Apparatus and process for wireless energy harvesting

Abstract

A dual wireless energy transfer device can be configured to use multiple different energy sources (e.g. use magnetic field and acoustic intensity) to provide higher power density and / or quicker battery charging and / or capacitor charging within safety limits for human exposure. Some embodiments can utilize radially poled piezoelectric disks laminated between the magnetostrictive layers that can be configured to provide a tolerance to angular misalignment in the x-y plane (parallel to the diameter of the device) as well. Some embodiments can be configured so that ultrasound waves and / or a magnetic field can be used to help power or recharge a device. Other embodiments can be configured to utilize other types of acoustic waves and / or magnetic field combinations for charging of a device (e.g. battery charging, capacitor charging, etc.).

Description

[0001] APPARATUS AND PROCESS FOR WIRELESS ENERGY HARVESTING

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Patent Application No. 63 / 609,482, filed on December 13, 2023.

[0004] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0005] This invention was made with government support under Grant Nos. EECS 1904811 and EEC 1916707 awarded by the National Science Foundation. The Government has certain rights in the invention.

[0006] FIELD

[0007] This innovation relates to devices and methods for wireless energy harvesting. Embodiments can be configured to charge a battery or store voltage and / or current in response to exposure to one or more wireless energy sources (e.g. magnetic fields and / or acoustic sound waves, etc.).

[0008] BACKGROUND

[0009] Energy harvesting can be used for supplying power in many applications such as electronics, sensor networks and Internet of Things (loT) devices. U.S. Patent Application Publication Nos. 2018 / 0198321 and 2015 / 0335285 and U.S. Patent Nos. 8,082,041 and 10,966,776 disclose energy harvesting approaches.

[0010] SUMMARY

[0011] We have found that there can be significant challenges in designing energy harvesting devices with high enough power density using a single source for energy harvesting (e.g. only use of a magnetic field or only use of ultrasound waves). We determined that since the magnitude of the input source has to be kept low in order to meet the human body safety limits, the output from energy harvesting device using a single input is also typically low to meet the powering requirements. For instance, an Institute of Electrical and Electronics Engineers (IEEE) standard for operational frequency of ~250 kHz is as follows: the applied alternating current (AC) magnetic field strength <5.5 oersted (Oe) root mean square (RMS) (at an implant depth of 30 mm) and a direct current (DC) magnetic field strength < 1670 Oe. Depending on the type of peak-to-peak number that may be selected, the AC magnetic field strength can be < 11 Oe RMS. As another example, United States Food and Drug Administration (FDA) regulations limit ultrasound intensity exposure on the human body to a maximum of 720 milliWatts per square centimeter (mW / cm2) for medical diagnostic purposes. Exceeding this threshold can result in tissue damage, abnormal cell migration, and neurodegenerative diseases.

[0012] We determined that it is not practical to enhance the magnitude of output power by increasing the surface area of the device as there is space constraint in most of the intended applications. We further determined that increasing the input source magnitude is not a desired option because if the input magnetic field or ultrasound energy are above human safety limits, then it may cause irreversible damage to human cells. Often, energy harvesting devices are designed to utilize a single input source and thus do not exhibit any significant advantages under exposure to dual input sources (e.g. they cannot harvest energy from multiple input sources at the same time). However, we conceptualized that if the same energy harvesting device can respond to two or more sources than the power density can be significantly enhanced without having to increase the surface area and without having to increase the amplitude of the input source energy.

[0013] We have developed embodiments of a multi-mode energy harvesting device. Some embodiments can be configured as a disk-shaped multi-mode energy harvester using a magnetoelectric mechanism that can provide not only higher output power within human body safety limits, but can also be designed to be insensitive to the source alignment. Embodiments can also utilize acoustic or ultrasound waves as a second energy source and utilize both magnetic field exposure and acoustic or ultrasound wave exposure to harvest energy form both sources at the same time. Please note that an acoustic wave above 20 kHz is referred to as ultrasound wave. We have experimented with both acoustic waves and ultrasound waves (which is a type of acoustic wave) and they will both be referred to throughout the document.

[0014] As discussed herein, we have demonstrated embodiments of our dual wireless energy transfer device that can use magnetic field and ultrasound intensity to achieve quick battery charging within safety limits for human exposure to the ultrasound waves and magnetic field. Some embodiments can utilize radially poled piezoelectric disks that can be configured to provide a tolerance to angular misalignment in the x-y plane (parallel to the diameter of the device) or y-z plane. Embodiments can be provided for a number of different practical applications in which a source is often fixed (for example, attached to a wall, etc.) but the harvester can move in the x-y plane (for example, a patient in a bed within a room by the wall on which the source is fixed, etc.). Embodiments of the dual energy harvesters can enable powering the sensors or other electronic devices that can be embedded inside or outside an animal body (e.g. body of a human, body of a pet, body of a farm animal, etc.).

[0015] Some embodiments of our fabricated magnetoelectric (ME) device can utilize high power piezoelectric ceramics with a composition of Cu-Mn-Pb(In,Nb)O3-Pb(Mg,Nb)O3-PbTiO3. This composition has been found to exhibit high piezoelectric coefficient along with high mechanical quality factor and low dielectric loss factor. A piezoelectric disk-transducer can be sandwiched between magnetostrictive layers (e.g. Metglas material with low direct current (DC) bias) to respond to both the magnetic and acoustic energy sources. To the best of our knowledge, this is the first demonstration of a magnetic field and ultrasound induced dual generator (MUDG) device capable of simultaneous energy harvesting for wireless power transfer. Embodiments of our ME can be configured as a MUDG device. The MUDG device can also refer to a type of magnetic field and acoustic wave induced dual generator (MADG) device. For instance, a MUDG device can be a type of MADG device configured for use via the ultrasound range of acoustic waves. Other types of MADG devices can be configured to use other types of acoustic waves or a combination of different types of acoustic waves (e.g. embodiments may not just utilize ultrasound waves, may utilize a combination of acoustic waves that do not include ultrasound waves, or may utilize another type of acoustic wave that is not an ultrasound wave, etc.). For example, acoustic waves that may be formed via vibrations that occur as a result of a vehicle driving on a road, acoustic waves that may occur via vibrations in shoes as a person is jogging or walking, acoustic waves that may occur via vibrations in equipment used in manufacturing, etc. may be utilized in some embodiments instead of or in addition to ultrasound waves.

[0016] As discussed herein, some embodiments of our MUDG device have been demonstrated to charge a 3V Li-ion battery with 1 mAh capacity at a rate of - 1.67 mC / s in a porcine tissue medium under ex-vivo conditions. We believe embodiments of our dual energy transfer system (which can utilize an embodiment of our MUDG device) can provide a platform for the next generation of biomedical implantable devices, loT sensors, and remote sensors that can be positioned in or near buildings or other facilities, and structural health monitoring sensors.

[0017] Also, embodiments of our MUDG have been demonstrated to provide hybrid energy harvesting technology using both ultrasound and magnetic energy under water / tissue (ex-vivo) mediums. Some embodiments of the MUDG can have a disk architecture that comprises of a high energy density novel Mn02 and CuO co-doped Pb(ln,Nb)O3-Pb(Mg,Nb)O3-PbTiO3 (P1N- PMN-PT) piezoelectric disk-shaped transducer sandwiched between magnetostrictive Metglas layers. Embodiments of the MUDG can be configured to produce ultrahigh root mean square (RMS) power of -52.1 mW with power density of -597 mW / cm3at -500 pT magnetic field and 675 mW / cm2ultrasound intensity. This is the highest reported value compared to all the prior devices with applied input under safety limit. Results from experimentation we have performed demonstrate that embodiments of our MUDG can overcome the limitations of traditional wireless power systems for human body applications as well as other applications and can provide a new platform for powering electronics. Some embodiments can be configured to provide advantages of ultra-high-power density, small size, and tolerance to angular misalignment (x-y plane). These types of advantages have been confirmed via systematic studies we performed that are discussed herein related to device optimization for some specific applications, the powering of electronics, transcutaneous transmission, power transfer ex-vivo, and safety analysis, that evaluated the potential of different embodiment of our MUDG device to be utilized in various different applications.

[0018] As can be understood from our disclosure herein, embodiments of our MADG device can provide one or more advantages. For example, some embodiments can provide a wireless energy transfer that includes providing at least one non-contact power source for the devices when the device is embedded in a structure, a body, an animal, or an object. For example, embodiments can permit a non-contact power source to be utilized to help power a sensor deployed inside a bed to measure pressure changes. As another example, an embodiment can be configured to be deployed inside the human body or inside the body of another type of animal for regulating the oxygen flow in the animal. In both of these non-limiting examples, once the sensor or device is installed, it is not accessible and thus there cannot be direct contact with a power source. However, embodiments can permit the device to be recharged for continuous use even though the device is inaccessible. And we have found that embodiments can be configured to permit such recharging to occur relatively quickly.

[0019] In a first aspect, an apparatus for wireless energy harvesting is provided. The apparatus can include at least one magnetic field and acoustic wave induced dual generator (MADG) device configured to generate voltage and / or current in response to exposure to a magnetic field and acoustic waves.

[0020] In some embodiments, the acoustic waves are ultrasound waves or can include ultrasound waves.

[0021] In a second aspect, the magnetic field can have a particular type of configuration. For instance, the magnetic field can be an alternating current (AC) magnetic field strength that is less than or equal to 15 Oe. As another example, the magnetic field can be a direct current (DC) magnetic field having a strength that is less than or equal to 2000 Oe.

[0022] In a third aspect, the acoustic waves can include ultrasound waves. In some embodiments, the ultrasound waves can have an ultrasound intensity that is no more than 750 milliWatts per square centimeter (mW / cm2) for the ultrasound waves.

[0023] In a fourth aspect, the MADG device can include a body having at least one piezoelectric layer between a first side and a second side. The first side can have a plurality of magnetostrictive layers and resin layers and the second side can have a plurality of magnetostrictive layers and resin layers.

[0024] In some embodiments, the first side has between 3 and 6 magnetostrictive layers and between 3 and 6 resin layers and the second side has between 3 and 6 magnetostrictive layers and between 3 and 6 resin layers.

[0025] In some embodiments, the piezoelectric layer can be comprised of Mn02 and CuO codoped Pb(In,Nb)Oa-Pb(Mg,Nb)O3-PbTiO3 (PIN-PMN-PT) material. In other embodiments, another type of suitable material may be utilized.

[0026] In a fourth aspect, the piezoelectric layer of the MADG device can have a disk-shaped transducer, a square shaped transducer, a rectangular shaped transducer, a disk shaped layer, a square shaped layer, or a rectangular shaped layer.

[0027] In a fifth aspect, the MADG device can include a coating that encapsulates the piezoelectric layer, the first side, and the second side. In some embodiments, coating can be a polydimethylsiloxane (PDMS) coating or a chlorinated poly(para-xylylene) polymer coating.

[0028] In a sixth aspect, the at least one piezoelectric layer can be lead-free.

[0029] In a seventh aspect, the plurality of resin layers of the first side can include nanoparticles of magnetic material.

[0030] In an eighth aspect, the plurality of resin layers of the second side can include nanoparticles of magnetic material.

[0031] In a ninth aspect, the MADG device can also include an electrode attached to the first side and / or an electrode attached to the second side. In some embodiments, the electrode attached to the first side can be comprised of a metal paste and / or the electrode attached to the second side can be comprised of a metal paste. In some embodiments, the metal paste is platinum (Pt) paste, silver / palladium (Ag / Pd) paste, Ag past, Au paste, Ni paste, and / or Cu paste.

[0032] In a tenth aspect, the at least one piezoelectric layer can be comprised of a biopolymeric material. In some embodiments, the biopolymeric material can be compatible with a body of an animal.

[0033] In an eleventh aspect, the MADG device can be sized to be a nanoparticle.

[0034] In a twelfth aspect, the apparatus can include a battery connected to the MADG device; and / or at least one capacitor connected to the MADG device; and / or at least one supercapacitor connected to the MADG device.

[0035] In a thirteenth aspect, the MADG device can be integrated into an implantable medical device (IMD) or can be connected to an electrical energy storage device of a remote device for recharging the electrical energy storage device. In some embodiments, the electrical energy storage device can be a rechargeable battery.

[0036] In a fourteenth aspect, the apparatus of the first aspect can include one or more features of the second aspect, third aspect, fourth aspect, fifth aspect, sixth aspect, seventh aspect, eighth aspect, ninth aspect, tenth aspect, eleventh aspect, twelfth aspect, and / or thirteenth aspect. Embodiments can also include other elements or features. Examples of other elements or features can be appreciated from the exemplary embodiments discussed herein, for instance.

[0037] In a fifteenth aspect, a process for wireless energy harvesting is provided. Embodiments of the process can include generating voltage in response to exposure to a magnetic field. The magnetic field can have an alternating current (AC) magnetic field strength that is less than or equal to 5.5 Oe or having a direct current (DC) magnetic field strength that is less than or equal to 2000 Oe. The method can also include generating voltage in response to exposure to ultrasound waves. The ultrasound waves can have an ultrasound intensity that is no more than 750 milliwatts per square centimeter (mW / cnr). The generating of the voltage in response to the exposure to the magnetic field and the generating of the voltage in response to the exposure to the ultrasound waves can occur simultaneously via a magnetic field and ultrasound induced dual generator (MUDG) device.

