Miniaturized stacked implant antenna design at ISM band with biocompatible characteristics

Abstract

Purpose -A vertically stacked, three layer hybrid Hilbert fractal geometry and serpentine radiatorbased patch antenna is proposed and characterized for medical implant applications at the Industrial, Scientific and Medical band (2.4-2.48 GHz). Antenna parameters are optimised to achieve miniaturized, biocompatible and stable transmission characteristics. The paper aims to discuss these issues. Design/methodology/approach -Human tissue effects on the antenna electrical characteristics were simulated with a three-layer (skin, fat and muscle) human tissue model with the dimensions of 180 × 70 × 60 mm 3 (width × height × thickness mm 3 ). Different stacked substrates are utilized for the satisfactory characteristics. Two identical radiating patches are printed on Roger 3,010 (ε r ¼ 10.2) and Alumina (ε r ¼ 9.4) substrate materials, respectively. In addition, various superstrate materials are considered and simulated to prevent short circuit the antenna while having a direct contact with the metallization, and achieve biocompatibility. Finally, superstrate material of Zirconia (ε r ¼ 29) is used to achieve biocompatibility and long-life. A finite element method is used to simulate the proposed hybrid model with commercially available Ansoft HFSS software. Findings -The antenna is miniaturized, having dimensions of 10 × 8.4 × 2 mm 3 (width × height × thickness mm 3 ). The resonance frequency of the antenna is 2.4 GHz with a bandwidth of 100 MHz at return loss (S11) of better than −10 dB characteristics. Overall, the proposed antenna have 50 Ω impedance matching, −21 dB far field antenna gain, single-plane omni-directional radiation pattern properties and incident power of 5.3 mW to adhere Specific Absorption Rate regulation limit. Originality/value -Vertically stacked three layer hybrid design have miniaturized characteristics, wide bandwidth, biocompatible, and stable characteristics in three layer human tissue model make this antenna suitable for implant biomedical monitor systems. The advanced simulation analysis of the proposed design constitutes the main contribution of the paper.

Advances in Antenna-Based Techniques for Detection and Monitoring of Critical Chronic Diseases: A Comprehensive Review

“…Silicon superstrate with (Er = 3.1) [150] and Alumina superstrate (Er= 9.4) were suggested in [105], [113], Kapton Polyimide in [151]. Zirconia is considered a better option for bio-compatible layer insulation as indicated in [152]. Parylene-C is suggested in [153].…”

E-shape metamaterials embedded implantable antenna for ISM-band biomedical applications

“…The implantable medical devices content not only the antenna but contains other components like sensors, batteries…So to eliminate direct contact with the human body, all components of the IMD are encased in biocompatible materials. There are many biocompatible materials in literature, Silica [25], Ceramic Alumina (𝐴𝑙 A 𝑂 / ) [26][27], Zirconia (𝑍𝑟𝑂 A ) [28], Parylene-C [29]… The specific absorption rate (SAR) evaluates to observe the sensitivity of human tissues to electromagnetic energy, it is necessary to specify the maximum acceptable input power to the antenna [30]. The SAR limit specified in IEEE C95.1: 1999 is 1.6 W/Kg in a SAR 1-g averaging mass while that specified in IEEE C95.1: 2005 has been updated to 2 W/Kg in a 10-g averaging mass [31].…”

E-shape Metamaterials Embedded Implantable Antenna for ISM-band Biomedical Applications

“…The implantable medical devices content not only the antenna but contains other components like sensors, batteries…So to eliminate direct contact with the human body, all components of the IMD are encased in biocompatible materials. There are many biocompatible materials in literature, Silica [25], Ceramic Alumina ( A / ) [26][27], Zirconia ( A ) [28], Parylene-C [29]… The specific absorption rate (SAR) evaluates to observe the sensitivity of human tissues to electromagnetic energy, it is necessary to specify the maximum acceptable input power to the antenna [30]. The SAR limit specified in IEEE C95.1: 1999 is 1.6 W/Kg in a SAR 1-g averaging mass while that specified in IEEE C95.1: 2005 has been updated to 2 W/Kg in a 10-g averaging mass [31].…”