Antennas, frequency selective surfaces, vehicles, structures, and methods

Abstract

According to the present disclosure, there is provided an antenna comprising an antenna element comprising a magnetostrictive layer and a piezoelectric layer, the antenna further comprising a transducer arrangement comprising one or more transducers operable to generate a mechanical strain field within the antenna element to cause a displacement of a surface of the magnetostrictive layer.

Description

[Technical Field]

[0001] The present invention relates to antennas. More particularly, the present invention relates to antennas comprising a transducer arrangement for providing a surface displacement of a magnetostrictive layer of the antenna. Related frequency selective surfaces, vehicles, structures, and methods are also provided. [Background technology]

[0002] Wireless communication systems operating in the radio frequency range require antennas that convert electromagnetic waves into electrical currents representative of received signals and vice versa. The selective control of the electromagnetic (EM) waves received and / or transmitted by the antenna is limited. Furthermore, a common problem with classical antennas is the effect of heat loss.

[0003] Metasurface antennas are known. Metasurface antennas are designed to have specific signal reception / transmission characteristics. However, they typically have limited tunability. That is, a metasurface antenna can be designed to receive or transmit EM waves of a specific frequency with limited tuning of that frequency or bandwidth.

[0004] Frequency selective surfaces are designed to reflect, transmit, or absorb EM radiation of specific frequencies. However, they also have limited tunability of the selected frequencies. Furthermore, existing frequency selective surfaces have limited beam steering capabilities.

[0005] An exemplary object of exemplary embodiments of the present invention is to at least partially avoid or overcome one or more disadvantages of the prior art, whether identified herein or elsewhere, or to at least provide an alternative to existing antennas and methods. Summary of the Invention

[0006] According to a first aspect, there is provided an antenna comprising an antenna element comprising a magnetostrictive layer and a piezoelectric layer, the antenna further comprising a transducer arrangement comprising one or more transducers operable to generate a mechanical strain field in the antenna element to cause a displacement of a surface of the magnetostrictive layer.

[0007] In one example, in a receive mode, the magnetostrictive layer is configured to convert the magnetic field of the detected electromagnetic wave into a mechanical strain, and the piezoelectric layer is configured to receive the mechanical strain from the magnetostrictive layer and provide a voltage and / or charge output based thereon.

[0008] In one example, in a transmit mode, the piezoelectric layer is configured to receive a voltage and / or charge input and to impart a mechanical strain based thereon, and the magnetostrictive layer is configured to receive the mechanical strain to impart and output an electromagnetic wave based on the mechanical strain imparted by the piezoelectric layer.

[0009] In one example, the antenna element is operable to detect an environmental characteristic in an area surrounding the antenna element, and the transducer apparatus is operable to generate a mechanical strain field in the antenna element based on the environmental characteristic.

[0010] In one example, the piezoelectric layer has memristive, memcapacitive, or complex memimpedance properties.

[0011] In one example, the piezoelectric layer is arranged to be set to a defined non-volatile condition by application of a voltage and / or charge.

[0012] In one example, the piezoelectric layer is provided with electrical contacts to provide electrical connection to a drive circuit.

[0013] In one example, the transducer arrangement comprises a plurality of transducers operable to generate a mechanical strain field interference pattern within the antenna element.

[0014] In one example, the transducer device comprises one or more waveguides.

[0015] In one example, the antenna comprises an antenna element array comprising a plurality of antenna elements.

[0016] In one example, the antenna element array is a honeycomb antenna element array of hexagonal antenna elements.

[0017] In one example, one or more antenna elements are provided with one or more dedicated transducers.

[0018] In one example, one or more transducers of the transducer arrangement are operable to generate a mechanical strain field within the plurality of antenna elements.

[0019] In one example, the antenna further comprises one or more reflectors configured to reflect the mechanical strain waves generated by the one or more transducers. The one or more reflectors may be one or more acoustic reflectors.

[0020] According to a second aspect, there is provided a frequency selective surface comprising an antenna according to the first aspect.

[0021] In one example, the transducer device is operable to adjust a frequency selective surface.

