Multi-band antenna of compact size

Description

[0001] The present invention relates to a monopole antenna of a compact size with a three-dimensional bending structure that uses a characteristic of coupling effectively between different frequency bands to improve the antenna's efficiency according to the precharacterizing clause of claim 1. Such an antenna is known from WO 02/29926 A1 and from US 2006/0181466 A1.

[0002] In a modern world of information, various wireless communication networks have become one of the most important channels for exchanging sounds, text, numerical results, data, and video for many people. An antenna is required to receive information carried by wireless electromagnetic waves in a wireless communications network. Therefore the development of antennas has also become one of key issues for vendors in the technology field. In order to have users implement and access information from different wireless networks in ease, an antenna with better design should be able to cover different bands of each wireless communications network with only one antenna. Besides, the size of the antenna should be as small as possible to be implemented in compact portable wireless devices (such as cellphones, Personal Digital Assistants i.e. PDAs).

[0003] This in mind, the present invention aims at providing a compact multi-band antenna for overcoming these problems.

[0004] This is achieved by a multi-band antenna according to claim 1. The dependent claims pertain to corresponding further developments and improvements.

[0005] As will be seen more clearly from the detailed description following below, the claimed multi-band antenna bends to form a three-dimensional structure comprising low/high frequency radiation portions effectively reducing space occupied by the antenna.

[0006] In the following, the invention is further illustrated by way of example, taking reference to the accompanying drawings. Thereof

Fig. 1 is a diagram of an antenna of the prior art;

Figs. 2-5 are diagrams of an embodiment of an antenna of the present invention from various perspectives;

Figs. 6-9 present different portions of the antenna in Fig. 2;

Fig. 10 presents frequency characteristics formed by an intercoupling effect of high/low frequency radiation portions of the antenna of the present invention;

Fig. 11 is a diagram of a voltage standing wave ratio (VSWR) of the antenna of the present invention in practice;

Fig. 12 is a diagram of the antenna in Fig. 2 installed on a circuit board;

Figs. 13-16 are diagrams of the antenna in Fig. 2 installed on a fixture;

Figs. 17-18 are diagrams of the antenna in Fig. 2 embedded in a circuit board; and

Figs. 19-23 and 26 present various embodiments of the antenna of the present invention respectively, and Figs. 24 and 25 are examples of a bended monopol antenna.

[0007] In the prior art, Planar Inverted-F Antennas (PIFAs) are the most popular for wireless communication network transceiving services. Please refer to Fig 1. Fig. 1 is a diagram of an antenna 10 that is a typical PIFA. A PIFA generally uses a planar radiation portion and a planar base to induce an electromagnetic wave oscillation. In addition, an antenna as shown in the R.O.C. patent publications number 200419843 (corresponding to U.S. patent US6,930,640) is also a type of PIFA. However, when using this type of antenna as a multi-band antenna, a planar radiation portion of the antenna requires a large planar area, and a distance between the radiation plane and a base plane of the antenna d0 (as in Fig. 1) is related to a frequency/bandwidth of the antenna that cannot be adjusted as desired. Thus, the antenna of the prior art cannot be structurally reduced in size and is unable to meet the needs of compactness and multi-band reception.

[0008] Please refer to Figs. 2-5. Figs. 2-5 are diagrams with different viewing angles of an embodiment 20 of an antenna of the present invention. The antenna of the present invention 20 can be a monopole antenna, with a coupling portion CP, a low frequency radiation portion L, and a high frequency radiation portion H to have the antenna of the present invention 20 functioning in multi-band and supporting different requirements from each frequency band of wireless communications. As shown in Figs. 2-5, the antenna 20 can be formed with bended conductors having uniform cross sections (for example, a copper wire having circular cross sections). The low frequency radiation portion L and the high frequency radiation portion H are extensions of different (opposite) ends of the coupling portion CP and hence form a three-dimensional structure. The coupling portion CP feeds-in or feeds-out signals with a signal feeding point S, the low frequency radiation portion L and the high frequency radiation portion H are for inducing radiation characteristics of low frequency and high frequency bands, so the antenna 20 of the present invention can cater to both low and high frequency bands in wireless communicational needs. In the embodiment shown in Figs. 2-5, the low frequency radiation portion L extends longer and can be bended at a plurality of bending points to form a plurality of sections along two non-parallel planes in a three-dimensional space, whereas the high frequency radiation portion H is shorter and can be bended at a single point to form two sections.

