Compact Low-profile Unidirectional Antenna at 2.45GHz for Body-centric Communications

This paper presents a compact, low-profile unidirectional monopole antenna designed for 2.45 GHz wireless body-centric applications in the Industrial, Scientific and Medical (ISM) band. The antenna consists of a slotted-stepped monopole and a rectangular ground plane. Broadband and stable unidirectional radiation are realized in this antenna due to a shorted side-stub that connects the monopole and the ground plane. The antenna is placed on a phantom designed to simulate a human body. Results show that the antenna’s performance remains good when used on a human body. The impedance bandwidth and radiation performance remain relatively good in both free-space and on the body. This makes the antenna a good candidate as a wearable antenna. Compared to other wearable antennas, the proposed antenna does not require cavity-backed structures, and it also reduces the absorption of radiated energy by the body as compared to the commonly used omnidirectional antennas used as wearable antennas.