The present invention relates to a self-adaptive band-pass filtering device in a microwave signal transmitter and/or receiver, the receiver being connected to a microwave signal receiving antenna connected to the input of a low-noise amplifier, a mixer that receives, on the one hand, the output signal of the low-noise amplifier and, on the other hand, the signal from a frequency synthesizer, characterized in that the self-adaptive filtering device comprises, upstream of the amplifier, on the one hand, at least one filtering means having at least two different frequency bands and, on the other hand, means for selecting either a filtering means or one of the frequency bands depending on the frequency of the signal to be received.