Publications by Zvonimir Sipus

Radiation Patterns of RF Wireless Devices Implanted in Small Animals: Unexpected Deformations Due to Body Resonance

Anja Skrivervik, Stéphanie Lacour, Mingxiang Gao, Zvonimir Sipus, German Augusto Ramirez Arroyave, Kangling Wu, James Daniel Rosenthal

One challenge in designing RF wireless bioelectronic devices is the impact of the interaction between electromagnetic waves and host body tissues on far-field wireless performance. In this paper, we investigate a peculiar phenomenon of implantable RF wirel ...

2023

Analytic Approximation of In-Body Path Loss for Implanted Antennas

Anja Skrivervik, Mingxiang Gao, Zvonimir Sipus

Implantable bioelectronic devices predominantly use wireless links for communication and/or power transfer. When considering transmitting implanted antennas, electromagnetic radiation through biological media is highly attenuated, and previous work has sho ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2023

Radiation Performance of Antennas Implanted in Small Animals for Neuroengineering

Anja Skrivervik, Stéphanie Lacour, Mingxiang Gao, Zvonimir Sipus, Kangling Wu, James Daniel Rosenthal

Wireless data communication could improve the performance and reliability of biomedical implants used in fundamental neuroscience research by removing infection-prone transcutaneous cabling. The small size of common research animals like mice and rodents, ...

IEEE2023

Wireless Powering Efficiency of Deep-Body Implantable Devices

Anja Skrivervik, Denys Nikolayev, Zvonimir Sipus, Mingxiang Gao, Erdem Cil

The wireless power transfer (WPT) efficiency to implanted bioelectronic devices is constrained by several frequency-dependent physical mechanisms. Recent works have developed several mathematical formulations to understand these mechanisms and predict the ...

Institute of Electrical and Electronics Engineers2022

On the Maximum Power Density of Implanted Antennas within Simplified Body Phantoms

Anja Skrivervik, Mingxiang Gao, Zvonimir Sipus

With the application requirements of wireless technology in implantable bioelectronics, knowledge of the fundamental limits for implanted antennas becomes critical. In this work, we investigated the variation of maximum power density within simplified body ...

IEEE2022

Rules of Thumb to Assess Losses of Implanted Antennas

Anja Skrivervik, Denys Nikolayev, Zvonimir Sipus, Mingxiang Gao

Fundamental limits for implanted antennas should be able to evaluate the bounds on losses with the knowledge of physical limitations from antenna and tissue parameters. In this work, rules of thumb to assess losses of deeply implanted antennas are presente ...

IEEE2021

Influence of Uncertainty of Body Permittivity on Achievable Radiation Efficiency of Implantable Antennas-Stochastic Analysis

Anja Skrivervik, Zvonimir Sipus

Design of medical sensor implants is very challenging due to numerous restrictions in terms of size and biological acceptability. In addition, large absorption and reflection of electromagnetic waves in body tissues significantly degrades the communication ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2021

Physical Bounds on Implant Powering Efficiency Using Body-Conformal WPT Systems

Anja Skrivervik, Denys Nikolayev, Zvonimir Sipus, Mingxiang Gao

The efficiency of an on-body wireless power transfer system for implant powering is defined by how the electromagnetic energy interacts with the lossy, heterogeneous, and dispersive body tissues. The objective of this study is to discuss the methodology an ...

IEEE2021

In-body Antennas Design Based on Fundamental Limits of Obtainable Power Density

Anja Skrivervik, Zvonimir Sipus

In-body medical implants are one of the most promising solutions for increasing patient healthcare in the future. Many such devices already exist, however, each new design is a challenge due to size constraints and communication issues which arise due to s ...

IEEE2021

Uncertainty Estimation of Achievable Radiation Efficiency of Implantable Antennas

Anja Skrivervik, Zvonimir Sipus

Designing antennas for implanted medical devices is a very complex task where one needs to tackle inherently large EM absorption in the human tissue and very limited available space for the antenna. In addition, designers need to carefully limit the power ...

IEEE2021