EP2916386A1

EP2916386A1 - Antenna and method of operating an antenna

Info

Publication number: EP2916386A1
Application number: EP14290057.0A
Authority: EP
Inventors: Dirk Wiegner; Wolfgang Dr. Templ; Andreas Dr. Pascht
Original assignee: Alcatel Lucent SAS
Current assignee: Alcatel Lucent SAS
Priority date: 2014-03-07
Filing date: 2014-03-07
Publication date: 2015-09-09

Abstract

The invention relates to an antenna (100) comprising at least one antenna element (110) for transmitting and/or receiving radio frequency, RF, signals, wherein said antenna (100) comprises at least one electromechanic actuator (120) for moving said at least one antenna element (110) with respect to a further component of said antenna (100).

Description

Field of the invention

The invention relates to an antenna comprising at least one antenna element for transmitting and/or receiving radio frequency, RF, signals. The invention further relates to a method of operating an antenna.

Background

Conventional antennas with a configurable antenna characteristic, i.e. beam pattern, usually require electronic phase shifting means which provide phase-shifted copies of e.g. a transmission signal to different antenna elements in order to control the antenna characteristic for transmission of said transmission signal. The degree of variation of the beam pattern and the energy efficiency are limited by the available phase shifting devices due to a limited maximum achievable phase shift of the devices and insertion/transmission losses. Also, since the phase shifting devices and their signal paths constitute further RF signal paths as opposed to a single RF transmission signal, the further known problems related thereto (undesired different electrical lengths / length variations due to external influences such as e.g. temperature, RF leakage / interference) increase proportionally with the required number of phase shifters.

Summary

In view of this, it is an object of the present invention to provide an improved antenna and an improved method of operating an antenna which avoid the disadvantages of the prior art.
Regarding the antenna of the above-mentioned type this object is achieved by said antenna comprising at least one electromechanic actuator for moving said at least one antenna element with respect to a further component of said Antenna. Electromechanic actuators enable to avoid electronic phase shifters and the associated disadvantages while requiring a comparatively low amount of electric control power.
According to an embodiment, said at least one antenna element is rotatably attached to a carrier element of said antenna, and said at least one electromechanic actuator is configured to drive a rotational movement of said at least one antenna element, whereby a particularly high flexibility regarding control of a beam pattern of the antenna is attained. If an antenna according to the embodiments comprises a single antenna element, its beam pattern may correspondingly be rotated by effecting said rotational movement of said at least one antenna element. If an antenna according to the embodiments comprises several antenna elements, wherein at least one of which is rotatable, the resulting beam pattern effected by all antenna elements may be influenced by rotating at least one antenna element.
According to a further embodiment, a plurality of antenna elements is attached on a common element carrier, wherein said common element carrier is rotatably attached to a carrier element of said antenna, and said at least one electromechanic actuator is configured to drive a rotational movement of said common element carrier. Thus, a plurality of antenna elements and their resulting beam pattern may be moved or rotated simultaneously.
According to a further embodiment, said at least one antenna element and/or said common element carrier is rotatably attached to a carrier element of said antenna such that said at least one antenna element and/or said common element carrier can be rotated around at least two different axes, whereby beam pattern control is even further enhanced.
According to a further embodiment, said at least one electromechanic actuator comprises an electroactive Polymer material (EAP). For example, EAP materials can advantageously change their dimensions ("grow" or "shrink") when stimulated by an electric voltage, e.g. a DC (direct current) voltage, or an AC voltage. Further advantageously, the amount of electrical energy required for a corresponding control mechanism is very small.
Examples for EAP material according to some embodiments are: Ionic Polymer Metal Composites (IPMCs), Polyacrylamide and Polayacrylic acid cross-linked gels, Carbon Nanotube based EAPs, VHB (a network of polymers; provided commercially as a tape from 3M Company), VHB Trimethylolpropane trimethacrylate interpenetration networks (TMPPMA).
According to a further embodiment, alternatively or additionally to EAP materials, piezoelectric actuators may also be used.
According to a further embodiment, two electromechanic actuators are provided to drive said at least one antenna element. Of course, if according to an embodiment a rotatable common element carrier is provided, it is also possible to provide two electromechanic actuators to drive said rotation of said rotatable common element carrier.
According to a further embodiment, a mounting pole is provided on said carrier element of said antenna, and said at least one antenna element is attached to said mounting pole. The mounting pole displaces the antenna element from said carrier element to enable movement of said antenna element without collision with the carrier element. According to an embodiment, the mounting pole may e.g. comprise a hinge for rotatably attaching said antenna element, or a ball-and-socket joint which enables further degrees of freedom regarding relative movement between the antenna element and the carrier element.
According to a further embodiment, said mounting pole comprises at least one radio frequency (RF) waveguide for contacting said antenna element, whereby RF signal transmission to/from said antenna element is ensured.
According to a further embodiment, at least one antenna element comprises a flexible waveguide connected to said antenna element. If a mounting pole is provided, the flexible waveguide may be attached to or integrated into said mounting pole. In configurations without mounting pole, the flexible waveguide may e.g. be arranged between the antenna element, its driving electromechanic actuator(s) and a carrier element.
According to a further embodiment, said at least one electromechanic actuator comprises a basically cylindrical geometry, particularly with a rectangular cross-section.
According to a further embodiment, at least two electromechanic actuators are provided which comprise different geometry and/or size. I.e., according to an embodiment, at least two electromechanic actuators may e.g. comprise different geometry and/or size in a non-operational state. According to a further embodiment, at least two electromechanic actuators may comprise a same geometry and/or size in the non-operational state, and by applying different control voltages they may be influenced to attain different size and/or geometry during operation.
A further solution to the object of the present invention is provided by a method of operating an antenna comprising at least one antenna element for transmitting and/or receiving radio frequency, RF, signals, wherein said antenna comprises at least one electromechanic actuator, and wherein said at least one antenna element is moved with respect to a further component of said antenna by means of said at least one electromechanic actuator.
According to an embodiment, said step of moving comprises a step of rotating.
According to a further embodiment, a predetermined control voltage is applied to said at least one electromechanic actuator, preferably by means of electrodes attached to said at least one electromechanic actuator.