[0022] According to a third aspect, there is provided a vehicle or structure comprising an antenna according to the first aspect or a frequency selective surface according to the second aspect.

[0023] According to a fourth aspect, there is provided a method of manufacturing an antenna, the method comprising providing an antenna element comprising a magnetostrictive layer and a piezoelectric layer, and a transducer arrangement comprising one or more transducers operable to generate a mechanical strain field in the antenna element to cause a displacement of a surface of the magnetostrictive layer.

[0024] It will of course be understood that features described in relation to one aspect of the invention may be incorporated in other aspects of the invention, and in particular the method of the fourth aspect may comprise any or all of the features of the first to third aspects, as desired or appropriate.

[0025] Other preferred and advantageous features of the present invention will become apparent from the following description.

[0026] Embodiments of the present invention will now be described, by way of example only, with reference to the figures, in which: [Brief explanation of the drawings]

[0027] [Figure 1] Antenna is shown. [Figure 2] 1 shows an antenna with an array of antenna elements. [Figure 3] 1 shows a frequency selective surface. [Figure 4] Indicates a vehicle. [Figure 5] Show the structure. [Figure 6] The principle of the general method is shown. DETAILED DESCRIPTION OF THE INVENTION

[0028] In summary, antennas are provided with the ability to shape the antenna surface geometry by generating mechanical distortion fields within the antenna. Receiving or transmitting electromagnetic (EM) waves using an antenna with a particular surface geometry generates a corresponding antenna radiation pattern.

[0029] 1, there is shown an antenna 10. The antenna 10 comprises an antenna element 100. The antenna element 100 comprises a magnetostrictive layer 102 and a piezoelectric layer 104. The magnetostrictive layer 102 and the piezoelectric layer 104 can be said to be "coupled," as will become apparent from the following description of receive and transmit operations.

[0030] The antenna 10 receives and transmits electromagnetic waves at its acoustic resonant frequency via the magnetoelectric effect. During receive operation of the antenna 10, the magnetostrictive layer 102 is configured to convert the magnetic field of the detected electromagnetic wave into a mechanical strain that is received by the piezoelectric layer 104. The piezoelectric layer 104 provides a voltage and / or charge output based on the strain received from the magnetostrictive layer 102. Specifically, in receive mode, the magnetostrictive layer 102 may sense the H component of the electromagnetic wave, which induces a vibration strain that is transmitted to the piezoelectric layer 104. The piezoelectric layer 104 may then provide a voltage and / or charge output.

[0031] Conversely, during a transmit operation of the antenna 10, the piezoelectric layer 104 is configured to receive a voltage and / or charge input and, based thereon, produce a mechanical strain. Such voltage and / or charge input may originate from the antenna 10 itself or from an external component of the antenna system. Although not illustrated in the figures, the piezoelectric layer 104 may be provided with electrical contacts to provide electrical connection to a drive circuit. The magnetostrictive layer 102 is then configured to receive the mechanical strain produced by the piezoelectric layer 104 and, based thereon, produce and output an electromagnetic wave. Specifically, the piezoelectric layer 104 may receive an alternating voltage and / or charge input and produce an oscillating mechanical strain. In response to the mechanical excitation, the magnetostrictive layer 102 may then induce magnetization oscillations or magnetic currents that radiate electromagnetic waves and, thus, transmit a signal.

[0032] Importantly, the antenna further comprises a transducer arrangement 106. The transducer arrangement 106 comprises one or more transducers 108. The one or more transducers 108 are operable to generate a mechanical strain field within the antenna element 100, resulting in a displacement of the surface of the magnetostrictive layer 102. The one or more transducers 108 may be surface acoustic wave resonators. The one or more transducers 108 may comprise one or more piezoelectric elements. The one or more transducers 108 may also be referred to as "acoustic actuators" operable to generate vibrations within the antenna element 100 by providing acoustic energy. It is noted that the transducers 108 are operable to generate a mechanical strain field, resulting in a displacement of the magnetostrictive layer 102, although it will be understood that a displacement of the piezoelectric layer 104 also occurs.

