Front-end power overload protection is a vital issue in any electro-magnetic sensor. The issues around active electronically-steered arrays are more recent and pose new threats. Different categories of threats can damage the sensitive electronics in the phased-array radar, like hostile high power electro-magnetic (HPEM) pulses or the radar’s own transmitted signal. Protection measures can be integrated in different parts of the radar system. To obtain an effective EM protection mechanism it is crucial to distribute protection measures over all relevant system parts. Experimental research and development is carried out on front-end protection mechanisms in the radome with frequency selective surfaces (FSS), the antenna face and in front-end electronics by solid-stateabsorptive limiters and the design of key components, like low noise amplifiers and switches in robust gallium nitride technology.