[0038] In a sixteenth aspect, the process can include other steps. For example, the process can include positioning the MUDG device in a body of an animal or integrating the MUDG device into a remote device positionable in or adjacent to a facility.

[0039] As another example, the process can include fabricating the MUDG device so that the MUDG device comprises a body having a piezoelectric layer between a first side of the body and a second side of the body. The first side can have a plurality of magnetostrictive layers and resin layers and the second side can have a plurality of magnetostrictive layers and resin layers.

[0040] In some embodiments, the fabricated MUDG device can be an embodiment of the MADG device.

[0041] In some embodiments, the piezoelectric layer is comprised of Mn02 and CuO co-doped Pb(In,Nb)O3-Pb(Mg,Nb)O3-PbTiCh (PIN-PMN-PT) material. In other embodiments, the piezoelectric layer can be comprised of PZT material, PMN-PZT material, PMN-PT material, BT material or PZN-PT material.

[0042] In some embodiments, the fabricating of the MUDG device is performed so that the MUDG device also comprises a coating that encapsulates the piezoelectric layer, the first side, and the second side.

[0043] Embodiments of the process can also (or alternatively), include feeding the generated voltage generated via the magnetic field and the ultrasound waves to a battery to recharge the battery or to an electrical energy storage device to recharge the electrical energy storage device. In some embodiments, the electrical energy storage device can be a rechargeable battery.

[0044] In a seventeenth aspect, the process of the fifteenth aspect can include one or more features of the sixteenth aspect and / or utilize an embodiment of the MADG device.

[0045] Embodiments of the process can also include other features or elements. Examples of other elements or features can be appreciated from the exemplary embodiments discussed herein, for instance.

[0046] In a seventeenth aspect, a process for wireless energy harvesting is provided that includes generating voltage in response to exposure to a magnetic field and also generating voltage in response to exposure to acoustic waves simultaneously via a magnetic field and acoustic wave induced dual generator (MADG) device.

[0047] The process for wireless energy harvesting can also include other steps or features. For example, the process can include feeding the generated voltage generated via the magnetic field and the acoustic waves to an electrical energy storage device to recharge the electrical energy storage device. As another example, the process can include generating voltage in response to exposure to a magnetic field via the MADG device for feeding to an electrical energy storage device wherein the magnetic field has an alternating current (AC) magnetic field strength that is less than or equal to 5.5 Oe or has a direct current (DC) magnetic field strength that is less than or equal to 1670 Oe and the process also includes generating voltage in response to exposure to acoustic waves via the MADG device for feeding to the electrical energy storage device.

[0048] Other embodiments of the process may also utilize other features or elements. Examples of other elements or features can be appreciated from the exemplary embodiments discussed herein, for instance.

[0049] Other details, objects, and advantages of the invention will become apparent as the following description of certain present preferred embodiments thereof and certain present preferred methods of practicing the same proceeds.

[0050] BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Exemplary embodiments of apparatuses and processes for wireless energy harvesting, exemplary embodiments of our magnetic field and acoustic wave induced dual generator (MADG) devices and methods of making and using the same are shown in the accompanying drawings. It should be appreciated that like reference numbers used in the drawings may identify like components.

[0052] Figure 1 (which can also be referred to as Fig. 1) is a schematic illustration of a first exemplary embodiment of an apparatus for wireless energy harvesting. This exemplary embodiment can utilize an exemplary embodiment of a MUDG device, which is an exemplary embodiment of a MADG device.

[0053] Figure 2 (which can also be referred to as Fig. 2) is an exploded view of an exemplary embodiment of a MUDG device that can be utilized in embodiments of the apparatus for wireless energy harvesting and embodiments of our process for wireless energy harvesting.

[0054] Figure 3 (which can also be referred to as Fig. 3 ) is schematic illustration of an exemplary embodiment of an apparatus for wireless energy harvesting that can utilize an embodiment of our process for wireless energy harvesting within an animal Al (e.g. a pig, a human, etc.) for simultaneously harvesting energy from a magnetic field and ultrasound wave exposed to the animal and / or passed through the animal Al .

[0055] Figure 4 (which can also be referred to as Fig. 4) is a schematic illustration of an experimental setup of magnetic field energy harvesting for evaluation of an embodiment of our apparatus and process for wireless energy harvesting utilizing an embodiment of our MUDG device.

[0056] Figure 5 (which can also be referred to as Fig. 5) is a graph illustrating the voltage coefficient of exemplary embodiments of MUDG devices as a function of direct current (DC) magnetic field strength in air medium.

[0057] Figure 6 (which can also be referred to as Fig. 6) is graph illustrating the frequency dependent output voltage of exemplary embodiments of MUDG devices in air medium. As indicated in Figure 6, the output voltage is a peak voltage (Vp).

[0058] Figure 7 (which can also be referred to as Fig. 7) is a graph illustrating a theoretical verification of voltage distribution varying with frequency of an exemplary embodiment of our MUDG device (e.g. MUDG5). Figure 8 (which can also be referred to as Fig. 8) is a piezo-potential distribution found in the MUDG5 device at a 100 microtesla (pT) AC magnetic field validated via a finite element method.

[0059] Figure 9 (which can also be referred to as Fig. 9) is a graph illustrating the external load dependent generated output power of different exemplary embodiments of our MUDG device at 100 pF AC magnetic field strength in air medium.

[0060] Figure 10 (which can also be referred to as Fig. 10) is a graph illustrating frequency dependent output voltage under external load of the exemplary embodiments of our MUDG devices at 100 pT AC magnetic field in water medium.

[0061] Figure 11 (which can also be referred to as Fig. 11) is a graph illustrating the output power under external load of the MUDG devices at 100 pT AC magnetic field in water medium.

[0062] Figure 12 (which can also be referred to as Fig. 12) is a graph illustrating maximum output power generated from different exemplary embodiments of our MUDG devices at different alternating current (AC) magnetic fields (100-500 pT) in a water medium.

[0063] Figure 13 (which can also be referred to as Fig. 13) is a schematic illustration of an experimental setup of magnetic field energy harvesting for evaluation of an embodiment of our apparatus and process for wireless energy harvesting utilizing an embodiment of our MUDG device.

[0064] Figure 14 (which can also be referred to as Fig. 14) is a graph illustrating the applied input voltage through a commercial transducer and generated output voltage from the MUDG3 device obtained via experimentation work discussed herein.

[0065] Figure 15 (which can also be referred to as Fig. 15) is a graph illustrating the frequency dependent output voltage of different embodiments of our MUDG devices during ultrasound energy harvesting.

[0066] Figure 16 (which can also be referred to as Fig. 16) is a graph of a theoretical validation of output voltage dependent frequency of our MUDG5 device under 137 mW / cm2ultrasound intensity based on a finite element method (FEM) analysis. Figure 17 (which can also be referred to as Fig. 17) is a piezo-potential distribution of the MUDG5 device under 137 mW / cm2ultrasound intensity based on the FEM analysis.

[0067] Figure 18 (which can also be referred to as Fig. 18) is a graph illustrating the generated output power that was measured by varying external resistance at constant working frequency.

[0068] Figure 19 (which can also be referred to as Fig. 19) is a graph providing a comparison of the output power from the MUDG3 device in water and tissue medium.

[0069] Figure 20 (which can also be referred to as Fig. 20) is a graph illustrating the maximum generated power from different embodiments of our MUDG devices under ultrasound wave exposure of 675 mW / cm2.

[0070] Figure 21 (which can also be referred to as Fig. 21) is a graph illustrating output power for different embodiments of our MUDG devices at 5 mm, 10 mm and 15 mm distances from the ultrasound transducer.

[0071] Figure 22 (which can also be referred to as Fig. 22) is a schematic illustration of an experimental setup of magnetic field energy harvesting for evaluation of an embodiment of our apparatus and process for wireless energy harvesting utilizing an embodiment of our MUDG device.

[0072] Figure 23 (which can also be referred to as Fig. 23) is an illustration providing a perspective view of an exemplary scheme for dual energy harvesting under water via an embodiment of our MUDG device.

[0073] Figure 24 (which can also be referred to as Fig. 24) is a graph illustrating generated output voltage from embodiments of our MUDG devices under individual magnetic field / ultrasound technology and combined (magnetic and ultrasound) technologies (inset shows zoom graph).

[0074] Figure 25 (which can also be referred to as Fig. 25) is a graph illustrating the generation of output power in MUDG devices varying with external resistance under 200 pT magnetic field.

[0075] Figure 26 (which can also be referred to as Fig. 26) is a graph illustrating the generation of output power in MUDG devices varying with external resistance under 137 mW / cnr ultrasound intensity. Figure 27 (which can also be referred to as Fig. 27) is a graph illustrating the generated power from different embodiments of our MUDG devices varying with external load resistance under simultaneous magnetic field and ultrasound energy exposure.

[0076] Figure 28 (which can also be referred to as Fig. 28) is a graph illustrating the generated power variation with external resistance of different embodiments of our MUDG devices under 500 pT magnetic field.

[0077] Figure 29 (which can also be referred to as Fig. 29) is a graph illustrating the generated power variation with external resistance of different embodiments of our MUDG devices under 675 mW / cm2ultrasound intensity.

[0078] Figure 30 (which can also be referred to as Fig. 30) is a graph illustrating the generated power variation with external load resistance for different embodiment of our MUDG devices under 500 pT magnetic field and 675 mW / cm2ultrasound intensity based on simultaneous measurement.

[0079] Figure 31 (which can also be referred to as Fig. 31) is a graph illustrating the average root mean square (RMS) power density of the MUDG devices under different magnetic field and ultrasound intensities.

[0080] Figure 32 (which can also be referred to as Fig. 32) is a graph illustrating the charging capability of the MUDG5 device for 1, 4.4 and 10 millifarads (mF) capacitors under a 100 pT magnetic field and a 40 mW / cm2ultrasound intensity exposure.

[0081] Figure 33 (which can also be referred to as Fig. 33) is a graph illustrating the charging performance of the MUDG5 device for a 1 farad (F) supercapacitor.

[0082] Figure 34 (which can also be referred to as Fig. 34) is a graph illustrating the 1 milliampere- hour (mAh) lithium ion (Li-ion) battery charging characteristic using MUDG5 device under dual magnetic field and ultrasound intensity with or without transformer. A milliampere-hour is a unit that can also be referred to as a milliamp-hour.

[0083] Figure 35 (which can also be referred to as Fig. 35) is a graph illustrating the 11 mAh Li- ion and 33 mAh Li-ion battery charging characteristics using MUDG5 device under dual magnetic field and ultrasound intensity with or without transformer.

[0084] Figure 36 (which can also be referred to as Fig. 36) is a schematic drawing of an exemplary embodiment of our apparatus for wireless energy harvesting that can utilize an embodiment of our MUDG device to power a light array (e.g. a plurality of light emitting diodes (LEDs) via a bridge rectifier.

[0085] Figure 37 (which can also be referred to as Fig. 37) is a graph illustrating the power output of the MUDG5 device under simultaneous energy harvesting varying with external load resistance.

[0086] Figure 38 (which can also be referred to as Fig. 38) is a graph illustrating the power output of MUDG5 at 5 mm, 10 mm and 15 mm thick porcine tissue under 500 pT magnetic field and 675 mW / cm2ultrasound intensity.

[0087] Figure 39 (which can also be referred to as Fig. 39) is a graph illustrating the 1 mAh 3V Li-ion battery recharging characteristic under water and porcine tissue during simultaneous energy harvesting for the MUDG5 device.

[0088] Figure 40 (which can also be referred to as Fig. 40) is a graph illustrating the 3 mAh 3V Li-ion battery recharging characteristic and the 5 mAh 3 V Li-ion battery recharging characteristic under porcine tissue during simultaneous energy harvesting for the MUDG5 device.

[0089] Figure 41 (which can also be referred to as Fig. 41) is a graph illustrating the stability of performances of the MUDG5 device measured under tissue or water for a consecutive 170 hrs.

[0090] Figure 42 (which can also be referred to as Fig. 42) is a schematic flow chart illustrating an exemplary process for forming an exemplary embodiment of a MUDG device.

[0091] Figure 43 (which can also be referred to as Fig. 43) is an exploded perspective view of an exemplary embodiment of a MUDG device including photos of exemplary embodiments of a formed MUDG device.

[0092] Figure 44 (which can also be referred to as Fig. 44) is a graph illustrating the strain vs. DC magnetic field strength for different MUDG devices with different numbers of magnetostrictive layers.

[0093] Figure 45 (which can also be referred to as Fig. 45) is graph illustrating the variation of the piezomagnetic constant with DC magnetic field strength for different embodiments of our MUDG device.

[0094] Figure 46 (which can also be referred to as Fig. 46) is a schematic illustration of magnetic moment measurement set up for different MUDG devices using Vibrating Sample Magnetometer (VSM) measurements and graphs obtained from using VSM measurements for different exemplary embodiments of our MUDG devices.

