Design of a conformal fractal antenna with SIW for medical implants application

Abstract

This paper proposed a new design of fractal antenna with Substrate Integrated Waveguide (SIW) and dual-resonant for wireless implantable capsule systems. The proposed antenna conforms to an implantable capsule with an 11 mm radius and 25 mm length without occupying the capsule's internal space. the proposed antenna has four slots and a fractal shape for extending the effective current path. The substrate is using Rogers 5880, with 2.2 as relative permittivity and 0.787 mm thickness, while the capsule is made of medical Teflon plastic. This proposed design achieves conformal characteristics with human tissue compatibility. Computer simulation technology (CST) software was used to simulate and analyze the antenna in different variety of environments. At operating frequency of 2.4. GHz and 5.8 GHz industrial, scientific and medical (ISM). The antenna’s bandwidth reach (2.1 GHz-2.3 GHz) and (5.42 GHz-6.04 GHz). The maximum gains of -7.5 dBi and -5.1 dBi at 5.8 GHz and 2.4 GHz, respectively. Voltage standing wave ratio (VSWR) of 1.2 and 1.17, and front-to-back ratio (FBR) of 20.4 dB and 16.07 at 5.8 GHz and 2.4 GHz, respectively. The antenna was experimentally measured in a minced pork. From the result and analysis, it is confirmed that the proposed antenna is successfully suited for wireless implantable capsule systems.