High‐gain directive antennas are used to support point‐to‐point long‐range wireless communication channels. In typical designs, the array factor plays the key role, while individual elements’ layout is simplified. Herein, a four‐element phased array is demonstrated, where a volumetric form factor of each element is taken as an advantage to elevate the antenna gain while keeping the device footprint small. The two‐step design process, encompassing a genetic topology optimization and finite tuning with a particle swarm algorithm, is applied and subsequently demonstrated. This shows that exploring the third dimension allows obtaining more than 25 dB isolation between adjacent radiating elements and, at the same time, grants them highly directive radiation patterns. This operation principle is verified by demonstrating a large number of resonating multipoles constructively interfering to create a directional beam. The antenna with a πλ2 aperture demonstrates more than 13 dB gain around 3 GHz frequency range. Antenna elements are 3D printed in resin and then metallize electrochemically. Additive manufacturing of complex volumetric architectures with a small interelement spacing allows implementing new devices, encompassing the advantages of resonant approaches and arrays factors. Miniaturized 3D antenna array devices can be used in wireless communications where controllable beam properties are demanded.