[0095] Figure 47 (which can also be referred to as Fig. 47) is a graph illustrating a measured real impedance in air for different MUDG devices.

[0096] Figure 48 (which can also be referred to as Fig. 48) is a graph illustrating a measured imaginary impedance in water for different MUDG devices.

[0097] Figure 49 (which can also be referred to as Fig. 49) is a graph illustrating a half power bandwidth method for experimental estimation of the trend of quality factor (Q).

[0098] Figure 50 (which can also be referred to as Fig. 50) is a graph illustrating the trend of quality factor (Q) with a DC magnetic field for different embodiments of our MUDG device.

[0099] Figure 51 (which can also be referred to as Fig. 51) is a graph illustrating peak voltage variation with DC magnetic field for different embodiments of our MUDG device.

[0100] Figure 52 (which can also be referred to as Fig. 52) is a graph illustrating variation of frequency with DC magnetic field corresponding to the peak voltage for different embodiments of our MUDG device.

[0101] Figure 53 (which can also be referred to as Fig. 53) is a graph illustrating the generated voltage and power behavior with thickness ratio of different embodiments of our MUDG devices.

[0102] Figure 54 (which can also be referred to as Fig. 54) is a graph providing a comparison of output power with the number of magnetostrictive layers for embodiments of our MUDG devices.

[0103] Figure 55 (which can also be referred to as Fig. 55) is a schematic illustration of an experimental setup of magnetic field energy harvesting for evaluation of an embodiment of our apparatus and process for wireless energy harvesting utilizing an embodiment of our MUDG device. Figure 56 (which can also be referred to as Fig. 56) is a graph illustrating the variation of AC magnetic field strength (at constant DC bias) with the generated output voltage from our

[0104] MUDG5 device and constant frequency (250kHz).

[0105] Figure 57 (which can also be referred to as Fig. 57) is a graph illustrating a comparison of power with the number of magnetostrictive layers in different embodiments of our MUDG devices and other types of piezoelectric disks.

[0106] Figure 58 (which can also be referred to as Fig. 58) is a schematic illustration of an experimental setup of magnetic field energy harvesting for evaluation of an embodiment of our apparatus and process for wireless energy harvesting utilizing an embodiment of our MUDG device.

[0107] Figure 59 (which can also be referred to as Fig. 59) is graph illustrating a relationship between the input voltage and output voltage of MUDG5 at constant AC magnetic field (l OOpT) during ultrasound measurement.

[0108] Figure 60 (which can also be referred to as Fig. 60) is a graph illustrating the relationship between the AC magnetic field and output voltage of the MUDG5 device at constant input voltage (90Vp-p, which is 90 peak-to-peak voltage) applied to the ultrasound transducer during experimentation.

[0109] Figure 61 (which can also be referred to as Fig. 61) is a graph illustrating the behavior of output voltage by changing AC magnetic field and input voltage (applied to the ultrasound transducer) simultaneously at constant frequency for the MUDG5 device during experimentation work.

[0110] Figure 62 (which can also be referred to as Fig. 62) is a graph illustrating the measured impact of power output when rotating the MUDG5 device along the z-axis (in the x-y plane) measured during experimentation work.

[0111] Figure 63 (which can also be referred to as Fig. 63) is a schematic diagram of an exemplary embodiment of an apparatus for wireless energy harvesting that can utilize an embodiment of our MUDG device. Figure 64 (which can also be referred to as Fig. 64) is a schematic illustration of an experimental setup for evaluation of an embodiment of our apparatus and process for wireless energy harvesting utilizing an embodiment of our MUDG device.

[0112] Figure 65 (which can also be referred to as Fig. 65) is a schematic illustration of an exemplary embodiment of our apparatus for wireless energy harvesting utilizing an embodiment of our MUDG device.

[0113] Figure 66 (which can also be referred to as Fig. 66) is a table illustrating the dimensions of the MUDG devices evaluated in conducted testing and the properties in air medium.

[0114] Figure 67 (which can also be referred to as Fig. 67) is a table providing a summary of the properties of synthesized piezoelectric materials for evaluated MUDG devices.

[0115] Figure 68 (which can also be referred to as Fig. 68) is a table that illustrates the strain, piezomagnetic constant and optimum DC magnetic field strength of different MUDG devices with different number of magnetostrictive layers that were evaluated in testing discussed herein.

[0116] DETAILED DESCRIPTION

[0117] Referring to Figures 1, 42, and 43, an apparatus for wireless energy harvesting can include a magnetic field and acoustic wave induced dual generator (MADG). A MADG device can be configured to operate under a magnetic field individually, operate under acoustic waves individually, or operate simultaneously when exposed to magnetic field and acoustic waves such that the device can provide three different modes of operation (e.g. magnetic field only, acoustic wave only, or operation under both a magnetic field and ultrasound).

[0118] Some embodiments of our MADG device can be configured as a magnetic field and ultrasound induced dual generator (MUDG) device that can operate under a magnetic field individually, operate under ultrasound individually, or operate simultaneously when under magnetic field and ultrasound such that the device can provide three different modes of operation (e.g. magnetic field only, ultrasound only, or operation under both a magnetic field and ultrasound). In such embodiments, the MADG device can be configured to utilize ultrasound waves as the acoustic waves that the device is configured to utilize.

[0119] Embodiments of the MADG device can be configured to produce power from multiple sources of wireless energy (e.g. magnetic field exposure and exposure to ultrasound waves or other types of acoustic waves). The MADG device can be configured to utilize either wireless energy source for energy harvesting or can utilize both such sources simultaneously.

[0120] In some embodiments, the MADG device can be configured as a MUDG device configured to generate ultrahigh RMS power (e.g. an RMS power of -52.1 mW with power density of -597 mW / cm3in response to be exposed to -500 pT magnetic field and 675 mW / cm2ultrasound intensity). This type of power level is the highest reported value compared to all the prior devices with applied input under applicable FDA and IEEE safety limits. Results from our evaluation of embodiments of our MUDG devices further demonstrate that embodiments of our MADG device and embodiments of our MUDG device can overcome the limitations of traditional wireless power systems for human body application as well as remote positioning in other environments (e.g. remote positioning in locations within a building or within a facility, etc.) that can provide a new platform with ultra-high-power density, small size, and tolerance to angular misalignment (x-y plane).

[0121] Embodiments can be configured so that electronic devices can be deployed without having to significantly worry about the power source or a duration of charging of the electronic device, which can open a wide range of potential applications. For example, an embodiment can be utilized in a sensor that is configured to be deployed around a ship to measure the structural damage of the ship (e.g. sensors can be glued or affixed to the ship structure just like postage stamps on an envelope and power can be supplied to these sensors through a combination of magnetic and acoustic waves, etc.). As another example, an embodiment can be configured to be incorporated into a sensor or medical device that is to be implanted into the body of an animal and can have its power recharged via exposure to a combination of magnetic and acoustic waves (e.g. ultrasound waves, etc.).

[0122] As discussed herein, we also performed systematic studies including evaluation of possible ways to provide MUDG device optimization for certain applications, the powering of electronics, transcutaneous transmission, power transfer ex-vivo, and safety analysis to evaluate how embodiments of our MUDG device can be employed in different applications.

[0123] As shown in Figures 1 and 43, an embodiment of our MUDG device can be positioned to be exposed to magnetic energy (e.g. a magnetic field generated via a magnet and coil) as well as ultrasound energy (e.g. via ultrasound waves output from an ultrasound transducer). The MUDG device can be connected to an electrical circuit and / or battery or other type of electrical energy storage device for harvesting energy from the magnetic field and / or ultrasound waves for charging the battery or other electrical storage device. In some embodiments, a rectifier can be connected between the battery and the MUDG device to facilitate such charging.

[0124] Figures 2 and 43 illustrate an exemplary embodiment of a MUDG device 1. The MUDG device 1 can include a plurality of magnetostrictive layers, resin layers, and a piezoelectric layer 7. Each magnetostrictive layer can have an adjacent resin layer that is positioned so that a resin layer is between adjacent magnetostrictive layers. A resin layer can be comprised of a polymeric material and a magnetostrictive layer can be comprised of iron (Fe) (e.g. can be a Metglas material layer, or other type of material similar to a Metglas material layer that can be magnetostrictive, or magnetizable). In some embodiments, each magnetostrictive layer can also include silicon (Si) and boron (B) (e.g. include Fe, Si, and B). As yet another example, in some embodiments, the magnetostrictive layer(s) can include Nickel (Ni) or Fe, can include Fe, cobalt (Co), Si and B, can include Ni, B, Si and / or Co, can include gallium (Ga), terbium (Tb), dysprosium (Dy), Fe, Si, and / or B, or can include Ni, Si, Ga, Tb. Dy, and / or B. In some embodiments, each magnetostrictive layer can be comprised of Fe from 0 weight percent (wt%) to 100 wt%, Si from 0 wt% to 10 wt%, nickel from 0 wt% to 100 wt%, cobalt from 0 wt% to 5 wt%, molybdenum from 0 wt% to 8 wt%, niobium from 0 wt% to 7 wt%, B from 0 wt% to 5 wt%, chromium from 0 wt% to 5 wt%, manganese from 0 wt% to 2 wt% and / or copper from 0 wt% to 2 wt%.

[0125] There can be a number of different magnetostrictive layer in different embodiments. For example, there can be a first magnetostrictive layer, a second magnetostrictive layer, a third magnetostrictive layer, and a fourth magnetostrictive layer. A first resin layer can be positioned between the first and second magnetostrictive layers, a second resin layer can be positioned between the second and third magnetostrictive layers, a third resin layer can be positioned between the third and fourth magnetostrictive layers, and a fourth resin layer can be positioned between a first end or first side of a piezoelectric layer and the fourth magnetostrictive layer.

[0126] The piezoelectric layer 7 can be a piezoelectric disk. In some embodiments, the piezoelectric layer can include a MnCF and CuO co-doped Pb(In,Nb)O3-Pb(Mg,Nb)O3-PbTiO3 (PIN-PMN-PT) piezoelectric material. This material can be configured and / or shaped as disk, a rectangle, a square, a cube, or have another type of shape, for example. This MnCh and CuO codoped Pb(In,Nb)O3-Pb(Mg,Nb)O3-PbTiC>3 material can be referred to as a Cu-Mn-PIN-PMN-PT material herein as well.

[0127] The piezoelectric material coefficients can play a role in the generation of electrical voltage. Many different types of piezoelectric materials can be utilized in addition to Cu-Mn-PIN-PMN- PT for forming a piezoelectric layer 7. PZT, PMN-PT, PZN-PT, PMN-PZT, BT, and PT are examples of other types of materials that can be utilized for a piezoelectric layer 7. All these different exemplary materials can be fabricated in disk shape, square shape, or rectangular shape, for example.

[0128] In some embodiments, the piezoelectric layer 7 can be a single layer. In other embodiments, the piezoelectric layer 7 can include two or more layers or be a co-fired multilayer. Each piezoelectric layer has a top electrode layer and a bottom electrode layer which can be configured for collecting electrical charge(s).

[0129] The piezoelectric layer 7 can have a second end or second side opposite its first side or first end. In some embodiments that may utilize a single piezoelectric layer, this second side can be adjacent to a magnetostrictive layer of a plurality of such layers as well. For instance, there can be a fifth magnetostrictive layer, sixth magnetostrictive layer, seventh magnetostrictive layer, and eighth magnetostrictive layer positioned adjacent to the second end or second side of the piezoelectric layer. There can also be a resin layer between each magnetostrictive layer adjacent the second side or second end of the piezoelectric layer. For instance, a fifth resin layer can be positioned between the second side or second end of the piezoelectric layer and the fifth magnetostrictive layer, a sixth resin layer can be positioned between the fifth magnetostrictive layer and the sixth magnetostrictive layer, a seventh resin layer can be positioned between the sixth magnetostrictive layer and the seventh magnetostrictive layer, and an eight resin layer can be positioned between the seventh magnetostrictive layer and the eight magnetostrictive layer. Each distal end or distal side of the magnetostrictive layering can have a coating positioned thereon. For example, there can be a polydimethylsiloxane (PDMS) coating or a chlorinated poly(para-xylylene) polymer coating (e.g. parylene-C coating) positioned on the outermost magnetostrictive layer for each side of the MUDG device and / or coating the entire device (as may best be appreciated from Figure 42). The polymeric coating can be provided to help protect the MUDG device from water infiltration or liquid infiltration into the body of the device.

[0130] In embodiments that may utilize multiple piezoelectric layers 7, a first piezoelectric layer 7 can have a first side adjacent to a magnetostrictive layer or a plurality of such layers and a second piezoelectric layer can have a second side adjacent to a magnetostrictive layer or a plurality of such layers.

[0131] For embodiments that may utilize multiple piezoelectric layers 7, the additional piezoelectric layer(s) 7 can be positioned so that each piezoelectric layer 7 has at least one magnetostrictive layer between the piezoelectric layers. For instance, in some embodiments that may utilize two piezoelectric layers 7 (e.g. a magnetorestrictive- piezoelectric - magnetorestrictive-piezoelectric-magnetorestrictive layering arrangement), the second side of the first piezoelectric layer 7 can be adjacent at least one middle magnetostrictive layer and the first side of the second piezoelectric layer can be adjacent the at least one middle magnetorestrictive layer.

