Abstract: Heating pattern uniformity is provided in a coaxial microwave hyperthermia probe by varying the open area in the outer conductor in an axial direction such that there is a maximum open area in the axial center portion. The variations may be provided by winding an outer conductor in a helical pattern with a variable pitch or by cutting openings of axially varying size in a solid outer conductor. The invention is applicable to both flexible and rigid probes.

Abstract: An isolator for insertion in a coaxial cable between an RF generator and a device employing RF energy provides isolation against DC and low frequency (60 Hz) AC while passing the RF energy with low attenuation and a low reflection ratio. The isolator has a longitudinally extending central conductor spacedly surrounded by an inner conductor. The central conductor and inner conductor are connectable to the ends of the center conductor of the coaxial RF cable. A first outer conductor of the isolator spacedly surrounds the inner conductor and a second outer conductor spacedly surrounds the first outer conductor. Insulators are provided between the central and inner conductors, between the inner conductor and the first outer conductor and between the two outer conductors. The outer conductors of the isolator are connectable to the sheath of the coaxial RF cable.

Abstract: Heating pattern uniformity is provided in a coaxial microwave hyperthermia probe by varying the open area in the outer conductor in an axial direction such that there is a maximum open area in the axial center portion. The variations may be provided by winding an outer conductor in a helical pattern with a variable pitch or by cutting openings of axially varying size in a solid outer conductor. The invention is applicable to both flexible and rigid probes.