The active component (400, 500) of a radio device comprises a first transistor (Q1) and a second transistor (Q2). The differential input of the active component comprises a first input line (RF+) and a second input line (RF-), of which the first input line is coupled to the base of the first transistor (Q1) and the second input line is coupled to the base of the second transistor (Q2). In order to match the input impedance there is cross-feedback (Rfb') between the first transistor (Q1) and the second transistor (Q2).