Analysis of the Radiation Leakage for a Four-Aperture Phased-Array Applicator in Hyperthermia Therapy

We develop a criterion for the justified neglect of the field leaking from the regions between the horn apertures in a phased-array applicator. The condition is (b/delta)psi <<1, where delta is the skin depth of the conductive material, b is the radius of the torso or limb, and psi is the wedge angle between the horn apertures.