Substrate integrated waveguide (SIW) horn is a good planar feeding structure for planar antennas and arrays. In this letter, a 18 printed log-periodic dipole array (LPDA) antenna fed by a compact SIW horn is presented. Some linear arrays of metal vias are embedded inside the SIW horn to correct the phase and amplitude distributions on the horn aperture. The measured gain of the proposed antenna is 9.61 dBi, the half power beam-width is 18.1, the FTBR is 17.55 dB, the cross polarization in the axis direction is 21.48 dB, and the side-lobe lever is −14.93 dB at 10 GHz. Good agreement between the simulated and the measured results is obtained.