There are several different ways for cancer treatment including operation, radiation therapy, chemotherapy, gene therapy, immunotherapy, ablation and hyperthermia. Techniques utilizing temperature elevation over the tumor region are usually called as thermal therapies. In this paper, we will focus on hyperthermia which is one of the promising cancer treatments utilizing the difference of thermal sensitivity between the tumor and normal tissue. In addition, microwave energy is a heating source used for localized hyperthermia. Depending on the position and size of the target tumor, several types of antennas, which radiate microwave energy to the target, can be selected. This paper describes two types of heating schemes which can be used with microwave energy, and provides brief explanations of the basic engineering involved. In addition, methods used for evaluations of antenna performance are described.