements 21, 22 for the second frequency band have a current distribution as shown in FIG. 3B. , Both have the same phase. Therefore, also for the second frequency band, both antenna elements 21, 2
2 both operate as antennas, contributing to the antenna as a whole, and the sensitivity is greatly improved.

The electrical connection between the first antenna unit 10 and the second antenna unit 20 is different from that of the first antenna unit 10 when the second antenna unit 20 is extended from the housing. Capacitive and / or inductive coupling can be achieved by directly contacting and connecting to the other end, or by bringing the first antenna unit 10 and the second antenna unit 20 close to each other. When capacitively and / or inductively coupled, the coupling converts the phase by 180 °, and
When the first antenna unit 10 having the electrical length of the wavelength and the second antenna unit 20 having the electrical length of about 波長 wavelength are coupled, both phases become in-phase, and the two antennas reinforce to provide an antenna having good radiation characteristics. On the other hand, when the first antenna section 10 having an electrical length of about ４ wavelength and the second antenna section 20 having an electrical length of about 波長 wavelength are brought into direct contact and connected, the phase does not reverse at the connection point,
Since the phases are inverted in both antenna units, the sensitivity is slightly reduced. In view of these points, the following example provides a coupling structure of both antenna sections with high coupling efficiency.

First, when capacitively and / or inductively coupled, as shown in FIG. 4A, about 約 wavelength (λ _H / λ) of the second frequency band of the first antenna unit 10 is used.
In the electrical length part of 4), the connecting folded part 12 is provided,
For the second frequency band, the coupling fold 12 and the capacitance C
3 for the first frequency band, and the second antenna unit 20 is coupled to the end of the entire length (λ _L / 4) of the first antenna unit 10 via the capacitor C4. By arranging, the first and second antenna units 10 and 20 can be efficiently connected (coupled) to each other efficiently in the two phases with the same phase.

On the other hand, as shown in FIG.
When the first antenna unit 10 and the second antenna unit 20 are connected by making direct electrical contact with each other, the first antenna unit 10
If the electrical length is / 4 wavelength, the phase is inverted and the sensitivity is reduced as described above. On the other hand, the first antenna unit 10
Is an electrical length of about ／ wavelength, as shown in FIG. 4C, a change in current distribution indicates that the ２ wavelength (2λ) of the first antenna unit 10 for the second frequency band. _H / 4) and the half wavelength (λ _H /
The phase is reversed with part 2) and completely cancel each other out.
Does not function as a coupling antenna. Therefore, when connecting by direct contact, even if both antenna units 10 and 20 are connected as they are, it is not possible to cope with two frequency bands, and the sensitivity is reduced even for one frequency band. However, the first antenna unit 10 is formed so as to have an electrical length of about ／ wavelength, and the first antenna unit 10 is configured such that the electrical length portion of ２ wavelength acts as the phase shifter 11. By forming the folded portion, the characteristics can be improved. That is, as shown in the current distributions I1 and I2 in FIG. 4D, the currents of the 2/4 wavelength lines of the first antenna unit 10 having the same current magnitude are opposed to each other, and the directions of the currents are reversed. By forming the bent portion so as to be oriented (see the hatched portion in FIG. 4D), the 2/4 wavelength portion cancels the current and acts only as a phase shifter. As a result, even if the first antenna unit 10 and the second antenna unit 20 are directly contacted and connected, as shown in FIG. The electrical length portion and the electrical length portion of about a half wavelength of the second antenna portion 20 have the same phase, and the two antenna portions 10 and 2 having high coupling efficiency are used.
A bond of 0 is obtained. Therefore, antennas transmitting and receiving in one frequency band are connected to the first and second antenna units 10,
When the first antenna unit 10 is coupled by the direct connection of the first antenna unit 20, the first antenna unit 10 has an electric length of about 3/4 wavelength, and the bent portion is so formed that the electric length portions of 2/4 wavelength cancel each other as described above. It may be formed. 4C and 4E.
R, S and T in (b) indicate the locations of the positions R, S and T of the first antenna unit 10 in (b).

On the other hand, in the case where two antennas corresponding to two frequency bands are used by directly connecting the two antenna units 10 and 20 by direct connection, the total length is about に 対 し て wavelength of the electrical length of the first frequency band. In this frequency band, the electric length becomes about ／ wavelength, and the electric length portion of the 波長 wavelength forms a folded portion so as to cancel each other out as described above.
By doing so, an antenna having high coupling efficiency is obtained as described above for the second frequency band, and the first antenna unit 10 and the second antenna unit 2 are used for the first frequency band.
Although the phase is different at 0 and the sensitivity is slightly lowered, it does not completely cancel and can be used. In this case, the first antenna unit 10 is formed with a folded portion so as to function as a phase shifter with respect to the second frequency band. Has almost no component because the portion where the current is large is reversed and cancels out, but for the first frequency band, the current does not reverse in the same current value, and the power supply 30 Since the portion with the large current on the side is not canceled out, it functions as an antenna even when folded.