[0033] Displacement of the surface of the magnetostrictive layer 102 due to the generation of a mechanical strain field by the one or more transducers 108 affects the generation of or response to mechanical strain within the magnetostrictive layer 102. For the avoidance of doubt, the mechanical strain utilized to generate or receive electromagnetic waves is not the same as the mechanical strain field generated by the one or more transducers 108. It will be understood that while the magnetoelectric effect (i.e., in receive or transmit mode) utilizes mechanical strain to receive and transmit electromagnetic waves using the antenna 10, the present antenna 10 advantageously also utilizes the mechanical strain field provided by the one or more transducers 108 to control the antenna radiation pattern (i.e., to affect the mechanical strain in receive or transmit mode). That is, the antenna 10 still operates utilizing mechanical strain in the absence of the one or more transducers 108, but the one or more transducers generate a mechanical strain field that affects the response of the antenna 10 to mechanical strain, as will be described in further detail herein.

[0034] As described above, the one or more transducers 108 are operable to generate a mechanical strain field within the antenna element 100. Operation of the one or more transducers 108 causes the surface of the antenna element 100 to vibrate and excite standing waves, which generates a surface pattern or field consisting of regions of relatively high (or higher) strain and relatively low (or lower) strain. That is, a mechanical strain field is created within the antenna element 100, comprising regions of high and low strain within the magnetostrictive layer 102.

[0035] In the transmit mode, regions of relatively high strain are difficult to excite, while regions of relatively low strain are easier to excite. Thus, when the magnetostrictive layer 102 receives mechanical strain from the piezoelectric layer 104, the induced magnetization oscillations in the high strain regions are smaller in magnitude than the induced magnetization oscillations in the low strain regions. In this manner, an antenna radiation pattern is formed consisting of regions of high and low electromagnetic wave emission. It will be appreciated that the antenna radiation pattern can thereby be controlled by controlling the mechanical strain field generated by one or more transducers 108, for example, by controlling or adjusting the size or location of the high and low strain regions.

[0036] Furthermore, in the receive mode, it also follows that regions of relatively high strain are difficult to excite, while regions of relatively low strain are easier to excite. Thus, when the H component of the detected electromagnetic wave induces an oscillating mechanical strain in the magnetostrictive layer 102, the magnetostrictive layer will exhibit a greater response in the low strain regions of the magnetostrictive layer 102 and a lesser response in the high strain regions of the magnetostrictive layer 102. In this manner, by controlling or adjusting the size or location of the high and low strain regions, the antenna 10 can be tuned to receive (i.e., detect) incident electromagnetic waves of particular frequencies.

[0037] 1 comprises a stacked arrangement of magnetostrictive layers 102 and piezoelectric layers 104. In other examples, the antenna element 100 may comprise multiple magnetostrictive layers 102 and / or piezoelectric layers 104. In one advantageous example, the antenna element 100 may comprise a single magnetostrictive layer 102 positioned or sandwiched between two piezoelectric layers 104. In another advantageous example, the antenna element 100 may comprise multiple pairs of magnetostrictive layers 102 and piezoelectric layers 104 disposed on top of each other (i.e., a stack of alternating magnetostrictive and piezoelectric layers). Such an arrangement advantageously provides a larger signal magnitude and therefore a larger device response in both receive and transmit modes.

[0038] In one example, the piezoelectric layer 104 has memristive, memcapacitive, or complex memimpedance properties. The piezoelectric layer 104 may be formed from or comprise a material having such properties. The entire piezoelectric layer 104 may have such properties, or regions of the piezoelectric layer 104 may be formed with such properties. The piezoelectric layer 104 having such properties is configured to be set to a nonvolatile condition by application of a voltage and / or charge. In particular, memristor materials exhibit nonvolatile memory properties and continuous conductance change properties, making them suitable for use in neuromorphic systems. Memristor materials can be compared to synapses in the brain.

