Showing papers by "Zvonimir Sipus published in 2023"
TL;DR: In this article , the authors presented a simplified model of an implanted antenna that provides closed-form approximate expressions to estimate EM radiation from the implant, and extended the expressions for the reactive near-field losses to both deep and shallow implants, by taking into account the implantation depth.
Abstract: 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 shown that the in-body path loss can be separated into three parts: the losses incurred by the propagating fields, the reflections at media interfaces, and the coupling of the antenna reactive near field and the lossy body. The first two are unavoidable, but a careful antenna design should minimize the near-field losses. Thus, quantifying the near-field losses of implanted antennas is useful in selecting the antenna topology for preliminary design. The aim of this paper is to present a simplified model of an implanted antenna that provides closed-form approximate expressions to estimate EM radiation from the implant. In particular, we extend the expressions for the reactive near-field losses to both deep and shallow implants, by taking into account the implantation depth. Additionally, the proposed approximate method is verified by comparing the results obtained with the full-wave simulations in the case of a miniature implanted antenna, and with both simulated and measured results from two practical examples found in the literature.
26 Mar 2023
TL;DR: In this article , the authors demonstrate how the far-field radiation performance of an antenna implanted in a rat cadaver is impacted by the electrically small size of the rat's body.
Abstract: 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, however, presents an additional challenge in the design of implantable antennas due to the resonance effects of the host body. In this work, we demonstrate how the far-field radiation performance of an antenna implanted in a rat cadaver is impacted by the electrically small size of the rat’s body. We further discuss design strategies for developing implantable antennas in small animals to obtain robust wireless link budgets for the considered size- and energy-constrained wireless implantable systems.
26 Mar 2023
TL;DR: In this paper , the transition from a classic coaxial line into a waveguide remains an open problem and the aim of this paper is to consider and experimentally characterize different possibilities for making this transition.
Abstract: One of the major challenges in the development of wearable antennas is to design an antenna that can at the same time satisfy technical requirements and be aesthetically acceptable and suitable for clothing applications. Slotted waveguide antennas made of conductive textiles meet all the demands for integration into clothing. However, the transition from a classic coaxial line into a waveguide remains an open problem and the aim of this paper is to consider and experimentally characterize different possibilities for making this transition.