[0009] Along with the embodiment shown in Figs. 2-5, please refer to Figs. 6-9. Figs. 6-9 more clearly show and explain structures of each part of the antenna 20. As seen in Fig. 6 and Fig. 7, the low frequency radiation portion L of the antenna 20 bends along two non-parallel planes P1 and P2 (Fig. 6), and bends to form sections L1 to L5 (Fig. 7) at bending points L1p to L4p. The sections are three main (longer) sections L1, L3, and L5 and two shorter sections L2 and L4. Of the low radiation portions L1 to L5, the furthermost portion is L5, so L5 can be seen as a low radiation frequency portion of L. Furthermore, in Figs. 8 and 9, the high frequency radiation portion H of the antenna 20 bends along a plane P3 (Fig. 9) at a bending point H1p to form two sections H1, and H2 (Fig. 8) on a same plane. Within each section of the high frequency radiation portion H, the section that extends the furthest from the coupling portion CP is the section H2, so that the section H2 is recognized as a terminal section of the high frequency radiation portion H. Based on the structure of the antenna of the present invention in Fig. 9, it is known that other than a terminal section L5 being able to be on the same plane as each section of the high frequency radiation portion H (H1, H2), and at least one section of the other sections of the low frequency radiation portion L (L1 to L4) is on a different plane from the high frequency radiation portion H. Due to the structure of the antenna, a size of the present invention is effectively reduced and meets the requirements of compact portable communications devices.

[0010] As for the structure of the antenna 20 shown in Fig. 9, the terminal section L5 of the low frequency radiation portion L is parallel to the terminal section H2 of the high frequency radiation portion H, and the distance between the two terminal sections is d. To compare, distances between the terminal section H2 and other sections (like L1, L3) of the low frequency radiation portion L are larger than the distance d. Because the terminal sections of low and high frequency radiation portions are close and parallel to each other, the present invention is able to improve overall characteristics with couplings between the low and high frequency radiation portions.

[0011] Please refer to Fig. 10, which illustrates the theory of couplings between the low/high frequency radiation portions in a frequency spectrum according to the characteristics of the present invention. The horizontal axis represents frequency and the vertical axis represents frequency spectrum characteristics. For instance, the vertical axis can be VSWR (Voltage Standing Wave Ratio). For people who are familiar with the technique, a local minimum of the VSWR in a spectrum can represent a usable bandwidth of an antenna, so the VSWR is usually used to show a radiation characteristic of an antenna (especially in a frequency spectrum).

[0012] Fig. 10 presents that if only the low frequency radiation portion is considered, the low frequency radiation portion of the antenna with longer length induces a low frequency local minimum (shown in Fig. 10 with a broken line) at a low frequency band (i.e. around frequency f0). Similarly, taking only the high frequency radiation portion into account, with a shorter high frequency radiation portion, the antenna induces a high frequency local minimum (also represented with a broken line) around a frequency f2 at a high frequency band. In general, a bandwidth of the high frequency band can barely simultaneously support different working bands required by different high frequency communications (2G/3G applications). However, as discussed earlier, the antenna of the present invention is especially designed to have a stronger coupling between the low and the high frequency radiation portions, so overall characteristics of the antenna are improved with the intercoupling. The intercoupling causes two effects. First, the intercoupling promotes coupling of harmonics of the low frequency radiation portion and hence induces a local minimum at a harmonic frequency. Secondly, as presented in Fig. 10, a second harmonic of the low frequency radiation portion can induce another local minimum at a frequency f1 (meaning that the frequency f1 is about twice of the frequency f0), and this helps for expanding usable bandwidth of the high frequency band.