FIG. 5 shows that, even when the second antenna section is extended from the housing at the time of communication, the overall length of the antenna is still shortened.
FIG. 6 is an explanatory diagram of an antenna for allowing the antenna unit to be pulled out and stored with one touch. That is, in the example shown in FIG. 5, the second antenna unit 20 is configured by a closed-loop series resonance circuit including the inductor element 25 and the capacitor element 26. FIGS. 5A and 5B
In FIG. 5, reference numeral 10 denotes a first antenna unit, which is the same folded antenna as the antenna described in FIG. 6, and FIG. 5A is an antenna for transmitting and receiving only the first frequency band and an odd multiple frequency band thereof. FIG. 5B is an example of an antenna that can transmit and receive the first and second frequency bands that are in a double relationship, for example.

In FIG. 5A, the first antenna 1
0 means that the entire electrical length is substantially 1/1 of the first frequency band.
The second antenna unit 20 is formed to have an electrical length of four wavelengths, and the inductance L5 of the inductor element 25 and the capacitor element 2 are set so as to perform series resonance with the first frequency band.
By setting the closed-loop series resonance circuit 29 in which the value of the capacitance C5 of 6 is set, the first antenna unit 10 is substantially 1 as shown in FIG. Since resonance occurs at an electrical length of 波長 wavelength (λ / 4), the current flows to the maximum on the power supply unit 30 side. On the other hand, in the second antenna section 20, since the series resonance occurs in the first frequency band, the maximum current of the transmission / reception signal flows. Therefore, high-sensitivity transmission and reception can be performed by coupling the first antenna unit 10 and the second antenna unit 20 capacitively and / or inductively.

In FIG. 5B, the first antenna unit 1
Numeral 0 denotes an antenna having a folded portion formed so as to be able to simultaneously transmit and receive the first frequency band of the 900 MHz band and the second frequency band of the 1800 MHz band, for example. The second antenna section 20 includes an inductor element having an inductance of L6 and a capacitor element having a capacitance of C6. The first antenna element has a closed-loop first series resonance circuit 27 that performs series resonance in a first frequency band. , And a closed-loop second series resonance circuit 28 that performs series resonance in the second frequency band, each of which has a capacitance of C7 and a capacitance of C7. /
Alternatively, it is provided so as to be inductively coupled. In this case, providing the series resonance circuit 27 that performs series resonance in the first frequency band having a low frequency near the first antenna unit 10 can increase the capacitance C6.
The impedance is small for the second frequency band,
This is preferable because the connection between the series resonance circuit 28 and the first antenna unit 10 can be easily obtained.

Each of the series resonance circuits 27 to 29 is formed by winding a coil around an insulator such as polyethylene covering a conductor such as a copper wire as shown in FIG. 2B, for example. can do. Therefore, the length of the second antenna section can be formed as short as about 9 mm in total length, and the coil-shaped second antenna section as shown in FIGS. While it can be very short. As a result, as shown in FIG. 5D, the first antenna unit 10 is formed by the cylindrical insulator and the band-shaped antenna element 15 provided on the outer peripheral surface thereof, and the center thereof is By allowing the second antenna section 20 formed by a closed-loop series resonance circuit and having its periphery protected by resin or the like to be slidable, extension and storage operations can be easily performed with one hand with a push button or the like. it can.
Further, since the second antenna section 20 is very short, it does not hinder even if the second antenna section 20 is always connected to and fixed to the first antenna section without being taken in and out of the housing. By doing so, the reception sensitivity of the call signal is improved, and the transmission and reception can be performed with high sensitivity even during communication.

[0045]

According to the present invention, the folded antenna is the first antenna.
Since the second antenna unit is electrically connected at the time of communication, the call signal can be received by the small first antenna unit, and the second antenna unit can be connected at the time of communication. By using the antenna, a highly sensitive antenna can be obtained.

Furthermore, while forming the folded portion so that the first antenna can transmit and receive two frequency bands having a double relationship, the first antenna is not canceled out by the electrical connection with the second antenna portion. In addition, since the coupling and the coupling location are devised via a phase shifter, a trap or a phase shifter is used so that the element coupling of the second antenna unit is not canceled out in a double frequency band. , It is possible to transmit and receive any of the signals in the frequency band having a double relationship with high sensitivity.

Further, by using a series resonance circuit for the second antenna section, the second antenna section can be made very small, and the extension and storage of the second antenna section can be performed easily. The antenna can be made one-touch with a push button or the like, and can be made very short, so that a small antenna can be obtained so as not to be obstructed even when the antenna is always extended.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a relationship between first and second antenna units of the present invention and frequency bands.

