GB2350726A

GB2350726A - Retractable antenna

Info

Publication number: GB2350726A
Application number: GB0005889A
Authority: GB
Inventors: Yoshiyuki Ide
Original assignee: NEC Corp
Current assignee: NEC Corp
Priority date: 1999-03-12
Filing date: 2000-03-10
Publication date: 2000-12-06
Anticipated expiration: 2020-03-10
Also published as: GB2350726B; GB0005889D0; JP2000269714A

Abstract

An antenna for a mobile phone comprises a retractable whip element 7. A helical element 13 is attached to the top of whip 7 via an insulator 11. A further helical element 5 is fixed to the inside of the casing 1 of the mobile phone. When the whip is extended it is connected to the phone circuitry via helical element 5, and so both co-operate to form a fourth antenna element having an effective length of a quarter wavelength even when the whip antenna is shorter than this. In the retracted state (figure 5) the two helical elements 5, 13 are connected in series to form a fifth antenna element. Connections can be galvanic or capacitative (fig 15, 16, 17).

Description

2350726 TRANSCEIVER INCLUDING ANTENNA APPARATUS WHICH IS COMPACTLY

ACCOMMODATED IN BODY OF TRANSCEIVER

Background of the Invention 5 1. Field of the Invention

The present invention relates to a transceiver. More particularly, the present invention relates to a transceiver including an antenna apparatus which can be compactly accommodated in the body of the transceiver.

2. DescriDtion of the Related Art A bar or whip antenna can be used in a portable transceiver. At a time of transmission or reception, the whip antenna is pulled out from the body of the portable transceiver. During standby, the whip antenna is accommodated in the body of the portable transceiver. Electromagnetic waves are received by the whip antenna and processed by a signal processing circuit in the portable transceiver. Also, electromagnetic waves generated by the signal processing circuit are transmitted through the whip antenna.

It is necessary that the impedance of the antenna apparatus of the portable transceiver and the impedance of the signal processing circuit match with each other. Therefore, an impedance 2 matching circuit is used for converting the impedance of the signal processing circuit.

However, the impedance of the bar whip antenna when it is withdrawn is different from that when it is pulled out. For this reason, if the impedance of the whip antenna is matched with the impedance of the impedance matching circuit with each other in the condition that the whip antenna is pulled out from the body, it is impossible to match the impedance of the whip antenna and the impedance of the impedance matching circuit with each other in the condition that the whip antenna is accommodated in the body.

For this reason, an antenna apparatus is used in which a helical antenna is mounted at an end of a straight (bar) antenna. A portable transceiver containing such an antenna apparatus is disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 8-84017).

This known portable transceiver includes a body 101 and a bar antenna 102 as shown in Figs. 1 and 2. An end of the bar antenna 102 is inserted into the body 101. The bar antenna 102 includes a bar conductor 103, as shown in Fig. 3. The bar conductor 103 is covered with a dielectric sleeve 104. A conductive terminal 105 is connected to an end inserted into the body 101. The conductive terminal 105 is coupled to the conductor'103.

A dielectric 106 is coupled to the other end of the bar antenna 102, as shown in Figs. 1 and 2. An conductive connector 107 is coupled to the dielectric 106. A helical antenna 108 is coupled to the conductive connector 107. The helical antenna 108 is covered with a cover 109.

On the other hand, a slide terminal 110 is coupled to the body 101. The slide terminal 110 slidingly connects to the bar antenna 102. The slide terminal 110 is connected to the impedance matching circuit 111. The impedance matching circuit 111 is connected to the signal processing circuit 112. The impedance matching circuit 111 matches the impedance of the bar antenna 102 and the helical antenna 108 with that of the signal processing circuit 112. The signal processing circuit 112 processes electromagnetic waves received by the bar antenna 102 or the helical antenna 108. Moreover, the signal processing circuit 112 generates electromagnetic waves, and transmits the electromagnetic waves through the bar antenna 102 or the helical antenna 108.

The bar antenna 102 is used in an extended state in a case of long distance communication, as shown in Fig. 1. In the condition when the bar antenna 102 is extended, the conductive terminal - 4 is connected to the slide terminal 110. The bar antenna 102 transmits or receives the electric wave. The bar antenna 102 is used in the withdrawn state in a case of short distance communication, as shown in Fig. 2. In the condition that the bar antenna 102 is withdrawn, the conductive connector 107 is connected to the slide terminal 110. The helical antenna 108 transmits or receives electromagnetic waves. The known portable transceiver receives electromagnetic waves with the impedance being matched, in the case of both the withdrawn antenna and the extended antenna.