[0013] Besides, the intercoupling between the low/high frequency radiation portions can also produce equivalent intercoupled/autocoupled inductances and capacitances between each section. The inductance and capacitance lower a Q factor of the antenna accordingly to increase a bandwidth of frequency spectrum of the antenna. From Fig. 2 to Fig. 9, sections L1, L3, and L5 of the antenna 20 intercouple with the section H2 to form an intercoupled capacitance. Each section produces equivalent inductances from intercoupling/autocoupling (e.g., at bending points), and these inductive, capacitive effects can reduce the Q factor of the antenna 20. As the Q factor gets larger, the bandwidth gets smaller. Hence the decrease in Q factor reflects on the spectrum as the increase in bandwidth. As curves shown in Fig. 10, since the present invention increases bandwidth with intercoupling effects, the local minimums at frequencies f1 and f2 can expand while the Q factor decreases and combine with each other to form a usable band of high frequency and to fulfill requirements of different wireless communication networks.

[0014] In theory, the intercoupling between the high and low frequency radiation portions is actually interference, but the present invention takes advantages of this character and utilizes the intercoupling to expand the usable bandwidth so that the interference has turned to be an advantage of the antenna's performance. The present invention fine-tunes overall characteristics of the antenna of the present invention (e.g., a center frequency of the usable band and it bandwidth etc.) by changing a distance between the two terminal sections of the low/high frequency radiation portion (presented as a distance d in Fig.9) to change a degree of intercoupling between the two terminal sections and therefore achieves the fine-tuning process. For example, to increase the distance d (Fig. 9), a length of a section H1 can be reduced appropriately to reduce the intercoupling between the two terminal sections.

[0015] In application, the present invention uses sections having lengths around 3cm (or shorter) to support 5 different bands, including Global System for Mobile communication (GSM) 850/900, GSM 1800/1900, UMTS (Universal Mobile Telecommunications System) 2100. Supporting low frequencies of the GSM850/900 communications networks conventionally requires a low frequency radiation conductor around 9cm long. Due to the three-dimensional bended structure of the low frequency radiation portion of the present invention, the conductor only needs to be around 3cm (or shorter) to support GSM850/900 requirements. On the other hand, the present invention uses a wide bandwidth expanded by the intercoupling between the low/high frequency radiation portions and hence fully supports high frequency bands of GSM1800/1900 and UMTS 2100. For a more realistic description, please refer to Fig. 11. With an antenna structure design shown in Fig. 2, the present invention realistically practices a frequency spectrum characteristic as shown in Fig. 8 where the horizontal axis represents frequency and the vertical axis represents VSWR. From Fig. 11, the antenna supports GSM850/900 in low frequency band while covering GSM1800/1900 and UMTS 2100 in the high frequency wideband. With only one antenna, 5 different bands from different wireless communications requirements are met, therefore a multi-band antenna is achieved.

[0016] As the present invention is small in size and supports high frequency bands, it can be applied on various portable communications devices, like cellphone, Personal Digital Assistants (PDAs), or laptop computers etc.

[0017] Please refer to Fig. 12. To continue the example explained by Fig.2 to Fig. 9, Fig. 12 is a diagram of the antenna 20 installed on a circuit board 22 of the present invention. A signal feeding point of the antenna 20 is coupled to a corresponding circuit on the circuit board 22 (for instance, a printed circuit board) to receive feeding-ins and feeding-outs of signals. The antenna of the present invention can also be placed on fixtures in practice when installing the antenna on a communications device.

[0018] Please refer to Figs. 13-16. Figs. 13-16 are diagrams of different viewing points presenting an installation of the antenna 20 with a fixture 24. The fixture 24 can be a medium material (i.e. a non-conductive material such as plastic etc.). As shown in Figs. 13-16, the fixture 24 comprises various holes and rails to fit with the antenna structure of the present invention. When the fixture 24 and the antenna 20 are fixed together, it can be easily placed on a circuit board (not shown in Figs. 13-16). For example, the fixture 24 can comprise tenons, screw holes etc. to have the antenna/fixture combination fixed on the circuit board. The fixture 24 not only fixes/protects the three-dimensional structure of the antenna 20, but also can be used as a supporting pole for other communications devices (such as camera lens etc.) The material of the fixture 24 can affect the characteristics of the antenna 20. However, as explained earlier, the distance d (Fig. 9) between the low/high frequency radiation portions can be adjusted to fine-tune the characteristics and compensate effects of the fixture 24. In reverse, the characteristics or other radiation characteristics (like radiation field) of the antenna can also be adjusted, varied through tuning or changing the medium material of the fixture 24.

