A miniature dielectric loaded wide band circularly polarized implantable antenna with low specific absorption rate for biomedical applications

Abstract

An aperture coupled miniature dielectric loaded wide band circularly polarized implantable antenna is designed in this article. The antenna is proposed to operate in industrial, scientific, and medical band (2.4–2.48 GHz) for implantable biomedical applications. A square alumina ceramic dielectric material is used for miniaturization which leads to improvement of antenna bandwidth and gain. All the parameters of antenna are evaluated in a homogeneous cubic skin box and measured in saline solutions and minced pork both. The designed antenna has a simulated impedance bandwidth (|S11| < −10 dB) and axial ratio bandwidth <3 dB of 22% (2.21–2.75 GHz) and 7.36% (2.35–2.53 GHz), respectively and maximum −28.96 dBi peak gain observed at resonance frequency of 2.445 GHz. The proposed antenna confirms to the safety guidelines of IEEE standards of specific absorption rate (SAR). The simulated SAR is showing a low value of 11.64 W/kg average over 1 g tissue when input power is set to 1 W. Circular polarization, wide band, and very low SAR are the key features of the designed antenna. To validate the proper communication and data telemetry range with receiver antenna, link budget calculation has been done for designed antenna at 7 and 100 kbps data rates.