[0039] The cellular mechanism underlying learning and memory in the human and animal brains is called long-term potentiation (LTP). LTP is the permanent strengthening of synapses based on recent activity patterns. These are patterns of synaptic activity that result in a long-lasting increase in signal transmission between two neurons. Short-term potentiation (STP) refers to the process by which synaptic transmission is temporarily enhanced. In this way, STP can be thought of as short-term memory. STP can transform into LTP through a process of repeated impressions, which involves many biological changes.

[0040] Generally, a memristor (i.e., a memristive device) is a two-terminal resistive switching device that can maintain its internal resistance state depending on the history of the applied voltage / current. The two terminals behave similarly to the axons and dendrites connecting the pre- and post-synaptic neurons, and the conductance of the switching layer corresponds to the synaptic weight. By changing the conductance of the memristor to a set state, the device can be used to realize the memory function of the human brain by simulating the transition from an unmemorized state to an STP state and an LTP state.

[0041] The piezoelectric layer 104 can be set to a predetermined condition by applying a voltage. Setting the piezoelectric layer 104 to a predetermined condition can comprise changing the conductance of the piezoelectric layer 104 by applying a voltage or charge. In particular, applying a voltage to the piezoelectric layer 104 can modify the resistance, conductance, or complex impedance of the memristor material contained in the piezoelectric layer 104, thereby achieving the memory function described above. The voltage applied to the piezoelectric layer 104 can be an external bias voltage / charge, or an internal charge introduced by the antenna 10 due to the piezoelectric effect.

[0042] The condition (or state) of the piezoelectric layer 104 may depend on the previous state, the amplitude of the applied voltage, and the acquisition time of the voltage / signal. For example, after application of a first voltage, the condition of the piezoelectric layer 104 may change from an initial state to a first state. If a second voltage is applied to the piezoelectric layer 104 after the first voltage is applied, the condition of the piezoelectric layer 104 may change from the first state to a second state.

[0043] The resistance, conductance, or complex impedance of the piezoelectric layer 104 can be altered based on at least one of the frequency and polarity of the applied voltage. For example, applying successive positive voltage pulses can change the conductance of the memristor material contained in the piezoelectric layer 104 from an initial state to a higher state. Conversely, applying negative voltage pulses can change the conductance of the memristor material 104 from an initial state to a lower state. The conductance of the memristor material can also be changed by modifying the duration of the applied voltage.

[0044] The piezoelectric layer 104 can be configured to retain a set condition after application of a voltage. As described above, a voltage can be applied to change the conductance of the memristor material contained in the piezoelectric layer 104 from an initial state to a higher state. This change in the conductance of the memristor material is retained for a period of time after the application of the voltage is stopped, thereby enabling non-volatile memory operation of the memristor material. In other words, a constant voltage application is not required to change the conductance of the memristor material in the piezoelectric layer 104. By changing the conductance / resistance of the memristor material contained in the piezoelectric layer 104, the resonant frequency of the antenna 10 can be changed.

[0045] Retention time can be defined as the amount of time that the piezoelectric layer 104 retains its set state, e.g., the amount of time that the memristor material contained in the piezoelectric layer 104 retains its changed conductance state. Retention time can be increased by increasing at least one of the number of voltage pulses, the pulse width, and / or the pulse magnitude.

[0046] The piezoelectric layer 104 may be positioned to set to a predetermined condition before any receive and / or transmit operation of the antenna occurs, and in that way the antenna 10 may be pre-programmed or pre-set to a predetermined condition.

[0047] As described above, strain is generated by the magnetostrictive layer 102 by transducing the magnetic field of the detected electromagnetic wave, i.e., the signal being detected by the antenna 10. The piezoelectric layer 104 may be configured to provide a voltage output based on the received strain and the charge resulting from the settings of the piezoelectric layer 104. In this manner, the voltage output provided by the piezoelectric layer 104 may depend not only on the detected electromagnetic wave but also on the settings of the piezoelectric layer 104. For example, the voltage output may depend on the received strain resulting from the detected electromagnetic wave and the modified conductance of the memristor material included in the piezoelectric layer 104.

