A compact 5G wideband antenna for body-centric network (BCN) operating on Ka band has been presented in this paper. The design of the antenna consists of a very simple key-shaped radiator patch with a vertical slot for better impedance matching. The antenna was designed and simulated with the help of the Computer Simulation Technology (CST) Microwave Studio Suite, a well-liked and dependable electromagnetic simulation program running on Microsoft Windows. Free-space simulation produces a resonant frequency at 28 GHz, which falls under the Ka band and 5G’s n257, more precisely n261. The proposed antenna has a size of
1.24
λ
×
0.6
λ
×
0.153
λ
and has a wider impedance bandwidth of more than 20 GHz. The antenna’s gain and radiation efficiency are 3.87 dBi and 70%, respectively, at the resonant point. Further parametric studies reveal that the antenna can be activated in the V-band by increasing the feedline width. The antenna is proposed for the application of BCN. Therefore, a three-dimensional human torso phantom was developed virtually to test on-body performance. The on-body findings of this antenna were resimulated by positioning the antenna in close proximity to the three-layer human body model, where 22.5 dB of on-body reflection coefficient was recorded at 28 GHz. Simulated on-body gain and efficiency were 4.56 dBi and 61.33 percent, respectively. A distance-based investigation was conducted to investigate the impacts of the human body’s presence by positioning the antenna at five different distances from the human torso model. The findings were compared to assess how distance affects its behaviors. The antenna’s gap was kept at 6 mm for the optimum results, which included 4.83 dBi of gain with a 66 percent efficiency and a recorded RL value of about 23 dB. The on-body simulations produced very consistent results with a slight deviation after 26.5 GHz, even though the distance was varied.