Implantable Antenna in Medical Devices Using DGS & Holy Superstate

Abstract

Implantable antennas are essential components for wireless biomedical applications that require reliable communication and low power consumption. However, designing such antennas poses several challenges, such as miniaturization, circular polarization, gain enhancement, and biocompatibility. In this report, we propose a novel approach to address these challenges by using a defected ground structure (DGS) and a holey superstrate on an ultra-compact antenna. The proposed antenna operates in the industrial, scientific, and medical (ISM) band of 2.4 GHz and has a dimension of 2.5 mm × 2.5 mm × 1.28 mm (8 mm3). The DGS and the holey superstrate are used to generate circular polarization and to improve the gain of the antenna, respectively. The antenna is fabricated on a low-loss, flexible, and biocompatible substrate (Taconic CER- 10) and tested numerically and experimentally. The results show that the antenna achieves a good impedance matching with a bandwidth of 33%, a maximum peak gain of -16.2 dBi, and a radiation efficiency of 0.25%. Moreover, the antenna has a low specific absorption rate (SAR) that complies with the IEEE standard safety guidelines. To the best of our knowledge, the proposed antenna is the most compact circularly polarized implantable antenna with high performance and significant gain enhancement (approximately 3.2 dBi) compared to previously reported works.