A strip‐typed patch antenna covered with a dielectric is studied. The antenna is excited with a differential feeding mechanism to obtain a low cross‐polarization level. When the patch antenna is totally covered with a dielectric, it can be operated at lower frequencies without tuning antenna dimensions. The simulated results show that as the relative permittivity of the dielectric is increased from 1 to 9.2, the antenna operation frequency is reduced from 4.25 to 2.38 GHz, and the cross‐polarization level is lower than −25 dB for each operation frequency. Based on such an antenna, a 1 × 8 dual‐polarized phased array is developed. The simulated results indicate that for each polarization mode, the gain variations of the array are less than 2 dB when the main beam is scanned from 60° to −60°; bedsides, a cross‐polarization level of less than −20 dB is also achieved. An array prototype is constructed, and measured data validate the simulated results.