This paper presents the design and implementation of a blade dipole antenna to be used in radio astronomy with a design-oriented to detect the 21 cm signal. The design and simulation of the antenna were carried out using the High-Frequency Structure Software (HFSS) to determine the behavior of the scattering and immittance parameters, and the radiation patterns. Parametric analyses were performed on different antenna dimensions to obtain the best frequency response with respect to bandwidth and S11. The antenna comprises a radiating element and a ground plane implemented in copper with ground plane support to separate them. The antenna was scaled due to size limits in the construction and characterized using a Vector Network Analyzer (VNA) in the frequency range of 400-1800 MHz. The results obtained in the measurement and simulation are similar and suitable for the antenna to work in a radio telescope.