Brief description of the figures

Further features, aspects and advantages of the present invention are given in the following detailed description with reference to the drawings in which:

Figure 1a: schematically depicts a side view of an antenna according to an embodiment in a first operational state,
Figure 1b: schematically depicts the antenna according to Figure 1a in a second operational state,
Figure 2: schematically depict a side view of an antenna according to a further embodiment,
Figure 3a, 3b, 3c: schematically depict perspective views of an antenna according to an embodiment in different operational states,
Figure 4, 5, 6: schematically depict perspective views of antennas according to further embodiments,
Figure 7: schematically depicts a flow-chart of a method according to an embodiment, and
Figure 8: schematically depicts an electromechanic actuator according to an embodiment.

Description of the embodiments

Figure 1a schematically depicts a side view of an antenna 100 according to a first embodiment. The antenna 100 comprises a carrier element 102. A first antenna element 110 is provided which is used for transmitting and/or receiving radio frequency signals in a per se known manner. According to the present embodiment, an electromechanic actuator 120 is provided such that a first surface 120a of said electromechanic actuator 120 is arranged on a surface 102a of said carrier element 102. The antenna element 110 is arranged on a mounting element 130 to which it is movably, according to the present embodiment rotatably around axis A1, attached, said mounting element 130 also being arranged on the carrier element 102. Note that the various elements are not necessarily drawn to scale for reasons of clarity.
The electromechanic actuator 120 is arranged on said carrier element 102 so that a second surface 120b of the electromechanic actuator 120 is close to/contacts an end section of the antenna element 110 as depicted by Figure 1a.
Advantageously, the electromechanic actuator 120 can alter its geometry, presently for example its height H as indicated by the double arrow H of figure 1a. Thus, a rotational movement of said antenna element 110 around the axis A1 may be effected, as long as the point of contact between the actuator 120 and the antenna element 110 does not coincide with the axis A1. Although according to the present embodiment, the surface 120b of the actuator 120 is arranged close to a horizontal end section of antenna element 110, it is evident that according to other embodiments the actuator 120 may be positioned more closely to the mounting element 130, whereby same length changes of the actuator 120 will translate into increased rotational movements of the antenna element 110.
According to one embodiment, the height H of the electromechanic actuator 120 may be altered (e.g., increased or decreased) by applying a corresponding control voltage to the electromechanic actuator 120. For example, electrically conductive electrodes (not shown) may be applied to the surfaces 120a, 120b of the electromechanic actuator 120 to apply a control voltage. Optionally, isolating layers may be provided between said electrodes and e.g. the carrier element 102 or a component of the electromechanic actuator 120 which comes into contact with the antenna element 110 to provide for galvanic isolation therebetween.
By altering the geometry of the electromechanic actuator 120 and thus moving the antenna element 110 with respect to the carrier element 102, which presently corresponds to rotating said antenna element 110 around the axis A1, a beam pattern of the antenna 100 may correspondingly be influenced, i.e. rotated.
I.e., if an antenna according to the embodiments comprises a single antenna element 110, as depicted by Figure 1a, its beam pattern may correspondingly be rotated by effecting said rotational movement of said at least one antenna element 110. However, if an antenna according to the embodiments comprises several antenna elements, wherein at least one of which is rotatable, the resulting beam pattern effected by all antenna elements may be influenced by rotating least one antenna element, because a phase relationship of RF signals transmitted by the rotated antenna element 110 with respect to other RF signals emitted e.g. by further antenna elements of the antenna which may e.g. directly attached to the surface 102a of the carrier element 102, may be altered.
Figure 1b schematically depicts a side view of the antenna 100 according to figure 1a in a second operational state. As can be seen from figure 1b, the electromechanic actuator 120 comprises an increased height H2 with respect to the first operational state depicted by figure 1a. Thus, a non-vanishing angle of rotation α is effected between a reference plane of the antenna element 110 and a further reference plane constituted by the surface 102a of the carrier element 102 of the antenna 100.
