In this paper, a compact wearable Vivaldi antenna resonating at 3.5 GHz is proposed for 5G n77, and n78 bands. It is designed upon a flexible polyester substrate having dielectric constant (εr) of 1.34 and loss tangent (tan δ) of 0.005. The antenna parameters were optimized via parametric analyses using CST software with a size of 45 × 45 × 0.4 mm3 (length × width × height). The antenna is evaluated in terms of reflection coefficient, gain, efficiency, radiation pattern, and surface current density. This antenna attained a maximum simulated gain of 4.7 dBi, and an efficiency of 98 % in the resonating band.
