AbstractTo realize the requirements of 5G MIMO technology for high‐performance antennas, a novel high‐gain transmissive array antenna with conformal capability is designed in this study. The antenna consists of a single‐layer dielectric‐based conformal transmission array and a substrate‐integrated waveguide filter antenna. The transmission array is composed of a cross element and spiral elements that can achieve conformal capability. Each metasurface element is a single‐layer medium, and the same metasurface patches above and below are connected by four metal pillars. A filter antenna array fed by a substrate integrated with a waveguide fed by small‐scale low‐temperature cofired ceramic technology is used as the feed antenna of the transmission array. The physical test results are consistent with the simulation results, and the directivity of the antenna is greatly improved. The frequency range where the reflection coefficient S11 is less than −10 dB is 26.6–29.1 GHz. At the center frequency of 28.0 GHz, the gain of the conformal antenna array is greatly improved, and the peak gain is increased from 8.2 to 24.5 dB. The sidelobe level is substantially suppressed. Its high gain and beamforming characteristics make it have a high application value in 5G MIMO technology.