## 2 Methods
### Simulation Setup
where \(k\) is the thermal conductivity in W/(m\(\cdot\)K), T is the tissue temperature in \({}^{\circ}\)C, \(Q_{m}\) is the specific metabolic heat generation rate, SAR is the specific absorption rate, C\({}_{p}\) is the heat capacity of the tissues in J/(kg\(\cdot\)K) and \(\omega_{\rm b}\) is the perfusion rate given in 1/s. \(\rho\) is the tissue density (kg/m\({}^{3}\)); \(\rho_{b}\), C\({}_{p,b}\) and \(T_{a}\) are the density, specific heat capacity and the temperature of the blood, respectively. All these values are specific to each tissue. The specific absorption rate SAR is related to the energy in the form of the \(\mid\)E\(\mid\)-field deposited into the tissue and is calculated by the electric field:  
\[SAR=\frac{\sigma\cdot\mid\)E\(\mid^{2}}{\rho} \tag{3}\]  
where \(\sigma\) is the electrical conductivity (S/m), and \(\rho\) is the tissue density (kg/m\({}^{3}\)). As the equations indicate, the temperature depends on the electric field and the conductivity of the tissue. Therefore, a strong and focused \(\mid\)E\(\mid\)-field is desired. For this simulation, we used the Pennes algorithm for 200 s, and the thermal parameters for the tissues were assigned automatically using the Sim4 Life software database. A power of 5 W was applied enough to increase the temperature by 1 \({}^{\circ}\)C.  
Furthermore, we applied the patch antenna configuration to a rat of 196 mm \(\times\) 50 mm \(\times\) 55 mm with a mass of 198 g. Rat 3D models were provided by the animal model from the library of Vizoo (ITIS foundation, Zurich, [[https://itis.swiss/](https://itis.swiss/)]([https://itis.swiss/](https://itis.swiss/)), accessed on 18 February 201), by using the \"Big Male Rat\". This model consisted of 52 tissues with the respective electrical properties. The boundary condition at the rat were set with the background of Neumann boundary condition with a Heat Flux of 0 W/m\({}^{2}\), and the initial condition for the air was set to 25 \({}^{\circ}\)C. The use of the Neumann boundary condition fixes the heat flux at the interface; the sign of this value determines whether the flux flows into or out of the material. This boundary condition used with a heat flux of 0 W/m\({}^{2}\) results in thermal insulation of the boundary, removing the need for water bolus. The skin had a heat transfer rate of 7969.16 W/m\({}^{3}\)/K. In the rat model, we also included a cancer-mimicking tissue, which was the target tissue for the RF heating system, the cancer tissue had an electrical conductivity and permittivity of 1.05 S/m and 62.85, respectively, at 300 MHz and electrical conductivity and permittivity of 1.2 S/m and 59.6 at 1.06 GHz, the conductivity and permittivity values of the cancer tissue was selected based on the measurements in ref. [32]. The cancer tissue was modeled by using part of the large intestine, and the final model was carried out by intersecting a sphere and the large intestine, separating the normal tissue and the cancer tissue by changing the electrical properties as described previously. We used the same simulation setup as the phantom simulations for both the EM and temperature computations, except for using a power of 10 W.