Flexible and Wearable Antenna for Biomedical Application: Progress and Opportunity

In recent years, wearable antenna demand in biomedical applications has increased drastically. Several effective techniques and efficient structures of antenna were proposed to overcome the challenges with respect to the vicinity of the human body. In this paper, substrate and conductive material for the wearable antenna are reviewed thoroughly to ensure that it operates consistently and with flexibility. The design of wearable antennas becomes challenging when flexible substrates are examined, better conductive materials are employed during manufacturing processes and the issue exists in body-worn implementation. To address these issues in this paper, exhaustive literature is carried out based on validated characteristics such as Specific Absorption Rate (SAR), gain, and bandwidth by employing radiating structure, feed, ground, and slot optimization. Effective topologies for gain enhancement, bandwidth enhancement, and SAR reduction for various wearable antenna designs on biomedical applications were reviewed through qualitative study. This extensive study on flexible and wearable technology explores the various problems and challenges involved while designing suitable antennas are discussed. This review paper also highlights the advancements in 5G technology, applications on ISM band and IOT, with particular emphasis on wearable antennas and their potential applications in the biomedical field.