Optimal Design of a Hexagonal Antenna Array for Regional Microwave Breast Hyperthermia

In this letter, a hexagonal antenna array is designed for regional microwave breast hyperthermia. The array consists of six subarrays operating at 2.45 GHz, and it is used to deliver microwave energy into a targeted region in the digital breast phantom surrounded by a coupling fluid. The optimized distribution of excitations (ODE) for the antenna array is obtained by the extended method of maximum power transmission efficiency (EMMPTE). The proposed EMMPTE is based on a new objective function by maximizing the ratio of the radiated energies at discrete points selected in the target region over the total input power of the transmitting array, the ODE for the antenna array can be obtained through solving an eigenvalue equation. Simulation and experiment show that the proposed method can effectively deliver microwave energy into the targeted region in the breast phantom and form a focal spot without introducing other hot spots in the remaining region, verifying the applicability of the proposed method.