Searched for: author%3A%22Rashidi%2C+A.%22
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Rashidi, A. (author), Varkevisser, F. (author), Giagka, Vasiliki (author), Lopes Marta da Costa, T.M. (author), Serdijn, W.A. (author)
Electrical stimulation is proven to be an effective way of neuromodulation in bioelectronic medicine (e.g. cochlear implants, deep brain stimulators, etc.), delivering localized treatment by the means of electrical pulses. To increase the stimulation efficiency and neural-type selectivity, there is an increasing interest to employ non...
abstract 2023
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Rashidi, A. (author), Saccher, M. (author), Karuthedath, Cyril Baby (author), Sebastian, Abhilash Thanniyil (author), Savoia, Alessandro Stuart (author), Lavigne, Frederik (author), Stubbe, Frederic (author), Dekker, R. (author), Giagka, Vasiliki (author)
Aluminum Nitride (AlN) Piezoelectric Micromachined Ultrasonic Transducers (PMUTs) are gaining interest for biomedical implant power due to biocompatibility and lowtemperature processing. However, due to the low piezoelectric coefficient of AlN PMUTs, storage capacitors are often used to accumulate ultrasonic power transferred over an extended...
conference paper 2023
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Saccher, M. (author), Schaijk, Rob van (author), Kawasaki, Shinnosuke (author), Klootwijk, Johan H. (author), Rashidi, A. (author), Giagka, Vasiliki (author), Savoia, Alessandro Stuart (author), Dekker, R. (author)
Capacitive Micromachined Ultrasound Transducers (CMUTs) have many advantages compared to other ultrasonic transducer technologies, especially for implantable devices. However, they require a high bias voltage for efficient operation. To eliminate the need for an external bias voltage, a charge storage layer can be embedded in the dielectric....
conference paper 2023
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Saccher, M. (author), Rashidi, A. (author), Savoia, Alessandro Stuart (author), Giagka, Vasiliki (author), Dekker, R. (author)
In the domain of ultrasonically powered biomedical implants, there is an increasing interest in cm-scale ultrasonic receivers (RX). However, when a single-element transducer is used as the RX transducer, an uneven phase distribution across the RX area can significantly reduce the harvestable power. In this paper, we investigate the impact of...
conference paper 2023
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Rashidi, A. (author), Rivandi, H. (author), Grubor, M. (author), Agostinho, Andre (author), Sadio, Valter (author), Santos, Marcelino (author), Serdijn, W.A. (author), Giagka, Vasiliki (author)
This paper presents a novel multi-channel stimulation backend with a multi-bit delta-sigma control loop, which enables precise adjustment of the stimulation current through modulation of the supply voltage. This minimizes the overhead voltage of series circuitry to the stimulation load and avoids the associated energy loss. Additionally, to...
conference paper 2023
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Pola, M. (author), Giagka, Vasiliki (author), Serdijn, W.A. (author), Demarchi, Danilo (author), Rashidi, A. (author)
This paper presents a new communication method between micro-scale freely floating brain implants based on galvanic coupling (GC), called "Brain-Coupled Communication" (BCC). Since the transmission efficiency based on GC is highly dependent on the system’s geometry and the electromagnetic properties of the tissue, finite element models in COMSOL...
conference paper 2023
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Savoia, Alessandro S. (author), Giustiniano, Domenico (author), Prelini, Carlo (author), Saccher, M. (author), Rashidi, A. (author), Leotti, Alberto (author), Giagka, Vasiliki (author), Ferrera, Marco (author)
Micromachined Ultrasonic Transducers (MUTs) are being explored as power converters in wirelessly powered biomedical implants. This paper investigates the role of mechanical support properties in piezoelectric MUTs (PMUTs) on their power conversion efficiency. For this purpose, a finite element model (FEM) of a PMUT array was developed and...
conference paper 2023
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Rashidi, A. (author), Zamani, M. (author), Mondal, Tanmay (author), Hosseini, Seyedsina (author), Laursen, Kjeld (author), Corbet, Brian (author), Moradi, Farshad (author)
This letter presents an ultrasonically powered dual-wavelength optogenetic device that targets simultaneous excitation and inhibition of neural activities, or in a broader sense, optical stimulation in two distinct wavelengths for targeting different populations of neurons. This can be applied to a variety of neurological disorders. The...
journal article 2023
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Kolovou Kouri, K. (author), Rashidi, A. (author), Varkevisser, F. (author), Serdijn, W.A. (author), Giagka, Vasiliki (author)
In neuromodulation applications, conventional current mode stimulation is often preferred over its voltage mode equivalent due to its good control of the injected charge. However, it comes at the cost of less energy-efficient output stages. To increase energy efficiency, recent studies have explored non-rectangular stimuli. The current work...
conference paper 2022
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Varkevisser, F. (author), Rashidi, A. (author), Lopes Marta da Costa, T.M. (author), Giagka, Vasiliki (author), Serdijn, W.A. (author)
This work proposes a guideline for designing more energy-efficient electrical stimulators by analyzing the frequency spectrum of the stimuli. It is shown that the natural low-pass characteristic of the neuron’s membrane limits the energy transfer efficiency from the stimulator to the cell. Thus, to improve the transfer efficiency, it is proposed...
conference paper 2022
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