In this article, a step-sized Substrate Integrated Waveguide (SIW) is designed, simulated, and a prototype is developed for performance validation. The various parameters of the SIW, like propagation constants, modal field distribution, etc., are analyzed and investigated. An antenna is designed and developed using the proposed SIW. The various important parameters of the designed stepped SIW antenna, such as return loss, total antenna gain, radiation pattern, radiation efficiency, etc., are determined and validated through experimental standers. The antenna is simulated using a commercially available finite element method-based high frequency structural simulator. The designed antenna shows the wideband frequency response from 6 GHz to 22 GHz in the simulating frequency range. The designed structure shows the various resonant frequencies. A minimum return loss of -39 dB is achieved at a frequency of 17 GHz. Overall, the gain of the antenna is high. The total maximum gain achieved by this antenna is around 12.5 dBi. The developed antenna offers high efficiency on the FR4 substrate.