A low-profile linear array antenna having an end-fed series-fed structure for high gain with a wide fan beam was proposed. The conventional microstrip antenna, a series-fed patch antenna, and the proposed antenna were analyzed with an omnidirectional radiating magnetic current, and a wide fan beam was created using a coupled slit-ring resonator. The antenna array consists of 72Ω microstrip lines and four slit-ring resonators acting as radiating elements. The proposed antenna was fabricated and measured. The proposed antenna has measured results, the peak gain is 10.3 dB, and the half-power beam-width(HPBW) of E-plane is 129°. The proposed antenna has linear polarization, a wide fan-beam, and high gain.