Figure 2 schematically depicts a side view of an antenna 100a according to a further embodiment. In contrast to the embodiment explained above with reference to figure 1a, 1b, the antenna 100a according to figure 2 comprises a common element carrier 1100 which is rotatably mounted on top of said mounting element 130 instead of a single antenna element 110 as depicted by figure 1a. Rather, the common element carrier 1100 comprises a plurality of presently three antenna elements 110_1, 110_2, 110_3 which are arranged on a surface of the common element carrier 1100. Thus, when effecting height changes of the electromechanic actuator 120, all individual antenna elements 110_1, 110_2, 110_3 experience the same angle of rotational movement of their common carrier element 1100, whereby a beam pattern of the antenna 100a is rotated in accordance with the height change of the electromechanic actuator 120.
Figure 3a schematically depicts a perspective view of an antenna 100b according to a further embodiment. In contrast to the embodiments explained above with reference to figures 1a, 1b, 2, the antenna 100b comprises two electromechanic actuators 1200a, 1200b for driving a single antenna element 110. As can be seen from figure 3a, mounting elements 1300, 1302 extend basically perpendicular from the surface 102a of the carrier element 102 of the antenna 100b. A hinge mechanism or any other suitable mounting is provided at the upper end sections of the mounting components 1300, 1302 which enables a rotational movement of the antenna element 110 being attached to said hinge/mounting mechanism around an axis A1. In contrast to the embodiments according to figure 1a to figure 2, rotational movement of the antenna element 110 of antenna 100b according to figure 3a can be effected by simultaneously controlling both electromechanic actuators 1200a, 1200b in an inverse fashion such that inverse height changes of the actuators 1200a, 1200b are effected contributing to a single uniform drive force for rotating the antenna element 110 around axis A1. Control electrodes for applying an electric control voltage to the actuators 1200a, 1200b may e.g. be provided on front surfaces of the actuators 1200a, 1200b, c.f. e.g. the front surfaces 120a, 120b of actuator 120 according to figure 1a.
Also depicted in figure 3a is a transceiver unit 200, which may be provided for providing radio frequency (RF) signals that are forwarded to the antenna element 110 for transmission via RF signal line 202. The transceiver unit 200 may also be configured for receiving RF signals received by the antenna element 110 and forwarded to the transceiver unit via RF signal line 202. It is to be noted that said transceiver unit 200 is depicted for exemplary purposes only and the said transceiver unit 200 is not essential to the principle of the embodiments.
Preferably, a connecting point of the RF signal line 202 and the antenna element 100 is comparatively close to the axis of rotation A1 of the antenna element 110 to avoid undesired mechanical strain on said RF signal line 202.
According to an embodiment, in addition to processing RF signals to/from the antenna element 110, the transceiver unit 200 may also comprise control functionality to provide an electric direct current (DC) voltage and/or alternate current (AC) voltages for controlling the length/height changes of the electromechanic actuator 1200a, 1200b.
According to a further embodiment, the control functionality for controlling the electromechanic actuators 1200a, 1200b may also be provided in form of an extra control unit (not shown).
Figure 3b schematically depicts a perspective view of the antenna 100b according to figure 3a in a further operational state, wherein the second electromechanic actuator 1200b (figure 3a) comprises a reduced height with respect to the operational state of figure 3a, and wherein the first electromechanic actuator 1200a comprises an increased height with respect to the operational state as depicted by figure 3a. The inverse operational scenario is illustrated by figure 3c.
To effect transitions between the three different operational states depicted by fig. 3a to 3c, three respective sets of control voltages may be applied to the electromechanic actuators 1200a, 1200b of the antenna 100b, for example by a respective control unit function block integrated to said transceiver 200 or by a dedicated control unit (not shown). Depending on the specific type of actuator, positive and/or negative DC (direct current) or AC (alternating current) voltages may be employed.
According to a further embodiment, in addition to the configuration of actuators 1200a, 1200b of Fig. 3a, at least one further actuator (not shown) may be provided to enable further degrees of freedom for moving the antenna element 110. For example, in Fig. 3a, a further electromechanic actuator may be arranged beneath carrier 102 such that the whole configuration 102, 1200a, 1200b, 110, 1300, 1302 may be displaced in a vertical direction, which - when providing said antenna 100b of Fig. 3a with several antenna elements 110 - enables to introduce a relative phase change between the antenna element comprising said further actuator and other antenna elements (not shown) of said antenna 100b.