[0132] Other embodiments can utilize more than 2 piezoelectric layers 7 and more than one middle magnetostrictive layer. For example, the layering can be provided so that there is a formed device having a magneto-piezo-magneto-piezo-magneto-piezo- magneto layered structure, for instance. Additionally, magnetostrictive electrodes such as Ni can be added to further amplify the effect.

[0133] Silver paste or other suitable electrically conductive material paste (e.g. Pt paste, Au paste, Ni paste and / or Cu paste, etc.) can be positioned to help bond different layers of the MUDG device to each other as may best be seen in Figure 42. For example, the silver paste can be positioned to encapsulate the structure of piezoelectric layer(s) 7 and the magnetostrictive layer(s) and the resin layer(s) in some embodiments. In some embodiments, the silver paste can be positioned to connect the top electrode of a piezoelectric layer with magnetostrictive layer(s) and a bottom electrode of a piezoelectric layer with magnetostrictive layer(s). The silver paste can be spread along a certain area with resin that can make connectivity to make an electrode, for example.

[0134] Instead of silver paste, other suitable paste can be utilized. Examples of such paste can include platinum (Pt) paste, silver / palladium (Ag / Pd) paste, Au paste, Ni paste, Cu paste, or other suitable paste etc. that can be used instead of silver paste or in combination with silver paste.

[0135] The MUDG device 1 can be configured to have multiple different magnetostrictive layers and resin layers for each array of magnetostrictive layers and resin layers on opposite sides of the piezoelectric layer. For example, the MUDG device 1 can have a body having a first side 3 and a second side 5. The body can also include a piezoelectric layer 7, which can be positioned between the first and second sides 3 and 5 (e.g. be in a middle region or central region of a body of the MUDG device 1). The first side 3 of the MUDG device can include a plurality of magnetostrictive layers and resin layers. The second side 5 of the MUDG device can also include a plurality of magnetostrictive layers and resin layers. The piezoelectric layer 7 can be positioned between the plurality of magnetostrictive layers and resin layers positioned adjacent the first side 3 and the plurality of magnetostrictive layers and resin layers positioned adjacent the second side 5.

[0136] In some embodiments, the first side 3 of the MUDG device can include a plurality of magnetostrictive layers that can include two or more magnetostrictive layers and two or more resin layers. For instance, embodiments of the MUDG device 1 can have a first side 3 that has a first magnetostrictive layer, a second magnetostrictive layer, a third magnetostrictive layer, a fourth magnetostrictive layer, and a fifth magnetostrictive layer. As another example, the MUDG device 1 can have a first side that has a first magnetostrictive layer, a second magnetostrictive layer, and a third magnetostrictive layer, or has a first magnetostrictive layer, a second magnetostrictive layer, a third magnetostrictive layer, a fourth magnetostrictive layer, a fifth magnetostrictive layer, and a sixth magnetostrictive layer.

[0137] In such embodiments, the first magnetostrictive layer of the first side 3 can be considered an outermost magnetostrictive layer and another magnetostrictive layer that is closest to the piezoelectric layer 7 adjacent the first side 3 of the MUDG device can be considered an innermost magnetostrictive layer of the first side 3. There can also be a plurality of resin layers positioned so that there is a resin layer between adjacent magnetostrictive layers and a resin layer positioned between the innermost magnetostrictive layer of the first side 3 and the piezoelectric layer 7.

[0138] For instance, a first resin layer of the first side 3 can be positioned between the first and second magnetostrictive layers of the first side 3, a second resin layer can be positioned between the second and third magnetostrictive layers of the first side 3, and a third resin layer can be positioned between the third magnetostrictive layer and the piezoelectric layer 7 for some embodiments of the MUDG device 1 (e.g. the third magnetostrictive layer of the first side 3 can be considered the innermost magnetostrictive layer of the first side 3 and the first magnetostrictive layer of the first side 3 can be considered the outermost magnetostrictive layer for this embodiment).

[0139] As another example, a first resin layer of the first side 3 can be positioned between the first and second magnetostrictive layers of the first side 3, a second resin layer can be positioned between the second and third magnetostrictive layers of the first side 3, a third resin layer can be positioned between the third magnetostrictive layer and fourth magnetostrictive layer of the first side 3, and a fourth resin layer can be positioned between the fourth magnetostrictive layer of the first side 3 and the piezoelectric layer 7 for some embodiments of the MUDG device 1 (e.g. the fourth magnetostrictive layer of the first side 3 can be considered the innermost magnetostrictive layer of the first side 3 and the first magnetostrictive layer of the first side 3 can be considered the outermost magnetostrictive layer for this embodiment).

[0140] As yet another example, a first resin layer of the first side 3 can be positioned between first and second magnetostrictive layers of the first side 3, a second resin layer can be positioned between second and third magnetostrictive layers of the first side 3, a third resin layer can be positioned between third magnetostrictive layer and fourth magnetostrictive layer of the first side 3, a fourth resin layer can be positioned between the fourth magnetostrictive layer and the fifth magnetostrictive layer of the first side 3, and a fifth resin layer can be positioned between the fifth magnetostrictive layer and the piezoelectric layer 7 for some embodiments of the MUDG device 1 (e.g. the fifth magnetostrictive layer of the first side 3 can be considered the innermost magnetostrictive layer of the first side 3 and the first magnetostrictive layer of the first side 3 can be considered the outermost magnetostrictive layer for this embodiment).

[0141] As yet another example, a first resin layer of the first side 3 can be positioned between first and second magnetostrictive layers of the first side 3, a second resin layer can be positioned between second and third magnetostrictive layers of the first side 3, a third resin layer can be positioned between third magnetostrictive layer and fourth magnetostrictive layer of the first side 3, a fourth resin layer can be positioned between the fourth magnetostrictive layer and the fifth magnetostrictive layer of the first side 3, a fifth resin layer can be positioned between the fifth magnetostrictive layer and a sixth magnetostrictive layer of the first side 3, and a sixth resin layer can be positioned between the sixth magnetostrictive layer and the piezoelectric layer 7 for some embodiments of the MUDG device 1 (e.g. the sixth magnetostrictive layer of the first side 3 can be considered the innermost magnetostrictive layer of the first side 3 and the first magnetostrictive layer of the first side 3 can be considered the outermost magnetostrictive layer for this embodiment).

[0142] The second side 5 can have a similar arrangement of magnetostrictive layers and resin layers as the first side 3 or can alternatively have a different arrangement. Typically, it is contemplated that the second side 5 will have a similar arrangement of the magnetostrictive layers and resin layers as the first side 3. However, it is contemplated that some embodiments may utilize different arrangements for the different sides.

[0143] For instance, the second side 5 of the MUDG device can include a plurality of magnetostrictive layers that can include two or more magnetostrictive layers and two or more resin layers. For instance, embodiments of the MUDG device 1 can have a second side 5 that has a first magnetostrictive layer, a second magnetostrictive layer, a third magnetostrictive layer, a fourth magnetostrictive layer, and a fifth magnetostrictive layer. As another example, the MUDG device 1 can have a second side 5 that has a first magnetostrictive layer, a second magnetostrictive layer, and a third magnetostrictive layer, or has a first magnetostrictive layer, a second magnetostrictive layer, a third magnetostrictive layer, a fourth magnetostrictive layer, a fifth magnetostrictive layer, and a sixth magnetostrictive layer.

[0144] In such embodiments, the first magnetostrictive layer of the second side 5 can be considered an outermost magnetostrictive layer and another magnetostrictive layer that is closest to the piezoelectric layer 7 adjacent the second side 5 of the MUDG device can be considered an innermost magnetostrictive layer of the second side 5. There can also be a plurality of resin layers positioned so that there is a resin layer between adjacent magnetostrictive layers and a resin layer positioned between the innermost magnetostrictive layer of the second side 5 and the piezoelectric layer 7.

[0145] For instance, a first resin layer of the second side 5 can be positioned between the first and second magnetostrictive layers of the second side 5, a second resin layer can be positioned between the second and third magnetostrictive layers of the second side 5, and a third resin layer can be positioned between the third magnetostrictive layer and the piezoelectric layer 7 for some embodiments of the MUDG device 1 (e.g. the third magnetostrictive layer of the second side 5 can be considered the innermost magnetostrictive layer of the second side 5 and the first magnetostrictive layer of the second side 5 can be considered the outermost magnetostrictive layer for this embodiment).

[0146] As another example, a first resin layer of the second side 5 can be positioned between the first and second magnetostrictive layers of the second side 5, a second resin layer can be positioned between the second and third magnetostrictive layers of the second side 5, a third resin layer can be positioned between the third magnetostrictive layer and fourth magnetostrictive layer of the second side 5, and a fourth resin layer can be positioned between the fourth magnetostrictive layer of the second side 5 and the piezoelectric layer 7 for some embodiments of the MUDG device 1 (e.g. the fourth magnetostrictive layer of the second side 5 can be considered the innermost magnetostrictive layer of the second side 5 and the first magnetostrictive layer of the second side 5 can be considered as the outermost magnetostrictive layer for this embodiment).

[0147] As yet another example, a first resin layer of the second side 5 can be positioned between first and second magnetostrictive layers of the second side 5, a second resin layer can be positioned between second and third magnetostrictive layers of the second side 5, a third resin layer can be positioned between third magnetostrictive layer and fourth magnetostrictive layer of the second side 5, a fourth resin layer can be positioned between the fourth magnetostrictive layer and the fifth magnetostrictive layer of the second side 5, and a fifth resin layer can be positioned between the fifth magnetostrictive layer and the piezoelectric layer 7 for some embodiments of the MUDG device 1 (e.g. the fifth magnetostrictive layer of the second side 5 can be considered the innermost magnetostrictive layer of the first side 3 and the first magnetostrictive layer of the second side 5 can be considered the outermost magnetostrictive layer for this embodiment).

[0148] As yet another example, a first resin layer of the second side 5 can be positioned between first and second magnetostrictive layers of the second side 5, a second resin layer can be positioned between second and third magnetostrictive layers of the second side 5, a third resin layer can be positioned between third magnetostrictive layer and fourth magnetostrictive layer of the second side 5, a fourth resin layer can be positioned between the fourth magnetostrictive layer and the fifth magnetostrictive layer of the second side 5 , a fifth resin layer can be positioned between the fifth magnetostrictive layer and a sixth magnetostrictive layer of the second side 5, and a sixth resin layer can be positioned between the sixth magnetostrictive layer and the piezoelectric layer 7 for some embodiments of the MUDG device 1 (e.g. the sixth magnetostrictive layer of the second side 5 can be considered the innermost magnetostrictive layer of the second side 5 and the first magnetostrictive layer of the second side 5 can be considered the outermost magnetostrictive layer for this embodiment).

[0149] Embodiments of the MUDG device 1 can utilize lead free piezoelectric layers or a biopolymeric based piezoelectric layer. Utilization of these types of piezoelectric layers can be compatible with the human body and / or an animal body to facilitate implanted use of the device.

[0150] Embodiments of the MUDG device 1 can also utilize nanoparticles of magnetic material (e.g. magnetic powders that include nanoparticles of magnetic material). Such nanoparticles can be included in the different resin layers of the MUDG device 1, for example. The magnetic nanoparticles can be positioned to concentrate the magnetic flux that can be exposed to the MUDG device 1.

[0151] The electrodes, or electrode layers, of the MUDG device 1 can be magnetostrictive in some embodiments. For example, each electrode layer can be comprised of Ni paste.

[0152] In some embodiments, the MUDG device 1 can be sized on a nanoparticle scale (e.g. be a up to a few hundred nanometers in size, etc.). Such embodiments can be configured to be triggered using a magnetic field and ultrasound field that may be applied simultaneously for different types of biomedical applications. For example, such nanoparticles can be injected into a body or a region of the body for having the magnetic field and ultrasound field applied to that region to facilitate imaging or other type of medical application.

[0153] As may best be seen in Figure 42, wires or other conductor elements can be connected to the first and second sides 3 and 5 of the MUDG device 1. The wires or other conductor elements can be positioned to convey current and / or voltage generated from electrical energy harvesting to a battery or other type of electrical energy storage device. Figure 3 illustrates an example of an in-vivo positioning of the MUDG device 1 that can be included in an apparatus for wireless energy harvesting for use in different types of biomedical or animal related uses. The MUDG device 1 can be positioned to harvest energy from ultrasound and / or magnetic fields to generate voltage for transmitting to a battery or other electrical energy storage device of a biomedical device positioned in the body of an animal Al . The animal Al can be a pig or a human or other type of animal. The type of biomedical device can be a type of sensor or other type of medical device (e.g. pacemaker, blood glucose monitor, a type of implantable device, etc.).

