In-vitro testing and circuit analysis of an ultra-miniaturized biosensor for multiple medical implant systems

Abstract

This paper presents an ultra-miniaturized and flexible biosensor for multiple medical implant systems, operating in the 2.4 GHz Industrial, Scientific, and Medical (ISM) band. A flexible Rogers RO Duroid 3010 material with a dielectric constant (εr) 10.2, loss tangent (δ) 0.0022 and thickness of 0.635 mm is utilised as a substrate and superstrate for the proposed biosensor. The size of an biosensor is 10 mm × 10 mm. Certain design elements are employed to accomplish a miniaturized geometry, such as a slotted radiating patch and ground plane, a flexible substrate and superstrate material. A realistic simulation environment has been utilized to evaluate the performance of the proposed biosensor in multiple tissues, encompassing both homogeneous and heterogeneous situations within different organs. This enables the examination and advancement of the practicality of several implantable applications. The proposed biosensor is validated by making an equivalent circuit. The biosensor exhibits a higher gain of −13.18 dB and a higher bandwidth of 16.52 % at the desired ISM band. To test the practicality of a proposed biosensor, in-vitro measurements have been carried out using different tissue-mimicking phantoms. Moreover, a proposed biosensor’s specific absorption rate (SAR) in multiple tissues has also been calculated. The proposed biosensor demonstrates a good correlation between simulated and measured results, which makes the biosensor an excellent choice for implantation inside multiple medical implant devices.