[0019] Other than fixing the antenna of the present invention on a surface of a circuit board as illustrated in Fig. 12, the antenna can also be fixed on a side of a circuit board to match with a fixture since the present invention has a three-dimensional structure, so that space occupied by the antenna is further reduced. Please refer to Figs. 17-18, which illustrate the antenna 20 embedded on a circuit board 28 with a fixture 26. As shown in Figs. 17-18, a structure of the fixture 26 corresponds to a thickness of the circuit board 28 to have the antenna 20 embedded in one side of the circuit board 28. Therefore, the antenna 20 with the three-dimensional structure is able to embed in and distribute in two different sides of a circuit board (meaning that different sections of the antenna 20 can be distributed on the two different sides of the circuit board 28) to reduce space taken by the antenna.

[0020] In the embodiment shown in Fig. 2 (to Fig. 9), the present invention is formed by constructing the conductor having a uniform cross section (circular cross section). With the structure of the present invention, other types of conductors can also be used to construct an antenna. Please refer to Fig. 19. Fig. 19 is another embodiment of an antenna 30 of the present invention. As illustrated in Fig. 19, the antenna 30 uses a bending stamp of a flat metal strip. Similar to the antenna 20 in Fig. 2, the antenna 30 in Fig. 19 also comprises a coupling portion CPa (with a signal feeding point Sa), a low frequency radiation portion La and a high frequency radiation portion Ha, to put the theory of a monopole multi-band antenna into practice. With the same idea, a distance da between the low frequency radiation portion La and the high frequency radiation portion Ha can also be adjusted to tune a radiation characteristic of the antenna 30.

[0021] Please refer to Figs. 20-21. Figs. 20-21 are diagrams with different viewing points of another embodiment of an antenna 40 of the present invention. Similar to the antenna 30 in Fig. 19, the antenna 40 in Figs. 20-21 is also formed with a bended flat metal strip, comprising a coupling portion CPb (with a signal feeding point Sb), a low frequency radiation portion Lb, and a high frequency radiation portion Hb. There is a difference that a main section (a longer section) of each section of the antenna 40 is curved. Even thus, terminal sections of the low frequency radiation portion Lb and the high frequency radiation portion Hb are still parallel to each other on a same curve plane and therefore increase intercoupling between the sections. The characteristics of the antenna 40 can be fine-tuned by changing the intercoupling through adjusting the distance db.

[0022] Please refer to Fig. 22 and Fig. 23. Fig. 22 and Fig. 23 present another two embodiments of antennas 50 and 60 of the present invention. In Fig. 22, the antenna 50 also comprises a coupling portion CPc (with a signal feeding point Sc), a low frequency radiation portion Lc, and a high frequency radiation portion Hc. The terminal sections of the low/high radiation portion are paralleled with a shorter distance between them to have a stronger intercoupling. In Fig. 23, the antenna 60 also comprises a coupling portion CPd (with a signal feeding point Sd), a low frequency radiation portion Ld, and a high frequency radiation portion Hd. The low frequency portion can only have one section, and the section is paralleled to a terminal section of the high frequency radiation portion to dominant an intercoupling between them.