Figure 4 schematically depicts a perspective view of an antenna 100c according to a further embodiment.
While the rotatable mounting of the antenna element 110 according to figure 4 is comparable to the embodiment according to figure 3a, a single electromechanic actuator 1200c is provided for driving the rotational movement of the antenna element 110 of the antenna 110c. Additionally, a spring force element 1220 is positioned with respect to the antenna 110 such that it exerts a spring force on the antenna element 110 and the carrier element 102, said spring force depending on an angular position of the antenna element 110 with respect to a reference plane e.g. defined by surface 102a. Thus, rotating the antenna element 110 in a clockwise fashion may be attained by correspondingly increasing the height of the electromechanic actuator 1200c, i.e. by applying a respective control voltage, and rotating the antenna element 110 in a counter-clockwise fashion may be attained by said spring force element 1220 exerting a corresponding resetting force regarding an angle of rotation of the antenna element 110. According to one embodiment, the spring force element 1220 may e.g. comprise a block of elastically deformable material.
Figure 5 schematically depicts a perspective view of an antenna 100d according to a further embodiment. In contrast to the configuration of figure 4, a spring force unit 1222 is arranged opposite to the electromechanic actuator 1200d with respect to the axis of rotation of the antenna element 110. Thus, similar to the embodiment according to figure 4, a spring force or generally restoring force may be applied to the antenna element 110 depending on an angular position of the antenna element 110. For instance, if the electromechanic actuator 1200d is controlled to increase its height, the spring force unit 1222 is compressed to some extent in vertical direction by the rotational movement of the antenna element 110, which enables a restoring force to be applied to the antenna element 110 and to rotate it back counter-clockwise once the height of the electromechanic actuator 1200d decreases, e.g. due to respective application of control voltage.
According to an embodiment, an initial vertical extension of the elastic material of the spring force unit 1222 is chosen in that way that an antenna is tilted over to the left (not shown in Figure 5, but similar as e.g. depicted by Fig. 3c). By this configuration, the rotational angle, or "tilt", of the antenna can be controlled by control voltage for the actuator 1200d. For rotating or tilting the antenna element 110 in Figure 5 to the right, the actuator 1200d has to provide sufficient pressure allowing to compress the elastic material of the spring force unit 1222.
Figure 6 schematically depicts a perspective view of an antenna 100e according to a further embodiment. Instead of a hinge mechanism as explained above, which enables one rotational degree of freedom, i.e. rotation around a first axis A1, the embodiment according to figure 6 comprises a mounting pole 140 which comprises a hinge mechanism or socket-and-ball connection or the like that enables the antenna element 110 to rotate around at least two axes A2, A3. Moreover, for driving the antenna element 110, according to the present embodiment, four electromechanic actuators are provided on the carrier element 102. For the sake of clarity only one electromechanic actuator 1200e is denoted with the reference sign in figure 6.
The configuration as depicted by figure 6 enables a particularly flexible mounting of the antenna element 110 on said mounting pole 140. Moreover, piston-shaped electro mechanic actuators can be used for driving said antenna element 110.
More specifically, by using four piston-shaped electro mechanic actuators, which are preferably arranged at corner positions of the antenna element 110, the antenna element 110 can flexibly be adjusted by suitable application of control voltage through their respective mechanic actuator (s).
According to an embodiment, it is proposed to use four independently controlled actuators, e.g. EA polymer (EAP) "pistons", one at each corner of the antenna element 110, whereby the antenna element 110 can be very flexibly be adjusted. In this embodiment, the four independently controlled actuators should be provided with suitable control signals (e.g., some of the EA polymer pistons extend, while others are contract, depending on the required adjustment; generally it is beneficial if the control voltage for one actuator is set depending on the control voltage(s) of further actuators driving the same antenna element). Advantageously, antenna feeding may e.g. be done by a feeding cable in the center (e.g. thru the post 140).
Instead of four actuators as shown by Fig. 6, any other number of actuators is also possible. For rotational movement of said antenna element 110 around at least two different axes A2, A3, preferably at least two actuators are provided. Three or more actuators are also possible according to further embodiments.
