A Miniaturized Wearable Annular Slot Antenna Based on Designer LSPs for Telemedicine Communication

A compact multiband wearable antenna based on designerlocalized surface plasmons (designer LSPs) is proposed for future wirelessbody sensor networks (WBSNs). By periodically loading rectangular-corrugated metal-insulator-metal (MIM) structures that can supportLSPs modes around the circular slit of an annular slot antenna,the antenna effectively reduces its dimension and achieves multibandcharacteristics. Meanwhile, an open S-shaped corrugated MIM waveg-uide structure is proposed for validating that the LSPs modes areoriginating from the Fabry-Perot resonances. Furthermore, a circularmetallic disk is introduced at the end of the microstrip feedline, whichcan enhance electromagnetic energy coupling and improve impedancematching and radiation efficiency. Simulated and measured resultsdemonstrate that the proposed antenna produces five operating bands,including 1.60-1.64 GHz, 3.49-3.58 GHz, 4.78-5.01 GHz, 6.16-6.63 GHz,and 7.25-7.61 GHz, with a peak gain of 5.19 dBi. The antenna dimensionis only 45x40 mm (about 0.24 lambda gx0.21 lambda g). The maximum specificabsorption rate (SAR) value of human tissue complies with IEEEguidelines for safety radiation standards. This work explores the far-fieldradiation characteristics of designer LSPs in wearable antennas, whichcan find many applications, including healthcare monitoring systems andtelemedicine communication fields