The paper presents some optimization approaches to the electromagnetic wave focusing in heterogeneous biological tissue model. The model of human arm was used for investigation. The possibility of focusing of electromagnetic wave optimisation is strongly connected with investigation of electromagnetic wave propagation through complicated heterogeneous biological structure. Firstly we concentrated on the influence of particular structures thickness on scattering parameters value which gives us information about transmission and reflection of electromagnetic wave on interfaces of structures which differ by dielectric parameters. The next simulation showed the influence of water bolus placed on the arm model surface on values of SAR and consequently the possibility to avoid the overheating of upper region of arm model in the process of microwave hyperthermia. The next step connected with possible optimisation of electromagnetic wave focusing showed the influence of metamaterial structure placed in the front of microwave patch antenna used in role of microwave hyperthermia applicator on the electromagnetic wave focusing. The simulations were done for various numbers of metamaterial structures and various distances from arm model. Finally we simulated the focusing accuracy in the case when the combination of water bolus with metamaterial structure was used.

In this paper is using numerical simulations investigated effect of different composition of layered biological structures in human arm model and microwave applicator modification on the absorption of electromagnetic energy and thus specific absorption rate (SAR). First part of this paper is focused on influence description of different width of human arm structures on electromagnetic field propagation. The second part of the article deals with a possibility of focusation increase in the same human arm model using unique artificial structuresmetamaterials. The metamaterial structures based on the split ring resonator approach are used for optimization of microwave generator characteristic. The main field of the study is absorption of microwave-frequency field by means of simulations performed in CST Microwave Studio environment.

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