An antenna arrangement

The invention relates to an antenna arrangement, in particular to an antenna system for a mobile mobile phone.

Background of the Invention [0002] In recent years, it has become desirable that radio communication devices be ever smaller and easier to be carried by users. However, the bandwidth of the antenna system in such a device usually depends on the size of the device. In general, the band of the antenna system decreases when the size of the device decreases. For example, the antenna system bandwidth decreases if the dimensions of the base plate (usually the circuit board of the device being printed) decreases, or if the height of the antenna system over the base plate decreases. Currently, the antenna systems are equipped with a tunable load that can shift the narrow bandwidth of each antenna to the correct operating frequency. For example, tunable loads can shift the operating frequency from GSM 1800 to GSM 1900.

[0003] Document (US7148846) relates to a multi-component antenna for a wireless communication device. The antenna includes a first antenna element having a first operational frequency band and a free antenna element positioned adjacent the first antenna element for electromagnetic coupling with the first antenna element. The free antenna element is configured to work in conjunction with the first antenna element in the range of the second operating frequency band. The power port connected to the first antenna element connects the first antenna element to the communication system and changes the communication signals between the multi-element antenna and the communication system in both the first operating frequency band and the second operating frequency band.

[0004] Document (US6476769) relates to a radio antenna including a first microchip having a first resonant frequency (GSM1800), a second micropip connected to a first common element for sharing a first power point, and a third microprobe having a separate second power point. The first switch and the second switch are used to connect the first and second power point respectively to the point of the earth potential system. In order to cause the second and third micropedets to produce, respectively, a second resonant frequency (E-GSM900) and a third resonant frequency (PCS1900), the first switch is set in the open position and the second in the closed position. In order to cause the first and third micropiles to produce the third and fourth resonance frequency (UMTS) respectively,

[0005] However, it may be desirable to provide an alternative antenna arrangement.

Brief description of the invention [0006] According to one embodiment of the invention an antenna system is provided comprising: a first antenna element connected to a first power point and having a first electrical length; a second antenna element connected to a second power point different from the first power point and comprising: a first strip that extends from the second power point and has a second electrical length similar to the first electrical length that allows the first stripe to electromagnetically engage the first antenna element; and a second strip that extends from the second power point and has a third electrical length different from the first electrical length of the first antenna element and from the second electrical length of the first strip.

[0007] At least a portion of the first strip of the second antenna element may extend from the second power point towards the first antenna element. At least a portion of the first strip of the second antenna element may be oriented such that it is substantially parallel to the first antenna element.

[0008] The first antenna element can be physically connected to only the first power point. The first antenna element can be a flat inverted antenna L. The first antenna element can have a resonance at λ / 4.

[0009] The second antenna element may be physically connected to only the second power point. The second antenna element may be a flat inverted antenna L. The second antenna element may have a resonance at λ / 4.

[0010] The first antenna element may be connected to the first transceiver device via the first power point. The second antenna element can be connected to a second transceiver device via a second power point. The first transceiver may be different from the second transceiver device.

[0011] The first antenna element and the second antenna element may be connected to a single transceiver device via a first power point and a second power point.

[0012] The first antenna element can operate at a resonant frequency from the first resonant frequency band. The first strip of the second antenna element can work with the resonant frequency from the second resonant frequency band. The first resonant frequency band and the second resonant frequency band may have at least partially coincident frequencies. The second strip of the second antenna element may operate at a resonant frequency from the third resonant frequency band. The third resonant frequency band may be different from the first resonant frequency band and from the second resonant frequency band.

[0014] According to another embodiment of the invention, there is provided a device comprising an antenna arrangement as described in the previous paragraph.

[0015] According to a further embodiment of the invention, there is provided a portable electronic device comprising an antenna arrangement as described in the preceding paragraph.

[0016] According to another embodiment of the invention, there is provided a mobile mobile telephone comprising an antenna arrangement as described in the previous paragraph.