[0048] The piezoelectric layer 104 can be configured to provide a voltage output when the charge resulting from the received strain equals a predetermined threshold based on the conditions set for the piezoelectric layer. That is, the piezoelectric layer 104 can be configured to provide a voltage output only upon acquisition of a preprogrammed signal pattern. The piezoelectric layer 104 can be preprogrammed to respond to a specific signal pattern by using the memory capabilities of the memristor material contained therein. This can be achieved by setting the piezoelectric layer 104 to a predetermined condition that corresponds to the signal pattern the user wants to detect.

[0049] In particular, the process of signal recognition by the memristor material contained in the piezoelectric layer 104 may utilize the switching properties of the memristor. As described above, the application of a voltage may change the resistance, conductance, and complex impedance of the memristor material.

[0050] The transducer arrangement 106 comprises one or more waveguides 110 operable to control the propagation of a mechanical strain field. The operation of acoustic waveguides is well understood in the phononic field. Such waveguides 110 may be referred to as "phononic crystal waveguides." In the antenna 10, the waveguides 110 are operable to guide input acoustic waves from one or more transducers 108 to the antenna elements 100. Advantageously, this facilitates control of the propagation of the mechanical strain field and reduces losses of energy input to the antenna elements 100.

[0051] The antenna 10 illustrated in Figure 1 and described above is shown and described as comprising only a single antenna element 100. However, the antenna 10 may comprise an antenna element array (or "antenna element matrix") comprising multiple antenna elements. Such an arrangement is described below with reference to Figure 2. It will be appreciated that the principles of operation of the antenna 10 will be understood from the above description, together with further features described with reference to Figure 2.

[0052] Referring to FIG. 2(a), a plan view of the antenna 10 including an antenna element array 50 is shown. The antenna element array 50 includes a plurality of antenna elements 100a, 100b, 100c, etc. In the illustrated example, the antenna element array 50 includes an array of laterally disposed antenna elements 100a, 100b, 100c (i.e., antenna elements arranged side by side). In another example not illustrated, the antenna element array 50 includes an array of vertically disposed antenna elements 100a, 100b, 100c (i.e., antenna elements arranged in a stacked or layered manner). In one example, the antenna element array 50 may include a combination of laterally and vertically disposed antenna elements. Providing the antenna element array 50 is highly advantageous for a number of reasons. Generating a mechanical strain field is more effective in smaller-sized antenna elements 100 because the smaller-sized antenna elements 100 can be arranged to construct a larger-sized antenna 10. A further advantage is that the antenna 10 can be conformally mounted on the surface of a platform without the antenna being sensitive to the surface geometry of the platform, i.e., if the antenna 10 is formed from an array of (relatively small) antenna elements 100 arranged to form a larger antenna 10, the curvature or edge of the platform on which the antenna 10 is mounted does not affect the operation of the antenna.

[0053] In this example, the antenna element array 50 is a honeycomb antenna element array of hexagonal antenna elements 100a, 100b, and 100c. The shape of the antenna elements 100a, 100b, and 100c in the antenna element array 50 is highly advantageous for packing the elements into an array (i.e., providing an arrangement with a high density of antenna elements). Furthermore, the antenna 10 is not susceptible to proximity effects between the ground plane and the antenna elements. Therefore, many antenna elements 100a, 100b, and 100c can be closely packed. While hexagonal antenna elements provide the highest packing ratio, it will be appreciated that other antenna element shapes are, of course, possible and may actually be preferable or beneficial to the operation of the antenna 10 (e.g., generating a desired antenna radiation pattern or receiving electromagnetic waves at a particular frequency).

[0054] Referring to Figures 2(b) and 2(c), an antenna element 100a of the antenna element array 50 is shown in isolation in plan and cross-sectional side views, respectively. The magnetostrictive layer 102, piezoelectric layer 104, transducer 108, and reflector 112 can be seen in Figure 2(c). Although not illustrated in Figures 2(b) and 2(c), the transducer arrangement 106 also incorporates a waveguide, as described above with respect to Figure 1. A corresponding waveguide may be provided for each transducer.

[0055] Shown in Figure 2(b) are multiple transducers 108a, 108b, 108c of the transducer arrangement 106. The transducer arrangement 106 is present but not illustrated in Figure 2(a) for clarity.

