Radar, satellite communications, and 5G NR use advanced antenna systems (AAS) with phased array antennas for beamforming. Hybrid beamforming combines the flexibility of digital beamforming with the efficiency of analog beamforming. Increasing integration enables compact and cost-efficient AAS. To achieve accurate, reliable and efficient beamforming, it is necessary to understand and compensate for the nonlinear behavior of RF components. While discrete components such as phase shifters, switches and amplifiers are tested conducted, highly integrated frontends with antenna-in-package (AiP) and system level tests require over-the-air (OTA) testing. This application note covers the benefits of Rohde & Schwarz’s portfolio of conducted and OTA test solutions and how they help to optimize beamforming.