Brief Description of the Drawing [0017] For a better understanding of the invention, reference will now be made, by way of example only, to the description of an embodiment of the invention with reference to the accompanying drawings in which:

Fig 1 is a schematic diagram of a device comprising an antenna arrangement according to a first embodiment of the invention;

Fig. 2 is a schematic diagram of a device comprising an antenna arrangement according to a second embodiment of the invention;

Fig. 3 shows a top view of the antenna according to one embodiment of the invention;

Fig. 4 is a perspective view of the antenna arrangement shown in Fig. 3;

Fig. 5A shows a top view of the antenna arrangement shown in Fig. 3 and Fig. 4 with only the first antenna element being fed;

Fig. 5B is a top view of the antenna arrangement shown in Fig. 3 and Fig. 4 with only the second element of the antenna powered;

Fig. 5C illustrates a top view of the antenna arrangement shown in Fig. 3 and Fig. 4 with the first and second antenna element supplied with power;

Fig. 6 shows a graph of performance versus frequency for an antenna arrangement according to one embodiment;

Fig. 7 is a plan view of an antenna arrangement according to another embodiment of the invention;

Fig. 8 shows a top view of an antenna arrangement according to another embodiment of the invention;

Fig. 9 is a plan view of an antenna arrangement according to another embodiment of the invention;

Detailed description of embodiments of the invention [0018] Figs. 3, 4, 5A, 5B, 5C, 7, 8 and 9 show an antenna system 12 comprising: a first antenna element 34 connected to a first power point 20 and having a first electrical length; a second antenna element 36 connected to a second power point 22, different from the first power point 20 and comprising: a first strap 40 extending from the second power point 22 and having a second electrical length similar to the first electrical length that allows the first electromagnetic belt 40; coupling with the first antenna element 34 and a second band 42 which extends from the second point

The power supply 22 has a third electrical length, different from the first electrical length of the first antenna element 34 and from the second electrical length of the first strap 40.

[0019] Fig. 1 shows a device 10 such as a portable electronic device (e.g., a mobile cellular telephone), a cellular base station, another radio communication device or a module of such a device according to a first embodiment of the invention.

[0020] The device 10 includes an antenna arrangement 12, an adapting circuit 14, a transceiver 16 and a functional circuit 18. The antenna system 12 comprises a first power point 20 and a second power point 22. The matching circuit 14 is connected to the first power point 20, second the power point 22 and the transceiver 16. In one embodiment, the matching circuit 14 is a duplexer and matches the antenna arrangement to a single point with a 50 ohm impedance. The functional circuit 18 is connected to the transceiver 16 and is active providing signals to the transceiver 16 and receiving signals from the transceiver 16.

[0021] In an embodiment in which the device 10 is a mobile cellular telephone, the functional circuit 18 includes a processor, memory and input / output devices such as a microphone, a loudspeaker and a display. The electronic components forming the matching circuit 14, the transceiver 16 and the functional circuit 18 are connected to each other by a printed circuit board (PWB). The circuit board can be used as a base plate for the antenna system 12.

[0022] Fig. 2 shows a device 10 such as a portable electronic device (e.g., a mobile cellular telephone), a cellular base station, another radio communication device or a module of such a device according to a second embodiment of the invention.

[0023] The apparatus 10 includes an antenna arrangement 12, a first matching circuit 24, a second matching circuit 26, a first transceiver device 28, a second transceiver device 30 and a functional circuit 18. The antenna system 12 includes a first power point 20 and a second power point 22. A first matching circuit 24 is connected to the first power point 20 of the antenna arrangement 12 and to the first transceiver device 28. The second matching circuit 26 is connected to the second power point 22 of the antenna arrangement 12 and to the second transceiver 30. In one embodiment , the first and second tuning circuits 24, 26 match first and second power points 20, 22 to points with 50 ohm impedance.The functional circuit 18 is connected to the first transceiver 28 and the second transceiver 30 and works, providing signals to the transceiver and receiving signals from the transceiver.

In an embodiment in which the device 10 is a mobile cell phone, the functional circuit 18 includes a processor, memory and input / output devices such as a microphone, a loudspeaker and a display. Electronic components forming the first

- a matching circuit 24, a second matching circuit 26, a first transceiver device 28, a second transceiver device 30 and a functional circuit 18 are connected to one another by a printed circuit board (PWB). The circuit board can be used as a base plate for the antenna system 12.

[0025] The embodiment shown in Fig. 2 may be a more advantageous solution compared to the example shown in Fig. 1, since the transceivers28, 30 may require less switch contacts than the transceiver 16. As a result, transceivers 28, 30 may have less losses than the transceiver 16. In addition, transceivers 28, 30 may be less complex than the transceiver 16, and therefore may be cheaper. In addition, the matching systems 24, 26 can be less complex than the matching circuit 14, because they are optimized for a smaller frequency band. As a result, the matching systems 24, 26 can be cheaper and easier to perform than the matching system 14.