[0023] Please refer to Figs. 24-25 and Fig. 26. Figs. 24-26 present another two embodiments of antennas 70 and 80 of the present invention. Figs. 24-25 illustrate the antenna 70 of the present invention from different views. The three-dimensional structure of the antenna in the present invention does not need to be distributed on planes that are perpendicular to each other. The antenna 70 shown in Figs. 24-25 distributes each section on planes that are not perpendicular to each other. The antenna 70 also comprises a coupling portion CPe (with a signal feeding point Se), a low frequency radiation portion Le and a high frequency radiation portion He. The low frequency radiation portion Le bends into several sections along a plane, and terminal sections of the low/high frequency radiation portions are also close to and paralleled to each other to have a strong intercoupling. The antenna 80 also comprises a coupling portion CPf (with a signal feeding point Sf), a low frequency radiation portion Lf, and a high frequency radiation portion Hf, where terminal sections of the low/high frequency radiation portions are also close to and paralleled to each other to have a strong intercoupling.

[0024] As the embodiments show in Fig. 19 to Fig. 23 and Fig. 26, the present invention can be formed with a conductor (for instance, the coupling portion and the low/high frequency radiation portions are formed with one bended metal having a uniform cross section), which saves time and money consumed in manufacturing. However, the antenna in the present invention can also be formed with different conductors, for example, different metal conductors with different cross sections forming low/high frequency radiation portions respectively, and combined to be an antenna with a conductor being a coupling portion.

[0025] In conclusion, compared with the prior art, the monopole antenna of the present invention bends to form a three-dimensional structure comprising low/high frequency radiation portions effectively reducing space occupied by the antenna. A controllable intercoupling between the low/high frequency radiation portions is established, with the intercoupling the overall characteristics and performance of the antenna are improved (for instance, increases the usable bandwidth of the antenna in high frequency bands). Therefore, the present invention, with a compact antenna, supports various low/high frequency bands to cater different needs from wireless communication networks.

Claims

1. A multi-band antenna (20) comprising:

a coupling portion (CP) for feeding-in or feeding-out signals;

a first radiation portion (L) coupled to one end of the coupling portion (CP) ; the first radiation portion (L) bended at one or more bending points (L1p, L2p, L3p, L4p) to form a plurality of sections (L1, L2, L3, L4, L5), wherein a terminal section (L5) being a section of the first radiation portion (L) extended furthest from the coupling portion (CP); and

a second radiation portion (H) coupled to another end of the coupling portion (CP); the second radiation portion (H) comprising at least two sections (H1, H2), wherein the terminal section (H2) of the second radiation portion (H) is parallel to the terminal section (L5) of the first radiation portion (L), in order to have radiation characteristics of the two parallel sections intercoupled for increasing a bandwidth of the multi-band antenna (20);

characterized in that

the first radiation portion is bended to form a first main section (L1), a second main section (L3) and the terminal section (L5); the first main section (L1) and the second main section (L3) defining a first plane (P1), the second main section (L3) and the terminal section (L5) defining a second plane (P2), the first plane (P1) and the second plane (P2) being not parallel to each other; and the distance (d) between the terminal section (H2) of the second radiation portion (H) and the terminal section (L5) of the first radiation portion (L) is smaller than a distance between the terminal section (H2) of the second radiation portion (H) and any other section of the first radiation portion (L).

2. The multi-band antenna (20) of claim 1 characterized in that the second radiation portion (H) is bended at one or more bending points (H1p) to form a plurality of sections.

3. The multi-band antenna (20) of claim 1 characterized in that some of the sections of the second radiation portion (H) are on a same plane as the terminal section (L5) of the first radiation portion (L).

4. The multi-band antenna (20) of claim 1 characterized in that the first radiation portion (L) is used for radiating electromagnetic waves in low frequency bands, the second radiation portion (H) is used for radiating electromagnetic waves in high frequency bands, so the multi-band antenna (20) supports transmitting and receiving of multi-band wireless signals.

5. The multi-band antenna (20) of claim 1 characterized in that the first radiation portion (L) and the second radiation portion (H) are formed with bended conductors having uniform cross sections.

6. The multi-band antenna (20) of claim 1 characterized in that the multi-band antenna (20) further comprises a fixture (24, 26) which comprises a medium material for protecting a structure of the multi-band antenna (20) or adjusting characteristics of the multi-band antenna (20).

