Wireless implantable biomedical devices (IBDs) are emerging technologies used to enhance patient treatment and monitoring. The performance of wireless IBDs mainly relies on their antennas. Concerns have emerged regarding the potential of wireless IBDs to unintentionally cause tissue heating, leading to potential harm to surrounding tissue. The previous literature examined temperature estimations and specific absorption rates (SAR) related to IBDs, mainly within the context of thermal therapy applications. Often, these studies consider system parameters such as frequency, input power, and treatment duration without isolating their individual impacts. This paper provides an extensive literature review, focusing on key antenna design parameters affecting heat distribution in IBDs. These parameters encompass antenna design, treatment settings, testing conditions, and thermal modeling. The research highlights that input power has the most significant impact on localized temperature, with operating frequency ranked as the second most influential factor. While emphasizing the importance of understanding tissue heating and optimizing antennas for improved power transfer, these studies also illuminate existing knowledge gaps. Excessive tissue heat can lead to harmful effects such as vaporization, carbonization, and irreversible tissue changes. To ensure patient safety and reduce expenses linked to clinical trials, employing simulation-driven approaches for IBD antenna design and optimization is essential.
16 December 2024 in IEEE Transactions on Antennas and Propagation
In this invited paper, the New Technology Directions Committee (NTDC) of the IEEE Antennas and Propagation Society (AP-S) presents new and emerging research directions to commemorate the 70th anniversary of the IEEE Transactions on Antennas and Propagation . The NTDC consists of three Working Groups (WGs); members and collaborators of these groups provide their perspectives on topics related to WG themes in this paper. WG-1 focuses on advancement of materials and manufacturing processes for future antenna applications. WG-2 focuses on advances in communications, sensing and imaging. WG-3 focuses on maximizing the societal impact of wireless connectivity. The discussion in this paper ranges from additive manufacturing techniques and system integration to advanced communications and quantum-based sensing technologies. Numerous applications are explored and a perspective on the digital divide is offered.
Implanted wireless biomedical devices represent a significant advancement in medical technology, offering continuous monitoring and targeted therapy. Antenna design for these devices requires careful modeling to ensure efficiency and safety, addressing challenges such as tissue heating and compliance with safety regulations. Specific absorption rate (SAR) analysis, commonly used to ensure safety, often overlooks factors that influence tissue temperature and heat transfer. Understanding heat generation within tissues due to factors like location, orientation, and radiation power is crucial for optimizing device performance. Simulation-driven design and additional computational and experimental studies are essential for patient safety and effective device evaluation. This article focuses on examining tissue temperature elevation near implanted antennas, specifically a simple dipole antenna, to identify design parameters that significantly impact thermal performance. Key parameters include body phantom type and size, thermal boundary conditions, bioheat model parameters, implantation depth, antenna orientation, and input power. The study aims to provide guidelines for designers on optimizing antenna parameters to accurately predict and manage biological tissue heating. It was found that the size of the phantom, blood perfusion, volume thermal losses, antenna orientation, and input power constitute the major effects on tissue heating. An experimental setup was used to help understand the effect of the antenna’s input power on the temperature distribution in the surrounding high dielectric constant material. A dipole antenna was inserted inside a distilled water tank, and the temperature was measured at three reference points surrounding the antenna. Simulation and measurement results were in good agreement supporting the proposed methodology.