A Conformal Antenna Array with Adjustable and Small-size Focal Spot for Head Hyperthermia

A microwave near-field focused antenna array operating at 915 MHz is proposed for head hyperthermia. The proposed array consists of 2×4 identical microstrip antenna elements, whose spatial distribution is helmet-like. With different excitation phase of 8 elements, the focus position for the antenna array can be adjustable, which makes the proposed array suitable for diversity of tumor locations. When the total input power of the array is 32W, the maximum temperature at the focal spot can reach 44℃, which can effectively kill cancer cells. Each power loss density -3dB focal spot region is around 2×2×2cm³, which causes less damage to normal cells surrounding cancer cells. The focal spot size of the proposed antenna array is much smaller than that of other near-field focused antenna array. Full-wave simulation verifies the feasibility of the near-field antenna array with adjustable focus position for head hyperthermia.