The invention relates to a field-effect transistor having a higher efficiency than the known field-effect transistors, in particular at higher operating frequencies. This is achieved by electrically connecting sources of a plurality of main current paths by means of a strap line (SL) being inductively coupled to a gate line (Gtl) and/or a drain line (Drnl) for forming an additional RF-return current path parallel to the RF-return current path in a semiconductor body (SB). The invention further relates to a field-effect transistor package, a power amplifier, a multi-stage power amplifier and a base station comprising such a field-effect transistor.