FIG. 2 is an explanatory diagram of a coupling portion of an element of a second antenna unit according to the present invention.

FIG. 3 is an explanatory diagram of a coupling portion of an element of a second antenna unit according to the present invention.

FIG. 4 is an explanatory diagram of a coupling portion of the first and second antenna units of the present invention.

FIG. 5 is an explanatory diagram of an antenna in which a second antenna unit of the present invention is shortened.

FIG. 6 is a diagram illustrating a basic structure of a first antenna unit of the antenna according to the present invention.

FIG. 7 is a diagram showing a variation of the antenna of FIG. 6;

FIG. 8 is an explanatory diagram of an antenna attached to a conventional portable wireless device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 1st antenna part 11 Phase shifter 12 Folding part for coupling 20 2nd antenna part 21 1st antenna element 22 2nd antenna element 23 Impedance element 23a Trap 23b Phase shifter 27 1st series resonance circuit 28 Second series resonance circuit

Continuation of front page (72) Inventor Takao Kawahara 7-5-11 Takinogawa, Kita-ku, Tokyo Yokoo Co., Ltd. (56) References JP-A-5-243834 (JP, A) JP-A-48-11948 (JP) JP-A-5-121924 (JP, A) JP-A-5-136623 (JP, A) JP-A-62-1133409 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB Name) H01Q 1/12-1/26 H01Q 5/00-11/20

Claims (7)

(57) [Claims] 1. A first antenna mounted on a housing, wherein an antenna element formed of an elongated conductor is turned at least one turn so as to be substantially parallel along the elongated direction to form a folded portion. The antenna portion is electrically separated from the first antenna portion when housed in the housing, and one end thereof extends from the first antenna portion to the first antenna portion when extended from the housing to the outside.
Consists of a antenna portion and the second antenna portion electrically connected, the first antenna portion, said antenna Jer
The distance between adjacent elements is
By adjusting the number of times of folding , the electrical length of the entire first antenna unit becomes substantially １ ／ wavelength with respect to the first frequency band, and is substantially equal to the wavelength of the first frequency band. For the second frequency band, which is twice, the first antenna unit is formed so that its electric length is substantially ／ wavelength in the entire first antenna unit, and the second antenna unit is provided with the second antenna. A first antenna element whose electric length is substantially one-half wavelength with respect to a frequency band; and a first antenna element electrically connected to the first antenna element. And a second antenna element formed so as to have a substantially half wavelength with respect to the above frequency band. 2. The antenna according to claim 1, wherein the first antenna element and the second antenna element are connected via a trap that performs parallel resonance with respect to a second frequency band. 3. The antenna according to claim 1, wherein the first antenna element and the second antenna element are 180 degrees apart from each other in a second frequency band.
(2) connected via a phase shifter for shifting the phase.
The described antenna. 4. The coupling antenna according to claim 1, wherein the first antenna unit has a coupling fold at an electrical length of substantially １ ／ wavelength of a second frequency band from one end of the power supply unit. 4. The antenna according to claim 1, wherein the second antenna unit is disposed so as to be capacitively and / or inductively coupled to both the first antenna unit and the other end of the first antenna unit. 5. . 5. A first antenna unit which is formed to have an electrical length of substantially ／ wavelength for one frequency band and is attached to a housing, and substantially substantially as a whole for said frequency band. Is formed so as to function as an electrical length of 波長 wavelength, and is electrically separated from the first antenna portion when housed in the housing, and when the antenna is extended from the housing to the outside, A second antenna section, one end of which is electrically connected to an end of the first antenna section on the side opposite to the power supply section and which is connected to the second antenna section; Current of the same magnitude at a portion corresponding to an electrical length of 2/4 wavelength of the frequency band from the end to which the portion is connected
Turn the parts so that the current direction is opposite
An antenna in which a portion is formed and electric fields of a portion corresponding to the electrical length of the 波長 wavelength cancel each other to act as a phase shifter. 6. A first antenna mounted on a housing, wherein a folded portion is formed by folding at least one turn so that an antenna element made of an elongated conductor is substantially parallel along the elongated direction. An antenna unit , housed in the housing;
The first antenna portion is electrically separated from the first antenna portion when the first antenna portion is extended from the housing to the outside.
A second antenna unit electrically connected to the first antenna unit, the second antenna unit is a series resonance circuit having an inductor element and a capacitor element, and the second antenna unit is capacitively and / or electrically connected to the first antenna unit. Or an antenna that is inductively coupled. 7. The first antenna section is formed with the folded section so as to transmit and receive both a first frequency band and a second frequency band, and the second antenna section is provided with the first antenna section.
And a second series resonance circuit that performs series resonance in a second frequency band, wherein each of the first and second series resonance circuits is the first antenna. The antenna according to claim 6, which can be capacitively and / or inductively coupled to the part.