[0026] Fig. 3 shows a top view of one embodiment of the antenna system 12 as one embodiment of the invention. The coordinate system 32 is shown in Figs. 3 and 4. The coordinate system 32 is a Cartesian coordinate system and contains an x-axis perpendicular to the y-axis and z-axis (see Fig. 4) perpendicular to both the x-axis and the y-axis.

The antenna arrangement 12 includes a first antenna element 34 connected to the first power point 20 and a second antenna element 36 connected to the second power point 22. The first antenna element 34 and the second antenna element 36 are mounted on a printed circuit board (PWB) 38 that operates as a base plate for the antenna layout. As shown in FIG. 4, the first antenna element 34 and the second antenna element 36 are mounted above the base plate 38 in the z-axis direction at a height h.

In this embodiment, the first antenna element 34 and the second antenna element 36 are planar inverted L antennas and are physically connected (e.g., via a galvanic connection) only to the first power point 20 or respectively only to the second power point 22. Structure and the functions of the first and second antenna element 34, 36 are explained in more detail in the following paragraphs.

[0029] The first antenna element 34 extends from the power point 20 in the + y direction to its end point (a). The second antenna element 36 includes a first bar 40 and a second bar 42. The first bar 40 extends from the second power point 22 towards the first antenna element 34 in the + x direction to its end (b). The second strip 42 extends from the second power point 22 in the direction - x to the point (c) in which the strip turns right at a right angle. From point (c), the second bar extends in the + y direction to its end (d).

[0030] The first antenna element 34 has a length L1 and has at least one active resonance mode at L1 = λ / 4 (assuming that the physical length and electrical length are the same). The first strip 40 of the second antenna element 36 has a length L2 and has at least one active resonant mode at L2 = λ / 4. The second strip 42 of the second antenna element 36 has a length L3 and at least one active resonant mode at L3 = λ / 4.

[0031] It should be noted that the electrical length of the antenna is usually equal to the length of the resonant portion of the antenna plus the shortening / extension effect introduced by the reactive components in the associated matching circuit. For example, the electrical length of the antenna will be increased if the antenna is connected to multiple coils connected in series. Similarly, the electrical length of the antenna will be reduced if the antenna is connected to the capacitors. Thus, the electrical length of the first antenna element 34, the first strip 40i of the second strip 42 of the second antenna element 36 can be selected by varying the reactive components in the matching systems 14, 24, 26.

[0032] The length L1 of the first antenna element 34 is selected such that this element is active in transmitting and receiving signals in the first resonant frequency band. Similarly, the lengths of the first strip 40 and the second strip 42, L2 & L3, respectively, are selected so that these stripes are active in transmitting and receiving signals in the second and third resonant frequency bands respectively. It should be noted that the electrical lengths of the first L1 antenna element and the first L2 strip are similar (and in some embodiments may be substantially the same) because they are selected to operate in a resonant state in similar resonant frequency bands. Means, that the frequencies of the first resonant frequency band overlap at least partially with the frequencies of the second resonant frequency band (i.e., the two frequency bands share a common set of frequencies). The third resonant frequency band is different from the first and second resonant frequency bands and these bands have no common frequencies.

[0033] In operation, the antenna system 12 can be electrically powered via the first power supply point 20 and / or via the second power point 22.

[0034] As shown in Fig. 5A, if the antenna system 12 is powered only via the first power point 20 (indicated by arrow 44) and not via the second power point 22, then only the first antenna element 34 is directly electrically powered. As a result, the first antenna element 34 generates a signal from the first resonant frequency band. However, since L2 is similar to L1 as stated above and because the first bar 40 is directed towards the first antenna element 34, the first antenna element 34 is electromagnetically coupled to the (unpowered) first band 40. As a result of this electromagnetic coupling, the first bar 40 is electromagnetically powered through the first antenna element 34 and produces a signal from the second resonant frequency band, i.e.

