Experimental evaluation of a dual-band phased-array system for focused microwave thermotherapy

This study presents an experimentally validated dual-band focused microwave thermotherapy (FMT) system capable of operating at both 100 MHz and 434 MHz within a single phased-array platform. The proposed system features a dual-band applicator array designed to support resonant operation at widely separated frequencies, thereby enabling the treatment of tumors varying in depth and size without the need for hardware modification. A time-reversal (TR) based excitation method was employed to determine the optimal phase and amplitude weights for each channel. Experimental phantom measurements demonstrated accurate field convergence at both frequencies, with focal spot sizes and positioning errors consistent with fundamental electromagnetic diffraction limits. Specifically, the 100 MHz band produced a broad focal region suitable for deep-seated targets, whereas the 434 MHz band generated a compact focus appropriate for high-resolution targeting at shallower depths. These results indicate that the proposed dual-band system offers enhanced adaptability compared to conventional single-band hyperthermia devices, providing a promising platform for future patient-specific cancer treatment.