An ATE testing system (900, 1000) for millimetre wave (mmW) packaged integrated circuits (820) includes: at least one packaged integrated circuit (820); a radio frequency, RF, socket (700) configured to receive the at least one packaged integrated circuit (820) and facilitate routing RF signals thereto via at least one input connector and at least one output connector; and at least one interface configured to couple a tester to at least one packaged integrated circuit (820). The RF socket (700) includes a mmW absorber (1010) located adjacent the at least one output connector of the RF socket (700).