Design of a compact, wideband, and flexible rhombic antenna using CMA for WBAN/WLAN and 5G applications

The design of a compact, wideband flexible monopole antenna printed on a flexible Kapton polyimide substrate is presented. The proposed antenna consists of two rhombic elements embedded within a square plane as the radiating element. The wide bandwidth is aimed at alleviating potential performance degradations due to its application in an on-body environment. The proposed antenna is designed using two main methods: the method of moments with adaptive cross approximation, and the characteristic mode analysis. The antenna operates from 2.038 to 3.745 GHz, indicating a bandwidth of 1.707 GHz (59.03%). Two dominant resonant frequencies are observed at 2.45 and 3.42 GHz, with realized gain of 3 and 5 dBi, and radiation efficiency of 90% and 83%, respectively. Besides that, the genetic algorithm and particle swarm optimization techniques are used to optimize the antenna and its performance validated via measurements. Besides, in free space, its on-body performance when placed in proximity of a human body phantom is evaluated. Finally, specific absorption rate assessment is performed to ensure the safety of the proposed antenna when operating on human. Results indicate the antenna's suitability for wearable applications to support different wireless standards.