Abstract: The present invention relates to a microwave electronic device (1) comprising a metal enclosure (2) having a bottom (21) and a lid (23) and containing an electronic circuit board (3) disposed substantially parallel to said bottom and to said lid, said circuit board having: conductive bottom and top grounding layers (41, 42) respectively disposed on bottom and top faces (31, 32) of the circuit board, and perforations (7a) transverse to said faces of the circuit board and delimited by conductive walls (71) for electrically interconnecting said layers (41, 42). At least some of said walls (71) are electrically connected to the lid of the enclosure by conductive grounding members (8a). Each conductive member (8a) has a metal blade covered with a material (13, 13?) for absorbing microwaves.