[0056] The multiple transducers 108a, 108b, 108c are operable to generate mechanical distortion fields within the antenna element 100a. Furthermore, through the principles of constructive and destructive interference, the transducers 108a, 108b, 108c are operable to generate mechanical distortion field interference patterns within the antenna element 100a. In this manner, regions of high distortion (due to constructive interference) and regions of low distortion (due to destructive interference) can be generated within the magnetostrictive layer 102.

[0057] As shown in FIG. 2(b), one or more reflectors 112a, 112b, and 112c are also provided. The reflectors 112a-112c are configured to reflect the mechanical strain waves generated by one or more of the transducers 108a-108c. In this manner, the reflectors 112a-112c function to generate constructive and destructive interference of acoustic waves (by reflecting the vibrations emanating from the transducers), thereby generating a mechanical strain field interference pattern within the antenna element 100a. Furthermore, the reflectors 112a-112c are highly advantageous in that they allow for a reduction in the number of transducers required, thereby reducing the power consumption of the antenna 10.

[0058] In one example, one or more of the antenna elements 100 a, 100 b, 100 c are provided with one or more dedicated transducers. A dedicated transducer may be a transducer positioned to generate a mechanical strain field within one particular antenna element. In this way, when addressing an antenna element 100 a of the array 50, the dedicated transducer may be operated to generate a mechanical strain field within that particular antenna element 100 a. This situation may be similar across an array, with each element 100 a having one or more dedicated transducers. This is advantageous for simplifying the addressing of the antenna elements and increasing control over the generated mechanical strain fields.

[0059] In contrast, in another example, one or more transducers of the transducer arrangement 106 are operable to generate mechanical strain fields within multiple antenna elements (e.g., 100a, 100b). In a particular example, transducer 108a may be operable to generate a mechanical strain field within antenna element 100a and adjacent antenna element 100c. Furthermore, transducer 108b may be operable to generate a mechanical strain field within antenna element 100a and adjacent antenna element 100b. Advantageously, this structure provides greater control over the propagation of the mechanical strain field. Additionally, and importantly, this results in a simpler structure and reduced power consumption, even though more complex schemes may be required for addressing specific antenna elements.

[0060] In a further non-illustrated example, the antenna arrangement may comprise two or more antennas 10 stacked vertically (i.e., on top of each other). Advantageously, this allows the possibility of having two or more beams aligned in series, i.e., having multiple focal points. Such an arrangement facilitates depth sensing for each antenna element stack.

[0061] In an exemplary application of the antenna 10, the antenna 10 may be operable to detect environmental characteristics (or conditions) in an area surrounding the antenna element 100. The environmental characteristics may be weather conditions or the moisture content of the air, etc. The transducer apparatus 106 may be operable to generate a mechanical strain field within the antenna element 100 based on the environmental characteristics. The transducer apparatus 106 may be operable to generate a mechanical strain field within the antenna element 100 to match the radar appearance of the area surrounding the antenna element 100. That is, the antenna 10 operates to match the radar appearance of the environment in which the antenna 10 is located. The electromagnetic signature of the antenna 10 may change in real time to provide low observability of the platform (e.g., vehicle or structure) on which the antenna 10 is located in both stationary and moving conditions. Each antenna element 100 may perform this function, or alternatively, the antenna 10 as a whole may perform this function.

[0062] Referring to FIG. 3 , a frequency selective surface 300 is shown. The frequency selective surface 300 comprises the antenna 10. The transducer device 106 is operable to tune the frequency selective surface 300. Highly advantageously, the antenna 10 may be used as or in a frequency selective surface, overcoming the problems of conventional frequency selective surfaces. Conventional frequency selective surfaces have fixedly shaped apertures or patches across their surface that act as bandpass or bandstop filters for specific frequencies of electromagnetic radiation. It will be appreciated that conventional frequency selective surfaces have defined, non-tunable frequencies of interest. Instead, the present structure allows the antenna 10 to provide broadband control through control and adjustment of the mechanical strain field by the transducer device 106. Furthermore, the present structure provides beam steering capabilities. That is, control of the surface geometry of the antenna 10 allows control of the array resonance, absorption, transmission, and reflection properties of the antenna 10. Furthermore, interaction with polarized electromagnetic signals is easily controlled.

