The microwave plasma cathodes (MPC) dedicated to high‐current ion sources are characterized by long lifetime with reactive gases and a compact structure. An Ishikawa‐type MPC developed at GSI Darmstadt coupled with the CHORDIS ion source is presented. The electron current of the MPC is extracted from a dense plasma generated under electron‐cyclotron‐resonance condition. The axial magnetic field is produced by permanent magnets and ferromagnetic components. The 2.45 GHz microwave power (some tens of watts) is introduced into the plasma chamber via a coaxial line ended with a helical antenna. Experiments with argon and oxygen gas are presented and discussed. ©1996 American Institute of Physics.