In order to increase the gain, it is necessary that the effective height of the helical antenna 108 is equal to or greater than one quarter of a wave length of the electromagnetic waves received by the helical antenna 108. Thus, a number of loops of the helical antenna 108 are required such that the effective height becomes equal to-or greater than about one quarter of the wave length of the electromagnetic waves. The helical antenna 108 needs to have a considerable size in accordance with the number of loops.

Other portable transceivers are disclosed in Japanese Laid Open Patent Application (JP-A-Heisei 7- - 5 131220, JP-A-Heisei 7-122917 and JP-A-Heisei 7 336122) and Japanese Patent Gazette (JP-B 2503856).

A portable transceiver is desirable in which the antenna is compact and the gain characteristic of the antenna is excellent when it is accommodated in the transceiver body.

Summary of the Invention

The invention is defined in the independent claims below, to which reference should now be made. Advantageous features are set forth in the appendant claims.

In a preferred embodiment of the present invention, a transceiver includes a body, a first antenna fixed to the body, a bar antenna, an insulating section coupled to the bar antenna and a second antenna coupled to the insulating section. The bar antenna can be accommodated in the body. The first and second antennas are electrically connected to form a third antenna when the bar antenna is accommodated in the body.

Desirably, the third antenna has an effective height larger than one quarter of a wave length of an electromagnetic wave received by the third antenna.

The bar antenna may be electrically connected to the first antenna to form a fourth antenna when the bar antenna is pulled out of the body. In this case, the third and fourth antennas 5 have substantially the same impedance.

The bar antenna and the second antenna may have substantially the same impedance.

Desirably, the fourth antenna has an effective height larger than one quarter of a wave length of electromagnetic waves received by the fourth antenna. The first and second antennas may be capacitively connected to form the third antenna when the bar antenna is accommodated in the body. 15 In this case, the second antenna may include a conductive portion. And the first antenna and the conductive portion may form a capacitance when the bar antenna is accommodated in the body. 20 The first antenna and the bar antenna may be capacitively connected to form the fourth antenna when the bar antenna is pulled out of the body. In this case, the bar antenna may include a second conductive portion. And the first antenna and the second conductive portion may form a capacitance when the bar antenna is pulled out of 7 the body.

The transceiver may further include a first conductive terminal coupled to the first antenna and a second conductive terminal coupled to the second antenna. In this case, the first conductive terminal has a first contacting surface. The second conductive terminal has a second contacting surface. The first conductive terminal contacts the second conductive terminal on the first and second contacting surfaces when the bar antenna is accommodated in the body.

The transceiver may further include a third conductive terminal coupled to the first antenna and a fourth conductive terminal coupled to the bar antenna. The third conductive terminal has a third contacting surface. The fourth conductive terminal has a fourth contacting surface. The third conductive terminal contacts the fourth conductive terminal on the third and fourth contacting surfaces when the bar antenna is pulled out of the body The first antenna may include a helical antenna.

The second antenna may include a second helical antenna.

A preferred radio receiver includes a body, a first antenna fixed to the body, a bar antenna, an insulating section coupled to the bar antenna and a second antenna coupled to the insulating section. The bar antenna can be accommodated in the body. The first and second antennas are electrically connected to form a third antenna when the bar antenna is accommodated in the body.

A preferred radio transmitter includes a body, a first antenna fixed to the body, a bar antenna, an insulating section coupled to the bar antenna and a second antenna coupled to the insulating section. The bar antenna can be accommodated in the body. The first and second antennas are electrically connected to form a third antenna when the bar antenna is accommodated in the body.

A preferred method of using a portable terminal includes pushing a bar antenna section into a portable terminal such that the bar antenna section is accommodated in a body of the portable terminal, a first antenna section protruding from the body and the first antenna section and a second antenna section in the body forming a first antenna and pulling out the bar antenna section from the body in transmission such that the bar antenna section and the second antenna section form a second antenna. 5 The method may further include receiving an electromagnetic wave in a state in which the bar antenna section is pushed into the portable terminal. The first and second antennas desirably have substantially same impedance.

