Abstract: In millimeter-wave(MM-W)system on package (SOP), a broadband and miniaturized vertical interconnection circuit is required, for the MM-W signal's transition between different functional layers. Different from normal substrate integrated waveguide (SIW), a novel Z-direction substrate integrated rigged waveguide (SIRW) is proposed, which is used for making up of the vertical interconnection. The interconnection structure is compatible with standard PCB manufacturing process, and can be realized with the substrate synchronously. Finally, a back-to-back circuit is fabricated in LTCC substrates. The dimension of port is 2.2 mm′1.3 mm. In 28~36 GHz band, the insertion loss is less than 0.45 dB, vibration is less than ±0.5 dB , and return loss is better than -12 dB.