We propose a novel structure of a CRLH LW antenna with 45-degree inclined linear polarization for automotive applications. The CRLH LW antenna has been examined in order to achieve high gain by changing the period of the unit cell. The peak gain of the CRLH LW antenna is improved by 1.8, 2.2, and 3.1 dB in the backward, broadside, and forward directions of radiation. Moreover, patches were added to the antenna in order to realize 45-degree inclined linear polarization. A prototype CRLH LW antenna with patches was fabricated, and the radiation of the 45-degree inclined polarization was confirmed by measurements.