As already explained above with reference to the embodiments of figure 1a, 1b and figure 2, the principle according to the embodiments may be applied to configurations wherein a single antenna element 110 is to be moved, particularly rotated, as depicted by figure 1a, 1b. However, the same principle may also be applied to a configuration as exemplarily depicted by figure 2 wherein a common element carrier 1100 is moved or rotated, respectively, said common element carrier comprising more than one antenna element.
Figure 7 schematically depicts a flow-chart of a method according to an embodiment. In step 300, a desired beam pattern of the antenna 100 (Figure 1b) is set by applying a corresponding control voltage to the actuator 120, whereby the antenna element is rotated around axis A1 depending on the length change of actuator 120 in response to the application of said control voltage. After that, in step 310, the antenna transmits and/or receives RF signals using said desired beam pattern.
Figure 8 schematically depicts a side view of an electromechanic actuator 120 according to an embodiment. Presently, the electromechanic actuator 120 comprises an electroactive polymer material (EPA), which comprises a basically cylindrical geometry with basically rectangular cross-section. The EPA material, which according to the present embodiment forms a main body of the actuator 120, is denoted with reference sign 122. Electrically conductive electrodes 124a, 124b are provided, preferably in layer form, on opposing front surfaces of EPA material body 122 along the direction of extension and compression, and an electric control voltage (not shown) can thereby be applied to the electromechanic actuator 120 in order to alter its height H.
Also depicted by Figure 8 is an antenna element 110 that is rotatably mounted in its horizontal center section 110b, e.g. to a mounting element 130 as depicted by figure 1a. In its left axial end section 110a, the antenna element 110 is attached to the actuator 120 so that the actuator 120 may drive a rotational movement of said antenna element 110 around the axis A1 whenever its height H changes, i.e. corresponding to a control voltage applied to the electrodes 124a, 124b.
In order to reliably provide the antenna element 110 with an RF signal independent of a specific (rotational) position of the antenna element 110 with respect to the carrier element 102 (Figure 1a), a flexible RF-capable waveguide 112 such as a coaxial cable or the like is provided. According to an embodiment, the antenna element 110 may both be used for transmitting and/or receiving RF signals. Preferably, the RF waveguide is attached to the antenna element 110 close to the axis of rotation A1. According to a further embodiment, optionally, an insulating layer 126 may be provided on a top electrode 124b of the electromechanic actuator 120 to provide a galvanic isolation between the electrode 124b and a contact element 127 which is provided to make mechanical contact with said antenna element 110 and to apply said rotational driving force to the antenna element 110. According to an embodiment, the mechanical connection between the components 110, 120 by means of contact element 127 may be configured such that either tractive force (for pulling section 110a) and/or "propulsive" force (for pushing section 110a) may be transferred from the actuator 120 to the antenna element 110.
According to a further embodiment, the antenna element 110 may e.g. comprise an electrically conductive material layer, such as e.g. a metallized layer, to form a radiating element, as per se known in the art.
In the exemplarily described embodiments according to Fig. 1a, 1b, 3 to 6, only a single antenna element is shown, but according to further embodiments, rotational movement and driving could also be applied to antenna arrays, or one or more antenna matrix placed on a common plate 1100 (as depicted by Figure 2), allowing to commonly adjust a plurality of antenna elements. The principle according to the embodiments can be applied for mobile radio solutions e.g. in the L- and S-band, but also e.g. for mm-Wave applications (PtP (point to point), PMP (point to multipoint)), as well as any other antenna systems (either mobile or stationary) that may require manipulation of a beam pattern.
The principle according to the embodiments facilitates efficient adjustment of antenna beam patterns without requiring human interaction. Moreover, comparatively few electric energy is required for driving the electromechanic actuators, particularly EAP actuators. The antennas according to the embodiments may e.g. be used for general RF signal transmissions, cellular communications systems, point-to-point RF transmissions, point-to-multipoint transmissions and the like, where a, preferably dynamic, control of an antenna beam pattern is advantageous.
The description and drawings merely illustrate the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass equivalents thereof.
It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the invention. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

