Magnetoelectric Versus Inductive Power Delivery for Sub-mm Receivers

Khalif, Adam; Nasrollahpour, Mehdi; Sun, Neville; Zaeimbashi, Mohsen; Chen, Huaihao; Liang, Xianfeng; Alemohammad, Milad; Etienne‐Cummings, Ralph; Sun, Nian X.; Cashl, Sydney

doi:10.1109/wptc51349.2021.9458201

Cited by 7 publications

(6 citation statements)

References 12 publications

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“…As for the ultra-small receiver (Rx) coil, there are three known methods of connecting it to the CMOS ASIC [ 9 ]: around CMOS (wire wound around the CMOS chip), in CMOS (fully integrated coils), and above CMOS (on top of CMOS substrate). The in-CMOS coil offers cost effectiveness, smaller volume, and ease of mass production but suffers from poor PTE (primarily due to substrate leakage) [ 10 ]. The around-CMOS coil offers a very high-quality factor (Q) but has variability in its electrical properties, making it challenging to resonate at a specific frequency [ 2 ].…”

Section: Methodsmentioning

confidence: 99%

Fabrication and Assembly Techniques for Sub-mm Battery-Free Epicortical Implants

et al. 2023

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Over the past three decades, we have seen significant advances in the field of wireless implantable medical devices (IMDs) that can interact with the nervous system. To further improve the stability, safety, and distribution of these interfaces, a new class of implantable devices is being developed: single-channel, sub-mm scale, and wireless microelectronic devices. In this research, we describe a new and simple technique for fabricating and assembling a sub-mm, wirelessly powered stimulating implant. The implant consists of an ASIC measuring 900 × 450 × 80 µm3, two PEDOT-coated microelectrodes, an SMD inductor, and a SU-8 coating. The microelectrodes and SMD are directly mounted onto the ASIC. The ultra-small device is powered using electromagnetic (EM) waves in the near-field using a two-coil inductive link and demonstrates a maximum achievable power transfer efficiency (PTE) of 0.17% in the air with a coil separation of 0.5 cm. In vivo experiments conducted on an anesthetized rat verified the efficiency of stimulation.

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Section: Methodsmentioning

confidence: 99%

Fabrication and Assembly Techniques for Sub-mm Battery-Free Epicortical Implants

et al. 2023

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“…The need of aggressive miniaturization of antennas and circuits limits the wireless power transfer for energy harvesting within implants. References [ 59 ] and [ 60 ] have shown that low gigahertz frequencies are well-suited for wireless power transfer to millimeter-sized implantable devices. Reference [ 61 ] presented a mm-size neural implant utilizing magnetoelectric effects for highly efficient power and data transfer, and [ 62 ] exhibits a wireless millimetric magnetoelectric implant to receive power and data for peripheral nerve stimulation.…”

Section: Introductionmentioning

confidence: 99%

Circuit-Level Modeling and Simulation of Wireless Sensing and Energy Harvesting With Hybrid Magnetoelectric Antennas for Implantable Neural Devices

Das

Nasrollahpour

et al. 2023

IEEE Open J. Circuits Syst.

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A magnetoelectric antenna (ME) can exhibit the dual capabilities of wireless energy harvesting and sensing at different frequencies. In this article, a behavioral circuit model for hybrid ME antennas is described to emulate the radio frequency (RF) energy harvesting and sensing operations during circuit simulations. The ME antenna of this work is interfaced with a CMOS energy harvester chip towards the goal of developing a wireless communication link for fully integrated implantable devices. One role of the integrated system is to receive pulsemodulated power from a nearby transmitter, and another role is to sense and transmit low-magnitude neural signals.The measurements reported in this paper are the first results that demonstrate simultaneous low-frequency wireless magnetic sensing and high-frequency wireless energy harvesting at two different frequencies with one dual-mode ME antenna. The proposed behavioral ME antenna model can be utilized during design optimizations of energy harvesting circuits. Measurements were performed to validate the wireless power transfer link with an ME antenna having a 2.57 GHz resonance frequency connected to an energy harvester chip designed in 65nm CMOS technology. Furthermore, this dual-mode ME antenna enables concurrent sensing using a carrier signal with a frequency that matches the second 63.63 MHz resonance mode. A wireless test platform has been developed for evaluation of ME antennas as a tool for neural implant design, and this prototype system was utilized to provide first experimental results with the transmission of magnetically modulated action potential waveforms. W

