Optimized Phased Antenna Array for Deep-Targeted Microwave Hyperthermia in Brain Tumor Therapy

Abstract

This study develops an optimized personalized microwave hyperthermia framework for glioblastoma treatment, integrating a 19-channel radiofrequency array of geometrically and electromagnetically co-optimized cosine-curved dipole antennas. We initiated the design by optimizing the conductor geometry (amplitude, wavelength, and phase offset) to reshape the current distribution. Concurrently, resonant coupling loops were incorporated to provide additional degrees of freedom for impedance tuning. This combined approach establishes a synergistic mechanism, thereby overcoming the limitations of ultra-high-frequency dipoles and achieving enhanced impedance matching at 2.45 GHz, which is demonstrated by an S₁₁ value of −19.2 dB obtained through particle swarm optimization. The semidefinite relaxation (SDR) algorithm optimizes channel excitations under a 72-W total power constraint to maximize the tumor-specific absorption rate while minimizing exposure to healthy tissue. Multianatomical electromagnetic–thermal validation confirms a treatment planning time of 0.31 min, representing a 50% speed improvement over particle swarm optimization. This delivers a precise 41.69°C mean tumor temperature with superior targeting quantified by a specific absorption rate amplification factor (SAF) of 4.46 and a hotspot-to-target quotient (HTQ) of 0.81. Parametric analysis reveals depth-progressive SAF attenuation from 4.33 at superficial positions to 2.67 at 4 cm depth alongside improved large-tumor targeting achieving SAF 4.63 and HTQ 0.75 at 5 cm diameter. A pediatric model exhibits heightened electromagnetic sensitivity showing SAF 5.02 versus less than 5% variation in adult models, establishing a clinically translatable pathway for precision brain hyperthermia. This work is a computational study validated entirely through in silico simulations, without involving in vivo or clinical experiments.