A system and corresponding method for creating hyperthermia in a selected position in target tissue using the application of electromagnetic radiation (EMR) in the HF, VHF and UHF microwave region and phased array steering includes an array of applicators and a single channel EMR radiation energy source coupled to at least one of the applicators of the array. A variable reflective termination device is coupled to at least one of the applicators so that a user can vary the energy radiated from the coupled applicator to steer the heating region in the target to a desired position in the target. Several different applicator arrays are suitable for use with the system, and comprise generally cylindrical annuli which emit radiation toward a central axis. Parasitic applicators with variable reflective termination devices can be used in the applicator array along with at least one applicator directly coupled to the energy source.