[0154] Figure 65 illustrates another embodiment of the apparatus for wireless energy harvesting that can utilize an embodiment of our MUDG device 1. The MUDG device can be incorporated into a wireless and remotely positioned sensor (e.g. camera, microphone, motion tracking sensor) or other type of wireless device (e.g. alarm system, etc.) for charging the battery or electrical energy storage device of the remote device. The MUDG device can be configured to charge the battery or electrical energy storage device via wireless signals emitted to that remote region (e.g. WiFi internet signals from an access point) and / or ultrasound or other sound signals that may be emitted to the region periodically to charge the remote device’s battery via the MUDG device. This type of assembly can help avoid the need for running electrical wiring or other substantial changes to infrastructure so that installation of a device in a remote location is simplified and the device is easy to charge and maintain for a long period of time (e.g. many months or many years). Also, as discussed herein, the MUDG device can be incorporated so that sufficient charging can be provided quickly via application of two or more types of energy signals (e.g. sound emission and WiFi emission or sound emission and magnetic field emission) at levels safe for humans for relatively short periods of time.

[0155] EXAMPLES AND EXPERIMENTAL RESULTS

[0156] We fabricated different embodiments of our MUDG device 1 having a structure similar to what is discussed above and shown in Figure 2 for experimental evaluation of different embodiments of our MUDG device 1 and how it may be utilized in different embodiments or our apparatus for wireless energy harvesting and / or processes for wireless energy harvesting. The fabricated devices included a MUDG3 device, a MUDG4 device, a MUDG5 device, and a MUDG6 device. Metglas material was used for the magnetostrictive layers in these fabricated embodiments due to its low cost, lightweight, flexible nature and high saturation magnetostriction at low DC magnetic fields. However (and as discussed herein) other types of suitable material can also be utilized for the magnetostrictive layers in other embodiments (e.g. Ni, Terfenol-D, Galfenol, or ferrites, etc.).

[0157] The piezoelectric layer 7 used in these evaluated MUDG devices utilized a radial mode disk-shaped piezoelectric layer that had tolerance to angular misalignment and provided a higher surface area that is suitable for ultrasound conversion as well. Other shapes and structures for a piezoelectric layer 7 can be utilized in other embodiments of our MUDG device as well (e.g. square or rectangular shaped piezoelectric layers poled along their thickness direction for a square of rectangular shaped MUDG device, etc.).

[0158] Figure 66 is a table illustrating the dimensions of the MUDG devices evaluated in conducted testing and the properties in air medium.

[0159] Figure 67 is a table providing a summary of the properties of synthesized piezoelectric materials for evaluated MUDG devices.

[0160] Figure 68 is a table that illustrates the strain, piezomagnetic constant and optimum DC magnetic field strength of different MUDG devices with different numbers of magnetostrictive layers that were evaluated in testing discussed herein.

[0161] The Evaluated MUDG3 Device

[0162] A “MUDG3” device was an exemplary embodiment of our MADG device that was formed that used first and second sides 3 and 5 that each had three magnetostrictive layers and three resin layers. The MUDG3 device that was formed had a piezoelectric layer 7 between the first and second sides 3 and 5. The piezoelectric layer had a disk shape and was comprised of a MnCF and CuO co-doped Pb(In,Nb)O3-Pb(Mg,Nb)C>3-PbTiO3 (PIN-PMN-PT) piezoelectric material (which can also be referred to as a Cu-Mn-PIN-PMN-PT material).

[0163] The MUDG3 device included a first resin layer of the first side 3 positioned between first and second magnetostrictive layers of the first side 3, a second resin layer positioned between the second and third magnetostrictive layers of the first side 3, and a third resin layer of the first side 3 positioned between the third magnetostrictive layer and the piezoelectric layer 7. The MUDG3 device included a first resin layer of the second side 5 positioned between first and second magnetostrictive layers of the second side 5, a second resin layer positioned between the second and third magnetostrictive layers of the second side 5, and a third resin layer of the second side 5 positioned between the third magnetostrictive layer and the piezoelectric layer 7. Each resin layer was comprised of a polymeric material (e.g. epoxy) and each magnetostrictive layer was comprised of a Metglas material (e.g. comprised of Fe, Si, and B) and was a magnetizable material.

[0164] The Evaluated MUDG4 Device

[0165] A “MUDG4” device was an exemplary embodiment of our MADG device that was formed that used first and second sides 3 and 5 that each had four magnetostrictive layers and four resin layers. The MUDG4 device that was formed had a piezoelectric layer 7 between the first and second sides 3 and 5. The piezoelectric layer had a disk shape and was comprised of a MnO? and CuO co-doped Pb(In,Nb)O3-Pb(Mg,Nb)O3-PbTiO3 (PIN-PMN-PT) piezoelectric material (which can also be referred to as a Cu-Mn-PIN-PMN-PT material).

[0166] The MUDG4 device included a first resin layer of the first side 3 positioned between first and second magnetostrictive layers of the first side 3, a second resin layer positioned between the second and third magnetostrictive layers of the first side 3, a third resin layer positioned between the third and fourth magnetostrictive layers and a fourth resin layer of the first side 3 positioned between the fourth magnetostrictive layer and the piezoelectric layer 7. The MUDG4 device included a first resin layer of the second side 5 positioned between first and second magnetostrictive layers of the second side 5, a second resin layer positioned between the second and third magnetostrictive layers of the second side 5, a third resin layer positioned between the third and fourth magnetostrictive layers of the second side 5 and a fourth resin layer of the second side 5 positioned between the fourth magnetostrictive layer and the piezoelectric layer 7. Each resin layer was comprised of a polymeric material (e.g. epoxy) and each magnetostrictive layer was comprised of a Metglas material (e.g. comprised of Fe, Si, and B) and was a magnetizable material.

[0167] The Evaluated MUDG5 Device

[0168] A “MUDG5” device was an exemplary embodiment of our MADG device that was formed that used first and second sides 3 and 5 that each had five magnetostrictive layers and five resin layers. The MUDG5 device that was formed had a piezoelectric layer 7 between the first and second sides 3 and 5. The piezoelectric layer had a disk shape and was comprised of a MnCh and CuO co-doped Pb(In,Nb)O3-Pb(Mg,Nb)O3-PbTiO3 (PIN-PMN-PT) piezoelectric material (which can also be referred to as a Cu-Mn-PIN-PMN-PT material).

[0169] The MUDG5 device included a first resin layer of the first side 3 positioned between first and second magnetostrictive layers of the first side 3, a second resin layer positioned between the second and third magnetostrictive layers of the first side 3, a third resin layer positioned between the third and fourth magnetostrictive layers of the first side, a fourth resin layer positioned between the fourth and fifth magnetostrictive layers of the first side 3 and a fifth resin layer of the first side 3 positioned between the fifth magnetostrictive layer and the piezoelectric layer 7. The MUDG5 device included a first resin layer of the second side 5 positioned between first and second magnetostrictive layers of the second side 5, a second resin layer positioned between the second and third magnetostrictive layers of the second side 5, a third resin layer positioned between the third and fourth magnetostrictive layers of the second side 5, a fourth resin layer positioned between the fourth and fifth magnetostrictive layers of the second side 5, and a fifth resin layer of the second side 5 positioned between the fifth magnetostrictive layer and the piezoelectric layer 7. Each resin layer was comprised of a polymeric material (e.g. epoxy) and each magnetostrictive layer was comprised of a Metglas material (e.g. comprised of Fe, Si, and B) and was a magnetizable material.

[0170] The Evaluated MUDG6 Device

[0171] A “MUDG6” device was an exemplary embodiment of our MADG device that was formed that used first and second sides 3 and 5 that each had six magnetostrictive layers and six resin layers. The MUDG6 device that was formed had a piezoelectric layer 7 between the first and second sides 3 and 5. The piezoelectric layer had a disk shape and was comprised of a MnO? and CuO co-doped Pb(In,Nb)O3-Pb(Mg,Nb)O3-PbTiO3 (PIN-PMN-PT) piezoelectric material (which can also be referred to as a Cu-Mn-PIN-PMN-PT material).

[0172] The MUDG6 device included a first resin layer of the first side 3 positioned between first and second magnetostrictive layers of the first side 3, a second resin layer positioned between the second and third magnetostrictive layers of the first side 3, a third resin layer positioned between the third and fourth magnetostrictive layers of the first side 3, a fourth resin layer positioned between the fourth and fifth magnetostrictive layers of the first side 3, a fifth resin layer positioned between the fifth and sixth magnetostrictive layers of the first side 3 and a sixth resin layer of the first side 3 positioned between the sixth magnetostrictive layer and the piezoelectric layer 7. The MUDG6 device included a first resin layer of the second side 5 positioned between first and second magnetostrictive layers of the second side 5, a second resin layer positioned between the second and third magnetostrictive layers of the second side 5, a third resin layer positioned between the third and fourth magnetostrictive layers of the second side 5, a fourth resin layer positioned between the fourth and fifth magnetostrictive layers of the second side 5, a fifth resin layer positioned between the fifth and sixth magnetostrictive layers of the second side 5, and a sixth resin layer of the second side 5 positioned between the sixth magnetostrictive layer and the piezoelectric layer 7. Each resin layer was comprised of a polymeric material (e.g. epoxy) and each magnetostrictive layer was comprised of a Metglas material (e.g. comprised of Fe, Si, and B) and was a magnetizable material. In some embodiments, each resin layer can include nanoparticles of the magnetic material to concentrate the magnetic flux as well.

[0173] MAGNETIC FIELD HARVESTING EXPERIMENTS

[0174] A magnetic field was applied on to the MUDG devices (MUDG3, MUDG4, MUDG5, and MUDG6) along its length in the < 100) direction of the Metglas sheet and generated output power was measured along the thickness direction in air medium using an experimental setup as shown in Figure 4. The deformation in the piezoelectric layer resulted in the generation of electric charges from the MUDG devices through the direct piezoelectric effect. The amplitude of the ME coupling that is produced by the strain from the magnetostrictive layer is an important factor in determining the performance of the MUDG generators. The magnetic energy harvesting performance of the MUDG devices was investigated using a customized 3D-printed Helmholtz coil that generates an AC magnetic field (AC ag); and DC electromagnets used for DC magnetic field generation. Optimization of magnetostrictive layers for these particular embodiments of the evaluated MUDG devices was verified by measuring strain and piezomagnetic coefficient at a constant AC magnetic field and working frequency. For example, the magnetic energy harvesting performance of the MUDG devices was investigated using a customized Helmholtz coils that generates an AC magnetic field ( / / AC ) and electromagnets responsible for applying DC magnetic field. To confirm the optimum DC magnetic field, we repeatedly measured the strain value of different MUDG devices using strain sensor by changing DC magnetic field as can be appreciated from Figures 44-46.

[0175] The magnetoelectric voltage coefficient (CIME) was found to be maximized when a specific DC magnetic field is applied along with the AC magnetic field. At constant frequency,

[0176] MUDG devices that were evaluated were able to generate maximum UME at an optimum DC magnetic bias of~190 Oe, -240 Oe, -290 Oe, and -360 Oe for MUDG3, MUDG4, MUDG5, and

[0177] MUDG6, respectively (Figure 5). The magnetoelectric (ME) device coupling relationship for the

[0178] MUDG devices that were evaluated can be written as:

[0179] Where E is the electric field, D is the electric displacement, T is the mechanical stress, S is the mechanical strain and H is the magnetic field. The first part of the equation (i) is a non-magnetic factor and hence the modified equation can be written as:

[0180] The equation (ii) indicates that the MUDG response is correlated to the differential of the strain (X) and magnetic field values, i.e., directly related to the piezomagnetic property.

[0181] We found that the MUDG5 device exhibited the highest OIME value of -154 V / cm-Oe (Fig. 5). The combined effect of high strain and piezomagnetic coefficient (-0.122) resulted in the highest OCME for MUDG5 device (Figs. 44-45).

[0182] Fig. 6 shows the output peak voltage (Vp) as a function of working frequency of the MUDG devices and the maximum output voltage corresponded to a working frequency range of 252-264 kHz. MUDG5's lower frequency was attributed to a slightly different piezoelectric disk diameter (0.8 mm) compared to piezo disk (0.78 mm) used in MUDG4. The high voltage for MUDG4 is related to the high impedance of the MUDG4 device (ESI, Note S4, Fig. S7). For example, Fig. 44 shows that the strain values increased with increasing of DC magnetic field and saturated at higher DC magnetic field. The maximum strain value of 16.27 has been achieved for MUDG6 device because of the larger number of magnetostrictive layers. But maximum stain was not responsible for optimum DC magnetic field. To know the optimum DC magnetic bias, the piezomagnetic (PM) constant (Fig. 45) has been considered and calculated from DC field vs. strain curve as described in Fig. 45.

[0183] The impedance and frequency profiles of the evaluated MUDG devices under water showed a similar tendency (Figs. 47 and 48). The impedance of the evaluated MUDG devices decreased due to the water medium which is a general trend (Figs. 47-48). Under water, the resonance frequency also decreases for the evaluated MUDG devices compared with frequency measured in air medium.

[0184] The generated power was found to be highest for MUDG5 device compared to all the evaluated MUDG devices as discussed below. The calculated quality factor for MUDG5 is -290, which has a considerable impact on the link’s bandwidth, optimal loading, and importantly power transfer efficiency.

