This paper concerns the designing, considerations and analysis of H-plane Y junction in rectangular substrate integrated waveguide technology using HFSS code. The proposed design unites the advantages such as low fabrication cost, low signal losses, planer profile, easily integrated with the other microwave devices and high performance in microwave application. The transmission coefficients S₂₁ and S ₃₁ shows that the input power (3W) in a waveguide is equally split into -8dB power or combined -8dB power in needed manner by using presented SIW Y junction. The divided E-fields are in same phase as the E-field at the input. The junction is optimized in C-band [4-8 GHz] at super high frequency of 7 GHz. The proposed SIW Y junction is designed on RT Duroid substrate and the measured results demonstrate that The return loss is -44.5668 dB, VSWR at the output port is 1.1 & 1.2 and reflection loss is 0.0059 dB at 7.9 GHz frequency. Thus, through the study of results, proposed SIW Y junction is very effective for signal transmission with low losses over entire C-band.