Publications de Zvonimir Sipus

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

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

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, James Daniel Rosenthal, Mingxiang Gao, Kangling Wu, Zvonimir Sipus

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, Mingxiang Gao, Zvonimir Sipus, 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, Mingxiang Gao, Zvonimir Sipus

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, Mingxiang Gao, Zvonimir Sipus

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

Design Concerns for In-body Antennas Based on Frequency Analysis of Fundamental Radiation Limitations

Anja Skrivervik, Denys Nikolayev, Zvonimir Sipus

Fundamental radiation limitations of in-body or implantable antennas should give us an estimate on the feasibility of some desired system. It was shown that near-field effects and distance to the body - freespace boundary are critical aspects, while the sh ...

IEEE2020

Antenna design for a cranial implant

Anja Skrivervik, Miroslav Veljovic, Ismael Vico Triviño, Zvonimir Sipus

This contributions presents the design process for an antenna designated for the telemetry in a cranial implant. Issues like physical limitation, simulation problems and design strategies will he addressed and final design presented. ...

IEEE2020

Antenna for a Cranial Implant: Simulation Issues and Design Strategies

Anja Skrivervik, Miroslav Veljovic, Ismael Vico Triviño, Zvonimir Sipus

The design of a specific antenna for a cranial implant is used to illustrate design and simulation issues linked to implantable antennas. After a brief introduction, we will review the requirements for the antenna, and go through the design process, discus ...

IEEE2020

Optimal Frequency of Operation and Radiation Efficiency Limitations of Implantable Antennas

Anja Skrivervik, Denys Nikolayev, Zvonimir Sipus

Fundamental limits on radiation performance of implantable antennas serve as the design quality gauge, facilitate the choice of the antenna type, and provide simple design rules to maximize the radiation performance. This study obtains the limits using two ...

IEEE2020

Radiation Limitations for Small Implanted Antennas

Anja Skrivervik, Zvonimir Sipus

Medical implants with communication capability are becoming increasingly popular with today’s trends to continuously monitor patient’s condition. This is a major challenge for antenna designers since the implants are inherently small and placed in a commun ...

IEEE2019

Fundamental Limits for Implanted Antennas: Maximum Power Density Reaching Free Space

Anja Skrivervik, Zvonimir Sipus

Medical implants with communication capability are becoming increasingly popular with today’s trends to continuously monitor patient’s condition. This is a major challenge for antenna designers since the implants are inherently small and placed in a commun ...

2019

Electrically small antenna design: from mobile phones to implanted sensors

Anja Skrivervik, Zvonimir Sipus

In this review, intended to introduce the convened session on electrically small antennas, we describe the evolution of electrically small antennas from the early nineties, when the boom of mobile phones triggered an intense research activity on the, to ou ...

The European Association on Antennas and Propagation (EurAAP)2019

Design Tools for Small Implantable antennas

Anja Skrivervik, Ismael Vico Triviño, Zvonimir Sipus

Implantable applications have been increasing in number in an exponential manner since the turn of the millennium. This is largely due to the increasing availability of ultra low power consumption electronics, enabling the emergence of healthcare services ...

The European Association on Antennas and Propagation (EurAAP)2018

Design Considerations for Wearable Antennas

Anja Skrivervik, Jovanche Trajkovikj, Benjamin Fuchs, Zvonimir Sipus

With the development of generalized connectivity and the increased use of Body Area Networks, wearable antennas have become ubiquitous in the last decade. Their design presents a challenge, as they per definition are located at the interface between free s ...

Ieee2016