Brief Description of the Drawings

Fig. 1 shows structure of a known portable transceiver, and shows structure in condition that a bar antenna 102 is extended; Fig. 2 shows structure of the known portable transceiver, and shows structure in condition that the bar antenna 102 is accommodated; Fig. 3 shows a section of the bar antenna 102 of the known portable transceiver; Fig. 4 shows structure in condition that a bar antenna 7 of a portable transceiver in a first embodiment is extended; Fig. 5 shows structure in condition that the bar antenna 7 of the portable transceiver in the first embodiment is accommodated; Fig. 6 shows structure in condition that the bar antenna 7 of the portable transceiver in the first embodiment is extended; Fig. 7 shows structure in condition that the bar antenna 7 of the portable transceiver in the first embodiment is accommodated; Fig. 8 shows structure in the vicinity of an end of the bar antenna 7 of the portable transceiver in the first embodiment; Fig. 9 shows structure in condition that a bar antenna 7 of a portable transceiver in a second embodiment is extended; Fig. 10 shows structure in condition that the bar antenna 7 of the portable transceiver in the second embodiment is accommodated; Fig. 11 shows structure in condition that the bar antenna 7 of the portable transceiver in the second embodiment is extended; Fig. 12 shows structure in condition that the bar antenna 7 of the portable transceiver in the second embodiment is accommodated Fig. 13 shows structure of the bar antenna 7 of the portable transceiver in the second embodiment; 25 Fig. 14 shows structure in condition that a bar antenna 7 of a portable transceiver in a third embodiment is extended; Fig. 15 shows structure in condition that the bar antenna 7 of the portable transceiver in the third embodiment is accommodated; Fig. 16 shows structure in condition that the bar antenna 7 of the portable transceiver in the third embodiment is extended; Fig. 17 shows structure in condition that the bar antenna 7 of the portable transceiver in the second embodiment is accommodated; and Fig. 18 shows structure of the bar antenna 7 of the portable transceiver in the third embodiment.

Description of the Preferred Embodiments

Portablp- transceivers embodying the present invention will be described below with reference to the attached drawings. A portable transceiver of a first embodiment in the present invention includes a body as shown in Figs. 4 and 5. A body 1 has a hole 2 as shown in Figs-6 and 7. A conductive ring terminal 3 is fixed to the body 1. The conductive ring terminal 3 has a hole 4. The hole 4 is indicated by dashed lines in Figs. 6 and 7. The hole 4 is coupled to the hole 2. A fixed helical antenna 5 is coupled to the conductive ring terminal 3. The fixed helical antenna 5 is accommodated within the body 1.

A resin sleeve 6 is further coupled to the body 1. The conductive ring terminal 3 and the fixed helical antenna 5 are fixed to the resin sleeve 6. As for the body 1 and the resin sleeve 6, the structures of the sections of them are shown in Figs. 4 to 7. The resin sleeve 6 has a hole 6a in the opposite side of the conductive ring 3.

A bar antenna 7 is inserted into the hole 2 mounted in the body 1. The bar antenna 7 further penetrates the hole 4 mounted in the conductive ring terminal 3. The bar antenna 7 can be accommodated in the body 1. The bar antenna 7 penetrates loops of the fixed helical antenna 5 when the bar antenna 7 is accommodated in the body 1. In addition, the bar antenna 7 penetrates the hole 6a when the bar antenna 7 is accommodated in the body 1.

The bar antenna 7 includes a bar conductor 8 as shown in Fig. 8. The bar conductor 8 is a portion for transmitting and receiving electromagnetic waves. The bar conductor 8 is covered with a dielectric sleeve 9. The dielectric sleeve 9 slides on the inner surface of the hole 4 of the conductive ring terminal 3. The dielectric sleeve 9 also slides on the inner surface of the hole 6a of the dielectric sleeve 6.

A conductive terminal 10 is mounted at an end of the bar antenna 7. The conductive terminal 10 is coupled to the conductor 8. The conductive terminal 10 contacts the inner surface of the hole 4 of the conductive ring 3 when the bar antenna 7 is pulled out from the body 1 to a maximum.

An insulating section 11 is coupled to the other end of the bar antenna 7. A conductive terminal 12 is coupled to the insulating section 11. The insulating section 11 insulates the conductor 8 and the conductive terminal 12 from each other. A tip helical antenna 13 is connected to the conductive terminal 12. The tip helical antenna 13 is covered with a cover 14. As for the cover 14, the structure of the section of the cover 14 is shown in Figs. 4, 5 and 7.

