A planar covered multi-slot-array heat applicator with beam scanning capability for interstitial microwave hyperthermia

A planar covered multi-slot-array heat applicator with beam scanning capability is developed for interstitial microwave hyperthermia. The interstitial applicator is based on multi-slot-array structure, and beam scanning capability is added by gradual variation of the slot sizes. Through the choice of input frequencies, concentrated beam can be generated at the designed slot positions, which provides focused heating as well as additional dimension of beam control. A low permittivity dielectric cover is placed on top of the slot arrays to double in function as a protective layer and a dielectric lens which helps to flatten the wavefront to allow the microwave radiation deeper into the heating material. The measured infra-red images and thermal distributions confirm the beam scanning capability of the proposed applicator. It is also shown that the heating volume and uniformity can be improved by the proposed beam scanning applicator compared with the fixed beam applicator using uniform slot arrays.