An extensive investigation of front-door protection devices i.e. limiters has been made. The report contains both new results and summarizes results from previous measurements done on limiters. Both HPM and UWB measurements on various limiters have been done in order to characterize the limiters. The measurements show that not all limiters are suitable as protection against HPM and UWB pulses. The limiters that were found to provide the best protection are limiters based on diode technologies. PIN- and Schottky-diodes generally shows very good performance and they fulfil many parameter restrictions that have been set by FOI. This report also includes initial results from LNA (Low Noise Amplifier) susceptibility testing. HPM injection measurements have been done on one type of LNA. The destruction levels of the LNAs were investigated by changing different input parameters, such as pulse width, biasing etc. The result shows that there are up to 9 dB in difference between destruction levels, depending on the input parameters. A further study on LNAs will be done, the study will also be expanded, and in total about 150 LNAs from three different types of LNAs will be tested.