This paper proposes a wideband slot antenna design based on the substrate integrated gap waveguide technology for millimetre wave applications. The proposed antenna is realized using the H-shaped slot (H-slot) to improve impedance bandwdith. Simulation results show that the proposed antenna has an impedance bandwidth at S11 ≤−15 dB from 24−29.5 GHz resulting in a 20.5% fractional bandwidth. Hence, the designed slot antenna can potentially be used as the radiating element of an array antenna for fixed-beam point-to-point applications.