An excitation technology of TE 30 mode in substrate integrated waveguide (SIW) and its application for designing a compact Yagi-Uda antenna array is proposed. Coplanar waveguide (CPW) structure is adopted as the input and two slots of CPW are further extended in the SIW along the third lines in the longitudinal direction to convert the electromagnetic field pattern between the slot and SIW. Therefore, TE 30 mode is successfully excited. A Yagi-Uda antenna array fed by the SIW operating at TE 30 mode is fabricated and measured. A broad impedance bandwidth of 46% (| S 11 | <; -10 dB) ranging from 7.8 to 12.4 GHz is achieved with obtaining a maximum gain of 8.5 dBi. Compared with the traditional SIW antenna array based on TE 10 mode, the higher mode excitation technology not only simplifies the feeding network but also reduces the difficulty of processing.