A novel antipodal Vivaldi antenna operating at an ultra‐wideband of 5.2 to 40 GHz with high gain and miniaturized size is presented in this article. By introducing a pair of radiation arms with maple‐leaf edge shape, the antenna gain is increased by 1 to 3 dB over the upper operation band (10‐40 GHz) compared to the normal antipodal Vivaldi antenna (AVA). To remain the beamwidth while increasing the gain, two rows of specialized symmetrical metallized vias are loaded on the two inside edges of the exponentially slot. By loading the resistors between the top and the bottom planes, the side lobe level at E‐plane is reduced by 3 dB. This proposed maple‐leaf antipodal Vivaldi antenna (MAVA) has the miniaturization size of 0.66λg × 0.68λg × 0.003λg. According to the simulated results, the relative bandwidth of the reflection coefficient less than −10 dB is 154%, and the gain is higher than 10 dBi over the 22 to 40 GHz band with the maximum value of 14.3 dBi. The antenna design is validated by the measurements.