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“…Magnetoelectric (ME) receivers are a promising solution for powering implantable bioelectronics because, compared to other WPT modalities, they have the potential to deliver higher power to smaller devices with better alignment tolerance and minimal signal attenuation through air or tissue 19 . While ME materials have been explored for compact antennas 22,23 , only recently have ME materials been used for WPT in bioelectronics, demonstrating up to 2 mW of power delivery 15,[24][25][26][27][28] . The ME receivers most commonly used to power bioelectronics are multilayer laminates that convert magnetic energy into electrical energy through mechanical coupling between magnetostrictive and piezoelectric layers 15,[24][25][26][27][28] .…”

Section: Introductionmentioning

confidence: 99%

“…While ME materials have been explored for compact antennas 22,23 , only recently have ME materials been used for WPT in bioelectronics, demonstrating up to 2 mW of power delivery 15,[24][25][26][27][28] . The ME receivers most commonly used to power bioelectronics are multilayer laminates that convert magnetic energy into electrical energy through mechanical coupling between magnetostrictive and piezoelectric layers 15,[24][25][26][27][28] . This conversion is most efficient when the frequency of the magnetic field matches an acoustic resonant frequency of the ME receiver, thereby generating the maximum voltage and power [26][27][28][29] .…”

Section: Introductionmentioning

confidence: 99%

Magnetoelectrics Enables Large Power Delivery to mm-Sized Wireless Bioelectronics

Kim,

Tuppen,

Alrashdan

et al. 2023

Preprint

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To maximize the capabilities of minimally invasive implantable bioelectronic devices, we must deliver large amounts of power to small implants; however, as devices are made smaller, it becomes more difficult to transfer large amounts of power without a wired connection. Indeed, recent work has explored creative wireless power transfer (WPT) approaches to maximize power density (the amount of power transferred divided by receiver footprint area (length x width)). Here, we analyzed a model for WPT using magnetoelectric (ME) materials that convert an alternating magnetic field into an alternating voltage. With this model, we identify the parameters that impact WPT efficiency and optimize the power density. We find that improvements in adhesion between the laminated ME layers, clamping, and selection of material thicknesses lead to a power density of 3.1 mW/mm2, which is over 4 times larger than previously reported for mm-sized wireless bioelectronic implants at a depth of 1 cm or more in tissue. This improved power density allows us to deliver 31 mW and 56 mW to 10-mm2 and 27-mm2 ME receivers, respectively. This total power delivery is over 5 times larger than similarly sized bioelectronic devices powered by radiofrequency electromagnetic waves, inductive coupling, ultrasound, light, capacitive coupling, or previously reported magnetoelectrics. This increased power density opens the door to more power-intensive bioelectronic applications that have previously been inaccessible using mm-sized battery-free devices.

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Magnetoelectric Versus Inductive Power Delivery for Sub-mm Receivers

Cited by 7 publications

References 12 publications

Fabrication and Assembly Techniques for Sub-mm Battery-Free Epicortical Implants

Fabrication and Assembly Techniques for Sub-mm Battery-Free Epicortical Implants

Circuit-Level Modeling and Simulation of Wireless Sensing and Energy Harvesting With Hybrid Magnetoelectric Antennas for Implantable Neural Devices

Magnetoelectrics Enables Large Power Delivery to mm-Sized Wireless Bioelectronics

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