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%.
The application of pulsed electric field is emerging as a new technique for cancer therapy. The irreversible electroporation is the major bioelectric effect to induce cell death. The pulsed electric ...field is transferred to target deep tissue non-invasively and precisely when the pulse duration is in picosecond regime. In this proposed work, the intense electric field with 100 ps pulse width is used for irreversible electroporation. If the electric field strength increases, the pore in the cell membrane enlarges, causing a loss of membrane intactness and the direct killing of cancer cells. This phenomenon is explored by molecular dynamics simulation. The electric field in the range of 0.8–5 V/nm is used for membrane dynamics. The membrane deformation occurs at the electric field of 5 V/nm. Picosecond pulsed electric field has a wealth of ultra-band spectrum, with extended time and enhanced spatial resolution and low signal distortion. The ultra-wide band antenna is used as a pulse delivery system for non-invasive skin cancer therapy.
A high-intensity electric pulse with subnanosecond and picosecond durations may induce electroporation of an intracellular organelle while the integrity of plasma membrane in a biological cell ...remains intact. In this paper, selective electroporation of organelles under intense picosecond electric pulse (psEP) is theoretically studied. We construct a simplified axisymmetric model of a biological cell containing two organelles of different sizes and investigate the electroporation processes of the cell with a finite element method. The induced transmembrane voltage (TMV) and pore formation dynamics on the biological cell membrane are comparatively analyzed when the cell is exposed to sufficiently intense electric pulses of nanosecond and picosecond durations, respectively. From our results, selective electroporation of organelles can be clearly observed when the cell is affected by an intense psEP. In contrast, the electric pulse of a few hundred nanosecond duration can electroporate the plasma membrane of biological cell much before organelle membranes regardless of the magnitude of the pulse. By regulating the intensity of electric pulse with two different durations, effective pulse parameters can be obtained to realize selective electroporation of intracellular organelles or plasma membrane. Our study demonstrates the selective electroporation of organelles of intense psEP and may provide guidance for further development in experimental and theoretical research. Furthermore, the applicability of the quasi-static model used to calculate the TMV under the stimulation of a few hundred psEP is first illustrated in this paper.
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