[0063] 4, a vehicle 400 is shown. The vehicle 400 includes an antenna 10 or a frequency selective surface 300. The antenna 10 or the frequency selective surface 300 may be conformally mounted on a surface of the vehicle 400. The vehicle 400 may be an aircraft, a watercraft, a spacecraft (such as a satellite), and / or a road vehicle.

[0064] 5, a structure 500 is shown. The structure 500 comprises an antenna 10 or a frequency selective surface 300. The antenna or frequency selective surface 300 may be conformally disposed on a surface of the structure 500. The structure 500 may be a building and / or a structure.

[0065] 6, there is shown a method of manufacturing the antenna 10. Step 610 comprises providing an antenna element comprising a magnetostrictive layer, a piezoelectric layer, and a transducer arrangement comprising one or more transducers operable to generate a mechanical strain field within the antenna element to effect a displacement of the surface of the magnetostrictive layer.

Claims

1. An antenna, a magnetostrictive layer; a piezoelectric layer; an antenna element comprising: The antenna is one or more transducers operable to generate a mechanical strain field within the antenna element to cause a displacement of a surface of the magnetostrictive layer; The antenna further comprises a transducer device comprising:

2. 2. The antenna of claim 1, wherein in a receive mode, the magnetostrictive layer is configured to convert a magnetic field of a detected electromagnetic wave into a mechanical strain, and the piezoelectric layer is configured to receive the mechanical strain from the magnetostrictive layer and provide a voltage and / or charge output based thereon.

3. 3. The antenna of claim 1, wherein in a transmit mode, the piezoelectric layer is configured to receive a voltage and / or charge input and to impart a mechanical strain based thereon, and the magnetostrictive layer is configured to receive the mechanical strain to impart and output an electromagnetic wave based on the mechanical strain imparted by the piezoelectric layer.

4. 4. The antenna of claim 3, wherein the antenna element is operable to detect an environmental characteristic in an area surrounding the antenna element, and the transducer arrangement is operable to generate the mechanical strain field in the antenna element based on the environmental characteristic.

5. 5. An antenna according to any one of claims 1 to 4, wherein the piezoelectric layer has memristive, memcapacitive or complex memimpedance properties, and optionally the piezoelectric layer is arranged to be set to a defined non-volatile condition by application of a voltage and / or charge.

6. An antenna according to any preceding claim, wherein the transducer arrangement comprises a plurality of transducers operable to generate a mechanical strain field interference pattern within the antenna element.

7. An antenna according to any one of the preceding claims, wherein the transducer arrangement comprises one or more waveguides.

8. An antenna according to any preceding claim, comprising an antenna element array comprising a plurality of antenna elements.

9. 9. The antenna of claim 8, wherein the antenna element array is a honeycomb antenna element array of hexagonal antenna elements.

10. 10. An antenna according to claim 8 or 9, wherein one or more antenna elements are provided with one or more dedicated transducers.

11. An antenna according to any one of claims 8 to 10, wherein one or more transducers of the transducer arrangement are operable to generate a mechanical strain field within a plurality of antenna elements.

12. The antenna of any one of claims 1 to 11, further comprising one or more reflectors configured to reflect mechanical strain waves generated by the one or more transducers.

13. A frequency selective surface comprising an antenna according to any one of claims 1 to 12, optionally wherein the transducer arrangement is operable to tune the frequency selective surface.

14. A vehicle or structure comprising an antenna according to any one of claims 1 to 12 or a frequency selective surface according to claim 13.

15. 1. A method of manufacturing an antenna, comprising: a magnetostrictive layer, and Piezoelectric layer an antenna element comprising: one or more transducers operable to generate a mechanical strain field within the antenna element to cause a displacement of a surface of the magnetostrictive layer; a transducer device comprising: A method comprising: providing

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