[0185] The quality factor (Q) can be obtained from voltage vs. frequency curve, as the ratio of measured maximum voltage (at the working frequency) to the half power bandwidth, as shown in Fig. 49 for MUDG5 device. The ^-factor with an increasing DC magnetic field is as shown Fig. 50. Fig. 51 shows the dependence of the optimum DC bias values for the different MUDG devices. Q increasing with the DC magnetic bias indicates that the fabricated devices are in good condition. Fig. 52 signifies the working frequency may also change with the changing of DC bias applied during energy harvesting measurement.

[0186] To better understand the evaluated MUDG devices’ output property under magnetic field, a 3D simulation based on the finite element method (FEM) was analyzed using COMSOL multiphysics software. The cylindrical model was built using the COMSOL multiphysics with the constituent Metglas magnetostrictive phase and PZT-4 piezoelectric layers — the diameter of the piezo discs and Metglas layers was kept at 9.9 mm. The piezoelectric layer with a thickness of 0.8 mm and the Metglas layer with a thickness of 0.115 mm (equivalent to 5 layers) were used for the simulation. The model was first constructed in 3D and then reduced to 2D-axisymmctric using the geometric reduction feature to reduce the computation time. The MUDG device was placed in the airspace of 100 mm diameter. Regarding material properties, inbuilt PZT-4 data was used for the piezoelectric layer and Metglas properties provided by the manufacturer were used.

[0187] For simulations to evaluate the effect of the magnetoelectric effect, the physics included in the model consisted of solid mechanics, magnetic fields, and electrostatics. A background field with 100 pT rms AC field and 250 Oe DC field was set as the magnetic field physics component. Magnetostriction and piezoelectric effect multiphysics were included. A mechanical damping factor of 0.005 was included for the magnetostrictive and piezoelectric layers. With stationary and frequency domain perturbation studies, the model was simulated. The frequency dependent output voltage and distribution of piezo potential within the MUDG5 is displayed (Figs. 7-8). The simulated output voltage and frequency dependent behavior was found to be similar to the experimental results for MUDG5 device in air medium. However, the experimentally observed voltage is slightly lower (~12 V) than the simulated result (~13 V), which could be attributed to the different piezo element and damping factor used in simulation.

[0188] The output power of the MUDG devices that were evaluated were measured using external load resistances under 100 pT AC magnetic field. The optimum load resistance was verified by measuring output voltage / frequency with the changing of frequency / load resistance. The output power was obtained by measuring root-mean-square (RMS) output voltage (Fnns) at different external load resistances (R\ ) (100 to 10 M.Q). The average rms power (Pnns) was calculated as follows:

[0189] Fig. 9 shows the generated / f-ms power from MUDG devices under 100 pT magnetic field at constant working frequency. The MUDG device achieves an average mis power of 0.66 mW across a load of 22 kf> at 254 kHz frequency. MUDGs was coated (6-8pm) with Parylene-C due its biocompatibility, bacterial resistance, chemical resistance, insulation, thickness control and importantly acoustic impedance matching (2.84 Mrayl) close to tissue (1.5 Mrayl). Although PDMS is more transcutaneous, it is difficult to control its thickness and there is high possibility to damage the coating near the shouldering area of electrical wires.

[0190] The thickness ratio can help indicate the power of the MUDG devices and it was 0.15 for MUDG5 (Fig. 53). The thickness ratio (tm / tp) is defined as the ratio of thickness of magnetic layer (tm) with thickness of the piezoelectric material (tp). The leakage and safety issue of the devices under water / tissue is managed by using the Parylene-C coating over the device. The reason behind using Parylene-C coating (6-8 pm) is related to its corrosion and chemical resistance with biocompatibility. This protects the devices from the water and probable toxic effect of chemicals. The performance of the Parylene-C coated (6-8pm) MUDG5 gives similar output power (0.65 mW) as compared to devices without Parylene-C coating (0.66 mW) as shown in Fig. 54. But PDMS encapsulated MUDG5 gives lower output power (0.42 mW) compared to Parylene-C coated MUDG5 device (Fig. 54).

[0191] The decrease in performance can be attributed to the difference in thickness between the PDMS coating which is around 500pm, and the Parylene-C coating which was only 6-8pm thick. Maintaining the exact thickness of PDMS on the device was challenging as it can be difficult to control the edges of the device during the hand or spin coating process. Conversely, Parylene-C coating allowed for more precise thickness control in the conducted testing and experimentation work.

[0192] The individual magneto electric output performance of the MUDG devices were also checked in water using 3D printed small water tank that fit in between the Helmholtz coils and DC electromagnets. To evaluate the output performance of the MUDG devices under magnetic field and ultrasound, we immersed the MUDG3, MUDG5, MUDG5, and MUDG6 devices in water as illustrated in Figs. 55 and 58. Water was chosen as the medium for this testing because it is suitable for both magnetic and ultrasound energy, and it has a similar acoustic impedance as that of tissue. To harvest magnetic energy under water, we developed a system (Fig. 55) with a small water tank that fits between Helmholtz coils and DC electromagnets. The MUDG devices were coated with Parylene-C coating to protect them from the water and placed in the water tank with the bottom part of the device flat against the tank. To allow the wires to exit the water tank, we created two small holes in the container, which we sealed with hot glue to prevent water leakage. We then checked for any leaks using water, as shown in Fig. 55.

[0193] The measured working frequency of MUDG devices decreases up to -2-4 kHz underwater as compared to in-air operation (Fig. 10). The lower output voltage for MUDG devices is attributed to the lower impedance in water as compared to air (Figs.47-48). The power output in water (-0.65 mW at 2.5 kQ) was similar to air (-0.66 mW at 22 kQ) with 1 .5% reduction (Fig. 11). The output voltage was linearly proportional to the AC magnetic field, and it increased consistently at a constant working frequency (Fig. 56). This suggests a strong potential for achieving high power at high magnetic fields while operating below safety level e.g. 500pT AC magnetic field. The MUDG5 device was able to generate high level of power magnitude ~15.7mW at 500p.T and 250 kHz frequency. The MUDG5 device demonstrated -4 times the output power of a commercial PZT disk that is 1 mm thick (Fig. 57), which can be attributed to the superior piezoelectric properties of Cu-Mn-PIN-PMN-PT ceramics, including a high-quality factor, good piezoelectric coefficient, and low loss factor. We found that the MUDG5 device was able to significantly outperform other devices reported in the literature in terms of power generation.

[0194] ULTRASOUND HARVESTING EXPERIMENTS

[0195] To evaluate the output performance of the MUDG devices (MUDG3, MUDG4, MUDG5, and MUDG6), they were subjected to ultrasound pressure using a commercial transducer and output was measured in water to mimic the soft tissue at 5 mm and 15 mm distance. Fig. 13 illustrates the experimental setup that was utilized. During the measurements, both the transducer and the MUDG devices were immersed in water to realize the matching of the acoustic impedance which is similar to that of the tissue because the air has very high acoustic impedance which can drastically reduce power transfer efficiency. To find the impedance profile of commercial ultrasound transducer used as a transmitter in our measurements, the S-parameter measurements were conducted using a network analyzer. The impedance profile of transducer and input power at different driving voltage in the frequency range of 225 - 265 kHz was also determined for measurement and evaluation purposes.

[0196] The water utilized in the testing was selected as a water / tissue medium for measuring ultrasound performance due to their similar acoustic impedance values (1.5 / 1.7 Mrayl), unlike air (0.0004 Mrayl) which has a much higher value, causing a significant reduction in power transfer efficiency.

[0197] Burst mode signal was used to isolate electrical interference and to minimize reflections during the measurements (Fig. 14). A custom designed 3D printed holder was used to hold the MUDGs / transducers and prevent any misalignment. Despite the application of sound pressure on top of the devices, the MUDG devices were capable of vibrating independently in the radial direction at the working frequency under ultrasound intense pressure. The ultrasound transducer was driven under 45Vp-p (where Vp-p is peak to peak voltage) applied input voltage. The MUDG devices, powered by the ultrasound energy, were evaluated by measuring their output signals across a broad frequency range of 220-260 kHz (Fig. 15). The MUDG devices exhibit their maximum output voltage within the frequency range of -237-240 kHz, owing to the high input power produced from the transducer in the similar frequency range of -237-240 kHz.

[0198] The MUDG3 device produced a higher voltage output at 5 mm distance from the transducer compared to other MUDG devices when subjected to under similar -150 mW / cm2ultrasound intensity. This can be attributed to its smaller number of magnetostrictive layers and lower attenuation, and thus higher ultrasound pressure experienced by MUDG3. The performance at resonance frequency of the MUDG devices has been verified by adjusting similar ultrasound intensity level by changing electrical power applied to the transducer, discussed later in dual energy harvesting section. To assess the impact of ultrasound-induced piezoelectric effect, the COMSOL simulations encompassed solid mechanics, transient pressure acoustics, and electrostatics. For this simulation, the airspace was changed to water, and a uniform background pressure field with 10 kPa was applied and the pressure calculated.

[0199] The simulation incorporated both acoustic-structure boundary and piezoelectric effect and a 0.008 mechanical damping coefficient was added for magnetostrictive and piezoelectric layers. With frequency domain studies, the model was simulated and the results show frequency dependent output voltage trend were similar to the experimental data (Figs. 16-17). As expected, the simulated frequency of 252 kHz is closer to the resonance frequency of 250kHz for the MUDG5 device and the output voltage is well matched at 250 kHz frequency under similar ultrasound intensity. The RMS output power of the MUDG device was measured at constant ultrasound intensity and frequency across external load resistors. Optimal power of ~5 mW at 5000 load was obtained for MUDG3 at 5mm distance under 150 mW / cnr ultrasound intensity (Fig. 18). MUDG5 can generate output power of ~ 2.63 mW across 2500 load at 238kHz working frequency. Larger number of magnetostrictive layers result in output power due to greater pressure attenuation and constraints on ultrasound energy transfer due to reduced piezoelectric vibration. A linear relationship exists between the input and output voltage of MUDG devices.

[0200] The applied input voltage had a linear relationship with output voltage of MUDG devices at constant working frequency, facilitating tunable property of the device, which is shown in the results of Fig. 59 (illustrating MUDG3 results at 237kHz) and Fig. 60 (illustrating MUDG5 results at 250kHz).

[0201] The output voltage of MUDGs is significantly impacted by the acoustic pressure and acoustic beam area of the transducer. The focal point of a thickness-dependent transducer, which is the beam's minimum width, can be calculated using the following equation:31 where Dois diameter of the transducer and v is the sound velocity in the medium and f is the working frequency. The measured approximate focal length of the transducer is ~5mm and assuming negligible sound loss in the medium, the maximum value of intensity occurs at the focus point.

[0202] The beam area (30 mm2) is half of the transducer diameter (i.e., Do / 2) used for power generation under ultrasound but considered whole device area for power density calculation. An ex-vivo tissue experiment was conducted to confirm the power generation ability of the MUDG devices (Fig. 19). The tissue power absorption is heavily dependent on the acoustic frequency and penetration depth, as follows:32 where a0is the frequency-dependent acoustic absorption coefficient, f is working frequency and d is the penetration depth. Good acoustic matching of water and tissue with ultrasound, decreases the power loss (~ 0.2%) of the MUDG device.33MUDG3 and MUDG5 devices were able to generate -23.1 mW and 12.2 mW maximum power under 675 mW / cm2intensity at 237 kHz and 238 kHz frequency, respectively (Fig. 20). The calculated power transfer efficiency of -2.1% was achieved for MUDG3 device. Fig. 21 shows the ability to generate power of -8.28 mW and 5.09 mW at 15 mm distance, signifying the power transfer capability of the MUDG3 and MUDG5 devices under ultrasound effect.

[0203] MAGNETIC FIELD AND ULTRASOUND BASED SIMULTANEOUS ENERGY HARVESTING EXPERIMENTS

[0204] We also conducted testing and experimentation on the MUDG devices (MUDG3, MUDG4, MUDG5, and MUDG6) to evaluate their dual energy harvesting capability under magnetic field and ultrasound, cither individually or concurrently. A continuous sinusoidal mode with infinite cycles was utilized in the conducted evaluations. The experimental setups for measuring dual energy harvesting of MUDG devices are demonstrated in Fig. 22, Fig. 55, and Fig. 58. The measurement setup shown in Figs. 22, 55 and 58 were used to harvest magnetic and ultrasound energy at the same time using a single MUDG device. The MUDG devices were placed inside the water tank in such a way that the bottom part of the device is flat as shown in Fig. 55. To get the wires outside of the water tank for the setups of Figs. 22, 55, and 58, we made small holes in the container as needed. To protect water leakage, hot glue was used to seal the holes. We used a 3D printed holder for the MUDG device to help avoid any misalignment during the measurements.

[0205] The schematic illustration of dual energy harvesting in a water medium, where ultrasound is applied perpendicular to the magnetic field, is demonstrated in Fig. 23. Water was employed as the medium to measure the performance of dual energy harvesting since it has no impact on magnetic fields and has acoustic impedance similar to that of human tissue, particularly for ultrasound.

