Abstract: This paper presents a focused circular antenna array for the targeted hyperthermia of lesions in the human leg. The circular array consists of eight planar subarrays arranged in rotational symmetry. To validate the targeted heating performance, a digital leg phantom surrounded by coupling liquid is placed within the array cavity. The excitation distribution of the array is optimized by using the constrained extended method of maximum power transfer efficiency (CEMMPTE) for lesions of diverse sizes and locations. Simulation and experimental results demonstrate that the proposed array effectively focuses radiated energy onto the target regions. Furthermore, the focal spot size is steered by the excitation distribution instead of adjusting the operating frequency, and such a scheme has potential application in target microwave hyperthermia.