Moreover, wiring 15 is connected to the fixed helical antenna 5. The wiring 15 is connected to an impedance matching circuit 16. The impedance matching circuit 16 is connected to the signal processing circuit 17. The impedance matching circuit 16 matches the impedance of the signal processing circuit 17 with the impedance of theantenna portion composed of the fixed helical antenna 5, the bar antenna 7 and the tip helical antenna 13. The signal processing circuit 17 - 14 carries out a signal process for transmission and reception.

The impedance measured from the wiring 15 when the conductive terminal 10 contacts with the conductive ring terminal 3 after the extension of the bar antenna 7 is substantially equal tothe impedance measured from the wiring 15 when the conductive terminal 12 contacts the conductive ring terminal 3 after the accommodation of the bar antenna 7 in the body 1. This is attained by making the impedance of the bar antenna 7 substantially equal to that of the tip helical antenna 13.

Also,thesum of theeffective height of the fixed helical antenna 5 and theeffective height of the tip helical antenna 13 is larger than one quarter of a wave length of the electromagnetic waves which are transmitted and received by them.

The portable transceiver of the first embodiment in the present invention operates as follows.

The bar antenna 7 may be extended (pulled out), when the transceiver transmits an electromagnetic wave. When the bar antenna 7 is extended, the conductive terminal 10 connected to the conductor 8 is electrically connected through the conductive ring terminal 3 to the fixed - is helical antenna 5, as shown in Figs. 4 and6. The fixed helical antenna 5 is electrically connected through the wiring 15 to the impedance matching circuit 16.

At this time, the tip helical antenna 13 is electrically insulated from the conductive ring terminal 3. When the bar antenna 7 is extended, the conductive ring terminal 3 and the conductor 8 function as an antenna. The effective height of the antenna is larger than one quarter of the wave length of the electromagnetic waves which are transmitted and received by the antenna.

The bar antenna 7 may be accommodated. when the transceiver waits to receive an electromagnetic wave. When the bar antenna 7 is accommodated in the body 1, the tip helical antenna 13 is electrically connected through the conductive terminal 12 and the conductive ring terminal 3 to the fixed helical antenna 5, as shown in Figs. 5 and 7. The fixed helical antenna 5 is electrically connected through the wiring 15 to the impedance matching circuit 16.

At this time, the bar antenna 7 is electrically insulated from the fixed helical antenna 5. When the bar antenna 7 is extended, the conductive ring terminal 3 and the tip helical antenna 13 function as another antenna.

The effective height of the antenna is larger than one quarter of a wave lengthof the electromagnetic waves whichare transmitted and received by the antenna.

In the portable transceiver of the first embodiment, when the bar antenna 7 is accommodated in the body 1, the tip helical antenna 13 and the fixed helical antenna 5 within the body 1 operate as an antenna. Even ifthetip helical antenna 13 has a short axis, the effective height of the antenna portion can be more than one quarter of the wave length of the electromagnetic waves used for the communication. In the portable transceiver of the first embodiment, the tip helical antenna 13 can be miniaturized.

In succession, a portable transceiver of a second embodiment in the present invention is described. The structure of the portable transceiver of the second embodiment is similar to that of the portable transceiver of the first embodiment. The structure of the second embodiment is different in the connection mechanism between the f ixed helical antenna 5 and the conductor 8 and the connection mechanism between the f ixed helical antenna 5 andthe tip helical antenna 13, from the portable transceiver of the first embodiment.

The portable transceiver of the second embodiment has a body. As shown in Figs. 9and 10, a conductive ring terminal 18 is connected to the body 1. The conductive ring terminal 18 is exposed on surface of the body 1. An end of the fixed helical antenna 5 is coupled to the conductive ring terminal 18. The other end of the fixed helical antenna 5 is coupled to a conductive ring terminal 19. A resin sleeve 6 is further coupled to the body 1. The fixed helical antenna 5 is fixed to the resin sleeve 6.

As shown in Figs. 11 and 12, a hole 20 is formed in the conductive ring terminal 18. A hole 21 is formed in the conductive ring terminal 19. A bar antenna 7 is inserted through the hole 20, the fixed helical antenna 5 and the hole 21.

