Circuit modelling and validating a capacitively loaded implantable antenna with its sensitivity analysis for biomedical applications

Abstract This paper presents a flexible and capacitively loaded implantable antenna with its sensitivity analysis for biomedical applications. The proposed antenna is designed to operate within the ISM (Industrial, Scientific, and Medical) band, which ranges from 2.4 to 2.48 GHz. The overall dimensions of an antenna are 8 × 8 × 0.25 mm 3 . The substrate material FR-4 is utilised with a dielectric constant ( ε r ) 4.4, loss tangent ( δ ) 0.0022 and a thickness of 0.25 mm for the proposed antenna. An ultra-flexible superstrate material, Parylene C, is used with a thickness of 40 microns on both sides of an antenna to avoid direct contact of metallization with human tissue. Further, the proposed antenna is initially implanted inside a four-layer cubic (FLC) phantom, and then its parameters are validated using the CST Hugo voxel model. The simulated bandwidth of an antenna is 28.16 %, whereas measured bandwidths are 32.25 % inside the tissue-mimicking phantom and 64 % inside minced pork. Moreover, assessing the specific absorption rate (SAR) in a realistic model ensures patient safety by following the guidelines outlined in C95.1–1999 for 1g and 10g of tissue. The simulated and measured results are in close agreement, making the designed antenna appropriate for biomedical applications.