A W-band helical antenna element with substrate integrated horn (SIH) using low temperature cofired ceramic (LTCC) technology is proposed in this paper. Using the multilayer process of the LTCC technology, the planar helical antenna is achieved. Furthermore, to calibrate the errors of planar LTCC helical antenna's axial direction mode, which is caused by the fabrication limitations of LTCC technology, the SIH structure has been designed. To verify the theory, the investigations of two LTCC antennas with and without SIH have been given. From the simulated results, the proposed antenna shows a wide impedance bandwidth from 85 to 110 GHz for |S 11 |<-10dB,and a wideband axial radio (AR) bandwidth from 91 to 106 GHz for AR<3 dB respectively. The peak gain is greater than 4.5dBi in the AR bandwidth.