[0206] The magnetoelectric output bandwidth for MUDG devices is lower than that of ultrasound, and below 244 kHz, they do not elicit a response, as shown in Fig. 19. Hence, resonance frequency related to MUDG devices used for magnetoelectric effect was selected such as 250 kHz for MUDG5 and ultrasound intensity was adjusted by changing the electrical power applied to the transducer. Initially, the output voltage of the MUDG5 device was examined to comprehend the combined effect of magnetic field and ultrasound intensity. Under 200 pT magnetic field, MUDG5 produced an output voltage (Vp) of -7.29 V, and it generated -7.14 V under 137 mW / cm2ultrasound intensity (Fig. 24). Simultaneous measurement confirms the additive output voltage, i.e. -14.35 V, generated from MUDG5 device under 200 pT magnetic field and 137 mW / cm2ultrasound intensity. MUDG5 exhibits output power of -2.65 mW under 200 pT magnetic field (Fig. 25), and produces best output power of -5 mW under 137 mW / cm2ultrasound intensity (Fig. 26). Fig. 27 confirms the addition of output power of MUDGs under simultaneous magnetic field and ultrasound intensity at similar measurement condition. The MUDG5 device shows the maximum output power of -9.1 mW across 2.5 k load under dual stimulation of magnetic field and ultrasound (Fig. 26). Similar voltage from both stimulations resulted in 4X higher power as compared to individual stimulation. The working mechanism of MUDG devices can be explained in term of mechanical to electrical transduction from piezoelectric material. However, for the magnetoelectric conversion, the steps include magnetic field to mechanical excitation to generation of electrical energy. In dual stimulation condition, electrical potential was combined from the excitation of piezoelectric material (mechanical to electrical conversion).

[0207] Linear relationships existed between input voltage or AC magnetic field and output voltage under both ultrasound and magnetoelectric measurements. This is observed for the MUDG5 device, even when both AC magnetic field and applied input voltage to the ultrasound transducer are altered. The relationship between the input voltage (Vp-p) and output voltage (Vp-p) of MUDG5 at constant AC magnetic field (lOOpT) during ultrasound measurement is shown in Fig. 59. The relationship between the AC magnetic field and output voltage (Vp-p) ofMUDG5 at constant input voltage (90Vp-p) applied to the ultrasound transducer is shown in Fig. 60. The behavior of output voltage (Vp-p) by changing AC magnetic field and input voltage (applied to the ultrasound transducer) simultaneously at constant frequency is shown in Fig. 61.

[0208] Similarly at constant input voltage (90Vp-p applied to a commercial US transducer), with the increase of AC magnetic field the output voltage increases linearly at constant frequency of 250kHz (Fig. 59). The generated voltage from the MUDG5 device also has linear relationship with the simultaneous change of AC magnetic field and input voltage applied to the ultrasound transducer at constant frequency (Fig. 59).

[0209] This can allow for the customization of target output power depending on implantable condition and application areas. The MUDG5 device has individual power generation ability of -15.7 and -12.56 mW under 500 pT magnetic field and 675 mW / cnf ultrasound intensity (Figs. 28-29). However, simultaneous stimulation produces output power of -52.1 mW, which is 3x and 4x greater than individual magnetoelectric and ultrasound induced energy harvesting. MUDG5 has highest power generation ability under dual energy input i.e. at 500pT magnetic field and 675 mW / cm2ultrasound intensity (Fig. 30).

[0210] To verify the safety limit of generated power by commercial ultrasound transducer used as a transmitter in our measurements, we immersed it in a water tank located in front of a hydrophone at 5 mm distance, which generated the maximum peak pressure in all measurements. Ultrasound acoustic intensity measurement for different operation frequency and different input power has been done using the calibrated HGL0085 hydrophone (Onda Corp., Sunnyvale, CA) connected to a digital oscilloscope (with 50 termination) via the Onda AG-2010 preamplifier providing around 20 dB voltage gain.

[0211] The ultrasound intensity of the transducer was measured using calibrated hydrophone at working frequencies using the following equation:

[0212] Where Vppis the received peak-to-peak voltage across hydrophone, M(f) is the hydrophone’s sensitivity (V / Pa) for a given frequency based on calibrated data sheet and Z is the acoustic impedance of the water medium.

[0213] The calculated acoustic intensity of MUDG5 device obtained based on different input voltages applied to the ultrasound transducer at the same frequency during testing was determined. Table 1 below provides the results of these calculations (on next page).

[0214] Table 1; determined MUDG5 device acoustic intensity parameters

[0215] The combined power of -52.1 mW that was harvested is indeed the summation of the voltages which is close to (V15.7 + V12.5) = 56.3 mW'. The 8% power loss signifies marginal mismatch of the phases of sign voltage curves during simultaneous measuring condition (Fig. 24 inset). Despite promising power from individual stimulation, the combined output power under dual stimulation consistently achieves higher power density. The MUDG5’s performance has been verified and remains unchanged with the rotation of the device in the x-y plane, regardless of the presence of magnetic field or ultrasound. The excellent power transfer efficiency of -1.8% reached at maximum input power transfer condition, which was calculated based on the following equation:

[0216] Assuming larger beam area of the transducer which has similar area as that of the MUDG device, it is expected that the MUDG5 device would be capable of generating >100 mW power with >1.2 W / cm3power density at 500 pT magnetic field and 675 mW / cm2ultrasound intensity. Further, MUDG has great advantages of tolerance to misalignment and no effect on individual (ME or US) as well as dual (ME+US) power performance by rotation of the device along the z- axis (in x-y plane) (Fig. 62). However, it should be noted that rectangular-based devices face limitations as they cannot simultaneously exploit both advantages. Hence, the results demonstrated that MUDG devices can overcome the limitations of conventional wireless power systems for variety of applications including medical, loT and structural health monitoring, offering a new platform with ultra-high-power capability. POWER DENSITY EXPERIMENTS

[0217] Power density of MUDG devices were evaluated to better appreciate the possible practical applications embodiments of our apparatus and process that may utilize one or more embodiments of our MUDG devices can have. The conducted testing and evaluation verified at different input magnetic field / ultrasound intensity (Fig. 31). At lower magnetic field (100 pT) and ultrasound intensity (137 mW / cm2), the MUDG3 showed higher power density due to the predominance of ultrasound over the magnetoelectric effect in comparison to the MUDG5 (Fig. 31). However, MUDG5 can harvest highest power density of -596 mW / cm2under simultaneous power transfer condition when operating below human safety limit. To the best of our knowledge, the MUDG5 device exhibits the highest power density as compared to previously reported devices that employ magnetoelectric, ultrasound, or piezoelectric / triboelectric nanogenerator technologies under comparable measurement conditions.

[0218] To demonstrate the practical utility of the MUDG5 device, capacitors, supercapacitors, and batteries were charged by connecting it to a full bridge rectifier to convert the AC to DC electrical signal. The MUDG5 device was capable of rapidly charging capacitors under different conditions.

[0219] The detailed information on the battery charging circuit used in these evaluations is shown in Fig. 63. We used Linear Technologies LTC3588-1 energy harvesting integrated circuit (IC) along with its application circuit as provided by the manufacturer in the data sheet. The capacitor that needed to be charged, was placed at CSTORAGE in Fig. 63 and did not include the diode, the resistor, and the cell. To charge the different batteries with different capacities (1 mAh, 3 mAh, 5 mAh, 11 mAh, and 33 mAh), we used the circuit shown in Fig. 63. The charge limiting resistor in the circuit was used as per the cell manufacturer’s recommendations.

[0220] Table 2 below is provided that illustrates various charging capabilities that were determined from the conducted evaluation work (on next page).

[0221] Table 2; charging capabilities of MUDG5 device

[0222] For example, when subjected to a lOOpT magnetic field, the MUDG5 device could charge a 1 mF capacitor to 5.6V within 1 minute, a 4.4 mF capacitor to 5.5V within 4 minutes, and a 10 mF capacitor to 5.0V within 6.5 minutes (Fig. 32). When exposed to a higher magnetic field of 300pT, the device can charge a 10 mF capacitor to 9.76V in 6.36 minutes.

[0223] Energy storage (Estored) ability of the capacitors is calculated as:

[0224] Estored = 1 CV2nr2(viii) where C is the capacitance and V is the charging voltage on the capacitor at a definite time ( / ). MUDG5 is capable of storing high energy up to 15.68, 66.55 and 125 mJ for ImF, 4.4mF and 10 mF capacitors within a timeframe (1, 4 and 6.5 mins) under 100 pT magnetic field strength. For a lOmF capacitor under a 300 pT magnetic field strength, MUDG5 can store -476.29 mJ of energy. The average charging storage power (Pa) that is harvested can be calculated as:34

[0225] Pa = (CV2X 1 / t) (ix) where t is the period over which the power is calculated. Based on these measurements, the electrical power harvested by MUDG5 device for 4.4 mF and 10 mF capacitors were 0.264 mW and 1 .67 mW in 4.2 minutes, which are larger than previously reported results based on ultrasound energy harvester.

[0226] Hence, the MUDG5 device was able to charge fast, making it relevant for wireless loT's brief timeframes. The MUDG5 device could charge a IF supercapacitor to 3.7 V within 48 minutes at 300 pT magnetic field and 137 mW / cm2ultrasound intensity. In comparison, previously reported magnetoelectric device was found to take 275 minutes to charge 3.7 V under similar measurement conditions (Fig. 33). The MUDG5 device recharged a commercial Li-ion battery with 1-mA-hour capacity up to 3.06V within 36 minutes at 100 itT magnetic field and 137 mW / cm2ultrasound intensity, with an average charging rate of 1.67 mC / s (Fig. 34).

[0227] In general, the daily power consumption of a commercial pacemaker model KSR701 is around 289 pA hour. Thus, the MUDG5 device was found to be a safe and efficient option for wirelessly charging pacemaker batteries, neurostimulators, and other IMDs at a faster rate. Recharging at a faster rate is achievable with higher voltage, although commercial LTC circuits have a maximum limit of input voltage of 25V. Using dual stimulation, the device is capable of charging high-capacity Li-ion batteries such as 11 mAh and 33mAh to 3.1V in less than an hour, whether a transformer is used or not (Fig. 35).

[0228] Under dual energy harvesting techniques, the MUDG5 device is capable of powering multiple light-emitting diodes (Fig. 36). Therefore, the MUDG5 device has the capability to recharge Li-ion batteries at a faster rate, making it a promising option for wireless power transfer.

[0229] EX VIVO EXPERIMENTS

[0230] Ex-vivo studies using porcine tissue were also carried out to validate the implantability of MUDG5 device as demonstrated for dual energy harvesting under 5mm and 15 mm tissue. Figure 64 illustrates the experimental setup used for this testing. To measure the output power, the MUDG5 device was placed inside the porcine tissue and all the setup excluding electromagnet was placed under water. The reason to put the coils inside the water was to release the weight of tissue that may be possible to restrict certain amount of vibration of the MUDG under weight. To check the performance of the MUDG5 device we did ex-vivo experiment under porcine tissue with the thickness of 5 mm and 15 mm.

[0231] Typically, tissue that is 5 mm and 15 mm in thickness is considered appropriate implants for wireless energy transfer. The MUDG5 device was able to generate a high output power of -52.17 mW in porcine tissue under 500 pT magnetic field and 675 mW / cm2ultrasound intensity (Fig. 37). The output power of the MUDG5 device drops to 22mW at 15mm thickness in porcine tissue, primarily due to the device's lower ultrasound pressure and increased damping of tissue that restricts its vibration (Fig. 38). But if transducer is moving in lateral direction from 5 mm to 15 mm the energy harvesting performance of MUDG5 is vanished due to misalignment between the transducer and MUDG5.

[0232] The MUDG5 device can recharge the ImAh Li-ion battery up to 3.11 V within 35 mins with 1.78 times faster rate in tissue compared to water (3.06V within 36 mins) (Fig. 39). The faster charging rate in tissue medium attributed to the more concentrating magnetic field strength compared to that in water medium.

[0233] The MUDG5 device successfully recharged different batteries with 3 mAh, 5 mAh, 11 mAh, and 33 mAh capacity under 5mm thick porcine tissue (Figs. 39-41). It is believed that the performance of the MUDG5 device may be affected under ultrasound due to increased acoustic impedance, attenuation, reflection, and absorption in different tissue interfaces such as fat and muscle. However, the device's performance may be compensated under simultaneous measurement conditions through the induced magnetic field effect. The device had enough stability and durability without losing marginal performances after several hours of (160h) measurements in water / tissue medium in different measurement conditions (Fig. 41).

[0234] The possible capacitive behavior of Cu wire / insulator / water layers has been removed using Al foils (aluminum foils) placed into the water near the Helmholtz coils and connected to the ground with the oscilloscope (Fig. 64).

