Focal Spot Size Evaluation of a Focused Lens in Human Body

In hyperthermia therapy, it is significant to focus microwave to the targeted therapeutic spot as to avoid high temperature or hot spots at the surface or surrounding healthy tissues. This paper presents near-field focusing concept which is implemented using converging dielectric lens and a λ/2 dipole at 2450MHz as a radiating element to generate small focusing spot. Lens's diameter (D
L
) of 30, 50 and 70 cm have been designed and simulated in free space and inside human body equivalent phantom. The simulation results are presented and shown that larger size of D
L
resulted in smaller focal spot size. It is observed that electric field (E-field) intensities are increased at the focal point with larger D
L
of the antenna.