Claims

Antenna (100) comprising at least one antenna element (110) for transmitting and/or receiving radio frequency, RF, signals, wherein said antenna (100) comprises at least one electromechanic actuator (120) for moving said at least one antenna element (110) with respect to a further component (102, 110') of said antenna (100).
Antenna (100) according to claim 1, wherein said at least one antenna element (110) is rotatably attached to a carrier element (102) of said antenna (100), and wherein said at least one electromechanic actuator (120) is configured to drive a rotational movement of said at least one antenna element (110).
Antenna (100) according to one of the preceding claims, wherein a plurality of antenna elements (110_1, 110_2, 110_3) is attached on a common element carrier (1100), wherein said common element carrier (1100) is rotatably attached to a carrier element (102) of said antenna (100), and wherein said at least one electromechanic actuator (120) is configured to drive a rotational movement of said common element carrier (1100).
Antenna (100) according to one of the preceding claims, wherein said at least one antenna element (110) and/or said common element carrier (1100) is rotatably attached to a carrier element (102) of said antenna (100) such that said at least one antenna element (110) and/or said common element carrier (1100) can be rotated around at least two different axes.
Antenna (100) according to one of the preceding claims, wherein said at least one electromechanic actuator (120) comprises an electroactive Polymer material.
Antenna (100) according to one of the preceding claims, wherein two electromechanic actuators (120) are provided to drive said at least one antenna element (110).
Antenna (100e) according to one of the preceding claims, wherein a mounting pole (140) is provided on said carrier element (102) of said antenna (100), and wherein said at least one antenna element (110) is attached to said mounting pole (140).
Antenna (100e) according to claim 7, wherein said mounting pole (140) comprises at least one radio frequency waveguide (202) for contacting said antenna element (110).
Antenna (100) according to one of the preceding claims, wherein at least one antenna element (110) comprises a flexible waveguide (112) connected to said antenna element (110).
Antenna (100) according to one of the preceding claims, wherein said at least one electromechanic actuator (120) comprises a basically cylindrical geometry, particularly with a rectangular cross-section.
Antenna (100) according to one of the preceding claims, wherein at least two electromechanic actuators are provided which comprise different geometry and/or size.
Antenna (100) according to one of the preceding claims, wherein a spring force element (1220, 1222) is provided and positioned with respect to the antenna element (110) such that it can exert a spring force on the antenna element (110).
Method of operating an antenna (100) comprising at least one antenna element (110) for transmitting and/or receiving radio frequency, RF, signals, wherein said antenna (100) comprises at least one electromechanic actuator (120), and wherein said at least one antenna element (110) is moved (300) with respect to a further component (102, 110') of said Antenna (100) by means of said at least one electromechanic actuator (120).
Method according to claim 13, wherein said step of moving (300) comprises a step of rotating.
Method according to one of the claims 13 to 14, wherein a predetermined control voltage is applied to said at least one electromechanic actuator (120), preferably by means of electrodes attached to said at least one electromechanic actuator (120).