In satellite communications, it is becoming challenging to provide the tracking performance which is required for Non-Geostationary Orbit (NGSO) constellations with the traditional Satellite Communications (SatCom) On The Move (SOTM) terminal structure which employs bulky parabolic antennas. On the other hand, in terrestrial networks, the single omnidirectional communication with User Equipment (UE) does not provide enough throughput to fulfill the need for higher speed connections. As a consequence, manufacturers started to invest in developing new terminals which use phased array antennas to enable beamforming to increase the directivity and null the interference in terrestrial networks and to provide rapid tracking performance as well as seamless handovers in SOTM. However, this generates new challenge as these antennas change beam patterns depending on the beam steering angle. It is not trivial to evaluate the performance of beamforming antennas since the measurement of the high number of beam patterns that the phased array can form in all directions is time consuming. In this paper, we propose a methodology to measure a large number of beam patterns of a phased array antenna in a more time efficient approach compared to traditional antenna measurement methods. The measured patterns can be used to evaluate the antenna performance and capabilities in different conditions and verify the terminal ability to fulfill the requirements specified by the standards.