Partition lens system for focusing field from PSIRA with TSVS feed on biological target

Abstract

The Impulse Radiating Antenna (IRA) is suited for radiating picosecond electromagnetic impulse for the treatment of skin cancer. The feed of the reflector IRA is an ultra-wideband antenna. In this proposed work, a Tapered Slot Vivaldi Shaped (TSVS) feed arm is designed for Prolate Spheroidal Reflector (PSR). The feed antenna is placed at the first focal point of the PSR. The picosecond electric pulse is launched from the first focal point and is focused at the second focal point where the target is placed. Next Partition dielectric lens system is designed to enhance the electric field and reduce the spot size of the focused pulse. The TSVS feed arm is matched from 500 MHz to 10 GHz. The 3 dB angular beam width of the proposed IRA with 50 cm aperture diameter is 4.3°, and the radiation efficiency is 63% at 10 GHz. Simulation results show that the full width half maximum of electric field intensity is reduced by 57% in the axial direction and 20% in the lateral direction when compared to the conical feed IRA without lens. The three layer partition lens system greatly reduces the spot size from 1.187 to 0.75 cm, when compared to five layer spherical dielectric lens and increases the electric field by 65%.