A conductive terminal 22 is coupled to an end of the bar antenna 7. The end coupled to the conductive terminal 22 is accommodated in the body 1. As shown in Fig. 13, the conductive terminal 22 is coupled to a conductor 8 contained in the bar antenna 7. The conductor 8 is covered with a dielectric sleeve 9. The conductive terminal 22 is cylinder-shaped. The conductive terminal 22 has a diameter larger than that of the hole 21. Thus, the bar antenna 7 is not detached from the body 1.

An insulating section 11 is coupled to an end outside the body 1, among the ends of the bar antenna 7. A conductive terminal 23 is coupled to the insulating section 11. The conductive terminal 23 is cylindershaped. The conductive terminal 23 has a diameter larger than that of the hole 20. The tip helical antenna 13 is connected to the conductive terminal 23. The tip helical antenna 13 is covered by a cover 14.

The conductive terminal 19 is connected to wiring 15. The wiring 15 is connected to an impedance matching circuit 16. The impedance matching circuit 16 is connected to a signal processing circuit 17. The impedance matching circuit 16 and the signal processing circuit 17 respectively function similarly to those contained in the portable transceiver of the first embodiment.

The impedance measured from the wiring 15 when the conductive ring terminal 19 contacts the conductive terminal 22 after the extension of the bar antenna 7 is substantially equal tothe impedance measured from the wiring 15 when the conductive ring terminal 18 contacts the conductive terminal 23 after the accommodation of the bar antenna 7 in the body 1. This is attained by making the impedance of the bar antenna 7 substantially equal to that of the tip helical antenna 13.

Also,thesum ofthe effective height of 5 the fixed helical antenna 5 and the ef f ective height of the tip helical antenna 13 is substantially one quarter of the wave length of electromagnetic waves whichare transmitted and received by them.

The portable transceiver of the second embodiment in the present invention operates as follows. When the bar antenna 7 is extended, surface 24 of the conductive ring terminal 19 contacts a surface 25 of the conductive terminal 22. The conductor 8 contained in the bar antenna 7 is electrically connected through the conductive terminal 22, the conductive ring terminal 19 and the wiring 15 to the impedance matching circuit 16. Also, the fixed helical antenna 5 is electrically connected through the conductive ring terminal 19 and the wiring 15 to the impedance matching circuit 16. The fixed helical antenna 5 and the conductor 8 form an antenna.

When the bar antenna 7 is accommodated in the body 1, a surface 26 of the conductive ring terminal 18 contacts a surface 27 of the conductive terminal 23. The tip helical antenna 13 is electrically connected through the conductive terminal 23 and the conductive ring terminal 18 to the fixed helical antenna 5. The fixed helical antenna 5 is electrically connected through the conductive ring terminal 19 and the wiring 15 to the impedance matching circuit 16. The fixed helical antenna 5 and the conductor 8 form another antenna.

In the portable transceiver of the second embodiment, the tip helical antenna 13 can be miniaturized similarly to the portable transceiver of the first embodiment. Moreover, the portable transceiver of the second embodiment has stable electric connection between the bar antenna 7 and the impedance matching circuit 16.

The reason is as follows. The conductive ring terminal 19 and the conductive terminal 22 are connected through the surfaces 24, 25 to each other. The surfaces 24, 25 are not mutually slid.

Theref ore, the contact between them is stable, which enables the electrical connection between the conductive ring terminal 19 and the conductive terminal 22 to be stable.

Also, the portable transceiver of the second embodiment has stable electric connection between the tip helical antenna 13 and the impedance matching circuit 16. This is because the surfaces 26, 27, through which the conductive ring terminal 18 and the conductive terminal 23 are connected, are not mutually slid.

In succession, a portable transceiver of a third embodiment in the present invention is described. The structure of the portable transceiver of the third embodiment is similar to those of the portable transceiver of the first embodiment and the portable transceiver of the second embodiment. The structure of the third embodiment is different in the connection mechanism between thef ixed helical antenna 5 and the conductor 8 and the connection mechanism between the-fixed helical antenna 5 andthetip helical antenna 13, from the portable transceivers of the first and second embodiments.

The portable transceiver of the third embodiment has a body. A resin sleeve 6 is coupled to its body 1 as shown in Figs. 14 and 15. The fixed helical antenna 5 is accommodated in the resin sleeve 6.

