Many technological applications based on the use of intensive microwave radiation are connected with high temperature material processing. As a rule the microwave power being absorbed in the material must provide heating of the processed zone up to rather high temperatures (> 100º c) within fairly small time intervals. hese requirementsare dictated either by the nature of the process ( surface transformation hardening, joining ceramics and metals, cutting materials ) or by necessity to provide sufficiently large process output ( coating of materials, joining of dielectrics, melting, etc.). The upper value uf the exploited radiation intensity is limited by effects of gas breakdown near the treated surface. The considerable part of microwave rad.ation can be absorbed and dispersed by the discharge plasma, hence microwave energy supplied to the material significantly decreases.