[0035] As shown in Fig. 5B, if the antenna system 12 is powered only via the second power point 22 (indicated by the arrow 46) and not via the first power point 20, then only the second antenna element 36 is directly electrically powered. As a result, the first strip 40 generates a signal from the second resonant frequency band and the second band 42 generates a signal from the third resonant frequency band. The first strip 40 is electromagnetically coupled to the (unpowered) first element 34 of the antenna. IN

As a result of this electromagnetic coupling, the first antenna element 34 is electromagnetically fed through the first band 40 and produces a signal from the first resonant frequency band, i.e. the first antenna element 34 acts as a passive resonator for the first band 40.

[0036] As shown in Fig. 5C, if the antenna system 12 is powered via the first power point 20i via the second power point 22 (designated by arrows 48 and 50 respectively), then the first antenna element 24, the first belt 40 and the second belt 42 produce signals from their respective resonant frequency bands.

[0037] The functional circuit 18 shown in Fig. 1 is operable to control the transceiver 16 to switch between the configurations shown in Figs. 5A, 5B and 5C. Specifically, the functional circuit 18 can control the transceiver 16 to provide an output to the first power point 20 and / or a second power point 22. In this way, the functional circuit 18 can select for operation the first antenna element 34 and / or the second antenna element 36.

[0038] The functional circuit 18 shown in Fig. 2 is operable to control the first transceiver device 28 and the second transceiver device 30 to switch between the configurations shown in Figs. 5A, 5B and 5C. A particularly functional circuit 18 may control the first transceiver device 28 and the second transceiver device 30 so that the output is provided to the first power point 20 and / or the second power point 22. As mentioned in the previous paragraph, this way it is functional. the circuit 18 can select for operation the first antenna element 34 and / or the second antenna element 36.

[0039] In one embodiment, the antenna arrangement 12 has the frequency response shown in Fig. 6. Fig. 6 is a capacity graph (plotted on the y-axis 52) as a function of the frequency (plotted on the x-axis 54 perpendicular to the y-axis).

[0040] The frequency response of the first antenna element 34 is shown by a line 56, which rises to the flat portion 57 at about 1.7 GHz and then drops from a flat portion 57 at about 2.2 GHz. The flat section 57 corresponds to the first resonant frequency band of the first antenna element 34.

[0041] Line 58 shows the frequency response of the second antenna element 36, which increases to a first maximum of 60 at 0.9 GHz, drops to a minimum at 1.8 MHz and then increases to a second maximum of 62 at 2.3 GHz. The first maximum 60 corresponds to the third resonant frequency band of the second band 42, and the second maximum 62 corresponds to the second resonant frequency band of the first band 40. In FIG. 6, it can be seen that the first and second resonant frequency bands (i.e., connecting the flat segment 57 to the second maximum) 62) expands the antenna system bandwidth 12 to around 2 GHz.

[0042] As can be seen from the above paragraphs, the first antenna element 34 and the first strip 40 are able to function as passive antennas when the second one is directly electrically powered. This property is advantageous because the first element

The antennas and the first bar 40 are capable of operating in similar resonance frequency bands, so the antenna system band 12 is effectively expanded at these frequencies.

[0043] In addition, external objects (such as a user's finger) may have a smaller impact on the operation of the antenna system 12 than in the case where the antenna system includes a passive antenna attached only to the ground. In the antenna system, which contains a passive antenna connected only to the ground, the operation of a passive antenna is strongly dependent on the electromagnetic passive coupling of the antenna with the active antenna. If the user places his finger over such an antenna arrangement, the electromagnetic coupling between these antennas may decrease and consequently degrade the performance of the passive antenna. In the embodiment of the invention, the first antenna element 34 and the second antenna element 36 can be powered independently of one another and their operation is not solely dependent on the electromagnetic coupling.

[0044] In one embodiment, the physical lengths of the first antenna element 34, the first strip 40 and the second strip 42 are 18 mm, 12 mm and 48 mm, respectively. It can be seen that the physical length of the first antenna element 34 differs from the physical length of the first bar 40. Other electric lengths are similar, because both of these elements are attached to the matching system (s) 14, 24, 26, containing reactive components selected to provide these elements with similar electrical lengths. The gap (G) between the first antenna element 34 and the first strip 40 is 11 mm. In this embodiment, the first antenna element 34 has a resonant frequency band with a center at 1.7 GHz, the first band 40 has a resonant frequency band with a center at 2.1 GHz, and the second band 42 has a resonant frequency band with the center at 900 MHz. As mentioned above, it can be seen that since the first antenna element 34 and the first bar 40 operate in a similar resonance frequency band, they therefore increase the antenna system bandwidth 12 to relatively high frequencies (around 2 GHz).

