Conformable phased array antennas for microwave hyperthermia

We consider conformable phased array applicators. These applicators radiate into an environment consisting of a bolus layer used for cooling, followed by layers of skin, fat, and muscle tissue, which in general may be nonuniform and heterogeneous. Consequently, the actual tissue enviroment is complex. For design purposes, it is advantageous to work with a simpler model incorporating the coarse features of the tissue geometry. In order to design conformable phased array applicators, we propose the use of a model consisting of a cylindrically layered region of dielectric material, illuminated by aperture sources in a conducting circular cylinder that surrounds the tissue. Any number of apertures may be excited with arbitrary amplitude and phase in order to achieve a desired focusing effect. Because of the lossy characteristics of fat and muscle tissue, the signal produced by the aperture sources will decay to insignificant levels before reaching the opposite side of the circular conducting cylinder. Thus, the model is intended to mimic the near-zone region immediately in front of the cylindrical applicator, and can be used to study parameters associated with the curvature of the ground plane, the materials comprising the tissue layers, or the degree of focusing possible.