Abstract: A broadband differential to single-ended power divider based on substrate integrated suspended slot line is proposed in this paper. The transition from slot line and differential microstrip pair is adopted, and the interconnection between differential circuits and single-ended circuits is realized. It has inherent common mode suppression in a wide working frequency range. In the frequency range from 10.52 GHz to 15.58 GHz, the measured return loss at the differential port is better than 10 dB. The isolation between the output ports is above 15 dB between 10.1 GHz and 15 GHz. In the differential working mode, the output signal of power divider is equal in amplitude and opposite in phase. The designed circuit is based on the multi-layer structure, and the core circuit including slot line and transition structure is suspended in the air cavity,which has the advantages of self-packaging and low radiation loss.