[0045] Fig. 7 is a top view of an antenna arrangement according to another embodiment of the invention. The embodiment shown in Fig. 7 is similar to the embodiment shown in Fig. 3, and because the functions are similar, the same numbers used to denote the individual elements of the drawing were used.

[0046] The embodiment shown in Fig. 7 differs from that shown in Fig. 3 in that the first strip 40 of the second antenna element 36 extends from the power point 22 in the + x direction to the point (e) in which it turns left under right angle and then runs in the + y direction (parallel to the first antenna element 34) to its end point (f). This embodiment can provide the advantage that it can increase the electromagnetic coupling between the first strip 40 and the first antenna element 34 because the end point (f) of the first strip 40 lies closer to the end point (a) of the first antenna element 34, where the electric field is maximum.

[0047] Fig. 8 is a top view of an antenna arrangement according to another embodiment of the invention. The embodiment shown in Fig. 8 is similar to the embodiment shown in Fig. 7,

-9a because the functions are similar, the same numbers used for the individual elements of the drawing were used.

[0048] The embodiment shown in Fig. 8 differs from that shown in Fig. 7 in that the second strip 42 of the second antenna element 36 extends from the point (c) in the + y to the point (g), where it turns right at an angle simple. Then, the second bar 42 runs from point (g) in the + x direction to its end point (h). This embodiment can provide the advantage that it can reduce the volume needed for the antenna system 12 because the second band 42 is bent (at points (c) and (g)), which reduces the length of the second strip 42 in the + y direction.

[0049] Fig. 9 illustrates a top view of an antenna arrangement according to another embodiment of the invention. The embodiment shown in Fig. 9 is similar to the embodiment shown in Fig. 3 and Fig. 7, and because the functions are similar, the same numbers used to denote the individual elements of the drawing were used.

[0050] The embodiment shown in Fig. 9 differs from that shown in Figures 3 and 7 in that the first strip 40 of the second antenna element 36 extends from the power point 22 only in the + y direction to its end point (I). In this embodiment, the course of the first strip is substantially parallel to the first antenna element 34 along the entire length L2.

[0051] Because the electrical length of the first element 34, the first strip 40 and the second strip 42 can be selected to obtain different resonance frequency bands, it can be seen that the embodiments of the invention are not limited to the resonant frequency bands mentioned above. For example, their lengths can be chosen so that they will work in a resonance state in any of the following resonant frequency bands and utilizing different protocols. For example, different frequency bands and protocols may include US-GSM 850 (824-894 MHz); EGSM 900 (880960 MHz); PCN / DCS1800 (1710-1880 MHz); US-WCDMA band (1850-1990); WCDMA21000 band (Tx: 1920-19801, Rx: 2110-2180) and PCS1900 (1850-1990 MHz).

[0052] Additionally, it can be seen that the embodiments of the invention are not limited to protocols used in cellular telephony. Embodiments of the invention may operate using only protocols used in cellular telephony, protocols used in cellular telephony and other protocols or only protocols other than those used in cellular telephony. For example, non-cellular protocols may include 2.5 GHz WLAN / BT, 5 GHz WLAN and UWB 3-6 GHz.

[0053] Although various embodiments of the invention have been described in the preceding paragraphs, it should be noted that modifications to the exemplified embodiments are possible without departing from the scope of the invention as set out in the claims. For example, the first antenna element 34 may be a planar inverted antenna F (PIFA) and / or the second antenna element 36 may be a PIFA.

[0054] The PILA antenna is more advantageous in the embodiments of the invention than PIFA, since PIFA acts as a passive element, so its electrical length is not tuned by attaching the matching circuit. Because by attaching reactive

-10 elements in the matching circuit can not increase the electrical length of PIFA, when it acts as a passive antenna, the physical length of PIFA can be greater than the physical length of the PILA at a given operating frequency. Thus, from the fact that the first and second antenna element 34, 36 is a planar inverted antenna L, there is the advantage that the required volume of the antenna system 12 can be reduced.

[0055] Aiming in the foregoing description to pay attention to those functions of the invention that are particularly important, it should be understood that the Applicant claims all patent-protected features or combinations of features mentioned above and / or shown in the drawing, independently of this whether special emphasis was placed on them.