An ice and/or frost preventing system for positioning in an airflow tunnel having an air inlet includes a plurality of waveguide passages positioned in the airflow tunnel; an air filter positioned in each waveguide passage; a microwave energy source coupled to each waveguide passage; a first screen positioned in the airflow tunnel upstream of the plurality of waveguide passages; and a second screen positioned in the airflow tunnel downstream of the plurality of waveguide passages. The microwave energy sources and the first and second screens create a guided, standing wave, microwave energy that substantially prevents at least one of ice and frost from forming on the air filters. A turbine system including the ice and/or frost preventing system is also described.