7. The multi-band antenna (20) of claim 6, characterized in that the fixture (24, 26) allows the antenna (20) to be embedded on a circuit board (22, 28) so that different sections of the multi-band antenna (20) are distributed on both sides of the circuit board (22, 28).

Ansprüche

1. Eine Mehrbandantenne (20), umfassend:

- einen Koppelbereich (CP) zum Einspeisen oder Ausspeisen von Signalen;

- einen mit einem Ende des Koppelbereichs (CP) verbundenen ersten Abstrahlbereich (L); wobei der erste Abstrahlbereich (L) an einem oder mehreren Biegepunkten (L1p, L2p, L3p, L4p) gebogen ist, um eine Vielzahl von Abschnitten (L1, L2, L3, L4, L5) zu formen, wobei ein Abschlussabschnitt (L5) ein Abschnitt des ersten Abstrahlbereichs (L) ist, der sich am weitesten entfernt von dem Koppelbereich (CP) erstreckt; und

- einen mit einem anderen Ende des Koppelbereichs (CP) verbundenen zweiten Abstrahlbereich (H); wobei der zweite Abstrahlbereich (H) zumindest zwei Abschnitte (H1, H2) umfasst, wobei der Abschlussabschnitt (H2) des zweiten Abstrahlbereichs (H) parallel zu dem Abschlussabschnitt (L5) des ersten Abstrahlbereichs (L) ist, um Abstrahlcharakteristiken der zwei parallelen Abschnitte zum Erhöhen einer Bandbreite der Mehrbandantenne (20) miteinander zu verkoppeln;

dadurch gekennzeichnet, dass

- der erste Abstrahlbereich derart gebogen ist, um einen ersten Hauptabschnitt (L1), einen zweiten Hauptabschnitt (L3) und den Abschlussabschnitt (L5) zu formen; wobei der erste Hauptabschnitt (L1) und der zweite Hauptabschnitt (L3) eine erste Ebene (P1) definieren, der zweite Hauptabschnitt (L3) und der Abschlussabschnitt (L5) eine zweite Ebene (P2) definieren, die erste Ebene (P1) und die zweite (P2) nicht parallel zueinander sind; und der Abstand (d) zwischen dem Abschlussabschnitt (H2) des zweiten Abstrahlbereichs (H) und der Abschlussabschnitt (L5) des ersten Abstrahlbereichs (L) kleiner ist, als ein Abstand zwischen dem Abschlussabschnitt (H2) des zweiten Abstrahlbereichs (H) und jedem anderen Abschnitt des ersten Abstrahlbereichs (L).

2. Mehrbandantenne (20) nach Anspruch 1, dadurch gekennzeichnet, dass der zweite Abstrahlbereich (H) an einem oder an mehreren Biegepunkten (H1p) gebogen ist, um eine Vielzahl von Abschnitten zu formen.

3. Mehrbandantenne (20) nach Anspruch 1, dadurch gekennzeichnet, dass einige der Abschnitte des zweiten Abstrahlbereichs (H) in einer selben Ebene liegen, wie der Abschlussabschnitt (L5) des ersten Abstrahlbereichs (L).

4. Mehrbandantenne (20) nach Anspruch 1, dadurch gekennzeichnet, dass der erste Abstrahlbereich (L) zum Abstrahlen von elektromagnetischen Wellen in niedrigen Frequenzbändern verwendet wird, der zweite Abstrahlbereich (H) zum Abstrahlen von elektromagnetischen Wellen in hohen Frequenzbändern verwendet wird, so dass die Mehrbandantenne (20) das Aussenden und Empfangen von Mehrband-Funksignalen unterstützt.

5. Mehrbandantenne (20) nach Anspruch 1, dadurch gekennzeichnet, dass der erste Abstrahlbereich (L) und der zweite Abstrahlbereich (H) aus gebogenen Leitern geformt sind, die einen einheitlichen Querschnitt aufweisen.

6. Mehrbandantenne (20) nach Anspruch 1, dadurch gekennzeichnet, dass die Mehrbandantenne (20) ferner eine Halterung (24, 26) umfasst, die ein Trägermaterial zum Schützen einer Struktur der Mehrbandantenne (20) oder Anpassen von Charakteristiken der Mehrbandantenne (20) enthält.