[0235] The maximum power obtained from MUDG5 device and recharging of different batteries was done under human safety limit. Hence, simultaneous utilization of magnetic field and ultrasound for dual energy harvesting presents a distinctive prospect to rapidly recharge batteries. This demonstrates the potential of the MUDG5 device to wirelessly power IMDs such as pacemakers, insulin pumps, neurostimulators, etc. It also shows embodiments of our MUDG device can facilitate integration for providing power sources for loT sensors and structural health monitoring sensors as well as other devices. SAFETY ISSUE AND OPTIMIZATION EXPERIMENTS

[0236] We also performed testing to consider and evaluate the safety limit for AC and DC magnetic field strength which are in the range of <550 pT and <1670 Oe according to the IEEE standard. The conducted testing shows that the individual as well as combined use of ultrasound and magnetic fields for energy harvesting via one or more MUDG devices should not have any harmful effect under 500 pT magnetic field.

[0237] Under ultrasound energy, some side-effects may occur during the propagation of mechanical waves through organisms, i.e., mechanical, thermal, and other possible effects. This may result in damage to tissue, abnormal cell migration, membrane dysfunction and altered gene expression.

[0238] The possibility to reduce the internal resistance of the devices under high-frequency excitation can increase the power and reduce mechanical damage. As recommended by FDA, the safety limit of the ultrasound spatial peak temporal average (SPTA) intensity is 720 mW / cm2for ultrasound diagnostic systems such as peripheral vessel, cardiac, fetal imaging, pediatric, intraoperative, and cephalic, according to as Track 3 new set of guidelines in 1992.

[0239] The measured ultrasound intensity for MUDG5 device is 675 mW / cm2, which is below the safety threshold and hence no harmful effect would be expected to occur under applied ultrasound intensity.

[0240] The mechanical index (MI) is a standard parameter to detect the mechanical damage that can happen due the thermal / mechanical effects coming from the side-effects during the propagation of ultrasound waves through organisms. The calculated MI for the MUDG5 device is 1.4, which is well within the FDA approved safety limit of 1.9 for general ultrasound diagnostic systems. The MI is calculated using the expression:

[0241] . . . Pni / lMHz , .

[0242] Ml - X - (x) 7 IMPav 7where f is the center frequency in MHz and Pnis the peak negative pressure of ultrasound in MPa. The compatibility issue of the fabricated devices is necessary for IMDs. Although the devices are not truly biocompatible, but biocompatible Parylene C encapsulation or other type of coating can be utilized to protect the body from biochemical reactions. Parylene C is an FDA approved polymer suitable for encapsulation of implantable medical devices (IMDs) because of the several factors (e.g. biocompatibility, bacterial resistance, chemical resistance, long shelf life, insulation and importantly acoustic impedance close to tissue). All the above properties of Parylene-C can reduce any possible toxic effect and even any leaching of particles from piezoelectric material during long time applications for embodiments of the MUDG device. Other coatings for encapsulation may also be used for different applications as well.

[0243] We believe one can enhance the ultrasound energy harvesting performance by introducing matching impedance among the different layers of the device which can be calculated using the following equation: where ZM is the matching impedance layer, and Z 1 and Z2 are the acoustic impedance layers of the 1 and 2 materials, respectively.

[0244] CELL ADHESION AND CYTOTOXICITY EXPERIMENTS

[0245] We also conducted experiments using Parylene-C-coated samples to evaluate their cytotoxicity through live / dead cell staining and cell viability using MTT assays (e.g. 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assays). Subsequently, we examined Huh7 cell adhesion on various samples, including a control sample coated with Poly-L-Lysine, Parylene-C coated samples both before and after exposure to oxygen plasma treatment for 1 and 5 minutes, over a 24-hour period. In our efforts to promote improved cell adhesion, we applied oxygen plasma treatment to the Parylene-C-coated surface for 1 and 5 minutes to enhance the hydrophilic properties of the Parylene-C surface. The results of our experiments revealed that cells adhered to the control sample, and to a slightly lesser extent on the Parylene-C coated samples. However, the oxygen plasma-treated samples (1 minute) exhibited an increase in cell adhesion, displaying a uniform distribution likely due to the favorable surface roughness and hydrophilic properties. Fluorescence images we obtained from the testing demonstrated that the control samples that lacked Parylene-C coating allowed cells to grow well on the surface with a uniform distribution and limited cell death. The live / dead staining results of our experimentation indicated that the number of live cells on the oxygen plasma-treated Parylene-C coated samples (1 and 5 minutes) closely resembled that of the controls. Additionally, there were very few observed dead cells, suggesting minimal cytotoxicity.

[0246] The MTT assay results we obtained indicate that Parylene-C coated samples (coverslips / Metglas / Device) exhibited cell viability in the range of -85-90%, which suggest limited toxicity. The oxygen plasma treated Parylene-C coated samples also exhibited limited toxicity. All these findings from our conducted experimentation showed that Parylene-C-coated samples are non-cytotoxic, promote good cell viability and indicate that the Parylene-C-coated MUDG devices have great potential for biomedical implant uses (e.g. utilization for biomedical implant devices, etc.).

[0247] Our conducted testing demonstrated embodiments of our process and apparatus that can utilize at least one embodiment of our MUDG device can provide high-power small-scale energy harvesting device which can harvest ultrasound and magnetic field simultaneously. Wireless signal actuation / transmission chips can be integrated using an embodiment of our apparatus for wireless energy harvesting to utilize a process for wireless energy harvesting for diverse uses and functions for IMDs for healthcare / motion monitoring and data communication as well as for other applications.

[0248] Embodiments of our apparatus, MUDG device, and process can be configured to convert acoustic / magnetic energy into electricity. Some embodiments can provide this type of functionality via a milli scale energy harvesting device structure. The capability for wireless power transfer through water and animal tissue media was successfully demonstrated via numerous testing as discussed above.

[0249] Following FDA and IEEE regulations, testing showed that embodiments of our apparatus and process can be utilized to generate a stable high output power (e.g. power of -52.1 mW, etc.) and allow ex-vivo harvesting under animal tissue within a human safety limit considering magnetic field and ultrasound intensity.

[0250] Testing also demonstrated that embodiments can be configured to generate power on the order of milliwatts, which can enable charging of capacitors, supercapacitor, and recharging of batteries at relatively fast rates (e.g. recharging a 1 mAh capacity Li-ion battery at a rate of - 1.67 mC / s in animal tissue within 30 mins). The conducted testing and experimentation shows that embodiments of our apparatus and process can power IMDs such as a pacemaker, an implantable cardioverter, insulin pumps, glucose monitors, etc.

[0251] Embodiments can be adapted to facilitate integration of acoustic components, high- performance piezoactive elements, and wireless information transmission and actuation chips to provide efficient, safe, controllable, and communicable wireless systems that can provide energy harvesting via electromagnetic fields and acoustic energy (e.g. sound waves, acoustic waves, etc.) that can be emitted from an acoustic wave emission device (e.g. a speaker or acoustic wave transducer).

[0252] While certain present preferred exemplary embodiments of apparatuses and processes for wireless energy harvesting, exemplary embodiments of our MUDG devices and embodiments of methods for making and using the same have been shown and described above, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

What is claimed is:

1. An apparatus for wireless energy harvesting comprising: at least one magnetic field and acoustic wave induced dual generator (MADG) device configured to generate voltage and / or current in response to exposure to a magnetic field and acoustic waves.

2. The apparatus of claim 1, wherein the acoustic waves are ultrasound waves.

3. The apparatus of claim 2, wherein the magnetic field has an alternating current (AC) magnetic field strength that is less than or equal to 15 Oe.

4. The apparatus of claim 2, wherein the magnetic field is a direct current (DC) magnetic field having a strength that is less than or equal to 2000 Oe.

5. The apparatus of claim 2, wherein the ultrasound intensity is no more than 750 milliWatts per square centimeter (mW / cm2) for the ultrasound waves.

6. The apparatus of claim 1 , wherein the MADG device comprises: a body having at least one piezoelectric layer between a first side and a second side, the first side having a plurality of magnetostrictive layers and resin layers and the second side having a plurality of magnetostrictive layers and resin layers.

7. The apparatus of claim 6, wherein the first side has between 3 and 6 magnetostrictive layers and between 3 and 6 resin layers and the second side has between 3 and 6 magnetostrictive layers and between 3 and 6 resin layers.

8. The apparatus of claim 6, wherein the piezoelectric layer is comprised of Mn02 andCuO co-doped Pb(In,Nb)O3-Pb(Mg,Nb)O3-PbTiO3 (PIN-PMN-PT) material.

9. The apparatus of claim 8, wherein the piezoelectric layer is a disk-shaped transducer, a square shaped transducer, a rectangular shaped transducer, a disk shaped layer, a square shaped layer, or a rectangular shaped layer.

10. The apparatus of claim 6, wherein the MADG device also comprises: a coating that encapsulates the piezoelectric layer, the first side, and the second side.

11. The apparatus of claim 10, wherein the coating is a polydimethylsiloxane (PDMS) coating or a chlorinated poly(para-xylylene) polymer coating.

12. The apparatus of claim 6, wherein the at least one piezoelectric layer is lead-free.

13. The apparatus of claim 6 or claim 12, wherein the plurality of resin layers of the first side include nanoparticles of magnetic material.

14. The apparatus of claim 6, claim 12, or claim 13, wherein the plurality of resin layers of the second side include nanoparticles of magnetic material.

15. The apparatus of claim 6, wherein the first side includes nanoparticles of magnetic material and / or the second side includes nanoparticles of magnetic material.

16. The apparatus of any of claims 6-15, wherein the MADG device also comprises an electrode attached to the first side and / or an electrode attached to the second side.

17. The apparatus of claim 16, wherein the electrode attached to the first side iscomprised of a metal paste and / or the electrode attached to the second side is comprised of a metal paste.

18. The apparatus of claim 17, wherein the metal paste is platinum (Pt) paste, silver / palladium (Ag / Pd) paste, Ag past, Au paste, Ni paste, and / or Cu paste.

19. The apparatus of any of claim 6 or any of claims 12-18, wherein the at least one piezoelectric layer is comprised of a biopolymeric material.20 The apparatus of claim 19, wherein the biopolymeric material is compatible with a body of an animal.

21. The apparatus of claim 6 or any of claims 12-19, wherein the MADG device is sized to be a nanoparticle.

22. The apparatus of claim 1, comprising: a battery connected to the MADG device; and / or at least one capacitor connected to the MADG device; and / or at least one supercapacitor connected to the MADG device.

23. The apparatus of claim 1, wherein the MADG device is integrated into an implantable medical device (IMD) or is connected to an electrical energy storage device of a remote device for recharging the electrical energy storage device.

24. The apparatus of claim 23, wherein the electrical energy storage device is a rechargeable battery.

25. A process for wireless energy harvesting comprising:generating voltage in response to exposure to a magnetic field, the magnetic field having an alternating current (AC) magnetic field strength that is less than or equal to 5.5 Oe or having a direct current (DC) magnetic field strength that is less than or equal to 2000 Oe; generating voltage in response to exposure to ultrasound waves, the ultrasound waves having an ultrasound intensity that is no more than 750 milliwatts per square centimeter (mW / cm2); wherein the generating of the voltage in response to the exposure to the magnetic field and the generating of the voltage in response to the exposure to the ultrasound waves occurs simultaneously via a magnetic field and ultrasound induced dual generator (MUDG) device.

26. The process of claim 25, comprising: positioning the MUDG device in a body of an animal.

27. The process of claim 25, comprising: integrating the MUDG device into a remote device positionable in or adjacent to a facility.

28. The process of claim 25, comprising: fabricating the MUDG device so that the MUDG device comprises: a body having a piezoelectric layer between a first side of the body and a second side of the body, the first side having a plurality of magnetostrictive layers and resin layers and the second side having a plurality of magnetostrictive layers and resin layers.

29. The process of claim 28, wherein the piezoelectric layer is comprised of Mn02 and CuO co-doped Pb(In,Nb)O3-Pb(Mg,Nb)O3-PbTiO3 (PIN-PMN-PT) material; or wherein the piezoelectric layer is comprised of PZT material, PMN-PZT material, PMN-PT material, BT material or PZN-PT material.

30. The process of claim 28, wherein the fabricating of the MUDG device is performed so that the MUDG device also comprises a coating that encapsulates the piezoelectric layer, the first side, and the second side.

31. The process of claim 25, comprising: feeding the generated voltage generated via the magnetic field and the ultrasound waves to a battery to recharge the battery or to an electrical energy storage device to recharge the electrical energy storage device.

32. The process of claim 31, wherein the electrical energy storage device is a rechargeable battery.

33. A process for wireless energy harvesting comprising: generating voltage in response to exposure to a magnetic field and also generating voltage in response to exposure to acoustic waves simultaneously via a magnetic field and acoustic wave induced dual generator (MADG) device.

34. The process of claim 33, comprising: feeding the generated voltage generated via the magnetic field and the acoustic waves to an electrical energy storage device to recharge the electrical energy storage device.

35. The process of claim 33, also comprising: generating voltage in response to exposure to a magnetic field via the MADG device for feeding to an electrical energy storage device, the magnetic field having an alternating current (AC) magnetic field strength that is less than or equal to 5.5 Oe or having a direct current (DC) magnetic field strength that is less than or equal to 1670 Oe; and generating voltage in response to exposure to acoustic waves via the MADG device for feeding to the electrical energy storage device.

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