A hole 2 is formed in the body 1, as shown in Figs. 16 and 17. An end of the bar antenna 7 is inserted through loops of the fixed helical antenna 5 and the hole 2. The bar antenna 7 contains a conductor 8 as shown in Fig. 18. The conductor 8 is covered with a dielectric sleeve 9. The fixed helical antenna 5 and the conductor 8 are close to each other in the condition that the bar antenna 7 is extended from the body 1. The fixed helical antenna 5 and the conductor 8 form a considerable capacitance between them in the condition that the bar antenna 7 is extended from the body 1.

An insulating section 11 is coupled to the other end of the bar antenna 7. An end of a conductive terminal 29 is connected to the insulating section 11. The other end of the conductive terminal 29 is inserted into the tip helical antenna 13. The conductive terminal 29 and the tip helical antenna 13 are close to each other such that a considerable capacitance is generated between them. The tip helical antenna 13 is covered with a cover 14. In the conductive terminal 29, a length of a portion located outside the cover 14 and the tip helical antenna 13 is substantially equal to the axial length of the fixed helical antenna 5.

On the other hand, the fixed helical antenna 5 is connected to wiring 15. The wiring 15 is connected to an impedance matching circuit 16. The impedance matching circuit 16 is connected to a signal processing circuit 17. The impedance matching circuit 16 and the signal processing circuit 17 function similarly to those contained in the portable transceiver of the first embodiment.

The impedance measured from the wiring 15 when the end of the bar antenna 7 is inserted into the fixed helical antenna 5 after the extension of the bar antenna 7 is substantially equal tothe impedance measured from the wiring 15 when the conductive terminal 29 is inserted into the fixed helical antenna 5 after the withdrawal of the bar antenna 7 in the body 1. This is attained by adjustingthelength of the conductor 8 contained in the bar antenna 7 and the number of turns of the tip helical antenna 13.

Also,thesum of the effective height of the fixed helical antenna 5 and the effective height of the tip helical antenna 13 is substantially one quarter of thewave length of the electromagnetic waves which are transmitted and received by them.

The portable transceiver of the third embodiment operates as follows. When the bar antenna 7 is accommodated in the body 1, the conductive terminal 29 is inserted into the fixed helical antenna 5, as shown in Figs. 14 and 16. The fixed helical antenna 5 and the conductive terminal 29 become close to each other to accordingly generate a capacitance. The fixed helical antenna 5 and the conductive terminal 29 are electrically connected to each other in the frequency band of electromagnetic waves which the fixed helical antenna 5 and the tip helical antenna 13 transmit and receive. On the other hand, the tip helical antenna 13 and the conductive terminal 29 generate a capacitance between them, and are electrically connected to each other similarly to the fixed helical antenna 5 and the tip helical antenna 13. This results in that between the fixed helical antenna 5 and the tip helical antenna 13 is an electrical connection. The fixed helical antenna 5 is connected through the wiring 15 to the impedance matching circuit 16. At this time, the conductor 8 is insulated through the insulating section 11 from the fixed helical antenna 5. When the bar antenna 7 is accommodated in the body 1, the fixed helical antenna 5 and the tip helical antenna 13 function as an antenna.

When the bar antenna 7 is extended from the body 1, a part of the bar antenna 7 is inserted into the whole inside of the fixed helical antenna 5, as shown in Figs. 15 and 17. Capacitance is generated between the conductor 8 contained in the bar antenna 7 and the fixed helical antenna 5. The fixed helical antenna 5 and the conductor 8 are electrically connected to each other in the frequency band of the electromagnetic waves which they transmit and receive. At this time, the tip helical antenna 13 is electrically insulated through the insulating section 11 from theconductor 8. When the bar antenna 7 is extended, the conductive ring terminal 3 and the tip helical antenna 13 function as an antenna.

In the portable transceiver of the third embodiment, the tip helical antenna 13 can be miniaturized similarly to the portable transceivers of the first and second embodiments. Moreover, in the portable transceiver of the third embodiment, the electrical connection between the fixed helical antenna 5 and the conductor 8 is more stable than those of the portable transceivers of the first and second embodiments. This is because in the portable transceivers of the first and second embodiments, the conductors come in direct contact with each other, and are connected to each other. The direct contact between the conductors may disable the stable connection to be established. In the portable transceiver of the third embodiment, the fixed helical antenna 5 and the conductor 8 are electrically connected to each other without directly contacting. Thus, the electrical connection is stable.