7. Mehrbandantenne (20) nach Anspruch 6, dadurch gekennzeichnet, dass die Halterung (24, 26) erlaubt, dass die Antenne (20) in eine Leiterplatte (22, 28) eingebettet wird, so dass verschiedene Abschnitte der Mehrbandantenne (20) auf beiden Seiten der Leiterplatte (22, 28) verteilt sind.

Revendications

1. Antenne multibande (20) comprenant :

une partie de couplage (CP) pour introduire ou générer en sortie des signaux ;

une première partie de rayonnement (L) couplée à une extrémité de la partie de couplage (CP) ; la première partie de rayonnement (L) étant courbée au niveau d'un ou plusieurs points de flexion (L1p, L2p, L3p, L4p) en vue de former une pluralité de sections (L1, L2, L3, L4, L5), dans laquelle une section terminale (L5) est une section de la première partie de rayonnement (L) la plus éloignée de la partie de couplage (CP) ; et

une seconde partie de rayonnement (H) couplée à une autre extrémité de la partie de couplage (CP) ; la seconde partie de rayonnement (H) comprenant au moins deux sections (H1, H2), dans laquelle la section terminale (H2) de la seconde partie de rayonnement (H) est parallèle à la section terminale (L5) de la première partie de rayonnement (L), afin d'obtenir des caractéristiques de rayonnement des deux sections parallèles couplées entre elles en vue d'augmenter une largeur de bande de l'antenne multibande (20) ;

caractérisée en ce que

la première partie de rayonnement est courbée en vue de former une première section principale (L1), une seconde section principale (L3) et la section terminale (L5) ; la première section principale (L1) et la seconde section principale (L3) définissant un premier plan (P1), la seconde section principale (L3) et la section terminale (L5) définissant un second plan (P2), le premier plan (PI) et le second plan (P2) n'étant pas parallèles l'un et l'autre ; et la distance (d) entre la section terminale (H2) de la seconde partie de rayonnement (H) et la section terminale (L5) de la première partie de rayonnement (L) étant inférieure à une distance entre la section terminale (H2) de la seconde partie de rayonnement (H) et une quelconque autre section de la première partie de rayonnement (L).

2. Antenne multibande (20) selon la revendication 1, caractérisée en ce que la seconde partie de rayonnement (H) est courbée au niveau d'un ou plusieurs points de flexion (H1p) en vue de former une pluralité de sections.

3. Antenne multibande (20) selon la revendication 1, caractérisée en ce que certaines des sections de la seconde partie de rayonnement (H) sont sur un même plan que la section terminale (L5) de la première partie de rayonnement (L).

4. Antenne multibande (20) selon la revendication 1, caractérisée en ce que la première partie de rayonnement (L) est utilisée pour rayonner des ondes électromagnétiques dans des bandes de basse fréquence, la seconde partie de rayonnement (H) est utilisée pour rayonner des ondes électromagnétiques dans des bandes de haute fréquence, de sorte que l'antenne multibande (20) prend en charge la transmission et la réception de signaux sans fil multibandes.

5. Antenne multibande (20) selon la revendication 1, caractérisée en ce que la première partie de rayonnement (L) et la seconde partie de rayonnement (H) sont formées au moyen de conducteurs courbés présentant des sections transversales uniformes.

6. Antenne multibande (20) selon la revendication 1, caractérisée en ce que l'antenne multibande (20) comprend en outre un dispositif de support (24, 26) lequel comprend un matériau support pour protéger une structure de l'antenne multibande (20) ou pour ajuster des caractéristiques de l'antenne multibande (20).

7. Antenne multibande (20) selon la revendication 6, caractérisée en ce que le dispositif de support (24, 26) permet à l'antenne d'être intégrée dans une carte de circuit (22, 28) de sorte que différentes sections de l'antenne multibande (20) sont réparties des deux côtés de la carte de circuit (20, 28).

Drawing