Furthermore, in the portable transceiver of the third embodiment, the electrical connection between the fixed helical antenna 5 and the tip helical antenna 13 is stable due to the reason similar to the above-mentioned reason.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been changed in the details of construction and the combination and arrangement of parts may be resorted to without departing from the scope of the invention as hereinafter claimed.

Clalms: 1. An antenna apparatus comprising: a body; a first antenna fixed to said body; 5 a bar antenna, wherein said bar antenna can be accommodated in said body; an insulating section coupled to said bar antenna; and a second antenna coupled to said insulating section, wherein said first and second antennas are electrically connected to form a third antenna when said bar antenna is accommodated in said body.

2. An antenna apparatus according to claim 1, wherein said third antenna has an effective height larger than one quarter of the wave length of electromagnetic waves received by said third antenna.

3. An antenna apparatus according to claim 1, wherein said bar antenna is electrically connected to said first antenna to form a fourth antenna when said bar antenna is pulled out of said body and said third and fourth antennas have substantially same impedance.

4. An antenna apparatus according to claim 3, wherein said bar antenna and said second antenna have substantially same impedance.

5. An antenna apparatus according to claim 3, wherein said fourth antenna have an effective height larger than one quarter of the wave length of electromagnetic waves received by said fourth 5 antenna.

6. An antenna apparatus according to claim 1, wherein said first and second antennas are capacitively connected to form said third antenna when said bar antenna is accommodated in said 5 body.

7. An antenna apparatus according to claim 6, wherein said second antenna include a conductive portion and said first antenna and said conductive portion form a capacitance when said 5 bar antenna is accommodated in said body.

8. An antenna apparatus according to claim 6, wherein said third antenna has an effective height larger than one quarter of the wave length of electromagnetic waves received by said third 5 antenna.

9. An antenna apparatus according to claim 1, wherein said first antenna and said bar antenna are capacitively connected to form a fourth antenna when said bar antenna is pulled out of said body.

10. An antenna apparatus according to claim 9, wherein said bar antenna includes a second conductive portion and said first antenna and said second conductive portion form a capacitance when said bar antenna is pulled out of said body.

11. An antenna apparatus according to claim 9, wherein said fourth antenna has an effective height larger than one quarter of the wave length of electric waves received by said fourth antenna.

12. An antenna apparatus according t.o claim 1, further comprising: a first conductive terminal coupled to said first antenna, wherein said first conductive terminal has a first contacting surface; and a second conductive terminal coupled to said second antenna, wherein said second conductive terminal has a second contacting surface and said first conductive terminal contacts said second conductive terminal on said first and second contacting surfaces when said bar antenna is accommodated in said body.

13. An antenna apparatus according to claim 1, further comprising: a third conductive terminal coupled to said first antenna, wherein said third conductive terminal has a third contacting surface; and a fourth conductive terminal coupled to said bar antenna; wherein said fourth conductive terminal has a fourth contacting surface and said third conductive terminal contacts said fourth conductive terminal on said third and fourth contacting surfaces when said bar antenna is pulled out of said body.

14. An antenna apparatus according to claim 1, wherein said first antenna includes a helical antenna.

15. An antenna apparatus according to claim 1, wherein said second antenna includes a second helical antenna.

16. A transceiver comprising: an antenna apparatus according to any one of claims 1 to 15.

17. A radio receiver comprising: an antenna apparatus according to any one of claims 1 to 15.

18. A radio transmitter comprising: an antenna apparatus according to any one of claims 1 to 15.

19. A method of using an antenna apparatus comprising: pushing a bar antenna section into a portable terminal such that said bar antenna section is accommodated in a body of said portable terminal, a first antenna section protruding from said body and said first antenna section and a second antenna section in said body forming a first antenna; and pulling out said bar antenna section from said body in transmission such that said bar antenna section and said second antenna section form a second antenna.

20. A method according to claim 19, further comprising: receiving an electromagnetic wave in a state in which said bar antenna section is pushed into said portable terminal.

21. A method according to claim 19, wherein said first and second antennas have substantially same impedance.

22. An antenna structure substantially as any of the embodiments herein described with reference to Fig. 4 et seq. of the drawings.